RCU Forums - View Single Post - It's almost a prop plane, at least it ought to be fast.
Old 03-24-2009, 04:36 PM
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MJD
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Default RE: It's almost a prop plane, at least it ought to be fast.


ORIGINAL: combatpigg

I've got an old Q-500 with a V-tail that would take about 4 hours to convert. I would remove the engine and build a nose cone to house all the gear forward of the firewall.
The owner of our LHS stuck one on a Ringmaster when he was a kid and flew it at a local school yard on 60 foot lines.
An 8 oz bladder tank will fly a Dynajet around reliably for mebbe 3 minutes on naptha, you'll have about 4-1/4 lb thrust. 2-1/3rd oz/minute IIRC? Might need a bit of a subfin to bump up the area with the extended nose and all that gobbledygook hanging out up top.

Some aluminum lithoplate on the inside of the fins and on the fuse top might be a good idea. And have the tailpipe exit as far clear of the airframe as possible, keeping CG in mind of course. It's nasty air near the exit plane, beats holy bejeebers out of tail surfaces that get too close.

One of the mags had a blurb about a couple of guys who figured they'd build a moon rocket by mounting a Dynajet underside a Playboy old timer. Check out the climb now, suckers! Problem is, a Playboy can easily generate 4-1/4 pounds of drag and do so at surprisingly low speeds and suck up all that power in a blink.. so they ended up with a nice flying Playboy that went about as fast as a glow version and made an earth-shattering racket and sucked over two ounces of fuel a minute in the process! Still fun though. Let one rip in something clean though, different story!

CP, got a Dynajet kicking around? Go for it! My small pj is Dynajet sized, but the head is extremely heavy so the total engine weight is about a pound. More of a show piece than a go piece. The big one weighs less than twice that and is rated at 18lb thrust.

MJD