Rebuild of E-flite "diamante 25e

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6 years 2 months ago - 6 years 2 months ago #15815 by JonTappin
Replied by JonTappin on topic Rebuild of E-flite "diamante 25e
Hi Colin

After you put in the required up elevator trim, if it was the thrust line that was the problem, it would have pitched up when you throttled back to land. Did it do this? If not it is more likely to be an incidence problem. Assuming it is a symetrical wing section, you should have between 0.5 and 1 degree positive on the wing.

Glad you managed to get it down safely!

Hope this helps.
Last edit: 6 years 2 months ago by JonTappin.

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6 years 2 months ago #15816 by 4Pedalsfly
Replied by 4Pedalsfly on topic Rebuild of E-flite "diamante 25e

JonTappin wrote: Hi Colin

After you put in the required up elevator trim, if it was the thrust line that was the problem, it would have pitched up when you throttled back to land. Did it do this? If not it is more likely to be an incidence problem. Assuming it is a symetrical wing section, you should have between 0.5 and 1 degree positive on the wing.

Glad you managed to get it down safely!

Hope this helps.


Jon - Many thanks for your comments, I have shed time tomorrow & will check the airframe over with the incidence meter.
We never got enough elevator up trim to achieve hands off level flight, rather than continue fighting it I decided to go
for a landing, which was a good three pointer.
Regards
Colin

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6 years 2 months ago #15825 by 4Pedalsfly
Replied by 4Pedalsfly on topic Rebuild of E-flite "diamante 25e
Jon - I set the model up with the fuselage datum line at zero degrees.
Wing incidence 0 degrees
Tail incidence 0 degrees.
Motor Downthrust 2 degrees.
C of G spec is 127 to 140 mm - actual - 134 mm.
I'm proposing to lower the wing at trailing edge to give 1/2 degree positive incidence.
Is this the best way to go ?

Thanks
Colin

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6 years 2 months ago #15826 by JonTappin
Replied by JonTappin on topic Rebuild of E-flite "diamante 25e
Hi Colin

Yes you need incidence on the wing, with 0-0 you will need up elevator trim to fly level. I would add a minimum of 0.5 positive on the wing. Is it an easy job to add it?

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6 years 2 months ago #15827 by JonTappin
Replied by JonTappin on topic Rebuild of E-flite "diamante 25e
2 deg of down thrust sounds a lot as well, but probably best to change one thing at a time

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6 years 2 months ago #15828 by 4Pedalsfly
Replied by 4Pedalsfly on topic Rebuild of E-flite "diamante 25e
Jon - Thanks for advice, it's easy to add positive incidence to the wing & I'll do that first.
I can then assess thrust lines during later flights.
Regards
Colin

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