Since SSW is no more and Len doesn't seem to be here, I was wondering if anyone knew the mods he did to the FP 35's that gave them the power he seemed to get from them?

Best,   DennisT

Id thought his blurb on the comercial site ( Stuka Stunt ) mentioned a ' Hemi Head ' . ? ( as well as the blocked bypass ) anyone got one ? .

They managed to loose a Gardner ABC FP 40 piston / liner set too . Tho I now believe it was taken off their hands by persons from north of the border / State Line . Some seem to be on the giggle juice , or been in the sun to long .If not both .

https://www.worthpoint.com/worthopedia/os-35-fp-len-neumann-stuka-stunt-l-1952906423

Theres one there with semi obliterated text / instructions .

Maybe the head was like this?

Dave, the heads I had modded here in Australia used the early spec.

I bought six Tower 40 heads and had them all modified to the early drawing about 16 years ago.

I installed one on a late (ABN) FP40 which runs as sweet as with the standard FP (3.5mm dia) NVA and the standard FP 20/25 (6.55mm dia) venturi.

I still have four more ready to install — with a NIB Tower 40 among the engines destined to see s new head.

I gave one to Matt (Air Ministry) and posted it to him in a little padded bag from Australia Post. It never turned up at his address about 100 miles from me. :-(

Dave - the first generation (PDF) was my starting point. It worked well but something else needed to be done.
The hand sketch that incorporates the 5 degree upward angle of the squish band and breaking the sharp edge made a very noticeable difference. The break from fast four cycle to two cycle was more pronounced and seemed to be a bit more powerful. At least, that's how I perceived it.
Give it a try. I did this mod for a number of people and all feedback was positive.
I've done this on a quite a few engines including the Brodak 25, the FP 35 and 40, the LA 40 and 46, the Super Tiger stunt 35 (bushed case and baffle piston) and the K&B 40

Bob Z.