Simviation Forum - couple of questions

Jun 7^th, 2010 at 6:46pm

yancovitch Offline
Colonel
effortless effort
born montreal, live vancouver

Gender:
Posts: 1897

wonder how a plane shaped like, for example, a killer wale, (with oversized fins), would fly....

also....even in ww-1 there were pushers and tractors...why did the tractors win?...seems to me that pushers might be more efficient.....

intel i7 950.....asus p6t delux v2....asus gtx 285......raptor 150g...raptor300g (fsx)......liquid cooled cpu cooler.....6gb corsair 1600-777........windows 7......antec 900 case.....

Back to top

IP Logged

Reply #1 - Jun 7^th, 2010 at 9:02pm

SaultFresh Offline
Colonel
Flight Instructor, CYKZ
Woodbridge, Ontario

Gender:
Posts: 134

Well, with regards to the killer whale question. A lot of it has to do with lift. If those "fins" are designed in the right way, then they can create sufficient lift to get this supposed "killer whale" in the air. As for your question on tractors and pushers. Well, I'm not a history buff or anything, and I certainly wasn't aware of their being pushers in WW1, but all that aside, my thought would be that a pusher would be easier to shoot out of the sky in classic dog-fight style. Where the attacker lines up with the tail of the enemy and takes them down from behind. If the engine is at the rear of the plane, it's probably easier to take it out. Again, no idea if that's the right answer to your question, someone out there probably knows more about it, but that's my educated guess.

Back to top

IP Logged

Reply #2 - Jun 8^th, 2010 at 1:01am

Splinter562 Offline
Colonel
Tampa, FL

Gender:
Posts: 217

For pull vs. push:

Pusher configurations are stilled used today, but they typically not a popular choice. Both configurations have their advantages and drawbacks. The tractor configuration tends to be more suitable in general, so unless there is a specific reason to do so, that is usually the configuration that gets used.

Here are a few of the common problems with the pusher configuration that I'm aware of:

C.G. - Usually, a foward-mounted engine will help offset the weight of the tail structure. With a pusher, you tend to have aft C.G issues.
Tail Structure - A single-engine pusher prevents you from having a typical tail configuration, so you need to have twin booms to put the tails on.
Airflow - A tractor prop gets nice clean air to work with. A pusher gets trashier air and is partially obscured by the fuselage.
FOD (Debris) - Anything that falls off the airplane is going to go through the prop.

As always, Wikipedia has lots to say on the subject:
http://en.wikipedia.org/wiki/Pusher_configuration

Back to top

IP Logged

Reply #3 - Jun 8^th, 2010 at 7:00am

Fozzer Offline
Colonel
An elderly FS 2004 addict!
Hereford. England. EGBS.

Posts: 24861

Of course...

You could have the best of both Worlds... Wink

...

The lovely Cessna 337 Skymaster.... Kiss

....!

Push + Pull!

Paul.... Cool

....!

Dell Dimension 5000 BTX Tower. Win7 Home Edition, 32 Bit. Intel Pentium 4, dual 2.8 GHz. 2.5GB RAM, nVidia GF 9500GT 1GB. SATA 500GB + 80GB. Philips 17" LCD Monitor. Micronet ADSL Modem only. Saitek Cyborg Evo Force. FS 2004 + FSX. Briggs and Stratton Petrol Lawn Mower...Motor Bikes. Gas Cooker... and lots of musical instruments!.... ...!
Yamaha MO6,MM6,DX7,DX11,DX21,DX100,MK100,EMT10,PSR400,PSS780,Roland GW-8L v2,TR505,Casio MT-205,Korg CX3v2 dual manual,+ Leslie 760,M-Audio Prokeys88,KeyRig,Cubase,Keyfax4,Guitars,Orchestral,Baroque,Renaissance,Medieval Instruments.

Back to top

IP Logged

Reply #4 - Jun 8^th, 2010 at 9:56am

SaultFresh Offline
Colonel
Flight Instructor, CYKZ
Woodbridge, Ontario

Gender:
Posts: 134

The only problem with the 337 though is that all hell breaks loose if you lose the pusher engine. Also, I don't think the tail-boom design is much of an issue these days. Not when there are a few pushers kicking around that are tail-less.

Back to top

IP Logged

Reply #5 - Jun 8^th, 2010 at 10:41am

olderndirt Offline
Colonel
Flying is PFM
Rochester, WA

Gender:
Posts: 3574

SaultFresh wrote on Jun 8^th, 2010 at 9:56am:

The only problem with the 337 though is that all hell breaks loose if you lose the pusher engine.

Describe this. As I recall, a multi-engine rating acquired in a 337, restricted you to a 337 because engine out characteristics were so docile.

THIS IS NOT A PANAM CLIPPER

Back to top

IP Logged

Reply #6 - Jun 8^th, 2010 at 11:09am

SaultFresh Offline
Colonel
Flight Instructor, CYKZ
Woodbridge, Ontario

Gender:
Posts: 134

Well, from my understanding of the 337, which I guess is limited to the fact that I've never flown one, is that the engines are rather weak, even at 210 hp, and that sustaining flight, or climbing to a safe altitude, may be hard, or impossible, on a single engine. It is true though that it garners its own multi-rating, because it's center-line thrust. Aside from that though, the rear engine (again, from my understanding) is susceptible to over-heating and turning off without warning. In any case, I've generally just heard bad things about losing the pusher engine. Then again, I've never flown a 337, and I don't plan on finding out it's single-engine characteristics first hand.

