A common issue with Cardinals, especially Cardinal RG's, is keeping them cool in climb on hot days. Most RG's take a little effort on those over-100 degree days, at least until you can nurse them up to altitude.
Tony Williams wrote up a list of options for the CFO Digest, and that report is presented here along with links to the various web pages that address these many suggestions.
Thanks, Tony, for putting it all in writing! Keith Peterson, Webmaster.
I could offer the following suggestions:
1. Keep the air speed up in the climb. 90 mph / 105 knots if you can. Sadly, you're going to be in the heat for a longer period of time. I use a "dipsy doodle" maneuver, where when the temp starts getting uncomfortable, I push the nose over and let the speed build up (don't descend however, 'cuz we wanna climb eventually into the cooler air), and the temps should come down a little. Climb some more... level off... Get as much air going through the cowl as possible, as long as possible. Just keep thinking how nice it'll be when you finally get up to 10,000 feet. {Check out Vince's oil temp data for the facts on this. KP}
2. As you've probably seen suggested by others, get the 172 (larger) oil cooler. Spend money on that (and sell your present cooler) rather than spending money on "A&P guessing games" with the oil temperature regulator. That doesn't mean you can't test it with a can of heated oil and a simple drug store thermometer.
3. Make sure air is getting over the oil cooler.
seal up the gaps between the oil cooler and the air
duct assembly placed over the top of it. Steve
Conners used to sell a kit, consisting of small pieces of
aluminum, that did that. Some
silicone baffling material strategically placed will do
the same. On the FG, make sure the SCAT hose (supplying air to the oil
cooler) doesn't have any holes. On the RG, make sure the NACA scoop
baffle seal material is on the outside of the
duct.4. Eight quarts of oil will just make a mess on the belly, and while it may take an extra 60 seconds to warm up, I'd stick with the 6 to 6.5 quarts of oil that most of us use. There are lots of holes around the engine baffling that you can plug with RTV sealer. You can buy this stuff in any auto parts store.
Of course, check the baffles. A whole roll of that material, in red silicone, is about $30 bucks form Sacramento Sky Ranch, Chief, or Aircraft Spruce. Get some aluminum pop rivets, rivet gun, and big aluminum washers (Sears has 'em) and replace the baffles now. {you might also consider aluminum strips KP} Be sure and plug any small holes in the center of the pop rivets! Look at the huge gap around the alternator... I'll bet some silicone baffle material can accidentally get in there, too. {or check out another way this was addressed. KP}
5. Look at the cowl flaps and fire wall of a Cessna Turbo 210, and imagine the cooling needs of this 285 horsepower machine ! Some models have a curved lip at the bottom of the firewall just above the cowl flap opening. Smooths that transition of air going out the bottom of the plane, and a mod like this has been experimented with on some Cardinals. Perhaps somebody can post what effects, if any, this achieved.
6. I'm told that it a pinch, some folks have resorted to a simple "water cooler". A windshield washer type tank and pump (junk yard for cheap) and a piece of hose and windshield squirter nozzle placed just above the oil cooler. One gallon or so of FAA certified water should provide a continuous spray of water over the oil cooler until you can reach cooler air. You'd be amazed at the effectiveness of this simple (illegal) mod.
7. For fuel injected engines... some have advocated cruise climbs at a mixture that is lean of the peak exhaust gas temperatures by 25 to 100 degrees. While the climb power will be reduced somewhat, cylinder temperatures will be noticeably less. This is a subject, sadly, that is fraught with religious zeal, both pro and con, so act responsibly.
For carbureted and injected planes, try running 125 - 150 rich of peak in the climb out. {I would suggest running as much fuel through as required to cool the engine, after you've run out of other tricks. It's cheaper than a new engine! KP}
8. Add the aftermarket exhaust fairing. Not as a "speed mod", but as a cooling mod. This should allow a slightly higher pressure differential between the top of the cylinders and the lower cowling. Vince E. told me that the "shark gills" on the side of the cowling of the turbocharged airplanes actually does improve cooling (heck, I just thought they were for show :-)
9. Move to Alaska, fly late at night / early am only :-)
Tony Williams * 1970 FG * N177AW * San Diego MYF