Rebuilding a Black Widow, mouse racer style.

Good work Rusty,

Can't wait to see the results.

I am going to do the same thing, next years tach race is going to be interesting.

yup, I have 1.75 gallons of the Sig Champ left and it's some pretty gooey stuff. Once that is used up, I am going to mix up some O'donnell 30% offroad I still have unopened and "adjust" the oil level. See if I can't melt my fingernails off and fling pistons thru the ceiling

What is the point of having the Pylinder on its side when mounted on the tank? I have seen many do this for CL. I never tried it. I have always kept mine vertical.

Godsey3.0 wrote:What is the point of having the Pylinder on its side when mounted on the tank? I have seen many do this for CL. I never tried it. I have always kept mine vertical.

Needle protection in the event of a crash was one reason I read about.

How does that protect the needle? The needle is still pointing up while the pylinder is sideways. If anything it leaves the needle exposed.

Yeah - you can rotate the backplate without moving the Pylinder.

Godsey3.0 wrote:What is the point of having the Pylinder on its side when mounted on the tank? I have seen many do this for CL. I never tried it. I have always kept mine vertical.

Well, there are 2 reasons I can think of.

One - on a flying wing, there is no fuselage to protect the engine in the event of an inverted landing.

Two - it looks cool.... Just like the bigger planes with beam mounted engines.

The typical setup I see is where the Needle Valve is Vertical and the pylinder is horizontal. Usually to the outside of the CL ring.

CZ: Would that not leave the NV exposed in an inverted crash?

I see it as changing the balance. If you blast the thing into the ground hard, you will probably get the cylinder and needle anyways. Personal preference and/or changeing flying characteristics.

If you plug one of the vents, you can put the whole thing on it's side (adjusting the pick-up for this, of course). Then, there IS no top or bottom where the combat wing is concerned, and you can land it without damage going either way.

I do it to protect the firewall from shearing off in a high speed outside looping figure 9 when a vertical cylinder would take all of the initial impact. I have turned the NV to the inboard side, but vertical is easier to get the pickup tube in place and have it stay put, and I have a spare in the flight box. No big deal if it gets bent. The cross vent tubes are in the way of the pickup tube if you try to just rotate the backplate alone. It's easier to refuel while the engine is running when the vents are on top too.

Well, I'm off to test run the little baby. I'll finish the build report later today.

Will you be getting a video of it?

Does it also act as a weight to keep the lines tighter?

I never had issues with the lines with my Combat Wing. It has massive rudder offset. I did not even have to offset the engine. I do need to move the CG back a bit to liven it up.

Game Cocks vs Clemson.... Even in Illinois I hear that as my Step-Mother-in-Law is a Game Cock fan and my bother-in-law is a HUGE Clemson fan

Godsey3.0 wrote:Will you be getting a video of it?

It's processing now. It'll be up later this afternoon.

Godsey3.0 wrote:I never had issues with the lines with my Combat Wing. It has massive rudder offset. I did not even have to offset the engine. I do need to move the CG back a bit to liven it up.

The Satan that flies with this engine has no rudder

microflitedude wrote:Does it also act as a weight to keep the lines tighter?

Probably negligible.

WingingIt74 wrote:Game Cocks vs Clemson.... Even in Illinois I hear that as my Step-Mother-in-Law is a Game Cock fan and my bother-in-law is a HUGE Clemson fan

That was a wild game last night. Carolina won in the bottom of the 11th with one of their usual heroic catches after letting Clemson back in the game. I hope it doesn't get rained out today. It might be on national TV at 2:00, I'm not sure.

Horizontal cyl/piston is like adding a bit of wing tip weight. Also prevents flooding the motor when priming. More streamlined . Prevents ripping the firewall off in crashes. Keeps the needle away from hot exhaust gasses and prevents burnt fingers ( 180 degrees from each other).Allows the glow plug clip to hang under the plane rather on top. Most of the combat flyers went this route long ago, maybe it's a good idea.Lots of speed planes are side winders also , Maybe less drag when going roundy round.

Mike1484

cribbs74 wrote:I am going to do the same thing, next years tach race is going to be interesting.

