I've often wondered how hard it is to retrofit props and hubs onto crankshafts meant for a different prop.

In this case, how would you go about mounting a 421 reduction gearbox or the TGIO-541 reduction gearbox onto the Audi engine? I haven't seen enough of the crankshafts and prop hubs across dozens of planes to really know how hard it is to swap props and/or gearbox.

Yes it would increase weight but I don't like his redrive solution. At all. With the amount of walk that belt had? No. Just... no.

And meaning to put it on a different airplane. Not on this. Just thinking of retrofitting the engine onto other airplane designs. IF it will tolerate the reduced lubrication additives that Jet A lacks versus Diesel.

Unfortunately, there's a whole lot more to adapting any reduction system to an engine and prop than attachment. Probably the biggest issue is the magnitude of the torque impulses which are significantly greater in a Diesel than any gasoline engine and this is even more critical if there's any chance that elasticity, resonance, or load reduction can allow the gear teeth to unload. Also AFaIK the required reduction ratio is much higher with the Audi engine than the aircraft engines you mentioned. This is a situation where the devil (reliability) is truly in the details.

Flies similar to most GA aircraft of the same weight class.

Takeoffs are a little different. Basically pull back a little on the stick and it flies off.

Landings are a lot different. I’m over the numbers at 75 and on the runway at 70. There is no flare. Once the mains are on, you fly the canard down until nose wheel contact. You land in pretty much the same attitude as you takeoff in.

Which is why I don’t think that the prop clearance is an issue with the Raptor.

I thought I heard him mention MOTEC for his ecu. Its one of the most robust units on the market, and heavily used in all forms of racing. I have no idea why he is using a separate switch to prime with a boost pump to start it. Makes no sense for that engine.

In an Audi when you turn the key on, the fuel pump pressurizes the fuel manifold. If his MOTEC isn't doing that, he's having to do it manually, but he's running it too long. Only takes about 2 seconds to pressurize those manifolds. They're not big.

That would be tough to do with the 421 gearbox (GTSIO-520), it's part of the engine case.

So, a sawzall to get it off the 520 and some JB weld and duct tape to attach it to the Audi. Actually, Peter would probably fabricate some brackets using another 25 lbs of steel angle.

It will be interesting how that redrive holds up. I wonder how many hours he has on it now? I just don’t see how it will hold up with it being fixed to the frame while the engine can move on the dampeners.

I got the feeling that he may walk away.

It would be a good floor display at EAA. He could deduct a couple of million

Wow, he didn’t have a fuel shutoff. Let’s put it in the worst out of sight place we can. It looks like he is trying to do something like the Cirrus side stick system now. I don’t understand why he tried to reinvent everything on this aircraft. If it didn’t violate some patent and it worked, I would have been using the idea.

https://youtu.be/9KuGgFG4pXk

From his videos, I’m guessing he’s driven the plane about 20 miles. :7)

From his videos, I’m guessing he’s driven the plane about 20 miles. :7)

Almost no Velocity's have a fuel shutoff accessible from the pilot seat.

It's one of the challenges with an airplane that doesn't have any fuel lines near the front of the cabin.