The Cessna C335/C337 has a poor reputation today, and many can be bought very cheaply. I heard of two reasons for its loss of popularity: difficult access for maintenance, especially to the rear engine, and lots of noise.
The access must be a solvable by clever design, I should think; OTOH noise is an inherent issue with a pusher prop.
Why is nobody offering a similar design, powered by a couple of Rotaxes? Could make a damn good tourer, affordable to acquire and to operate. The known issues do not seem to be insurmountable.
Jan_Olieslagers wrote:
lots of noise
I can confirm that. When one was landing at my homebase, I thought an aircraft was taking off.
However the noise Level should be significantly reduced with Rotax. Same applies for cooling issues due to water cooled cylinder heads.
I maintain two 337s for a couple of friends.
IMHO, it is grossly under rated and a very capable aircraft.
The access for maintenance is also over-stated, although not as good as a typical light twin, it’s not that bad either.
It is noisier in the cabin than other twins but about the same as most singles and nothing that a god pair of ANR head-sets can take care of.
I’ve flown them and they handle almost exactly like a Cessna Centurion. Engine outs are non-events and some operators will even shut down an engine when loitering.
In todays market they seem to sell for about the same as an older Seneca or a Twin Comanche.
In your list of disadvantages, you forget a few things:
- Efficiency: The rear prop is spinning inside an totally non-uniform air mass that is heavily disturbed by the flow over the wing, around the fuselage and additionally through the front prop. This rear engine will under some unfavorable conditions produce less than half thrust of what it could achieve in undisturbed air.
- Cooling: Cooling of the rear engine is difficult and inefficient and therefore produces much more drag than a front mounted engine.
- Then there are mass&balance issues which require the overall layout of wing and empennage to be far from optimum, the twin-boom tail in itself has a massive drag penalty of it’s own.
- The whole thing is doubly dangerous for getting in and out of while the engines are turning, because there is danger lurking from both ends. Especially in a panic situation (e.g. fire/smoke) the rear engine poses a great threat to escaping passengers.
There is always a good reason, when after 112 years of powered flight, a certain aircraft layout has resulted in just one single model which ever reached the market…
what_next wrote:
- Efficiency: The rear prop is spinning inside an totally non-uniform air mass that is heavily disturbed by the flow over the wing, around the fuselage and additionally through the front prop. This rear engine will under some unfavorable conditions produce less than half thrust of what it could achieve in undisturbed air.- Cooling: Cooling of the rear engine is difficult and inefficient and therefore produces much more drag than a front mounted engine.
- Then there are mass&balance issues which require the overall layout of wing and empennage to be far from optimum, the twin-boom tail in itself has a massive drag penalty of it’s own.
- The whole thing is doubly dangerous for getting in and out of while the engines are turning, because there is danger lurking from both ends. Especially in a panic situation (e.g. fire/smoke) the rear engine poses a great threat to escaping passengers.
Bull-pucky. You need to do your homework.
- The N -1 performance of the 337 is better than a similarly powered and MTOW aircraft the Seneca 2 and 3 , in fact it has the best engine-out performance of any piston-powered light twin,.so whatever “supposed” loss in efficiency is your invention.
- The cooling of the rear engine is perfectly acceptable as long as the baffles are properly maintained. The problem here is that many are NOT properly maintained …
- No W&B problem with the 337, in fact, once again it is more favorable than a similar twin .
- That’s never been a problem , so once again is pure fabrication.
what_next wrote:
There is always a good reason, when a certain aircraft layout has resulted in just one single model which ever reached the market…
However this assumption, which I strongly support, remains…..
It’s the same as with the C400 and SR22: even though it completely failed on the market, it is actually the best design out there!
Does anybody have POH figures for cruise speed at a given level for a given fuel flow for both the 337 and let’s say a Seneca I or II? Efficiency is always the same on those Lycontosauri so speed vs fuel flow for a comparable airplane is a very good data point.
boscomantico wrote:
It’s the same as with the C400 and SR22: even though it completely failed on the market, it is actually the best design out there!
It would be with CAPS, but I don’t want to start a new discussion on this topic again – I think we (almost) all had enough of this 
The pusher prop used to have a better SE RoC, so there is some principle of flight reason why it is more efficient.
I believe it was a much loved improvement over the L-19 Bird Dog, and my tube and fabric L18C, in its 0-2 Forward Air Controller guise in Viet Nam.
http://waltshiel.com/wp-content/uploads/2015/05/o-2.jpg
I had also heard it was less truck like in handling than the C210, or perhaps should diplomatically say had less positive static stability in handling.
