Hi Ian, Min amount of material required around the hole varies with type of material and loading it experiences (aluminium and cast iron need more than mild steel & High carbon steels need even less, but you are right and in the Hoffmann thrust ring less than hole dia x 1 is not good design.
Nylock nuts in reverse for the inner nuts on the Hoffmann pitch change rods would be an acceptable fix, but on pushrod ends is not the best answer as it will stay locked to the rod thread but the nut face can still loosen against the rod. Best method is a double tab washer which locks one tab against a flat on the pushrod ( not on all rods, you may have to file one) and another tab against the nut. Some rod ends have a groove in the thread for a locktab with an internal tang, again one tab against the flat on the rod & another against the nut. Re; supplies of FC332 see my earlier e-mail. I am happy to purchase & post to any owner who has trouble obtaining FC332-4, -6 & -8 hose, also correct size Oetiker clamps. Type 154 (single ear stainless steel with liner) for hose attachment, and type 101 (2 ear zinc coated steel) for securing firesleeving. regards JGV ----- Original Message ----- From: Ian Mc Phee To: DOG LIST Sent: Friday, May 25, 2012 8:55 PM Subject: [DOG mailing list] nuts on rear of front plate in 3 position hoffmann/MT prop A friend with a Ximango has had the inside nuts (non locking) coming loose and been talking to Eric Weston he has replaced them with nylon lock nuts put on in reverse so now they really lock on the prop front plate. I am not impressed how the hole size is increased in plate from 6mm to 8mm (for the 8mm rods) BUT the plate is made no longer. I seem to remember somewhere in engineering there should be beef of 1.5 times the diameter of the hole on the outside of the hole ie 12mm. No way it is about 6 or 7 mm from memory. Don't these makers have any engineers working for them any more or look at what they post on EASA site when they decide to issue a SB? As some know motor PIKs have had the locking nuts coming loose on ball rod ends in the wing which can cause ball rod ends to crack and break (It happened to our PIK E 15 yrs ago) Anyhow a friend with a PIK replaced all the ordinary 6mm nuts with nylon locking nuts and screwed them on in reverse so now they positively lock the ball rod end to push rod. Both seem like a good idea to me to solve a problem which the makers never thought of. I am not at all impressed with the service provided by the so called Diamond agent in Aus Hawker Pacific. Took guess 6 emails to Austria and only on May 1 (Europe Public Holiday) did I get several "out of office" emails so Austria were getting them. Eventually Australia replied but no mention of the various spares I asked prices of. Not impressed compared to 4 years ago I got a phone call from Austria 30 seconds after I pressed the send button on an email. That was the then Canadian speaking Parts Manager. in Austria. S L A C K if you ask me Finally does anybody know where to buy Aeroquip AC 332-4 (or -6) blue fuel hose as my source in Brisbane no longer stock same. Has anybody used the aviation Aeroquip AE-466-4 etc hose The main advantage of this hose is it has red cover of fireproofing on the hose at manufacture but is expensive I guess.. Ian McPhee (PS I suppose I am just a grump)
