Mags at Altitude
 

I can remember reading about the P models, who have pressurized mags. If they get to some altitude, they have to have pressurized mags to avoid, something. Mis fires. Those of us with normally aspirated Skymasters, if we get up high, what prevents those mis-fires? Can we get pressurized mags? What do the Turbo Skymasters use? I got my O2 system all set to go, and I want to get up to some altitude and catch the tail winds.:D
Thanks

LARRY, NO PROBLEMS. HOW HIGH DO WANT TO GO? I'VE HAD MINE BEYOND SERVICE CEILING BEFORE. I AM NOT SUGGESTING THAT YOU SHOULD DO THIS BUT WHEN FLYING THE WESTERN PART OF THE STATES YOU NEED A LITTLE MORE ALTITUDE THAN OUT HERE IN THE FLAT LANDS. IT'S BEEN REALLY A PLEASURE FLYING OUT HERE BUT I HAVE NOT BEEN ABOVE 9000 BUT MAYBE TWICE. I USED TO FLY 10,000 TO 14,000 ON A REGULAR BASIS. SKYMASTERS DO JUST FINE. USUALLY SEE 16 OR 17 INCHES MP AND 23-2400 RPMS. NO PROBLEM, 4 PASSENGERS AND LUGGAGE WITH FULL FUEL. SEVERAL TRIPS TO ALASKA WITH EVERYTHING YOU FIT INTO IT AND AWAY YOU GO. THE ONLY NAVAGATION WAS ADF (BEFORE LORAN) WE WOULD HAVE TO FLY THE TRENCH. 250 MILES OF NOTHING BUT WILDERNESS. NO RUNWAYS, NO VORS, NOTHING FOR NAVIGATION EXCEPT A SMALL RIVER THAT TURNS INTO A HUGE RESIVOR. ANYWAY, MANY TIMES AT 10-12,000 WITH MAX LOADS. I ALWAYS THOUGHT TURBOS WOULD BE NICE BUT NEVER HAD THEM ON A SKYMASTER. ALTHOUGH I DID FLY WITH DAD IN HIS 320 SEVERAL TIMES AT ALTITUDES ABOVE 25,000 AND THAT WAS NICE GOING EAST WITH 100 KNOT TAILWINDS.

YOUR AIRPLANE WILL HANDLE FINE AT 12-14,000. LET'S GO TRY IT AND GET SOME BREAK IN TIME ON THAT NEW ENGINE.

Larry,

Not all P337s or T337s have pressurized mags. Rileys all do, but other than that, I would say most do not. If you do proper magneto maintenance at every annual, you don't need pressurized mags, although I think they are a good idea.

The source of the pressurization is the turbo, so on your bird, you can't get pressurized mags anyway.

I flew my '65 337 as high as 16,000 feet without a problem.

Rock on.

Kevin

Great, Thanks
It (the new engine) has finally entered production, (9 weeks after we ordered it) so in just a few weeks I should be able to do that. I think the first few flights have to be down low, 75% power. Then we can go high.

high
 

Larry, Why do you think you must stay low with a new engine? The object of operating at 75 percent power for a number of hours is to keep the engine warm as rings seat into cylinders. Go high and enjoy it.
Jerry

Oh-oh! We have a new engine on order. Not expecting it to take that long. Ordered from Air Power. Please tell me they are not taking nine weeks! (IO-360C)

new engine
 

Hi Jim, Sounds like you were down the same road with them? See ya in Florida.
Jerry

We ordered ours on Dec 12. I was informed on Feb 10 that it was ready to start production. Getting ready, not actually started, mind you. In a couple of weeks, it will be done. Sounds like a long time to me. It's okay, my mech has been doing other things, with other peoples airplanes. Gives me time to get more engine reserve saved up:D

Re: high
 

I think, no book in front of me, and quite frankly, I'm not certin I could read it at this our, but I think that to get 75%, I have to be at 5K, or lower, for normally aspirparated engine.

Larry, I think you are right. Break it in down low first where you are certain of 75% power. The rings will seat a lot better. I've had constant problems with high oil consumption on my rear engine (525 hrs SMOH) versus the front (1075 SMOH.) My engine guru attributes it to poor ring seating when the engine was right out of overhaul (before I got it.)

On flying high, I go to Colorado in the summer and have often topped 14K to 16K VFR on hot days. I've had a light load, generally 10%+ under gross weight. I use a portable O2 system. I fly home from Eagle (EGE) to MEM at 11K (don't use O2 here) non-stop (900 n mi +/-) 5:45 to 6:15 with 1:30+ in reserve fuel. That's about 17-18 gph at 2400 RPM.

I've simulated FE out at 12.5K and held that altitude supposedly single engine. There's nothing in the handbook to use as SE RPM at this altitude so I've just interpolated to get the RPM setting with power at idle - it may not be a correct power setting.

Bad news, allow plenty of time to climb once you've left 10K with full fuel (148 gals) and a light load on a 90 degree day!