Questions on the history of the RV-6 Rudder

Guys that have been around long enough to remember may have the answer to a friend's question.

He is soon to be test flying his RV6A that started life before the counterbalanced rudder.

His question is why did Van's go to the counterbalanced rudder on the 6?

Since he has the non counterbalanced rudder and I have the original counterbalanced rudder I built when my kit was a 6, I offered to give him mine because I have the free replacement larger one that is now recommended for the 7 (not built yet).

Before he goes thru the trouble of removing and reinstalling fairings etc., he would like to know why Van's switched.

Thanks!

Two reasons were given- parts commonality (same rudder as the newly introduced RV-8) and better lateral stability with the larger rudder and VS.

Brantel said:

Guys that have been around long enough to remember may have the answer to a friend's question.

He is soon to be test flying his RV6A that started life before the counterbalanced rudder.

His question is why did Van's go to the counterbalanced rudder on the 6?

Since he has the non counterbalanced rudder and I have the original counterbalanced rudder I built when my kit was a 6, I offered to give him mine because I have the free replacement larger one that is now recommended for the 7 (not built yet).

Before he goes thru the trouble of removing and reinstalling fairings etc., he would like to know why Van's switched.

Thanks!

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Brian, the tail on my RV-6 is the older, small version.

It seems the reasons for the changes are as follows:

1) Main reason; parts commonality with the other kits which simplifies parts inventory for Vans.

2) The larger tail seems to provide more crosswind capability and also helps reduce the Dutch roll that is present in the small-tail planes in turbulence.

3) Has a thicker skin which reduces or eliminates cracks in the rudder skin.

There are no significant structural or performance issues with the different versions, so your friend shouldn't hesitate to fly whichever version he has. I think if your friend changes to the later version of the rudder he will also have to replace the vertical stab.

I believe the reason was that Van was going to let the cat-out-of-the-bag on the new RV-7/7A so the last of the RV-6/6A empennage orders got the 8/8A empennage kit Rosie

Sam Buchanan said:

I think if your friend changes to the later version of the rudder he will also have to replace the vertical stab.

<Brian, be sure you do get confirmation on this, I don't recall how the various versions of the emps fit together>

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Was not aware that the VS changed as well with this change to the CB rudder.

Can anyone confirm this?

If so, he won't be able to just bolt my CB rudder that I won't be using on to his VS? Hate it when that happens....

Rosie said:

I believe the reason was that Van was going to let the cat-out-of-the-bag on the new RV-7/7A so the last of the RV-6/6A empennage orders got the 8/8A empennage kit Rosie

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Haha, Yeah and my 6 kit was one of them. Thank goodness they offered an upgrade path for those of us that wanted to switch to the 7. Bought the conversion kit the same day I found out about the 7. Lucky for me, I did not have my elevators built yet so this was an easy conversion....

Spin Recovery!

The original, non counterbalanced rudder on the -6 makes for somewhat marginal spin recovery after more than 2 or 3 full turns. The -8 vertical was added to aid this. When this set up was tested on the -7, spin recovery was still marginal, so the -9 vertical was drafted for the -7.
I've done 6 turn spins both directions in my -6 with the non counterbalanced rudder. I don't recommend it!
As far as directional control, it is somewhat of a wash. The larger vertical tail makes the airplane want to weather vane more, but the larger rudder gives more authority to correct for it.
My opinion. $.02 please.

Original rudder is fine

Don't be afraid of the original rudder. Although I never spun mine 6 turns like Mel, I did fall into an inadvertent spin once during stall tests. Recovery was immediate and automatic in less than a turn by simply neutralizing the controls. And as for directional stability in turbulence, my 6A was far more stable than any 7 I've ridden in, and it didn't wag its tail like a 7x does. Personally, I think the original rudder looks better. I certainly wouldn't go to the trouble of switching it out.

RV6 and 7 rudder background

There is a SB on Van's site, SB 02-6-1, under RV-7/7A, titled Larger Rudder, that discusses the change in rudder size, why, etc.. Also note section in builder's manual that discusses intentional spins, etc. I have the smaller rudder in my current RV-6, ditto on my 1st RV-6. On the purchase flight back fm AZ to FL, I had at least a 15 knot direct crosswind at Sebring, yet was not out of rudder. I have about 450 landings in the RV-6. The real issue presented by the bigger rudder is that of further aft empty CG, unless you're going to be doing intentional spins with a far aft CG, and then letting the spin go more than 1-2 turns. Then, you might be in the wrong airplane for that.