From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of sqpilot@bellsouth.net
Sent: Wednesday, May 11, 2005 3:28 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] sq2000 cooling success !

Hi, fellow rotary enthusiasts....I just had to share my rotary cooling success story. As many of you know, I have an SQ2000 canard with a belly mounted NACA duct.  I decided to try adding VG's in front of the NACA duct, as several other canardians suggested. Here is a link showing the VG's and oil flow test. http://users.telenet.be/westlandfamily/cozy/vg/index.htm

I conducted two flights today, one without the VG's, then one with them added.  OAT was 85 degrees, and very humid. (We were sweating just standing around).

    On flight one (prior to addition of VG's), climb temps hit 210 (water temp) and stabilized at 205 at WOT. The highest oil temp during the flight was 190.

    I landed, and we riveted on the two aluminum VG's and I took off again.  Water temp during the climb maxed out at 190, and took much longer to reach those numbers. I raised the nose to climb at 90 IAS (which I have not done previously) and water temp rose to 195. I lowered the nose to climb at 100 IAS and the temps came back down to 190. After leveling off, water temp was 180 at WOT.  At approximately 3/4 throttle (cruise) water temp was stable at 172 at 3000 AGL. After throttling back for descent, water temps stabilized at 160 where they remained until landing rollout. During taxi back to the hangar, temps rose back up to 182. Highest oil temp during this flight (at any configuration) was 182.

     It seems obvious that the VG's had a positive influence on the cooling efficiency.  I don't profess to understanding exactly how the VG's trip the air into the NACA duct, or being an expert on VG's or cooling issues. I am only reporting what worked for me. The addition of the VG's changed my marginal cooling system into a success story.

     I should also mention that I did not raise the front nosewheel, as I wanted to see how it would cool in the worst possible situation, (ie landing gear motor unable to regtract the gear) and slow climb speeds.  I suspect that on the next flight, when I retract the nosewheel and attain a higher airspeed (at the same power settings), my temps might even come down a couple more degrees.  I still need to add wheel pants and clean up the airframe and paint it, but I have finally attained a cooling system I am very pleased with.  Paul Conner, smiling in Mobile, AL