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100LL and the Rear Window

JerryG150

JerryG150

Well Known Member
It was bound to happen ... I knew it would. This morning I was standing two feet away from the lineman who was adding a few gallons of 100LL fuel to my RV-12 and after I just told him to fill slowly because of everything I've read on VAF, when ... you guessed it ... the 100LL shot out of the filler pipe and splashed a bit on the back window and ran down the side of the fuselage.

I immediately wiped it ... but the window, near the edge by the fuel filler immediately showed some one directional spider web stress "superficial cracks" in the window. Before that happened, I have to admit there were some other one directional web patterns in other areas of the back window. Before the spillage, I figured they were stress spider web "superficial cracks". The gas just added to the "design", unfortunately.

I guess I (we) just live with 'em. I hope the "stress or gas superficial cracks" don't get worse. I'll be sure to keep my eye on 'em.

Thanks again to all you RVators on Facebook who are voting for my grandson to win an Ipad2. You can vote daily (Click Here to vote)... he's the 4 year old holding up a piece of bacon.
 
Jerry, do you have the screws that hold the window to the turtle deck skins tightened? A knowledgeable source told me they should be loose enough to turn with very little resistance to avoid cracking the lexan. Sorry about the spill. I plan to make an apron of sorts to cover that area while filling. I think Tony T. has a thread on this.
 
Van's can correct this

So there are 134 reported RV-12s flying and maybe only 5 or 10 crazed/replaced rear windows - so Van's knows that this part of their kit could be improved.

So why not use the better material in the latest kits? If it costs a little more than I, for one, would pay the difference. Or, if/when it happens to me, I can replace my rear window with the better material that one vendor has. But, why not get it right from the start?

Come on, Van's - bend a little - even purchase and stock the better rear window from the guy who offers them and give us who have not yet installed the window a choice or which window to buy? That way, I for one, would not have to install two rear windows in order to get one that wouldn't craze. In my opinion, the rear window that is sold with the kit is just an accident waiting to happen.
 
Just go ahead and put the good one in. If it turns it into an EAB, so be it, your choice. Plus you can get a tinted one that way too.
 
You sure it's crazing and not just the remnants of the 100LL after it dried? Pledge makes great polish to try and get the crazing out if that's the case.
 
Personally I NEVER let a lineman service my '12. I know how easy it is to get that burp of gas back up the tube. When I first started fueling the airplane, I did have a couple of minor spashes on the window. :eek: I expected the worst, but no ill effects. This may possibly be due to the protective film left behind by Plexus, the product I use to clean/polish the windows. I know it leaves a very slick coating that nothing much sticks to. Just a thought, for what it's worth.
 
The back window is structural in that it supports and stiffens the side skins that it is attached to. Acrylic might not be strong enough for this application.
Joe Gores
 
Crazing ...

I used Plexus also ... maybe that's why the "crazing" was so limited. Tomorrow, I'll see if I can "wash" that crazing off ... I should be so lucky. Like I reported before, I have other "stretch" marks where the back window flex's to the max.
 
"stretch marks"

The "stretch marks" on my rear window were there before my plane was ever gassed up or flown. They haven't yet gotten worse with 20 hours on the Hobbs. They are in the major curved portions of the rear window itself. They haven't expended with flight.

Those small additional one directional craze marks near the gas filler haven't expanded overnight. I haven't tried to clean them off yet ... if they can be cleaned off as suggested in a previous post. I'll let you know if they "wash off'.
 
Just for general knowledge sharing.

Yesterday I turned over 330 hours on the blue RV-12. During that time I have filled the tank with 100LL countless times and I'm ashamed to say I still, every now and then, geizer it. And boy does it come out. The lexan rear window has been drenched in 100LL quite a few times and I have noted no crazing whatsoever. I do have some minor stress cracks around some of the screw heads and I keep an eye on them. But they don't seem to be propogating.
 
MLock said:
....I'm ashamed to say I still, every now and then, geizer it. And boy does it come out. The lexan rear window has been drenched in 100LL quite a few times....
Click to expand...

Been my experience that in the long run it's absolutely unavoidable with present-day fuel hoses and nozzles. It's bound to happen. Nothing to be ashamed of.

And Murphy says that it'll happen most on a windy day, to ensure that the fuel gets dispersed as broadly as possible over you and the airplane.

Dave
 
Mr. Murphy has crossed my path too many times. Actually, I kinda like the smell of 100LL when it gets on your clothes and everywhere else, but I sure don't like how it tastes.
 
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