The inevitable fuel spill disaster
Posted: Mon Apr 15, 2024 7:53 pm
by 13brv3
Greetings,
I’m sure this falls into the category of those who have, and those who will.
I was thinking of flying a round trip cross country flight later this week, so I filled the fuel tank rather than leaving it around 13 gal like I usually do. This proved to be a fatal mistake, at least for the windscreen and canopy. The last part filled so fast that it caught me off guard, and overflowed. It’s hard to estimate how much spilled, but at least a few ounces. Naturally, it got on the windscreen, which immediately crumbled. It ran down the glareshield to the sides, and since it’s a taildragger, it ran downhill toward the rear. I immediately looked at the right side where the canopy is hinged, and it didn’t look like it ran that far down, though there was some on the left side. I wiped both sides and went back to the front. I was thinking that I was lucky it was the relatively easily replaceable windscreen, and not the PITA canopy when I heard some popping. It seems a tiny bit of fuel must have seeped between the canopy and frame on the hinge side, then wicked it’s way to the rear of the hinge screw line. About 1/3 of the screw holes now have cracks extending up a few inches, and I’ll be surprised if the rest don’t by the time I get back out there.
I’ve absolutely hated this fueling situation, and it shocks everyone who sees it. It was just a matter of time before this happened. I’ve filled it so many times that I wasn’t being careful enough, and now I’ll pay for that mistake with a new windscreen, canopy, and unpleasant labor (I hate trimming canopies).
I do try to look for the silver lining:
#1 is a HUGE one, and that’s the fact that it happened in my hangar, and didn’t strand me at some other airport.
#2 is that will be that I can finally fit the Peter Anson canopy latch. I’ve had it for a year, but it was going to conflict with the rivet locations in my canopy frame, so I didn’t want to try to install it. Now I’ll have no excuse, and it will actually be a nice improvement.
#3 is the temp, which is pleasant now, so not freezing or stifling heat.
#4 is that I will probably go ahead and fit the fuel return Rotax wants. I’ve been doing without it, and it makes the fuel pressure kinda wonky at times. I might even move my fuel flow meter to below the tank rather than after the gascolator. Since the interior already stinks like gasoline, why not.
#5 is an assumption, and that’s being thankful that I can actually get a canopy. That wouldn’t be the case for a lot of planes out there.
Of course the down side is the hassle, and cost. I ordered a spare canopy and windscreen since there was a discount for the spare, and since it all has to go truck freight. All total, my momentary lapse of attention will will cost me about $1500.
Rusty (have I mentioned I hate the fuel filler location)
Re: The inevitable fuel spill disaster
Posted: Mon Apr 15, 2024 9:55 pm
by Bryan Cotton
Yikes! That sucks.
Re: The inevitable fuel spill disaster
Posted: Mon Apr 15, 2024 10:41 pm
by Scott Todd
That’s horrible! I can’t begin to tell you how careful I am when refueling. I always put a towel around the opening to catch any drops. I also stick the tank before and make sure to fill it a gallon short. I haven’t ever pushed the range so this hasn’t been an issue so far.
I’ve heard it isn’t as bad with Avgas. What fuel were you using?
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 12:33 am
by 13brv3
93 octane non-ethanol auto fuel. I wouldn’t be surprised if the additives in the auto fuel are harder on the plastic, but 100LL is harder on the engine. I’m usually really careful, and have probably fueled the plane close to 100 times, but it just takes one momentary attention lapse. I’ll try to find a way to insure that the canopy can’t be damaged again. The windscreen is pretty easy to replace.
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 9:00 am
by Onex107
I lost the windshield in Onex 107 after filling the tank using 5 gal cans that had leaky spouts. Lesson learned. I bought a battery powered transfer pump with a short hose that had overflow protection in the spout. It would shut off if fuel reached it. I could set the 5 gal tank on the wing and pump 5 gal in 3 minutes and not worry about overflowing. And no drips.
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 10:05 am
by Area 51%
It was my understanding that plexiglass is quite tolerant of hydrocarbons. Polycarbonate…not so much.
Permatex used to offer a plastic cleaner that was available at almost all F.B.O.s. 2-4-D I believe. It was petroleum based and did a fantastic job on plexiglass without damage.
I’d be surprised if fuel was the culprit behind the canopy cracks.
