Privacy Statement

Approach speed

Mike Martin replied
I think the key point here as brought up by several people, is to be stable on the approach. If you are not being pushed, fly your normal approach speed and configuration from the final approach fix. If the controller is pushing you to the marker becuse of faster traffic behind you, that's ok. Just remember you have got to land this thing. If you are flying fast and the runway is wet or icy(that's why you are shooting the approach in the first place)it's going to take you longer to get slowed down, land and safely turned off the runway.

The big guys get pushed all the time too. It's routine to have the controller ask for 180kts to the marker. But the big guys pick a point, usually at a 1000 ft agl, where they must be configured and stable so that can land and safely exit the runway in a minimum amount of time.

Do what you need to do to stay in the landing queue but remember when you break out at minimums, you should be configured and on speed to make a safe landing.

By the way when shooting an ILS to minimums I use 2/3 flaps and 100kts.

GMAS 337Skymasters Club replied
Use that little blue line on the A/s indicator... its 90 kts otherwise... for everything... on approches...

kevinmcdo replied
90 kts sounds kind of slow for instrument procedures. It might be OK for a 172, but stability will improve if you fly it faster. The blue line has nothing to do with approach speeds.

I use 120 for holds, and 110 for the approach. Prior to FAF I have 1/3 flaps. At glide slope intercept I drop the gear and go to 2/3 flaps - that will set you up nicely to follow the glideslope. About a 600 FPM descent will hold the glideslope in no wind conditions. At DH you're going to have to chop the power way back to get slowed down to a reasonable landing speed of 75 to 85 kts. I don't use full flaps for instrument approaches - at DH there's too much going on to be changing the aircraft configuration.

If you really want to do full flap landings, you're probably better off with a slower approach speed to keep safely in the white arc.

GMAS 337Skymasters Club replied
Ahhhh say what... why in the world would you want to go racing around the holding pattern at 120kts... and the last time I made my approch... according to the POH and older flight manual.. its 90kts... almost exactly where the blue line is... at that speed if you drop the gear... with 1/3 flaps... you get 500 ft a min down... right on the numbers... flying at a faster speed is putting you outside the inst approch catagory... as its based on the Vso with gear and flaps down... now you can fly faster but, its going to use more fuel and if they make you hold at some marker for a while... its awful nice not to run out of gas... and have to have a emergency which will mess up everyone else... in the system... smile...

kevinmcdo replied
Fair points ... a 110 kt approach speed puts you into category B which sometimes increases your minimums for the approach, ... and flying 120 kts instead of 90 in the hold will burn more fuel. Fortunately the longest hold I've received was only 20 minutes.

My preference for the higher speeds is for stability. In bouncy weather I feel the tradeoff is worth it.

You seem to be stating that the POH suggests 90 kts for instrument approaches. The POH for the T337G doesn't address instrument approaches at all (nor has any other POH that I can recall reading). Are you saying 90 kts because it's roughly 1.3 x Vs0, or am I missing something?

GMAS 337Skymasters Club replied
Kiv...
Well if you have been flying inst. for a long as I..... you should already know from the training books and your instructor that their are settings and speeds that you are supposed to do...
Now the 90 kts approch is quite stable and meets the requirments... also it is the closest that is called out for in the proceedures... as to the rule of 90 kts for the POH.. if you check the military version... which we used to use as a supplment... you will find that they use that speed for just about everything... and the gov payed some guy lots of money to find out what it was..for the skymaster.. so I think it is safe to assume it is what you should be using too... Good luck on your isnt training the skymaster is a good platform to work from... G.M.

kevinmcdo replied
"Well if you have been flying inst. for a long as I....."

Not a good sign when the conversation reaches this point. :) You may well have more time than I, and I didn't intend to be disrespectful of your opinion.

I thought you stated that there was an instrument approach speed cited in the POH - I only asked for the reference.

"if you check the military version..."

Any idea where I can get this? Sounds like it would be worth reading. Or are you referring to the Cessna manual for the O-2?

"Good luck on your isnt training the skymaster is a good platform to work from..."

Thanks, I agree the Skymaster is a good instrument platform. I'm not sure how I gave you the impression that I'm in instrument training, because I'm already IFR rated. Maybe the original poster's message is where that came from.
GMAS 337Skymasters Club replied
Kevin.... ops I thought that you were a student.. sorry...
Yes the ops manual can be had for the O-2... some of the other guys have them...
and in their they suggest the holding and approch speeds.. even give a little
picture diagram of the speed on the pattern...

No I usually don't do the I have more time that you.. thing.. and
I am not insulted... nor ment any insult... I thought from your question that
you were a student... and had not looked at the approach plates for the cat and speed..
and holding patterns... I again say that it is more practicle to keep the fuel useage donw
and like a blind man with a white/red cane... to go zooming into a approach at a higher speed..
will get you into trouble quicker... than if you are somewhat more conservitive...

I know the cessna POH does not have any approch speeds in them as they defer that info to the inst pilot.. to figure
out from the approch plates and logical deduction... as to the stability... of the plane at a higher speed than that of a slower speed...
I find that the plane is better than most at the 90 kts.. approch speed.. and in turbulance.. it is better again to feel your way
along than to go zooming in... what we want to do here is to have a stable approch... while still not exceeding the FAA's recomended
rate... what we do want is the powere in reserve to take care of that missed approch or the go around.. here the skymaster has the ideal amount..
it can maintain 500 ft a min in either direction... up or down... while still holding the 90 kts speed... so I guess the faa says it in one word
control... I have found that in IFR except for crusing... speed is not a option... the controllers are expecting a constant speed and rates of climb or decent...
I think you would agree... but, if 120 kts is more to your liking... its not to say it can't be done... except as we said before it changes your catagory... and they ... the controllers
are going to expect you to maintain it... even while you climb at 500 ft a min... plus or minus the up or down drafts... G.M

SkyKing replied
Operational limits being what they are for your particular airplane, you should probably first acquaint yourself with and/or review the 'Airspeed Limitations' found in Section 2 of the POH. Next, review your 'Airspeeds For Emergency Operations' as found in Section 3 of the POH, and then the 'Speeds For Normal Operation', keeping in mind the conditions you find yourself in with respect to turbulence in the descent and approach.

For the P337 that we fly, because of the addition of Robertson STOL, we're limited in the first 1/3 Flaps at a max airspeed of 143 Knots. Also, if you're at max gross weight, the maneuvering speed is 139 Knots, and of course, the max gear extension speed is 140 Knots. Since these max limit speeds are all fairly close, as soon as we get through 140 Knots, down comes the gear... the reason: if you have a problem with it in IMC, more time to handle the situation. Do you want to swing the gear at the outer marker, so close in, and discover then you've got a gear extension problem? You'll have your hands full. Better planning dictates getting the gear down farther out...when... it's your choice, because steeper descents can be made with the gear extended, also allowing for keeping the engines warm, and in the case of the P-models, keeping the cabin up.

As GMAs points out in this thread, 90 Knots is what the POH recommends for landing approach. It just so happens that in our P337 with Robertston/STOL, we can't drop the second notch of flaps until were at 94 Knots, and of course Blueline for single engine best rate of climb is 89, so again, 90 Knots is a good airspeed for final approach on the ILS, unless the controller has you expediting, which is often the case. So, in the final analysis, it comes down to 'conditions' dictating the situation.

By the way, I see elsewhere in this thread that someone said they like higher airspeeds in bouncy weather conditions. If you've got turbulence, slow up and save the plane from fatigue, and give your PAX a somewhat stable ride.

Bob Cook replied
That's all well and good but it's hard to mix with oil burners and keep the controllers from putting you in a hold for 1/2 hr while he clears the faster traffic.

I have learned 140, 120 , and 90 are the three key speeds. I like 120 on an ils approach only because having used it on other aircraft, 90 at smaller airports. I find the ride is better at 120 for some strange reason. There is a little more energy (or margin) if a go-around is necessary. The gear will go down early if there is no chance of ice.

Aux. Tanks Endurance

Paul Sharp replied

Here are three items of input for what they're worth:
1 - You must fly for about one hour on the main tanks BEFORE using the aux. tanks because unused fuel will return into the main tanks, so I think you have it right when you put "after one hour on the main tanks." If they are full (that is, you haven't flown on the main tanks to use some of the fuel), then the unused fuel trying to get into them from the aux. tank usage will vent overboard, being wasted.
2 - I can fly on my aux tanks for 1 and 1/2 hours at 65% power settings. When the engines start to miss, I switch back to the main tanks. Often I will cycle the fuel pumps on while getting the full flow back after running the aux. tanks down, depending on whether I switched immediately or took a few seconds doing it. Of course, once the engines even out I turn off the fuel pumps.
3 - After landing, I usually have the linemen put 3 gals. each into the aux. tanks so that there is some fuel there to keep the bladders from getting dried out. That way I know what kind of fuel weight is involved (18 lbs. each side), but have the option of not using the aux. tanks when I want to fill the plane with more weight (either passengers or cargo).

Dave Zavoina added
There is no reason to put any gas in the aux tanks because they are aluminum, not bladder type. If you are going to put fuel in the tanks, they should be topped to keep out condensation. I has numerous pinhole leaks in mine when I got it as a result of moisture being left in the tanks.

