Ben and Eddy,
I bought my RV-6 with a small tail, and later built and swapped in an RV-8 V-stab and rudder. Some observations with about 300-400 hours flown with each tail, but first a few caveats:
My plane is a Super Six, sort of a Rocket/Six hybrid, and not built stock. I changed to the 8 tail to add the rudder counterbalance, on the counsel of some racing RV friends. I did not feel the 6 tail was lacking in any regard, but with the big motor and speed capabilities of the plane, flutter margin was the driving factor. A stock 6, built to plans, and flown in its envelope has plenty of margin, so the stock tail is very sufficient. Its has very nice lines too (IMHO, and FWIW!)
My observations following the switch to the 8 tail, which is 5" taller than the 6 tail:
- My plane slowed 2-3 knots at full speed (larger aerodynamic footprint)
- Interestingly enough, I feel that I need slightly
more right rudder in all regimes than I did with the six tail. With the 6 tail, I needed right rudder in a climb, it was almost feet on the floor in normal cruise, and slight left rudder at race speeds or in a decent. With the 8 tail, I need a little more right rudder in the climb, and still need a touch of right rudder in a decent, or at race speed. I did not/do not have a fixed tab on either rudder. Go figure that one, eh! Its subtle, and both tails fly great on the plane...no complaints. Could be the taller V-stab with a touch of offset creates the situation (I kept that slight offset the same between tails). Could be the larger aspect ratio rudder makes a difference. Could just be the difference in construction (trailing edge radius, trueness, etc). Just not sure. This summer I made flat fin and rudder caps, that cut off about 1.75" of the 5" I gained with the 8 tail, as a hopeful speed mod, and surprisingly, it feels more like it did with the 6 tail. Will I get the speed back...I aint tellin' yet!
Stein, it would be very interesting to hear what your observations are on this right rudder requirement aspect, with your experience with all the tails.
- My observations during landings and ground ops are, no noticeable difference between the two. Crosswind performance and taxi feel the same to me. I can imagine a 7/9 tail would be more sail area if taxiing in a wind. The 8 tail doesn't feel different to me though.
If I had it to do over again, I'd perhaps build a custom 4/6 tail, and add the counterbalance to that during the build. Dave Anders did that on his fast 4, Greg Nelson did it on his fast F1 Rocket, and I think Robby Attaway did it on his fast 6, since sold, and being enjoyed by another VAFer. Not needed for a stock 6 (stock tail is AOK), but a neat idea!!
For Eddie: As far as adding a 7/9 tail to a flying 6...later 6 kits came with an 8 v-stab and rudder. I don't think they ever shipped with a 7/9 tail, so check with the factory on recommendations. Sounds like Stein did it, so it may be an option, but good to check for any caveats or additional info needed.
Cheers,
Bob
