ITT level observation

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metzgergva
Posts: 91
Joined: Wed Jun 28, 2017 8:09 pm
ITT level observation

Post by metzgergva » Tue Aug 14, 2018 6:06 pm

Another observation I would like to hear your point of view upon.
I’m a bit surprised that with summer temperatures slightly above ISA and at SL, the ITT already reaches red line way before 65 psi torque. ITT 790 C should becoming a limiting factor for max cont. torque only at high altitudes, according my information on the PT6A. Maybe possible to lower actual ITT calculation a bit so that the 65 psi can be used for take-off at ISA+5 or ISA+10.
Thank you for considering!
Alexander

Taguilo
Posts: 658
Joined: Sun May 11, 2014 11:49 am
Re: ITT level observation

Post by Taguilo » Tue Aug 14, 2018 6:35 pm

ITT values are correct.

Torque and ITT limits for take off apply for props at 2200 RPM.

Torque limit is top green zone (58.7) and ITT 790.

Torque limit is no longer sustentable above ISA+4 at SL (~19 ºC) without exceeding ITT; equivalencies following with altitude.

Max 64.5 torque is for props at 2000 RPM, and MAX Continuous, limited to 3 minutes.

Torque limit at ISA conditions can be maintained up to ~ 4000 ft. without exceeding ITT.

Tomas

metzgergva
Posts: 91
Joined: Wed Jun 28, 2017 8:09 pm
Re: ITT level observation

Post by metzgergva » Tue Aug 14, 2018 6:51 pm

Thanks for pointing me to check and in the POH I missed reading footnote 1) in the limitations table.
All good then!
Alexander


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