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Date: Sun, 20 Sep 2009 12:50:41 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] VG aiding : [FlyRotary] Re: Another mixed day / Cooling
 experiments
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If I understand it correctly, the 'bluff body', detailed in the CAFE 
articles I referred to earlier, does essentially the same thing; the 
bump accelerates the airflow & it (the bluff body) is sheared near the 
point of highest air speed. That creates a low pressure area for the 
cowl air to exit into.

I still think that if the tortured path of the air after it leaves the 
heat exchanger is straightened & cleaned up, that would make a lot more 
difference. (exit duct on the *side* of the cowl, exiting into the low 
pressure area near/above the wing's leading edge??)

Ed Anderson wrote:
>
> IF the VGs are generating a vortex and are placed the right distance 
> apart, closely spaced spinning vortex of air mass may act as an 
> extension of a cowl flap area by preventing/hindering the higher 
> pressure/velocity external flow from equalizing the pressure as soon.
>
>  
>
> Just an opinion (and that is about all it is)  about why a set of VG 
> MIGHT give some benefit.
>
>  
>
> Ed
>
>  
>
> Ed Anderson
>
> Rv-6A N494BW Rotary Powered
>
> Matthews, NC
>
> eanderson@carolina.rr.com
>
> http://www.andersonee.com
>
> http://www.dmack.net/mazda/index.html
>
> http://www.flyrotary.com/
>
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW 
> <http://members.cox.net/rogersda/rotary/configs.htm>
>
> http://www.rotaryaviation.com/Rotorhead%20Truth.htm
>
> ------------------------------------------------------------------------
>
> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] 
> *On Behalf Of *Mike Wills
> *Sent:* Sunday, September 20, 2009 12:01 PM
> *To:* Rotary motors in aircraft
> *Subject:* [FlyRotary] Re: Another mixed day / Cooling experiments
>
>  
>
> I'm with you on the VGs. If your cowl flap didnt create enough 
> negative pressure to acheive the desired results I dont see VGs being 
> more effective. I dont recall ever seeing VGs used on any sort of 
> factory built airplane for this sort of problem and I'd think if it 
> were that simple the manufacturers would be doing it.
>
>  
>
> Mike Wills
>
> RV-4 N144MW 
>
>     ----- Original Message -----
>
>     *From:* Tracy Crook <mailto:tracy@rotaryaviation.com>
>
>     *To:* Rotary motors in aircraft <mailto:flyrotary@lancaironline.net>
>
>     *Sent:* Sunday, September 20, 2009 6:03 AM
>
>     *Subject:* [FlyRotary] Re: Another mixed day / Cooling experiments
>
>      
>
>     "It IS seeping from the filter seal and NOT the two hose
>     connections...no doubt on this. "
>
>     Just from observing many rotary installation 'de-bugings' over the
>     years (including my own) I noticed that difficult to solve
>     problems are almost always caused by false assumptions.
>
>     It is possible to get several bad filters or two bad filter mounts
>     but the mathematical  odds are staggeringly small.  You haven't
>     offered your test proofs as to why you know they are bad and
>     leaking but if I were betting, I'd put my money on something
>     else.  The assumptions about the wiring might need examination as
>     well.
>
>     This reminds me of an oil leak the Ed Anderson had.  The oil was
>     showing up on the back side of one of his rads.  There was an oil
>     line running very close (< 1" as I recall) to the rad so the
>     assumption was made that the oil line was leaking.  Long story
>     short, the oil leak was actually coming from something at the
>     opposite end of the engine.  What exactly was it Ed?  It defied
>     all logic in that it was not even close to where it showed up and
>     the oil was traveling against the assumed airflow under the cowl.  
>
>     Speaking of assumed airflow, my cooling experiments are blowing
>     away all my own assumptions.   I kluged up the cowl flap I
>     mentioned and fixed it in the open position.  The trailing edge of
>     outlet is about 1 1/2 " below  where it was.  The temperatures
>     were down a little but not near what I wanted.  Only a little
>     better than the big giant opening I tried.  At this point I was
>     ready to conclude that the underside of the airplane was bad place
>     to put a cooling outlet.  Keep in mind that my working assumption
>     is that the pressure under the cowl is too high to allow good
>     airflow through radiator and oil cooler.  I had installed a
>     pressure probe under the cowl but forgot to look at the reading.  
>     Figuring I might as well know how big a problem I had, I made
>     another flight to check the under cowl pressure.  Duhh,  almost
>     nothing!  Checked the probe to make sure it was not blocked,
>     pinched, etc, and everything looked OK.   I need to check pressure
>     in a few other spots to be sure about this.  There is something
>     odd going on with airflow under the cowl but I'm back ti head
>     scratching mode again.
