Ready made fuel tank?

[Bry6000]

Is there an off the shelf fuel tank that will work?  Or is the point of making it primarily weight savings?

[Steve]

Is there an off the shelf fuel tank that will work?  Or is the point of making it primarily weight savings?

They can be built lighter but this one is off the shelf: http://www.teammini-max.com/online-store/fuel-tanks/

[CHARLES DEBOER]

My mimi-max tank doesn't have a sump at the rear of the tank so I lose some capacity of the tank due to the fact that I must maintain a minimum of 1/4 full.  When on final approach the fuel flows forward in the tank and could cause fuel starvation with the fuel pick-up in the rear of the tank.  Especially if I miss my approach and have to go around.  My speculation.  Has not happened to me yet.

[scottiniowa]

My mimi-max tank doesn't have a sump at the rear of the tank so I lose some capacity of the tank due to the fact that I must maintain a minimum of 1/4 full.  When on final approach the fuel flows forward in the tank and could cause fuel starvation with the fuel pick-up in the rear of the tank.  Especially if I miss my approach and have to go around.  My speculation.  Has not happened to me yet.

A quick CAD drawing can show exactly at what angle and level this would occur, but Charley, I would agree with you... a single outlet tank can get a bit scary.  A small header tank can really help here..but then again that is more weight-more fittings.  But most header tanks were done for a reason (safety) 

good to calculate these things.  I prefer, fore and aft fuel sumps per tank.

[John Reinking]

Good thoughts, Scott.   Question though, a header tank would provide the safety margin of fuel tanks that don't have the sump capability wouldn't it?   Could you elaborate on this for us less experienced builders?   Thanks Scott.   John / Woodinville, WA

[scottiniowa]

Good thoughts, Scott.   Question though, a header tank would provide the safety margin of fuel tanks that don't have the sump capability wouldn't it?   Could you elaborate on this for us less experienced builders?   Thanks Scott.   John / Woodinville, WA

Ok, sorry for the delay- as stated, yes, the header tank can and would take up the time, for the "if & when" your wing tank would be un-ported during climb out or decent, with low fuel and single outlet of tank.  

To understand this visually in your mind,  picture your flat bottom tank  having 1.5" of fuel in the tank at level flight...  And then take said tank and tilt it to the angle of decent or climb out.  At what point or angle does the 1.5" level no longer cover the outlet fuel port?  While I could do the math for you, I think you will have a greater appreciation  using your kitchen table and a large sheet of poster board, with your tank dimension drawn out...  then til fore and aft and redrawing where Level Low Fuel would be in relation to your outlet hole.

So first argument is always-

•  "but I won't fly with that low of fuel"   Never say never, but when your going around a rain event at 60 mph, and suddenly find yourself in the air 40 minutes longer than planned, all things become a concern.
•  - "but the angle is not that much"  Kitchen table work will prove or disprove what your max angle can be... Thus your minimum fuel with one sump. (while at it, figure out two sumps-hint, more than twice of one)
•  - "but, a header tank is to big"   We are not talking about 8 gal per hour fuel burn, you can proportionately size your tank..to your fuel burn and time expected.   i.e. a 15 minute leeway at 2 gal per hour, is 1/2 gal.  7.5 minutes is 1/4 gal. and so on.
•   "but I don't want to figure this all out"   Sometimes you just have to put a bit of math to it. Doesn't take much time or math. 
•   "but, if I don't do it right, it would be worse"    You got me there.   Do it right.

[John Reinking]

As always, Scott, a clear concise explanation of the tank issue.   Never expect any passengers with my DE (except my big butt!
) so I'm going with the header tank solution.   Understand fully the "keep it light" concerns  and am working to keep mine under the empty weight.   Having no experience whatever with fiberglass work and none with working with aluminum I'll probably go with a manufactured tank.

Quick question, Scott would a fuel tank "homebuilt" in aluminum and riveted at metal/metal joints work as well.   I know there are fuel sealants which can then be applied to seal those joints to assure a good seal (that's what Boeing does on their airliners (stuff smells awful in there!)   Just seeking your ideas.

Cordially, John Reinking/DE-72

[scottiniowa]

As always, Scott, a clear concise explanation of the tank issue.     Having no experience whatever with fiberglass work and none with working with aluminum I'll probably go with a manufactured tank.

Quick question, Scott would a fuel tank "homebuilt" in aluminum and riveted at metal/metal joints work as well.   I know there are fuel sealants which can then be applied to seal those joints to assure a good seal (that's what Boeing does on their airliners (stuff smells awful in there!)   Just seeking your ideas.

Cordially, John Reinking/DE-72

Thanks John for the comments.
On the tank, there are several you tubes ( I think) on showing tank building with Alum, it is simple and strait fwd.  Sizing too. There is ample room in the wing for 5 gal and a bit more if you like.  And I suppose you could rely on the fuel sealants, but you shouldn't have to.    If you do a search on Kent White a.k.a. the Tin Man, you can see how he welds the joints for a leak free tank.   This can be done even if a novice.  Or someone in your air community knows how. EAA chapters are good for this question- Who has done or can help do one? 

As for the header tank, the very simple tube ones work well.  Simply a alum tube, with caps welded on each end, with your fittings.  Light and effective. Easy to mount as well.

Hope this helps.

[Kiwi55]

I was wondering what people think of this solution https://www.summitracing.com/search/product-line/holley-hydramat-fuel-pickups
I have seen this hydramat on several hot rod or car sites. Seems to be designed for the situation being discussed here.
...Paul

[scottiniowa]

that could have possibilities these fuel pads..

[stevejahr]

Not sure how well those work... the concept has been around for awhile yet the automotive OEMs do not use them.  That makes me wonder.

The modern EFI in autos is very sensitive to fuel interruptions of any kind.  Lots of potential solutions have been used in different applications there.  One of the more interesting/capable is the "fuel pump module".  If you study these things you will find a pump immersed in fuel inside of a cup which serves as a surge tank.  Some amount of the pump output is used to feed a jet siphon pump to scavenge the main tank and fill the surge tank.  The rest of the pump output goes to the engine.  And in many applications extra fuel from the engine is fed back in a return line to the surge tank.

In some applications they use the scavenging jet pump to literally transfer fuel from one tank to another (or one tank well to another).

Now we do not generally need the 40 PSI of pressure (or more) used in these EFI systems... but they do have some worthy advantages.

I entirely agree with Scott's earlier premise about "doing the math" here though to make sure your header/surge tank has sufficient capacity to cover any unusual attitudes and durations you may reasonably encounter.