metalman Posted May 18, 2013 Share Posted May 18, 2013 Hi all, I've had my plane flying for about a month, I've been running it on PULP exclusively . The problem is the fuel drains seem to leak ,I've replaced the O rings but it seems to be good for a couple of weeks then a slight drip starts( this isn't really the question although I'm open to a fix here as well) with the doors open the drips have completely stuffed the lexan! So, I need to replace them and I need to know what material will hold up ,I've been told AvGas doesn't do the same thing but I don't want to run the plane on AvGas. I also would like to use some sort of tinted stuff, so Perspex , Lexan ,Acrylic which one is the best ? Cheers Met Link to comment Share on other sites More sharing options...
Kyle Communications Posted May 18, 2013 Share Posted May 18, 2013 Lexan is the strongest. Change the fuel drains or add a pipe to divert it away. The Lexan on my pilot door was stuffed by a fuel leak. I have got a replacement to build but the Lexan is the strongest it is what they use for bulletproof glass Link to comment Share on other sites More sharing options...
dazza 38 Posted May 19, 2013 Share Posted May 19, 2013 Lexan is the strongest. Change the fuel drains or add a pipe to divert it away. The Lexan on my pilot door was stuffed by a fuel leak. I have got a replacement to build but the Lexan is the strongest it is what they use for bulletproof glass I agree, when I was a young fella, I shot a old scratched pair of my motor cross goggles which had a lexan lense with my air rifle. The pellet didn't go through. Why do you ask ? Because it was a experiment .We came to the conclusion that if a air rifle pellet didn't penetrate the lense then stones wouldn't go through either. Stones used to get flicked up by the rear tyres other bikes whilst riding. Unfortunately fuel stuffs Lexan real quick . Link to comment Share on other sites More sharing options...
old man emu Posted May 19, 2013 Share Posted May 19, 2013 Met, What is the part number of the O-ring that you used? The correct one for fuel is MS28775-(i.d.). What brand and size is the fuel drain? OME Link to comment Share on other sites More sharing options...
cscotthendry Posted May 19, 2013 Share Posted May 19, 2013 Met: If the plane is just new, you're probably getting swarf blocking the fuel drains. I had this for some time after I built the Nynja. The only real solution is to pull them out (if they're a thread-in fitting), clear the swarf and put them back in. Lexan is the toughest material for windows, but if you're after tinted, it's not available in Oz in anything thinner than 3mm thick. My Nynja has 1.5mm tinted lexan which came with the kit and is available overseas, but I was told by a couple of plastic suppliers that it isn't available in Australia for some reason. Link to comment Share on other sites More sharing options...
metalman Posted May 19, 2013 Author Share Posted May 19, 2013 Met,What is the part number of the O-ring that you used? The correct one for fuel is MS28775-(i.d.). What brand and size is the fuel drain? OME they are CAV110 1/8npt ,they came from aircraft spruce just read the blurb on them ,meant to be trouble free,,mmmm, I might have to drain the tanks if there's crap getting caught in them , I'm pretty careful with filtering the fuel going into the tanks. Link to comment Share on other sites More sharing options...
damkia Posted May 19, 2013 Share Posted May 19, 2013 Are the fill caps/ tanks venting correctly? If not then there is the possibility that the fuel is under pressure as you ascend making the drip more noticeable. As the tank gets more empty, the effect will be amplified due to the increased amount of air in the tank. Link to comment Share on other sites More sharing options...
biggles5128 Posted May 19, 2013 Share Posted May 19, 2013 Had the same issue when my aircraft was new... this is not a fix for your problem but will give some confidence that the new windows won't suffer damage while in the hangar until you have the problem sorted. The crude method I used was to cut the bottom third off a plastic oil bottle and fabricate a piece of wire to hold them as a catcher for any drops whilst the aircraft sits. 1 Link to comment Share on other sites More sharing options...
pylon500 Posted May 19, 2013 Share Posted May 19, 2013 While it is obviously better to solve your 'leak' problem, it is something that can still happen on rare occasions, and there goes another window If these are side windows, you could look into a more 'Hydro Carbon' proof material. Have a look for PET (Polyethylene Terephthalate), the stuff that soft drink bottles are made from. 1 Link to comment Share on other sites More sharing options...
