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Old 03-23-2007, 09:59 AM   #18 (permalink)
paffy
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Default Re: Spins -- Final Chapter

Kris, I think it's a shame that you create a nice video and then spoil it by information in direct opposition of what the rulebook says.

If you don't like the rules, propose a change. The rules are not clear on when does the deducting start. I'm aware of two camps. One starts deducting from the AoA just prior to break (like the post above suggests), the other starts deducting from where the attitude of the plane falls through horizontal.

So let's say most planes stall at around 12° AoA (not 45° !!). That should create a 1 - 1.5 point discrepancy between the two camps. Definitely better that way than one judge giving 0 and other 7.5 in my opinion. Every full scale spin video from professional pilots (with commentaries) I've seen shows:

a) power off
b) keep altitude by feeding in elevator (until it buffets real hard)
c) stall (nose falls straight down)
d) rudder in the direction of the spin (split second after the nose starts falling)
e) autorotation

That's why I prefer to give pilot until the plane gets horizontal to initiate the autorotation, but I would change that practice, if the rulebook became more specific.

Popups - not necessary on properly setup plane, but better than nothing. Most of the time, it will bring at least a deduction for change in flight path on entry. It's hard to do a pop-up without the plane climbing somewhat. If the plane doesn't have enough pitch authority to keep the wings beyond stall AoA to begin with (hence the need for the pop-up), it's quite possible that after the pop-up, it will simply fly out of the stall (like harrier to normal flight transition) and then spirals in instead of autorotating.

Bottom line (IMHO) is - work on your elevator travels and experiment with CG, before you try to master a questionable "pop-up into a spiral" maneuver.

The expression "ZERO airspeed" and "stall/spin" should never be used in the same sentence. You could say groundspeed, but that's not really relevant to anything. Again - refer to rulebook. This was plaguing pattern rules for years, where they wanted the plane "to stop".

Guess what - if planes would stall at ZERO airspeed, we wouldn't need runways. We could simply slow it down to ZERO and touch down...

P.
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