Mailing List flyrotary@lancaironline.net Message #12718
From: rijakits <rijakits@cwpanama.net>
Subject: Re: [FlyRotary] Re: EWP
Date: Mon, 8 Nov 2004 19:11:35 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Let's go green :)!!
----- 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.
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