After speaking to a friend of mine a couple of days ago I was informed that he had the steel pins break on the struts on his new Flash during landing. Since this is the second time I have heard about this I did some research and found that McMaster Carr sells steel dowel pins.

I ordered and just received a box of ten dowel pins for mine that are made from 18-8 stainless steel. I tested one pin with a hammer in a vise to see how they would handle an impact and instead of breaking they simply bend. As a matter of fact you can bend the pin back and forth repeatedly w/o it breaking. I am not sure this is the perfect answer but they do bend instead of snapping off and breaking like the stock pins I have heard about.

They come in a box of ten and are 6mm x 50mm in length which will work for both the mains and the nose struts. They fit perfectly in the existing retract holes and the price is only about $8.00 for a box of ten.
They also sell some hardened stainless steel pins but they only come in boxes of 25 and the cost is $40.00 so I thought I would try the 18-8 stainless pins first and if they are not strong enough I will order some of the hardened pins. The hardened pins are Rockwell 60 hardness which (according to the Rockwell charts I reviewed) appeared to be a medium hardness.

Anyone interested can use part number 91585A177 to order the 18-8 dowel pins directly from McMaster Carr. Even if the 18-8 pins are not strong enough I feel better knowing that they will simply bend and not break in half resulting in damage to the plane. I will be doing the maiden this weekend so I will let everyone know how they work out for me. Gary

Thanks for the info - I'll have to get some for my Lightning.
Good Luck on the Flash maiden.
...Scott

I had one pin break on my Lightning as they are designed to, the idea being that the potentially damaging shock loads are not passed on to the airframe. A pin is much easier to replace than airframe repairs.

Rob.

Guys

Yes, I broke one and replaced it with a softer pin..this kept moving just enough to catch the gear...so I went back to the hard pins and have not had a problem again.
The pin that snapped was on a "slide" after one brake grabbed. It broke where the flat had a sharp corner.
The new ones I left a radius and its still fine after 20 flights

Dave

Will the pin Gary mentioned fit in the Lightning?

The Lightning pins are M8 x 60

91585A209 18-8 stainless, pack of 5 for $8.22

91595A585 hardened steel, pack of 10 for $8.06

http://www.mcmaster.com

Thanks ScOtt. Did you get the 18-8 stainless or the hardened one?
David

I tried the 18-8 pins and do not recommend them...It is better to use a hardened pin and if they do break they are much easier to remove. The 18-8 pins will bend fairly easy. Buy the more expensive hardened pins..Gary

Gary,
The hardened pins are cheaper than the 18-8
David

I got the hardened pins. What's kinda ironic is the bag says "Made in Germany" and the pins have the excact same chamfered ends as the ones from Behotec. Can't get any better than that.

Does anyone know if this pin problem has been corrected in the later batches of kits?

Regards

Jim

Its not a problem, its designed to sheer off instead of tearing up the wing. I was told that be very careful when grinding the flat spots on the pins for the set screws, use a fine drum and make a radius dish shape and not a square shape. If you look in the manual it shows a picture of what I decribed. As Dave mentioned about he redid his gear and is going strong for over 20 flights.

I was also informed if sofe pins are used they will bend fine, but might jam up the in the gear wells and you will have a gear up.

This is what I have gathered.

Thanks. All I need now is the airframe to arrive. Latest report is container due to arrive in Germany 12th December.

Regards

Jim

Would the newer trailing link type of gear work better on the FLASH for grass field operations?