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Flatter spins?

Old 10-26-2007, 09:32 PM
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Default Flatter spins?

Maybe you can help me with this one.

I have a rudder / elevator only sport plane that I can get some pretty rapid spins out of but I would like to try and flatten them out just a little. On high rates I'll enter a snap roll to the right and stall, and with the elevator full up and rudder right, it will spin but in a very nose down attitude. However if I use full down elevator the spin is pretty flat, with maybe 20-30 degrees nose down. Once in the spin, up elevator done nothing to bring the nose up. To exit the spin, opposite rudder is needed and it recovers in less than two rotations.

Left spins are the same except it will spin two rotations, pause slightly, two rotations, pause.... all the way down. Really weird looking.

CG is behind design specs, throws deflect pretty high (aprox. 45 degrees). Engine is a cox 049 so it runs WOT throughout the flight, and no ailerons of course.

It's really a hoot but I'm trying to squeeze just a little more out of it. Any suggestions how I can flatten the spins just a little more and can anyone explain the weirdness in the lefthand spins?
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Old 10-26-2007, 09:37 PM
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Default RE: Flatter spins?

with my flat spins..... you need the Aileron to flatten them out
Old 10-31-2007, 03:11 AM
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Default RE: Flatter spins?

Howdie diefluggeister, this is hkbii, You say that the cg is behind the specs ,I assume that means that it is towards the tail. try moveing the cg farther forward , towards the engin , this will make it lighter in the front and the elve will have more efect. go in small amounts or youll get tail heavy and thats no fun . looking at the pics it looks like a littel more down thurst and some right thurst, . that should help to make the plane more aro balanced. The undercamberd wing is makeing a lot of lift, the down thurst in the eng will help off set the climbing witch will let the cg move forward with out it getting tail heavy. the right thurst will help with the p factor that happens with an increse in the a.o.a. thats most likely why she pausees in the left turn. She shure is a pretty plane. I hope Im on the list. hkbii.
Old 10-31-2007, 08:54 AM
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Default RE: Flatter spins?


ORIGINAL: hkbii

Howdie diefluggeister, this is hkbii, You say that the cg is behind the specs ,I assume that means that it is towards the tail. try moveing the cg farther forward , towards the engin , this will make it lighter in the front and the elve will have more efect.

Moving the CG forward would make the nose heavier not lighter. To move the CG forward, you would have to add weight to the nose or take weight off the tail.
Old 10-31-2007, 09:30 AM
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Default RE: Flatter spins?

A throttle would help. I never tried a flat spin at other than low idle.

Boy, that set-up takes me back to the old free-flight and control-line days.
Old 10-31-2007, 07:29 PM
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Default RE: Flatter spins?

I took a vid yesterday. It's just right hand spins but you get the idea....

http://rcuvideos.com/item/5DHN663X785Z6PN0
Old 10-31-2007, 10:01 PM
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Default RE: Flatter spins?

I'd say your ability to spin at all with under cambered wing, only rudder and elevator, and full throttle is pretty amazing. Have you tried a spin from a decent altitude after you run out of fuel? I'm assuming you don't have a fixed fuel pick up since it probably won't stay inverted and starve the engine.

Dan
ORIGINAL: dieFluggeister

Maybe you can help me with this one.

I have a rudder / elevator only sport plane that I can get some pretty rapid spins out of but I would like to try and flatten them out just a little. On high rates I'll enter a snap roll to the right and stall, and with the elevator full up and rudder right, it will spin but in a very nose down attitude. However if I use full down elevator the spin is pretty flat, with maybe 20-30 degrees nose down. Once in the spin, up elevator done nothing to bring the nose up. To exit the spin, opposite rudder is needed and it recovers in less than two rotations.

Left spins are the same except it will spin two rotations, pause slightly, two rotations, pause.... all the way down. Really weird looking.

CG is behind design specs, throws deflect pretty high (aprox. 45 degrees). Engine is a cox 049 so it runs WOT throughout the flight, and no ailerons of course.

It's really a hoot but I'm trying to squeeze just a little more out of it. Any suggestions how I can flatten the spins just a little more and can anyone explain the weirdness in the lefthand spins?
Old 11-01-2007, 09:09 AM
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Default RE: Flatter spins?

Once the fuel runs out, setting up for a landing becomes a rapidly increasing priority! With enough altitude I could give it a shot. My gut tells me though that it would not spin well without power.

I have a clunk tank so it will run in all attitudes, but it is incredibly hard to fly this bird inverted with the dihedral, low CG, and R/E. I designed it to be stable in the roll axis for beginners. It's only through messing by around and increasing the rates that I found it would spin.
Old 11-01-2007, 01:59 PM
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Default RE: Flatter spins?

Wow, what an amazing cameraman!


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