>
>     One builder on the RV list said he got a big improvement in
>     cooling by installing VGs on the trailing edge of the cooling
>     outlet.  This is so non-intuitive that I can't imagine why it
>     would work but its so easy to try I might have to do it while
>     scratching my head.
>
>     Tracy
>     .
>
>
>     On Sun, Sep 20, 2009 at 1:37 AM, Chris Barber
>     <cbarber@bellairepolice.com <mailto:cbarber@bellairepolice.com>>
>     wrote:
>
>     Made it out to the hangar for most the day and decided to take the
>     advice here and modify my start up routine based on what was
>     suggested here and in the manual.  So, I cranked the mixture full
>     rich with no priming and it started up in a few blades.  Ran for a
>     while, shut down and started back up with mixture in about the
>     2:00 oclock position....and it started fine.  Kewl.
>
>      
>
>     The first bad news is that I replaced my romote oil filter mount
>     and installed a new filter.  As I have mentioned here I have had
>     it leaking at the rubber filter seal.  The old one looked ok, but
>     since replacing the filters no less than three times and knowing
>     that the eye cannot see all inperfections, I replaced the mount
>     AND filter (K&N 2004 filter).  But, NO JOY. It is still leaking
>     where the filter mounts.  It IS seeping from the filter seal and
>     NOT the two hose connections...no doubt on this.  I know the
>     rotary's oil pressure is higher than other engines but I would not
>     think it would be so much that it is overwhelming this standard
>     mount and seal.  This is just a standard screw on remote oil mount
>     made out of AL...Made in the USA.  Looks like many others I have
>     seen.  Y'all have any ideas. 
>
>      
>
>     Second good thing is a guy from a few hangars down turns out to be
>     a welder by trade.  He came down as I was working on the new
>     stainless turbo exhaust manifold the other day after offering to
>     help me modify my manifold..  As was mentioned here before, the
>     old cast iron manifold I had wold work if mounted upside down.  It
>     puts the turbo lower (the oil return being about 2 inches higher
>     than the oil inlet return in the pan) to the rear of the engine
>     and it clears my aileron control link.  I will have to make a very
>     small modification to the lower cowl to give me proper clearance
>     EXCEPT the wastegate interfeared with the Mistral intake fuel
>     rail.  So, I ordered a stainless copy of the cast iron one I had,
>     based on John Slades suggestion.  My welder friend said it would
>     not be too big a job to turn the wastgate extension around which
>     should allow it to miss the fuel rail completly.  We looked at the
>     options and he took the manifold with him saying he would cut off
>     the old wastgate extention and come back to fit the new part on in
>     a few days. Kewl.
>
>      
>
>     The second bad news is that I was doing some continued tuning.  I
>     even transferred A to B as B was a bit rough from the factory and
>     it worked fine.  HOWEVER, later in the day, after feeling pretty
>     good about the lasted progress (excepting the continued leak) the
>     engine stopped. Huh?  It will not restart.  I checke the first
>     fuel filter and it is clear.  I decided to start at the beginning
>     and just run the EC2's diagnostice test.  Damn, no chattering of
>     the injectors (even though I was able to hear an individual click
>     when I primed it).  Put on a test plug and wire and got no spark. 
>     All the other electrics are working fine.
>
>      
>
>     I pulled my extra EC2 out and installed it and I got injector
>     clattering away and spark on three of the inectors.  The secondary
>     on Rotor one did not seem to fire.  Hmmmmm?  I put on an extra
>     injector that I had and tried again, and it didn't fire...then
>     fired for a few seconds and then stopped. Looks like I have some
>     more wire issues.  Damn, I though I had really gotten past most of
>     those.
>
>      
>
>     I am really confused about the EC2 seeming to just shut down.  The
>     other electrical componants are all working, but the EC2
>     componants are not.  Strange since I thought each items (injectors
>     and coils) had there own power source thus should not shut down as
>     a "team" like this.  Yes, it is the same on A and B.  Currently I
>     am very discouraged so I stopped for the night and decided to
>     crawl into bed with a hot blond and sulk (she was actually
>     gracious enough to hang out in the hangar with me for a few
>     hours...whata gal)....well, she helps me from sulking too
>     much.....this dating in my 40's ain't all that bad <g>
>
>      
>
>     I anxiously wait commentary and possible explanations from y'all. 
>     Upon my return to the hangar (today was MY Sunday) hopefully
>     tomorrow night after work I will be looking at my, apparntly piss
>     poor, wiring.
>
>      
>
>     As always my friends, Thanks.
>
>      
>
>     All the best,
>
>      
>
>     Chris Barber
>
>     Houston
>
>
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