Tuesday, March 3, 2015

V2 fan hub assembly explained

Here's an e-mail thread I thought would be a good topic to share with others:


Hi Allen,

Last time I emailed you, I was 80% complete in a few months, I’m getting a little closer now.

I’m working on the fan, Sheet #35. Because there are no assembly drawings on many of the subassemblies, it makes things interesting, like a puzzle. The fan hub takes a .156 x .312 flanged support bearing for the Fan Shaft. But where does the other bearing go. (a shaft needs two support bearings). I assume it goes in the Fan Belt pulley. But in you kit of bearings there is no bearing that size.

As always thank for your help.


From South Florida: Weather report for today - 81 degrees


Hello Ernie,

Hey - no fair bragging about your weather!

After some study and speaking as an amateur, here's what it looks like to me:

1. Insert a .156 ID x .312 OD x .125 flanged bearing, flanged side out, all the way onto the Fan Shaft.
2. Insert the Fan Hub into onto the Fan Shaft, narrow end attached to the bearing from step 1.
3. Insert the second .156 ID x .312 x .125 flanged bearing on the Fan Shaft, flanged side out.
4. Insert the Fan Belt Pulley onto the narrow end of the Fan Hub.
5. Attach the Fan Mounting Bracket on the remaining exposed end of the Fan Shaft.

See if that makes sense to you.




That cleared it up.  In summary there is a ball bearing inserted on each end of the Fan Hub. But, why is there a .500 dia x .190 dp cut out in the Fan Belt pulley. I think it would have made more sense to put the other ball bearing in the Fan Belt Pulley. 

One more thing, the gears. Cutting gears is expensive due to the cost of the gear cutters and a rotary table. The gears can be purchased from SDP or other gear houses, expensive. However, I purchased then on eBay for about $3.00/gear. Only slight modification is needed. If you would like more info just ask me. You may want to pass it off to others.

I certainly appreciate the help, thank you again.



Yeah, I wondered about that deep cut on the Fan Belt Pully.  I can only guess that Dad did not think it needed all of that bearing surface contact, and also makes it easier to disassemble should the need arise.  He knew he would have to disassemble the engine after he built it to draw up the plans (contrary to typical product development, Dad built his engines first, then developed the plans after!)

Send some of that sunshine and warm air up here.  We could use it!


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