KayDee III (oz13744)


KayDee III (oz13744) by Howard McEntee 1962 - plan thumbnail

About this Plan

KayDee III. Radio control aerobatic model.

Direct submission to Outerzone.

Update 7/4/2022: Added article, thanks to RFJ.

Quote: "At the outset - before the aerodynamicists start giving me a hard time - I'll admit that many features of this plane exist simply because I like their looks! Thus it may be more a result of good fortune that she ended up as a very successful Intermediate class contest winner. This is the third which has been flown with our improved Kickin' Duck control system (Sept 1961 issue). This plane is rather battered after a year of competition flying, so a new one will soon be started.

This plane series began with Dale Root's Little Freak 27 (oz2145); my modified copy was a good rudder flier with proportional control. Initial changes consisted mainly of increasing the span to 48 in and fattening the fuselage a bit. Most of my jobs come out pretty heavy and this one was no exception! But with a Torp .09 engine she was quite a success. So much so that when I wanted to try inductive kick elevators I increased span to 56 in; with Cameron .19 power this was a nice little flier which taught me a lot about flying with proportional elevators - some of it the hard way!

This double-revised plane was shown in the original Kickin' Duck article (1958 issue of Air Trails Model Annual). She had no motor control and ended life with a wing loading of 23 oz/sq ft, considered extremely high for a plane of that size, in those days. However, I found the configuration so satisfactory that my next craft followed the same general lines, except it was again enlarged, this time to 60" span with greater wing area. The latter was to bring the wing loading down - by the time I completed my usual 'rugged' style construction that load factor was even higher! WL was around 27 oz when it expired. She had a Fox .25 and would perform any maneuver except outside loops.

I got a charge out of snap rolls and spin reversals, so I kept the CG quite far back. This made her spin all right but with that high loading and minimal power she would stall out of maneuvers and pop into a spin if not flown exactly right. This happened a couple of times not quite far above the ground - like on my first Qualifying flight at the Dallas Nats! Result: funeral services.

All of which brings us to Kaydee '3'. Again enlarged in span and area, she too has a high loading (the cement makers love guys like me!). Presently it weighs 6 lb 14 oz, has wing area (not counting center section) of about 650 squares - you figure out the loading, I'm afraid to! Flown with a potent .35, the ring-type Supertigre, and an 11-6 Tornado nylon prop this one is a crisp performer. Even at the high loading, she'll breeze through all maneuvers, including outsides. With careful construction (less fiber glass, a lighter hand with the dope brush), a modeler who builds light should be able to produce a fine performer from our plans at 6 lb or so. As for me, mine will doubtless be just as heavy - but if she flies as well as Kaydee 3, who's to complain?

Designed to be a good sport flier, we hoped she would do OK in competition with the KD system, too. So there is a considerable angular difference between wing and stab - if held in a long, steep dive, the plane has a moderate tendency to flatten the dive angle. Wing and stab both are at a positive angle to the fuselage center line because I wanted the wing backwash to go under the stab to some extent; thus, good elevator control is obtained with reasonable deflections. Also, this gives a certain amount of built-in engine downthrust. With that stab angle you might think the plane would travel tail high - but this is not apparent in flight.

Airfoil section is the 2415. I didn't want an aerial 'bomb' and this fairly thick section probably slows it a bit. Actually, she does travel at quite a good clip (with all that weight it has to!) you suddenly realize this as KD3 swishes past on a dead stick landing. Stab is flat with construction popularized by a fellow member of the NJRCC - and while it requites a mite more work to make we've found the results rug. ged and warp-resistant, as well as fairly light. (I finally got to use the word!)

The fuselage is sheeted throughout. I like to get at every element in a model without having to cut into finished areas, so I put a hatch over the tank compartment; this opening allows easy access to the engine, and it holds the battery pack in place.

That odd engine angle is the result of my preferring scale-like appearance. I just don't like to see a big hunk of iron sticking up from the nose! Originally I had intended to mount the engine horizontally, but that would have raised the cylinder considerably to obtain a handy angle for the exhaust stack. More practically, I feel the tilt-mounting deal has several advantages: it is hard to flood the engine with too much fuel when priming the exhaust - the excess drains right out. Also, this mounting setup brings the needle valve more nearly in line with the tank center. The mill is mounted as high as possible, to get its thrust line close to the wing center line, and for maximum prop clearance as well. A 'breakaway' radial mount plate, cut from 1/4 in linen phenolic sheet, has prevented engine damage on several occasions. It's a lot simpler and much faster to cut a new plate than to replace a bent crankshaft or broken case!

Fuel tank is cut down from a Dmeco 8 ouncer with internal plumbing radically changed per the sketches. Hobby shop 1/4 in OD and 1/4 in ID brass tubing was used for all new parts. Sections with bends were heated red hot, then cooled and cleaned off. Tank is held by cord wrapping over four wire hooks fastened to the mounts. There's space under the tank that some builders might prefer for batteries. All my batteries (four Gould 1.25SC nickel-cads, one Eveready #420 B battery) are on a removable slide in a compartment just aft of the tank. The B battery, in an Acme holder, is rubber banded well to guarantee reliable contact. Also on the batt slide: socket for all power connections, tiny 3 prong Crescent socket for servo battery charger..."

Supplementary file notes



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KayDee III (oz13744) by Howard McEntee 1962 - model pic

  • (oz13744)
    KayDee III
    by Howard McEntee
    from American Modeler
    January 1962 
    64in span
    IC R/C
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 21/03/2022
    Filesize: 993KB
    Format: • PDFbitmap
    Credit*: dfritzke
    Downloads: 407

KayDee III (oz13744) by Howard McEntee 1962 - pic 003.jpg
KayDee III (oz13744) by Howard McEntee 1962 - pic 004.jpg
KayDee III (oz13744) by Howard McEntee 1962 - pic 005.jpg

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