Paul Sharp then asked
Are the mains aluminum also, or are they bladders? I just went by what a mechanic told me about the tanks being bladders. If that's the case then I won't put any in the aux. tanks.

Dave Zavoina replied
Yes, the main tanks are aluminum also. CE-337's thru 337F's have two tanks per side, mainfolded together and feed the sump in the lower foreward boom (where the sump drain valve is located). G and H models are manifolded along with the early model aux tanks, to form the mains, unles they have the long range tanks, then they would have a fourth, smaller tank, outboard, still all manifolded together.

Consumption

Ernie Martin replied
On a 337 (retractable gear) at 60-70% power cruise at 7,000 - 9,000 feet I burn about 20 gph doing 140 knots airspeed.

Ernie Martin

Jose L. Ichaso replied

I have check very close my 337D performance for a while, and at 8500-7500 feet 20"-21", 2400 rpm comsumption is 20 GPH, doing 150-152 Knots ground speed ( with full long range fuel 4 adults, speed can be lower with aft C.G. ), any more or less is the wind component.
I use to burn 18 to 19 GPH (Using a Shading Digiflo fuel computer) at 1350° EGT, but front engine begin to have a hotter EGT to 1400° (which is peak EGT) so I swith to 20 GPH. Rear engine goes much cooler than front, so I have check the injectors in the front engine and nothing have change.My engines are close to TBO, compression are between 60 to 70 one aft cyl lower, with oil consumption on 1 qt. every 5 to 6 hours on both engines.

James t.Grant replied
Dear John,I get 145-150 KTAS at 7500-8500 ft,22 Inches MP,2400 RPM,22 GPH(admittedly running rich).this gives 4 hours with a comfortable reserve of almost 2 hours(basically the capacity of the aux tanks).I have 3 wheel pants and the HORTON STOL kit.

Good luck

James

john toomey replied
Dear James,
Many thanks for your consumption info.
Your Horton STOL kit and wheel pants sound interesting. What sort of pricing do they come out at.

James Grant replied
Dear Sir,
The Horton cost US$1771 plus freight.I put it on myself with my local IA,we didn't track the hours too closely but 60 would be a good number.The manual says 40 hours,we did not hit any snags so perhaps that is a little optomistic.As for the wheel pants I do not know where you can get them,but perhaps they are the same as the 206 or some other large cessna single.

regards

James

James Grant replied
I forgot to mention that this is for my 336,S/N 145 N3845U so the numbers should be valid.

Early Model 337

Paul Sharp replied
I don't know if MCGTOW is CG stuff or weight or what, but I think you get the same basic capability with the early models as the later ones. Later ones tend to have stuff in them that offsets the additional payload capabilities.

I have a 67 (mine's a Turbo), and "reasonable" value is based on current condition v. what you really have to do to bring the A/C up to shape (if anything, but usually at least something is required), and engine times are relative. My A/C had about 3400 hrs. on it when I bought it, and one engine was O/H'd as part of the purchase and the other had about 920 hrs. on it.

I don't know what "timexed" engines means, but the hours seem reasonable. With only VFR radios and mid-time engines, I would think it wouldn't be more than about $50 - $60K IF everything else is really in shape. I paid $55 for mine counting the engine O/H, but it has gone up in value since then and I am about to put $25k worth of paint, avionics, etc. so it will be much more than the $65k or so I value it at now after that. Mine also had nice King IFR avionics and is deiced, etc.

If the plane is worn and needs work, then it might be only worth $40k - $50k. (I actually bargained to $41 for mine but after the engine O/H and fuel system work it was $55k total by the time I closed the paperwork.) As I said, I figure it has appreciated at least $10k due to what I've done to it since, not counting the stuff I'm about to do.

Check the A/C Blue Book and the AOPA site and some of those things and you'll get a oood idea what it's worth so far as what they'll finance.

Hope that's some help.

airtids replied
Sorry about some of my "Canadianisms". Timexed means that the engines are over TBO. MCGTOW means the gross weight of the aircraft- how heavy can it be and still fly (legally!). Are the prices you're talking US Dollars? As a commercial operator the engines will need to be redone. Can you put TIO360s in place of the IO360s that are coming off? Also, other than STOL kits, what other performance mods are out there? VG Kits, etc.
Cheers, Robin

EGT and TIT for T337

Paul Sharp replied
I have no TIT gauges on my 1967 T337B. And the EGT gauges are merely relative - I use them to determine the peak for a given altitude and settings.
Add to those two items the thinking I use that saving money is relative in the sense that getting there 5 to 10 minutes sooner for each hour of flight saves money just as surely as flying longer at lower settings - and this is a subject on which you'll get many an argument pro and con - but the last article I read in one of the flying rags concluded that flying at 75% is actually more economical than flying at 55% in the long run, etc.
With the above in mind, here's how I set it. My initial climb settings are reduced to book figures after takeoff: 2800 inches and 2600 RPM. When I reach my normal cruising altitude, which for my short weekly flights is around 10,000 feet, I reduce the manifold pressure to 27 inches, which makes for a 75% power setting at a nominal 10,000 feet. If I go higher, then I use the settings in the book for 75% at that altitude. Then I peak the fuel mixture setting using the EGT gauges and enrich until I get 125 degrees below peak.
Until a couple of weeks ago I was enriching for 75 degrees rich of peak, but the club response on this site suggested that 125 degrees will result in longer engine life, so I've been trying to do that. I've noticed a considerable difference in fuel flow readings between the rear and front engines to get that kind of setting, but figure the setting from the EGT peak/enrichen process is probably more accurate than the fuel flow meters. Maybe other readers can throw in some comments that will illuminate this subject more.
I also have begun to do my takeoffs (on normal, long paved runways at the larger airports where I fly most, that is) with no more than 28" MAP. That's also due to input I read here from the "club" suggesting that keeping the Turbo models limited to that setting will result in longer life.

G.M> 337 Skymasters Club added
EGT and TIT are two of the same... if you use the EGT for controling the fire... how would you change the TIT?... would they not be the same as they are in the same pipe... if we analize the system.. we would find that the turbine inlet temp should really be lower than the EGT for it is further away from the exhaust valve... so I think I would use the EGT for my setting...
As far as the power setting... it depends on what speed and power setting you want to use. I would use anything between 2600-2300 rpm and a Mp of less than 28 inches.. to keep it in cruse configuration... most are running around 55-75% power... and it seems to be a nice setting for everything.. engine life, fuel... etc.. As each of the airplanes have changed in years the settings will be somewhat different. To use anothers settings would only be a guideline... as the previous reply is the correct way to set your engine up.. for cruse flight after getting 75% powere or below...
To extend your range... by leaning further... is possiable but, I would only do it when needed... as it does seem to shorten the life of the engine If I were running out of gas and the range and endurance is what I needed to be safe... you be I would lean out to peak.. but, then again I would be down around 40% power...too... it does you no good to save the engine and crash the plane because you run out of fuel.. then again I would think that pre-flight planing is in order here... to insure that it didn't happen...
As to fuel flow, why do you need to have more fuel...in the engine in turbo engines... you need it because the intake air is heated due to compression from the turbo... and it is a leaner charge in the cyc because of this... fuel as we used to know it provided two things... no three.. cooling of the engine.... lubercation of the heated sections...(lead) and control of the burning in the cyc...(to prevent pre-ignition...knocking) and damage to the internal parts...
When we lean... we reduce the fuel that controls this and to increase the power for the same amount of fuel we cause the fire inside the cyc to get hotter.. and inversely the pressure goes up... to a pulse (explosion) instead of a timed duration... or as we call it a burn. The damage is done when we burn all the fuel... (at peak) and when we are at maximum power.... like cars of old... you could hear them ping... that was the explosion going off inside the cyc... but aircraft engine... are more fragle and work harder.. and thus cant stand to have this pulse... let me put it this way... would you rather have someone push you while you sit in the waggon... or would you rather have someone use a sluge hammer and hit you one time to get you moving......which would do more damage... I'm sure you would choose the push over the slug hammer... but, that is what happens inside your engine as you pull that little red handle back... remember the hammer when you do... but, that is not all that is happening... you also cut back the lubercation and cooling of the exhaust valve and it seat... as well as other things that get more technical such as harmonic vibration.. crank spring.. etc... take my word for it... cruse at 75% or less.. and try to keep the EGT around 75-125... with 125 being perfered... with todays fuels
Another area that I avocate is the cruse climb and decent...if possiable... and after the gear is up and the flaps are up... and all... close the cowel flaps and let the plane go to 125 mph or so... while climbing... it will stay cooler... and make better miles per gallon of gas used...
So to give you a definable answer to your settings... and others... their is no hard and fast number... each plane, engine etc... while made the same... all have their differances... and will all use a little different fuel setting... and will consume at different rated... the varables are pilot tech, engine life, enviroment, fuel, and a host of other things that are happening at the time of the flight...
hope this helps... fly safe... G.M>

Fluctuations in RPM

gmas replied
We need some more info... like year... turbo or not... etc.... Please expand your question.... any other things that happen to the engine while this is going on... like one or both engines... temp, OP, etc...

