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-   -   How to make an RV fly really bad!!!! (https://vansairforce.net/community/showthread.php?t=201471)

Dan 57 11-29-2021 10:31 AM

Quote:

This -6 had the most sensitive elevator control I have felt.
Generally speaking, yes, the -6 (and the -4, and probably the -3) have the most sensitive pitch. And roll. And maybe yaw (for the ones sporting the -8 tail). If it ain't over-sensitive, it permits precise flying, prompt manoeuvring, almost instant think/do reaction. And pure joy :D

One of the problems is that lot of builders build their panel (or add a sub-panel) much taller than specified on the plans, then load the panel with clocks or glass, and finally once all installed... have to cut the stick short to fit :o

Ralph Inkster 11-29-2021 10:31 AM

1 Attachment(s)
Good point Mike. You must have seen this issue (too) many times to prompt you to post it to this forum!


Quote:

Originally Posted by RV7A Flyer (Post 1571771)
From the Construction Manual, in the section on building the ailerons:
Quote:
The bent skins must be straight up to the radius and the radius must be between 3/32” to 1/8”. Match the degree of bend to the full size end view drawings. The upper and lower skin should just touch the spar when placed in position.

It should be noted to not make the TE bend any tighter than the radius measurements above. Minimum sheet metal bend radius allowances assure that stress cracking does not develop in the bend. I came across one elevator that had been over bent & cracked in some places, and had to re-skin the unit.

The manual describes a bending fixture to use during construction. I found this good for the initial bend of the TE, but later after riveting, to finish off with a hand seamer as Mike described. Specifically a vice grip style hand seamer that can be adjusted to gradually pinch in the TE radius to a consistent radius. The other trick I use with the vice grip hand seamer is to lay a towel folded 3 layers thick inside the jaw to protect the seamer from making pinch marks at the ends of the jaw all along the TE.

Ironflight 11-29-2021 10:47 AM

Many folks don't get the subtlety (or subtle difference) between teh final radius of the trailing edge bend itself, and the “flatness” of the slopes leading up to it - this is the thing that needs to be emphasized in the links that Scott provided. If you lay a straight edge on the surface of the control surface, it should be absolutely straight leading up to where the actual final radius begins - any bulge will make it more sensitive, and any con cavity will make the controls feel very heavy.

I haven;t flown as many different RV’s as Mike (probably no one has!), but I have flown a wide enough variation to have experienced heavy RV-3’s and extremely light RV-8’s - and everything in between. Our RV-3 is the most delightful handling airplane I have ever flown, and I have flown an RV-8 that was so much lighter in roll as to be uncomfortable. Examining the ailerons proved to me the importance of the shape of the surfaces ahead of the final radius.

BTW - our RV-6 (the tail number is N164MS….which gives you a clue to the builder….) is a perfect example of how the RV is supposed to handle.

And Mike - the RV-1, as revolutionary as it was for the day, felt heavier (and a bit slower in roll) than a typical RV-3, more like a -7. At least by the time I got my hands on it!

Paul

Mike S 11-29-2021 10:53 AM

Quote:

Originally Posted by Michael Seager (Post 1571681)
---I seldom write on this forum---

Michael Seager
rv6cfi@hotmail.com

Too bad, many of us would gain a lot from your wisdom/knowledge/experience.

azrv6 11-29-2021 11:19 AM

1 Attachment(s)
Fit this up against the aileron every inch along its length and you will quickly see, top and bottom, where the trailing edge needs adjustment. Made from the plans for my RV6.

Attachment 18872

rvbuilder2002 11-29-2021 11:54 AM

Quote:

Originally Posted by Mike S (Post 1571798)
Too bad, many of us would gain a lot from your wisdom/knowledge/experience.

I agree, but many would debate what he shares as well (from talking with him in the past, I think that is the reason).

jrs14855 11-29-2021 01:27 PM

Trailing edge
 
Several years ago Barnaby Wainfan did an article or maybe a series of articles on trailing edge shapes.
Based on Non RV experience it is possible to go overboard with the crimping and wind up with heavier than desired controls.
On my Wittman Tailwind I have all metal ailerons with just a slight bulge in the skin. The controls are perfect for me. Light stick forces but not excessively light and good centering.
On a Pitts the trailing edge is 1" wide and the ailerons are fabric covered. A bulge in the trailing edge results in zero centering force and when the stick is released the ailerons will move nearly to the stop by themselves. Proof that it's the very aft edge of the aileron that is causing the problem. With fabric covered surfaces the fabric normally bulges outward at cruise speeds or higher.
A square trailing edge 1/2" to 3/4" thick enhances the centering force of the controls and is alleged to be beneficial regarding flutter.
Extra used square trailing edges for a while and then went back to sharp edges.

PhatRV 11-29-2021 04:18 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1571785)
Short enough to clear the standard kit supplied instrument panel is appropriate.
Shortening to clear a custom, deeper, panel would be staring to deviate towards unacceptable.

Thanks for the info. I just measured my Infinity grip after I got home this afternoon. It is 14.5 inches to the top of the grip. It's 13 inches just underneath the button group (the top portion of the hand where the thumb and index finger grip the stick)


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