----- Original Message -----
Sent: Sunday, November 07, 2004 7:09
PM
Subject: [FlyRotary] Re: EWP
Rusty I don't see, how more
cooling flow at low rpm will cool better, there is still no change in
radiator-size/airflow/etc.
It's pretty well established that more flow equals
better cooling. I'm not qualified to explain it, but plenty of
people here are, and you can probably find ton's of info in the
archives.
I believe that's where people are wrong: Most car
radiators are way to big for the average driving, so increased cooling flow
will reduce overheating at to low a speed. But in your aircraft you will have
the radiator sized to the minimum possible to reduce drag. Just because you
pump the water more often through the radiator (that what it comes down to
when you say more flow...) it will still not cool better if the radiator
cannot get rid of the heat. I think to improve this the only way to go is to
improve the radiator airflow. Your radiator should be big enough to handle
continous max power at minimum indicated airspeed and AOA. If you have
overheating problems at idle at taxi speeds, more flow in the system will
solve the problem without increasing the airflow through the
radiator.........
no cavitation at high rpm: use
underdrive pulleys
And make the low rpm overheating
worse.
see above...
and maintain the belts in correct
alignmentand tension and you will never loose one..........:)
I'd be more or less willing to agree with this.
If I had a factory set of pulleys, accessory mounts, and adjustment arms,
I wouldn't be as worried. Unfortunately, many of us are forced to
make our own accessory mounts. I've even had to use a pulley
that needed to be modified to fit the shaft on my alternator.
The chances of a failure with these added variables is far more likely than
stock, and as I mentioned, broken or thrown belts have stranded
me on two occasions, both in factory
applications.
(I have abour 5000 hrs flying time in
front of belts double-v-typ as the only means of powertransfer from the engine
to the rotor....)
How much do you think Robinson spent developing
that v-belt drive? It had better work
:-)
Exactly! Now why would I not want to copy him?
Use a double-v-arrangement withat least double the
capacity needed with a constant tension idler pulley and you should never have
any problems.
Cheers,
Rusty (I hate belts, and they hate
me)
DOn't get me wrong, I know there a a lot of factory pumps
that are a disgrace to pumps in general and should be called
junk!
What I say is the concept to use a waterpump with belt
drive is about as simple as it goes. Change for a good aftermarketpump, a good
set of pulleys adjusted for your rpm needs, align them as good as possible,
use aquality belt, a springloaded idler and you are done.
Somewhere in another post on this newsletter, same
thread, someone said that I am wrong concerning the need for a bigger battery
wit a EWP.
Well you don't need a bigger battery unless you would
like to keep your sparetime to engine shutdown the same as without the EWP.
You also will need a bigger alternator...about 4 to 7 amps bigger, according
to the numbers showing up on the list :)
Thomas J.