Center Thrust in GA (Why not?)

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LJS1993

Line Up and Wait
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LJ Savala
Why didn't center thrust catch on in general aviation? As some of you know I love the looks and idea behind Cessna's attempt at center thrust with the 337. However why didn't it catch on?
 
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Probably noise and performance mixed with a not spectacular record because it was often bought and operated by less than competent pilots.
 
I don't know...too unconventional for people to accept? Just look at the Cardinal...it is definitely a better plane than the 172, but which one is still being made today?

I sure wish there were thousands of Rutan Defiants around instead of Apaches.
 
SteveR said:
I don't know...too unconventional for people to accept? Just look at the Cardinal...it is definitely a better plane than the 172, but which one is still being made today?

I sure wish there were thousands of Rutan Defiants around instead of Apaches.
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I quite like my Apache. :(
 
SteveR said:
I'm not knocking the Apache, but I bet you'd enjoy the Defiant's speed on the same engines, not to mention the much more simple emergency procedures. :)
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I have nothing against the Defiant, but I have yet to see one that wasn't a half cocked piece of junk.
 
Around the time the C-336 came out, the French gave it a go, as well:

moynet_360-4.jpg
 
It failed because it has all the disadvantages of a twin -- it's not twice as fast, nor does it carry twice as much, or fly twice as high, but it costs twice as much to operate -- plus it has all the quirks of centerline thrust -- like cooling issues for the back engine.
 
I like the 337 however it is loud,needs constant maint.and uses a good bit of fuel.like the engine out procedures and love the looks.
 
Ehhh Jay - it's more like 3 times the price to keep around.
OTOH, going across these inland seas around here, especially on a soggy, nasty night, the sound of the second engine s u c k i n g fuel, is comforting . :D
 
Jeff, I am really sorry you posted that picture.
Now that is just plain ugly.
Think I'm gonna have nightmares.
 
Centerline thrust probably would have caught on if not for the Cessna 337 being such a god awful implementation of the idea. Folks probably figured if Cessna couldn't pull it off, nobody could.
 
Jay Honeck said:
It failed because it has all the disadvantages of a twin -- it's not twice as fast, nor does it carry twice as much, or fly twice as high, but it costs twice as much to operate
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Along the lines of what Jay said it didn't catch on because of the cost disadvantage of a twin combined with the increased noise and less baggage space compared to traditional twins.

The issues that come up with the 337 about maintenance arise more from owners who didn't take care of their planes early on moreso than design problems I believe.
 
Fearless Tower said:
Along the lines of what Jay said it didn't catch on because of the cost disadvantage of a twin combined with the increased noise and less baggage space compared to traditional twins.

The issues that come up with the 337 about maintenance arise more from owners who didn't take care of their planes early on moreso than design problems I believe.
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This I will buy.

Thing is being a high wing makes it the only NA twin no my radar
 
Don't own one myself when I was looking at twins I purchased a Travelair that fit my budget.did get a few hours in 337 s also I fly with pilot who owns one frequently.
 
Estimates:

O-2 models delivered to the military: 544

337's delivered : 1961

I guess building and selling 2500 of a design is a miserable failure. :rolleyes:


Now if you look at the multitude of manufacturers and start-ups that have been in and out of bankruptcy the last 50 years, I'd say the 337 and Cessna was fairly successful.
 
bnt83 said:
Estimates:

O-2 models delivered to the military: 544

337's delivered : 1961

I guess building and selling 2500 of a design is a miserable failure. :rolleyes:


Now if you look at the multitude of manufacturers and start-ups that have been in and out of bankruptcy the last 50 years, I'd say the 337 and Cessna was fairly successful.
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I'd rock one, and suspect that in the next 5 odd years the odds of it aren't bad.
 
bnt83 said:
Estimates:

O-2 models delivered to the military: 544

337's delivered : 1961

I guess building and selling 2500 of a design is a miserable failure. :rolleyes:


Now if you look at the multitude of manufacturers and start-ups that have been in and out of bankruptcy the last 50 years, I'd say the 337 and Cessna was fairly successful.
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Sadly, by today's standards, the 337 was a stunning sales success.

In its era, however, it was seen as a flop.
 
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By today's standards, the 337s sales per year would now cover the entire industry's sales per year.
 
Jay Honeck said:
In its era, however, it was seen as a flop.
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By whom ?

There are about 1/2 as many 337s built as there are Senecas, Beech sold about 3000 55 Series Barons. Not sure where you would get from that it was a 'flop' ?
 
As with the C-177, the 337 was a good airplane that had to overcome a not-quite-ready-for-prime-time opening act (the C-336). What it couldn't overcome, however, was that it was expensive to build.

In 1967 Cessna test-flew a similar but smaller 4-seat CLT twin, the Model 327, intended to compete head-on with the Twin Comanche. It had cantilever, laminar-airfoil wings borrowed from the C-210G, and according to photos I've seen, it was prettier than the C-337. It proved underpowered with 160 hp engines, so 180 hp O-360s were used for later flights.

According to Bill Thompson's book, the project was dropped because Cessna realized that the cost of construction would make the airplane too expensive to compete with the PA-30.
 
Pilawt said:
Around the time the C-336 came out, the French gave it a go, as well:

moynet_360-4.jpg
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Who was it that coined the rule for aircraft identification that I've seen in Klyde Morris? "If it's weird, it's British. If it's ugly it's French. If it's weird and ugly it's Russian.". The thing is definitely French. :-)
 
They're all down in Miami (Tamiami & Opa-Locka ) like all the '57 Chevys are in Cuba .
 
SteveR said:
I don't know...too unconventional for people to accept? Just look at the Cardinal...it is definitely a better plane than the 172, but which one is still being made today?
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Never buy a Cessna that ends in 7.
:)
 
From what I've read about the 336/337, it failed to live up to the promise of being a safer airplane than the traditional twin. This is largely in part because it suffers from low power engines, so single engine performance is poor. I have read that the Riley Super Skyrocket conversion, with two TIO-520s on it, it performs as it should.

I think if Cessna had upped the HP with a 338 model or something, they may have sold even more and perhaps inspired competitors to get into center line thrust. Sadly, we'll never really know how good, or bad center line thrust is in GA because the whole concept seems to be damned by the experience with one aircraft. There aren't enough Defiants, or A500s out there to make a realistic assessment of how they would fare in the greater GA population.

What I really would like to see is somebody pick up Rutan's Boomerang design make it a bit more practical and run with it. IMO, it is the best light twin ever built.
 
By potential buyers.

During the time it was produced, Cessna could sell a good-size bunch of almost anything--for a while.


weilke said:
By whom ?

There are about 1/2 as many 337s built as there are Senecas, Beech sold about 3000 55 Series Barons. Not sure where you would get from that it was a 'flop' ?
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Basically, it's a performance hit that just can't be overcome. The rear engine is in the wake of the fuselage, and the wing, and influenced by the twin booms. It's also in the stream of the front engine where the air is already being blow backward at some rather hi rate of speed, so to propel if further in already dirty air is not at all efficient.
 
docmirror said:
Basically, it's a performance hit that just can't be overcome. The rear engine is in the wake of the fuselage, and the wing, and influenced by the twin booms.
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That must not be too big a problem, because the C-336/337 performs better OEI on the rear engine than on the front engine. So much so that it inspired Cessna to investigate a twin-boom single-engine pusher design in the C-150 category, to see if better performance could be coaxed from a low-power engine. Performance was okay, but it too had issues with noise, vibration, rear-engine cooling and crashworthiness, control system friction, overall weight and projected construction cost.
 
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