Well then, really off topic...

conehammer · 04-15-2010, 01:17 AM

Here is an update covering what I've been up to.

A video of my first scratch built gearbox test under power. This is a braked differential type, planetary differential as the core.
The power is via centrifugal clutch. The engine is an O.S. Engines FS-20;.20 cid / 3,5ccm 4 cycle.
The clutch was machined from D2 type tool steel. The gearbox housing is made from .250" 7075 aluminum
plate; the ball bearings used and gears are all stainless steel. The remainder of the bearings are oilite type.The cover is
.250" acrylic fitted with a screw cap to add oil. The gearbox presently has better than .500" oil bath; I am using
Sta-Lube air tool oil. I will reduce the oil level after tests are complete.

As you can see this was truly an example of a "Jerry rigged" test setup; I wanted to test the gearbox but did not yet
want to commit to using this starter assembly; so no permanent mount was made.

http://www.youtube.com/watch?v=5_YHZLUItVI

At the end of the video you'll hear me exclaim as I burnt the middle finger of my left hand just after disconnecting the fuel line. The
exhaust stacks on model 4 cycle engines get quite hot!

All in all a very good test, even the clutch disengages when I want it to... I will take a break for a while then move on to the installation
into a model.

Since the video was made I've finalized the starter and most of the shift interface. I will begin on getting it mounted in the target model: a 1:10 Hetzer.

For the complete development story please refer to my website, http://tanks.linite.com/ under the gearbox page. At the bottom of that page.

Jerry

04-15-2010, 01:17 AM	#11
conehammer User Join Date: Jul 2007 Posts: 116 Thanks: 1 Thanked 55 Times in 21 Posts	Here is an update covering what I've been up to. A video of my first scratch built gearbox test under power. This is a braked differential type, planetary differential as the core. The power is via centrifugal clutch. The engine is an O.S. Engines FS-20;.20 cid / 3,5ccm 4 cycle. The clutch was machined from D2 type tool steel. The gearbox housing is made from .250" 7075 aluminum plate; the ball bearings used and gears are all stainless steel. The remainder of the bearings are oilite type.The cover is .250" acrylic fitted with a screw cap to add oil. The gearbox presently has better than .500" oil bath; I am using Sta-Lube air tool oil. I will reduce the oil level after tests are complete. As you can see this was truly an example of a "Jerry rigged" test setup; I wanted to test the gearbox but did not yet want to commit to using this starter assembly; so no permanent mount was made. http://www.youtube.com/watch?v=5_YHZLUItVI At the end of the video you'll hear me exclaim as I burnt the middle finger of my left hand just after disconnecting the fuel line. The exhaust stacks on model 4 cycle engines get quite hot! All in all a very good test, even the clutch disengages when I want it to... I will take a break for a while then move on to the installation into a model. Since the video was made I've finalized the starter and most of the shift interface. I will begin on getting it mounted in the target model: a 1:10 Hetzer. For the complete development story please refer to my website, http://tanks.linite.com/ under the gearbox page. At the bottom of that page. Jerry