Building the Felgiebel

[rweber]

Dear all,

after finish the Mono (http://www.homemodelenginemachinist.com/showthread.php?t=27456) I was looking forward to find a new project. When beeing at an exhibition I meet a guy that was showing an Felgiebel engine. It's supposed to be one of the first model engines available in Germany for home builders. Designed by A. Felgiebel at about 1939. The plans together with detailed building instructions were publishd in a book named Benzinmotoren und ihr Selbstbau, A. Felgiebel, 1939. I was able to buy a complete book from an ancient library to a moderate price.
Compared to the Mono, this design is completely different. While the Mono consists of about nearly 600 parts this two-stroke engine is an example for simplicity. But there is one challange: The crank case and cylinder head are aluminium castings. I've never done that before, but I always wanted to do. If someone is interested, here are a few pictues.

regards,
Robert

 

[rweber]

First i build a 3D printed model of the crank case, ground coated a grinded.

 

[rweber]

and put it into the sandbox.

 

[rweber]

but the results are not so bad for a first try

 

[rweber]

and milling the backside

 

[rweber]

and final internal turning.

 

[rweber]

and a Wohlhaupter is all you need :thumbup:

 

[Herbiev]

Coming along nicely

 

[rweber]

to the cylinder

 

[rweber]

cylinderhead's holes

 

[rweber]

and mill the ports

 

[rweber]

in the workshop. I should consider to install a better isolation

 

[rweber]

Casting was quite successfull, I have got five good crankcases. I took the best three of them. But building three identical engines would be boring. So, here are my variations. On the left side, the watercooled version, in the middle my own idrea and on the right side, the original as described in the plans.

 

[Mechanicboy]

Hi, is it not too high transferport and too low exhaustport in the sleeve?

 

[ZAPJACK]

To help you in this nice project, here is a couple of pictures of the Felgiebel
Nice job !
LeZap

 

[Mechanicboy]

Now i can see the exhaust port is in other side of the cylinder.

 

[rweber]

To help you in this nice project, here is a couple of pictures of the Felgiebel
Nice job !
LeZap

Thanks for providing that pictures. You mounted it on a nice stand :thumbup:

 

[rweber]

Now i can see the exhaust port is in other side of the cylinder.

Yep you are right. See the picture I attached, that shows the locations.

 

[rweber]

Does somboedy know, whats the purpose of this screw? Some Felgiebels have one, some not. And it is not drawn on the plans.

regards,
Robert

 

[Barnbikes]

Drain the crankcase if you ever flood it?

Some dirt bikes and snowmobile use to have them.