Dan Gurneys New Engine

[strad]

I have read a couple of articles about Dan Gurneys new engine but I have not seen any comment here about it.
http://www.momentcancelling.com/
With the implications for motorcycle use I thought J.A.W. might have some thoughts.

[Chuckjr]

Wow the output numbers look impressive. Nice work Dan!

[bill shoe]

I've heard of "4-square" engine configs before which involve two parallel crankshafts, so I don't know what would be innovative about this one. Perhaps they were the first to submit a patent specifically for a narrow two-cyl version.

Don't buy the smooth-as-a-turbine thing. Yes, the two-cyl has nicely balanced reciprocating components, but the torque output pulses will still be very large. You have one 900 cc cylinder firing every 360 degrees of crank rotation and unless they use a monster flywheel they will have valleys of negative torque in between the firings. This is the same (approximately) as on any large displacement 2-cyl engine. The large torque fluctuation will cause the engine to pitch strongly at the cylinder-firing frequency.

I've just reduced my chances of being invited to Gurney's next birthday party. From 0.0000023 to 0.0000017.

I recently saw one of the actual Gurney F1 cars in the Indy museum. It was stunning to look at, the best looking race car I've ever seen, seriously. This puts me back to 0.0000023.

[Tommy Cookers]

this looks rather like the layout used on the just pre-WW2 Velocette 'roarer' supercharged racer and their road prototypes (model 0 ?)
intended to eliminate gyroscopic moments disturbing in yaw a longitudinal engined-shaft driven machine subject to pitching over bumps
unfortunately such machines are subject to drive torque reactions disturbing in roll with wheel hop over bumps
and the 2 cranks geared in contra-rotation each with 100% counterbalance weights, pistons co-phased
cancel all primary frequency engine inertial vibration (forces and moments) but secondary vibrations remain (as with a square 4)
like the 1977 Kawasaki 250 and 350 cc simultaneous-firing 2 stroke disc valve racers that won WCs in 78 and 9 etc
(though originally with conventional balance factor and antiphase piston positioning/firing that produced lots of vibration)

I haven't read the patent, but we know that (unlike DG's engine) .......
other parallel twin engines with primary counterbalance shafting of normal simplicity and compactness have a residual moment imbalance

EDIT -
the 2 gyroscopic torque reactions in cornering are changed relative to the conventional layouts ie .......
mainly on corner entry, the favourable yawing moment (with conventional forward engine rotation) is eliminated
mainly established in-corner, the unfavourable (overturning) rolling moment is eliminated, so slightly less lean angle is required

an unimportant torque reaction (to rotational acceleration of engine parts etc) is changed relative to the conventional layouts ie ...
internal torque reaction (apparent throttle-tweaking a stationary machine but also occuring in a moving machine) is eliminated -

but ( I think at this moment) ....
the more important (external) drive torque reaction (road reaction to the changing rear wheel torque throttling or shifting when moving) is unchanged
as Velocette (above) later decided in 1939
though this is not a real problem with the transverse crankshaft orientation as the DG machine


btw - DG's website commendably tells us that the Gurney flap was previously invented in Germany in the 30s, so wasn't patentable by DG

[J.A.W.]

I have read a couple of articles about Dan Gurneys new engine but I have not seen any comment here about it.
http://www.momentcancelling.com/
With the implications for motorcycle use I thought J.A.W. might have some thoughts.

Well strad, to be frank, it looks oddly Lanchester-like..
Ol' Dan has come up with a few off-beat bike ideas over the years..

I cant see the big ol' V-twin cruiser brigade - being much interested, its got no V-style, & no 'potato-potato' exhaust sound..
Nor will the big-as bagger mob likely see it as a 6 cylinder substitute..

& whatever happened to that American big V4 bike - basically engineered on 1/2 a NASCAR mill?

[langwadt]

isn't gears like that a recipe for trouble?, I image even the tiniest backlash and it is just going to hammer it self to pieces

[markc]

Looks like there's lots of work put into the intake side, trying to deliver air deeper into the combustion chamber.

So standard straight intake = 141hp
Special "double tapered" intake = 262hp
Same engine otherwise.

Peak @ 8000rpm @ 9.5:1 compression

From here:
http://www.gizmag.com/dan-gurney-moment ... ent/39344/