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Old 4th Apr 2018, 14:48
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gasperh90
 
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Bell 206 Jet Ranger Take-Off Power Range

The Flight Manual of the Bell 206 (Allison 250-C20R/4 Turbine engine) says:

TORQUE LIMITS
Takeoff Power Range 85% to 100%
(Do not exceed 5 minutes)

I do not want to open a discussion at what sections of flight this operating range is permitted. It says "Take-off", but in reality it can also be entered during hovering OGE, conducting power-ON autorotations or cargo operations..however this is not my question.

I understand that Torque over 85% at speeds more than 80 kts and Torque over 100% regardless the speed has to do with transmission limitations and mast bending.


My question is this.
Which system is an actual limitation here?

Considering it is a 5 minute limit, in my opinion the system which is affected, is N2 blades because of high power setting and thus high temperatures, which cause blade droop on N2 blades.


I would like to know what is your opinion on this and if someone has any document or maybe manual which explains this? Thanks
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