Aluminum fuel tank

[kmacht]

For those making aluminum tanks have you thought about the safety impacts? An accident makes the aluminum tank much more likely to puncture or rupture than the rotational molded tanks do. Post sonex accident fires are pretty rare for a reason. Aluminum works fine in a wing but right behind a hot engine and sitting over your legs isn't where I would want a gas leak after an accident.

Keith
#554

[DCASonex]

Raised front end of my tank with 1/8" plastic strip on top of firewall angle and made new deeper filler box that also incorporates an overflow catch trough and drain. Without the changes neck would have rested on sharp edge of filler box PM me with e-mail address if want photos and drawing, but rotational molded tanks are like`snowflakes, -- no two are alike.

David A.

[Area 51%]

Just got back from Oshkosh (Sonex proper) where a discussion of their tanks ensued. A couple of new-on-the-shelf tanks were measured and found to be distorted at the fuel fill end to the same degree as mine. Kerry confirmed they all come from the same mold, from the early black tanks, to the current. Either the problem has manifested itself recently somehow (possible), or no other builders over the last decade noticed or cared. (Doubtful)

According to Kerry, I am the only builder to report back to the factory with any issues with the tank whatsoever. In this case, however, the squeaky wheel will not receive any grease. A list of builders who had, at least, the filler box issue, might have prompted a closer look at the tank supplier's wares and kept our projects moving forward instead of cutting apart a complicated and tedious component (the upper firewall fill box) to "fix" yet another aspect of the build.

I can't help but wonder, because of the problems I'm encountering and the fact that they were about to introduce the B model, if I received left-over, returned, faulty parts in my kit. Can't explain it any other way. I feel as if I'm building the prototype-stable-mate to the factory jet to be called the "Sub-Standard".

Heating of the tank to reshape was approved, but not successful, as 1/4" of material is not easy to hide, plus it wouldn't affect/help the filler neck-to-filler box interferance.

Since the original scratch-built plans included an aluminum tank drawing with material specifications, I don't see any other direction I can take with the fuel system. Our Waiex would not be the only airplane (experimental or certified) with an aluminum tank between the engine and passengers. I only plan to land off-airport due to fuel exaustion anyway.

The only question I have at this point is the material spec. On the plans it calls for 5052 H14. The only 5052 sheet from ACS is H32 but is listed as fuel tank aluminum. Was there a spec change?

Thanks to all who let me peek under their cowls last week. (Including Sonex)

Anyone that finds themselves close to Big Pine is welcome to stop by and tell me where I've gone wrong. There are lobsters in your future.

Electric Waiex you say???????????

Randy @ Area 51%

[kmacht]

If you can get the tank to fit everywhere but the filler neck how about just making a new cutout and box in the firewall for where the neck does fit? It would seam easier than making a whole new tank out of aluminum. The other option would be to cut the next off the tank and make a new one out of aluminum or stainless. Not much fuel gets up by the neck other than when filling so it has to be somewhat leak proof but not completely like the bottom of the tank would have to be. Just some thoughts.

Keith
#554

[Area 51%]

That's the problem. There is more going on than just the filler neck hitting the box opening. The tank is 1/4in taller on the RH side than the Left. This is measured on either side of the filler spout at the corners where the tank angles down toward the longerons. This taller corner of the tank comes in contact with the glareshield even before the filler box comes into play. Pushing the tank into position without the firewall in place causes a twist in the glareshield at the front that is so severe that there is no room for the attaching angle on the RH side. (firewall to glareshield) This is all happening before the mounting straps are even tightened, which can only make matters worse. The LH side is OK.

Got word from Sonex that the H34 is an acceptable substitute, so when finances allow, I'm moving forward with the metal box. You probably won't hear any complaints about OOPs fittings from this build.

Not ready to throw in the towel just yet here @Area 51%

[Area 51%]

Well......the aluminum tank is a done deal. It fits very well, weighs 3lbs less than the plastic version, and holds 19+ gallons (slightly nose high resting on a tire).

I'ld like to post pictures, but I don't know how.

I'm sure I need some kind of anti-chafe material between the tank/straps/glareshield. Felt, I'm told, is the material of choice. Is there some special grade or composition that is especially suited for this application, or is the stuff at the craft store acceptable?

Still moving backward, but at a slower pace here @ Area 51%

[waiking59]

Here's what I used, I doubled it up, in strip in the tank, one on the strap
https://www.amazon.com/JVCC-FELT-06-Polyester-Felt-Tape/dp/B01455QMX4/ref=pd_sbs_328_3?_encoding=UTF8&psc=1&refRID=TRCCRQ2EBVPWTA934WJS

[DCASonex]

Just used common black felt from wife's favorite fabric supply house and folded it double. Might want to double again for the aluminum tank. Few drops of glue helps keep it in place. Used same felt on top of the strip that is between windshield bow and windshield and the canopy, then used the rest to cover the glare shield.

David A.