336 Owners

[Richard]

I'm in the North West United States. I'm looking at a few 336s for sale here in the states. All about the same condition. I own a T337 now, but having some issues with it that might take a few years to sort out. Looking at a simple 336 to taxi me and my family around. I've also got several STCd parts that are just sitting on a self that need a home.

The things I've heard is the vibration and noise is greater in the rear engine of a 336. I don't see how a properly balanced fan would cause any additional vibration. I've also heard that the structure on a 336 isn't as strong? Just looking for some happy 336 owners (besides the ones selling theirs) what the consensus is on ownership?

[David Dixon]

Well I suppose it's a bit difficult comparing the two since I've not owned a 337. The obvious differences are:
The 336 is slower, The aspect is not as good (horizon is high) less things to go wrong with the fixed undercarriage, rear engine appears to run hotter. noise or vibration is no problem for us,
A new rear prop was hard to find.
Make sure your props are current, we got stuck with the old out of date props that didn't have the red dye. These are illegal and it was an expensive exercise.
I wouldn't be buying a plane of this vintage without thoroughly checking for internal corrosion. Does the rear cowl operate? these cowl motors are known to give trouble. If it works that is a plus. Ours is always open as I havent sourced a rear cowl motor. In the event of a rear engine failure, the rear cowl if stuck open can cause drag. One important thing to do before any purchase is to thoroughly check the rear exhaust pipes. They have been known to fail which can cause a fire. This happened to me and the previous owner. (we now have had new stainless pipes made with minimum welding) We feel that we have overcome the problem by a thorough check of all welds at least every 50 hrs. Check if the exhaust brackets are free to move also.
Are all the seals around the engine in place? these are for the upper air to be forced through the oil cooler. There are to be no gaps for the air to escape
Test fly the plane on a hot day and monitor the rear oil temp.
If the aircraft is highly maintained and all is up to date and the price is right, go for it. We love our 336 (the only one operating in Australia). There is a fellow 336 owner in the US who is expecting to fly his 336 to Australia and is negotiating long range tanks.
I'll leave you with one thought, you're best to look at a well maintained 336 than a clapped out 337. Any more questions please feel free to ask
Regards
David

[Richard]

Some sage advice there, thank you. I love the comment “a well maintained 336 than a clapped out 337”. Just so happens one of the 336s have recently new exhaust systems and less than 1550 hours on the entire airframe (can be good or bad).

Just curious, what type of fuel burn can I expect at a given cruise? What to you flight plan for? Ever had to re-balance the rear engine fan? What is a “normal” rear engine head and oil temp that you see?

[David Dixon]

1550 hrs amazing. I'd still check the corrosion factor. The airframe is strong enough I'd think, I've never heard of one bending, though you do have to be careful of something they call 'Boom Bounce" which can weaken the main spar, but this is in any Skymaster not just the 336. Boom bounce is caused by the controls not adjusted to correct tension and the product of this is an oscillation rocking feeling when the plane is trimmed.
Fuel burn, say at 3500 to 4500 ft I plan for 80 lts per hour on average and this takes in account taxi. You'll have to work that out in gallons for you, but I find on my fuel flow that when I lean it out, it shows on average just under 11 gallons per hour per engine. anything less than that the egt rises above the accepted.
My speed with the rear cowl open is about 130 knt mph but that increases when I have my wheel farings on which they are not at the moment. My mate in Washington State says he has 10 knts on me.
No I haven't had to balance the rear fan, never thought of it. I don't get vibrations, but it all helps I suppose.
The rear head temp also runs hotter I'm not in front of my instruments at the moment, but I'd guess at about close to 350 for the front head and closer to 400 on the rear on a hot day. Oil pressure around 50.
Re Oil temps, under 200 on a cool day for the front and over 200 on the rear. For me, anything out of the red on the rear oil is good at the moment, I'm sure I have a faulty wire between the transducer and the guage as I've replace EVERYTHING except that.
It's really annoying. My plane is fairly highly maintained and I've just had it painted. New pic to be posted when I get the wheel fairings on.
Anything else feel free to ask.
David