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Is centerline thrust valuable?

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172driver

Well-known member
Joined
Apr 4, 2002
Posts
744
One of my CFI-I students is thinking about acquiring a Cessna Skymaster to build some multi time in between flight instructing. I guess he likes the Skymaster for the price and the safety. He has asked for my advice in the matter.

My question is this...do employers consider centerline thrust to be real 'multi time' ? I know it is legally a twin as it has two engines but is the time as valuable as in a plane with thrust on the wings?
 
No. Most employers and more importantly insurers make note of it in a seperate category. Not many students will want to get a ME rating in it either since they will be restricted to CT. The value in owning that plane will be for its transportation value only. They are easy to fly, stable, a little heavy on the controls, taxis like a drunken sailor and slow. Rear engines on some have cooling issues. I would think insurance may be less in them compared to a conventional twin - I don't know.
 
I'd say as far as having to monitor two engines and the operations of two set of engine controls it would be beneficial. However, without the "critical engine" and "minimum controllable airspeed" factors (I'm sure they exist but not like in a twin with engines on the wings) I don't see that it could be as beneficial.

I think the Skymaster is cool too, espeically if you can get your hands on the military version (O-2). For building multi-time, I would rather have an older Baron or C-310. An Apache or Aztec would probably be nice but I've haven't flown one of them (yet ;) ).
 
I would say the Skymaster would be of absolutely zero value as far as building time for the airlines. Without asymmetric thrust issues to address, it's just not seen as a "real" twin. (that was the whole idea behind the centerline thrust concept, i think.) That being said, I think there have been lots of cases where skymaster pilots lost an engine on takeoff and crashed because they couldn't climb out, not because of a Vmc roll. I'd tell my buddy to get a Seminole if he wants to build multi time. Wish I could afford one.
 
"Not many students will want to get a ME rating in it either since they will be restricted to CT."

I believe this is information is outdated. As I understand it, you cannot obtain a multiengine rating in a Skymaster anymore.
 
centerline thrust

If you get your ME rating in a C-337, I belive you still get a ME rating, but it has a limitation to centerline thrust, meaning that if you want to fly any other kind of twin, you've got to take the checkride again. As far as building multi time for an airline, flying a mixmaster seems pretty useless (but the complex, high power time doesn't hurt ... at any rate, guess it's better for your total time than flying a 172.)
 
C-337 time

Although the push me-pull you Cessna and particularly its military variants are among my all-time favorite aircraft, unfortunately the multi time earned in them means little to the people to whom you want it to mean something. It's all because it is centerline-thrust time. The airlines, etc. much prefer that the engines hang off the wings.

Even the majors don't give much credence to centerline-thrust time. There are tons of military pilots whose multi time are in T-37 - T-38 - F-14-type aircraft. Time in these multiengine turbines are discounted somewhat because they are centerline-thrust. I recall seeing some kind of discount factor for this time on the United app years ago.

You can take a multi ride in a Skymaster but you will have a centerline-thrust restriction placed on your ticket. You can have it removed if you take a ride in a conventional twin.

Fly the airplane because you enjoy flying. I wish I had flown a Skymaster. But build the time you need in a conventional twin.
 
Still not convinced...

The limitation to centerline thrust only has been removed as an option to my knowledge. I understand that this was once the case, but I am fairly certain this has changed. In perusing part 61, I see no mention of this limitation. Can anyone shed some light? Point me in the right direction, please.

p.s. I know this isn't exactly an official source, but according to the relatively new Jeppesen Multiengine manual:
pg. 1-9 "In 1962, Cessna introduced the Skymaster. The aircraft was different enough from conventional twins to warrant a special mutli-engine rating limited to centerline thrust. The rating is no longer available, and Cessna stopped producing Skymasters in 1980..."
 
Just don't get your multi-rating in the thing. After that, multi time is multi time. Preferably though, you'd get multi time in a conventional twin like a Apache or and Aztec, just in case it comes up in your interview as "inferior" experience. My 2 cents.
 
Re: Still not convinced...

Bluto said:
The rating is no longer available, and Cessna stopped producing Skymasters in 1980..."
I find that very hard to believe.

For one thing, there are a number of examiners available to give a practical in the airplane. I found a couple here in Colorado on this FAA page. So, if the rating is no longer available, howcum there are examiners available to give it?

Don't believe everything you read. Once more, if you like the Skymaster, fly it. I would have. Just don't expect it to count for much if you need multi time.
 
Howdy!

Dig into the introduction to the commercial PTS. The regulation the centerline thrust is based on was changed to a more generic one allowing other limitations. These might be "limited to aircraft without rudder pedals" or "limited to day VFR only" and such.

I just enjoyed about 4 hours in a P337 as prep for a few hours of C336 time. Supposedly there are only 90 of the 336s left. (336 = 337 with fixed gear).

Pure fun, like most airplanes.

Fly SAFE!
Jedi Nein
 
Safety???

Hello,

I, for one, don't see any safety advantage inherent in a centerline thust configuration. In looking through many accident reports I've come to the conclusion that the problem with an engine failure in a piston twin is not usually one of control, but one of performance and the Skymaster performes just as badly on one engine as all the other pistion twins do. Also the configuration leads to other types of accidents not seen in conventional twins, like trying to take off on one engine. I'd really like to talk to the Adam aircraft people and see what data they have that 's shows this configuration to be so much safer than a conventional twin.

BTW, the skymaster does have a critical engine. It's the rear engine. According the Cessnas POH the climb rate with the front engine shut down is nearly twice that of having the rear engine shutdown. The rear engine does a lot to reduce the base drag of the aft fuselage.

I've heard Skymasters are maintance nightmares, but what twin isn't?

I would personally give someone just as much 'credit' for Skymaster time as for any comparable twin. The whole point is to show experience managing complex aircraft and a Skymaster is just as complex as a Seneca, Duchess, etc.

Scott
 
Critical engine?

Sorry to be nit-picky, but if the front engine decreased performance so drastically, wouldn't that make it the critical engine?
 
No. The critical engine is the one that will cause you the most problems if it quits. In the 337's case it sounds like it flies better with only the rear engine working than if only the front engine is working, therefore the rear engine would be the critical engine.
 

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