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Building Tips and technical articles. => Building techniques => Topic started by: Phil Goldberg on August 06, 2015, 12:35:05 PM
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I am trying to find the best way to mount my fuel tank on a new Ringmaster that I have built. Seems there are several ways however each has strong points and flaws. Any ideas on the subject will be appreciated. Thanks
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Phil,
I had the same question a while back, but for a Flite Streak. Maybe it was about tank size?
Anyway, I soldered four "L" tabs on to the tank with four "T" nuts on the outside of the fuselage for the receiving end of the fastener. I think I went with 4-40? I'll know when I mount the tank.
You can egg holes for adjustment or shim under the tank.
This was one of the ways I was told to do it.
Good luck with whatever way you decide.
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My three preferred methods are:
- Tabs on the tank like Charles does. Your screw holes will eventually waller out and you'll need to firm them up with epoxy.
- The smallest "cupholder" hooks at the hardware store (they're about 3/8" across). Hold the tank on with "rubber bands" made from bicycle inner tubes or long skinny O-rings. "Real" rubber bands will turn to goo. I screw the hooks in, then take them out and daub them with epoxy, then put them back in -- this seems to make a nice permanent installation.
- On my "serious" planes with plastic tanks I make a plywood or aluminum base with slotted holes. I bend it or use spacers so that the rear is kicked out about 1/4" to insure fuel draw, and I hold the tank on with plastic cable ties. If you bend one up out of aluminum you can make it just wide enough to cradle the tank & hold it firmly up and down. The "waller out with time" effect still holds -- epoxy is your friend.
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I prefer the long, slotted tabs on the fore and aft ends of the tank. No melting/broken rubber bands, adjustable tank height.
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Phil,
You better be able to purchase your rubber bands wholesale,
you're gonna need a bunch of them. LL~
Hard to believe in R/C we held our wings on with rubber bands on some models.
I had a Warefarer bipe. Both wings had rubber bands. Retrimmed the thing every time you put any wing back. n~
No, I paid retail for my rubber bands.
The tank on the Mig-3 is held on with 3M 1/4" fine line tape. See photo.
I'm kidding! Just kidding.
Couldn't use rubber bands, no room for cup hangers at the rear. But I did consider it.
So, I went with soldered tabs again on the Mig-3's tank.
Washers over the tabs and this install should be fine. Can be adjusted also, egging and shims.
I don't expect any issues.
I believe Bill's tabs are available from Brodak. Nice start, you don't have to make them.
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I use nylon zip ties.
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Once you get the tank where you want it, do away with all the other junk and use silicone bath tube sealer. It does away with stresses that cause leaks with mechanical fasteners. In lieu of rubber bands use fish line or some other thread product hot-glued in place to back up the silicone.
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On my profiles I use 3/16 dowels on the inboard side of the nose. Angle them toward the center of the doubler. Just make sure that your rubberbands are long enough to reach both sets. It ain't pretty, but neither is my flying.
Steve
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I gave away my carefully sculpted epoxy
and plywood tank mount at Brodak's ,so
I needed a quick and dirty replacement.
It doesn't look very nice but it took minutes
and has lasted thirty flights and one contest
so far. (Got a 2nd).
Nothing fancier than just a piece of common
coraplast. I cut slots for adjustment but it's
so easy to make, I'd find the tank level and
cut to that.
Cheers!
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Here's an overkill on steroids profile tank mount.
Trying for a system with better adjustability than the coat hanger and rubber band mounting, and more robust than solder tabs vulnerable to failure from vibration, resulted in this proof of concept mount using whatever materials were in the shop.
The weather has been too stormy to try it out, but it can be pared down a lot using 1/16" angle aluminum and made with a saw and file.
Or better yet, as Paul suggested, get rid of all the junk and just silicone it in place!!
Ara
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You can call that overkill if you like, but someone did a nice job working that aluminum angle.
Aluminum is light.
Looks like a fine way to get the job done to me.
AND, it's adjustable for various size tanks!
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I prefer the long, slotted tabs on the fore and aft ends of the tank. No melting/broken rubber bands, adjustable tank height.
This is how I did mine,, the tabs soldered onto the ends of the tanks with 4-40 machine screws into either blind nuts,, or threaded inserts,, very adjustable,, durable and simple,,
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I'm not at home and can't access any photos or measure anything; so I can only describe what has worked well for me.
I also hold the tank on with rubber bands stretched over the tank, but between self-made hooks. This is better than using hardware you can buy, because it's ultra easy and cheaper, and the hooks can be shaped into better shapes for easier attachment of the bands.
Drill two holes (probably 3/32" dia) above and two holes below the tank location, so that bands will not interfere with tank tubes. Bend small lengths of matched-diameter wire into "J" shapes and use a dremel tool to notch them in the straight lengths that go into the holes. With a file, remove sharp edges that can snag the rubber bands. Then insert epoxy into the holes and push a "J" piece into each.
I recess my tanks and use shims above or below to adjust height, but on models with flat attachment, I've just made balsa cradles whose centering places the tank at an intended height.
This takes so little time and cash that I just don't worry about it. I like the slotted angle pieces too, but don't trust my soldering, preferring the replacable bands.
'never a problem...FWIW.
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You can call that overkill if you like, but someone did a nice job working that aluminum angle.
Aluminum is light.
Looks like a fine way to get the job done to me.
AND, it's adjustable for various size tanks!
Charles
They worked quite well but in an unexpected way. I machined the mounts with 1/8" angle because that's all I had in my box 'o' junk, which turned out to save the plane.
The angles were mounted on an old, many times rebuilt Buster with a honkin' Fox 36 shiney case plain bearing. The old Fox promptly shook the lock nuts loose and was wedged on by the bolts only and one loose nut. Those beefy mounts held the front end together despite the vibration and saved the plane and engine.
Ara