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

Michael Seager 11-28-2021 10:20 PM

How to make an RV fly really bad!!!!
 
I took my first RV flight in 1983 so I guess that means I have been flying RVs of all models for at least 38 years. I have helped a lot of people over the years either inspect and test fly or deliver and help check out a lot of people in their planes. I have test flew over 200 brand new RVs and flown more than 400 different airframes of all models of RVs. I have extensive time in all models except the RV-1. Last time I checked my logbook I had well north of 20000 hours in RVs.
I was ask to inspect and deliver an airplane this last weekend. I went and looked at it as I have done many times over the last 38 years. It was a very nice built and finished airplane, professional painted. On occasion I find an airplane that really stands out and this one was not in a good way.

This plane was so touchy to control that it was a handfull to fly even with all my experience. I seldom write on this forum but hopefully this will help some one else have a better flying plane. I have preached this to my students for many years. These two things will improve how your plane flys a lot. This will apply to RV-3 4 6 7 8.

1 Do not cut 6 inches off your control stick. It was designed to be the length that it was shipped in the kit. If you want to cut it down to put on a stick grip make sure you put back to the original length. Nothing I can think of worse than trying to negotiate a strong gusty cross wind with a touchy airplane that has the stick cut off to down between my legs. If you think I'm wrong on this take the steering wheel off your car and replace it with a 4 inch steering wheel and see how it goes. Van has wrote several articles on this and yet I still find lots of planes in the field that have really short cut off sticks. To make things even worse go to high altitude and load up the baggage compartment to make a rear CG and you have a really touchy hard to fly airplane when you cut the stick off. Over the years I used to carry some stick material with me so i could extend the stick back to the proper length before i ferried an airplane.

2 Make sure that the trailing edges of the ailerons are squeezed properly. This one very simple to fix item can make your ailerons nasty to fly. I find this a lot when test flying new planes. The trailing edge does not get squeezed enough and it makes this thing called aileron snatch. Aileron snatch makes the aileron very sensitive and unable to center. Give me 10 minutes and a hand seamer and I can fix this. A straight edge and a hand seamer can fix promptly. The particular plane that I delivered this weekend had terrible aileron snatch. Interesting that this plane had flown 700 hours this way and the original owners thought it flew great. I let the new owner fly it before I fixed it and he could believe how much different it flew.
I wonder how many other airplanes out their fly like this one did and could be improved a lot.

Michael Seager
rv6cfi@hotmail.com

mfleming 11-28-2021 10:26 PM

Thanks for the great report and tips Mike.

gotyoke 11-29-2021 12:08 AM

You have me extremely curious as to why these two things apply more to the 3 through 8 models and less to the 9 through 14 models.

BobTurner 11-29-2021 01:42 AM

Quote:

Originally Posted by gotyoke (Post 1571693)
You have me extremely curious as to why these two things apply more to the 3 through 8 models and less to the 9 through 14 models.

The models listed have Ďfoldedí trailing edges on the ailerons. The 10 and 14 have 2 piece, riveted trailing edges, which cannot be squeezed.

pgroell 11-29-2021 01:48 AM

My experience too
 
Regarding nį2 : I flew my RV-7 for 8 years with very light ailerons without this being a problem to me, I then participated in a formation training camp and a pilot I was flying with told me that the ailerons were indeed very light (which did no help maintaining position). Inspection on the ground showed some pillowing between the aileron ribs and a too great radius at the trailing edge.
I did some trailing edge squeezing, progressing slowly with some test flights between each iteration.
Once satisfied, I felt initially that the ailerons were a bit heavy but after a few flight the feeling is that roll control is much better and that the pitch an roll axis are better balanced.

Dan 57 11-29-2021 02:42 AM

Quote:

well north of 20000 hours in RVs
in 38 years = 526hr/year. Congrats on those impressive figures :cool:

And thanks for those 2 golden tips, let's hope present builders are listening ;)

Walt 11-29-2021 05:19 AM

If I may, add the elevator TE to that list, I've "fixed" a number of twitchy auto pilot problems the same way.

Sam_B 11-29-2021 05:19 AM

Quote:

Originally Posted by pgroell (Post 1571699)
Inspection on the ground showed some pillowing between the aileron ribs and a too great radius at the trailing edge.

Iím not flying yet, but this thread has grabbed my interest. I realize that this is probably a progressive adjustment, but is there a ballpark number for a radius that we should be aiming for?

goatflieg 11-29-2021 05:26 AM

Mike, thanks for the tips. I found it necessary to cut my RV-8 stick down to clear the bottom of the panel; I have the stick grip positioned so it just barely clears. Bruce Bohannon's RV-8 has a welded-up stick with an aft offset. When I trained with him, I made a habit of holding the stick low so my grip would approximate what I have on my aircraft. It will be interesting to see if it gives me trouble once I'm getting formation training.

NYTOM 11-29-2021 06:25 AM

Eye opening
 
Iím sure this post will have a bunch of us wondering where our planes fall in this trailing edge spectrum. In my quest to get the optimum qualities out of Vans design, does anyone out there have before and after photos of a corrected poor trailing edge. If anything, just to compare our edges to a property formed edge.
Thereís most likely a lot of RVís out there that could be greatly improved and much safer. :)


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