Richard Francis added
Plane is a 1976 337G normally aspirated.> MP pressure was stable Fuel flow was stable Normal indications on the engine analyzer RPMs varied from 2500 to 1500 (more or less) Seemed as if both engines were running out of fuel at the same time. Happenned after a climb from sea level to 8000' just as I began to level off. Lasted for about 10sec then returned to normal with no further problems. Fuel contamination? Let me know what you think. Thanks

Richard... I've been there... and believe me it gets interesting... real fast... Ok... here is what I want you to check out first... the fuel tank vents... Have you had the fuel fuller caps changed and complied with the AD... check here ... the filler cap vent... check for bugs plugging... or rubber flapper hardening... also when was the last time you checked the Fuel vent valves...out in the tips... you have to remove the wing tip to access the valve... the shop/parts manual show you that they are able to be disassembled and how to do it... If you are not a A/P mechanic.. You have to have one do it for you...... and they do get plugged... remove, clean and replace... you might want to check to see that all these things are clear and not obstructed..... as well as the vent line that goes to the rear of the tip... look for bugs pluging it up.... common ... disconnect and check for restrictions... to vent air and are causing a vacuum in the fuel system in the tank... as you go up and burn off the fuel... which will cause a fuel starvation problem... Then when you level off and the fuel flow goes down... the tanks can recover... and the engine recovers.

Next I want you or your mechanic to look at the fuel pumps... and check the litle 1/64 inch hole that vents the low pressure diaphram... it is located out at the end of the pump in the casting... next to the adjustment bolt and lock nut... I (my personal airplane) had a problem end up in the club shop where... the fwd engine would quit in flight... hitting the boost pumps would bring it back but.... it led to your anxiety attack... with all kind of things going through my mind... about what was wrong... come to find out it was the witness paint that was put acorss the locking nut to fuel pump body...by one of the young mechanics... and plugged the little vent hole.... which we have found is very important.. not to plug or restrict... now if you don't think that was hard to find... my fuel pressures went all over the place... but mostly the engine would faulter... and exibit the same symptoms your did... Check these things and let me know if one of them are your grimlin.... I think you will find it something simple like what is mentioned above.... If you still have problems ... write.. Good hunting.. G.M> 337 club.

Gear Horn Sounding Off

G.M>337Skymasters Club replied
Paul... yes it probably was the gear horn switch on one of the throttle... if you pull the throttle back on each engine with the gear up.... one at a time sometimes you can get the horn to go back off because the switch was just dirty... other times we have seen the wire break off...at the switch also... it should have gone off once you had the gear lowered... if it didn't then you have something else wrong with the dual warning system... hope this helps.. fly safe.. G.M.

Paul Sharp said further
It did go off when I lowered the gear again for landing. So I think it's just one of the switches that has a broken wire or the switch has disintigrated. The wires seemed rather loose on the rear one when I pulled the cowling and looked at them. At least that should be a minor repair; put the last one on myself (front engine) after O/H in November of last year and had it signed off by the mechanics. Thanks for your input.

GMAS>337Skymasters Club replied again
Yep that is probably what it is them... the micro switch that cessna used when they made it is a common one that you can get from a good electronics part store like Newark Electronics.. I don't have the part no.. but you want the one that is computer grade... i.e has gold contact.. inside.. but, in a pinch you can use the regular one... the last time we bought some the were around 1.95 us a piece... The switch body is all the same.. it is the spring and roller length that you have to match... and are not interchangable ... to repair a wire... well I would say that would kinda be a ability thing... where electronic knowledge would be the key factor.. so if you are a ham radio or electronics buff.. I could not see how it would require a A&P to sign it of.. but it is a repair.. and may be one of those grey areas... that the FAA would call... I am sure that if you did it under the watchfull eye of and A&P it would suffice... just don't overtighten those little screws and nuts.. that hold the swich n place... and crack the plastic.. like I do somethimes... they have a torque rating of an ant-arm-lenght.. and just finding them little buggars..sometimes can be frustrating ... I finish it off with a little loc tight.. or gliptol on the threads to keep the nuts from comming loose... (I think they are 6-60 size because they could not make them any smaller just to frustrate us 300 lb gralla sized mechanics) so be careful and not loose them n the engine... hope this helps.. fly safe.. G.M>

Guages

Greg Zimmerman replied
I had a similar problem with my front engine. All guages were normal but had a noticable vibration, which could be felt stongest on the front engine prop control. The cylinder barrel had broken away about 1/2 inch from the case and the piston was still able to go up and down freely but the barrel of the cylinder was vibrating against the prop cable. I shut the engine down thinking I had a problem with the prop and was very suprised when I removed the cowling. I was lucky to be flying a Skymaster as I was over the Everglades at the time.

Gmas also replied
It is quite normal to have the engine windmill.. and still pull MP, RPM and Fuel flow... you are correct in looking next at the EGT... to see if the engine is still runing... the egt will tell you if its producing heat... othewise the prop govnor will hold the rpm of the engine... and the pistons going up and down will pull a vacuum... or MP... the fuel flow is the fuel pump and regulators.. and again if the engine is turning over you will get fuel flow... But.....

You should have noticed one little thing.. the plane slows down about half speed... good clue that something is wrong... in the power department...

Ice

Paul Sharp replied
Well, I have to add my 3 cents worth here (already added my "guess" 2 cents, so this makes it a nickel).

I respect the opinions of all who don't fly in "known" ice, and I'm perfectly aware that the 337 isn't certified for flight in known icing. But mine has boots, including one on the horizontal stabilizer (GMAS mentioned the "elevator" and I don't know if he was equating that to the stabilizer or was technically to the moving "elevator" itself). I also have a hot prop (front), but no heated windshield.

In any event, I consider the de-icing equipmetn as an escape route mechanism.

Nevertheless, since the FAA's people are bent on following the "reduce risk or lawsuits as much as you can" route the rest of the nation seems to follow in our ridiculous liability environment (America is the only major nation in the world where one idiot can sue another and get away without paying for the other's legal costs if he loses and that has to be one of the dumbest things known to mankind - but...) - they mention a "chance of icing" in almost any forecast where there are clouds.

So for the practical IFR pilot, you must weigh the risks and decide whether you want to stay on the ground all those times they "mention" ice in forecasts. For myself, if there are known reports FROM PILOTS that there is serious ice where I want to go, then I cancel the flight. Or if the forecast is for "heavy" ice or freezing rain then I wait for another day.

But I've encountered ice in my plane, and I've used the boots a few times to clear it. I live and fly in mountainous terrain with lots of winter weather. At the first sign of ice I request another altitude (usually higher unless I know warmer air is below) and fly out of it. If it ever happened to hit me heavily enough that I couldn't wait on ATC to climb or descend then I'd declare an emergency and do so anyway (or do a 180) while they figured out their end of things. I tend to fly conservatively enough that I don't expect that to ever happen, but I have the plan in place if needed.

The boots and hot prop have done what I needed them to do:

1 - Allow me to change altitude or escape clouds - to get to where ice wan't.

2 - Keep me flying to get up to altitude through a verical ice layer.

3 - Keep me safe while descending through an icing layer in order to make an approach and land.

I'm not willing to stay on the ground every time the "I" word, reckoned scientifically possible, is mentioned by weather forecasters on the slim chance that I might, just might, someday hit ice that was greater than I could deal with while climbing, descending or whatever. As I said I try to be reasonable and conservative with my weather calls, and wouldn't hesitate to do a 180 . And if I didn't have the deice equipment then it would be another story so far as I'm concerned.

My experience with it is that the equipment works for light and moderate icing. That's why I bought a plane with that stuff on it.

Jeffrey A. Gleason replied
Thank you for adding your two cents - it is worth plenty more than that and I appreciate your sharing it.

Regards,
Jeff

Jose L. Ichaso replied

I posted last year the Skymaster Safety Record 1983-1999, and recall just one fatal accident due adverse weather-icing.

James Grant replied
Dear Sir,
I would have to say that the low total times are simply because the Skymaster has for the most part been an owner flown private aircraft.Whilst many have seen use for aerial survey,patrol and the like,most have been someones pride and joy perhaps flying 50 to 100 hrs a year.My 336 for example has only 1450 TT which equates to less than 39 hours per year.
As for known problems,there are of course ares of concern as with any aircraft.However parts for the Skymaster are still readily available from the parts houses ,and also from Cessna if you can stomach the prices!
Known ice certification is a lot more than just installing wing and tail deice boots.The first thing to ming is a heated or alcohol deiced wind shield.the skymaster is but one of the cessna aircraft from the 210 up that has deice installed but is not approved for flight into known ice.I don't know about you,but I fly a light Jet with boots for a living,and if I even have to think about popping the boots to loose ice then I need to be somewhere else.If I had the choice I would loose the boots but keep the heated windshields so I could see the runway!
Good luck

Regards

James

Jerry De Santis replied
I have a 1975 P337G equipped with boots and a heated windshield clip on plate. I fly between 150 to 300 hours per year both business and personal. I can ensure you the skymaster handles ice very well. It can carry quite a load. I agree you don't want to intentionally fly into icing conditions. But if it happens, I can state first hand boots are great to have. I am based in Michigan and I have been in to many MIC approaches where I picked up 1/2 to 3/4 of an inch of ice in less than a minute. I will not own another aircraft unless it is equipped with boots.
Jerry

SkyKing replied
Hey Jeffrey,

Suggest you read the entire history of the CLT Skymaster, including the P-version at this website:
http://www.superskyrocket.com/pages/History/history_1_1.htm

This information, compiled by William D. Thompson, one of the engineers and test pilots at Cessna, will give you a moment of pause to BOTH of your questions.

