I enjoyed reading about some of you guys flying these busy little planes, what fun.
I have two kit models flying with blackwidows with stunt tanks [the old stock ones] and one made scratch from plans flying with a TeeDee .051 and the red fuel tank mount. Its a hand full!
My question is that while these three planes are a blast the fuel mixture is akward, sometimes you get a good run and sometimes not, aerobatics and combat changes this as well. Is there a better way such as pressurizing or bladder tanks? Can you pressurize the stunt tanks by capping off one of the vents. My experience with these was way back in the 70s and I never tried to modify the fuel systems. I also fly a Baby Flight Streak with a TeeDee .049 with a fusalage mounted perfect tank. Flies well until the centrifical force kicks in, then I am playing the mixture guessing game. I know most of this is the nature of the beast, but If you have any suggestions......Great and thanks

I've always run TD's on either bladder or crakcase pressure off the backplate. Are you up to modifying your perfect tank to be a uniflow? If so, that's the thing to do. If not, maybe someone else will have a useful sugestion.

Jim

Keester,
A couple of items that I have read on these forums. I HAVE NOT tried them so it is hearsay.
The red tank for the TD is supposedly plumbed for FF so you may get an erratic run.
Someone said the BW runs best if you have the cylinder sideways and the vents on top running inboard and outboard.
One I have tried: If you want to try another tank/mount for the TD you might try the Norvel tank. It is clear and you can plumb the pickup however you want it. The TD mounting holes fit.
A Norvel engine might not fit the Cox red tank, however, the Norvel crankcase is just a little bit wider.

George

Can you clairify Uniflo? And thanks for the responce.
Keith

For the Black Widow try replacing the needle valve spring with a short length of silicone fuel tubing and a thin washer. The washer goes over the NV threads so you may need to carefully file it out a little. The fuel tubing offers the tension to keep the NV from turning from vibration just as the spring does. But it also acts as an air seal to prevent any air passing in through the treads in an uneven manner.

Other causes of uneven runs are often related to the reed. If it's one of the old copper ones then get a rebuild kit that uses a mylar reed. These last almost forever. Also on older reedies sometimes the little O ring around the intake manifold that runs down the center of the tank leaks and that will upset the run.

For control line stunting with Black Widows or similar engines you need to open the tank up and ensure the pickup tube runs over to the point at the back of the tank that is up the side towards the outside of the circle. Looking at the engine from the rear the pickup tube end should be wedged into the backplate at the 3 oclock position. The fill and overflow vents should be just up and down regardless what you do with the rest of the engine configuration otherwise the fuel will flow out of them and drain about 1/2 the tank before you get into the air. With the pickup as said you will only get 1/2 a run if you aren't flying but once in the air the centrifugal force pushes the fuel to the outside and you'll pick up at least 80% of it with the pickup at that position.

TeeDee's run great on bladders but they are a pain to work with. You might try only using a 3/4 oz tank at most and keep the tank as close to the engine as you can. It's impossible to have it too close. Under no circumstances will you get a nice run if the tank is further away than about 3/4 of an inch.

If you do try the bladder you can get thin wall latex tubing at fishing supply outlets and that tubing makes great bladders. The tubing blows up to a diameter about the size of a hotdog and gets long really fast so be sure to allow enough length in the tube in the outboard wing.

That red mount is all wrong for flying control line. Perhaps for a trainer it would work but I'll bet the fuel pickup location in there is all wrong for stunting. If you knew where the pickup was located in the tank perhaps you could cant the whole mount and engine over at an angle so the pickup was to the outside of the flight circle but it's a big lump of plastic to have on what is supposed to be a lean and trim little model. Better to use in internal tank or bladder.

For the uniflow tank it's all about the vents. I tried to find a good explanation on the web but there doen't seem to be one that's easy to find so you are stuck with mine...

The pic below shows a top view looking down onto a tank in flight. The blue line is the fues being pushed out to the outside by the centrifugla force. The red tube is the fuel pickup and the black is the Uniflow vent. There is also a second vent you need in order to let air out when you fill the tank up but you must cap that vent off and use the angled one shown.

I started to write a description of why this system offers consistent fuel flow but realized that I don't know why. But it works. THe engine with a tank like this will run pretty consistently from beginning to end. The tank still needs to be positioned correctly in relation to the engine though. That means centered on the carb position horizontally and close to the engine. Maybe someone else can say why the Uniflow works.

The uniflow tank was invented by Edme Marriott of Dijon, France. in the 1600's. The tank is closed and air comes in through the uniflow tube that is submerged in the fuel, as shown in the diagram. The best I can do on a scientific explanation is to say that the engine thinks it is sucking fuel from the end of the uniflow tube. So it is the position of the end of the uniflow tube that is critical, not the position of the fuel pickup.

Incidentally Marriott was also the first person to test a model in a wind tunnel.

Jim

no solution about the fuel problem[&o],
but is the plan of the 'lil satan' of CG available somewhere??

regards,
marco leeflang
Netherlands

15% of the wing chord from the leading edge will work. Furthur forward may not hurt.

Jim

I could be wrong, but I think u07856 is asking if the plans for the Lil Satan by Carl Goldberg are available anywhere, not where to balance it.

I guess I'd like to know where I could get the plan for it also.

Phil in MN[8D]

Save yourself alot of wasred time and headaches and junk the cox engines. You can pick up a nice running .061 WASP AP HORNET for $40, and some spare glowplugs for about $4.50 each, as opposed to $9.00 for a COX glowhead. I also have a NORVEL BIG MIG .061[not the hipo version that is inconsistent] that is a nice running engine on 15% fuel. Top off fresh gallons of fuel right after you first open them with caster oil all the way to the top, and shake it up. NORVEL SELLS AN INTEGRAL FUEL TANK/ MOTOR MOUNT that will make retrofitting your LIL SATANS easy, and move the CG forward at the same time. COX can be made to run, if you want to make engine work part of your play time. I still run a RC glider with a BABYBEE and an external 2oz tank that gives me 15 minute engine runs, but once it wears out I will have washed my hands completely of the little %#@&*s

We used to run Cox Babe Bee or Golden Bee .049 engines on the 'Lil Satan. We'd open the tank and put the fuel pickup to the bottom center of the tank. We'd then mount the engine sideways so that the needle valve and cylinder pointed to the center of the circle. Om flight, centrifugal force kept the fuel from running out, and the pickup was on the extreme outside of the circle.

You could do the same thing with the Black Widow engines that had the integral tank. The Cox tank/mount for the TeeDee .049/.051 could be mounted the same way.

bax

For those of you interested I have very good copies of the lil' Satan full sized plans.
They are an exact copy made from the original Carl Goldberg plans of the lil' Satan.
They are $7.00 each and shipping is FREE. They will come folded in a 8" by 10" envelope.
The plans are full size.
Reach me at [email protected]

Thanks,

Paul Heimgaertner