metalman Posted May 19, 2013 Author Share Posted May 19, 2013 I really need to stop the fuel leaking, but with the doors open just one drip and they're stuffed again, I know Perspex is harder to work with but I've been told it doesn't suffer from fuel drips,,,I've got some prices coming back on a sheet of lexan and the same in Perspex ( grey tint) I'll also replace the damn O rings and see if I can stop that part of it. Any ideas on sourcing the drink bottle material? Link to comment Share on other sites More sharing options...
metalman Posted May 19, 2013 Author Share Posted May 19, 2013 Are the fill caps/ tanks venting correctly? If not then there is the possibility that the fuel is under pressure as you ascend making the drip more noticeable. As the tank gets more empty, the effect will be amplified due to the increased amount of air in the tank. They have little tubes poking up from the filler caps into the airstream ,like a Kitfox ,seems to work okay with a bit of positive pressure. Link to comment Share on other sites More sharing options...
eightyknots Posted May 19, 2013 Share Posted May 19, 2013 Met:If the plane is just new, you're probably getting swarf blocking the fuel drains. I had this for some time after I built the Nynja. The only real solution is to pull them out (if they're a thread-in fitting), clear the swarf and put them back in. Lexan is the toughest material for windows, but if you're after tinted, it's not available in Oz in anything thinner than 3mm thick. My Nynja has 1.5mm tinted lexan which came with the kit and is available overseas, but I was told by a couple of plastic suppliers that it isn't available in Australia for some reason. I believe you should be able to apply after-market automotive tinting to the 1.5 mm lexan. It's worth enquiring about. Link to comment Share on other sites More sharing options...
Sky Gazer Posted May 20, 2013 Share Posted May 20, 2013 Hi Matt, I'd go with the Acrylic it has a hardness factor (more accurately an impact resistance factor) of 25 when compared to glass while Polycarbonate comes up at about 44 but bear in mind that impact resistance means it is softer and deforms ( as well as SCRATCHES) that much easier. Acrylic is tintable and not too hard to work with that's what most canopies are made from anyway. Glad to see you are flying the bugger, Good luck, Pete Link to comment Share on other sites More sharing options...
metalman Posted May 20, 2013 Author Share Posted May 20, 2013 Got some prices back today, Perspex (acrylic) tinted grey in 3mm $145+tax, lexan grey tint 3mm $225+ , or I can get the acrylic in 2mm with no tint, I'll probably go with the 2mm Perspex and see how it goes( I would like the tinted stuff though) ,its cheaper ,harder and I think it'll handle the fuel drips better,no matter how good the drains are I think they'll still get the odd drip, the prices are for full sheets to so I'll have enough to do the job twice over Link to comment Share on other sites More sharing options...
Blueadventures Posted May 20, 2013 Share Posted May 20, 2013 Hi Mine has 25mm holes at the drain location so the drips drop through. Cheers Mike 2 Link to comment Share on other sites More sharing options...
metalman Posted May 20, 2013 Author Share Posted May 20, 2013 Hi Mine has 25mm holes at the drain location so the drips drop through.Cheers Mike Good idea, I think I'll take a cordless and some hole saws out on the weekend Link to comment Share on other sites More sharing options...
Yenn Posted May 21, 2013 Share Posted May 21, 2013 I had a similar problem, the drains would leak. Solved it by putting a tap above them, which was easy in my case as the tank is above the floor and the drain under the fuse. I used a 90deg turn ball valve. 1 Link to comment Share on other sites More sharing options...
sain Posted May 23, 2013 Share Posted May 23, 2013 If these are side windows, you could look into a more 'Hydro Carbon' proof material. Have a look for PET (Polyethylene Terephthalate), the stuff that soft drink bottles are made from. I thought PET was really really really not hydro carbon proof... or at least not petroleum proof. Doesn't it turn to jelly when in contact with unleaded petrol? Link to comment Share on other sites More sharing options...
eightyknots Posted May 23, 2013 Share Posted May 23, 2013 That factor would be easy to test. All you need to do is buy a bottle of Coca Cola and, after the contents have been drunk, put some petrol in it for an hour or two and see what happens to the PET bottle. 1 Link to comment Share on other sites More sharing options...
sain Posted May 23, 2013 Share Posted May 23, 2013 Well, recently I've used a PET bottle cut up to make a funnel when pouring E10 based 50:1 2 stroke. Afterwards the plastic on the inside of the funnel was semi-melted and could be scraped off. That could have been caused by the ethanol, the alcohol, the oil, or a reaction with residue left over from the contents of the bottle, or something else unknown. I poured some of the 2 stroke into what was left of the bottle and left it overnight and got jelly forming. I was also able to poke a stick through the side of the bottle with very little force. I've also worked at a service station as a young lad (wow - 20 years ago), and filling soft drink bottles was a no-no. One of the older guys had tales of a customer's bottle elongating on him (under the weight of the petrol in it) as he walked off. That was a long time ago though, and PET may not have been used for softdrink when it happened. As there were many variables in my experienced event and the rest was anecdotal I was thinking somebody might know. So - anybody with the knowing care to comment? 2 Link to comment Share on other sites More sharing options...
Head in the clouds Posted May 23, 2013 Share Posted May 23, 2013 o Perspex , Lexan ,Acrylic which one is the best ?Cheers Met Perspex is Acrylic and Perspex is just one brand name, Plexiglass is another and so on. Plain 'acrylic sheeting' will be the least costly and I've not discovered any noticeable quality difference between cheap and expensive, the most expensive might be a little better optically. Lexan is polycarbonate and also just a brand name (originally from GE), it's also usually the most expensive of the polycarbonate sheeting. Makrolon is another high quality brand (Bayer) of polycarbonate and always was available in Oz down to 1.5 or 2mm, I haven't checked recently. All polycarbonate will be affected by fuel but it's the rapid cooling from evaporation that does the damage, so don't clean it with alcohol or apply Rainex or similar to it while installed. Note that you can put fuel or alcohol or Rainex on it without any harm being done while it's flat. The cracking is a stress cracking, i.e. rapid cooling while stressed from being curved. You're not likely to curve the acrylic successfully unless it's very thin or unless you heat it (about 350F) and lay it over a mold the shape you want it to end up in. If you flex acrylic into shape there is a risk it may shatter at any time, particularly if something hits it. Give consideration to not using tinted sheeting, particularly for the windshield. Side windows are fine if they are tinted, and if you use the car tint material from USA you will get a good result - the common and cheaper Chinese stuff is the one that you see on cars with peeling and crazing. The problem with tinted windshields is if you ever get caught near end of daylight you can't see a thing. If you're wearing sunglasses you can take them off but you can't suddenly un-tint your windshield. 1 Link to comment Share on other sites More sharing options...
icebob Posted May 24, 2013 Share Posted May 24, 2013 I would agree with above. My own building I used the "Lexan" only for the windscreen because of it's better optical qualities and also can have minor scratches polished out(kit purchased from UK) better than the other brands. I used the cheaper brands for the side windows, the only issue I had was using a too thin a thickness and had the oil canning effect, when I went to 2mm the window would shake but not make any noise. As a side issue when I fitted one of those clear air vents into the side window the shaking stopped? Bob. Link to comment Share on other sites More sharing options...
fly_tornado Posted May 24, 2013 Share Posted May 24, 2013 you can clean polycarbonate with swirl remover. Link to comment Share on other sites More sharing options...
Blueadventures Posted June 9, 2013 Share Posted June 9, 2013 Good idea, I think I'll take a cordless and some hole saws out on the weekend Hi Met2 How did the holes work? Cheers Mike Link to comment Share on other sites More sharing options...
metalman Posted June 9, 2013 Author Share Posted June 9, 2013 Hi Met2 How did the holes work?Cheers Mike Mine are totally stuffed now, I'm going to get some acrylic and redo them, and put holes in the new ones, You got a sale on your fox yet? Plans for a new aircraft? Link to comment Share on other sites More sharing options...
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