SkyKing

Jeffrey A. Gleason replied
I read the article last night. Doesn't seem very clear to me (although I will re-read).

Can you elaborate on how you interpret the article?!

Thanks,
Jeff

SkyKing replied
Jeff,

I've been flying since 1968... and with the wealth of information that's been put forth, not only in this particular thread, but elsewhere on this website, as to the attributes and qualities of the 337 series, I'm of the impression that you're beating a 'dead horse'. If 'low total time' of the 337 series airplanes bothers you, coupled with the fact the 337 is not certificated for flight into known icing conditions, why not move on?

Seems you should be studying ownership of a T310, as it more closely resembles parameters that are not bothersome to you. Consider: (1) the T310's have higher numbers of total hours; (2) they are certificated for known ice; and (3) if you ever have an engine-out problem, the spare engine will take you to the scene of the accident. But in the meantime, you can play 'macho' pilot and shed ice like the big boys.

As has been eloquently stated time and again here, the 337 is NOT for everybody... but for those of us with discriminating taste buds who own and fly them, there's really no other airplane out there that even comes close to the performance, handling and flight characteristics, ice or no ice. End of story.

JR
SkyKing

Jeffrey A. Gleason replied
Perhaps you didn't have an opportunity to read my original post? (copy below). Gee whiz I was only asking some straight forward questions not about things that are "bothersome" to me. On the contrary, I am quite intrigued by the Skymaster based on its unique combination of qualities. That's why I'm here in the first place.

I am merely puzzled by the low total time most of them have and wondered if there was any specific reason - anyone considering buying a plane and noticing that most of them on the market seem to have relatively low total time for their age might wonder if there is some reason (perhaps costly or unsafe) as to why they are not flown more.

I am also puzzled, not bothered, simply puzzled and curious as to why they were never certified for known ice. Is it too much to be surprised and curious as to why a manufacturer would make and market a pressurized twin and not have it certified for known ice?! Seems odd, doesn't it. Honest question.

I'm basically simply trying to rule out any big nasties that might stop me from buying one and my two points of inquiry are to see if there are glaring issues regarding putting time on them or unintentionally picking up ice in them that may modify my current desire to own one.

Can't be any more innocent than that! People seem to think they need to jump on me when that's all I'm looking for. Yikes, I mean I'm a nice guy and everything, just curious. I don't think my original post seemed negative or indicated these things were bothersome to me.

Its nice to have this forum where people experienced with a specific plane can share their interests and knowledge - at least I'm greatful for it because there are not too many places one would find a such a wonderful knowledge base on a relatively rare bird such as the Skymaster.

My simple, original post read:

"Hi Folks,

1. Looking into Pressurized Skymasters and noticed that, for their age, they almost all seem to have LOW total times - is there some hidden high operating cost factor or some life-limited part(s) that keep people from putting hours on these birds?

2. Any idea why the Skymasters were never certified for Known Ice - seems like a pretty limiting factor (technically) when Cessna was trying to sell these - a pressurized plane without known icing?! Was it due to the plane not being able to handle ice well, or the expense of certification, or what? Anyone know?

Thanks,
Jeff"

Paul Sharp replied
A heated windshield plate was available for Skymasters, but most seemed to be ordered without one, even if they were ordered with hot props and boots.

I've heard, and can't verify for sure whether or not it's true, that the problem was when trying to get the certification, after they flew around long enough, there was so much tail feather area hanging out there that they just couldn't put "boots" on enough of it to continually clear all the surface area. For the usual encounters, I agree with Jerry's posting - mine seems to shed the ice just fine, and if I get in the stuff long enough to worry about having it build up on other areas of the tail then I've screwed up somewhere already. I've used my boots and hot props and they work fine for the only kind of "ice" flying I intend to do: an escape route to get out of it right away.

GMAS 337Skymasters Club replied
Iceing... Hmmmm like playing russan rollete... with a
simi auto hand gun....

I know that most of the pilots don't understand but, iceing is the worst thing behind thunderstorms that a pilot can go into... I used to fly C-130's and 141's in the service... my job was to go look into big... big storms out in the alantic... we flew in and around hurricans... and other sever weather... and you can believe me that if the wx officer said their was a chance of iceing... I would start looking for a new way around ...
I have seen it go from nothing to about a foot thick in less than a min... and with all the extra hp that the 130 had... their were many times that we were coming up short... flying into known iceing is bad practice.. and the FAA does a good job of letting you know they don't like it either... under the FAR careless and rec. flight... rule... you could lose your license.. but, the rule is their for a reason... to keep you and others on the ground from getting killed... or hurt...
I wish I could find the letter of thanks that was written by a grateful skymaster pilot who iced up... Seems we heard his weak signal...mayday... and assisted his blind flying... we gave him altitudes and directions to a small field ... seems he was flying back from flordia and hit the cold air... forcast known iceing conditions... started to ice up... and within mins.. he was asking center for help... but they couldn't hear him... too much ice... after he reported that his pitot and static ports iced over... his first contact .. we showed he headed out to sea... and he said that he was a instrument pilot with lots of hours... and thinking equiped with deice boots and hot shield.. he was golden... He found out that .... having a encounter with known iceing conditions... seems the old boy was way over his head... he couldn't see and about the time we got to his location and got a visual on him....the fwd engine quit... the plane was so iced up that you could not see inside it.. the windows were all iced... and the color of the plane was just plane white... It looked like one big ice cube... I had all the de-ice stuff on line and we too were picking up inches per min... in the 130... but, we had radar.. and knew the coast... but, this guy was going down.. and needed a place to land ... now... luckly... the nav found a small field 5 miles away...and we escorted them to it... he had to open the storm window to see... and we helped with altitude information... till he touched down and landed. In his letter he said that it took them 30 min to get the door open as it was frozen shut... and when they took the fwd cowl off they found the whole engine was frozen up " like one big block of ice... and big chunks were falling off the wing about 6 inches thick... he didn't have to meet his maker.. he repented on the spot...
on the spot.. and gave thanks.. for the rear engine and the position of the airfield...and us... because he would have gone down in the swamplands... and the aligators would have gotten him...

After giving a testomonal to the FAA... they promptly removed his license.. which his wife... which was a passenger that day..... gladly made him give up... thus hanging up his spurs...

Now the moral of this story is ... if you believe the forcasters... and you can for sure know where the ice is... and can predict how much you will get.. then more power to you... go fly in the ice... but, most of us don't have a crystal ball.. and the suth sayers hot line is not going to be much help... before you go...
Don't temp mother nature... she will put your butt on the ground for sure... so stay out of ice... no matter what plane you have.. you don't have enough stuff to handle it...... and I don't fly for the weather service anymore .. so don't expect any help from me to bail you out... yep your going down in the swamp.. and the aligators will get ya.. be they FAA or weather guessers... either way your dead... watch out... and as the kings say... stay out of the trees... add to it.. and ice... Cessna didn't certify the skymaster for flying into known iceing for a reason... can you say wrongful death and liability.... smile... G.M

Jeffrey A. Gleason replied
Thank you for your detailed and "cautioning" response.

My question is not seeking to determine if it is wise to fly into known or forecast icing conditions, but rather why the Skymaster was never certified for flight into known icing. I believe what you wrote whole heartedly. Ice is not something to mess around with. However, your theory as to why Cessna did not have the Skymaster certified for flight into known icing, though empassioned, seems unsubstantiated.

There are lots of small planes, many with reputations for being much less able to handle ice than Skymaster, that are certified for flight into known icing, INCLUDING Cessnas. Cessna has had designs before and after the Skymaster certified for known ice. And from the earlier feeedback and other readings, it does sound as though the Skymaster handles ice at least as well as other, "known ice" certified planes, so I suspect there must be other reasons why they never sought approval - and this is the information I seek.

Regards,
Jeff Gleason

GMAS 337Skymasters Club replied
While some want a more detailed explanation... as to why Cessna didn't certify the plane for known iceing... other than liability issues... we submit the following... from discussions with Cliff Ives ... then cessnas head rep...
Cessna aircraft in the late years were getting hit with suits left and righ... stupid ego pilots... but, only cessna would know the real reason for not going after certification... we believe the following was their MO..
First was money... Second.. if you look at the planes CG and load balance it is very narrow... it can carry a large load.. but, it has to keep it between the engines.. as you have read from others here on the web ... when it is snowing... the skymaster sitting on the ground
is susceptable to shifting aft resulting in it setting its ass on the ground... Now it seems logical that in flight the wings are going to ice up.. but, if you look at the elevator section and rudders... you will see they do not have any de-ice boots on them.. just a rubber strip... wonder why...
we believe that they would have too hard a time trying to get everything in balance with the boots... after all if the elevator boot shucked the ice then the cg would shift forward... and if the wings shucked theirs then the cg would shift aft... imagine the pilot trying to fly inst in that conditions... (early skymasters did in fact have boots on the elevator... for the military but, they were removed on later ones)
The next problem they would have is the ice coming off the wings and getting into the props... hitting it would be like launching a large rock by the back propeller... and if it hit the elevator... it could do some serious damage... not to mention the ice coming off of the rear prop being slung into the boom section... putting dents into it would structurally cause failure...
I could go on.. and if you thought a little on the subject with some knowledge of how the plane operates... you could also come up with a few more reasons that one would not want to use this plane for flight into known iceing... basicly it was just not set up to do it... small efficent engines with low heat output... etc.. and as we said before in our other response... you don't want to anyway... unless you have a death wish...
with any airplane... currently known to man... most of the time pilots go above the iceing conditions... or below them... and some of the unlucky few that we read about... try to go through it...thinking they are golden... empassioned or not it is substantiated ... by the records of dead pilots attempts... this plane is no different... the bottom line... don't fly into known iceing conditions... with this plane.. the rest of the reason is just acadmic... G.M

Jeffrey A. Gleason replied
I appreciate all the input.

