stunthanger.com
Engine basics => Engine set up tips => Topic started by: Mike Greb on January 07, 2020, 09:08:09 AM
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I have recently found that the Hayes tanks have been taken over by MECOA.com The 3 oz tanks have been a favorite of mine and others for many years. The attached picture is of the setup I use on sport planes with the molded in vent set to the outside. In this configuration the vent functions as a uniflow vent and there is very little mixture change throughout the run. Fueling is a bit tricky as the model has to be pointed down to fuel, and let the tank vent air through the needle valve .
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I like these tanks too for Samuel's planes. I always buy the 3 and 4oz ones when I see them at swap meets. I just scored 8 of them NIP at my local hobby shop for $1 a piece. The owner buys out estates and put all the small stuff on a bargain table. I go in every couple weeks just to root through the boxes.
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Even though I'm pretty much exclusively building full-fuselage planes these days -- woo hoo!
I like your uniflow idea. You could take it a step further by drilling that nipple out to 1/16" and putting in a length of 1/16" brass tubing (K&S makes it, although you'll probably need to get it from Amazon). That would put the uniflow outlet at the back of the tank, where it belongs.
With most plastics if you drill a hole with a size X drill the plastic will flex, and the result will be just enough undersized that a size X music wire or tube will be just the right fit to put the tube in by hand and have it stay forever without leaking.
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the uniflow will work just as good at the front of the tank as it will at the rear. also keeps air bubbles away from the feed tube
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Yes the Hayes tanks are on the MECOA website, click on the Hayes logo. When they set up the FP20 with this tank the mount it with the foot to the bottom so the tank is narrow and tall. They plumb it with conventional clunk and vent (non uniflow style). I have tried it the way you have it shown, I drilled out the top vent and fished in a 1/16" piece of tubing to be the uniflow. It worked but not the greatest.
Best, DennisT
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Thanks for making us aware of this. I ordered some right away.
Allen
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I put them with the foot down and close off the middle nipple after filling. The nipples are pointed forward. Works fine for me on profiles.
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I'm glad someone challenged the "vent tube to the rear" concept.
One school of thought is that while the flight forces do cause line tension, and the fuel goes to the outside, the fuel vent, or fuel pickup, can work at the back, middle or front of the tank.
With a pickup in the traditional rear location, canting the rear of the tank out is not a bad idea. One plane I have is arranged with about 1/4" cant, measured as the rear of the tank away from the profile fuse. It works well, a little better than a similar plane with a tank mounted flush to to the profile slab.
YMMV. $0.02,
Peter
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I have a question. What does cant mean and how is it done?
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When I estimated 1/4" cant, that was a little high. The Cardinal profile I fly has a 5/32" cant. Works well.
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Thanks for the reply about the cant. I think I will try it. Thanks again.