Good points, Kevin - the RV-8 probably does have a longer fuselage and bigger rudder than the S-2. FWIW the rudder pedal travel feels about the same - maybe a bit shorter, come to think of it - but of course you don't really know for sure until you measure it.
The RV's do very nice hammerheads - I'm looking forward to doing some with Kenny's smoke system. Should be spectacular!
Because of his composite 3-blade (fixed) prop, there was virtually no gyroscopic precession to deal with in the pivot, as expected.
With a metal blade prop which has high PMI, you generally need full forward stick when you fully depress the left rudder pedal in the hhead pivot.
Also, as you slow down in the vertical, you need progressively more right aileron to oppose torque - you can see significant aileron deflection in the video I posted, just before the pivot in the hammerhead.
And as slipstream contracts in the vertical, you will probably need a little right rudder as well towards the top of the vertical, to avoid dragging wing before the pivot.
Anyways, for a hhead pivot, the stick is generally all the way over to the right, and neutral for a composite prop, and full forward for a metal prop.
You simply wouldn't believe the stick forces required in the hhead pivot of the R-985 Stearman, to put it all the way in the front right corner. If you don't do that, the gyroscopic precession of the prop pushes you negative, on your back, will full left rudder, which is a wonderful inverted spin entry.
Thing about an inverted spin is that although it may psychologically upset the pilot with the unusual visuals, it's actually far safer than an upright spin because the rudder is in clean air, unlike during an upright spin where the rudder is blanketed by the horiz stab and elevator.
The result of this is that an inverted flat spin is a complete pussycat - I will happily quickly recover from one of those at 1000 AGL - but an upright flat spin is a horse of a different colour, and must be treated with great respect, because of the two turns (and much altitude loss) it may require to recover. Many dead people have discovered this little detail on their own, including that South African pilot at the AWAC a few years back that should have known better.
But as usual, I tangentially digress into the sunset.
More practically, you RV acro guys should get the following message out:
1) stick (elevator) forces are wildly different for solo and dual acro. I didn't run across that in (my admittedly less than complete) survey of RV acro material before I flew the maneuvers off in Kenny's RV.
It's worthwhile noting that when you are solo, a substantial pull will be required on the stick to obtain the required +3/+3.5 G for any vertical maneuver (loop, 1/2 cu-8, hhead, etc), BUT if you have a pax in back, nowhere near as much pull is going to be required to obtain the same G, because of the drastic aft movement of the C of G. That's a trap that you need to educate new RV pilots on, to avoid excessive G in the first pull to vertical, with a pax in back.
2) considerable rudder pedal force is required for the hammerhead pivots, compared to other aerobatic aircraft I have flown (Citabria, Decathlon, Pitts, Stearman, Waco, Harvard, PT-22 Ryan, PT-19/26 Cornell, etc, etc).
I need to fly Kenny's RV-8 a bit more and get the airspeed down at the pivot, and see if that makes a difference. I did quite a few hheads in his RV-8 friday with different pivot speeds, and it didn't seem to make any difference. I have a sneaking suspicion you're onto something about leverage/gearing/pedal travel.
Also it would be fun to fly some surface acro in it with a helmet cam, and post the video here!
Too bad Freddy isn't here right now - I'd love to add the RV-8 to my ICAS SAC card! I'm a bit like Rob Erdos that way
Isn't there some guy at OSH that flies solo acro in an RV? I remember vaguely seeing something up in the sky like that - one of the Aeroshell T-6 guys?