Are there any people on the board that have flown the Skymaster in ice and lived to tell about it - or do they all die? Guess I'm hoping to get some testimonials on how it does with different amounts of ice.

I'm not planning to kill myself, but I've been up in other small planes and picked-up ice and lived to tell about it. I'm no Evil Kinevil (spelling?) - I don't have a death wish - just want to know.

While the "ice hitting the booms" idea seems plausible, ice coming off the wings and props and hitting the elevator would be a concern in essentially all aircraft, so that point seems moot here.

By the way, hope I'm not coming across as a jerk, I just really want to understand this with clear, objective, concrete information - sometimes there is a tendancy for hangar tales and assumptions to overshadow reality. I've been researching the Skymaster for quite some time and these two issues (low time airframes and non-know-icing) have been nagging me. I've been in aviation since 1982 (man, where did those years go?!) as a commercial pilot and flight instructor, and having a technical background I am always trying to find out the nitty gritty.

It would be poor piloting to intentionally fly into known icing or to disregard planning to avoid all icing. But small planes fly in icing all the time and they don't all crash, burn and die.

Is their solid, concrete empirical (or otherwise) evidence that the Skymaster is more deadly than all other small planes in icing condition? Or would you all say it was equally deadly?

Regards,
Jeff

Jim Rainer replied
I think if you want a testimonial about how much ice a Skymaster can carry, read GMAS' article about when he was flying a C-130 and helped a 337 land even after the entire airframe was iced up and the front engine had quit!

I'm based in Tennessee and rarely encounter ice in my normal flying (I won't go if it is forecast, unless there is a good 3,000 feet of warm air above the ground to shed ice by coming down.) However, I have encountered ice in both booted and non-booted 337's and it's never been a problem. My windshield has shed ice just before landing several times so I haven't landed with the side window open yet (but I have in other twins.)

I believe the 337 can carry ice as well as any of the small twins.

Jeffrey A. Gleason replied
Jim, thank you for the info.

I understand the moral of GMAS' story (don't get into icing or you'll crash and maybe die), but it could also could be looked at as a tribute to how much ice a Skymaster actually can carry and still not drop out of the sky! (although it sounds like he would have crashed from lack of visibility without the help of the C-130 crew). But, either the pilot was completely negligent in his duties to avoid/escape from icing or he encountered the shear force of mother nature with no warning whatsoever. He may or may not have been stupid, but their is no arguing he was lucky!

Thank you again for sharing your experiences.

Jeff

GMAS 337Skymasters Club replied
Jeff.... no in a side by side... the ice is blown off the wings by the prop blast... in the skymaster you have the rear prop behind the hull and main wing... and if you go look at most you will see that the rear prop really takes a beating from little items like screws and nuts that come loose... but, what I saw happen one time was a big chunk of ice break off and hit the prop in the rear... happened to be a P with de-ice boots.. and the boots kicked the ice ... which was clear ice in this case... it came over the top of the hull and hit the back prop... with such a force that it sent a shudder through the hull... and the engine set up a vibration... so much so that the pilot had to shut it down... not good in iceing conditions... and when we landed... checking the rear engine.. we found that both the rear motor mounts were broke... at the engine... now these were not rubber .. they were the cast metal parts... that hold on to the engine...
I think the rear prop has a lot to do with cessna not certifying the plane for known iceing... and as I said before... the result of the ice on this planes hitting the prop.. sent pieces of rock hard ice denting the elevator.... like someone had taken a shotgun to it... the rear prop had accelerated the ice to the rear... but, I would be more conserned with ice forming on the spinner of the rear engine and then getting slung out the sides hitting the boom... now again if you look at the plane.. cessna has a stiffner plate in line with the prop blades on each boom... I think this it to take care of any....oppps ice that comes off... but, I doubt if it would last long if you contenued pounding it with lots of ice...

Now lets look at the fwd engine... here we find the engine really doesn't have much protection... and I could see how with the air intakes location.. how it could cause the engine to ice up and quit... them little 360's just don't have much heat as they are a more efficent engine... and unless you put some sort of blockage at the air intake... they just won't get warm enough... but, also with them big holes for air intake.. and the design.. iceing would be able to plug 'em up.. with no chance of getting any heat up to them to help keep them clear... The rear engine is different and reports that I have read seem to suggest that the air intake does indeed ice closed... just like the one we saw over on the east coat that we helped... but, the engine kept running.. it was the fwd engine that I noticed had stopped... and again the plane looked like one big ice cube... its a wonder that the guy could even make the alerons and elevator work.. and I think some of his bobbling around was because he was using a tech to try and keep the control surfaces from freezing up... I used the same methode on even the larger planes... but, where our old boy was having problems seemed to be in the weight department... when we got to him.. the gear was down... as he had put it down knowing that the ice would freeze the doors closed.. just like his pass door... when he tried to get out... everything freezes togeather... but, I didn't see any flaps go down when he made his approch to the runway... and at that time I think we started to run into freezing rain... as I remember my front windshield was frozen over and we had lots of heat going... He didn't have any radio antennas as they broke off with the ice which he thought was what vibrated at first... His ADF wire to the rear was broken and trailing behind the rudder flapping in the breeze... so the ice must have broken that off too... and with no antennas he probably wasn't getting far with his radio... I could tell he was just a little conserned... but, it was his comment about "I'm going down... cant maintain altitude"... was his words... I asked if he had tried to start the forward engine .. and his reply was that it would not turn over... the prop looked like a white feather on both sides with the ice on it... and I am sure if he had started it it would have flung ice all over... he went on to say that their were two people on board and gave us the particulars... and at that time I truly believed he though he was not going to make it... but, your tax dollars were well spent.. and the training that my crew had.. went to work... each knowing what they needed to do to help him out... and I assured him that he was going to get back to land... no promass on the landing though... I said quietly to myself... when the nav said.. I got a small field 5 miles away ... I asked if he could turn to a new heading.. and he replied that he only had his compass left... as both vacuum pumps had quit.. probably froze and sheared the couplers... so we did it the old fashion way... like the GCA people did... and we got him on a heading stright for the runway... the nav quickly computed his rate of decent per mile... and we stayed off his right side... my hardest job was trying to stay in the air... as we were at the bottom of our flying speed and with the ice building up ... it was a challenge... to stay with him... but, he was doing ... about I think ... 140 kts.. I had every lifting device out and heater runing that the 130 had.... and had the other crew members watching the ice build up... anyway.. the rest is history... as I said before...

Sure the skymaster would be able to take on iceing conditions... but, again as I said... its not rated for it so... I won't do it...with mine... and my ops on the subject is ... hit ice.. make a 180 an get the heck back out of it... and if they forcast it and and I cant get above it.. I ain't going... smile...

I hope that this gives you a better picture of the why and hows of it... otherwise.. the p is a good plane.. and with the ability to get up to 20kft.. you would go over most of the heavy ice... and with the long legs that the skymaster has.. you should be able to find a field somewhere that is out of the "heavy stuff"....
its a good plane... but, it does have its flaws... and this is one of them... because the engine is in the rear...

Oh ya as to the low times... well after you have been their 2 or 3 times... you don't want to go again... smile... so you only go for short flights... as for commercial use.. its not what I would call passenger frendly... setting between the two engines... but, then again I sit up frount... so I don't have any problems... smile.... its more of a utility plane than a show plane... besides like some people say.. it has two tails... ya I answer ... the other one is a spare... just like the two engines... the one in the trunk is a spare too.... smile... G.M

Jeffrey A. Gleason replied
Excellent post - this is the kind of info I was looking for. Thank you soooo much.

Regards,
Jeff

GMAS 337Skymasters Club replied
Iceing... Hmmmm like playing russan rollete... with a
simi auto hand gun....

