A Wido Satan -- the vintage Lil' Satan design with a Cox Black Widow. Ken reports below on flying the Wido Satan described in his earlier article. All photos provided by Ken Burdick.

As the Wido Turns

By Ken Burdick

Yes Folks, it's true.

As promised, I am reporting back to you on the flying characteristics of our vintage Little Satan modified for the Black Widow engine by Gene Pape. See the earlier article introducing this topic.

Is anything in life ever easy? No -- neither is running a reed valve Cox engine, no matter what Paul Gibeault says.

Yesterday was warm and sunny here in “The Loops” so what could be better than making up .012" x 35' lines and flying the Wido Satan? (How bout drinking a beer and reading my book.) Armed with the knowledge that I had finally tamed the Black Widow engine a few months ago, I tossed all into the truck and lit out for the field near the airport.

Here in the small town of Kamloops, people are just as irritated by noise as are in Seattle. Not far away is some sort of horse riding thing for errant kids or some such thing. While testing the Geezer Clown last year (muffler installed) I was informed that I was disturbing the horses -- they are directly under the landing pattern of the airport.

My launching stooge set up, lines on and adjusted and a new jug of Sig 35% nitro, it just doesn't get any better than that. The next 20 minutes were spent listening to the stupid engine burn prime. No matter what I did, the reed stayed wide open for some reason. Pissed? Yup. Back to the shop where I took the lil' darling apart and discovered that the Mylar reed purchased from Cox was pooched into a dome over the plastic fuel inlet. Now this is the engine that I spent so much time getting to run correctly. The particular setup is the plastic reed holder that slips over the tank stub that fits into the engine case. Taking it out, looking at it and putting it back into the holder did no good. Somehow it had grown in length! By carefully trimming off a little from each side of the rectangular shaped reed allowed it to now sit flat over the fuel inlet as it should.

Can we flying the stupid thing now?

Well, I am happy to report that Gene Pape's modifications worked perfectly.

The Wido Satan shot out of the launcher like many of its big brothers that we fly in big boy combat. The balance point of 1.20” C.G. was just what the doctor ordered. Stable in level flight, snappy transitions without “overturning” or not stopping a maneuver when you tell it to. Smooth square loops, inside and outside loops with no stalling and fairly tight diameter. Overhead figure 8's were no problem for the mighty mite and once the fuel system is improved, 40-foot lines will be easy for this combat wing.

Mine is slightly warped due to covering it with silk and dope, but it did not exhibit bad habits. The one-penny wingtip weight seemed to be just right.

The only problem I had was a short engine run.(50 seconds!) I believe this is due to the pickup tube being in a poor place inside the tank. Had I set the engine upright I think the pickup tube would be fine -- but no. I insisted in turning the cylinder sideways to the outboard side of the wing causing all sorts of issues with the tank pickup.

Ken's launching stooge, the Wido Satan and the flight box.

So -- here is a try at resolving my particular problem. Likely if you just leave things alone, you may avoid all this.

I bent a 1/16” piece of brass tubing into a 90+ degree. I ground a flat on the inside of the backplate and spot-glued the brass tube with CA. I followed this with five-minute epoxy as shown in the picture at left.

The placement of the tube is where the fuel pickup needs to be. I connected the pickup nipple to a small piece of surgical tubing, and the other end to my brass tube. Now I know exactly where my fuel line in the tank is positioned. Things like this rarely work out for me so I'll go flying tomorrow and report back to you, and yes, I will test run it here before driving to the flying field.

OK -- so now it's the next day and guess what? It won't run! As I suspected, the surgical tube is kinking inside the tank. It was replaced by the magical stock tube Cox uses for the pickup -- spring and all (picture at right). The stupid thing runs now. So we are now headed to the airport once again to irritate a stable of horses that might be better located outside the city limits.

No horses were harmed in the making of this ruckus.

I arrived, set up and launched. It ran, flew well but only for 13 laps maximum (sigh).

I am thinking to reduce the air intake back to stock and see if our draw improves any. While at the field, I tried capping the top fuel vent with no change. I tried capping the bottom vent with no change so I don't think it is a matter of misplaced atmospheric bubble in the tank but rather fuel draw causing it to lean out and die early.

(Sometime the next day) This is stressing me out, man -- it's a stupid .049 and it draws blood! (Cut finger.) I think our most infamous cuts are caused by Cox reed valve engines! I decided that the problems are most likely due to my modifications to the air intake. Knowing this might be an issue, I wisely bought a complete stock tank, backplate and reed from Cox. Only the tank had no vents! The backplate has one overflow vent sooooo -- I made the stock tank into a uniflow tank. (Oh, yes I did.)

Two tries at the uniflow tank.

It was easy to drill a smaller than 1/16" hole into the plastic tank and press in a brass tube, then JB weld it in place. The stock tank is using a stock spring-loaded fuel pick up clocked to the correct position. So folks, today we go bother the horses once again.

Stop the horse, I wanna get off!

OK, I'm back from the flying field. To say that the new plastic tank didn't work, is like saying the Titanic had a little trouble. The tank leaked from every conceivable factory made seal point. The backplate, the bolt holes, even at the engine where the gasket is! I first noticed this as cold raw fuel came dribbling down my arm after filling the tank -- "Oh, it's just the overflow not being capped” I thought to myself, I was wrong.

I actually got it to run and watched it blow bubbles from -- everywhere.

Note to self *Do not use plastic fuel tank.*

Back at the shop, I laid out all of my options. The best one seemed to be the metal fuel tank that sealed previously, and the plastic backplate that did not have an overflow nipple. The tank was not set up for uniflow, but that's pretty easy. Pull out the two small vent tubes, bend a 1/16" piece of tubing to a 90 degrees, enlarge the hole in the tank and epoxy in the uniflow vent. There are two tubes in the factory tank, one going up, the other going down so fueling is simplified. I am using the top hole for the vent so the bottom tube was pulled out, shortened to a stub and re-installed with more JB weld. The fueling will be through the vent and invert the whole mess until the fuel comes out the stub -- then cap the darn thing. Tomorrow we try once again.

As it often happens so far, it's tomorrow. The JB weld is hard on the uniflow tubes and a test run shows that the entire tank runs at the setting it began on -- just like a uniflow tank will allow. I even made a fitting for the vent tube that necks down from 1/16” to .010". This keeps the air blast from siphoning fuel out of the tank. We learned this early on in Vintage Diesel Combat while the poor guy holding the stinky thing was getting hosed with lovely smelling diesel fuel.

I am happy to report the silly project now runs close to 1:30+ minutes in the air on a rich setting. The really nice thing is that it maintained the same setting until it stopped, and it stopped rich. Testing was abruptly halted, not by disgruntled horsey people, but by a too low take off that removed the firewall. I'm calling this a success and get on to other things. I did make an auxiliary fuel tank if it comes to that. The tank is also a uniflow and can be mounted in the wing with a fuel line routed through a hole in the engines' tank and then connected to the fuel nipple.

What on ordeal! I'm so happy to give you the summary of this project inspired by Beaver Gene Pape. Here is a formula for taming your leaky old Cox Black Widow, for use on Gene's great flying Wido Satan.

  1. Use plastic backplate (metal ones are too heavy for the combat wing).
  2. Use metal fuel tank with mylar reed. Either old G clip retainer or separate retainer system.
  3. Make the tank into a uniflow by removing existing fill vents and use the holes provided. My uniflow vent goes straight down to mid-tank putting it about .4” from the pickup. The fill vent is flush with the bottom of the tank and capped off when running.

So dear readers, this concludes our story of “As the Widow Turns”

-- Kenny-b

This page was upated July 8, 2014

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