RAF stab ...

StanFoster

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I am going to be installing my Parham stab on my RAF this week. I know it needs negative incidence. I am asking those who have first hand knowledge of what would be a good initial starting point for setting this negative angle?

Parallel to the keel which would give it the same degrees of negative incidence as the keel is tilted in flight?

A few degrees nose down with the keel which gives it a few more degrees of negative incidence?

Or a few degrees nose up with respect to the keel which gives is a few less degrees of negative incidence?

I have been studying pictures of RAF's with Parham stabs..and it appears most are parallel to the keel. I have seen a couple that had the stab tilted nosed down with the keel...and one that was tilted up with the keel. My consensus is to go with parallel to the keel..as this definately is negative incidence and should be a good starting point. I am going to be able to adjust it by stacking fender washers on either the leading or trailing edge. Thanks for any responses..Stan
 

Aussie_Paul

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Since 1982 Gyro 5000+ mostly instructing, and approx. 200 fixed wing in the late 1960s.
Re:RAF stab ...

Stan, I would definately go negative, ie tail higher than the leading edge. It took us a while to realise that with a large thrust line offset like the Raf you definately need negative AOI. When you finally get around to doing your Raf properly!!!!!! LOL, and have CLT then neutral stab angle of incidence (AOI) is ok.

Aussie Paul.

Ps. Stan I hope that the last couple of posts has made it uneccessary to reply to your pvt email.

All the best to you Raf improvers!!!!!!!!!!!!!!
 

StanFoster

Active Member
Joined
Nov 16, 2003
Messages
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Location
Paxton, Il
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Helicycle N360SF
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Re:RAF stab ...

Paul: Thanks again..as you posted in the other forum as well. I will start out with 3-6 degrees nose down in relation to the keel.

What adverse reactions occur with too much incidence besides more induced drag?

Good luck on the Hybrid. I am looking forward to seeing what you come up with.
 
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