Honda V5

[coaster]

This design follows on from their V4, a V6 was also evaluated.
I am interested in the crankshaft, the balance factor seems high, also, the odd middle cylinder seems to have roughly the same counterweight mass as the two outer V twins.
Do we have any afficinadoes who have studied this design?

[Tommy Cookers]

... the balance factor seems high ....

RC211 I presume

the balance factor will be c. 100%
(much bigger than eg counterweights on inline 4 - because these aren't used for balance)

engine frequency force balance is 97% complete (and due to symmetry moment balance 100% complete)
no V5 has complete balance (only a v12 does) - V5 force balance could be complete but moment balance not

the 4 and 5 were subject to 145 kg minimum weight - but the 6 to 155 kg

EDIT with hindsight .....
yes when we know the single pin offset angle is 104.5 deg we can see there's 100% balance at engine frequency
but there's substantial imbalance at twice engine frequency (secondary imbalance) and .....
the single pin imbalance must be rather large ?

[saviour stivala]

RC211 - Honda V5. ''The fifth piston (the middle position of the three piston bank) had a rod journal offset 104 degrees from the other journals, the three piston bank was the front, the two piston bank was the rear, the rear piston rods rode on the outer journals next to the outer front pistons rods, this created a perfect primary balance in operation, much like that of an in-line six''.

[Robbo]

Driving 4 answers on Youtube has an excellent video on it.

[Holm86]

Driving 4 answers on Youtube has an excellent video on it.

Yes

[Tommy Cookers]

the excitable man in the above video is seemingly familiar with past posts on this forum

but he fails to mention that in this engine there is substantial secondary force imbalance
(just as in the current mandated F1 engine design and most F1 engines made in the last 60 years) ... and ....
he fails to explain that 'his' counterbalance weights are disadvantageously large

Honda has used the same design feature (76 deg pin offset) in road 52 deg V twin motorcycles for 40 years
Moto Guzzi used it 90 years ago in their 500cc 120 deg V twin racer (and reinvented flat-crank V8s c. 70 years ago)

Honda maybe had the same patent lawyers that Kawasaki used to patent the crossplane inline 4s ? .....
invented (and championship-winning) by German 'men in sheds' Fath and Kuhn over 50 years ago

[saviour stivala]

Honda's ingenious position of the 3rd crank-pin, coupled with the 75.5 degree bank angle made for a perfect primary balance, and an incredibly smooth-running engine.

[coaster]

The balancing mechanism is held in a case disposed on the left side of the rear cylinders.

https://freeimage.host/i/HbnPrWx

This balancing mechanism described seems to be a simple flywheel with mass concentrated at the perimeter.
I wonder if it is rigidly mounted, or has a means of oscillating much like an ilmor pendulum dampner?