jabiru fuel cap

[BrendAn]

the fuel cap on my lsa 55 appears to only lock in place with the pressure of the o ring holding it. is this correct or am i missing something.

 

[lyle janke]

 hi 

 yes  that is correct . if you want a security measure  then replace the wing nut assy with a security torque bolt of same thread then it is impossible to get cap from the filler neck 

 lyle

[BrendAn]

2 hours ago, lyle janke said:

 hi 

 yes  that is correct . if you want a security measure  then replace the wing nut assy with a security torque bolt of same thread then it is impossible to get cap from the filler neck 

 lyle

Excellent. Thanks.

[RFguy]

Be aware the o rings go bad pretty fast. Suggest replacing if more than 5 years old, and replace with the Viton orings, they'll retain their resistance to the fuel a little longer. mine were all crap when I got my jab (at 9 years old) 

 

[Old Koreelah]

Relying on that big O ring to keep your fuel cap on seems dodgy. I’ve got an extra layer of security: a strong metal bar that hinges over the cap.

[RFguy]

ROFL they wont fall out, they are in deep and there is minimum wind load on them, the screw causes the o ring and assembled ot expand. OK there is NO WAY they come out  accidently

[BrendAn]

6 hours ago, RFguy said:

Be aware the o rings go bad pretty fast. Suggest replacing if more than 5 years old, and replace with the Viton orings, they'll retain their resistance to the fuel a little longer. mine were all crap when I got my jab (at 9 years old) 

 

will  replace with viton. thanks rf

[facthunter]

While the "O" ring has integrity, the whole thing is safe. Surely you check it every time you refuel?  Nev

[BrendAn]

40 minutes ago, facthunter said:

While the "O" ring has integrity, the whole thing is safe. Surely you check it every time you refuel?  Nev

yes, once i have a licence and use the plane.  its a bit of a project nev. hope to have it ready to fly by christmas. 

 

[Old Koreelah]

9 hours ago, RFguy said:

OK there is NO WAY they come out  accidently

Glen I’m sure they’re great, but history is full of exceptions to the NO WAY rule.

One of those exceptional scenarios is if I land on a draggy surface like a thick crop. If the mains dig in she tips over. That delivers a large hydraulic pulse load to that O ring. That one reason my tank vents are large bore, and take leaking fuel to wingtips.

[facthunter]

Nice to think an inverted plane won't leak fuel. Fuel slosh effect can be reduced by baffles.   Nev

[BrendAn]

22 hours ago, Old Koreelah said:

Glen I’m sure they’re great, but history is full of exceptions to the NO WAY rule.

One of those exceptional scenarios is if I land on a draggy surface like a thick crop. If the mains dig in she tips over. That delivers a large hydraulic pulse load to that O ring. That one reason my tank vents are large bore, and take leaking fuel to wingtips.

plenty of jabs have tested that without losing fuel caps.

[RFguy]

they dont lose fuel caps. dont worry about it. 

[facthunter]

The wing isn't far from the Cof G or any likely pivot point.   Nev

[Bruce Tuncks]

I don't like the vent pipe on my Jabiru, especially the enlarged bit at the top which looks like a casting and it contains the forward-facing vent holes.

If this top bit were sawn off and the pipe given a low-drag shape, a lot of drag would be saved, plus a bit of weight. The effective height of the vent would be reduced a bit , by the amount of the cast bits, which are about 30mm I think.

Has anybody done some drag-reduction work on these?

[RFguy]

Consider that Jabirus have very few  or zero fuel delivery issues (apart from running out !).  It's unheard of.

Bruce if you let me know the height and diameter, I'll calculate the horsepower cost.

[Old Koreelah]

Bruce I’d hasten slowly with these vents. It’s too easy to bugger up a functional vent, and the drag difference might be bugger all. (I’m more concerned at the risk of vent location to your eyes). I fluked a good setup with my first (thin vinyl hoses to top of wingtips, with lots of tiny vent holes drilled thru. The vortex airflow suited the vent site.
Years later, trying to improve streamlining, put in larger vent hoses, exiting just under wing tip. They caused no end of problem, until it was pointed out me that the vortexes were sucking air out of the tank.

[Bruce Tuncks]

Thanks guys! I will send a pic of what i"m talking about soon, together with measurements for RF guy.

Once I read that 1/4 inch diameter tube had the same drag as a Libelle wing ....  wow.