Ghouly (oz15955)

About this Plan

Ghouly. Radio control sport model. Tail-less twin pusher layout. All-sheet construction. Uses a Jedelsky-style wing.

Quote: "Remember the Spooky (oz4496) published in AMI February 97? Well, here's its big brother, the Ghouly! It follows much the same sort of construction, but there are two motors to play with and two Cox 049's do sound a bit nice.

I opted for the servos in the fuselage version with the sliding plate mixer, but servos in the motor nacelles would work just as well, with electronic mixing. The maiden flight went well (to start with) and `Ghouly' climbed away like a super-charged arrow piloted by our very own DB. All was fine until one motor quit, Dave held it on the elevons momentarily, but with the balance point a little too far aft, Ghouly went into the fastest, flattest spin I've ever seen.

Back to the building board, stick the wing tips back on and devise some throttle control, move the CG forward and we'll try again. This time we definitely got the result we wanted with fast smooth loops and rolls, six flights and all the photos done in one go.

Now I know you are thinking, two Cox motors? Don't worry, your Uncle Ken will put you right, this is how it's done. Start No.1 motor (with a small starter, not the daft little spring thingy) and peak it up to full whack. Operate the throttle and it should stop after a few seconds. Now do the same with motor No.2. Refill both tanks, hit them both with the starter and leave them alone. Don't fiddle with the needles, just go out to the patch and chuck it. Trust me, if you insist on mucking about with the needles to get them synchronised, one of them will quit. You have my personal guarantee. Open the needles for the first start of the day, but after that it's the three F's: Fill 'em, Fire 'em and Fling it. Here are the details for setting it all up:

CG is at least 130mm forwards from the end of the fuz.
Just a smidgen of reflex on the elevons, 1 or 2mm is fine.
Elevator 10mm each way.
Ailerons 20mm each way.

I'll warn you now, I've got our DB tied to his drawing board doing the plan for the 'Ghostie' which is a three motor jobbie.

Designer's Notes: Ken has not made any construction notes and, in truth, none are needed, the drawings should make it obvious to any experienced modeller. However, I should comment on the need to select your wood carefully, you don't need to go to the tough stuff, and to suggest you build the fuselage first as this will allow you to locate the penultimate root wing ribs (R2) to fit snugly either side of the fuselage sides.

Before starting building do make your decisions on engines and radio control systems. We used Cox Black Widow engines and these provided adequate power and, with the CG corrected, safe performance on one engine. For safety sake I devised a cut-off system for the engines, operated from a single servo in the fuselage.

Operators of Cox engines will know that they are quite critical on the needle setting and this 'disadvantage' can be transformed into a safety feature. By installing a nylon arm (cut from a control arm) onto the needle valve and having an interference fit ie it is still possible to adjust the needle valve but having just enough friction to turn when the arm is operated, it is possible to cut the engine. Set the engine for normal maximum power and arrange the arm so that the servo will pull it back through 120°, this should be sufficient to cut the motor. Photos show the simplicity of the device.

Should you prefer it, you could fit 049 RC engines and arrange for beech engine bearers and fuel tanks in the nacelles, Flair distribute sonic neat 10 and 15cc metal tanks.

As Ken said, he used the 'push-pull' servo system for eleven operation, the alternative would be to fit separate mini servos in the engine nacelles to operate the elevens. Or, you could retain the 'push-pull' arrangement and have separate servos for the engine throttles - the choice is yours. It gets even more exciting with the three engine Ghostie!"

Ghouly from Aviation Modeller International, October 1998.

Supplementary file notes

Article pages, thanks to RFJ.

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