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 10:43 am
by 13brv3
Area 51% wrote:I’d be surprised if fuel was the culprit behind the canopy cracks.
Fuel was 100% certain to be the cause. I don’t think fuel would have harmed the acrylic if it spilled on a spot in the open with no edges or drilled holes. In this case, it found screw holes, and a cut edge along the hinge line.
Had I closed the canopy rather than leaving it open, the fuel likely wouldn’t have made it to the acrylic. Of course pumping fuel through your windscreen does make you want to open the canopy to vent out the fumes. There has to be a better solution to this.
As for auto shutoff pumps, I might have to revisit that. I used to use battery powered pumps made for 5 gal jugs, and they worked well, but slowly. For the past year, I’ve been using a fuel cart that I made with a 12V pump, and aluminum tank. The pump came with a non-shutoff nozzle, and I immediately changed it to an auto-shutoff. Unfortunately, that wouldn’t start pumping uphill when the hose was empty. I got tired of fighting that, and went back to the standard nozzle.
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 6:21 pm
by lakespookie
I wonder if there is a way to modify a canopy and make a square aluminum tray around the filler so you dont have as much risk when filling.
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 8:59 pm
by 13brv3
lakespookie wrote:I wonder if there is a way to modify a canopy and make a square aluminum tray around the filler so you dont have as much risk when filling.
It’s definitely something I’m looking into. Anything you put there blocks some forward vision though, so making a pan large enough to contain a spill will be an annoyance. There’s also the problem of sealing around the tank neck, and vent fitting, though that’s doable.
A while back, I printed a funnel of sorts that I figured I’d take if I ever had to fill the tank at another airport, but I’ve never actually used it. I may revisit this as well, but add an o-ring to the bottom of the funnel that seals well to the fuel filler neck. As it is now, if you overfilled, it would leak around the neck of the funnel.
I did more inspecting today, and I believe there are cracks where fuel could have never touch. I’m starting to believe strong vapors are enough to start a crack, particularly for a hole that’s under any stress already. I’ll have lots of scrap canopy material to test that theory some day.
Good news is that Sonex is expecting to ship the canopies Fri, via truck freight. I’ll probably have them middle to end of next week I imagine.
Re: The inevitable fuel spill disaster
Posted: Tue Apr 16, 2024 10:04 pm
by Bryan Cotton
The Onex looks similar to the Sonex-B design. I had shown an Australian builder what we did on the A model for a catch can, and he came up with a similar concept for the B model. Watch from about 2:50 below.
Perhaps a catch can like that, and a cover for the top would make it better. For our Waiex I carry one of these in the airplane:
https://www.harborfreight.com/solid-non … 65565.html
That rubber sheet will protect from a splash but not a flood.
Here is the catch can thing I built:
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 12:07 am
by 13brv3
Bryan Cotton wrote:The Onex looks similar to the Sonex-B design.
So the B models have that same horrible through-the-windscreen fill hole? That’s really sad to see, as it’s the single worst thing about the Onex. The pan is about what I was thinking, but of course I already have a vent line close to the cap, which complicates things. I need to add another port for fuel return as well. Not sure what I’ll do yet, still thinking.
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 12:30 am
by daleandee
13brv3 wrote:
Bryan Cotton wrote:The Onex looks similar to the Sonex-B design.
So the B models have that same horrible through-the-windscreen fill hole? That’s really sad to see, as it’s the single worst thing about the Onex. The pan is about what I was thinking, but of course I already have a vent line close to the cap, which complicates things. I need to add another port for fuel return as well. Not sure what I’ll do yet, still thinking.
You make me smile and hug my Model C (Cleanex i.e. Corvair powered model A) sonex airframe. The original models had concerns with the fittings possibly spinning if overrtightened but work arounds were found (don’t overtighten the fittings). The fuel filler is still close to the windscreen but a small safety area exists. Having the fuel filler hole through the windscreen is something that would be very hard for me to deal with and I’d have to devise another method.
