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by GallopingGhostler Thu Sep 12, 2024 8:32 pm
Cox Engine of The Month
Baffling a Bee?
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Baffling a Bee?
Over in the Main forum of Stunt hangar, Dan McEntee posted about Larry Renger's American Aircraft Modeler magazing article in the For the Tenderfoot series where he talks about getting started in aerobatics. In the article Larry talks about making a baffle in the Bee tank to prevent sloshing.
Has anyone done this? How exactly did you make the baffle, as in what material and how did you affix it to the tank?
The Nonplussed Mark
Has anyone done this? How exactly did you make the baffle, as in what material and how did you affix it to the tank?
The Nonplussed Mark
batjac- Diamond Member
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Posts : 2361
Join date : 2013-05-22
Age : 61
Location : Broken Arrow, OK, USA
Re: Baffling a Bee?
Hey Mark , that sounds unnecessary to me and look like it would keep fuel at the bottom from getting to the intake hose . I looked on SH but don't know my way around good enough to find the original listing
getback- Top Poster
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Re: Baffling a Bee?
I find it would make little to no difference. Insuring the engine is leak free by doing positive and negative suction tests in my opinion is more important than what I see in that diagram. For instance, a chicken hopper tank is to the side of a main tank. The outside atmospheric pressure insures that the smaller hopper is always full and the pickup is completely submersed due to a top and bottom encapsulating the pickup. This isn't the situation here. I would also have to assume that there's holes in what he's suggesting to be a baffle. If you swing a bucket of water in a circle, the water climbs up the wall of the bucket. He also suggests maneuvering, the Bee backplate isn't designed for inverted maneuvers which can be done but that baffle wouldn't be the solution. What I feel would help immensely is to uniflow the tank which I've never done. I believe I saw a picture that Paul Gibeault posted of a racer which had a Bee on the nose. If memory serves me correctly, the additional pipe was added for uniflow which makes sense. When your racing, you need fast reliable starts. You don't want to the engine to get too hot and heat soaked when it stops. Uniflow would provide a reliable steady run from start to finish and it wouldn't go leaner as the tank depleted.
Ken Cook- Top Poster
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Join date : 2012-03-27
Location : pennsylvania
Re: Baffling a Bee?
If you have any of the old metal back plates, they do have baffles in the casting.
Unfortunately, I don't have any photos of the old back plates.
The newer plastic backplate (ones without fuel nipples on the back) have baffles injected into the backplate.
That also adds strength to the plastic back plate. (a little)
Take a close look at the backplate in the photo below.
It is the ones that would be on the Black Widow, Golden Bee, Baby Bee ---- the engines used for U-control.
The back plates that don't have them are the ones that use the fuel nipple on the back plate to fill the tank.
Example would be the Cox Texaco back plate.
The only thing I found out with the backplates with the "baffles", it made it a little easier to place the end of the fuel line against the upper side of the baffle so it was easier to know that the fuel line was going to be on the side of the tank when I assembled everything back together.
Downside ---- always found just a drop of fuel left inside the tank. (Below the baffle.)
Unfortunately, I don't have any photos of the old back plates.
The newer plastic backplate (ones without fuel nipples on the back) have baffles injected into the backplate.
That also adds strength to the plastic back plate. (a little)
Take a close look at the backplate in the photo below.
It is the ones that would be on the Black Widow, Golden Bee, Baby Bee ---- the engines used for U-control.
The back plates that don't have them are the ones that use the fuel nipple on the back plate to fill the tank.
Example would be the Cox Texaco back plate.
The only thing I found out with the backplates with the "baffles", it made it a little easier to place the end of the fuel line against the upper side of the baffle so it was easier to know that the fuel line was going to be on the side of the tank when I assembled everything back together.
Downside ---- always found just a drop of fuel left inside the tank. (Below the baffle.)
sosam117- Diamond Member
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Join date : 2016-03-23
Location : Suburb of Chicago, Illinois
Re: Baffling a Bee?
