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Date: Sat, 30 Apr 2005 12:45:00 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: best climb, was: warp drive 3-blade prop
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Ed Anderson wrote:

> Hi Bill,
>  
> Great to hear from you.  Excellent write-up on your cooling endeavors 
> - bound to assist others with theirs.  I am thinking about a major mod 
> to my cowling including a flap so thanks for sharing.  
>  
>  Are you going to make Charlie's Flyin?  I intend to present some 
> findings from my continued studying of the cooling challenge that may 
> be eye opening.  It turns out my 28 sq. inch opening total for the two 
> cores is working (but is the lower limit in my opinion) but not for 
> the reasons I initially thought.  It turns out Good pressure recovery 
> is both a blessing and curse to good cooling.  How's that for a teaser?
>  
> I initially attempted to climbout at 91 mph (or what ever it was that 
> Van say was best rate of climb) - then I found out all his performance 
> figures were for CS props.  I found out by experimenting that my best 
> rate of climb (at that time) was 120 MPH IAS - which was exactly what 
> Tracy said he had found.  Better rate of climb speed (for a fixed 
> pitch prop) and of course more cooling air that with the nose stuck up 
> and the airspeed/airflow slow at 90 MPH.
>  
> Disappointed I could not make it to Sun & Fun  - it was that tailwind 
> I'm certain.  But, engine is rebuilt and it appears much stronger than 
> the old engine even right after I had rebuilt it.  When I first took a 
> compression check in the shop cranking it with a starter I was a bit 
> disappointed in that I was only getting 95 psi - but then I found the 
> engine was so tight that it was tough to get started - in fact, I 
> could not get it to idle below 2200 rpm the first day.  I initially 
> thought I had fuel system problems because the fuel Map just wasn't 
> working out.  I had to jump the battery with the car to get enough rpm 
> and voltage to fire the engine.
>  
> I'm happy to say as the engine has loosened up over about 3 hours of 
> run time, it will idle at 1600 rpm (not as well as I would like - but 
> idles) and does fine at anything above that.  Quick blips have had the 
> engine up to 6000 rpm static (2.85 gear box) and experience has shown 
> as the engine sets in performance should improve over the next 20-50 
> hours.  The exhaust note is deeper and with a sharper bark - may be 
> the result of better sealing.
>  
> Anyhow, hope I see you at Charlies
>  
> Best Regards
>  
> Ed

For you RV flyers, Van 'his own self' wrote an article about it years 
ago & said that due to the wing planform RV's climb just as well at 120 
as 90 so just cover ground while you climb & cool better in the bargain. 
That was obviously with Lyc power. IIRC, it was due to the drag going up 
rapidly at the higher angle of attack when trying to climb at lower 
airspeed.

Charlie