Zoot's Mixture

August 2020

The Artesian Sport Racer

Ready to fly, Zoot's new Artesian for Northwest Sport Race, powered by an O.S. FP .25. All photos by Mike Hazel.

By Zoot Zoomer

One of the best planes for our Northwest Sport Race event is, in my humble opinion, the Artesian.

Why? Well for one thing, it was designed specifically for the event. As you know, part of the rules for the event specify a kit design that falls within certain parameters. Sometime back in the 1980s, one Mr. Dick Peterson decided that he did not like the choices so he came up with his own design. Now normally this would not be allowed, but he took the extra step and had a kit-cutting company in California do a production run. I believe that 100 was the number he had made up. He then distributed the kits from his own home business and also several were placed in Northwest hobby shops. If memory serves correct, there were a few additional kits made after the initial production.

Anyway, so much for the history. The plane flies great, behaving like a real racer.

I have never had good luck with the Fox 35 engine for sport racing, but that’s just me. When we changed the rules not too many years ago to allow the O.S. LA .25 engines I decided to get back into the game. I had an old original Artesian kit in the stash, so put it together. Unlike the Fox, the LA engine has been friendly to me, producing several victories.

Now to the present: The rules for Northwest Sport Race now allow for fuel shutoffs and some other engine choices. I had been competing successfully with my racer without a shutoff against some shutoff-equipped planes. But with Racing sometimes there is some luck involved. Having your plane equipped with a shutoff is a definite advantage both for pitting and also the all-important safety angle. So it seemed like a good idea to incorporate a shutoff. The tank on my existing Artesian did not leave any room for a fuel shutoff behind the engine. And the tank works so perfectly I did not want to change anything, so that plane has been put aside as a back-up. I can also use it for the Super Slow Rat event when I go racing outside the NW region.

So, time for a new Artesian properly equipped with a fuel shutoff. With no more kits handy, I cut out the parts from scratch utilizing the kit plans.

With the new Artesian I decided to campaign an O.S. FP 25 engine. A new tank was built that would allow for placement of the fuel shutoff between the tank and back of the engine. I would also correct a flaw from some of my other profile fuselage racing planes: rubber band mounting. Nothing like a good pit fire for having your fuel tank fall off during the race. A very clean mounting can be done by simply having a long bolt run thru the tank for fastening. You have to plan carefully for this, however. There is a brass tube built into the tank running across the width, with a stub sticking out which keys into the outboard side of the fuselage. There is a blind nut on the inboard side of the fuselage for the bolt to attach to. Some foam padding is glued onto the back side of the tank for vibration dampening and also to help keep the tank tight in place when bolted down. This was the tank mount method used on John Thompson’s and my “Killer” NW Super Sport plane some decades ago. It literally raced over a couple thousand of miles and the tank mounting was never a problem. Don’t know why I didn’t remember this mounting method sooner.

Fuel tank is mounted by one bolt, which goes through the tank to a blind nut in the fuselage.

Front end view of the Artesian shows the coffin-style tank, shutoff and O.S. FP .25, with the ZZ Prop 8x6.

The tank is of the “coffin” shape variety, and with a uniflow vent fill tube. For the overflow vent I opted to use a one-way check valve instead of the pinch-off method. This eliminates one finger function for the pitman and is of course a fully automatic operation. So far I have had good luck with the Foremost Products glow fuel check valve. The tank capacity is 40 cc.

Close-up of the shutoff with the "stand-off" spacer to allow a straight-line fuel feed.

A second bellcrank inside the plane operates the shutoff, and keeps external hardware to a minimum.

Now for the shutoff: I had one in the stash so that saved some time from having to build one. The only problem with the design is that it would make for an extreme bend in the fuel line between the tank outlet and needle valve assembly nipple. Problem easily corrected by mounting the unit on a standoff, which allows a nice straight fuel line from tank to engine. In an effort to keep everything “clean” there is a minimal amount of shutoff linkage external. In fact all you can see is a small diameter cable emerging from the wing near the leading edge which hooks onto the shutoff trip wire. Internally, there is a reverse bellcrank installed toward the rear of the center rib. This converts the movement of the main bellcrank which “goes the wrong way” for a pull cable. The cable between the control bellcrank and the reverse action shutoff bellcrank is equipped with a slip knot.

Other notes: The pushrod emerges from the wing trailing edge thru a brass tube. That and the use of .078 wire for the pushrod eliminate any need for a fairlead. The engine is mounted on aluminum pads. The wheel is an antique HeliArc two inch. Prop is my own fiberglass copy of an APC sport 8x6. My first Artesian has always seemed a little light on takeoff, so the leadouts on the new one were moved back about 1/8 inch. The fuselage and tail are finished with clear epoxy paint and the wings have iron-on covering. Ready to race weight is 26-1/2 ounces.

See you at the Racing circle.

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This page was upated Aug. 11, 2020