Yes I know that with the blade but on my mill that can cause me some trouble... And I need a blad with minimum 80-100 in diameter.... Not that cheap.
I try it that way if it does take to long I will do it with a blade.
At the end it doesn't differ that much if you mill slots like on your heat or open fins like my one.
The only sucking thing is the time because I can't go deeper than 1-1,5mm per cut

Made a start for 2 more. Due the left over material, cutting it and making both sides flat they are 5mm shorter than a normal head, that is no problem due the better cooling that I have noticed.

https://cimg6.ibsrv.net/gimg/www.rct...4500b55fc6.jpg
https://cimg0.ibsrv.net/gimg/www.rct...144122cc05.jpg


And beside this material I have a meter in 50mm diameter of 7075 aluminum to play with ;)

It took some time but a friend managed to startup his CNC machine and mill the slots.

https://tweakers.net/fotoalbum/image...SGa46J1yq6.jpg

https://tweakers.net/fotoalbum/image...5kjUwSbmnD.jpg

https://tweakers.net/fotoalbum/image...86a3u7FEJS.jpg

A clubmember is willing to get them anodized through his work and can do a laser engraving. To get the visual picture how the engraving looks like he made a 3D drawing of the head but gave it a much better design to it.

https://tweakers.net/fotoalbum/image...y6NQTTMLZe.jpg

https://tweakers.net/fotoalbum/image...DLX2oSAx0u.jpg

https://tweakers.net/fotoalbum/image...VJuv37LbWn.jpg

https://tweakers.net/fotoalbum/image...4lbphh53Az.jpg

https://tweakers.net/fotoalbum/image...KVQabPMgr6.jpg

https://tweakers.net/fotoalbum/image...GmOurg8tmJ.jpg

looks amazing roelof!!!!

now the backplate of the OS engine :D

Perhaps you could consider trying the concept with a mid range PC CPU heatsink and machine the appropriate dimensions and fit for the engine?

Save on materials cost, and would resolve my curiosity.

Just plain straight up fins is a bit old fasion but it works. You can take an old Pentium heatsink as a base and shape it as a cooling head but I think when you want to mill the fins in shape you have to fill up the space between the fins to support the fins when the mill is touching them. They could bend.

But there is no need to save money, it is just a personal hobby project with as result to run something different with my own modified engines. There are no plans for a mass production although people do contact me how to get one.

I have 2 of these, they were saved from the bin,

https://cimg5.ibsrv.net/gimg/www.rct...4aa411fb69.jpg

Can take out plenty of heads, and maybe I try one..

Ready from the anodizer, soon we will work on a laser engrave design...


https://cimg8.ibsrv.net/gimg/www.rct...e3ed1a5b31.jpg

A few days ago a friend who provided the anodizing had the time to draw a designe to be laser engraved.

He made a base which did I like. With a chat over MS-Teams we discussed and made the changes and filled up all blank spots and on my screen I could follow his drawings.

We ended up with this:

https://tweakers.net/fotoalbum/image...MA3JtwQIT5.jpg

The only difference between Novarossi and me?
I make their engines look good!


https://cimg9.ibsrv.net/gimg/www.rct...3a20ac2121.jpg
https://cimg1.ibsrv.net/gimg/www.rct...eab9cb8c9b.jpg
https://cimg2.ibsrv.net/gimg/www.rct...060d3b9d5a.jpg
https://cimg3.ibsrv.net/gimg/www.rct...4a8d63717d.jpg

It looks well made,, and the vertical fins should do a good job of extracting heat directly from the cylinder head, but I question other parts of the design. The directional fins require airflow to be precisely front-to-rear for proper cooling, which cannot be guaranteed if the engine is shrouded by a body shell; airflow within the body shell is turbulent, even with ventilation ports cut into the shell. Also, the solid top plate will restrict airflow a little bit as compared to having an open top, for no obvious gain.

