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Date: Mon, 21 Mar 2005 19:16:50 -0600
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Under driven waterpump pulley
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<... The reason that the water pump pulley in question is 5 inches in 
diameter is that with the reduced diameter "Racing Beat" eccentric shaft 
pulley that most of us use it is impossible use a larger pulley on the 
water pump ....
I'm lost here ... what makes it "impossible"?  Pulley interference?  Not 
enough belt contact on E-shaft pulley? 
I'll have to take a closer look at my water pump ... Jim S.


Kelly Troyer wrote:

> Jim,
>    Looking into warerpump impeller design is way past my desire or 
> ability........I am sure
> that with enough  time and money a more efficient pump can be 
> had......That being said
> I want to get into the air in this lifetime and chose to use the stock 
> pump which has been
> proven by Tracy and many others........It has also been documented by 
> several that the
> stock pump is on the edge of cavitation between 6500-7000 engine 
> rpm........For that
> reason I think it would be prudent to underdrive the pump for those of 
> us using the
> RD1C 2.85 redrive........Tracy, Ed and others are already closing in 
> on 7000 rpm in cruise
> if they choose........Tracy runs well over 7000 rpm when 
> racing........The reason that the
> warerpump pulley in question is 5 inches in diameter is that with the 
> reduced diameter
> "Racing Beat" eccentric shaft pulley that most of us use it is 
> impossible use a larger
> pulley on the waterpump....... IMHO
> --
> Kelly Troyer
> Dyke Delta/13B/RD1C/EC2
>
>
>
>
>     -------------- Original message from Jim Sower
>     <canarder@frontiernet.net>: --------------
>
>
>     > Kelly and all,
>     > I might have missed this too, but do you know if anyone (like the
>     > racers) has looked into impeller design of EDWP and come up with
>     > something that operates better in our envelope? The turbine looking
>     > design of the EWP suggests that a unit like that /hugely/
>     underdriven
>     > would be much more optimal for our purposes. But unless it was
>     really
>     > popular, would probably be hugely expensive. As for your
>     pulleys, 5"
>     > doesn't sound like a lot to me. A pump that works in stop-and-go
>     > traffic with the AC on and engine at idle (< 1000 rpm) seems
>     like it
>     > would work OK at 7500 rpm with about a 8" pulley, unless you're
>     planning
>     > on going with a smaller drive pulley to underdrive the
>     alternator too.
>     >
>     > I'm currently looking at a 13B with RD1C operating at 7500 rpm
>     cruise
>     > and capable of 8000 or so if I get in that big a rush. Stock
>     pulleys
>     > wouldn't do at all for that application I'd think. I need about
>     210 hp
>     > for what I aim to do, and extrapolating 160 hp linearly from
>     6000 rpm
>     > barely gets me there. Anyway, I need to start keeping better
>     track of
>     > happenings on this list.
>     >
>     > Sorry to be doing all this catching up "on company time" ... Jim S.
>     >
>     >
>