I do have a fuel cart with a shut off nozzle and it pumps fuel at a rate of about 5 gallons in less than a minute. When fueling at airports with full service I always ask the attendant to allow me to fuel the plane and I’ve never been refused that request. These airplanes are such great designs but there are a few things that could be improved upon IMHO. This is one of them …
Dale
3.0 Corvair/Tailwheel
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 12:35 am
by WaiexB22
As I was working tonight I was thinking about how much I don’t want to deal with this and how much I agree that the fuel fill location just plain sucks. Here is what I was thinking:
I have been considering adding a 5-7 spun aluminum auxiliary fuel tank to the area right behind my seat. I’ll be running mogas and having the capacity on a cross county would be great, but in reality most of my flying is for fun for an hour or two. I had pretty much talked myself out of it for weight and balance and unnecessary complexity; however, I have chosen a REALLY heavy propeller…so i was thinking…if I add a real fill port for the aux tank the on the turtle deck or aft sidewall I would have a really convenient fill location that would eliminate my possibly of destroying the windscreen. If I use a fast enough transfer pump I could feasibly transfer from my aux tank to my main while taxiing. The vent for my main tank is routed overboard and the aux tank would too. This would also reduced fuel vapor in the cockpit after refueling (those with flying planes chime in if this is actually a problem).
I have my tank out right now to install the new straps and work on the firewall. While the tank is out I can easily add a fill for the aux tank.
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 8:33 am
by BobDz
WaiexB22 wrote:As I was working tonight I was thinking about how much I don’t want to deal with this and how much I agree that the fuel fill location just plain sucks.
Exactly what I was thinking. One concern I have is that adding more "stuff " reduces the usable weight. Lots to consider. I’m considering an aluminum tank. If I do an aluminum tank, a different fill site would be great. Also considering a heavier engine. Then a fuel tank in the aft fuselage makes sense. An aft fuel tank filling a header tank has the potential to make for interesting in-flight weight and balance calculations. Easy enough to determine prior to flight. Another reason to play with Excel.
This could be fun!
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 9:59 am
by 13brv3
When I first put all this together, I considered using one of the extra fittings on the gascolator as a fill port. I figured it could be run to a valve behind an access panel on the cowl, then use a 12V transfer pump to fill the tank. On the rare occasion that I’d fill the plane at another airport, you’d still have to use the normal fill port.
The biggest problem with this is being able to see how much fuel is in the tank when you’re filling it. Fuel gauges aren’t the best, and if your 3rd wheel is in it’s natural location that throws the readings off when you’re on the ground. Removing the fuel cap sort of defeats the purpose. Of course eventually it will squirt out the vent, but that’s certainly not the best method.
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 10:13 am
by Bryan Cotton
If you are building an aluminum tank you can make a filler neck like the A model, and the stainless box that goes around it.
We generally read the fuel level on the ground and add a specific amount of gallons, rather than watching. Two up, we can’t take full fuel. It also works if you want to go full fuel when flying solo.
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 11:15 am
by DCASonex
The “A” series Sonex was much better in this regard, do not know what they were thinking when they put the filler through the canopy on the “B” series and Onex. Added an overfill catch and drain to my “A” series that does not need a positive seal to the tank.
The Sonex canopies (at least on the “A” series are curved on the sides then held straight by the aluminum frame. This leaves the material under stress on the inside right where the screw holes go. Mine cracked during the night following its installation. Replaced it with a Todd’s Canopy (unfortunately no longer available) and bonded in place. 12 years no problems.
David A.
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 11:18 am
by BobDz
David
Do you have a picture of your overfill catch?
Thanks
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 11:43 am
by Bryan Cotton
BobDz wrote:David
Do you have a picture of your overfill catch?
Thanks
It probably looks a lot like the one in the “Waiex 191 fuel catch and drain” video I posted on page 1. I copied what others had done.
Re: The inevitable fuel spill disaster
Posted: Wed Apr 17, 2024 12:26 pm
by Onex107
A few years ago we did a fuel, windshield test. We took a piece of windshield and duncked it in fuel. No effect. Then bend the piece and put some stress on the surface and drip a few drops on the surface and you get cracks. I presume if our windshields were composed of flat plates we wouldn’t have a problem. All the fuel is doing is relieving the stress of the bending.
Re: The inevitable fuel spill disaster
Posted: Fri Apr 19, 2024 7:15 am
by DCASonex
Photos and drawings of my modifications to the A series Sonex fuel filler box can be found on the Sonex Foundation website, under fuel vent and fill box about 2/3rds of the way down here: https://sonexfoundation.com/the-amsler-files.
David A.
