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Building Tips and technical articles. => 1/2 A building. => Topic started by: John Skukalek on June 19, 2019, 06:09:20 PM
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Are these motors designed to run when they are inverted? I have one that starts and runs great. It is mounted upright. When I flip the airplane to inverted while flying it stops running.
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The Baby Bees I had as a kid came from the factory with the fuel pick up hose running down to the right (when looking from behind) and just above the bottom right tank screw. The factory fuel hose is not greatly flexible so it stays put and doesn't flop around. So, when you invert the motor the fuel hose is quickly (or instantly according to how much fuel is in the tank) sucking air.
Also the original Baby Bees had both the fill nipple and vent nipple on top of the tank backplate and extending only through the thickness of the backplate, so when inverted the fuel tank has no vent hole. The Golden Bee had a brass or copper fill line that goes from the top of the tank and down almost to the bottom and a vent line that runs from the bottom of the tank and almost to the top of the tank.
I've read in previous threads that if you want a Baby Bee to run inverted, 1) take the tank apart and run the hose higher up to the center of the outboard side of the tank, 2) after filling the tank, run a piece of fuel hose from one nipple and around the bottom of the tank and back up to the other nipple. Then cut a slit in the fuel hose under the tank. That way the tank is vented whether upright or inverted.
Joe Ed Pederson
Cuba, MO
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Thanks Joe, that's very helpful. Will a black widow run inverted?
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Black Widow will run inverted, the tank and tank back-plate are designed for it.
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There are two more ways to beat the system with a Babe Bee.
One way is to mount the engine with the NV and vents inboard and hold it so the fuel doesn't spill until the launch. Then you can have the launcher top off the fuel just before launch. You will get air into the vents without spilling any fuel. Of course the pickup needs to be moved the new outboard position.
The other way, which requires the drilling of one hole the tank and hooking up an external stunt tank. US kids figgered that out in 1959. All the Babe Bees at the Cerveny school had TeeDee cylinders and heads and outside tanks by 1960.
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Are these motors designed to run when they are inverted? I have one that starts and runs great. It is mounted upright. When I flip the airplane to inverted while flying it stops running.
On the plus side, if you got far enough to realize this, you are in the Top 20% of Babe Bee owners.
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Another option is to find a piece of fuel tubing that fits the filler nipples tight. Run the piece of tubing from one nipple all the way around the tank to the opposing nipple. Directly on the bottom opposing the fillers, cut a V notch in the tubing, this will allow for inverted flight
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Thanks for the information guys. What about a Golden Bee? Do they run inverted?
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Babe Bee is always clear anodized or silver aluminum.
They have a 5 cc tank with no tubes sticking out, and the backplate has either one filler nipple and a vent, or two nipples. Since fill/vent is topside, well, it normally only runs with the backplate upright.
Black Widows and Golden Bee's have their obvious color. However, they hold 8 CC's, and the backplate has no vent/fill.
Instead the vent/fill tubes are on the tank. One from topside going down to just above the inside/bottom of the tank. The other enters the tank from below, and stops just inside/below the top of the tank. Basically, the tubes are set up like a wedge tank.
As long as the fuel pickup tube makes it to the outside, and low on the tank, the BW, GB backplate could possibly be in any of the four possible positions (needle upright, to either side, or down).
For a while, I ran my Golden Bee sideways with the cylinder out starboard, and the needle to inboard. No upside down landings were going to take out my glowplug or needle!
The tank tubes still went up and down.
Oh, and those fill/vent tubes...ISTR they fall to one side or the other of the venturi. You want them inboard so they don't syphon fuel through the whole run. If they are outboard, they are syphoning-out fuel longer.
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If you set up with the tubes horizontal and cap the outboard one while flying, you get a uniflo setup!
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never thought about that ,good idea
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So do I understand correctly that the Golden Bee won't run inverted without clocking the tank or some other modification?
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The Golden Bee will run inverted just like the Black Widow. Nothing needed to do in order to do so. These engines though don't really tolerate inversion for too long regardless of how they're designed. If you want to go inverted, it's best to do so early in the flight when the tank is full. The need to flip upright can become readily apparent when needed. Outsides, and other maneuvers involving inverted can be obtained but sustained inverted flight for too many laps can starve the engine of fuel and it can quit.
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The Golden Bee will run inverted just like the Black Widow. Nothing needed to do in order to do so. These engines though don't really tolerate inversion for too long regardless of how they're designed. If you want to go inverted, it's best to do so early in the flight when the tank is full. The need to flip upright can become readily apparent when needed. Outsides, and other maneuvers involving inverted can be obtained but sustained inverted flight for too many laps can starve the engine of fuel and it can quit.
If you make sure the wpickup hose is exactly on the horizontal centerline of the tank, the engine will run inverted as long as you want.
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All the tanked bees are essentially the same. The fuel ports are either in the back or the tank, with a fuel pickup hose that must be located where it will do the most good.
Go here
https://coxengines.ca/engine-and-fuel-guides.html
Look at this document
Gibeault Mouse Race Program
The only difference is he shows making a metal pickup tube, and not the stock one. The other modifications are optional. Good pictures with descriptions are hard to find is all, the other user guides are at that link too.
Phil