In a message dated 8/8/2006 5:03:24 P.M. Eastern Daylight Time,=20 ALVentures@cox.net writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#0000ff size= =3D2>

My limited=20 understanding was/is that the fear in high oil temps was permanent set in=20= the=20 side seals. Didn't get the pan oil temp for the lack of =E2=80=98pag= ing=E2=80=99 of the=20 monitor screen. The oil pressure was about 85 psi. What sort of alloy of=20 indium is used on the bearings?

= You can=20 reduce oil temps by limiting throttle settings. A slight reduction can mak= e a=20 big difference. Also reduced ignition advance and richer mixture settings=20 help.

The mixture d= uring=20 full power climb was lean =E2=80=93 O₂ sensor at the bottom of=20= the=20 scale. The pilot didn=E2=80=99t recognize the need to tweak the mixt= ure knob,=20 and the MAP was a bit higher (~1=E2=80=9D hg) then I had ever seen on stat= ic due to=20 the dynamic pressure of the ram induction scoop.

I have never seen a side seal fail due to anything. They do get=20 damaged during other misadventures. Alloys of lead and indium and maybe alum= inum=20 are all used by various MFRs

for the top layer of their bearings. Racers use the race bearings with=20 .0005" extra clearance or machine away the overlay and run on the copper=20 substrate. The overlay is just under .001" thick so the extra clearance is j= ust=20 right. Copper is a very strong bearing material, but less forgiving of dirt=20 particles than the indium.

A more typical take off power setting would be full rich. A Continental= =20 O550 might use 32 GPH for take off and then cruise lean of peak at 13 GPH or= =20 even less. The cylinder head temps must be seen to be believed. Properly=20 operated engines, even those "piston ones"

can actually go to overhaul with the original cylinder still on=20 them.

Just going richer might be enough to get the oil temps under control. I= f=20 the high temps are just from take off and climb, then a water spray on the o= il=20 cooler might work just fine.

Running a little bit lean of peak EGT will not hurt anything but will r= aise=20 operating temps. Both oil and water.

Cruise should be more lean yet so that the percent of full power i= s a=20 function of fuel consumption. The rotary will run almost 200 degrees lean of= =20 peak EGT, and how close is a function of the ignition system performance and= =20 plug gap. Of course the amount of power is also way down along with fuel=20 consumption. Mixtures well lean of peak are also very cool running for water= and=20 oil temps. Simple, Less heat from less fuel =3D less heat.

Lynn E. Hanover

-------------------------------1155086645--