I know that most of the pilots don't understand but, iceing is the worst thing behind thunderstorms that a pilot can go into... I used to fly C-130's and 141's in the service... my job was to go look into big... big storms out in the alantic... we flew in and around hurricans... and other sever weather... and you can believe me that if the wx officer said their was a chance of iceing... I would start looking for a new way around ...
I have seen it go from nothing to about a foot thick in less than a min... and with all the extra hp that the 130 had... their were many times that we were coming up short... flying into known iceing is bad practice.. and the FAA does a good job of letting you know they don't like it either... under the FAR careless and rec. flight... rule... you could lose your license.. but, the rule is their for a reason... to keep you and others on the ground from getting killed... or hurt...
I wish I could find the letter of thanks that was written by a grateful skymaster pilot who iced up... Seems we heard his weak signal...mayday... and assisted his blind flying... we gave him altitudes and directions to a small field ... seems he was flying back from flordia and hit the cold air... forcast known iceing conditions... started to ice up... and within mins.. he was asking center for help... but they couldn't hear him... too much ice... after he reported that his pitot and static ports iced over... his first contact .. we showed he headed out to sea... and he said that he was a instrument pilot with lots of hours... and thinking equiped with deice boots and hot shield.. he was golden... He found out that .... having a encounter with known iceing conditions... seems the old boy was way over his head... he couldn't see and about the time we got to his location and got a visual on him....the fwd engine quit... the plane was so iced up that you could not see inside it.. the windows were all iced... and the color of the plane was just plane white... It looked like one big ice cube... I had all the de-ice stuff on line and we too were picking up inches per min... in the 130... but, we had radar.. and knew the coast... but, this guy was going down.. and needed a place to land ... now... luckly... the nav found a small field 5 miles away...and we escorted them to it... he had to open the storm window to see... and we helped with altitude information... till he touched down and landed. In his letter he said that it took them 30 min to get the door open as it was frozen shut... and when they took the fwd cowl off they found the whole engine was frozen up " like one big block of ice... and big chunks were falling off the wing about 6 inches thick... he didn't have to meet his maker.. he repented on the spot...
on the spot.. and gave thanks.. for the rear engine and the position of the airfield...and us... because he would have gone down in the swamplands... and the aligators would have gotten him...

After giving a testomonal to the FAA... they promptly removed his license.. which his wife... which was a passenger that day..... gladly made him give up... thus hanging up his spurs...

Now the moral of this story is ... if you believe the forcasters... and you can for sure know where the ice is... and can predict how much you will get.. then more power to you... go fly in the ice... but, most of us don't have a crystal ball.. and the suth sayers hot line is not going to be much help... before you go...
Don't temp mother nature... she will put your butt on the ground for sure... so stay out of ice... no matter what plane you have.. you don't have enough stuff to handle it...... and I don't fly for the weather service anymore .. so don't expect any help from me to bail you out... yep your going down in the swamp.. and the aligators will get ya.. be they FAA or weather guessers... either way your dead... watch out... and as the kings say... stay out of the trees... add to it.. and ice... Cessna didn't certify the skymaster for flying into known iceing for a reason... can you say wrongful death and liability.... smile... G.M

Mike Martin replied
Well said.

It's an interesting note that if you talk to pilots who have flown big airplanes certified for known ice you will fine that most have a very healthy respect for ice and avoid it like the plague in small airplanes. I've been flying corportate jets for over twenty years, all certified for known ice, and my adrenelin still pumps when I have to spend any time in the icing environment.

I fly my P337 for recreation and to get me to a vacation home. I take my family and friends on these trips. I won't fly this airplane in an icing environment. I am not a life saving doctor. I don't carry organs for transplant. World peace will not come to an end if I cancel a trip. Those that survive thier fly careers, like G.M., usually have sgae advice for those who are just starting. I hope they will listen so they can give sage advice when they get older.

Have fun. Be careful

Mike

Multi-Time

J.R. Prukop replied
James,

I was involved in the airline "mill" during 1990-1991 with a 135 commuter operation flying Beech 1300's, 1900's and Brazilia's. It is apparent to me that the most important skill is NOT whether your multi-engine experience comes from a Piper Apache, a Cessna 310 or a Skymaster, or whatever ... that's not the issue to be considered. Utlimately, they're going to train you in their equipment the way they want you to fly it, i.e., procedure. The most important skill is a GOOD SCAN and keeping a complex airplane, be it a 310 or a 337, going where it's supposed to be going, with the outcome never in question, i.e., planning ahead. I was fortunate to have about 125 hours of King Air turboprop time when I was hired on at United Express (Mesa Airlines/Farmington, NM), and the balance of my experience at the time I was hired on in 1990 was 10-hours of B737 sim-time through a friend who happened to be a senior check airman and sim-instructor at a 121-carrier, a few hours in a Piper Seminole for the ATP and maybe about 6-hours in a 310. I wouldn't get too twisted about worrying about which airplane to purchase in order to get multi-time in to satisfy the whims of the airlines. I would just make certain I was current and met the requirements of FAR 61.57. Personally, I would purchase an airplane that satisfy's your own particualr safety requirements, with a minimum of AD notes, and an airplane that is to YOUR liking. The 337 or P337 are logicaly choices from the perspective of losing an engine, and has one tough airframe to boot. You'll find a minimum of AD notes on this superbly designed and handling machine, and the pressurized version (which we have) makes an excellent cross-country IFR machine. It's extremely quiet considering the engine locations as compared to say the 310 or Piper equivalents, and the fuel burn is great considering horsepower and speed. What's probably the nicest feature of this airplane is that the cabin will maintain sea-level up to about 8,000 feet, and a 10,000 foot cabin when the airplane's at 20,000 feet -- and NO masks! Incidentally, the P337 will make a 340 run-for-the-money. Browse the Cessna 340 listings for price and then the P337's ... and consider the P337 will do the same things with only about a 10-knot difference! With all things being considered, the 337 series has the most bang for the buck. Hope this helps your dilemma!

Power settings

gmas replied
Hmmmmm... well that is kinda right... but, leaves a lot to be discussed... First of all when you make a manafold reduction it reduces the power ... less power... less heat... also by reducing the RPM... again makes less power... and actually brings the engines to 75 per cent at sea level... (top of the green) You are right when you say it reduces the amount of fuel... as it does bring the controller back on the lean side... so also does the power drop...leaving it ric h.. It has been my experance with the IO-360 that you can't overheat it by running the power... instead I have found that the cooling air (plennum) pressure is the problem. Most of the baffeling has been cooked so badly and never replaced that it leaks... also the sheet metal baffeling is not the best either... by closing up the holes... even a 1/8 inch one... and sealing around the baffeling... with silicone... replaceing the flexiable baffeling seals... fixing or replacing the cracked and missing metal parts... you will see a big differance in the cooling of the engine. I have seen club members rear engines go from overheating to running cool... just by these changes... Another big bug is the manafold pressure gage... When was the last time it was checked/calbrated.... Also reading its paralax view... becomes a problem... I found some members ran the rear engine harder... thinking the needles are matched... not so... We had the Cont. mfgr rep... come and give a talk on this at one of our meetings.... I will see if I can get him to come to a future meeting again... if enough want to hear about this subject... G.M> 337 Skymasters

Steve then added
Less power less heat. I agree. It would be nice to hear from an engineering standpoint which is more effective in reducing temps, full throttle and full rich or reduced power which as I understand automatically resets the fuel air ratio closer to peak EGT. Try both and check your EGT.

gmas replied again
Having checked the Cont. Eng manual... it appears that The BMP vs. fuel flow in BTU's contrubute to the overall heat of the engine... I found that some other interesting items also appeared when I was doing some calculations... first of all it appears that the engine's RPM has a lot to do with internal heat. I.e. the amout of hp used internally increases when RPM increases... Let me explane... if the engine is turning over 2300 rpm it has a internal hp consumption of around 11 hp.. (746 watts = 1 hp.) But if we increase the RPM to around 2800 it goes to 32 hp. If you multiply the numbers you will see that the heat is increased internally... with no gain... also if the engine uses 0.5 lbs/hp/hr... we can see that the fuel increases just to overcome the internal requirements... increases... Ok... now lets get real technical... The engine was designed to produce max hp... contenious... it was certified such. This is the max Hp/RPM... 28 inches at 2800 rpm.. to produce 210 hp. The amount of heat that is produced to make this HP is taken into consideration and it was cessnas responsibliity to insure amount of air flow... that cont. specified required to provide the necessar cooling... This is what we call plentum pressuere/flow. No matter what MP/RPM you run the engine at... with that amount of air flow the engine will operate within the normal range of temp's. So... what they are saying in the manual... make sure that you have the air flow... and the engine will not over heat... no matter what you run it at... rember it was certified at max power... all day... Now we can't deal with perfect conditions all the time so we baby our engines... and run them at reduced settings and think we are running them cooler... or we run them at full power and a rich condition thinking we are running them cooler... Oh what to do.... well again we go to the engine manual... and guess what... we get the less fuel... less heat... true if we pull them back we lose the full power enrichment... to keep from burning up the engine.... but, Hey... wait a second...you say... look at the EGT... It goes up when we pull back the MP... Yep... it does... but, I ask you does the EGT indicate the heat inside the cyc... or the temp of the escaping gasses... Looking at the Egt... we find this instrument to be only reliative in reading... and will only tell us the temp of the exhaust gasses... run the MP up to full throttle... and grab the mixture control... pull it back... it goes to peak... and then what happens... yep it start going down... but, watch the cyc head temp... it goes up...and up... and up... why? well when the mixture goes past rich...and starts leaning out... the heat of exhaust becomes less but increases in the cyc.. the oxygen becomes geater... (fuel/air mixture) now what burns hotter a oxygen supported flame or a fuel flame... but... you say the EGT decreases... yep it does... because of the time it takes the fuel to burn... it burns hotter (oxygen rich) but, less time... and goes out before the exhaust valve opens.... cooler exhaust... ie the heat is contained within the cyc... and efficency is at maximum... but, it brings us dangeriously close to something else... too... pre ignitions... and we all know what happens then... parts melt... Hmmmmmm... Ok so what is the answer... well if we keep the mix ratio around 11-13:1 we have max power and the engine runs well... but, it produces x units of heat... If on the other hand we reduce the amount of power required... we reduce the fuel required and thus less heat produced... while holding the mixture range. Thus we get x units less heat by doing this... but, if we want even less heat... we can reduce the RPM (to a point) and by reducing the internal power consumption...(see above) .... less heat.... What... you say is all this gibberish... Ok let me put it to you this way... do I generate more heat with the engine running or the engine off...Hmmmm... cant figure it out... well let me know which one you get burned by touching .... engine that not running or one that is running..... thus less fuel (with the mixutre correct... 12:1 or 125 deg on the rich side of peak EGT) manafold pressuer and RPM reduced... or I do with everything at the firewall.... I'll run mine at reduced power... if possiable... I usually try and keep it around 65 per cent power... (RPM/ MP) and guess what at 100 deg rich of peak on the EGT... I get 40 Lbs fuel/ Per Hr..per engine and my engines run in the middle of the green...(18/2300) and still get 160mph... Hmmmmmm great plane huh.. Don't go strictly by EGT... cyc temp and EGt are related but.... seperate... Then again... each of us fly our own way... and have our own way of flying. A good referance is Peter Garason's book "Long Distance Flying" and the Naval Airman's handbook of aeronatics operation. I have seen several good books writen on the subject overseas also. But, the most impressive and factual is the Cont. Engine Overhaul manual. This has the curves to show all the pramaters for operation of the engine.... but, no egt readings. G.M>

