Removing washout

[Willja67 144]

My Model 1 wings were built with a 2" block under the spar to set the washout as opposed to the 1 3/4" block called for in the plans.  I never flew it but was told it cruised at about 65 mph. This is about 10 mph slower than most of the cruise speeds i have heard for the early foxes with 65 hp and I suspect the increased washout plays a big role in that. 

Just fyi the current model 7SS uses a half inch spacer.  I wonder how much faster the early foxes could be with that amount of washout? I've read a few posts on the subject but didn't  that see question answered.

In any case I'm interested in cutting off the aft upper end of my lift strut and installing a rod end in the hopes of removing as much twist as possible. I've read a few posts on the subject.  I saw the caution about fuel tanks. I have 1 6 gal aluminum tank in the right wing so I know I can't go crazy. Do you think it's possible to get a full half inch out of it? Or will I be lucky to get even that extra 1/4" out?

Any things that i need to be aware of if I go this route?

[TJay 1041]

The first issue I see is your poor glue joints from the wing rib to the spars will be so stressed they will eventually pop loose.  I would adjust your prop first and see if that helps.

Edited 1 Oct 2023 by TJay

[saskavid 47]

Most if not all of the avids were built on the same washout level using the 2 inch block. Depending on engine some mk4 planes can do 125 mph with that amount of washout.

Edited 30 Sep 2023 by saskavid

[nlappos 413]

Washout is one of those internet things where an idea with almost no merit becomes a full on debate point. Ethanol in fuel is another thing that somehow is deemed pure evil, but let's save that for another day.

The amount of washout on an Avid is low, but in the pack for all airplanes. Reduce the washout at your own risk, it serves a real purpose in providing roll control while near stall. Somehow washout gets to be the whipping boy for reducing cruise speed, I am not sure why. A degree or two reduction of angle of attack at the wing tip actually makes the overall wing more efficient, since it makes the lift distribution come closer to the ideal elliptical wing.