What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV-7 tail on an RV-6

Jtomlinson

I'm New Here
What problems are involved in swapping out an old RV-6 HS and Elevators for an RV-7 HS and Elevators? They appear to match exactly except for the skin thickness
 
Be very careful about shifting the CG aft, you may not have much margin now depending on which prop you are flying.
 
Having built both models, IIRC the Horizontal is the same in the box but the Elevators have a longer counterweight arm by a little. The plans called for removing some material from the HS to accommodate the longer elevator CW Arm. The 7 Elevators were also 020 instead of 016 material.
Of course things could have changed some but doubtful and BTW it appears that there are some if not many 6's flying around with 7 tails.
Maybe they will chime in.
 
Looks like you are talking about just the Horizontal stab and Elevators. If used together you should have no issues. The skins are a little thicker, but the counterweight design moves the weight more forward, so the total weight may not be much different. It is the vertical and rudder that has a decent weight penalty.

I have a -7 tail on my -6A, so this is first-hand experience. The -8/older -7 vert and rudder are ok (but a bit heavier) if you decide to swap those as well. The newer -7 (which is the -9) rudder is heavier still, so not the best choice.
 
-7 tail

I installed a new 7 tail on my -6....both vert and hori--with the -8 rudder.
I also went to electric trim over manual.
I like it, I do have the 0-360 and C/S prop.
One note.....original tail needed a rudder trim tab...new one does not.
 
..........original tail needed a rudder trim tab...new one does not.

Did you change the incidence of the new vertical stab or did you set it up the same as the original -6 one? IIRC, the -6 was supposed to be rigged symmetrically side to side and the -7 has some amount of built-in offset to counteract P-factor.
 
Did you change the incidence of the new vertical stab or did you set it up the same as the original -6 one? IIRC, the -6 was supposed to be rigged symmetrically side to side and the -7 has some amount of built-in offset to counteract P-factor.

Sorry for delay....went to SNF.
I centered the VS as perfect as I knew how....so no offset.
I even built a custom empennage fairing so no feedback from fitting a factory one.
 
I installed a new 7 tail on my -6....both vert and hori--with the -8 rudder.
I also went to electric trim over manual.
I like it, I do have the 0-360 and C/S prop.
One note.....original tail needed a rudder trim tab...new one does not.

How far did the CG move?
 
In my opinion, the best empennage for the RV-6 is the original RV-6 empennage.

It looks better and is lighter. It has not been proven that other tails improve the performance of the -6 other than the possibility of very slightly better spin recovery.

The bigger rudder has more authority, but because the larger vertical stabilizer tends to windmill more, the additional authority is needed. IMO, this comes out as a wash.

The .016" skins of the original elevators and rudder have not shown to be a problem if the trailing edge radius if formed properly. When I sold my -6, it had been flying for over 25 years with no cracks whatsoever.
 
Last edited:
Back
Top