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Counter rotating multi engine

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Nope but like all other Garrets (J31, SA227,B100 ect) both props spin opposite to the "normal" clockwise spin.
 
The straight Navajo (PA31-310) doesn't have counter-rotating props but the Navajo Chieftain (PA31-350) does. The most noticeable difference is you don't need lots of right rudder on climbout in the Chieftain like you do in the Navajo. The other big difference is the obvious safety of not having a "critical" engine. Both are equally "critical" though. The drawback is that your maintenance may be more expensive because you have more different parts for the engines instead of the same exact engine with the same parts.
 
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Absolutely right. BOTH engines on a piston twin are critical. After an engine failure on a normally-aspirated light twin, what you've got is the same situtation you've got after an engine failure in a '182: You're in a glider. a Baron or Twinkie'll glide quite a ways on one, but you're not going too far.:)
 
SkyWestCRJPilot said:
The straight Navajo (PA31-310) doesn't have counter-rotating props but the Navajo Chieftain (PA31-350) does. The most noticeable difference is you don't need lots of right rudder on climbout in the Chieftain like you do in the Navajo. The other big difference is the obvious safety of not having a "critical" engine. Both are equally "critical" though. The drawback is that your maintenance may be more expensive because you have more different parts for the engines instead of the same exact engine with the same parts.

The only parts that are different are the prop/spinner, the crank, and the cam. The straight Navajo, there was a 300 (non-turbo) and the 310 (turbo) were conventional rotations. The Navajo CR was counter rotation with L/TIO-540-F2BD's at 325 hp and the short fuselage and the Chieftan with the 350 HP -J2BD engines and the long fuselage.

This doesn't take into effect the Colemill Panther converstion which is popular with the straight PA 31's.
 
WMUSIGPI said:
Nope but like all other Garrets (J31, SA227,B100 ect) both props spin opposite to the "normal" clockwise spin.
I think that that's only true with the Dash 10 powered MU-2s, but I could be mistaked there. I seem to remember something about an extra gear in the gearbox of that particular model 331 that caused the props to rotate "backwards".

Back to the original question. FAA definitions aside, I fully agree with SkyWestCRJPilot's statement that counter-rotating does NOT eliminate the critical engine, it merely makes both engines equally critical. All theories aside, piston powered, twin engine aircraft have two engines because they need two engines. Period. However, under certain, limited conditions, they can manage to remain airborne and controllable on one engine. Keep it above blue-line and the direction the propellors rotate is a mute point. The graveyards are packed with pilots (and their passengers) who either didn't understand or didn't believe that fact.
'Sled
 
Actually, both engines are interchangeable with each other. They are both IO-360-D's, but are bolted to the airframe 180 degrees from each other, so they are counter rotating, or contra rotating, depending on which one you start first, he he. The only difference are the propellers, one tractor, one pusher. The engine accessories are a bit different. The front engine has the only hydraulic pump for the gear and a gear driven alternator. The rear engine has no hydraulic pump and a belt driven alternator off of the prop. Neither engine has a vacuum pump, the gyro's are electric off of an AC inverter (26 v, single phase ac). The rear engine has a fire detection system installed from the factory, with four temperature detectors.
 
gern_blanston said:
Absolutely right. BOTH engines on a piston twin are critical. After an engine failure on a normally-aspirated light twin, what you've got is the same situtation you've got after an engine failure in a '182: You're in a glider. a Baron or Twinkie'll glide quite a ways on one, but you're not going too far.:)

And here I thought the Critical engine was the one that was still running!! :)


Some of the light twins do ok on one. The 58 Baron is pretty good on one if you are on the east coast with low altitudes. Got more time on one engine in those things than I care to remember from the old freight days! (shudder...)
 

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