Re: Sparrow strainer stall conundrum

Frankenbird Vern

 We think so..but remember that aerodynamics since 1980 has itself changed quite a bit, Brian.  Aerodynamics is still an evolving study. Actually Manufacturing and Structures Design is also. Internal Powerplant design is also improving.  AeroGeeks have learned a great deal since the days of Disco due to new tools like micro cameras that can be attached to birds.  

 No one knew back then how Peregrin Falcons could descend in an attack tuck at such incredible speeds. Impressive for a bird that is actually light weight compared to others like them. We understand more now. Still learning too.   

 So the answer is..probably.   


From: <> on behalf of Brian Larick <blarick@...>
Sent: Wednesday, February 23, 2022 10:17 AM
To: <>
Subject: Re: [Q-List] Sparrow strainer stall conundrum
My non engineer question.  Is there an efficient solution with a change to the shape of the elevator?  Would seem that if there was that it would have been developed a long time ago.


On Feb 23, 2022, at 10:48, Jay Scheevel <jay@...> wrote:

Thanks Michael,


I did read this after David pointed me in that direction. The problem with this approach is that the net moment arm is smaller because it is closer to the trailing edge, and the problem that the sparrow strainer is trying to solve is much larger than trying to balance trim spring loads. The basis of the problem is the shape of the elevator, which causes it to have a lot of upward deflection in the absence of the sparrow strainer. The issue that Burt was addressing was more of a tweak for builders that did not get everything perfectly set up while building.





From: <> On Behalf Of Michael Dunning
Sent: Wednesday, February 23, 2022 8:12 AM
Subject: Re: [Q-List] Sparrow strainer stall conundrum


Jay, that RAF CP 59 that Dave listed makes some interesting points. Burt recommended fixed tabs riveted on (and 10" long, to boot) to unload the elevator trim springs; different idea but something to think about.

Note that the attached pdf is one I found before he posted his repository link. Might be poor quality.

#2827 (still thinking about planning on visualizing how to finish building)

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