I really don't consider that a baffle on the plastic backplates, just more or less a resting fence for the fuel pickup.I have some metal versions which also incorporate that into them. I've used small pin drills and placed holes to wire tie my pickup to it to keep it put in the desired location. Larry Renger by the way designed that particular plastic backplate. The early version was very short lived because without all the additional reinforcement, it was distorting under the pressure of the case screws. A baffle in my definition would be such a device that would run from front to back in it's entirety with the exception of some holes through it to allow fuel to get through.
Ken Cook- Top Poster
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Re: Baffling a Bee?
I think for most of us, if the Bee hiccups or burps a little in maneuvers, we just take it in stride, continue flying, rest, refuel, repeat.
Personally I never thought of doing any stunt competition with my half-A's ever. I just guess it is what perspective one is coming from. Even in RC, I just simply relocated the tank pickup to the bottom of the tank and continued on. Planes ran fine short of flying inverted except in a loop or barrel roll. I did that on my Q-Tee with a Golden Bee, and after a couple seconds inverted, the engine quit as predicted.
Never had any problem or indication that required baffling.
If one needs to make a custom tank, perhaps a separate one for a tankless reedie, Medallion or Tee Dee, then may be that is the time to entertain baffling.
Personally I never thought of doing any stunt competition with my half-A's ever. I just guess it is what perspective one is coming from. Even in RC, I just simply relocated the tank pickup to the bottom of the tank and continued on. Planes ran fine short of flying inverted except in a loop or barrel roll. I did that on my Q-Tee with a Golden Bee, and after a couple seconds inverted, the engine quit as predicted.
Never had any problem or indication that required baffling.
If one needs to make a custom tank, perhaps a separate one for a tankless reedie, Medallion or Tee Dee, then may be that is the time to entertain baffling.
GallopingGhostler- Top Poster
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Re: Baffling a Bee?
I am flying RC not CL but tend to agree the baffle, if intended to prevent fuel from sloshing in the tank, should run in the full tank length, not just in the depth of the backplate.
Pictured here is my early production BW disassembled, showing short ribs in the backplate. The maximum they would be good for is to keep the fuel line tip fixed in a side bent position for clockwise or counter clockwise CL flying, in my opinion.
Pictured here is my early production BW disassembled, showing short ribs in the backplate. The maximum they would be good for is to keep the fuel line tip fixed in a side bent position for clockwise or counter clockwise CL flying, in my opinion.
balogh- Top Poster
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Re: Baffling a Bee?
Sorry but there are already venturi tubing, fuel tubing and screws inside of fuel tank. How fuel slosh in tank? Those tiny backplate baffles can prevent fuel sloshing?
Levent Suberk- Diamond Member
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Re: Baffling a Bee?
I do believe the shelf/ledge whatever is just for C/L fling and that it was intended tp hold the fuel hose to the side .
getback- Top Poster
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Re: Baffling a Bee?
getback wrote:I do believe the shelf/ledge whatever is just for C/L fling and that it was intended tp hold the fuel hose to the side .
Right, I think so. Other than this what about red delrin TD fuel tanks? I don't think there are any baffles inside of them.
Levent Suberk- Diamond Member
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Re: Baffling a Bee?
getback wrote:I do believe the shelf/ledge whatever is just for C/L fling and that it was intended tp hold the fuel hose to the side .
I have to agree with you getback.
Those little "fences" make it easy to keep the fuel line (pickup) on the side of the tank when reassembled.
As seen in my photo and the other photos with them there.
And the backplate without the "fences" is intended for R/C or FreeFlight engine flying
as the fuel line (pickup) needs to be at the bottom.
sosam117- Diamond Member
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Re: Baffling a Bee?
Even without the little fuel line mount stops, the nearest tank mount screw will hold the line at say, around 105 degrees, which should still be fine for CL. I don't think the fuel level is exactly vertical during normal flight. In any case, the amount of fuel missed is so small, that such benefit is small any way.
And, did the earlier Bees of the 1960's have those mount stops? I'd have to disassemble one of my .049's to check, but on the earlier ones, I don't think they were there.
And, did the earlier Bees of the 1960's have those mount stops? I'd have to disassemble one of my .049's to check, but on the earlier ones, I don't think they were there.
GallopingGhostler- Top Poster
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