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Original Message
"Vacuum-Cleaner-Sucky Spins!"

Posted by TomParsons on 05-20-03 at 21:32z
The good news- I've been taking advantage of some decent weather here in NJ, and gotten one or two hops in for each of the last several days- woohoo! The "other" news... well, let's just say I need work in all areas of acro. In particular, I have had some trouble with spins (currently working on plain 'ol one-turn spins). In short, my spins are really bad, as in the "I usually come out in the same hemisphere as I wanted" level of badness. And let's not even talk about the downline... I know the basic method of performing competition spins, and I know it's just a matter of practicing to get things better and more consistent.

But I had a specific question that might help me eliminate one area of random experimenting. After I put in the rudder, should I slightly ease off the back pressure to let the spin accelerate a touch? Does a spin score any better or worse if I do? Am I better set up for a clean transition to the downline if I do this? And how much total altitude should I figure on losing, assuming I want to come out at a good looping speed?

Tom P.


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Messages in this discussion
"RE: Vacuum-Cleaner-Sucky Spins!"
Posted by DaveSwartz on 05-21-03 at 04:29z
Tom

It is best to not accelerate the spin. There are no bonus points for speed of rotation and it is easier to accurately stop the spin if it has not been accelerated. Keep the stick fully back until after your anti-spin rudder input has canceled the yaw sufficiently that you can safely stop on heading by bringing the stick forward to break the stall. Remember that a spin requires two components: 1) Yaw and 2) Critical angle of attack. Once you cancel the yaw, you can safely stop on heading with forward stick. If you bring the stick forward too early (while yaw still exists) you could perform a cross-over spin. Conversely, if you bring the stick forward too late (with "anti" spin rudder still in producing opposite yaw), you may perform a cross-over spin in the same direction you were going in the first place.

A one turn spin is a higher K figure than the "larger" spins because the nose of the aircraft will be quite positive after the spin stops and you will need to have additional skill to quickly get it down to the vertical. Typical altitude loss for a Pitts is 1000-1200 feet depending on how much energy you want for the next maneuver. Like most maneuvers, knowing where to look at each segment of the spin makes a big difference in the outcome. You should be looking straight over the nose for most of the push to vertical, looking at your aerobatic sight only during the last few degrees to accurately set your downline. With experience, you will learn what speed on the downline you should have before starting the pull-out. In an S2B with an MT prop, I plan on pulling about 30MPH before the speed I'd like to see after the spin. Different configurations will require different speeds.

Fly high (5000+) when you are working on spins. We lost 4 Pitts pilots last month in two separate S2B accidents. The accident reports both "suggest" spins were involved but early reports are not reliable. One of the Pitts was on a training flight with student and instructor.


Dave Swartz
Fort Lauderdale, Florida
http://www.FlightFantastic.US


"RE: Vacuum-Cleaner-Sucky Spins!"
Posted by TomParsons on 05-21-03 at 15:53z
Dave S.- Thanks for telling me it doesn't help to accelerate the spin. I wanted to practice the right way, but it's relief to know I don't have to practice that!

>Keep the stick fully back until after your anti-spin
>rudder input has canceled the yaw sufficiently that you
>can safely stop on heading by bringing the stick forward
>to break the stall.

I'm definitely going to try this. I have been waiting on the forward stick until the yaw was completely canceled, and I end up wallowing around instead of crisply stopping the rotation.

Dave P.- I am in with the local IAC folks (Chapter 52), but I'm just getting started with solo acro over the last week or so. I got one of the guys to do some ground critique last weekend, but we didn't get to the spins. We had plenty of work to do just trying to round out my loops!

Thanks for the pointers, Daves!

Tom P.


"RE: Vacuum-Cleaner-Sucky Spins!"
Posted by djpacro on 05-21-03 at 09:54z
Tom - have you connected with the local Chapter of the IAC to get some critiquing and coaching?

Its been a very long time since I flew an S-1 but try this:
about 1/3 of a rotation before the exit direction briskly apply full opposite rudder, continuing to hold full back stick. When you want to stop the spin pop the stick forward to round about neutral.
Disclaimer - use for competition spins, up to one and a half turns or so, only.

Regards,
Dave Pilkington


"RE: Vacuum-Cleaner-Sucky Spins!"
Posted by Patty_Wagstaff on 05-27-03 at 01:42z
After I put in the rudder, should I slightly ease off the back pressure to let the spin accelerate a touch? Does a spin score any
>better or worse if I do? Am I better set up for a clean
>transition to the downline if I do this? And how much
>total altitude should I figure on losing, assuming I want
>to come out at a good looping speed?
>
>Tom P.

Tom

Don't ease off back pressure to let the spin accellerate. It will speed up the spin and keep the recovery less clean than it would be if you kept the stick all the way back. The slower the entry the cleaner the spin and try to keep it that way. However, if you ease in a little opposite aileron it will tend to flatten out the spin and stabilize it, making it look cleaner and make the recovery cleaner.

Re: altitude lost...plan on 1000' per turn, although it may be less. You have to go up high and experiment with it a bit.

Patty


"RE: Vacuum-Cleaner-Sucky Spins!"
Posted by TomParsons on 05-27-03 at 19:55z
Patty-
Thanks for the tip! I will try a touch of opposite aileron. It makes sense to me to try to stabilize the spin, given the swinging in pitch I see now.

I sure hope I get a chance to practice applying all this good advice before my first flight at Maytown on Friday!

Tom P.