Legal Eagle Question

Discussion in 'Tube and Fabric' started by Victor Bravo, Oct 12, 2019 at 3:18 AM.

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  1. Oct 12, 2019 at 3:18 AM #1

    Victor Bravo

    Victor Bravo

    Victor Bravo

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    I'm hoping to get some advice and info from THIS forrum, because I know you guys reasonably well from hanging out here. I have NOT yet joined any other forums, Eagler's Nest, etc. I know about those forums but I want to have this first part of the discussion here.

    I just ran across a completed Legal Eagle for sale at an attractive price. I believe that it is NOT the XL version. The airplane has an engine on it that I know nothing about, a Kawasaki ultralight engine. The wood structure was built with Weldwood yellow glue, not West epoxy, not Resorcinol, not T-88.

    I have not seen, touched, bought, or otherwise committed to it yet. (I'm looking at this as a potential airframe for the O-100 engine; I'm honored that I will likely be a "beta tester" and "fleet data acquisition mule" for the program.)

    My first question is what is the realistic range of acceptable empty weight for an original Legal Eagle? I know they can be built to 250 pounds, but this one has brakes, and this one would eventually have the O-100 on it (weight 105 pounds). I have no idea if this one was built as light as some of them. So the big question is NOT whether the LE can be built as an ultralight, but how much more than 250 pounds do they usually get, with a 4 stroke engine on them?

    Second question is... how much over 250 pounds can it get from a structural safety standpoint? I'm sure it would get off the ground at 700 pounds takeoff weight, but you wouldn't have a 4G or 6G airplane. No, I'm not going to do aerobatics in this one but we do get gusty weather here in the mountains around LA.

    (also, even though I stopped eatling like a pig recently, and have lost some weight, for some mysterious reason I'm still not getting any calls from swimwear modeling agencies. The mattress has about a 220 pound crater in it, and the dog only weighs 15 of that)

    Also, anyone here have personal experience using Weldwood as a primary structural adhesive for wing spars? (Yes I put in a call to Pete already, but I want everyone else's opinion too)
     
  2. Oct 12, 2019 at 4:34 AM #2

    FritzW

    FritzW

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    If you google around a little you'll find a stress analysis report TEAM had done on the original MiniMax (I might still have a copy). Since the LE wing is pretty much a clone of the MiniMax wing you could start there. Take that gross weight X 4.4G then divide it by your actual gross weight to get the actual G you can put on the airplane.

    (double check everything, I'm only kinda sure the MiniMax wing was designed for 4.4G at it's GW)

    Check the spar webs to make sure they didn't cut lightening holes in the strut attach areas (lots of pictures and rumors floating around that a lot of LE's did).

    Check the front two cabanes. Our local LE ("factory" welded fuselage) had a two stroke and both of the front cabanes broke about 4" down from the front spar attach (airplane landed safely). Because of the weird way they broke we guessed it might of been a combination of bad welding (heat affected zone?) and 2 stroke vibration.

    ...the other elevenbilzillion LE's with 2 strokes apparently never had a problem but it's worth a close look just in case.
     
  3. Oct 12, 2019 at 11:57 AM #3

    ArcticDave

    ArcticDave

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    The original Legal Eagle is rated @ 500lb gross. The XL is 575lbs gross. I wouldn't go much over either of those limits without beefier wing spars at least. More than likely some fuselage reinforcing as well.

    How much does that O-100 weigh?(Nevermind...looked on Pete's website- 105lbs, no starter, no exhaust, no oil, no propeller). For comparison, my 1138cc 1/2 veedub weighs 94lbs complete and ready to run. The original Eagle has a shorter tail boom than the XL version, and would require even more tail weight to be added to balance out the heavier engine.

    FWIW, I expect my modified XL project will come in around 300lbs when finished. My 200lbs and an additional 30lbs for fuel will put me about 530-540lbs flying weight. What you're talking about doing, could add a similar amount of weight and push you well over the 500lb gross of the original Eagle.

    As far as the glue goes, I have no experience with it whatsoever, but most modern glues are stronger than the wood being glued...including urea formaldehyde adhesives like weldwood. I have read a report somewhere about UF glue crystallizing after long exposure to heat and moisture, but I can't remember where I saw that, or if it is even true.
     
  4. Oct 12, 2019 at 12:17 PM #4

    litespeed

    litespeed

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    I too have heard of the crystalisation issue here in Australia- we generally do not approve of the glue for Aircraft use in Oz for this reason.

    Unless it was going to rebuild the wing etc, I would stay clear. Also a XL version would suit your engine better.

    You could just bite the bullet and build from scratch. Then you have a aircraft you can trust and built to suit your needs.
     
