1) I just submitted an article to Velvet for publication on exhaust leaks and it'll be out sometime in the future. I'll consider publishing it here as well after I visit with Velvet.AR Dave wrote:Joe, I'll try again when I get 3 weeks off in Feb, this morn I have a nice fire burning and the wonderful thing is I didn't need to cut 10 cords of wood this winter.
I also have several questions this am: If new subjects are needed, feel free to transfer:
1.. This week I'm planning on buying some Victor, 1 1/4", Red, Fiberglass Tape, and seal the exhaust leaks under those clamps. I get 6 -10 ppm CO when the cabin air is open. However, the biggest leak looks to be from one of the exhaust gaskets itself at the cylinder. I looked through the Search, but didn't find any mention on gaskets. Instead of the tin gasket, is there anything better?
My mechanic has a thicker gasket that worked on another plane. It is copper looking with white asbestos sandwiched in between. Oreo cookie style.
When opening the Cabin Heat the CO rockets, so I've got to get it welded again while working on this. Dakota and I flew home in our sleeping bags. I am so glad I invested in a CO monitor.
2.. George, how do I figure 65% of power? I was flying at almost 2000 ft and not sure how much to lean the engine. Any tutoring in this area would be appreciated.
3.. Someone has put the bug in my wife's ear that we need a Piper 6, with the 260 hp engine. The specific one is $67K. Remember, I've only flown 1 plane & don't really consider myself a pilot. Should I try a Piper 6 on? Theory: The entire family can climb in + cousins + luggage and fly over the VFR. But I do want to retire someday too!
The best gaskets for the exhaust riser to cylinder flange are the spiral-wound types. The official PN is: RA-627429 (RapCo brand) available from Spruce 877-477-7823. The Superior PN is SA 627429. Don't be surprised to find it necessary to grind a little excess flange material off the gaskets to slip them on without interference from the adjacent intake elbow. (Avoid the "oreo" types and the flat copper types because they don't stand up.) If you replace one, consider replacing them all on the same side of the engine because their additional thickness may make it difficult to re-fit the muffler to all the risers simultaneously. (A thicker gasket flange will drop the other end of that riser enough to make a difference.)
If you wait too long the cylinder flange will erode to the point it will never seal without cyl. removal and welding/re-machining.
) Use new exhaust nuts (Spruce PN 22022) when removing/installing the exhaust risers. (Just for convenience, here's the PN's for the clamp hardware also: (AN363C-1032 nuts, AN960C10 washers and AN3C-4A bolts)
If your risers are so worn their flanges are bowed, you should consider replacing them with new ones from Knisely Exhaust, Loomis, California (800-522-6990 or 916-652-5891) who makes them with nice thick flanges.
The risers are Pn’s 0550157-7 for the short straight ones (4 req’d each engine) and 0550157-8 for the longer curved ones (2 req’d each engine).
2) Power setting charts are found in the Owner's Manual. 65% pwr at 2000 ft is about 2450 RPM. At any power setting lean in accordance with the following procedure (no egt req'd): Set cruise power (2450 RPM recommended) and after conditions stabilize slowly lean until max rpm is found. Continue slowly pulling mixture control until first indication of rpm loss occurs. Enrichen (push mixture control back in) to max rpm position. That's it!
I personally leave the mixture in this position until I shut down at the chocks, unless I select a new (higher) power setting or different altitude for cruise or decide to abort a landing and go around. I also lean the mixutre control to about the half-way position to max rpm during climbs, starting just after departing the traffic pattern. Above 5K MSL I lean more aggressively during climb. (because no power setting I can achieve with my cruise prop above 5K' will exceed 65%, i.e., 65% @ 5K is 2550 RPM and I can't get that except in level flight or descent at that altitude. You cannot hurt this engine by leaning at pwr settings below 65% no matter how aggressively you lean.)
How does the above leaning procedure work? The rpm will continue to increase with leaning until the leanest cylinder begins to lose efficiency due to a too-lean condition, at which point the rpm will show the first sign of decreasing below the maximum just-achieved. Enrichening back to max rpm will put that cylinder back at max efficiency and therefore max rpm. All the other cylinders will be running richer than that leanest cylinder. Since leaning aggressively at/below 65% is not harmful to the cylinder, it is unnecessary to have any additional instrumentation than the tachometer. (And tach accuracy is unimportant for leaning purposes.)
3-Piper 6's are not the worst airplanes in the world, but they are far from the best in their price range. The 260 hp version is underpowered. And hot in the summer because of the greenhouse effect of that cabin sitting on top of that leaking wing. And the parts-supply-house is the junk yard. Piper doesn't make any parts for that airplane anymore.
Unlike Cessna 206's,...which will haul anything you can put in 'em, no model of which is underpowered, and which will jump off of 800 feet at sea level and 1800 feet at Telluride, Colorado. I know. I've done it. In a normally aspirated, 285 h.p. 1964 Cessna 206 I once owned and that I regret having ever sold. (And the cabin is shaded in the summer by that high wing which will give you a better view of the landscape, and the main landing gear doesn't have any leaky oleos.) It ran 144 kts burning 12 gph average, same as a 182, but hauled twice-the-load. Cessna still makes them and will sell you any part you need (although you might not like the price, at least you won't have to rely on the junk-yards and worn-out parts from wrecked airplanes.) And they fly just like a 170 with better ground-handling and higher cross-wind capability. I recommend non-aspirated versions unless you like to live on oxygen.