8KCABrett
Posts: 251
Joined: 1/5/2003
From: Davis,
CA, USA
Status: offline
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In the full scale Pitts type aircraft that is pretty much the way that you do a knife edge spin. Hammerhead left, then right rudder after about 90degrees of rotation and full forward stick. Aileron is held to the right (and it's already there in a hammerhead anyway). Aileron is variable through the spin and requires constant adjustment to keep it dialed in, and it takes practice to get them to really tighten up and stay KE, and because gyroscopic action of the prop isn't helping to keep the nose high, these are "accelerated" KE spins. The biplanes do not really like KE spins much when done right wing low though, and many Pitts pilots thought that you simply couldn't do them in the Pitts, but that is because they were trying them as the monoplane pilots do them. Which brings me to the comment that I wanted to add initially, which is my take on the best looking knife edge spin entry, as I do it in full scale monoplanes, and the method I use in my RC aircraft as well.
Pull to vertical as in a hammerhead, when you want to initiate thespin, reduce power to around 25% (in most of our 3D planes that's enough throttle for a goood pivot, if you are REALLY overpowered or underpowered it will vary of course-the objective is to have just enough airflow over the tail, but still are large power reserve available), kick full left rudder to pivot and perform a normal hammerhead, except that instead of stopping the pivot after 180 degrees of yaw, you keep the full left rudder in, and at around the 150 degree point of the pivot as the nose nears the vertical downline start adding throttle to around 50% (or however much you can carry without flying out of the figure). This blast of power will drive the pivot more strongly past the 180 degree point, and back up towards the "2nd horizon." As the yaw rate starts to decrease (around the 240 degree point) you are ready to come in with full forward stick and some left aileron. . .once in the spin, you should be hold full left rudder, full forward elevator, and whatever aileron it takes to keep it KE.
Depending on the aircraft, kicking just a moment earlier than you would for a hammerhead may help the pivot go beyond 180 degrees. Also, the amount of throttle you need to add back in towards the end of the pivot to drive the spin will depend on the model and powerplant, and once you get a nice KE spin going you can practice adding throttle to see how much you can add before it wants to spiral out of the spin, it may not do this, and in that case, going to just about full throttle will help to really bring the nose up towards the horizon, and to get a nice tight spin right around the CG. In full scale aircraft, and large scale RC models the gyroscopic action of the prop is important for driving the nose up, so right wing low, and forward stick is the ideal. (The same goes for flat spins, if upright, use left rudder, if inverted use right)
And now some really cool videos on the subject:
14 seconds into this video is an excellent helmet cam view and an external view of a KE spin in an Edge540, oh and at the very end is an awesome view of another KE spin!:
http://www.billsteinairshows.com/Video/20062007Video/BSA20062007DemoMedium.wmv
At 3:15 in the 2005-2006 Demo video (and the video archives page) there is a helmet cam view and an external view of a longer KE spin. There is lots of cool tumbles, snaps, torque rolls, tailslides and such in Bill's other videos so check them out at: http://www.billsteinairshows.com/BSADemoVideo.html
,Go here to see the KE spin in the Pitts S-2C from a cockpit mounted camera:
http://www.tutimaacademy.com/video_spin.html
quote:
ORIGINAL: Pat Roy
Another entry for the KE spin, but it works better for the larger planes with more tail areas.
Go vertical into a hammerhead. Carry just a touch of throttle so you won't make a full stop at the top. Just before the stall at the top go to max high rate rudder either direction. As the plane rotates to the horizontal on the rudder input, reverse the rudder to the top, add full up or down high rate elevator, depending on the desired direction of rotation. Hold the top rudder and max elevator, maintain neutral ailerons and throw power at it to get the rotation going. Use ailerons to counter roll coupling.
Bubba, just found this thread for the first time, what a great idea!!
< Message edited by 8KCABrett -- 11/18/2007 8:20:00 PM >
_____________________________
-Brett
Northern California Aerobatic Club:http://www.iac38.org/
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RE: HOW-To..3D maneuvers - 
