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Building Tips and technical articles. => Building techniques => Topic started by: Phil Krankowski on April 15, 2015, 02:39:04 PM

Title: Fuel tank mounting and shimming on a profile
Post by: Phil Krankowski on April 15, 2015, 02:39:04 PM
This seems like an obvious question, but in build threads I have seen a plethora of different methods.  I understand that any working system is good, and there probably is no "best"

I am finishing up a couple Flite Streaks, and have been repeatedly reading that I should be shimming the fuel tank between 1/8 and 1/4 inch, as well as mounting it securely.  I am using plastic clunk tanks on these.

I have a few ideas how to do this using a wedge and a strap.  Weight is already a problem in the nose as I will need to add tail weight already.

So, how do you do this so it is secure, and positioned properly?

Pictures please!

Thank you in advance.

Phil
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Avaiojet on April 15, 2015, 04:15:47 PM
Phil,

Can you solder?

Two different tanks done the same way. The Flite Streak tank and the Mig-3, Both profile mounted. I just soldered simple tabs. Egg the holes in the tabs for adjustment, or shims behind the tabs.

I have the tank on my Pathfinder wire tied.  n~

It moves around a bit, never in the same place twice. I still get a full run with loops, eights, wingovers plus climp and dive. But I do eyeball it kinda straight before take off.  %^@
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Russell Shaffer on April 15, 2015, 04:20:45 PM
I glue the tank to 1/8 plywood with Goop from the hardware store.  It seems to hold forever.  Then bolt or screw the ply to the fuselage - no brackets or straps to vibrate and break.  Some guys run a couple of zip ties around the tank and ply for extra insurance. 
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Steven Kientz on April 15, 2015, 04:42:24 PM
If you go old school( rubber bands and hooks) then your wedge should stay without screws or goo. Or you can glue a 1/4" square stock where the back of the tank will be. I use bamboo skewers to dowel it. If the 1/4' is too much you can sand or trim off some.
later
Steve
Title: Re: Fuel tank mounting and shimming on a profile
Post by: George Mitchell on April 15, 2015, 05:28:31 PM
http://brodak.com/adjustable-tank-brackets-end.html

Just solder to  end of tank.

George
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Avaiojet on April 15, 2015, 07:21:55 PM
Quote
Just solder to  end of tank.

George

Didn't know you could buy these from Brodak?

Nice.
Title: Re: Fuel tank mounting and shimming on a profile
Post by: ray copeland on April 15, 2015, 07:30:42 PM
Phil, if you are using a plastic clunk tank other than a Hayes tank you should have room to fit one of the bronze sintered filter pickups in it. They really help cut down on fuel foaming type runaways due to vibration on profiles! I highly recommend it.
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Phil Krankowski on April 15, 2015, 08:59:04 PM
In the stretch fuselage I went with Steve Kientz's suggestion of rubber bands
http://stunthanger.com/smf/index.php/topic,37207.msg399072.html#msg399072
I still need to shim it for height as I made the hooks wide enough to allow the tank to sit on its side if I choose to.  Yes, this is a Hayes tank.  

On the scratch built I cannot even fit the identical tank into the space, so I am not sure what to do.  I have a 90cc tank on order from Hobby King.  I have not ruled out using a metal tank.  (I also haven't checked if the ARF tank will fit, but I'd have to open and re-plumb for uniflow.)  I will consider a sintered pickup for other models.

I'm still open to suggestions.  Buying or making a tank is not ruled out, although I am far from skilled at the making of fuel tanks.

Again, Thank you for the suggestions.  I would still like to see pictures if you got them.

Phil
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Roger Vizioli on April 16, 2015, 07:25:19 AM
Phil,
I have mounted Sullivan plastic tanks/w clunk on the inboard side of the profile fuselage on Ringmasters and Twisters.
No problems that I remember (@ my age!   LL~).
Roger V.
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Phil Krankowski on April 16, 2015, 07:28:55 AM
Phil,
I have mounted Sullivan plastic tanks/w clunk on the inboard side of the profile fuselage on Ringmasters and Twisters.
No problems thatI remember.
Roger V.

I am considering that.  It will simplify fuel line routing with the remote NVA on the LA25 too.

Phil
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Dane Martin on April 16, 2015, 09:49:23 AM
All of my profiles, with the exception of two, the tanks are mounted inboard. I get a lot of compliments on my engine consistency.
Title: Re: Fuel tank mounting and shimming on a profile
Post by: Avaiojet on April 16, 2015, 10:56:27 AM
There are places where you can buy rubber bands in different colors.