Re: Tuft test video


Jay Scheevel
 

Hi Michael,

 

Yes, the trim changes with power, but only if you want to stay level 😊.  In any case, I do most of my trim changes in flight using the reflexor, but I do have spring-loaded trim on the elevator also.  I pretty much only use that elevator trim in the pattern to set up my landing speed. You can do this set up in the patter with the reflexor only, but you have to be comfortable with higher angle when flaring.  I did this for a year or so before I added the elevator trim.

 

I am not sure that it makes a lot of difference where you mount the reflexor on the span of the elevator, in terms of its impact on flight. I have it mounted where the plans call for it to be a couple inches out from the fuselage.  The only thing I can think of that might be a consideration is that, based on what  I am seeing from the tufts, the the entire airfoil of the strainer appears to be stalled constantly, so there is probably a lot of tug/drag on the strainer itself, which increases as the square of the airspeed. This force is applied to the mounts and also to the elevator itself. It is probably better to apply this large force closer to the inboard end of the elevator, since that area is the strongest part of the elevator and would only be 6 inches or so from the inboard bushing. 

 

There have a been a couple of guys who have lost the strainer in flight, so I beefed up the number of plies on the plywood mounting arms so as to avoid that happening to me. Now that I see the fact that it is stalled, maximizing the drag force at all phases of flight, I am happy that I did that reinforcement, and I would highly recommend doing that.

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Michael Dunning
Sent: Sunday, February 20, 2022 11:09 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Tuft test video

 

Jay, do you experience any trim changes with power? Hard to tell just how far inboard your sparrow strainers are from the video. I think Dave and Peter have pretty well convinced me to both add them and have them mounted about 2/3 span.
--
-MD
#2827 (still thinking about planning on visualizing how to finish building)

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