Radial engine sport bike
With the recent mention of the radial engine project going on down under, you start to wonder what the guys building radial engine customs have been up to. The guys at JRL Cycles, who have now put together a number of bikes around the 9 cylinder Rotec radials, are working on several projects, including an 18 cylinder two row version which should be quite a sight.
While prowling around their image gallery, I spotted the drawing above, a 7 cylinder radial engine sport bike. Is this something they're thinking about building? Considering the size of the Rotec, the 7 cylinder is only about an inch and a half less in diameter than the 9, it seems unlikely unless there's another smaller engine available and unless air flow could be managed very well it would lead to some cooling issues, but at least someone is thinking about it and it shows possibilities beyond the stretched customs we've seen so far. Interesting.
Link: JRL Cycles
UPDATE: Kim Scholer sent in this photo he took of a Verdal radial engine motorcycle at the Sammy Miller museum. It's a 750cc 5 cylinder single speed board racer. Thanks, Kim!
Verdal 5 cylinder radial engine motorcycle
{ 12 comments… read them below or add one }
If you’re going to blow a cylinder head, let’s hope it’s not the one at the front of the saddle.
This is trruly one of those case of, “sure you can but, why would you?” Personally, I’d like to see them use an R-4360 radial. That would get your attention.
Mel Beaty
I don’t really think that qualifies as a design study, since there’s valvegear that overlaps the front tire, and the swingarm pivot seems to intersect a cylinder head. And that one cylinder is certainly a crotchroaster.
Neat brainstorming sketch, though.
I wonder how much space that setup leaves for fuel? How about whittling a 9 cylinder down to a radial triple?
As cool as that is I’d rather see a purpose built wankel engine or jet turbine specifically for a bike. The MTT Y2K was overkill by quite some margin and there has been nothing really in regards the wankel in the last 20 years.
Where does the transmission go?
I’ll echo the concern about the crotch-piston. Also, considering the space concerns previously mentioned, it seems like the crankshaft takes up far too much room.
Plus, considering the number of cylinders, it would probably put some fairly big constraints on the total displacement of the bike, and obviously the more reasonably sized the individual cylinders are, the more ridiculously unreasonable the whole engine would be.
Well it’s a new one!
I wouldn’t read too much into it, the sketch underneath is just a copy of a ‘how to render a motorcycle in photoshop’ tutorials that’s been doing the rounds on various design websites for years.
Like yippy little dogs, some things should not be allowed to live. This is one of them. In short: BAD CAD.
NVUH
This looks to me like the kind of sketch you make when you ask “what if…you put a radial engine in a sport-bike?” The answer pretty obviously is “This, and that’s why you don’t want to do it.” Clearly, the radial engine does not fit well in a motorcycle application. Looking at the sketch does start to show why singles, inline multis, and Vees (“L”s for the ducati fans), are the engine configurations of choice for motorcycles. You engine builders out there, if you want to be different, how about a transverse “W”? Moto-Wuzzi, anyone? Or use the balancing scheme from the Ducati supermono to smooth out things in a parallel twin! I would think those would be more fertile grounds to explore.
If Jimmy Stewart had ridden one of these, that scene in North By Northwest might have been even better.
Great to see what people come up with using a bit of imagination.This one looks like a design to barbeque the rider ,the heat given off would be unbelievable. And what about the gyro forces involved when cornering.
I was thinking of slipping a Boing 747 jet engine into a bike.Now that would be interesting !