The Incident - fixed the audio at

This is what happened to my Lancair back in 2019. This incident caused me to learn a lot about the design, and its evolution

[@williammcbane2599]

Thanks for the info. Sorry about the incident, but glad you are ok, and that this has allowed you and mfr to discover some “opportunities for improvement” to the design. Wonderful airplane.

[@andrzejcwirzen5623]

did you open the engine to check the crankshaft or just looked/measured the prop flange?

[@jonasbaine3538]

So with this stronger nose wheel fork where will energy be transferred to next in a hard landing? Would entire nose gear now go up into airframe?

[@user-ej9jq2zf1y]

Just wondering if it was a good thing that this was the weak point to fail instead of a more significant component??? Just a thought if this sub-designed part would not have failed would something more serious might have occurred?

[@daleolson3506]

Are you a left lane camper?

[@N91CZ]

Did you measure the hardness of the original fork? If not and you still have it, I would be happy to measure it. One benefit to a softer fork is that it will absorb more energy and transfer less to more expensive parts like the strut and the engine mount. The trick is to find the right strength level to break the cheaper parts first. That replacement fork is what they use on the Legacy just drilled with smaller holes, 1/4" vs 5/16".

[@Lancair320]

Hi Chris. My mechanic had it. I'll have to ask him if he's still got it. The biggest thing that got me was just how much the new fork was beefed up. I'd say it's a good 30% bigger in just about every dimension. On a somewhat related note, the nose hydraulic cylinder ripped out of the top of the well last weekend. I'll have to make a video about it, but the short version is it appears the builder didn't properly adjust the closed stop travel. Just off enough to slowly break the glass over a couple of hundred cycles.

[@N91CZ]

@@Lancair320 yeah saw the vid last night. Bummer. The new fork is beafier because Lancair simply took the Legacy fork and drilled it for the 360. They didn't want to stock two different parts. If you find the old one, I would be glad to measure it for hardness.

[@MikeToomey]

Where did you find the replacement prop? I bought a Lancair 320 with collapsed gear and prop strike. Can’t find a new prop. Also, how did you determine if engine needed disassembly & inspection?

[@Lancair320]

The prop is a Whirlwind RV200. It’s designed for Van’s RV aircraft. If it works for them, it’ll work better on a Lancair, and it performs beautifully. Beats the old Hartzell hands down. As for the tear down, I spoke with several A&P/IA mechanics. They had the same opinion: the flange on the crankshaft is the weakest point on the drive train. It is virtually impossible to damage the internals of the engine without damaging the flange. Therefore, check the runout on the flange, if it’s in specs the rest of the engine is fine. Lycoming engines have a runout of 0.005 inches. I checked the runout on mine 6 times to be absolutely sure. The worst reading I got was 0.003 inches, the best was 0.002 inches, well within limits. Since it’s experimental I made the call to not tear it down. Over a hundred hours later and it’s still performing wonderfully.

[@MikeToomey]

@@Lancair320 Awesome info, thanks for the quick reply. I also dialed my crank many times to be sure and most common reading was less than .001”. I will check Whirlwind props, although the price willl likely go up since Hartzell bought them. Love your Lancair videos. Thanks again!

[@DWBurns]

How long did it take to get back in the air?

[@Lancair320]

About 6 months. I wasn't in any hurry, wanted to make sure it was fixed properly and the plane was safe.

[@alk672]

Just curious - what was the METAR at the time of that landing? Glad you're ok.

[@Lancair320]

That was so long ago that I honestly don't remember. It was nothing of any concern, that's for sure. And the FAA agreed. If the fork hadn't been the way it was, it just would have been a hard landing and no big deal.

[@deani2431]

What implications ie: the prop strike?

[@Lancair320]

My last reply got corrupted, weird. Anyway, short version: engine was good, didn’t need to be rebuilt. Rear bolt and gear was replaced, runout is well within specs. Half a dozen oil changes / analysis and 200+ hrs later and it’s running great.

[@1jagman]

@@Lancair320 just curious the picture of the nose wheel at the end of the video is that with the new fork or is that the old fork?

[@Lancair320]

@@1jagman That's the new fork. Much larger than the old fork.

[@1jagman]

Thank you!@@Lancair320

[@louisvanrijn3964]

Nose fork issues? Made of 2024 ? Heat it to 440 C for 30 minutes, dip it in water after that. It has a low yield strength for say 1hour increasing to the full strength in three hours. Bend it back. Check for cracks after that. Another possibility for a skilled home builder is to laminate the same design to a 1.5 more plate thickness in carbon fibre. Use a substantial amount of UD in vertical direction and a large radius.

[@Lancair320]

I'm no expert on heat treating, but I will say that Lancair Uvalde had to work out how to properly treat the new forks. The instructions they had from Oregon didn't work. Or at least they weren't happy with the results.