gmas then added
And just when you thought it was safe to go out into the air again... I spent the weekend with a great group of mechanics... FAA and Reps... and camped out at the Cont eng reps booth.... I found out some interesting things about the engine... and will make up another letter... if you are interested... But, he did say one thing that I disagree with still but, will pass along anyway... He said that you C A N cool the engine with just the fuel only... of course it would run real rich... and smoke a lot but, that was one of the test that they did during certification... He said that inriching it .... will cool it at any power setting. Now I am confused... I will have to go back to peter Garrison and talk with him again and cite Lorrens' testomoney... Hmmmmmmmm.... G.M>

Rear Prop on soft fields

Rory Chin-A-Kwie replied
thanks Burt for your info

do you also have an adress for me
where they sell this prop guard

rory

Burt Benson replied
You can order "Prop Guard" from Goulet Aircraft Supply. 1137 Sanford St., Winnipeg, Manitoba R3E 3A1, Canada Phone: (204)783-8512 Fax: (204)783-3302

Burt

rick bell added
I operate off a 1600' dirt/sand strip in baja.
the front prop takes 80% of the damage. mr. benson
suggestion on prop guards is great, i use them;
however the front last only a 1/3 of the back's.
if you have a hard runup area your results are much
better, i don't so i can't hold the brakes and spool
up before release (to much damage occurs)

Robertson STOL / Mountain top Landings

Jim Rainer replied
I had a Robertson STOL kit on a C-T210 and found the aelirons stiff but responsive. I would not use your autopilot at all with any flaps down - I think it is approved with only normal (not STOL) approach flaps if at all. In the situation you described with updrafts and downdrafts -- you need to have full control yourself. The 337 has light aeliron inputs so I believe it's the STOl kit just as it was on my 210. This is a Robertson characteristic I believe. They are great kits but they degrade the wonderful feel of the 337 w/o them. Also it will drop like a brick if power is lost or cut with full flaps out.

Rudder movement with gear retraction

GM @337 Club... replied
You have a small problem .... and no it is not normal ... First make sure your feet are not on the rudders when you swing the gear... by being on the rudders... I mean depressing one of them.... Second... make sure you have the rudder trim set correctly... as this will put pressure on the noise gear too... If the trim is flying correctly... and you have the gear pushing on the rudder pedals... your rudders may be out of specs... and may need to be adjusted...Is your ball on the T&B centered... or are you flying one wing low... and a little x-controlled... While were on this subject... you may want to check the brackets that the pully's are on... espically under the dash back by the firewall... in back of the rudder pedals on the pilot side... check for bracket cracking.. which can be seen by pressing on the rudder pedals and looking for movement at the same time... As to the noise gear... you need to have your mechanic check the gear rollers and track that it runs in... they should be greased at annual time... The shop manual.... shows what to use and where to put it... YOu do have a shop and parts manual for your plane... it is just as important as the POH... we encourage all of our members to have a set... we felt that every plane should have come with a set ... and passed on to the new owner... just like the POH... They are a gold mine of information and one of the better manuals that cessna put out... almost like a military T.O. (tech Order) manuals for the services... it covers everything... The shop manual to work on it... and the parts manual to show you every nut, bolt and screw in the airplane... and the changes in parts through the years... hope this helps... G.M> 337 club.

Blake added
I have the same problem with my skymaster (1975 C337G). The maintenance people couldn't figure it out at the last inspection. I have to crank in right rudder trim after the gear goes up (it can be felt about 3 seconds after the gear motor starts running) and take the trim out after the gear is selected down. At higher speed in the descent more rudder trim is needed. The gear was cycled during maintenance to see if a door was remaining open but that isn't it.

Gerd Wengler added
I had the same problem with my 1976 337G. It cannot be the doors since I had a door removal kit.

Dave Zavoina replied
I ran into a problem like that on a 69 "D" model and assertained that it was in the nose gear steering bungee, that goes from the rudder bar to the nose gear, and after talking to the owner it was decided to ignore this pesky problem due to the expense and it is is a small inconvience that only occurs during the retract cycle.

Skydiving

Dave Zavoina replied
The military O-2 Pilots Manual has the proceedure for bailout, however, unless the sucker is on fire or has a structural failure, I'd prefer to ride her in. The rear engine is mounted about 20 inches higher than the front, and I've dropped parachute parcels to boats at sea and haven't had a prop strike yet, but the door wasn't removed either. On a 182 jump plane the door is below the wing, not foreward of it, and with the door removed, it could affect the airflow at the wing root, with disastrous results. Now, getting a jumper to exit with a 210 horsepower cuisinart is another story......

gmas also added
Hi... to answer your question... yes their have been people jump/skydive out of the mixmaster... About 4 years back I had a person write the club and ask how hard it would be to do... No having a 75 with the air stair door.. ment that if anyone opened the door in flight it surely would break off or else damage the inside of the wing where it came up against. But, knowing cessna and the extensive testing that they did.. I figured that they had just about flown the bird in every configuration... including one flap full down and the other retracted.. they said it was an interesting ride but, flew under control... anyway... I fired off a letter to them and asked if the mixmaster cold be flown with the door off.. and surprise.. they said it could but, that I should restrict my speed to under 130 Kt. I passed the infor along and sure enough they said it flew great... a little breezy but fine.. later on I see that the group "Brothers to the Rescue" who also have a web site.. flew on tv with their door off... and were throwing rafts...radio's, food and water out of it... Now as to jumping from the plane... I asked a good friend of mine who is nuts (jumps from perfictly good planes for the movies) .. stunt doubble. What he thought of it... the reply I got was a picture of him jumping from a mixmaster.... He said that with the door off (1978) and the bottom one closed... it was easy to fall out of... he said he turned sideways in the seat and fell out backwards... the speed that they were doing was around 100 kts... On his second jump.. he said that he dove sideways out the door when the pilot made a right turn... at about 45 deg... roll... as he said... nothing to it... we passed his info along.. but, I learned a long time ago in AF training... that they only way I would leave a plane... if it came apart... or was on fire.... and even then I would have my resevations as to if the parachute would work... (smile) If you are woried about the back prop... as he said.. feather it out and your outa their...and home free... Hope this helps...

David Mattix
I'm glad I found this site because I am in th process of purchasing a 337 for business and personal travel but since I am an active skydiver I was entriqued with the thiught of jumping the plane as well. Seems to me the feather the rear prop may be the best bet or a pronounced side slip at jump time. I'd like more info from any sources. Thanks

Speed Flarings

Frank Buono replied
the speed fairings that I believe you are refering to appear to be the ones produced in Nashville tenn. he advertises in trade a plane in the 337 cessna section. he list boom fairings ,wing tips and other items which to me look rather ugly but if they perform as well as reported they may be well worth the price and ugliness. good luck Frank

Unimproved runways

Burt Benson replied
I guess the answer to your question is "Depends". It depends on the load and density altitude and whether there are trees at the ends of the strips. The 337 handles unimproved strips very well. In fact, it is a marvelous bush airplane. I operate regularly out of 2500 - 3500 foot gravel strips in northern Canada. Two thousand feet is about the shortest field I have had the 337 into. I would not feel comfortable with 1600 feet especially in the summer with a near gross weight load and/or obstacles at the ends. I don't have the Horton or Robertson STOL kits. I'm sure they would help quite a bit.

bill grandstaff replied
Thanks for the reply. The 337 that i am looking at is a " Riley" conversion with a Robertson STOL kit. yhe runway in Mexico that i go into is 1900 ft no trees and sea level with loose gravel. I own a Maule and a Baron, The maule does great but i would not take my Baron in there. I was looking for to trade the baron for a 337.