Back to top

IP Logged

Reply #7 - Jun 8^th, 2010 at 9:37pm

olderndirt Offline
Colonel
Flying is PFM
Rochester, WA

Gender:
Posts: 3574

SaultFresh wrote on Jun 8^th, 2010 at 11:09am:

Well, from my understanding of the 337, which I guess is limited to the fact that I've never flown one, is that the engines are rather weak, even at 210 hp, and that sustaining flight, or climbing to a safe altitude, may be hard, or impossible, on a single engine. It is true though that it garners its own multi-rating, because it's center-line thrust. Aside from that though, the rear engine (again, from my understanding) is susceptible to over-heating and turning off without warning. In any case, I've generally just heard bad things about losing the pusher engine. Then again, I've never flown a 337, and I don't plan on finding out it's single-engine characteristics first hand.

Most modern light twins have relatively low single engine ceilings. An Air Taxi friend, in Alaska, decided to expand into IFR service so he looked for an affordable twin. Any twin used under Part 135 for IFR must be able to maintain the MEA on a single engine. Alaskan MEA's are higher based on a 2000' MOCA and his main route called for 10,000' on one. He ended up buying a BE50 twin Bonanza - nothing else in his price range could cut it. Wien Air Alaska, flying Fokker F27's had a special dispensation for this same route. After departure, they climbed to 16000' so that, in the event of an engine failure, they could 'drift down' - forward or back 'cause they couldn't hold the MEA (10,000') on one engine.

THIS IS NOT A PANAM CLIPPER

Back to top

IP Logged

Reply #8 - Jun 9^th, 2010 at 5:23am

Hagar Offline
Colonel
My Spitfire Girl
Costa Geriatrica

Posts: 33159

Going back to the original question. yancovitch wrote on Jun 7^th, 2010 at 6:46pm:

also....even in ww-1 there were pushers and tractors...why did the tractors win?...seems to me that pushers might be more efficient.....

I believe the pusher layout was used exclusively by British WWI designers. Not because it was more efficient than tractors. It was just one method tried in the early days of fighter aircraft allowing forward-firing machine guns an unobstructed field of fire. The Airco DH.2 was the first effective single-seater pusher fighter. It was made obsolete with the development of tractor aircraft like the Sopwith Camel & SE.5a fitted with reliable interrupter gear allowing guns to be fired through the prop without hitting it. http://en.wikipedia.org/wiki/Airco_DH.2

A certain Anthony Fokker invented the interrupter gear that gave the German Air Service the edge in 1915. http://en.wikipedia.org/wiki/Fokker_Eindecker

Founder & Sole Member - Grumpy's Over the Hill Club for Veteran Virtual Aviators
Member of the Fox Four Group

Need help? Try Grumpy's Lair

My photo gallery

Back to top

IP Logged

Reply #9 - Jun 9^th, 2010 at 7:57am

DaveSims Offline
Colonel
Clear Lake, Iowa

Gender:
Posts: 2453

olderndirt wrote on Jun 8^th, 2010 at 10:41am:

SaultFresh wrote on Jun 8^th, 2010 at 9:56am:

The only problem with the 337 though is that all hell breaks loose if you lose the pusher engine.

Describe this. As I recall, a multi-engine rating acquired in a 337, restricted you to a 337 because engine out characteristics were so docile.

The problem with the 337 is you might not notice you lost an engine until it is too late, putting you in serious trouble. If you lose the rear engine, you can't see it, probably won't hear it, and without looking at the guages, may not notice it, except for some really anemic climb performance. The reason your multi-engine ticket will be restricted to 337s if you get your license in one, is because you really haven't mastered how to fly single engine in a typical twin.

Dave

www.flymcw.com

Back to top

IP Logged

Reply #10 - Jun 9^th, 2010 at 9:38am

olderndirt Offline
Colonel
Flying is PFM
Rochester, WA

Gender:
Posts: 3574

DaveSims wrote on Jun 9^th, 2010 at 7:57am:

olderndirt wrote on Jun 8^th, 2010 at 10:41am:

SaultFresh wrote on Jun 8^th, 2010 at 9:56am:

The only problem with the 337 though is that all hell breaks loose if you lose the pusher engine.

Describe this. As I recall, a multi-engine rating acquired in a 337, restricted you to a 337 because engine out characteristics were so docile.

The problem with the 337 is you might not notice you lost an engine until it is too late, putting you in serious trouble. If you lose the rear engine, you can't see it, probably won't hear it, and without looking at the guages, may not notice it, except for some really anemic climb performance. The reason your multi-engine ticket will be restricted to 337s if you get your license in one, is because you really haven't mastered how to fly single engine in a typical twin.

Asymmetric thrust and VMC.

THIS IS NOT A PANAM CLIPPER

Back to top

IP Logged

	Search the archive: