| Author | Message | ||
     John Harlow |
Thought for sure that my tanks were sealed, but after 1 week I found fuel on the belly this AM. Since I only have fuel in the Rt outboard tank it has to be coming from there. Fuel stains are aft of the main spar in the area where the landing gear is, but none behind the the outboard tank. The area behind the inboard tank does not have access for viewing but stains are showing at the aileron push pull tube hole. So I think I must have a leak path under the spar from the outboard tank and migrating down the spar squish area and finally working out aft of the main spar somewhere closer to the fuselage. My hope is that someone can give me some advise on how to go about repairing. Is there a good sealer that can be poured in. The plane is 99% complete (final paint in progress) so the wings are not removable to permit turning with a slosh solution. I seem to remember an article in the EXPRESS LINK but have been unable to locate it. Thanks John | ||
| Tom R. Hutchison |
I have heard of other folks talk about sealing a leak by pulling a slight vacuam and aplying resin to the area or the hole where the leak shows up. This may not be possible in your case. Maybe you could drill a small hole where you think the leak channel is and feed in "hot" resin while pulling a vacuuam. Hopefully someone else will have a better suggestion (and they can spell vaccuam). Tom | ||
| Phil & Margie Hodge |
1) Vacuum. 2) Simply sealing the exit hole will only mask the problem, and probably only temporarily. The fuel will continue to leak out of the tank into the sturcture, and just collect there, or find another exit hole further downstream. Sorry, but if you want to fix it right, you need to deal with the source. Phil | ||
| John Harlow |
Phil, I have no intention of sealing the exit hole, I agree this is not the correct fix. What I'am searching for is what others have used for a sealer. My problem can't be an issolated one. Aircraft spruce has several sealers available and possibly one of them or the use of resin. If need be I will cut a hole in the top of the wing and put a mill fiber fillet in place.Right now I'am hopeing someone will share how they have addressed the same problem. Thanks for you responce John | ||
| jerico |
Dear John, Please call me about your leak problem and I will suggest a few things. I had a leaks in my wings at different points and fixed them. My pager number is 1-888-849-0747. I am in Napa, California so consider the time difference. I am up until 9:00 pm tonight. Jerry Sjostrand | ||
| John Harlow |
Thanks Jerry, Your suggestion has been implemented and I will put fuel back in tomorrow and I feel sure the problem has been fixed. The suggestion was to grind away the primer under the spar area down to bare glass and then wipe with a cloth saturated with Alcohol or Acetone. This will allow the surface to become transparent and shows up voids. I used mineral spirts since it doesn't evaporate as quickly. Lo and behold I found a void from the tank to the area aft of the spar which is where the leak must be. At first it was hard to start grinding because I was in final primer and ready for paint and didn't relish doing the wing body work over expecially lying on my back. Once the grinding was complete and the leak path identified, it was just a matter of drilling some 3/16 holes and injecting a mixture of mill fiber, Cabosil, and resin. I used a large syrenge that I purchased from a drug store for $2.69. I will report back with my results in a few days. | ||
| jerico |
Hi John, Great news about the leak problem. I hope that the factory or others will take advantage of the process I suggested for "looking into" the squish areas for proper bond and/or leaks. Any area where the fiberglass panel is bonded and does not have foam can be checked this way. For new builders, if you remove the gel coat/primer from the bonding areas before squishing, you can view the results as John did by simply wetting the surface with a liquid. I suggested this to Glasair years ago and they began leaving the spar area unprimed for this reason. The repair is to drill small holes in the void area and insert squish material with a syringe as John did. If anyone has further questions regarding this method, please contact me by pager or email. 1-888-849-0747 (include your area code) Your fellow builder, Jerry Sjostrand | ||
| Jay Villalva |
Great Idea! | ||
| Tom R. Hutchison |
Well, the new wings come from Bech-Techni (they also build the Glasair parts). The top skins are bonded to the main wing spar by them before Express receives them. They leave the spar bonding area without gelcoat so they can check the bond. However the bottom skins the builder bonds to the spar on close out, do not have this "clear strip". I wonder why not? It would be very easy for Bech-Techni to mask this area from gel coating. Great idea Jerry! | ||
| Mike AuClair |
I want to add my compliments Jerry. Not only for your innovative processes but for your unselfish willingness to share. Maybe we do have a better group than those other glass airplane people. No doubt about it! Also, thanks to Tom for this fabulous forum that he has developed. | ||
