Hangar Flying => Hangar Flying => Topic started by: Micah on March 21, 2012, 10:03:27 PM
Title: Hello and VE wing attach fittings
Post by: Micah on March 21, 2012, 10:03:27 PM
Hi all I'm new to forum here and wanted to say hello.
I'm in the process of reassembling a Verieze (S/N 43) and see that my wing attach fittings are different than the plans. Basically instead of the four tapered cups with two bolts passing through, mine has four shorter bolts that screw into nut plates. The aircraft has about 120hrs TT. My question is, should I try to retrofit to the plan specs or would any issues with this setup be apparent by now, ie. it would have failed by now?
My first instinct is to correct it to plans specs, but it's got 120hrs.... Also, anyone know where I could get my hands on a set of the tapered cups?
Micah DeLeeuw Zeeland, MI
PS I can post some photos if that would help.
Title: Re: Hello and VE wing attach fittings
Post by: Joe Person on March 22, 2012, 06:20:44 PM
Post some pics please - this sounds quite non-standard. If non-standard, and just because it has not failed, does not mean it can't or won't.
Title: Re: Hello and VE wing attach fittings
Post by: Micah on March 24, 2012, 08:13:00 PM
Ok, I'll try to post them tomorrow.
Title: Re: Hello and VE wing attach fittings
Post by: Bruce Hughes on March 25, 2012, 01:35:30 PM
Hi Micah
Where do you live? You need help from a Varieze expert (which Joe Person is). I know of 6 people that are scattered over the US that I would trust. You may be close to one of those. Tell us where you live!!!.
Bruce Hughes :)
Title: Re: Hello and VE wing attach fittings
Post by: Micah on March 25, 2012, 07:55:09 PM
Well here are the photos. I live in Zeeland Michigan, which is about half an hour west of Grand Rapids. To be honest I think I would feel better about converting back to the plans design. I just can't seem to find a set of the tapered plugs for sale. I have a CD set(Terf I think) with the plans for several rutan designs on it but it does not have the specs for the tapered plugs, I have talked to a local machine shop about making them for me, but I need to find the exact dimensions. Any help here would be appreciated as well.
PS in the pics, I haven't tightened the bolts all the way down.
Micah
Title: Re: Hello and VE wing attach fittings
Post by: Joe Person on March 26, 2012, 12:30:20 AM
Micah,
I would not trust this configuration structurally for any length of time. While the .50 inch diameter dimension of the fastener may be adequate from a pure load-bearing standpoint (I'd have to crunch the numbers per Lug Design requirements), the overall configuration is not ideal.
1. You have to rely on turning the bolt in the bore of the stack-up of wing fitting components to secure the bolt - this will wear the bores, over time.
2. Given 1, above, and with the specific structural configuration of the fiberglass sparcaps and associated shear/bearing pads that are buried beneath the .125 plates (wing and centersection spar), it is too easy to impart non-symmetrical loading of the fittings (from flight loads from the wings), such that you begin to impart bending moments in the sparcaps immediately adjacent to the .125 aluminum fitting components. The fit of the fastener in the bore that runs through the entire stack-up of the assembled fittings MUST have a very good fit all the way through - this is the main reason for the per-plans taper pin configuration. When you begin non-symmetrical loading of the fittings (e.g. if the "inside" .125 plate takes the majority of the load), you can start to fail sparcaps in localized bending at g levels considerably lower than what these structural joints are designed for.
Taper pins are roughly 1 inch in diameter at the big end, and generally protrude above the outermost .125 plates between 1/32 inch and 3/32 inch. They are around .75 inch tall, and the taper, per-plans, is 10 degrees included angle. They are counterbored from the large end, to allow installation of an AN960-416 washer and a .250 inch Grade 8 Bolt. Lower taper pins are tapped 14/28. Upper pins have a 1/4 inch hole. The thickness of the bottom end of the pins is roughly 2/10 inch or so. (I'll snag a spare pin and take some more precise measurements, some time this week.). Material is 4130 steel, heat treated to 125 KSI & Cad plated.
Title: Re: Hello and VE wing attach fittings
Post by: Bruce Hughes on March 26, 2012, 01:45:57 AM
You can see from Joe Person's post that you have a job ahead. He has built two great Variezes and he is a metal expert for Boeing. What he says is 100%. I know 3 people that might be able to help you. Call all 3. (1) Ken Miller in New York (see www.ez.org for a number). (2) Valerie Harris and her husband (I'll get her address) (3) Burrall Sanders (Meadowlake airport in Falcon, CO) (I'll get his address). I think you will have to trailer the Varieze to one of them; the one that has time to work on it. Maybe there is someone in Michigan that Ken or Valerie or Burrall knows.
Bruce Hughes :)
Title: Re: Hello and VE wing attach fittings
Post by: Micah on March 27, 2012, 12:01:02 AM
Thanks a lot for both replies. Especially for the dimensions of the taper pins. I will definitely be converting it back to the original specs. Micah
Title: Re: Hello and VE wing attach fittings
Post by: Super-EZE on April 06, 2012, 11:32:01 PM
I can lend you a taper pin for a few months to have it reproduced.
Title: Re: Hello and VE wing attach fittings
Post by: Bruce Hughes on April 07, 2012, 03:20:00 PM
Ask Joe Person which metal to use!
Bruce Hughes :)
Title: Re: Hello and VE wing attach fittings
Post by: Micah on April 09, 2012, 02:48:47 PM