  5. Oct 12, 2019 at 1:49 PM #5

    Dana

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    I would walk away from this one based on the glue used. Yellow glue is my go-to for cabinet making but there's a reason people don't use it for airplanes.
     
    mcrae0104 and Pops like this.
  6. Oct 12, 2019 at 1:54 PM #6

    Rockiedog2

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    VB
    Leonard came out early on against any 2 strokes for the cabane cracking already mentioned. You didn't mention if the motor on this one is a 2 stroke but if it is and it has even very little flying time I would have to cut out the cabanes and replace those. I was involved in the very early testing experimenting and development and there were very few 2 strokes at that time. I got no idea about that now.
    The best way to balance a heavy motor is to build the tail outa chromoly which also solves the problem of increased prop blast from more power. The gear also will likely need beefing up as well as spar strap fittings etc. There's a LEU in East Texas with a 4 cylinder with 600+ hours on it last I heard. Dunno what all they did to beef it up other than steel tail. If you do the power/weight on a heavier/higher HP motor vs a 37-42 hp half Vdub the bigger motor doesn't make a whole lotta sense. And the wing loading for a given payload. Even tho I like what I know about the 0-100 the plane is designed for a half VW and that's by far the best motor for it; all things considered.
    The standard glue used to be Weldwood Plastic Resin or Rescorinol til ohhh...mid 70's or so when the heat aging concern came up and the Feds frowned on it. T88 came along about that time and most eventually went to it. I used a lotta plastic resin and none of it was yellow. Light tan to brown, depending how it was mixed. I wouldn't buy a Legal Eagle with spars other than epoxy glue simply cause they're built up spars; not solid spars with glued on reinforcing plates. Especially some unknown glue.
    What Fritz said on the spars. I didn't put the holes inside the strut attach even tho they were in the plans at that time.

    Lotta inexperienced builders built Legal Eagles. I'd go in negative til I spent a lotta time looking it over. I've looked at several for buyers and thumbs down on every one. And I don't like the sound of this one.
     
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  7. Oct 12, 2019 at 2:50 PM #7

    mullacharjak

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    If we assume that it has been built with DAP yellow glue implying that it is some sort of non water proof PVA glue then it is easy.Just melt the glue with water and reglue the joint with the proper DAP resin glue or T88 if you like.
    Just weld the broken joints in steel.The 2 stroke 4 stroke story is hard to believe.The airbikes flying with 2 strokes all along I think and this area is also very easy to inspect.
     
  8. Oct 12, 2019 at 2:53 PM #8

    Pops

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    I built a KR-2 and used Weldwood Plastic Resin before T-88 was out on the market in the mid 1970's. Now, I wouldn't use anything except T-88. I used the yellow glues on model airplanes but nothing else. Walk away and look somewhere else or build one yourself.
     
    delta and Rockiedog2 like this.
  9. Oct 12, 2019 at 3:09 PM #9

    Rockiedog2

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    Some of us don't assume anything.
    Easier to build a new wing rather than disassemble it and reglue like you're suggesting.
    The broken cabanes are from field history but don't believe it if you like.
    This isn't an airbike.
     
  10. Oct 12, 2019 at 4:08 PM #10

    Victor Bravo

    Victor Bravo

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    All right... that is exactly the type of information and opinions I was looking for. I've been the one to make these sorts of comments on other types of aircraft that I was personally familiar with, and I'm grateful that others were willing to give me "the straight scoop" whether it's pretty or not. Thank you all.
     
  11. Oct 12, 2019 at 11:55 PM #11

    ToddK

    ToddK

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    A lot of legal eagle guys (including Leonard) use Titebond for the wing ribs. The spars, compression, and diagonals really should be T-88.
     
  12. Oct 13, 2019 at 2:41 AM #12

    TFF

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    I wish I made a 220 divot without the dog. Actually a 220 divot would be great.

    How long has it been flown? Climate it is from. Storage. What condition is the smoker in? Last time run?

    I have built a lot of model planes with Tightbond 1. I like it better than 2 or 3 for that. It will come apart if it stays wet. Yellow carpenter glue, Spar would be a no for sure. Ribs I would probably be a wait and see. Ailerons,ugh. Once one goes they all would have to go. I doubt it was varnished in epoxy just because of yellow glue do there is no great first defense barrier. Curious on wood quality too. I would have to look at that.

    As for design, it’s pretty darn close to a much beefier airplane. I helped build a XL. I don’t think there is too much difference. Mostly just height. Fuselage is plenty strong. Good welds, it will last forever. Tail is aluminum tube. I don’t remember if it has one set of wires or two. If you put a 0-100 on it you want two sets or forward braces like a Pitts. I would be worried going too fast without it. Wing, plenty strong. If I was not going UL I would add a second ply spar web and completely box it in if it was in building phase. If f I remember the wing rib template has regular,XL, and maybe the Double Eagle all on the same drawing. Not much difference.
     

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