Re: (Spirit of St. Louis pic)
The immense size of Spirit's tank was really made clear in this EAA Webinar video (after about one hour in):
http://www.eaavideo.org/detail/video...-in-solidworks
Re: (Spirit of St. Louis pic)
The immense size of Spirit's tank was really made clear in this EAA Webinar video (after about one hour in):
http://www.eaavideo.org/detail/video...-in-solidworks
We all know that aviation has inherent risks. I don't believe any of the fuel systems in light aircraft are designed to purposely impact solid objects. As one who has experienced such a situation, with 25+ gals just behind the panel, I believe it is the luck of the draw. (or maybe the grace of God) My fuel tank split open, the lines were torn loose, and miraculously, there was no fire. I think is equally important, to reduce or eliminate any spark producing appuratus, prior to impact, either by design or physically. (Master)
That's quite a gash, there, PB339. If you wouldn't mind describing your airplane, I'd appreciate it.
The aircraft was a Starduster Too, with a 220 Cont radial. The fuel tank was right behind the firewall, and carried 28 gals.
Yikes!
I would be very, very hesitant to move the fuel tank from a position other than what is specified in the plans.
The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.
Aviation is about risk management. There are a very large number of airplanes flying with fuel tanks in front of or behind the pilot. The number of crashes is small. The number of crashes that result in a fire is smaller. The best plan is to avoid crashing. Would we like there to be no accidents of incidents? Of course. But those folks who suffer from the illusion that the aviation accident rate could be zero are best advised to keep their flying hours to zero.
Moving the fuel tank in a proven design requires re-engineering the entire design. And plastic fuel tanks are heavier and have somewhat less capacity if they are sized to fit in the same space as the original AL tank. The good folks at Sonex started from scratch to incorporate plastic tanks in their design. Changing an existing design is generally more work. Best to follow the plans for what you have or build a Sonex. And keep your brain ahead of the airplane to avoid a crash.
Best of luck,
Wes
Last edited by WLIU; 03-24-2018 at 05:46 AM.
PB339, that is one beautiful airplane. I got to briefly take the controls of one over twenty years ago. For a guy that was flying a Cessna 140 at the time, it was an exhilarating twenty minutes.
What I've learned so far is that, once a mold has been created, generating copies of the fuel tank (14 gal) is very inexpensive (perhaps as low as 50 dollars). The particular plastic recommended is Cross-linked Polyethylene (XLPE).
The major cost is in fabricating the mold -- a few thousand dollars (rough quote of 5000 USD). So, this is only economical if a few builders of the same aircraft were to share the expense.
Taking into account the responses in this discussion thread, I feel comfortable proceeding with the fuel tank's designed location aft of the firewall. I'll make a final decision on tank material a little farther down the road.
It has been helpful to have the input of experienced builders. Many thanks.
Food for thought: For many years the fuel tanks in pick up trucks were behind the seat. Occasionally, due to poor maintenance & not replacing old hoses someone smoking might have a fire but you rarely heard about it. Then, for "safety", Chevrolet (and GMC) started putting the fuel tanks under the front of the bed on the driver's side. If a Chevy truck made during those years was t-boned on the driver's side they frequently caught fire. In later years the fuel tanks on all trucks were moved to be inside the frame rails.
I would think that a fuel tank located inside a steel tube fuselage would be inherently better protected from rupture in the case of a crash. In the design I am working on (on hold due to family reasons) I will probably put the fuel tanks in the wing roots but inside a steel tube structure connecting the spars to the fuselage.
One other thing to add...
The Aluminum used to make tanks is not 6061....
It's 5051... a softer aluminum...It "Gives" better..
.
Gotta Fly...