Brodhead Pietenpol Association

Original Posted By: "Gordon Bowen"
A question about hardware,Question: What length bolt to use.Hypothetical situation, say we have a -inch thick structural member and we need to bolt a 1/8th-inch thick fitting to one side. This would make the through hole length 1 1/8th-inches long. I am guessing the bolt should be based on the grip length, so in this case I would choose a bolt with a grip length of 1 1/8th-inch. According to the charts there are no bolts with a grip length of 1 1/8-inch. So I would choose a dash 16 (AN4-16 for instance) which has a length of 1 5/16. I would choose this so the threaded portion of the bolt is longer then the through hole length. I would take up the extra length with a washer. This works fine until you try to use a safety wire nut on a drilled bolt, the nut seems to be below the hole in the shank, and thus the safety wire will not hold the nut.Follow on question, is it ok to have the threads in the fitting hole? I would assume if you had threads in the wood part of the hole it would be ok.Also, is everyone using the large diameter wood washers under the side of the bolt against wood (head or nut)?Chris TracySacramento, Ca________________________________________________________________________________

Original Posted By: "Catdesigns"
Tracy,The best place for a short course on min. bolt length/type etc. is Sacramento Sky Ranch's Tech Book and FAA's Advisory Circulars AC 43.13-1B and AC 43.13-2A "Acceptable Methods, Techniques and Practices-----Aircraft Inspection and Repair",, both are available via Jeppesen, AirSpruce or direct from SkyRanch. These two tech books should be on every homebuilders bookshelf for reference. Every AP I've known has a dog-eared copy of the FAA AC's, they use it for reference as a bible. I like SkyRanch's tech explanations and pictures of failed bolts and such to help understand the science of materials and materials selection for homebuilts. You listen to a bunch of homebuilders, you'll get as many answers to your technical questions as you will the number of people you ask. I've known some guys, who's only source of technical information was the front of the ASpruce catalog and talking on the phone with a ASpruce telephone rep, who's probably only seen a homebuilt in pictures. You should go right to the source documents for your answers.Gordon----- Original Message -----

Original Posted By: "Gordon Bowen"
Gordon,Dang! I was just at Skyranch yesterday buying the bolts and it never occurred to me to ask if they knew the answer to this. I thought they only did engine books. Guess I will wander over at lunch on Tuesday. I already have 43.13-1B and 2A. I will look again in there to see if its in there. All I remember is the 3 treads showing above the nut.Chris TracySacramento, Ca----- Original Message -----

Original Posted By: owner-pietenpol-list-server(at)matronics.com
I believe the best advice is than posted by Gordon Bowen, but remember theFAA has thread standards for every bolt and they have to have at least threethreds showing behind each nut. I think the bolts with shafts and threads on the ends are better for woodthan a completely threaded bolt. Check the FAA Advisory Circular ASAAS43.13B everything is there.Rob-----Original Message-----

Original Posted By: shad bell
Shad,A couple of questions:1. Where did the crank break?2. What is the "clock" position of the prop in relation to the crank throws? Was the prop parallel or perpindicular to the crank throws? Some people on the corvair list believe this is critical.Greg Cardinal ----- Original Message -----

Original Posted By: shad bell

Original Posted By: Clif Dawson
I only know enough about these engines to be dangerous. For example, looking at the earlier engines from 65-85 hp (basically all 176 cubic inches and listed as Franklin 4AC 176 B2 through F3 models), they seem to be at least 20 lbs. heavier than their Continental engine counterparts with the same magnetos and carbs, but in a Piet that isn't really a handicap.Not sure how the 90 hp version shapes up against the Continental C90 (Franklin 4AC 199 B2-H3 series, 199 cu. in.), but again- even if it's a bit heavier that isn't a drawback necessarily. Parts availability seems to be the big issue with these engines.Note the 65 HP Franklin that was used on Ernie Moreno's Piet, at http://www.flysquirrel.net/piets/piets.html and you'll see that the engine mount is quite long on this airplane. The 90HP may make a better installation with a shorter nose.Oscar ZunigaSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________Date: Sat, 02 Sep 2006 22:37:52 -0700