Re: The inevitable fuel spill disaster
Posted: Fri Apr 19, 2024 7:53 am
by BobDz
Thanks for that link David!
Excellent info!
Re: The inevitable fuel spill disaster
Posted: Thu May 02, 2024 9:27 pm
by 13brv3
Back from the dead. It only took 2 weeks and $1300 to correct a momentary lapse in attention… I considered some sort of box around the fill cap, but I don’t want anything blocking my view permanently, so I put it back like it was. I’m working on an improved version of the fuel fill funnel to keep fumes and any overflow out of the cockpit.
Along the way I added a fuel return to the tank to hopefully cure some really odd intermittent low fuel pressure readings. Rotax “requires” a restricted fuel return to eliminate any vapor lock, and I do think that was the cause of some of my low pressure readings.
I also took the opportunity to install the Peter Anson canopy latch. It required some modification because I put rivets in the way of the block. I’d recommend getting one of these latches when you’re originally building the canopy frame, because it’s about 1000 times better than the stock arrangement on a Onex. That’s his fuel cap too, BTW.
Naturally, the weather is forecast to be crappy for the next week. And because I can never say it enough, I HATE fitting canopies!
Re: The inevitable fuel spill disaster
Posted: Wed May 08, 2024 4:34 am
by WesRagle
Hi Guys,
Catching up on reading.
Onex107 wrote:A few years ago we did a fuel, windshield test. We took a piece of windshield and duncked it in fuel. No effect. Then bend the piece and put some stress on the surface and drip a few drops on the surface and you get cracks. I presume if our windshields were composed of flat plates we wouldn’t have a problem. All the fuel is doing is relieving the stress of the bending.
And here is my experiment along the same lines.
https://sonexbuilders.net/viewtopic.php?f=58&t=5813&hilit=stressed#p43915
The (partial) solution I am using. A 15 gal hand crank fuel transfer tank. I insert the spout and hold it in place while I crank with the other hand being careful not to over fill.
I agree that this is a horrible place for the fuel fill. I understand wanting to make the build easier, and to reduce parts count, but …
Wes
Re: The inevitable fuel spill disaster
Posted: Wed May 08, 2024 6:37 am
by sonex892.
Fueling even the A model sonex is not ideal. I mostly use mogas and would sometimes spill fuel when pouring from the 20 litre container.
Here is how I now syphon fill. The larger tube extends to the bottom of the container. Blowing into small tube pressurises the container to start the syphon. Its not real quick but I have never spilt fuel when using it.
Re: The inevitable fuel spill disaster
Posted: Wed May 08, 2024 6:59 am
by Skippydiesel
Random thought;
Why not have a section (larger than the usually small hatch) that hinges back towards the canopy, staying almost vertical. The hinge line could be made splash proof and the large “door” would protect the canopy from almost every possible fuel spill/splash/spatter scenario.
Down side would be the risk of opening in flight but I am sure some fail safe latching mechanism could be applied.
Note: My Sonex centre tank, is filled vie either wing tank, so no fuel close to canopy.
Re: The inevitable fuel spill disaster
Posted: Wed May 08, 2024 9:55 am
by 13brv3
I seriously considered making a metal box that enclosed the fuel cap, but in the end I just couldn’t accept having something like that permanently blocking part of my forward view. The plans call for an aluminum cover for the fuel hole in the windscreen, but I like the clear polycarbonate cover for obvious reasons. I stole that idea from someone, maybe Wes?
I wish I knew how much fuel spilled, but I can’t see how it was more than a few ounces. The problem is that the curved glareshield channels the water to the left and right, where it runs along the side toward the back of the windscreen on a taildragger. A little liquid made it all the way back to the rear of the windscreen on the left side, and at least a few drips ran off the rail. I never saw liquid fuel on the right side where the canopy hinge was, but some must have made it there, and wicked under the hinge. I don’t think brief fuel exposure would hurt the Lexan or Acrylic in an area where there are no edges or drilled holes.
For the first year or so, I used these pumps- https://www.amazon.com/gp/product/B010GNM7H4 They’re a little slow, but they work well, and have an auto shutoff. I’d never trust that, but it was nice as a backup, and I did test it to make sure it worked. Later, I wanted something faster, and with a good filter, so I put together a fuel cart with a 12V pump, powered by a Dewalt 20V pack via 12V adapter. This works really well, but there’s no auto shutoff. I did try an auto shutoff nozzle, but it just won’t prime and pump fuel uphill to the tank. If you point it into the tank opening to get it started, then it will work, but that was (or seemed like) too much effort.
