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Panther 92

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ykachuro

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Re: Panther 92

PostSun Jan 28, 2018 11:35 pm

Back in the groove...
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ykachuro

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Re: Panther 92

PostFri Jan 12, 2018 10:40 am

A quick update. Received the rest of the kit before the holidays. It has been somewhat on a back burner because of family/friends visiting and because of my indecision about doing the short wings v. Long wings. The kit inadvertently came with the parts for the long wing, and I revisited this issue even though I thought I had decided on the short wings. After much heated but mostly friendly deliberation with myself, I’ve decided on the long wing.
And I’ve been prepping wing ribs in the meantime — will post some pics today/tomorrow. Will be setting up the wing jig per the BM.
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ykachuro

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Re: Panther 92

PostSun Oct 29, 2017 1:13 pm

Just to keep it in prospective, try asking Avdel about the use of their "cherry" pulled rivets for aircraft construction. I am sure your conversation will be just as short.
The amount and the layer thickness of epoxy used in the method I am describing is no more than the amount of primer you would use for priming the part. I can't see how it could possibly lower the structural integrity. You would still use the rivets as spec-ed.
Why do it? Why not?
I recently looked at pictures of an RV that experienced in flight tail and wing failure obviously due to exceeding the design loads. Other than spar failures (the airplane basically disintegrated in flight), you could see the failure of aluminum skins right along the rivet lines. The rivets stayed, but the skin failed at the rivet joint. So, on that RV the rivet/skin joint as a whole was a failure point. I doubt that strengthening the joint at the rivet line woul've made a difference in that case, but who knows.
Here is the accident report: https://app.ntsb.gov/pdfgenerator/Repor ... l&IType=FA
Here is the link to the appendices, including pictures: https://dms.ntsb.gov/pubdms/search/hitl ... 9E3BE61D8C
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Lowrider

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Re: Panther 92

PostSun Oct 29, 2017 9:39 am

I would advocate use of composite materials in place of conventional construction methods...except I don't have the experience or expertise to know right from wrong. I talked to a lot of companies who produce these products and as soon as I mention private homebuilt airplane their response is uniformly..."thanks for your interest in our product, have a nice day". Doing the crossover from the defense industry to private use in home built planes is coming but no one that I talked to was willing to allow their products to be used for that purpose...that's why I'm bending alum and bucking rivets. The technology is out there but the lawyers have it tied up for now. I worked for General Dynamic for awhile after I retired and I remember a demo of a carbon fiber wrapped antenna that was attached to the F-16 with a "tube of stuff"...I wonder what it was.
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ykachuro

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Re: Panther 92

PostSat Oct 28, 2017 11:53 pm

5200 is amazing stuff. It would be quite messy and would add some weight though. The way I ended up experimenting with west epoxy is that I would dip very so slightly some maroon scotch brite in neat epoxy and would work it into aluminum surface until the thin film of epoxy turns slightly grey with aluminum powder (both surfaces to be riveted). I estimate it would take no more than an oz of epoxy to do all spar stiffeners (horizontal and vertical) on the tail. West testings show adhesion strength of 105/206 epoxy to aluminum of about 2,000 psi (2,500 psi with their g-flex epoxy). For comparison, the tensile strength of a 1/8 BSP rivet is 325 lbs. here is the link to West's testing http://epoxyworks.com/index.php/aluminum-adhesion/

Again, I am in no way advocating using epoxy or any other adhesive in addition to or, g-d forbid, instead of rivets!
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Lowrider

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Re: Panther 92

PostSat Oct 28, 2017 9:32 pm

Just for what it's worth I did a lot of experimenting with different bonding materials and the one that did not come apart during tests was 3M 5200 marine sealer/adhesive. 2024 alum up to 0.032 tore and the 5200 did not fail. I got the idea from an IA in Alaska...they use it routinely up there with great success on float bottoms. BTW, I had to use the bucket on my front end loader to tear the alum with a straight pull. The other one that was good was a 3M two sided adhesive tape used in construction of Semi trailers...can't find the stock number but it's used in place of rivets.

Take it for what you paid for it.
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ykachuro

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Re: Panther 92

PostSat Oct 28, 2017 5:29 pm

Just a quick update while I wait for the rest of the kit. I tried vinyl wrap on the tail fiberglass tips with consistently unsatisfactory results. I am sure it works fine with flat forms or with pieces with simple large radiuses. I couldn't make it wirk well for the tail tips. So, I'll be painting them, but later when I have the wing tips fitted.
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ykachuro

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Re: Panther 92

PostSun Sep 24, 2017 8:11 pm

While I have some downtime, started researching the electrical system. Ran into Bob Nuckolls website http://www.aeroelectric.com and finding his publications to be extremely helpfull. Downloaded and started reading his book.
I was wondering if there is somewhere as entertaining and as comprehensive readings on the aircraft fuel systems...
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ykachuro

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Re: Panther 92

PostWed Sep 20, 2017 10:41 am

Here is another thought.and I am really getting ahead of myself. As I said, I currently dont plan to paint, except for the fiberglass parts. I might do vinil wrap of the fiberglass parts instead. I think it might require less prep and would be overall quicker. Plus, it would be easier to take it off and try again if i mess it up or dont like it.
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ykachuro

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Re: Panther 92

PostWed Sep 20, 2017 10:32 am

Dan, thank you! This is very helpful. I wont do the epoxy thing afterall. I suspect I'll have some opportunity to play with it when i fit and finish the feather tips, the cowling and the canopy.

It's also great to hear what you say about the Lycoming. I was actually thinking about whether I'd have to mess around with the battery location for the CG sake. I am glad I wouldnt have to -- it would've added complexity and weight (that thick copper power cable is heavy).
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