Just my opinion, and I could be mistaken, but I don't see any way, assuming competing engines are perfectly built, that any Bee can beat a tankless engine. I don't think a Bee can possibly breathe as much air as an external tank configuration can. Have you ever seen anyone bore a hole in the back of a Bee the size of the intake on a Killer Bee? Or, on the other hand, maybe they are both limited by the reed itself. So at that level, whoever is lucky enough to have the most athletic reed wins that day.

Here is the rest of the build writeup.

We left off with polishing the crank and fitting the piston/cylinder.I had already sanded the back of the crankcase to mate with the tank. I gave the tank a buff around its mating surface too. The screw holes in this crankcase are not but a few threads deep so it's hard to get screws cut to the right size so they grip but don't bottom out. This is the cause of leaks between the crankcase and tank. I've used black Permatex to solve this problem and it works well but it's ugly. I want this to be a neat engine without shortcuts. The mouse racer article suggests using a 2-56 bottoming tap to extend the threads, since the hole is deep enough, just not fully threaded. That's dumb, Mr. Cox. So I ordered one on eBay, but it isn't here yet. As a result I cleaned my shortened screws and one by one screwed them into each hole till they bottomed. Then I counted turns as I backed them out. I went around to each hole with each screw and assigned each screw to a particular hole. This assures I'll get the most average threads hooked up, and I'll know exactly how many turns each screw can go into its assigned hole before it jams. I can count turns when I put the backplate on.
Here is the diagram I used to keep it straight when I put it together:


Now to mate the tank and backplate. I used valve lapping compound. It turns out to be too aggressive. Next time I'll use something milder. A few minutes of lapping them together and it looked good. As y'all may recall I have had trouble with the fuel tube popping out of place. But this was a new one I had run last week, and when I left the backplate on the table to dry for a couple of days, it hardened. I originally made an aluminum tube, but this looked like it would work well since it was now rigid. So I just took out the spring, cleaned it and flushed the orifices with the tube in place. I cleaned and de-linted the spring under the magnifying lamp and re-inserted it. The tube fit over the nipple pretty tight but I wanted to make sure it was tightly sealed. So I took a twist tie from my bladder supplies and wrapped it down really tight. You can see it at the base of the tube around the nipple in this picture:


This is an oldBabe Bee back so I had to plug the fuel vents. I read where Bernie posted that he uses JB Weld to plug them on the ones he modifies as BW plates. So, if it's good enough for Bernie, it's good enough for me. Besides I had to glue Holley's bird feeder anyway. So I plugged the holes with JB, and left it to cure for a day. About 18 hours later it was firm, but not hard. Here's what it looks like:


You can see it from the inside in the previous picture of the twist tie.
I gave it another day and a while to cook under my halogen work lamp and it finally hardened. I also cut a new tube to seal the needle with. I've been doing that all along. I wouldn't think of running a Bee with a spring and needle.

Next is to prep the tank. I washed out the tank and vent tubes with acetone and made sure the mating groove was clean. I cut a piece of silicon tube for the venturi gasket. I cut about 10 of them before I got it right. I need to get a piece of brass tube to use as a cutting guide in the future. The reed retainer is in good shape with no sign of having met the crank pin, so it got a good cleaning. And I test fit a new Mylar reed. I had had one jam the other day in this engine. That's what was wrong with it if you watched my "Opening Day" video. It only passed the suck/blow test in one direction on the first try. So after fiddling with it, I made an executive decision. Something I've never tried, but what the hell. I had a new steel reed so I put that in it and slipped the retainer on. It passed the test, so it got the job(another departure from Paul Gibeault's preference). I did a final lint inspection of everything and it was now ready to assemble. So I bagged it all up awaiting a fresh start the next day.

Final assembly time. I gave the screws and screw holes a final acetone cleaning and brushing and dried them out. I laid out a new clean work surface and un-bagged everything. Each piece gets one last lint check. Still no tap for the crankcase holes, but I felt I had everything ready to work. I used a toothpick to smear the crankcase threads with medium blue Permatex threadlocker. I started the screws in their assigned holes and cross tightened them until they touched bottom. I backed each one out counting the turns to make sure none turned more than I had previously noted, then cross tightened them till the snugged, and went around once more locking them down. I put a dab of black Permatex RTV in each screw hole to finish the job.
And here she is... no, this is a "He."