| John Harlow |
Fuel has been sitting in the tank all day and the previous wet area is dry. Leak is fixed!!! Thanks again Jerry | ||
| chris m |
From the factory... In the fall of 1999 we made the change to have that uncoated strip left off the wing skins for this exact reason. All new kits now have this uncoated clear strip. - Chris Michalak | ||
| LOUIE LACY |
Jerry My leak problem is from a different area. My tanks were sealed and I had no leaks until I opened the drain plugs in the right wing. After I put the plug back in I got a seep not a real leak from what appears to be around the plug. I have tried different methods to stop the leak teflon different sealers nothing to date works. My real concern is I have moved the plate the drain plug is in and now have a real problem. Will your idea of sanding off the gelcoat work with this problem or what plug sealer would you recommend. I have not nor intend to open any other drain plugs!! Lou llacy@netease.net | ||
| Jerry |
Hi Louie, Sorry about the delay in getting back to you about the leak at the drain plug. Bring me up to date on the situation by email or you you can call me here in Tucson, AZ at Frank Harris'. (520-577-1536) I am working with him on his CT empenage and will be here through Saturday this week. 9:am to 5:pm but gone from 12:00 to 2:00 pm. I had a similar problem on my Express with a drain plug. I removed the plug, drained the fuel, tipped the airplane so as to keep gas away from the hole. Then ground the area with a dremel tool, both the glass and the aluminum block. I made a stainless steel (or aluminum) disc large enough to cover the area, made matching holes for the plug and the small screw, used a resin, mixture with a bit of milled fiber mixed in, then bonded that to the metal block nd wing surface with the plug and the screw in place (grease on the threads). When cured, remove the plug and screw, clean up the area, reinstall the parts and check with fuel in the tank. You mentioned your block came loose. If it is in fact "loose", then lift in up into the tank with a piece of pipe screwed in to it so as to have a handle. Sand or grind what you can reach, clean and put resin mixture between the block and the inner skin so as to have a "squish" when installing the plate, plug and screw. Tighten them just enough to make them flush with the plate and wing surface, clean up the excess squish and allow to cure. I would put a heat source on the area to encourage the cure being careful not to over heat. I hope this helps with your problem. Let hear from you. Cheers. Jerry Sjostrand | ||
| Blake Richards |
I have s-90 with wheeler wings and lower fuselage. An EDI uper fuselage, and Express aircraft gear-flap-aileron-hardware. I have a few questions about the fuel system. I plan on ordering a new Continental IO 550-n with hartzel 3 blade prop I am just about to close up the three access holes in the bottom of the wing, to change over The original wheeler 4 tanks into one tank per side. It would be a great if anyone could comment before I close up the holes. So far I removed the outboard fuel pick up and plate, removed all internal fuel lines as well as the Rochester fuel sender. I then glassed over or plugged and pro-sealed over the holes that were left, -drain blocks- inboard fuel cap-outboard pickup plate hole, fuel sender hole. I then cut fuel and vent holes in the dividing rib. I drilled the holes for the sky sports capacitance fuel probe, and am about to install white plastic pvc fittings as bushings in the fuel tank ribs. This makes the fuel probe removable (as per express aircraft manual). Then I plan on adding a small support rib about 8" outboard of the fuel pickup rib to support the inboard end of the capacitance probe. I will also support the fuel return line in this rib. The return line is then routed 8" inboard to what used to be the outboard fuel pick up aeroquip fitting. Next I replaced the wheeler fuel drains with a Cessna drain located in a sump I created in the inboard access hole cutout, by removing some of the inner skin and foam and adding 4 layers of glass to create the lowest place in the fuel tank. This allows water to collect here and be drained. While I have three holes in my wing undersurface I plan on glassing the inboard and outboard ribs to the lower wing skin as well as the inside of the leading edges. I will also paint some resin along the spar cap edges to further reduce leaks. Then I Plan on bolting a 18 gauge wire to the fuel cap and routing it through a small hole drilled in the top of the outboard rib along the edge of the spar cap sealed with pro seal then run back inboard to be grounded. 1. Is it o.k. to put pvc fittings in fuel? 2. Is it o.k. to put the fuel return line only 8" away and in the same fuel bay as the fuel pickup? 3. Do you think the fuel cap ground is necessary? 4. Do you have any other suggestions before I close up the holes Thanks for any ideas and comments, Blake |