Bill

Frank Benvin replied
There was a charter company operating out of a 1400ft strip at sea
level on the west coast of Vancouer Island, Canada. My father flew in and out of it in our 1967 337.
The trip from home to the strip was 30 minutes. He would take himself and one other person and make sure he had a small fuel load.

Jose L. Ichaso replied

I use very often a 1300 ft airstrip of compacted sand. It´s in a flat island at sea level, and tempetature usually is between 78°F and 90°F all year round. I have use this airstrip with five adults total on board, and the plane performs very well before reaching any edge of the airstrip. Mine is a 337D with Horton Stol. I can send you some pictures of the airstrip.

Jim Rainer replied
My only comment is that my normally aspirated 337G handles "short" very well but not "soft." It's not nearly as sprightly on grass (especially tall - 4" to 6")or loose sand. I've never been on gravel. But as all the others have said, "it depends" on a whole lot of factors. My plane holds 148 gallons of usable fuel (7 hours worth!)and four folks and still be legal but I wouldn't attempt to use the strip you describe for that mission. By myself or maybe with one other and no more than 1/2 fuel, I would do it occasionally - except in one of our Memphis, TN summers - 100 degress on the runway. Hot days affect performance as much as anythting in my 337. On a cold winter day, it would be breeze. You didn't mention wind or ground caused turbulence - these can mess you up big time if you are holding a little extra speed for gusts. I had a 1966 "C" Braon and it was a wonderful short field plane. None of them will perform on 1900' within the book "accerlerate-stop" parameters. I'd stick with the mall.

Gravel poses a special problem with 337's because the front prop will throw gravel into the rear prop and I have had some deep gouges on the back of my rear prop - not enough to have to replace the blade but close. This can be avoided to some extent by accelerating with the rear engone first then slowly bring up the front engine as speed builds - but on a short, marginal strip - this won't work either.

SkyKing replied
Bill,

In the early 1970's before we got pavement on our sea-level airstrip, which at that time was 1300 ft grass with 50 to 75' scrub trees off the west end a ways, we regularly hosted Cessna "Open Houses" and invited the Skyways Zone Reps for Cessna to bring up new planes to demo. One of the first Skymasters in and out of our short field was a brand new 1974 P337 - stock from the factory - N60S (which is now in Chile and 'For Sale' by the way). Would you believe - four big necked, 6'-2" swollen bellied Cessna sales reps packed into that airplane with briefcases and loads of literature and full tanks - not a problem with the 337!

The Cessna POH for 20 degrees C at Sea-level shows a ground roll of 985' at full gross on a dry, level runway. Add 15% for the grass and you get 1132'. The demo pilot knew his airplane well and as I recall from the several times they came in and out, they were off in about 1000' with a full load. HOWEVER, 'IF' there had been a problem with a powerplant or any reason necessitating an aborted takeoff, that's where things get sticky, because the accelerate-stop distance would have ruined their day. At full gross weight, lifting off at 63 KIAS, on a 20 C day, the accelerate-stop distance would be 2745'. So, as others have commented... it 'depends' on a number of factors.

Our P337 has Robertson/STOL... and at 500' to 1000' elevation airstrips (paved) and using the recommended STOL procedure at full gross weight, which is 2/3 flaps, rotating at 44 KIAS, our ground run is about 500' with no wind. With lighter loads, say 4200#, and a 10-Knot wind, the ground run is about 350'. So, if you're looking to enhance what the Skymaster already has to offer in the performance arena, my advice would be to find one with the Robertson/STOL.

Good luck...

Jim Hickam replied
I believe a major cause of rear prop damage is the wheels kicking up rocks when operating on unimproved fields. Does anyone else think this is possible ?

Jim Rainer replied
Very much so. Even on improved payment that has rocks on it.

GMAS 337Skymasters Club replied
Yep.. the nose wheel is the main reason for the rear prop getting messed up... but, some of the other stuff is kicked up by the mains too and it does seem that once you get underway.. getting the nose up off the ground will then allow you to bring the fwd engine up to power... saving its prop from small stones and sand...
We have watched them land in water or wet runways should I say... and the spray seems to come from the rear mains more to the inside where the rear prop hits it... the nose tire also put a line into the center area.. so I would think on sand you would have the same problem... as it would have the same disturbance... G.M

Stephen Fogarty replied
I recall seeing a C-336 passing through Anchorage with a Tibbets-Herre nose fork that allows the installation of an 8.50 nosewheel and GarAero main wheels that were probably at least twenty inches. This is a fairly common set up for 206's that do off airport work but is also faily spendy. This would, of course reduce the single engine rate of climb but allows the aircraft to be used on a multitude of surfaces that you would otherwise never consider landing on.

Vne for Skymasters

Jason Friesen said
200 knots

Ian Clapp replied
Thanks, Jason. I would have thought it's a bit higher since the Riley conversions are said to do 225 kt TAS (but perhaps that's at altitude - IAS is probably about 165 kts at 20,000 feet.)

Window open, flying with

David Wartofsky replied I once inquired this regarding my T337D of Cessna. Their response was, "We're not sure..." Apparently the window is "similar" to a C210 window which is good to 192 knots, but...

GMAs337Skymasters Club said
You can take the window completely off and it get real breezy... or keep it closed... if you try to open it up... it will hit the wing and break off... in flight.. and could damage the wing... sorry.. but, if you try it let us know if cessna factory is right... on the later ones with the air stair door... we have taken the top off and flown it that way.. but, you have to keep the speed down as it get real windy inside... and if you need to clean out the plane... this works better than a vacuum... almost to the point where it will suck the numbers right off the instruments... we had to wear goggles just to see... headsets to keep your hearing...and looked like we came from space... with leathers on... and we all went single file to the water fountain because our lips were dry.... seems the stuck to our teeth... now that is windy... huh... smile...

Mike Zinn added
In my 79 P337 I regularly fly with the window open, but its just the little side vent window that opens inward. Its great for ventilating the plane quick when flying unpressurized and letting some of the heat out, but its also noisy. Years ago I put my hand out there a little bit just to see what it was like, and almost had my arm torn off.

Dick Dale also added
yes, I did the same thing, I stuck my fingers out the little side window and thought they fell off, ha no more on that one... but it is real neat to fly with the little side window open and it does take out all the heat in the cockpit.. I 2nd that one... dick

GMAs337Skymasters Club then said
Side window vent.... the little window on the pilots side does offer a great way to vent the cabin... however it takes your hand to re-direct the air into the cabin and as you can read it does cause pain but.... their is a guy who came by trying to sell a plastic window repalcement... that has a scoop on it with the ability to shut it off... we tried one out and it worked great... helps the pilot keep his cool in the summer and pulls out air in the winter...and fitted right into the same space as the window is... so that if you don't like it you can remove it and put the window back in .... and takes only min to install.... If your interested in it.. I will see if he still makes them... g.M.

Mike Zinn added
I vaguely remember that product, and I think it was for the non-pressurized 337. I may be wrong. But I don't need to put my hand out to get major ventilation boost from the opened window. It just adds lots of noise. I especially enjoy it when touring at low airspeed.

Dave Zavoina said
Eat you heart out guys, the Air force was fortunate enough to supply us O-2 guys with windows that open 90 degrees with a wind deflector mounted on the door foreward of it to keep the wind out. We also have two nifty fresh air vents on the lower instrument panels, and two openable side windows under the wings for ventilation.

GMAs337Skymasters Club added
Ya.. and I suppose your going to say...a bunch of 7.62mm bullet holes to let the water drain out the bottom tooo.... huh... (smile)

Ed Coffman asked
which windows on the 0-2 opened 90 degrees? The big side windows by the pilot and copilot seats?

Dave Zavoina replied
The door window opens 90 degrees, the window by the pilot seat is oversized, that is that it curls up over the fuselage radius behind the windshield, and it is also the emergency exit. The door window also has a crank with a clutch to crank open the window the full amount. This was an observation aircraft and it made things easier to photgraph from

J.L. Ichaso added
You can buy a new, original O-2 door with flight openable window for about $1600 at RT Aerospace, Tel. 305-688-5803/305-688-5811, Anyone can checkout the RT Aerospace web page at http://www.gate.net/~rtaero/ and see by yourself not only the O2A Door (There is a photo catalog), but the many modifications this company has STC for our Skymasters. You can also could contac them by their e-mail:rtaero@gate.net

Zero Thrust

Michael Hayes replied
On page 3-8 of the Cessena 337 owners manual there is a chart for zero thrust Propeller RPM With the front engine at 2800 RPM and at 2500' rear engine is now set at 2320 RPM, at 5000' set at 2410 RPM, at 7500' set RPM at 2510 With the rear engine at 2800 RPM and at 2500' front egine is now set at 1930 RPM, at 5000' set at 2010 RPM, at 7500" set at 2090 RPM
Simualate single - engine procedures can also be practiced by setting the propeller RPM of an idling engine at zero thrust as shown in this Figure.
Remember an unfeather propeller causes a lot of drag.
Good luck, Michael Hayes

Rufus Crowe replied
We have a 1967 337B and the owners manual has no such chart on page 3-8. There is no mention, whatsoever, in the manual about simulated single engine out power settings....??
Appreciate the information, Thanks Again!

Michael Hayes then pointed out
The information I sent you is out on my manual for a 1970 model E- 337. The airplanes are for the most part unchanged that information should work in your model.