The head sticks out the body, no issues there. Even when the glowplug is leveled below the body linethere will be enough space for the flow to bend off or vortexes to reach the glowplug where with normall horizontal fins and a small tree trunk in the middle it will be much harder to get enough flow to the glowplug.
I left the upper part closed to keap the head more solid but flowing air picked up by the head is now forced to flow through the head and can not bend up. And it gives space for some graphics ;)

https://cimg5.ibsrv.net/gimg/www.rct...b817413d4b.jpg


Offcource I have no simulation software to get proof of my thinking but when you look at some heads like the MAX engines you can see the fins are with a small angle facing down to the center of the head so airflow is forced down to the glowplug

Ah, I didn't know the heatsink was entirely above the body. Should be no airflow problems then.

You might want to acid-etch the heatsink before anodizing it. A rough textured surface can increase the effective surface area by as much as 50% because of all the tiny bumps and pits. Even though the air passing across those tiny bumps and pits will be moving (relatively) slowly due to boundary layer adhesion, that slow movement will actually give the air more time to absorb heat before exiting the rear of the heatsink. Air is a poor conductor of heat, so every little improvement is worthwhile.

I run my bodies on the rear mount in the lower position, most run it on the higher position which I believe will raise the body by 10mm. Then for shure the glowplug is placed below the body line.

About rough surfaces making vortexes slownig down air you are probably right bur fast flowing air will bring more fresh cool air. Also rough survaces wil hold dirt much easy blocking a heat transfer to the airflow. And yes, a normal start of anodizing is an acid bath to clean the surface, when doing at home we use car battery acid from the car parts shop.

I am busy making a vibrating machine with stones or I will get cracked nut shells to polish the parts I make.

There would still be fast-moving air in the middle of each pair of fins. Only the air touching the surface of the fins that would slow down, and I think that would be beneficial because it would allow the air touching the fins more time to actually absorb heat. You have a point about dirt reducing heat conductivity, but anodized aluminum has a microscopic honeycomb texture anyway (that's what the colored dye soaks into), so I think some dirt adhesion will be unavoidable; the heatsink will have to be cleaned regularly for best performance, no matter what.

Ultimately the only way to know exactly how those factors would affect this specific design would be to make multiple heatsinks with slightly different surfaces and test each one in identical conditions. Whether it's worth doing all that work for a hobby, I don't know.

Are the fins acting like an extra wing ?

Good question
I think not. Due the 13mm center hole and the 4x 8mm screw holes most of the fins are no one piece long fin on the inside.
Maybe a top level driver can notice a difference?

Before you know it it has been a rabit, producing more.


https://cimg4.ibsrv.net/gimg/www.rct...d1b5c4e805.jpg

did u test these? how much cooler? and did it do anything to the handling of the car?

My 1st ever head was 5mm higher and could notice just a few degrees lower temp, that is why I made these 5mm lower.
I have runned last season with the 1st lower version and so far no issues at al. Do they run better? I do not know. If they do provide a tiny bit more cooling you can go a tiny bit leaner on the tuning.....
Do the fins help as a kind of tail fin? maybe.... I am not of that caliber to notice, for me it is more a personality thing with the tiny advantages on the background. Also the straight up fins will give all the room for the airflow to bend off to the glowplug while with the normal fins and the higher placed bodies it is a bit difficult.

Soon one of the heads go to a guy who is able to notice the difference.

After a long time and one bad attempt to get the heads laser engraved (the guy who wanted to do it suddenly passed away last xmas) they are now laser engraved. A colleague is experimenting with an home build cutter/engraver and after some tests on anodised plates he was willing to do my heads.

https://cimg5.ibsrv.net/gimg/www.rct...2325a32820.jpg

https://cimg6.ibsrv.net/gimg/www.rct...527d8ed5cd.jpg

Very nice.

They look really good man.

Awesome!

Nice Explaination
 

Thanks for your kind information. It will surely give me important knowledge. I will look forward from it surely.