Building the Felgiebel

[Pierkemo]

Whaaawww, very nice build!!!!!
Also very wel done, the castings!!

Pierkemo

 

[rweber]

Next part is not so easy to build, the contact spring.

Starting with this:

Bending around several times ...

after harden, temper and sandblast it looks like this:

finally assembled contact:

 

[rweber]

Next part to build is the fuel tank.
I do not like sheet metal work that much But it has to be done. The tank is build of a 0.25 sheet of brass.

First I made a helper tool for forming the caps. The sheet has to be annealed several times to punch it around the radius.

Soldered togehter:

 

[Mechanicboy]

Better to create the tank cover with metal spinning method, it's fact much easier and more beautiful than hammering the edge of tank cover. You can do it on lathe. The brass sheet must be annealed to be soft to form on pattern. See this movie how to spinning the parts..






Here is the info about metal spinning..
https://en.wikipedia.org/wiki/Metal_spinning

 

[rweber]

You are absolutely right. This will be a much better approach. I never could motivate me to create the nessecary tools needed for spinning in the past. Did not need them often in the past. But in the time I spent knocking with the hammer I would already have built them. You make me start thinking...

 

[rweber]

OK, I took the time to create some metall spinning tools for me.
Now the result looks significantly better than my first try.
Thanks to Machanicboy!

 

[Mechanicboy]

The fuel tank cover look much better and beautiful!

 

[777engman]

How about some photos of the tools you made for spinning?
Regards
Dean

 

[rweber]

How about some photos of the tools you made for spinning?
Regards
Dean

Sure, here we go:

 

[rweber]

Some carburettor parts

 

[rweber]

Some gastank parts

and a mounting plate. Used for drilling the careburettors holes and later as testbench.

 

[ixb1]

But the result was very disappointing.

It looks to me that the Alu was not able to push out the ambient air. Perhaps I filled it in to fast. I don't think the Alu cooled to fast, it came out very "liquid" from riser. Alu was at 700°C, the mould was pre-heated to 200°C, I used some salt as flux and wash soda for degasing.

I'm not sure where the problem resides. Maybe there is more than one
Or it is even not possible to make it this way

Any comments and suggestions are welcome!

cheers,
Robert

View attachment 94880

Hi
Maybe possible solution is simple mold by imprint the head pattern horizontally into sand with fins oriented down.

 

[rweber]

Hi
Maybe possible solution is simple mold by imprint the head pattern horizontally into sand with fins oriented down.

Also tried this way, but the gravity produces to less force, to press the alu down and let the air come out. The result was not better as in the picture you quoted. Perhaps it would work, if you fill the alu very very slowly, but then it would cool down until you are finished.
Now I'm thinking about a simple centrifugal cast mechanism... I know, the head can be simply milled and turned, but I'm interested if I can get it done this way.

 

[ixb1]

Is acceptable head with thicker wedge profile fins like on old Enya or McCoy engines?

 

[rweber]

Finally I decided to build the heads from a round bar, to get this project done.

 

[rweber]

Ok, alle the parts are completed. Now putting it all together ...



This is the watercooled version, also described in the book.



This is the "original" version from the book:



This is my personal version, some slight modifications. A longer intake tube and a "tuning" head with higher compression. I'm curious to see how it will run ;-)



The whole Felgiebel family:



and from behind:



Can't await to see them (homefully) run.

More to come....

 

[rweber]

Jippie, they are running. All of them ;-) I did two short vids if you want to see. They can be found here: https://www.homemodelenginemachinist.com/threads/finished-my-felgiebel-project.30741/

Merry Christmas!

 

[Billitmotors]

Would you have a copy of the STL file for the crankcase that you would be willing to share?
Rob.

 

[rweber]

I sent you a PM.

 

[Pierkemo]

Hello Rweber, yes i like to receive the STL for the crankschaft. Many thanks, Pierre