Black Widow setup

John
Thanks, I looked before starting the thread. I'll look again.

Duke,

I just went through this same problem with a BW. Ran like crap in the air, but fine on the ground.

The problem more than likely is a leaky tank.

First thing I would do is pressurize the tank. Close off the NV plug the bottom vent with your finger and then feed air into the fill tube using a syringe and a piece of fuel tube.

You will more than likely see air bubbles coming from the crankcase gasket, venturi hole, tank backplate or screw holes. It could be all places or only one.

Ron

To fix.....

Use a throwing dart shaft o-ring to seal the venturi. Lap the crankcase flat and install a new gasket. Use a piece of dental floss to seal the tank to backplate and use either floss or RTV to seal the tank screw holes.

John
I found one by Rusty "Restered & Merged-My Freshly Rebuilt Black Widow", sound likethe right one?

The stunt tank doesn't do inverted terribly well as it will expose the fuel pickup which is lower than midway in the tank (this is so the tank more-or-less can run out.) As a general rule do all your inverted laps in the first 1/3 of the tank. Going briefly inverted like in a loop or figure-8 is usually not an issue till the end of the tank when you ought not be doing stunts anyways.

If you use RTV or similar sealant, get an aluminum safe product. Sealants that are not aluminum safe will erode the aluminum. With such thin sections you can get holes formed by the sealant eroding the aluminum. (I have seen the results on cars and boats from the wrong sealant being used, holes through much thicker aluminum parts.)

Phil

something else to look at
https://www.coxengineforum.com/t753-the-revised-2011-gibeault-mouse-race-program

duke.johnson wrote:John
I found one by Rusty "Restered & Merged-My Freshly Rebuilt Black Widow", sound likethe right one?

Yep that's the one Duke

There's probably some useful info in that thread. I thought I had done one as a more organized project build with videos, but I don't see it.

No matter, most of my information came from the Paul Gibeault Mouse Racing article. I illustrated some of it and made a couple of videos. In the end I had that BW turning a 5x3 Top Flite prop just over 20,000 RPM. It's now on a Blackhawk Li'l KomBat plane hanging in my shop. I cranked it last week for the first time since last Winter and it still runs fine and steady, though a bit less than 20k.

EDIT: My other thread. This is the one you're looking for.
https://www.coxengineforum.com/t1695-rebuilding-a-black-widow-mouse-racer-style

RknRusty wrote:There's probably some useful info in that thread. I thought I had done one as a more organized project build with videos, but I don't see it.

No matter, most of my information came from the Paul Gibeault Mouse Racing article. I illustrated some of it and made a couple of videos. In the end I had that BW turning a 5x3 Top Flite prop just over 20,000 RPM. It's now on a Blackhawk Li'l KomBat plane hanging in my shop. I cranked it last week for the first time since last Winter and it still runs fine and steady, though a bit less than 20k.

EDIT: My other thread. This is the one you're looking for.
https://www.coxengineforum.com/t1695-rebuilding-a-black-widow-mouse-racer-style

This was very helpful, maybe a little over my head. I should be able to figure it out though. It might have made me a little interested in mouse racing, I'd heard of it but didn't know what it was. Thanks

If you just want a reliable flier then you can just do what I suggested in my earlier post and it will be a good solid runner. Inverted flight with a black widow is always a risky proposition. Usually by the time I muster enough courage to flip it on it's back, I have already run too much of the tank out.

Ron

I think the best run to be had on the Black Widow is losing the stock tank and going with a hard tank. I have a few Black Widow and Golden Bee tanks which have a hole drilled through them for running a remote tank. Unfortunately, this ruined the tanks. I wasn't responsible for this doing, I just saved the tanks and use them accordingly. This allows my broken (cracked around the screw area) tank banks to be utilized. One could also go the product back plate route which I prefer and use a remote tank. I also like the fact that I can press a 128tpi needle valve assembly into the product backplate which I generally drill out the venturi area to 11/64". If the metal tank is carefully inspected for leaks, proper size plumbing, and pickup is located internally correct all problems yours experiencing should not be an issue. Many of the Perfect tanks have extremely small tubing which impedes proper fuel draw and it's also brass. Tubing that's used on the construction of these tanks aren't seamless, and the tubing Perfect used is very susceptible to splitting the length of the tube not to mention the "Green Death". This problem is quite apparent with the pickup tube which isn't soldered internally at the proper location in the tank. The tubing now acts like a tuning fork and work hardens itself into failure. Ken

No one has put their two cents in about running the Black Widow on pressure. Any thoughts?

