Zimmerman Disk intake .21

[lohring]

You can easily cut away the backplate under the drum so the only close fitting area is around the intake port. We did some experiments with 26 cc engines where we reduced the clearances around the crankshaft as much as possible. We lost power despite the increased crankcase compression. Many designers of larger engines believe you need at least 1 mm (.040") clearance. Zimmerman disks have a lot of surface as well unless properly designed. See the Aprilia disk below as an example of viscous drag reduction.

Lohring Miller

 

[dwilfong]

You can easily cut away the backplate under the drum so the only close fitting area is around the intake port. We did some experiments with 26 cc engines where we reduced the clearances around the crankshaft as much as possible. We lost power despite the increased crankcase compression. Many designers of larger engines believe you need at least 1 mm (.040") clearance. Zimmerman disks have a lot of surface as well unless properly designed. See the Aprilia disk below as an example of viscous drag reduction.

Lohring Miller

RSW250 inlaat.jpg

Lorhing what is the rotation of the disk in the pick when looking at it CW or CCW?

 

[Anders_Martinelle]

Chris, why not make it youself??
Take the disk from a RS45 and make youself a "backhousing" and slam it on to a CMB 67 for example and............ .

I have had that in mind to do to a VAC 91 and take the disk from the RS91.

Not so hard to make.....
Who know`s, Winter is coming......

Buy the way, a PEEK drum to a VAC 21 is around 2-3 gr...

Anders

 

[dwilfong]

http://www.mhz-powerboats.com/IC-Engines/engines/VOK-90.html