Interesting Alternative Engine?

[jhausch]

I don't know the weight and the transmission looks to be incorporated into the crankcase casting ,but this caught my eye....
"Triumph claims 147 ft.-lbs. of torque at 2,500 RPM"

http://www.triumphrocket.com/

[Frank Giger]

Interesting in that it's inline, but the liquid cooling gives me pause, as now one is dealing with a radiator.

[FlyingRon]

So what good is 147 ft-lbs of torque? To get the 140 HP you've got to have the have the engine wound up to 5750 RPM. That means gearbox if you want to drive a prop so now you've got a really heavy, liquid cooled engine in an awkward inline-3cyl configuration. I don't think it's going to replace the O-320.

I'm not even sure that engine makes sense on a motorcycle.

[Frank Giger]

It might be better to just go to a 2276cc VW with a redrive; 100 HP at 3800 RPM's, and it's aircooled.

Being inline does solve the problems that the typical twin motorcycle engine has with vibration, though.

The advantage of liquid cooling is that it will help with the demands aircraft requirements put on engines; they simply don't design them with the idea someone is going to routinely firewall the engine for a couple of minutes during takeoff, or gun the hell out of it on a missed approach for a go-around.

Plus we do this under the worst conditions for engines, as it's when there is the lowest amount of airflow for either air or liquid cooling.

It would look sweet under the hood of a scaled SE5a, though....radiator behind the prop and inline cylinders when one raised the side panels.

[FlyingRon]

Being inline does solve the problems that the typical twin motorcycle engine has with vibration, though.

Well, it actually makes different vibration problems as well as introducing a more complex transmission.

[jhausch]

So what good is 147 ft-lbs of torque? To get the 140 HP you've got to have the have the engine wound up to 5750 RPM. That means gearbox if you want to drive a prop so now you've got a really heavy, liquid cooled engine in an awkward inline-3cyl configuration. I don't think it's going to replace the O-320.

I'm not even sure that engine makes sense on a motorcycle.

I was thinking of direct drive and not going past, say, 2700. Not a 320 alternative, but a little smaller.

Weight is probably the biggest issue since it looks like the gearbox is integral to the crank case.

[FlyingRon]

At that engine speed you're only going to be making 70 HP or so. Of course, if the gear box is integral, you can probably leave it in second gear or whatever makes the ratios work out :)

[Frank Giger]

Yep, there's a Nieuport 12 out there with a motorcycle powerplant.....it gets put into second gear and stays there.

Gotta love any pilot operation that includes working a clutch to engage the prop before takeoff.

Depending on the plane, a belted redrive and a big prop might be the answer. I'm thinking low and slow aircraft, of course.

[Bob Dingley]

It sounds like the "Aero-Triumph" is a bit af a challenge. I also followed the progress of an "Aero-Harley" for a year and half untill the builder decided that it was not really coming together. Pity. Harleys sound so cool.


There have been some success in Europe with BMW motorcycle engines. There was an article in the Experimenter a year or two ago. I clicked on a few links and found a Luftwaffe pilot on a tour of duty in the USA and his project:


http://www.spang-air.de/e/html/bmw_-_engine.html


Neat engine. Light, fuel efficient, powerfull, dependable with oil cooled heads. Popular in Europe. There is a gent in Germany that makes PSRUs for the BMW and he says that he ships to US,. There is a shop in NJ that stocks gently used engines.