Hangar Flying

Glennbob,
Glad you mentioned the vac pump---I was cooling that too.

For my Longez, the original large naca scoop was used for oil cooling, carb ram air, and accessory cooling.  The downdraft scoops were not naca scoops.

On my Cozy, I am considering using a small naca scoop for oil cooling.  If I go this route, I would buy the scoop.

Charles,
Your pix look great!  I'll be very interested in how it cools.  I built ram scoops (non-naca) because I was afraid that there may be some separation off the top of the strake---and that there may not be enough air actually going in them.  Nacas on the bottom or sides of the plane are much easier to feed.  Not many people were building downdraft cooling when I did mine---so I made sure that the scoops were well into the airstream.  Terry S (naca) has had trouble with his---but Bill James has not.  George Shell and myself had no issues either.  

And I am sure that you have found that the greatest thing about downdraft cooling is not having to baffle around all the crap on the back of the engine (starter, alternator, oil cooler, etc).  Cool!!   Sorry, couldn't help that one.  

I did downdraft cooling and for simplicity, sealed off the lower NACA scoop.  I put 3 SCAT flanged connectors on the sealed off naca wall and built 1 rectangular flanged aluminum connector.  The biggest SCAT connector (3in?) went to an oil cooler box that I built that mounted behind the carb.  The 2 smaller connectors went to go cool other stuff.  I built a fiberglass extension on the hal hunt ram box to fit over the rectangular flange slip joint.  Don't have any other pictures that is not already posted on my web page.

I'm in the process of moving---so don't have access to my binders to confirm the articles.  However here is a list worth looking at (all Central States articles):
issue         page         subject      title
58   20   engine   downdraft cooling
63   14   engine   downdraft cooling
63   23   engine   downdraft cooling
63   32   engine   super augmented eze cooling
65   20   engine   design for optimum cooling efficiency
67   7   engine   naca diffuser
74   17   engine   Downdraft Cooling Experience
76   10   engine   Engine Cooling Design
76   12   engine   Engine Cooling

My guess is that it is issue 65.  The one that I am thinking of talks about how much to close off the top and bottom intercylinder baffles.  If I remember right it was based off of a CSA member researching some NASA (or maybe NACA) files talking about cooling air-cooled engines.

I assume that you are now using CHT probes that attach to the CHT boss---and that they are the ones the Engine Monitor manufacturer recommends.

470 is way too hot for cruise.  You did not say how hot the other ones were.  If the other ones are way too cold, then it is a simple matter of stealing some flow from the way too cool ones and redirecting to the way too hot one.  If you can't spare trading some heat (raising the temps of the others to bring down the hot one), then you probably have a lot of air leaks.

Assuming that you have a standard size NACA inlet duct and a fairly normal exit opening, you may have problems with your baffles.  You need to make sure everything seals.  Look around the cylinders--all the air should channel thru the fins.  If the metal baffles are pulling away, then you need to fix it.  There is a lot of reading material that shows how much of the cylinder needs to be covered (entrance and exit openings).  Wait until after dark to look at the baffle sealing.  Put a light under the cowl and look for light leaks---fix all those problems.  Do it with both cowls on----and then one at a time.  Check around the alternator and starter (and of course if you have downdraft, you don't have to check around the alternator and starter----     )

Also pay attention to any wiring, ducting, etc that you have running underneath the cylinders.  If you have a lot of junk in the way, air is going to have a hard time making it through any rats nest you may have down there.

I think that it may be pretty difficult to go lean of peak without fuel injection.  And even with fuel injection, I think you have to tune the injecters to get them all to peak at just about the same time...At least that is what I have heard.

With high compression pistons, you just have to be a little more careful with leaning.  The higher force with the higher compression-----mixed with lots of heat from aggressive leaning (leaning towards peak temps)----and mixed with being at 75% or greater----can be a bad combination.

Under normal conditions, don't aggressively lean until below 75%.  With high compressions pistons----be a little more careful.  Don't know that I can tell you what a little more careful is.  If there is a rule of thumb, I'd like to know too.

You can get vortex generators from these guys pretty cheap.

http://abianconi.hypermart.net/Vortex.htm

When I bought them for my Longez, they came with a template and instructions as to where to put them.

These are for a GU canard---not a Ronz canard

I had to go back to my webpage to see what you were talking about.  If you look at the right hand picture (upper cowl off, lower cowl on, looking directly from the rear), you will see the bottom edge of the rear baffle---it is a straight edge that passes above all the pipes.  Other than the curvy pieces that wrap around the cylinders, there is nothing else below that line.  It is all open space.  This is why downdraft is so easy to baffle.

I need to update my webpage with all my Cozy stuff.  The Longez was sold well over a year ago to a Navy Doc in Biloxi.  Not that long afterward, Katrina hit.  The airplane was in a large hangar at Stennis Airport.  The hangar flooded with salt water, the airplane floated, and when the water receded, it came to rest on its tail.  Insurance company totalled it.

It had a very powerful O320 on it with very little hours.  Unlike my Cozy, it did not have electronic ignition and fuel injection.