Wayne, The Alons where all OK. As far as the poping noise mine do that too. So do the old ones. I think they get a little flex where the gear is. I think ALL the spar caps are rotten on the metal wing 415 Ercoupe. You do not really know how bad they are till you take them apart. If you do all that I think it is easier to just put in a whole new spar. People keep talking about putting on 54 year old spar caps on their planes, they should buy new spars. I think you can get them from Univair. You will get the money back on them when you sell the plane. If you keep your plane you will have a plane for many years with good spars. gene
[EMAIL PROTECTED] wrote: > Gene, > > I have a 1966 Alon and I am trying to find the source of a "popping" noise in > my wings. I have spent about 6 hours with four different people helping me > to try to find the source of this noise, but haven't been able to find it. > The inside of my wings look excellent with very minor surface corrosion on > the inside of the wing skins and ribs, and no corrosion on the spar or > capstrips. The spars and caps are zinc chromated. I even stripped a small > amount of paint off of one of them and it's bright shiny aluminum under the > paint. We have inspected in detail for cracked ribs, spars, capstrips, etc. > The noise that I am hearing occurs when I push the wing tip up hard. It will > pop once when you push it up, and then when you push it down hard it will pop > again. The noise is directional in that if it pops when you push it up, you > have to push it down in order to get it to pop again. The noise is very > difficult to locate because the sound seems to bounce around in the wings, > but I am convinced that it is coming from the area right around the main wing > spar attach fittings. I have checked the wing attach bolts, and the sound is > not coming from this joint. It sounds to me that the noise is coming from an > area just outboard of the wing attach bolts, at the inboard end of the top > capstrips, BUT there is NO visual indication that there is anything wrong > with them. All of the rivets are tight and are not "smoking". There are no > breaks in the paint around any of the rivet heads. The capstrips look > excellent and have no cracks in them. > > I read your post about the bad spar capstrips, and I have a few questions for > you. > > 1. From your post, am I correct in understanding that you had an Alon > Aircoupe that had rotted spar capstrips, but had no visual signs that they > were bad? > > 2. How is it that the inside of a spar capstrip can corrode, when the > outside looks perfect? Is this from moisture getting in there, or a factory > defect, or what? > > 3. Do you know of any way to determine if the capstrips are bad short of > disassembling the whole wing? Any type of testing? > > 4. You wrote: <<One plane the caps looked real good after we took > skin off and I didn't think they needed to be replace, but the man who > bought it > wanted to play it safe and put on new caps. When he took the old caps off > the spar > than you could see they were ROTTEN from the inside.>> Was this plane an > Alon? Can you put me in touch with this individual so that I can talk to him > about what he found? > > I really appreciate you reading all this and providing any info that you can. > I just hate to disassemble a pair of wings based on nothing more than a > noise. As I said, everything LOOKS perfect. > > Thanks, > > Wayne DelRossi > Alon N5618F > Simpsonville SC
<<attachment: winmail.dat>>
