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Chogy
03 May 09,, 17:06
I'm really enjoying seeing the variety of modeling skills by the members here. Years ago, I took up a hobby that has always been popular especially with the British... home metalworking, using lathes, mills, and other machine tools.

Being an airplane nut, I have always admired the large air-cooled radial engines of WW2. They make a beautiful, unique sound that cannot be mistaken for an inline engine, and they proved exceptionally durable in combat. I decided to create an operating radial in miniature, and mount it on a "test stand" that would allow running demonstrations.

The bulk of the engine is aluminum, and the heads, rocker boxes, and rear cover were sand-cast aluminum. The cylinders are steel; rings of cast iron.

For run-in purposes, and to check timing and function, near the end of the project, I mounted the entire engine in my lathe:

http://www.5bears.com/radpics/runin03.jpg

The stand and mounting took a while, but I am pleased with the result:

http://www.5bears.com/radpics/fnl02.jpg

It is not a copy of any particular engine... it has a vague similarity to a generic 9 cylinder Pratt & Whitney engine from the 1930's.

Anyone else into metalworking? Steam engines, etc?

Parihaka
03 May 09,, 22:09
Wow. That is just fantastic.

bolo121
04 May 09,, 06:34
Very cool. Do you have any videos of it in operation.

Nord
04 May 09,, 10:08
Amazing skills!

tankie
04 May 09,, 11:31
1St class ,well done;)

Knaur Amarsh
04 May 09,, 13:28
That looks awesome, how much mW does it make?

Chogy
04 May 09,, 14:20
Thanks for the kind words. I've never measured power output. It swings a 20" variable pitch (ground variable) prop at about 5,000 RPM max, and will idle around 800. In terms of power to weight, it is nowhere near the types of commercial engines guys are using on giant scale R/C airplanes, but it would probably be able to haul a Stearman or similar around.

I know I've got some movies somewhere, I'll try to dig them up.

texasjohn
08 May 09,, 23:23
Excellent work!

dave lukins
08 May 09,, 23:33
Fabulous engineering. A work of art:)

Knaur Amarsh
09 May 09,, 09:34
Thanks for the kind words. I've never measured power output. It swings a 20" variable pitch (ground variable) prop at about 5,000 RPM max, and will idle around 800. In terms of power to weight, it is nowhere near the types of commercial engines guys are using on giant scale R/C airplanes, but it would probably be able to haul a Stearman or similar around.

I know I've got some movies somewhere, I'll try to dig them up.

Really? Wow am surprised, Iv seen some really expensive RC crafts but never knew they are using engines that generate that sort of power. Your engine sounds pretty powerful too, I was assuming it to be one of those miniature 5hp scale models :redface:

Chogy
09 May 09,, 14:59
Really? Wow am surprised, Iv seen some really expensive RC crafts but never knew they are using engines that generate that sort of power. Your engine sounds pretty powerful too, I was assuming it to be one of those miniature 5hp scale models :redface:

That's OK Knaur. I gues the point I was trying to make was that I didn't have ultimate power/weight as a goal, at all, and during construction, did not work hard at keeping the parts lightweight. My primary goal was ease of starting and reliable running. A low idle, too... Radial engines do sound cool at idle. :biggrin:

Knaur Amarsh
09 May 09,, 18:32
A low idle, too... Radial engines do sound cool at idle. :biggrin:

Now then, can't be a tease and get away with it :cool: Post away a vid or sound file to let us hear it sing.

Chogy
10 May 09,, 13:20
I will try and track some down... its been a while since I messed with the recordings. I think I have some stashed somewhere.