It's Garnet and Black. That's the color of the University of South Carolina Gamecocks, so I dubbed it the Carolina Shaker. It was also the name of a really badass Ford Fairlane 500 at the Blaney Dragstrip back in my racing days.Here's the video of the test run:


I oiled it throughout with MMO after I assembled it the night before I ran it. After mounting it, I inverted it and put a few drops of fuel inside the piston and worked it in, and did the same down the crank tube. I filled it with Glowplugboy 24% nitromethane fuel. It started on the first flip and I ran a couple of rich tanks. When I leaned it out, it ran smooth and pretty fast. The Bee crank is probably its greatest limiting factor, and I wish I had a tach. Maybe there is some audio analyzer I can download to listed to the video and give it to me in hertz. If anyone knows where I can find one, please let me know.

It won't always shut off when I pinch the vents. That's disappointing. It must be leaking between the backplate and tank. Otherwise it ran very well, and very easy to needle. I started with 5 washers with the high compression head. This head is higher compression than a Tee Dee head. I took one out and ran it. It was more difficult to needle and I had to chase it a bit, but it finally settled down and ran a bit faster than with the 5 washers. Since consistency is a must, I went back to 5 and it again ran happily.

I decided to try some SIG 35% fuel, which has never run well in the reedies. I use it for the Tee Dees and they love it. Still with 5 washers, I cranked it. The needle was different and I had to chase it a bit, but it sounded more powerful, and even through my earmuffs I could hear the wind off the prop. That's gotta be good, right. It had a throatier sound too. Boy that SIG stinks though. The 35% may run better with 4 washers, but I had had enough by then so I wrapped it up.

Later I inspected the tank and backplate for any obvious leaks. It felt like the tank may be just a red hair out of round. I did not want to take the screws out, so I stooped to uglyness. If it's leaking air at the backplate, then it can be sealed from the outside. Black Permatex to the rescue. I painted a line of RTV around the interface between the tank and backplate. Damn! But if that fixes it, it's going to stay that way. After I post this, I'm going out to the shop and see if that helped it, so I will probably know before the video is up.

I did not know Paul G. was a member of CEF before I started this, but whaddya know, he's here. Now I better make it good. Paul, if you read this, I hope you approve. Or if you need to add some criticism, I'll welcome that too.

And that's all I have to say about that.

Sounds as good as it looks Rusty. Did it seal?

cribbs74 wrote:Sounds as good as it looks Rusty. Did it seal?

Nope. In fact it wouldn't needle at all. I could run the needle out to the last thread and it wouldn't run rich. It wouldn't develop power except in surges regardless of the needle position. That's got to be loss of crankcase pressure. When my tap comes, probably tomorrow, I'll put new screws in it and a bead of sealer around the back of the crankcase. This is the exact problem it had before I rebuilt it. I hope that fixes it or I might have to put it in the big vice and smash it flat!

Also, once again after running the SIG fuel the glowplug wouldn't light until I sprayed it off with alcohol, and it has a white haze covering the coil. That never happens with the Nelson plug in the TD.

Mercy, these things can be aggravating. I think I'll take a break and fly the Bean today, if the field dries and the temp warms up.

RknRusty wrote:

cribbs74 wrote:Sounds as good as it looks Rusty. Did it seal?

Nope. In fact it wouldn't needle at all. I could run the needle out to the last thread and it wouldn't run rich. It wouldn't develop power except in surges regardless of the needle position. That's got to be loss of crankcase pressure. When my tap comes, probably tomorrow, I'll put new screws in it and a bead of sealer around the back of the crankcase. This is the exact problem it had before I rebuilt it. I hope that fixes it or I might have to put it in the big vice and smash it flat!

Also, once again after running the SIG fuel the glowplug wouldn't light until I sprayed it off with alcohol, and it has a white haze covering the coil. That never happens with the Nelson plug in the TD.

Mercy, these things can be aggravating.

Rusty,

Time to bring out the magnifying glass and start looking for hairline cracks. Sorry it went south! Keep after it.