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Speed,Combat,Scale,Racing => Speed Talk => Topic started by: rustler on February 02, 2015, 03:32:20 PM

Title: 4-Stroke Speed.
Post by: rustler on February 02, 2015, 03:32:20 PM: I hear a/some 4-Strokes have been flown in C/L Speed at the U.S. Nats.
Can anyone confirm and/or fill in any details?
There are some faint stirrings for this over here in England.
Title: Re: 4-Stroke Speed.
Post by: bob whitney on February 02, 2015, 04:33:46 PM: it has been a while but i remember someone flying a 4 stroke at the nats ,dont remember what class it was but was just for fun
Title: Re: 4-Stroke Speed.
Post by: Bob Heywood on February 03, 2015, 06:28:40 AM: Brothers Bill & Joe Franklin entered an OS 90 FS powered D Speed at a NATS some years ago. They did it just for the fun of it. As I recall the speed was in the 160's. I doubt that they did any work to optimize what they had.
Title: Re: 4-Stroke Speed.
Post by: bob whitney on February 03, 2015, 08:51:33 AM: thats the one
Title: Re: 4-Stroke Speed.
Post by: rustler on February 03, 2015, 01:16:22 PM: Interesting, thanks.
I thought D Speed was up to .65? Or is it 65 or over?
Are the Franklins still around?
Title: Re: 4-Stroke Speed.
Post by: Tim Wescott on February 03, 2015, 02:27:38 PM: Quote from: rustler on February 03, 2015, 01:16:22 PM
Interesting, thanks.
I thought D Speed was up to .65? Or is it 65 or over?
Are the Franklins still around?

At one point the AMA had a blanket 150% displacement rule for four strokes vs. two strokes, so a 90 would have been acceptable. I don't know if they still do that or not.

It might be interesting to go there, just to see what you could do with it. You'd need to do lots of cam grinding to get the speed potential up, and valve train work to keep the valves from floating.
Title: Re: 4-Stroke Speed.
Post by: don Burke on February 03, 2015, 03:57:51 PM: still there:
CL Speed rule
6.1: Sixty percent of the actual piston
displacement of four-stroke cycle engines shall
be taken for competition classification purposes.
Title: Re: 4-Stroke Speed.
Post by: Bob Heywood on February 03, 2015, 07:46:48 PM: Quote from: rustler on February 03, 2015, 01:16:22 PM
Interesting, thanks.
I thought D Speed was up to .65? Or is it 65 or over?
Are the Franklins still around?

I have not had contact with the brothers for quite some time. They were not serious C/L Speed fliers but like to dabble in a number of different aspects of the hobby.
Title: Re: 4-Stroke Speed.
Post by: Motorman on February 04, 2015, 08:37:06 AM: What about wankle speed.

MM
Title: Re: 4-Stroke Speed.
Post by: rustler on February 04, 2015, 01:21:23 PM: Much appreciated everybody, thanks.
Title: Re: 4-Stroke Speed.
Post by: Joey Mathison 9806 on February 06, 2015, 04:18:11 PM: i remember that flight. it was slow but a good flyer. looked like a regular 1970's style speed job. very easy to keep up with.
Title: Re: 4-Stroke Speed.
Post by: Dane Martin on March 16, 2015, 04:12:29 PM: So if i wanted to build a speed plane with my YS53FS super, that would be like a 32-35 sized 2stroke. That's an idea.... >:D
Title: Re: 4-Stroke Speed.
Post by: Joey Mathison 9806 on March 16, 2015, 09:15:48 PM: the 4 stroke d speed at the 99 nats that I flew for the franklin brothers recorded a 115 mph flight.