… so once again is pure fabrication.
Nothing of what I wrote here is fabrication.
No time for details now, just a few examples from a quick google search.
- Rear engine cooling: There are companies specialising is retrofitting better cooling for the rear engine, e.g.: http://www.cessnaskymaster.com/rear-engine-cooling.html
Never heard of anything similar for a Seneca…
Or a quote from a pilot “Tricky in hot weather sometimes, had the rear engine go to feather on me during takeoff because the oil temp got too hot.” I never heard or read anything similar about any other aeroplane.
And for the rest, here is a good source for pros and cons: http://www.aopa.org/News-and-Video/All-News/1993/July/1/Cessna-337-Skymaster
- Cooling: Cooling of the rear engine is difficult and inefficient and therefore produces much more drag than a front mounted engine.
Sure that Burt Rutan will not agree with such statement on the drag part. The long EZ and derivatives are proof that a pusher configuration could be a low drag aircraft!
Actually, his desings benefit from small fuselages more than from pusher configurations…
Real world for the un sexy, but reliable workhorse Seneca 1 (with Lycomings, C337 boasted Contis), is 140 KTAS on 60 to 70 litres per hour. The C337 with slightly bigger engines may best this with good ANR headsets, but the Seneca 1 provides a spacious cabin with similar useful load. The C337 does better on SE ceiling, but it’s accident rate was similar to other conventional twins.
I think the Seneca may have been easier to spanner, hence enjoying better commercial success as a workhorse. A few global charter operations started out on humble Seneca 1s.
what_next wrote:
No time for details now, just a few examples from a quick google search.
Is that all you have to offer ?
No Google search anecdotes will substitute for first-hand experience, both on the controls and in the work-shop.
his desings benefit from small fuselages more than from…. [insert your favourite aerodynamic improvement]
You could say that about almost every light GA aircraft.
Those that go fast for a given fuel flow are simply very small planes.
And if you don’t go for certification and jack up Vs by say 10kt, and settle for concessions like insufficient rudder authority to counter the torque (true for all the really fast warbirds) at whatever Vs might be, the improvement is dramatic.
Actually, Michael, the efficiency of a cooling system can be decribed in terms of heat transport, or in terms of drag generated. The cooling of the rear engine may work very fine and still generate more cooling drag than on a classic pull configuration. Given the higher total energy of the incoming airflow, it can be reasoned that this is indeed the case, provided both cooling systems are designed equally well. But there are indeed cooling mods for pull configurations by LoPresti.
The transport efficiency can indeed be defined as kinetic energy in cruise over energy used, what would factor in different engines, too, and evaluate the aircraft as a complete system eta_t = (1/2*m*v²)/(LHV*dm_fuel/dt).
Michael,
I also wondered about this airplane a lot, especcially the P version. I noticed that on one of the P&F trips to the US, there were 3 337’s I believe and they seemed to be more than adequate for the task.
What I have HEARD though is that they could not be registered in Switzerland for noise reasons, nor can they fly to a lot of European airports for that reason. So do you know from the planes you maintain what the actual noise certification of this airplane really is? I also notice that most of them ar N-Reg, so can they actually fly under EASA reg?
Re performance, I found this on AOPA:
Count on optimum cruise speeds for the normally aspirated models in the 165-knot range at 5,000 feet, burning 23 gallons per hour total. That’s a bit slower and a bit thirstier than conventional twins packing a pair of 180-hp engines. Cruise speeds of the T337 show a best of 190 knots at 25,000 feet, burning 22 gph total, while a 1980 P337 (225 hp each engine) tops out at 204 knots, using 26.6 gph at 20,000 feet
For the P model, AOPA lists the following performance data:
Cruise speed/endurance w/45-min rsv, std fuel (fuel consumption, total)
@ 75% power, best economy, 10,000 ft 186 kt/4.9 hr (26.3 gph/158 pph)
@ 75% power, best economy, 20,000 ft 205 kt/4.8 hr (26.5 gph/159 pph) =0.129 USG/NM
@ 65% power, best economy, 10,000 ft 177 kt/5.6 hr (23.3 gph/140 pph)
@ 65% power, best economy, 20,000 ft 192 kt/5.6 hr (23.3 gph/140 pph) =0.121 USG/NM
Which would translate into a range of between 950 and 1050 NM with 148 USG useable at 20’000 ft.
In my database, the Seneca II has the following values:
@75% power at 10’000 ft 175 kt and 22 GPH = 0.125 USG/NM
@65% power at 10’000 ft 165 kt and 20 GPH = 0.121 USG/NM
That translates into a range of around 750-850 NM with 123 USG useable at 10’000 ft.
From there, I would think the P337 is a good 25 kts faster with similar fuel per NM but better range due to larger tanks.
What would be a show stopper in Europe will be excessive noise. And the AOPA summary sais that this airplane has a take off RPM of 2800 RPM, which could well mean a quite hefty noise. .
Mooney_Driver wrote:
can they actually fly under EASA reg
I clearly remember OO-VDA and there must have been several more on the Belgian register. Long before EASA, mind you.
Mooney_Driver wrote:
From there, I would think the P337 is a good 25 kts faster with similar fuel per NM
If you compare apples and oranges…
It’s somewhat unfair to compare the F100 figures of the Seneca with the F200 figures of the 337
