RV and flat spins

[dynonsupport]

Originally Posted by mosquito

The 'bouncing ball' AOA/stall audio alert in the video seems very intuitive. Does anyone know what box is generating that?

-jon

That's the Dynon D10A making that AoA noise. Way more useful than a display (which it also has).

[Doug]

Sandifer - Thankyou for your insights, appreciated.
I have aerobatic training (in a Chipmonk) and a logbook entry to prove it but this was many years ago and I am not willing to commit aerobatics in my RV-6 until I am confident with spins in general and that the '6 can recover from upright and inverted spins within my capability.
Can you comment about inverted spins in RVs - anything of note from your experience?

[sandifer]

Originally Posted by Doug

Can you comment about inverted spins in RVs - anything of note from your experience?

My inverted spin experience is limited to the Pitts, but I've seen a few RV-4's do them, including WillyEyeBall (Bill) here. Seems to behave pretty normally, though Bill could provide more info. Most aerobatic airplanes have normal spin characteristics either upright or inverted - not much difference in the mechanics.

[ChiefPilot]

Originally Posted by sandifer

My inverted spin experience is limited to the Pitts, but I've seen a few RV-4's do them, including WillyEyeBall (Bill) here. Seems to behave pretty normally, though Bill could provide more info. Most aerobatic airplanes have normal spin characteristics either upright or inverted - not much difference in the mechanics.

The side-by-sides are slightly different than the tandems. As Van and others have noted, after the first 1.5-2 rotations, the rotation rate increases noticeably and might be unnerving if you're not looking for it. They don't recommend spins in the side by sides.

The second thing about the side-by-sides is that recovery takes longer than it would in a normal acro aircraft. Figure 1.5-2 rotations after apply corrective inputs. PARE works, but the elevator needs to be forced to neutral - it wants to float up if left to it's own devices.

[n468ac]

Originally Posted by sandifer

Then you did something wrong for the first 4,000' or so. It wasn't the airplane. But I'm glad you figured things out. .[/b]

I sure did do something wrong! I wasn't trying to spin the airplane or do aerobatics, I was completely caught off guard when it went into the spin. Good thing I was at 8000'

[sandifer]

Originally Posted by ChiefPilot

The side-by-sides are slightly different than the tandems. As Van and others have noted, after the first 1.5-2 rotations, the rotation rate increases noticeably and might be unnerving if you're not looking for it. They don't recommend spins in the side by sides.

The second thing about the side-by-sides is that recovery takes longer than it would in a normal acro aircraft. Figure 1.5-2 rotations after apply corrective inputs. PARE works, but the elevator needs to be forced to neutral - it wants to float up if left to it's own devices.

It sounds like you are referring to what is commonly known about the RV-6/6A with respect to upright spins. Are you really talking about inverted spins? I've never known Vans to comment on inverted spin characteristics. I've never spun a 6 with the standard small vertical fin, but what you describe is consistent with what I've heard, and what Vans states about the 6.

But I have done the Phase I aerobatic/spin testing on a 6A with the larger RV-7 vertical fin (RV-7A for all practical purposes), and this totally changes the spin characteristics compared to what you describe. Even after 3 turns in either direction (fully developed), it stopped in about 1/4 turn, which is traditional spin behavior in aerobatic aircraft - same as my old RV-3.

Originally Posted by n468ac

I sure did do something wrong! I wasn't trying to spin the airplane or do aerobatics, I was completely caught off guard when it went into the spin. Good thing I was at 8000'

As a teachable moment, can you precisely describe how you found yourself in what you believe to be a flat spin without attempting acro? RVs don't easily enter and sustain spins without full rudder and elevator deflection held and maintained.

[ChiefPilot]

Originally Posted by sandifer

It sounds like you are referring to what is commonly known about the RV-6/6A with respect to upright spins. Are you really talking about inverted spins? I've never known Vans to comment on inverted spin characteristics. I've never spun a 6 with the standard small vertical fin, but what you describe is consistent with what I've heard, and what Vans states about the 6.

But I have done the Phase I aerobatic/spin testing on a 6A with the larger RV-7 vertical fin (RV-7A for all practical purposes), and this totally changes the spin characteristics compared to what you describe. Even after 3 turns in either direction (fully developed), it stopped in about 1/4 turn, which is traditional spin behavior in aerobatic aircraft.

Mine has the in-between fin & rudder - same as on an RV-8 - and my recovery definitely was longer than 1/4 turn after only slightly more than two rotations. I've only done them (intentionally) on one flight; no inverted system meant lots of cleanup afterwards :-(

[sandifer]

Originally Posted by ChiefPilot

Mine has the in-between fin & rudder - same as on an RV-8 - and my recovery definitely was longer than 1/4 turn after only slightly more than two rotations. I've only done them (intentionally) on one flight; no inverted system meant lots of cleanup afterwards :-(

I'm confused...you did an intentional inverted spin with no inverted oil system? Without inverted oil, I'd prefer to just shut the engine off and restart after the spin is done...done over a runway of course. Of course, if you have a carb, it quit anyway.

[ChiefPilot]

Originally Posted by sandifer

I'm confused...you did an intentional inverted spin with no inverted oil system? Without inverted oil, I'd prefer to just shut the engine off and restart after the spin is done...done over a runway of course. Of course, if you have a carb, it quit anyway.

Pretty much. It was on the test card, and I knew from others that there'd still be 10-15 seconds of oil pressure at idle. It's FI, so no issue there but I dumped ~2 qts.

[sandifer]

Originally Posted by ChiefPilot

Pretty much. It was on the test card, and I knew from others that there'd still be 10-15 seconds of oil pressure at idle. It's FI, so no issue there but I dumped ~2 qts.

Interesting. Just wanted to clarify since few would be willing to do that.