I have an o550 conversion in a 1973 specimen. It's not quite airplanes, but it's nowhere near those numbers. I can get 140kt down low, if I want to drink 15gph... Maybe 145 with pants on.

I have an o550 conversion in a 1973 specimen. It's not quite airplanes, but it's nowhere near those numbers. I can get 140kt down low, if I want to drink 15gph... Maybe 145 with pants on.

uote="Jonathan Knight"]

I have an o550 conversion in a 1973 specimen. It's not quite airplanes, but it's nowhere near those numbers. I can get 140kt down low, if I want to drink 15gph... Maybe 145 with pants on.

The G500 did that 162kts TAS math at 6,500 albeit at 18.5 gph

I more regularly fly NOW N182AP LOP WOT / 2400 RPM at 14.5 gph and see 152 kts TAS at 5,000 to 7,000 msl

Cannot say enough positive about the IO-550, but if you add the IO-550 plan adding Flint Aero internals for another 24 gallon / 98 gallon usable

900 kts range

Mike,

How do you lean this thing so aggressively? I can't get the burns down that low. Let me know your secret and what values you use for EGT/CHT.

In order to get 14 or less, I have to go to 8,000 or so and it would never happen firewalled. I pull it back about 20-25% because I don't get any higher manifold pressure and just end up wasting fuel.

At 3-5k, I would be burning 15-16GPH and getting 140kts for my efforts (no pants).

Carb heat.

Huh? Are you saying that you cruise with the carb heat ON? Now that's really interesting.

Tell us more, Mike.

IIRC a bit of carb heat allows for a more uniform range of mixtures between the cylinders. For those who want to run LOP and not have one cylinder so lean that it quits while another is just starting to fire and warm up.

Huh? Are you saying that you cruise with the carb heat ON? Now that's really interesting.

Tell us more, Mike.

Huh? Are you saying that you cruise with the carb heat ON? Now that's really interesting.

Tell us more, Mike.

I too cruise with a bit of carb heat. At AirVenture, the Insight engine monitor booth was where I first heard about it. They recommended that I to go ask the GAMI booth for details. IIRC, every engine has a "sweet spot" to how much carb heat it likes, so I played around to find mine.

Running carb heat in cruise allows me to lean further than without the carb heat. Since warmer air is less dense than cooler air, fuel can be leaned further. Of course this reduces performance. Everything is a compromise. It's just a cheap-skate method of reducing fuel burn. I'm running a pinch of carb heat/ 2100 RPM/ 21" MP @ 10.7 GPH. CHT's easily remain way <380. It's about 67% power which is said to be easy on the engine. Some say you can't hurt an engine when running <70%, but I know some guys who can wreck anything. Running like this is surely a couple of knots slower. I might get there a bit later, but I'm stretching my flying dollars.

Note that I'm flying a 182RG which has a Lycoming O-540-J. The carb isn't in a cold location as discussed in the thread drift. My carb is mounted in a hot spot on the very back of the engine so I can't contribute to that part of the discussion. Also, at my settings which I described, my Insight G2 shows that I'm not running LOP, nor ROP, but running at "Peak". If running at peak causes marginally higher cyl pressure, it's not an issue for my derated Lycomong with durable Lycoming cylinders. However, if I had a Continental with chronic cylinder problems, I would do further checking to find out if peak cyl pressures contribute to premature cyl failure.

This is a shot of my JPI, cruising at 10.5, leaned to burning 12.5gph, with a TAS of 144kts. I got up to 13.5 recently and the fuel burn was down to 11.5, and a TAS of 142kts. Really love this pponk engine with the MT prop, very smooth and, for a 182, fast.

I got to ride with Larry S yesterday in his PPonk 182. I caught myself watching the world go by like a non-pilot passenger. There is nothing like suspending yourself from a high wing over beautiful terrain. And yes, his 182 runs incredibly smooth and he likely won’t get lost with 7 screens on the panel.

Thanks again Doc.

Two comments on previous posts. To Larry and Jesse, thanks for the experiences with the PPonk. If my 180 ever sees enough flying to put it to overhaul, the PPonk conversion will likely be the route I take.

As to the comments on the tendency of the Skylane engines needing carb heat, I completely agree. A carb air inlet temp gauge is almost a necessity with these O-470's. I'm having one installed in my 180, via the EDM 930, now.

Jg

Pictures or it didn't happen...