RV-7 Elevator Stiffeners

Dave Watson · #1 12-15-2008, 10:42 PM

I'm having problems understanding the plans description for creating E-720J,K,L (elevator stiffeners). Here is a picture of the plan instructions:

So I take the stiffener bundle containing D,E,F, (the longest is D), trim 1 7/8" from the aft end, and I end up with a stiffener that is over an inch too short. I called Ken at Builder's Assistance and he said do exactly as I did and the stiffeners should be the correct length.

Ordered and received a new bundle, checked again that if I trimmed 1 7/8" from new E-720D that it would indeed be too short for the E-720J stiffener position. I ended up measuring the required stiffener length and cutting a "D" to make a "J" but it's bothering me that I'm doing something wrong.

Anybody experience the same thing or can see what I'm missing?
Thanks,

MNForrest · #2 12-15-2008, 11:28 PM

Maybe it's X=1 - as in "one" stiffener - cut 7/8" and so-on.

Just a shot in the dark.

N814P · #3 12-15-2008, 11:51 PM

Granted I'm not there yet, but looking at the E-720 Trim Detail on DWG5, it looks like "X" represents the distance from the second to the last hole on the stiffener. Look on the left hand side of the drawing, very near the center, where it shows how to trim the stiffener, and you will see "X SEE NOTE 1"

mototopo · #4 12-16-2008, 02:25 AM

Hi Dave,
I'm at office and I don't have the plans with me to check, but if I remeber correctly, the measure indicated on the plans are the distance frome the second aft most hole to the aft edge of the stiffener (1"-7/8, 1"-27/32 and 2").

Just be sure you make them starting from the correct "original" stiffener as stated in the note (E-720J from E-720D and so on). It should be ok. I had no problem at all.

When at home I'll check my plans to be sure.

Dave Watson · #5 12-16-2008, 11:48 AM

Ralph and Claudio, you are both correct. Thank you! I can't believe how long I studied the plans and could not figure that out. I was locked into measuring from the end of the stiffener - not from the 2nd to last hole. Funny how one can get focused on looking at something and fail to see the obvious solution.
Thanks again!