JPvelo runs a reedie on bladder pressure. He has a 128 tpi NV and it runs great. Not as powerful as a Tee Dee but it hauled his Li'l Satan around pretty well. fly my Brodak kit Baby Streak on a Tee Dee and I can't imagine using anything less. Click the Youtube button under my avie to see what it flies like, if you are interested.

I watched the video, nice job! The Baby Flight Streak plans I have are for a reed engine not a Tee Dee. I thought about changing the nose for the tee dee. I've changed a bunch already as I've started the scratch build. I've caused myself a little trouble and it's slowing me down a bit on the build. I have a BW tank with a hole in it to hook to a remote tank, I could try that and I'm not sure what a 128tpi needle is for the bladder.

You can get a fine thread needle valve from Texastimers.com
It can be press-fit into a backplate such as a Killer bee plate or any other with a wide venturi. Or you can rig it up as a remote valve with a little more work.

It allows the fine adjustment to needle the engine under pressure. The regular NV is too coarse to get a reliable setting. Texas Timers sells all of the tubing and fittings necessary to make and run your bladders.

Here are two videos I made showing how to make bladders and run them.
https://www.coxengineforum.com/t3317-pressure-bladder-how-to-videos-parts-one-and-two

Here is the one that goes on a Tee Dee

RknRusty wrote:You can get a fine thread needle valve from Texastimers.com
It can be press-fit into a backplate such as a Killer bee plate or any other with a wide venturi. Or you can rig it up as a remote valve with a little more work.

I've heard these valve assemblies are the cat's a** for a Medallion retrofit.
A must for bladder use.
I stuffed one in a OK Cub .049b that was impossible to start. Bingo!
It's the same set up found in the humble postage stamp
backplate.
Bob

these work on the black widows backplate?

duke.johnson wrote:these work on the black widows backplate?

No, on the plastic horseshoe ones.

duke.johnson wrote:these work on the black widows backplate?

Yikes Duke.
I've been mulling that question for a while.
This is regarding the tank backplate.
I'm thinking of cutting the needle seat off and
pressing the threaded part into the backplate, relying on the
stock backplate needle seat.
In essence recreating the KustomKraftmanship backplate assembly.
I might have to sacrifice a backplate or two to do it.
Trial and error don't ya know.
Bob

Like Bob says, it's been done, but it's probably a pain in the ass to get the old one out of a metal backplate and fit the new one in. If you are determined to use a Black Widow with the backplate in place, it would be easiest to get a plastic backplate and jerk out the NV and press the new one in. Or if you switch to a killer Bee backplate and use your Black Widow front end, it would be very easy to do. Press the new one into the KB plate and JB Weld it in place and you've got an engine ready to fly.

Another option is, if you have an old spare tank that you don't mind boring a hole in, put that one on the BW and run a fuel line from an external tank or a pressureless party balloon straight through the hole to the nipple in the backplate. Then if you ever want to restore the BW to its original form you'll have the original tank to put back on it. It won't perform as well as a pressurized feed with a wide venturi, but you can still call it a Black Widow if that's important to you. Bernie sells all sorts of tank replacements, some without fuel vents that you could punch a hole in.

Sorry to beat the dead horse, but. If I buy one of these killer bee backplates there's a way to take the old needle seat out and insert the fine theard needle seat. Then I can run the black widow front end on it with pressure and I'm good? And thanks for all the help guys.

Exakerly!
JB Weld it in place and give it plenty of time to harden. It'll be a fine runner, and lined up next to any ordinary BW, it'll blow the flame off of it. The reason I know this is I watched and posted with JPvelo when he was doing the same thing. And when he posted a video of himself cranking it to fly his Li'l Satan I almost dove under the desk. The sumbitch runs like a scalded dog. He used all of the Texas Timers bladder tubing and fittings.

JP spread it out over a few threads, but they all have "Li'l Satan" in the title and are dated within the past few months. It's worth looking up his threads while he was learning to use it. He has switched to a Tee Dee for more pull and performance now, but it was strong and reliable for a reedy.

There is some learning curve getting the hang of using a bladder fed engine, but once I learned, I'll never use a regular tank again. I think I posted the link to my two bladder how-to videos in your thread already. If not, they are stickeyed in the Modeling forum.

Rusty
As always you are tons of help. And the boys learned what a scalded dog was I know cox has the KB back plates, who has the fine needles? And how do you get the old needle out without breaking the brand new backplate? I've used the bladders when we fly combat and have watch your video (mostly to see who you were), you did a great job. I'd like to get a few reedies flying better. should I do this to the baby bees also?

Duke,

The NVA can be pressed out numerous ways. I used a philips screwdriver about the same diameter as the NVA and pushed it out. A small pin punch would be better.

It only pushes out in one direction. Press out from the needle end I believe.

Ron