I’m closing in on a final fuel funnel solution, maybe finished later this week.
Re: The inevitable fuel spill disaster
Posted: Wed May 08, 2024 11:57 am
by Jester504
For my -A I’m going to make a plastic sheet with a hold in the middle that is slightly smaller than my fuel cap. It’ll cover everything around for 2-3 feet around and live in the cargo compartment. I might also permanently attach a funnel to that hole so there is literally nowhere for fuel to go except in the tank or on the ground.
Re: The inevitable fuel spill disaster
Posted: Wed May 08, 2024 6:35 pm
by Skippydiesel
13brv3,
Nice neat refueling set up.
On the matter of pump priming - from the photo it looks very like your pump is a centrifugal type. Centrifugal do not easily self prim when mounted above the liquid source. You have two choices;
[list=]For best scavenging (removing all fuel) mount the pump below the tank. Mounting at the same level will also work but if pump is stopped/shut off when the fuel level is low it may not self prime, unless you fit a non return valve.
Fit a posative displacement pump. I use a cheap copy of a high volume Holly - its brilliant! - self primes and will easily lift fuel to the tanks on high wing. Down side is that you can not use a tap/shut off nozzle on the delivery end without fitting a pressure relief bypass circuit.[/list]
Re: The inevitable fuel spill disaster
Posted: Thu May 09, 2024 12:08 am
by 13brv3
Priming might not have been the right word for it. The pump came with a standard nozzle that doesn’t have any auto-shutoff feature. It works perfectly with that, and fuel flow seems instant. The picture actually has the auto-shutoff nozzle that I bought for it, but then abandoned. The way the auto-shutoff nozzles work is really clever, but seems to require some liquid pressure to allow the auto-shutoff to disengage. I’m going to revisit this and try to make it work.
Re: The inevitable fuel spill disaster
Posted: Thu May 09, 2024 12:45 am
by WaiexB22
Skippydiesel wrote:
Note: My Sonex centre tank, is filled vie either wing tank, so no fuel close to canopy.
What pump(s) are you using to transfer? How fast does it transfer?
Re: The inevitable fuel spill disaster
Posted: Thu May 09, 2024 3:54 am
by Skippydiesel
A single Transfer pump, Facet Posi-Flow PN 60303. 7-10 psi,129 L/hr = 2.15L/min. It’s slow but adequate. There is a wing tank selector valve - Left, Right, Off, that must be turned to the “active” tank.
I have 30 L in each wing tank and 35L in the fuselage tank. I mostly transfer in the air but on occasion, top up the fuselage tank on the ground and then fill both wing tanks.
My son has made me a semi automatic fuel transfer system (can be turned to manual) that works very well. I just select the wing tank I want to use, press the Auto Fill button and the Transfer pump starts. The Auto Fill works on fuel level and on time. If its taking to long for the fuel to get to the preset 35L level, it will time out and stop the pump.
My fuel return line, about 7L/hr, goes to the fuselage tank.
I can use my Boost pump ( Facet Cube PN 40135, 4-7psi, Flow 121.13L/hr = 2L/Min) on any of the three tanks for TO/Landings, however it’s simpler to just use the fuselage tank.
Re: The inevitable fuel spill disaster
Posted: Thu May 09, 2024 2:56 pm
by 13brv3
Skippydiesel wrote:13brv3,
On the matter of pump priming - from the photo it looks very like your pump is a centrifugal type. Centrifugal do not easily self prim when mounted above the liquid source.
The Fill-Rite folks are very quick with replies to questions. Priming is indeed the issue. They said the automatic nozzle requires 4psi to actuate, and the centrifugal pump can’t generate that much pressure if it’s lost prime. I do have a few options to get it working, and I’ll definitely be reinstalling the automatic nozzle.
Re: The inevitable fuel spill disaster
Posted: Sat May 11, 2024 12:29 am
by 13brv3
I think I’ve pretty much settled on the new fuel funnel. It seals to the inside of the tank neck with an o-ring, and should dump any overfill or spill harmlessly on the cowl. Now I just have to be vigilant about using it.