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Engine basics => Engine set up tips => Topic started by: Tom Perry on March 01, 2008, 04:15:41 PM

Title: Newer Black Widow Modification.
Post by: Tom Perry on March 01, 2008, 04:15:41 PM
Has anyone any information on modifying the newer Cox BW for stunt use?  Can the tank and or backplate be rigged to operate like the older one with the tank vent to allow for normal and upside down flight?  can the tank be modified to accommodate the vents as in the older one?  if so what do you use to hold and seal the vents?   ???
Title: Re: Newer Black Widow Modification.
Post by: Bill Little on March 01, 2008, 05:44:37 PM
Ray (minnesota modeler) has posted pictures of a set up that uses notched fuel tubing that goes around the tank and the notch is at the bottom.
Title: Re: Newer Black Widow Modification.
Post by: Tom Perry on March 02, 2008, 06:23:23 AM
Ray (minnesota modeler) has posted pictures of a set up that uses notched fuel tubing that goes around the tank and the notch is at the bottom.

I've seen that but was wondering if there was a way to duplicate the older style.   AP^
Title: Re: Newer Black Widow Modification.
Post by: john e. holliday on March 02, 2008, 06:59:40 AM
Do I like did on a couple.  Drill holes to fit tubing, kind of a force fit.  Then J-B Weld inside as well as out.  DOC Holliday
Title: Re: Newer Black Widow Modification.
Post by: Tom Perry on March 02, 2008, 07:33:51 AM
Do I like did on a couple.  Drill holes to fit tubing, kind of a force fit.  Then J-B Weld inside as well as out.  DOC Holliday

This is what I was looking for.  What did you do about closing the vents on the back plate?  I will probably sub the metal backplate from a baby bee and will drill out the venturi.  I sent Ray Stone a couple of back plates some time ago. maybe he will chime in here?   :)
Title: Re: Newer Black Widow Modification.
Post by: kenneth cook on March 02, 2008, 05:17:31 PM
            Tom , I tried using the older vented stunt tank with the metal baby bee back plate. I used very small fuel tubing with dowels jammed in the ends to cap off the baby bee fuel nipples. This didn't work too well for me. The tubing would always pop off for starters and I don't think it was completely air tight. I never got a full run from this. I think Jb Weld would do a better job of blocking those nipples. I saved a lot of the backplates from the plastic model engines similar to those on the production engines. I found using these with a small tank gave me a whole lot less trouble. Some of the needle valves on some of my backplates had some very fine threads which suited bladder usage. Ken
Title: Re: Newer Black Widow Modification.
Post by: Joey Mathison 9806 on March 02, 2008, 07:13:31 PM
tom you may try to soft solider the baby bee holes
Title: Re: Newer Black Widow Modification.
Post by: minnesotamodeler on March 17, 2008, 07:09:06 AM
Hi Tom, sorry I just now found this, I don't usually check all the forums.

If you just cap one of the vents after filling, it will work sort of like a uniflo, and won't lose any fuel inverted since it's drawing air through the single vent.  The notched fuel line looping around the bottom really didn't work too well, hard to keep it on the vents. Best is to use an external tank of your choosing.  You can drill a hole through the side of the integral tank and install a fuel line to the nipple, or buy a Cox production engine ($8?) and use its backplate.

--Ray
Title: Re: Newer Black Widow Modification.
Post by: Paul Smith on March 17, 2008, 07:38:36 AM
Another painless way to deal with it is to rotate the backplate so the NV and vents are inboard, and of course, make sure the pickup is still outboard.

You'll have to hold the plane kinda funny while you're starting it, but it will be perfect in the air.