Mailing List flyrotary@lancaironline.net Message #14939
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: fluidyne oil cooler
Date: Thu, 6 Jan 2005 18:09:46 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
Depends on how much HP you make???  If you make the 180 - 195 that I think you are making I don't think this cooler will work due to the added thickness you mentioned.   
 
I'll be really interested to hear Tracy's take on this.  I think he's going to be disappointed when he hears the actual dimensions, at least for his 20B application.   While I'm still sure it would be safe to fly, I'm not quite sure it will be everything I want it to be.   Kinda thinking about exchanging it for the next larger version.  
 
I did some estimation of the core size of the next larger version, the 30617.  It's listed as 14.75 x 9.25 x 3, but I'm estimating the core to be 11.625 x 9.25 x 2.25 based on the construction of the smaller cooler.  That gives a volume of 242 cu in (vs 165 for the smaller one), which seems far more likely to succeed.  Unfortunately, the larger size will mean that it won't fit as well, and won't have nearly as nice of a ducting scheme.  Fortunately, Summit has a very good return policy, so I just ordered the next size for comparison.  I'll probably end up  keeping the larger one, since I can't take the chance of ending up with oil temp problems again.  I'm also not ruling out abnormal aspiration to get more power in the future, so more cooling is better.    
 
 If you choose to try it anyway because of the good installation location (which seems like a pretty good tradeoff) you could use a C&R oil-to-water cooler as a 'fall-back plan' to get the additional oil cooling you need since your water temps are good and you have excess water cooling.  I have a 84 mazda water-to-oil cooler I'll loan you want to try it but I'm not to hopeful for this cooler to help.
 
Thanks for the cooler offer, but I'll pass.  I just finally looked through enough parts manuals to figure out that the oil/water cooler wasn't used on the 13B, so it was only (marginally) semi-capable of working with about 105 HP.   Doesn't sound promising, even for a single rotor.  
 
As for oil/water heat exchangers in general, I like the idea.  I even briefly considered replacing my bad oil cooler with another evap core being used for water, then try to find a place for an oil/water heat exchanger.  I'm afraid 4 cooling devices trips my limit though, so I think I'm stuck with a normal air/oil cooler for the RV-3.  The RV-8 would definitely get a single radiator, and an oil/water exchanger. 
 
For the single, I'm going to have to sump mount the engine, without much room for a pan.  I'm considering making a dry sump system out of it, with an oil/water heat exchanger doubling as an oil reservoir.  No firm plans yet, just random thoughts.  
 
Cheers,
Rusty  
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