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zeroairspeed

Astar Torque Limits

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trying to come up with the answer. without going to Eurocopter. so that more can learn. Maybe it is just me that dosn't know.

 

AS350B2 torque limit with airspeed above 40kts is 94%

torque limit with airspeed below 40kts is 100%

 

is it aerodynamics, frame that is the concern.

 

where could i find that info. flight manual states the restriction but not the reason behind it.

 

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Someone correct me if I am wrong.......but I believe it has to do with mast bending, and the lack of destructive testing done by the manufacturer. I believe the limits are imposed by the FAA.

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As was explained to me, above 40 kts the torque normally delivered to the t/r for antitorque purposes is now going to transmission and transmission torque limit is exceeded if above 94%.

 

 

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Retreating tip blade stall may be part of it as well. I was told that is the reason for the Bell 206B/L limits on forward airspeed past a certain torque. But please correct me if I am wrong.

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AMAZING!

We're all professional pilots and there several answers to a simple question

Human\ factor and more trainng required...I don't fly the 350 but I'm ashamed to say I am checked out on it and in all honesty can't answer the question for sure !! More training required??!!

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Hello every one

 

Most small helicopters that I fly, torque is measured at the engine and the transmision is the torque limiting factor. The T/R takes +- 10-20 % torque in the hover, ounce the T/R is offloaded with forward airspeed with the verticle fin becoming more efficient, this 10-20 % torque can now be transfered to the main gear box exceeding its torque limitations.

 

Hope this helps

 

Frank

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For whoever cares about 206Ls:

 

The torque gauge yellow arc (5 minute limit on the L-4 only) has 84 kt (or mph?- don't have flight manual here now) limit because of mast bending. If you use 85-100% (75-100% on L-4) torque at full speed ahead all the time your mast will turn into a piece of spaghetti eventually according to Bell. This is from Bell's training course in Ft Worth.

 

By the way, on the L-4 you only need to exit the yellow arc momentarily and you are good for 5 more minutes of full pulls.

 

I have flown with several pilots who don't know this.

 

Anyone headed for training at Bell Ft Worth in Jan, I will be there with bubbles jan 12 for flying and maintenance courses.

 

Can't help with Astars- never flown one and can't speak French.

 

B.M.

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i like the t/r to transmission issue being the case. but sure get a number of answers. I know we all fly within the numbers, just thought to wonder why.

I have sent an email to my trusty Eurocopter guy. hope to get an answer soon as i hear anything back. Maybe company Chief Pilot or Check Pilot would know.

 

This has been good. I thought it was just me that did not know.

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