I purchased Robbie Attaways aircraft. It is unusual in that it has the small rudder but is balanced with a horn. He intended to race the aircraft and did several races. Does a balanced rudder increase flutter margins in the tail? I do know he also used the thicker skins off the 7 on the tail feathers. I will try and attach a photo.
George
From what I understand, Dave Anders also built a new 4 tail for his plane (or rebuilt his) and added the counterbalance to it himself. That (building a new 6 tail and engineering a counterbalance for it) was discussed as an option during my path to this tail, but the simplicity of an existing...and proven...design won the day in that decision. My building/engineering skills are not that of Dave or Robby...yet! Long way to go though!
Flutter margin is why I was encouraged to do it, and why I did it. Don't get me wrong, IMHO, a stock 6 built to specs and flown to Van's numbers is safe and sound, and the Vne is well known.
Though a Super Six is a different animal and sports a builder-assigned higher Vne (similar to a Harmon Rocket, which was the genesis of several of the original builder's specs and build mods), I look at this (and other safety mods) as giving the engineer back some his "margin". That's why my racing buds surrounded me and encouraged me to do it.
If the RV-8 Vne is 232 mph, and the RV-6 Vne is 210 mph, then the logic was some of that increase is from the rudder counterbalance. How much, if any, I don't know. Does doing this 8 tail mod to a stock 6 raise that 6's Vne? I don't know that either, and I doubt one would be told that by the factory. But if it is viewed as a "can't hurt" safety mod that provides additional margin when flying within limits (a stock 6's limits or a Super Six's limits) then it seems like a good project (for my purposes anyway), though certainly not required.
Rocket's don't have counterbalanced rudders do they?
JJ, Standard Harmon's do not, standard F1's do. Mucho discussion among the F1 boys about this topic, and some of them are among those that encouraged and mentored me along this path.
If you look at how fast a Harmon flies with a non-counterbalanced rudder, you could make an argument that my project was unneccesary. I just look at it as adding a little margin. I wonder if I can pitch for lower insurance rates now!
Hope we can fly some more form soon brudda!
About 2-3 knots as far as I could tell. Regrettable I did not do a before/after test.
Yeah just never noticed any handling differences in the bumps.
Yep, before I had to put a bit more pressure on the rudder on takoff. After it took a bit less. As speeds were slower it seemed to be more effective...in a hammerhead it went over a bit quicker.
Thanks Bob... I do miss my RV badly...I bought a C150 for an absurdly low amount and that's getting me to breakfast on the weekends. A couple of more months and I will have the rocket flying, then on to rebuilding the -6. And the really good thing is I have spousal approval to keep all three airplanes.
One thing to add. I originally had a wedge on the rudder about 6" long to get the ball to center. On the new VS I offset it 3/16" to the left and it flew ball-in-the-center...so thats always a good thing.
Copy all Bob, thanks! First, how cool is your wife?!?! That's awesome! I'm lucky like that too, though I haven't tried for multiple planes! Good stuff!
Flew 2 test hops today. Lot's more testing and eval to go, but early overall impression is that in most ground and flight regimes, I could not feel a major difference. Taxi handling was pretty much the same. Takeoff and landing rolls felt very similar...perhaps a little more responsive, but only incrementally. AM flight was in smooth air, PM flight was a bit bumpy (to pretty bumpy in a few spots). I didn't notice a lessening of tail wag in the afternoon either, but I don't have a well-defined metric for that. We'll see.
One odd result (that may be explainable) is that I felt I had to use
more right rudder in all flight regimes...just the opposite of what I expected. Before, in normal climb and loafing cruise, I needed some right rudder (decreasing with increasing speed of course); while in high speed cruise and descent, and at race speeds, I neded just a touch of left rudder. Today I needed right rudder all the way to race speeds (which I approached slowly, and only after some very good lower speed stability checks). Hmmm...
Then my chase pilot told me my tailwheel and TW fairing were cocked off to one side about 10-15 degrees! During reassembly yesterday, I had shortened my Rocket Steering Link to make it line up correctly (or so I thought). After the flights, we raised the tail to unweight the TW, and re-adjusted the link to make it the fairing line up better. We'll check the results on the next test flight, and hopefully that is the smoking gun, because I was expecting less rudder required, as was your experience. We'll see!
Did a 4 way speed run too, and saw a 2-4 knot drop. However, the test area was hot and bumpy (27 degrees hotter and 2-3,000 feet higher DA as a result, than my fastest previous runs). Between that temp diff and the cockeyed TW, I'm hoping the gap narrows. Lot's more runs to go before a call is made.
One place I did feel I saw a difference was slips to landing. The larger tail did have a bigger effect when slipping, and felt a bit smoother in the slip as well.
... but I have been working!
Bob Axsom
Yes you have!
My 6A is also red BTW; my painter calls it ridiculous bright. I'll post pictures next week.
Rediculous Bright Red...I like it! Look forward to the pics! I'd also love to get a look at those smaller wheel pants you mentioned...if they are faster than PR pants, inquiring minds wanna know! (Right Bob!)
Cheers,
Bob
