facthunter

Its been happening. They are too long and the steel doesn't expand as much as the Alloy. It's not an uncommon problem in such designs. . Be interest to have my question answered. Nev

What about your SAFETY in the Meantime? The days of people getting electrocuted should be over. Nev

Get those earth return circuit Breakers installed or you are NOT legal. They will POP instantly when some thing is wrong and a proper electricians screwdriver will indicate which wire is active. Nev

There seems to be a Major change there. Is that shortening the studs that have been Breaking in the Genuine Motors? Nev.

Thanks. Often cranks have sections that are much weaker than the general section and that concentrates stress in those areas. Poor design. Usually where a throw goes to a crank pin section. Billet is not really like a bit of grained timber as some imagine if it's rolled properly. The ends of each rolled length should be discarded if there's any chance of a Scarf being there.. Nev

I've seen Legless people coming out of a PUB, who were Blind drunk.. Nev

Why would a billet Crank weigh More than a forged one? I can't see why it would have to. (refering back a little way). Nev

That worked when I voted today. Nev

it's Extremely Difficult to forge something like a six throw crank shaft with seven Main Bearings. The grain flow you refer to is not ideal either in that application as it is in a poppet valve where you an extrude the shape and jump it up to thickness it. Plenty of racing car shafts are from billet and the get a more balanced result as well. Aero shafts are often nitrided where stress reliving is achieved at the same time as surface hardening.. Crack testing is done new and at every rebuild. There is NO non destructive test for Metal fatigue. At some stage the Part should be discarded, "Lifed" or it was built far too heavy to be on a plane. .Nev

That is the Jabiru assessment of it... When considering the forces applying, you have to consider the larger order as being more significant. Potentially it's harmonics.. There will be a bad rpm SOMEWHERE on any engine. IF there's been a fault with SOME crankshafts and is Known that is a Quality control issue so fix that anyhow.. Gyroscopic forces broke Crankshafts in Croppy C-180's Pivoting on one wheel at High engine RPM. Nev

WE understand that by now. How many times have you said much the same thing? Nev

That is the Normal place to break. I think it's where the UL's normally DO as well. . Torsional vibration can do that. Having a flywheel on the other end and more mainbearings aggravates it. Might need dynamic Balance weights. You can't feel torsional vibration. IF a prop extension was doing that you would feel it. Nev

Depends on where they are breaking wouldn't it? Its one of the few AERO Engines with a Mainbearing on each throw. Nev

jabiru say it's variations in the heat treatment and replacement will be from solid billet fully machined. Engines are OK to 150 Hours so get in touch and schedule the work prior to reaching 150 Hours. Existing warrantees are extended to cover this. Nev

"Think AEROPLANE" . Don't 1/2 do anything on one. Nev.