18cc V8

**Pixie** · 28th June 2009, 09:41

http://www.moyermade.com/chevyV8.html

**AllanB** · 28th June 2009, 09:52

Most impressive. A seven year project!

One question I have on these scale engines - the original full size donk revs to maybe 6,000, but the scale ones always seem to rev a lot higher. Anyone reason why as the bore/stroke etc are set in prefect scale so why don't the engines have the same limits?

**Pixie** · 28th June 2009, 10:06

Originally Posted by AllanB

Most impressive. A seven year project!

One question I have on these scale engines - the original full size donk revs to maybe 6,000, but the scale ones always seem to rev a lot higher. Anyone reason why as the bore/stroke etc are set in prefect scale so why don't the engines have the same limits?

Reducing the scale of a mechanical system drastically alters some of the forces operating on the system.

An example is the behaviour of air around a beating insect wing - at that scale the air behaves more like treacle than a gas.

**cs363** · 28th June 2009, 10:33

Impressive work, though personally I'd be a bit dissapointed that it sounds like a sick chainsaw - these guys seem to have got that aspect a bit better sorted:

http://www.nvbackflow.com/inprogress/V-8.mpg

**xwhatsit** · 28th June 2009, 11:58

I've been looking at these on Youtube recently. What really impresses me is the aero engines --- this is a 14-cylinder double-row radial:

The tiny little V8s and V12s... someone needs to make one about 50cc then mount it in an SS50 frame and register it as a moped

**cs363** · 28th June 2009, 12:18

Originally Posted by xwhatsit

I've been looking at these on Youtube recently. What really impresses me is the aero engines
The tiny little V8s and V12s... someone needs to make one about 50cc then mount it in an SS50 frame and register it as a moped

Yeah, it's amazing how many of these wee beasties are out there - I've been noticing quite a few of these popping up of late as well. Did you see the guy that hand built an entire Ferrari 512 in scale -all working, it was on Top Gear a while back:

20,000 hours....... farkin ell...

**Big Dave** · 28th June 2009, 18:18

It's a Pixie thing yeah? :-)

**smoky** · 28th June 2009, 18:31

Imagine if these clever bastards actually put the same effort into something useful

**peasea** · 28th June 2009, 21:22

Originally Posted by cs363

Impressive work, though personally I'd be a bit dissapointed that it sounds like a sick chainsaw - these guys seem to have got that aspect a bit better sorted:

http://www.nvbackflow.com/inprogress/V-8.mpg

I think nitromethane and a blower might have something to do with it.

**Laxi** · 28th June 2009, 22:19

Originally Posted by smoky

Imagine if these clever bastards actually put the same effort into something useful

you mean like a 50cc busa?

**EJK** · 28th June 2009, 22:55

If it's 1/6th Scale of a 365hp engine... Should it output 60.83 hp? That's alot!

**JMemonic** · 28th June 2009, 23:01

That Ferrari is amazing, seems to be some folks passion to build these things, gotta say though the radial does it for me.

**EJK** · 28th June 2009, 23:08

There was also a web site about a handbuilt home made Lamborghini Countach?

http://jalopnik.com/5065896/hand+mad...s-light-of-day

Some insane, talented and commited people out there.

**Bass** · 29th June 2009, 12:59

Originally Posted by AllanB

Most impressive. A seven year project!

One question I have on these scale engines - the original full size donk revs to maybe 6,000, but the scale ones always seem to rev a lot higher. Anyone reason why as the bore/stroke etc are set in prefect scale so why don't the engines have the same limits?

They actually have very similar limits but they are in terms of piston speed and more importantly piston acceleration which is mostly what determines the component stress levels.
As the size drops, so does the acceleration and so for the same stress levels, the revs can go up.