GallopingGhostler

Recently I pulled a rather decrepit looking Cox .049 Babe Bee off my son's unfinished Sterling Beginners P-47. It was a "barn find" that he and a friend discovered out in a field they traversed a while back. Now he's grown and married but still have the plane.

The aluminum was corroded and the steel cylinder rusted. It would turn but was dry after sitting all these years. I put a couple shots of machine oil, now it was free turning. Then disassembled, soaked in lacquer thinner overnight to remove the old hardened Castor oil on the exterior, hand sanded the aluminum with 400 grit, then polished with Mothers Mag and Aluminum Polish, put a new glow head and prop nut. Further cleaned the cylinder exterior with a Scotchbrite pad.

Replaced the fuel line in the tank. Lacking an O-ring, manufactured by a 1/64th slice of small silicon fuel line. She's worn, but still has some compression, ran it on 30%, she loves nitro. I don't know the age, but appears to be a motor of the 1960's. Needle setting is right at 3-1/2 turns. The more later one's I've used it is more like 2-1/2 turns starting, pinching off a half for peak.

She now has a new lease on life. I think I'll finish that P-47.

WoodCutter

My Feedback: (8)

Well done GallopingGhostler!!!Another classic engine rescued from the place where all the worn out toasters go...Its so nice that in this day and age where its getting harder to find airplane kits because so many want the quick ARF fix that some people still take to time to remind us all that a hobby is something that one can learn from and make new discoveries from. (not just bore holes in the sky)Plus...Its powered by good ol' glow fuel not electrons. I hope you can get it on a flying aircraft eventually.Robert

GallopingGhostler

Robert, thanks for the compliment. The electrons have their place. As a result, as the dinasaurs became birds, so has small planes have returned as park flyer electrics. BTW, a plane for that engine already exists, just needs a finish.

ZAGNUT

My Feedback: (1)

wow, haven't seen a "thimble drome" stamped tank in years!

and on polishing alum, next time try fiberglass insulation and WD-40 after the sand paper, you'll be amazed!

Dan Vincent

I noticed the Cox engine had an adapter head with standard glo plug in one of the pictures and regular Cox glohead in others.

Just curious, any estimate of how many RPM you lose with the regular plug? Does anyone have any numbers?

ZAGNUT

My Feedback: (1)

way too many variables for a simple answer....when i tried it a long time ago i lost over 2K on a black widow. K&B plug and hacked up standard cox head. after seeing that i didn't bother trying to improve it.

GallopingGhostler

Cox International estimated about 500 RPM drop. A Fuji .099S-II has a 5.5:1 compression Ratio, an Enya .09-III TV has 7.5:1; Fuji data shows 500 RPM less on the top end, so that may sound right. Of course those don't have a glow head, but the drop in compression I though might be representative. I noticed a slight drop in the Babe Bee when running it with the glow plug head, but I don't have a tach to give you specific numbers.

GallopingGhostler

One experimenter was able to get numbers similar to a button head when he shaved the bottom off the glow plug head until it had the same volume including the glow plug cavity, impressive. I don't have a several thousand dollar lathe to try that with.

aspeed

You don't need several thousand dollars for a lathe. I paid $2500 for my Hardinge Chucker lathe many years ago and made most tooling myself. Now a used lathe is more like $1000 because of all the bankruptcies. I also got a little Taig lathe at a garage sale with a bit of tooling for $250. I had to buy a 3 jaw and a taper cross slide extra, but it certainly wouldn't be thousands. Mills are also about $1000, and if you try hard you can get one with a DRO (digital readout) You may be stuck with 600 volts though and it will be heavy. Smithy has a lathe/mill combo that is fairly good for models too. It may be thousands, but it is two machines. With used machines, you can usually get your money back if you change your mind later too. Kind of money in the bank. Hard to move around though. I tapped an old TD head for short plugs, (on the lathe) and just sanded the bottom of the squishband a bit on 400 sandpaper (carefully) to bring the compression up. I haven't run it lately for tach readings. I didn't have a tach then, and I got tired of the Cox stuff. Now Merlin plugs are as cheap as a regular plug so there is no reason for conversion heads.

GallopingGhostler

aspeed, thanks for the additional info, greatly appreciated.

I was being somewhat facetious. Yes, one doesn't need a professional heavy duty industrial lathe and there are ways to shave off a little on the glow head to modify for plug or button use. For one, I have a portable drill stand for an electric drill and an electronic digital caliper. Its accuracy is sufficient that I could carefully grind off the aluminum chucked in a drill and measure.

At even say $300, one can buy a lot of glow heads before they reach that cost. For the avid home machinist, these machines as wonderful as they are, are more machine than I really need for now. They are beyond my budget abilities.

Dan Vincent

I recently saw a thread on a Dakota FF in which the owner wanted to use a Cox Baby Bee but was afraid it had too much power. This plain gloplug might lower the power enough or maybe with a reversed prop to put it in the power range of an old OK Cub or Wasp .049.

Funny, I remember wishing for more power out of .049's and now we have too much. Go figure!

GallopingGhostler

I have to agree with you there, Dan. The no longer available Cox .020 Pee Wee would have been more than enough power for the Dakota. If it weren't for the lower compression of the glow plug head, I would have just used the Babe Bee, selected a milder prop like a 5x2 or 6x2 and possibly even put it on backwards.

Yes, I remember wanting to get more power by the higher nitro content fuels for the Cox's, at least 25%, although I've used 15%.

For R/C for example, I think an Ace R/C Littlest Stick with SureStart .049, glow plug head and exhaust throttle ring would be the ticket. Haven't tried it yet, but it has crossed my mind.