How to Make a Poor Man's Spar Alignment Tool

[OHM Ω http://aviation.derosaweb.net]

Hope you find this presentation useful for your winter project enjoyment.

http://aviation.derosaweb.net/presentations/#spartool

Regards, John OHM Ω

[s.bral...@gmail.com]

Or if you don't have the tools for a DIY tool see:
http://glidersource.com/cgi-bin/post.cgi?id=1306

[moshe....@gmail.com]

Thanks Ohm. Have you tried filing part of of the hardwood pin to actually make it "eccentric"? In my glider that part (built into the spar pin) makes a huge difference, as it pulls the two wing halves together as you twist it.

[markm...@gmail.com]

Steve Bralla manufactured the "Z5" eccentric tool for several years before losing access to the machine tools needed for fabricating them. He kindly offered the rights to me a couple of years ago. I have been building them since then, and although they are not on my website (yet), I am still making and stocking them.

info (at) mmfabrication (dot) com

[tow...@gmail.com]

On Monday, January 7, 2019 at 1:27:14 PM UTC-8, markm...@gmail.com wrote:
> Steve Bralla manufactured the "Z5" eccentric tool for several years before losing access to the machine tools needed for fabricating them. He kindly offered the rights to me a couple of years ago. I have been building them since then, and although they are not on my website (yet), I am still making and stocking them.
>
> info (at) mmfabrication (dot) com

I've got one of the Z5 eccentric tools, and its a great help. But it can only be inserted when the wings are within about ¼" from closure. It would be even better if more eccentricity was present, to allow the tool to be inserted with the wings further from closure. I think the strength of the plastic tool could be maintained by putting a steel rod down the center.

[markm...@gmail.com]

> I've got one of the Z5 eccentric tools, and its a great help. But it can only be inserted when the wings are within about ¼" from closure. It would be even better if more eccentricity was present, to allow the tool to be inserted with the wings further from closure. I think the strength of the plastic tool could be maintained by putting a steel rod down the center.

Depending on the major diameter of the pin, I try to make the smaller eccentric stub as small as I reasonably can without compromising strength. Generally, a pin of 32-36 mm has a stub of around 22 mm, for about 10-14 mm advantage. I have made some pins with a smaller diameter stub, and incorporated a stainless steel reinforcing pin through the center of the stub into the main body. Naturally, this option will cost more. I also have the capability to mill a 1/2 inch square socket in the end for a 1/2 inch drive ratchet in case the handle holes (at 45 degree spacing) aren't sufficient for handle clearance inside the fuselage.

[OHM Ω http://aviation.derosaweb.net]

I have updated my simple presentation to add a warning (and a paint scheme) about mistakenly leaving the wooden spar alignment tool in place after finishing rigging instead of replacing it with the proper steel pin. Many thanks to Lee Braith for pointing this flaw out to me.

http://aviation.derosaweb.net/presentations/#spartool

- John OHM Ω

[JS]

On Tuesday, January 8, 2019 at 7:07:57 AM UTC-8, tow...@gmail.com wrote:
>
> I think the strength of the plastic tool could be maintained by putting a steel rod down the center.

That would be the Cobra one, owned a few. May have one or two at home to sell. Think they're for ASW27/28/29 and Duo.
Jim

[herbk...@gmail.com]

John, when moving from a more humid climate to the dry air out West your dowel will fail miserably. If your tool works here in Chicago, you'll find it rattling around in the bushings when out at Nephi. The drying wood shrinks quite substantially. Do it right and make the tool out of steel or plastic.
Herb, J7

[Charlie M. (UH & 002 owner/pilot)]

Better range......make it out of metal. I have used "home brewed" aluminum to good success in the northeast. Plastic may work fairly well, yes, wood changes a lot depending mostly on humidity. Metal changes more with temp (the whole, "thermal expansion thingy" which aluminum changes more than steel).

[OHM Ω http://aviation.derosaweb.net]

You could be correct about the humidity changing the diameter of the dowel. However, a well seasoned and well sealed ash dowel may well not have that problem. Time till tell.

Again, this is a poor man's version of this tool. Easily finding the correct diameter metal or plastic/nylon rod, without machining capability, may be rather difficult.

Maybe I should have called this the "poor CHEAP and EASY man's spar alignment tool"!

My $0.02 (or ZWD 10,000,000,000).

- John OHM Ω

[Charlie M. (UH & 002 owner/pilot)]

Nice DIY sheet.

[herbk...@gmail.com]

My contrarian view again (sorry John): All Schleicher gliders I have owned and operated assemble extremely well without this "aid". If you have trouble with your glider, it's more likely the mistake is with you rather than the glider. Have someone help you who knows what they are doing. Also, go put the glider together more often, get practice. Watch the Ridge Boys Striedieck, Seymour, Good et. al. assemble their gliders in their grid position at contests every morning in no time at all to understand what I'm saying.
Herb, J7

[uncl...@ix.netcom.com]

I'm one of the Schleicher boys that have found that an alignment pint is very helpful on 27's, 28's and 29's and any that have the short rounded nose. Mine is aluminum and about .010 under diameter with a taper about 1-1/4 long and small diameter at end about .200 smaller than the spar hole. I makes small alignment errors a not issue.
UH

[chip.b...@gmail.com]

Gotta agree with UH. I've owned my ASW 24 for 27 years and probably assembled it 800 or more times. I have a plastic rod (HDPE?) a little smaller diameter than the main pins (how's that for detailed specs?). About a foot long. Not tapered, although it should be (add to my "to do" list for 2019, page 3).

Very useful to lever the wings together the last few mm (i.e., not the eccentric, "rotate to align the bores" type of tool). As an ex-Libelle 201 driver, I was predisposed towards the "over center" wrench approach anyway. And if I recall, the pins on my LS-3 had a longer taper, which helped do the same thing. Schleicher seems to take the attitude that "if you want to fly our gliders, you'll care enough to align everything perfectly." Doesn't always work for us Americans originally trained on Schweizer 1-26s with a toolbox full of drift pins and hammers. :)

True, all but a few percent of my rig/derig operations are solo. I probably wouldn't find the tool quite as useful if I used a helper. But it lives in the Schleicher main pin pouch so it's always available and frequently used.

Chip Bearden

[Charlie M. (UH & 002 owner/pilot)]

Herb, I know you, FWIW......

I have assembled many gliders over the decades......
At least once a season, clean fuselage pins and lube....same for spar pins and bushings.......
A "slightly smaller" alignment pin (usually concentric, no real need in 99.9% of times for cam type), helps for first main pin alignment.
Clean pins and sorta decent lube is about all that is needed.......

[Dan Marotta]

I'm with Herb (I know, alert the media) but I assembled my gliders for
over 30 years without the aid of a tool, except for the Mosquito which
came with a factory supplied tool.  What was I doing wrong?

--
Dan, 5J

[uncl...@ix.netcom.com]

The difference is that the Schleicher gliders in this group have no taper on the end of the main pins, only about a 3 mm radius. This is due to the fact that they have no extra length to allow for a taper. If the alignment on assembly is not almost perfect, the first pin will not go in. The alignment tool helps with this. It is obviously possible to assemble without it but it is much easier with it, especially on a new tight glider.
UH