Tapered pins (again)

Helped the new owner beat his 27 together, last Sunday.............he looked shocked when I suggested he "taper" at least one pin. Nothing too severe, just 15 degrees and only on the part that extends out the back side of both spars. Found a 40mm pin in the barn from K-21 and it has 5 degree taper that starts an inch from the end, that sharpens to 15 degrees about 1/2" from the end. Looks professional, did Schleicher ever offer a tapered pin? Anything would be better than their blunt pin that will only start when everything is EXACTLY perfect!
JJ

On Tuesday, April 24, 2018 at 7:10:49 AM UTC-7, wrote:
Helped the new owner beat his 27 together, last Sunday.............he looked shocked when I suggested he "taper" at least one pin. Nothing too severe, just 15 degrees and only on the part that extends out the back side of both spars. Found a 40mm pin in the barn from K-21 and it has 5 degree taper that starts an inch from the end, that sharpens to 15 degrees about 1/2" from the end. Looks professional, did Schleicher ever offer a tapered pin? Anything would be better than their blunt pin that will only start when everything is EXACTLY perfect!
JJ

I checked how much extra pin length protrudes out the back of the spars on the 27. Unfortunately only the radius of the pin sticks out! On the other hand, the previous owner acquired an aluminum pin with lots of taper, a nylon pin with lots of taper, and a Delrin eccentric pin. Obviously this was an issue for him.

At least I will have something to try next time :-) Thanks for your help yesterday.

Matt

On Tuesday, April 24, 2018 at 3:10:49 PM UTC+1, wrote:
Helped the new owner beat his 27 together, last Sunday.............he looked shocked when I suggested he "taper" at least one pin. Nothing too severe, just 15 degrees and only on the part that extends out the back side of both spars. Found a 40mm pin in the barn from K-21 and it has 5 degree taper that starts an inch from the end, that sharpens to 15 degrees about 1/2" from the end. Looks professional, did Schleicher ever offer a tapered pin? Anything would be better than their blunt pin that will only start when everything is EXACTLY perfect!
JJ

Does the end of the pin definitely stick out beyond the spars? I wanted to do that to JS1 pins but apparently the pins were only long enough to fill the spar stub holes.

I was thinking about having my Pegasus pins tapered. I'll have to check how much is protruding from the spar. Who has done this and is it something any good machinist can do? Does the taper JJ mentions seem about right?

On Tuesday, April 24, 2018 at 11:13:41 AM UTC-4, wrote:
I was thinking about having my Pegasus pins tapered. I'll have to check how much is protruding from the spar. Who has done this and is it something any good machinist can do? Does the taper JJ mentions seem about right?

I own a Pegasus - and my pins are tapered - about 1/2 inch on the end - I believe that is the way it came. I do not have an issue assembling quikly.

Only once, I did have residue on the ring that looks like a big washer around the root pins - cleaned that and no more problems. Anything on that creates problems.

WH

If the water ballast dump valve is open or the airbrakes locked, assembly can be difficult.
If the flaps are in L position it will go together but the stick won't move side to side and the flap handle won't move.
MM Fabrication sells an assembly tool (designed and originally sold by Steve Bralla) that works very well. A more simple approach than tapering the pins. It wasn't on his website last I looked, so call or email Mark.
Jim

On Tuesday, April 24, 2018 at 9:03:55 AM UTC-7, JS wrote:
If the water ballast dump valve is open or the airbrakes locked, assembly can be difficult.
If the flaps are in L position it will go together but the stick won't move side to side and the flap handle won't move.
MM Fabrication sells an assembly tool (designed and originally sold by Steve Bralla) that works very well. A more simple approach than tapering the pins. It wasn't on his website last I looked, so call or email Mark.
Jim

Previous post was ASW27.
Jim

FYI- I am now producing tapered and eccentric wing assembly pins made from Acetal plastic (Delrin). They aren't on my website yet, but I generally have a few of various sizes in stock. Contact information (cell phone number and email) are on the website mmfabrication dot com.

I made the HP-24 pins taper a bit, and it doesn't take much to make a big difference. My pins taper about 15 degrees for about 1/2", and if that doesn't do it the wings are way out of position. In my ship there just isn't much room between the ends of the pins and the autoconnect hardware, since I've crowded that stuff forward in order to reserve a bunch of mid-fuselage volume to allow for BRS.

But I do make eccentric tapered pins out of Delrin where the axis of the tapered portion is inclined from the axis of the cylindrical part. These work great to draw the wings together the last little bit on sticky ships. I can make these in pretty much any diameter.

--Bob K.

Is the original pin hollow?
Is there room aft of the aft spar hole for a delrin tapered "extention"?
Or aluminum or nylon?
Just brainstorming.
Good luck
Scott