Hey folks....

Just thought Id ask a bit on this, because I know there are alternate ways of doing it.

What is the correct entry, and subsequent control movements for a good quality knife-edge spin ?

(lets assume your average 25-30% aerobatic airframe)

Bob

I like to enter from a slow knife edge. If I'm banked to the right, using left rudder, I'll wait for the plane to slow down, then use full down elevator and some left aileron to enter the spin. Some planes require more aileron than others, so finding how much your plane needs is important. Once the plane is established in the spin, I'll add some throttle to tighten the spin up. To exit the spin I will either release the controls and fly out of the dive, or give opposite rudder input to turn the KE spin into an inverted flat spin, then fly out of that.

I have had the best luck by setting up for a hammer head(stall turn). Half way through I add full down, opposite rudder and 1/4 throttle. timing is everything. I have one plane that will go in by adding full power and spoilerons to a flat spin. Only one will do it that way though.

David

ditto on entering from the hammerhead is my method of choice.
I first learned how the do the KE spin from this video. http://www.3dbatix.com/3dinstvideos.htm

I pretty much do exactly what is on the video and as daveopam said, it will vary a little from plane to plane.

My personal favorite combination is hammerhead into a KE spin into a blender.

Yep same as above. I find the most important thing is to get the amount of aileron right when entering. Some planes have a big sweet spot and some have a narrow one.

I used to use the hammerhead way but just last night I found a different way that works well for my Cap232. Go straight up, chop the throttle, push the nose over and hold full down elevator and just as it starts to point straight down add whatever rudder I wish in the direction I wish to spin and just a touch of opposite aileron and then add throttle. not all at the same time but all within a second or two. As with the other ways to enter it, timing is everything and it seemed to eliminate dropping into a flat spin that can sometimes happen using the hammerhead way. If I got the timing wrong I would end up in a tumble which also mnake for a great exit if you have the altitude.

I tried it the same way with a big Yak and could not do it but the hammerhead entry worked just fine

I have tried this several times with my 85" Yak. I can't get it! I get a couple of rotations (if I am lucky) in the knife edge spin and it drops right into an inverted flat spin.

Too much power? Not enough power? Too much elevator? Once it gets into the spin I'm staying off of the ailerons. *shrug* On sims I can do this manuever with 3 different entries and transitions into other manuevers but get a real plane up and I botch it every time.

Shakes,

You need gobs of elevator travel along with power. It's actually not easy to tell which is the problem you are having not knowing the amount of throws you have and the engine/prop combo.

I know someone that has a big Yak that will do it with 50 degrees of elevator and a DA50 turning a 23X8 Mezjlik on a tuned pipe

I know another one with the same size Yak with a MVVS58 and a 24X10 NX but a little lacking in the elevator throws and he will get part of one turn and instant flat spin

I think the best plane I have ever flown for a KE spin is an Ultimate. My GP Ultimate with 45 degrees of elevator and a Brison 3.2 spins right around the wingtip (actually it looks more like it's spinning around the CG) and does it really quick to boot and it can be coaxed into this position from any number of starting positions. I beleive it's the short coupling of the plane is what makes it so easy to do with not much elevator throw

my big and small Ultimates are the same. I really have to back the throttle down on the big one though.

I start with a left hand knife edge and then throw both sticks into the upper left corners. They will start to tumble and then spin. Then I ease the ailerons over to the right until it hits the right spot. Then I pull back the power. Very choice maneuver.

Bill,

I have the 85" QQ Yak, DA-50 spinning a Mej 23x8 prop. Elevator throws are about 55 degrees. Rudder is around the same throw as well. I am slightly behind the aft recommended CG point (still flies great).

I tried different entries. First few times was the stall turn entry - got it on its side, reversed rudder input, full down and it tries to enter then rolls on its back and does a gorgeous flat spin.

Tried with a downline tumble entry which seemed to be more successful (downline, sticks upper left then slide out of the aileron) - spun 2 or 3 times and rolls over into an inverted flat spin.

Well put....

I've been flying bipes a little while now and it seems that just about any Ultimate does gyroscopic maneuvers very well. Basically if the maneuver requires spinning around the CG, then a Ultimate does it very well (read that as very tight and fast)

I remember doing my first inverted flat spin on a YS110 powered CG Ultimate. It seemed like I could flat spin forever and if I got it just right with the power and ailerons I could even get it to stop dropping. I could even get the spin very slow, but then the plane would drop like a rock

My 30% Ultimate will slowly climb in an inverted flat spin. It's a bit tricky but it will do it and remain fairly flat. KE spins and waterfalls are a blast and will scare the pants off of you at first as you will think you are going to pull the wings off.

So what it seems to boil down to, at least to me is this:

Short tail moment planes need good power and decent throw for nice spin maneuvers
Long tail moment planes need lots of power and throw for nice spin maneuvers

I could be wrong and please correct me if I am....

Here is a good example of an Ultimate doing some spinning maneuvers. It is not me but about 2/3rd into the video, you will see this thing wind up into a flat spin after passing through a KE spin and it's obvious they are impressed and a bit scared as he pulls it out fairly quickly

http://www.hiddenhangarrc.com/video/27_Ultimate.wmv

Shakes,

It sounds like you have enough throw and possibly power depending on the weight of the plane. A Da50 will get a 15 to 16 pound plane going but once around 17lbs or higher that is a lot of mass to get moving. You could try getting more throw but I do not think it will help. It could also be a matter of timing on you part. You are getting into it but you may be hitting it before the tail starts coming around.

Try going in from a downline roll. Kick the sticks into the flat spin once you get rolling pretty good, (blender) position and immediately neutralize the airlerons.

In the video I posted above, I make a reference to a section about 2/3rds into the video, at that point he is rolling straight down, enters into the blender but neutralizes the airlerons just before it starts to flatten into the flatspin, at this point he has all kinds of momentum for the KE spin. Watch carefully and you will see this happen but it happens very quickly

Power is everything on this maneuver on a Yak. On my two Yak examples, both are right around 17 and 18 pounds respectively the 17lb one has a tuned pipe on it's DA50 so it's putting out more power than a canister or pitts muffler.

The second one is 18lbs but has a 58cc on a pitts so it's brute power getting the maneuver started

I once ran into this on my Cap, I could get two or 3 turns before it would fall out. That was a 14lb plane with a Fuji 43. Now I stuffed a DA50 into it at 14.5lbs and with my throttle curve I'm at 1/4 throttle doing KE and watefalls.

I don't think its a weight to power ratio problem. The plane will hover around 1/4-3 throttle on a nice 72 degree day. Around 90 degrees and its hovering at half throttle. I think maybe though I haven't been giving it enough throttle though expecting it to fall into the spin around half throttle. I'll keep trying it and coming up on the power until I can be sure thats not it.