I'm thinking about not installing a TCM IO360 and going with something bigger. If I were to do that I'd want to be able to run it at power settings with fuel flow under 10gal/hr without worrying about hurting the engine. I've been able to find a some information about running a O/IO540 at low power and it doesn't seem to mind. Bob Borrows runs his at 19 squared and doesn't have any trouble. What about the big Continentals? Everybody I've asked doesn't know because they never operate there.

You might consider these engines, with EFII. Better performance and fuel economy, and you can run MoGas or AvGas by adjusting the timing settings on the panel.

http://www.titanengine.com/rseries/

"Starting at $46,000"

These engines look AWESOME, but that is just a massive chunk of change (at least for me.)

I'm really excited about this engine series. The R360 has more hp and torque then my O375, burns less fuel, runs cooler, and weighs less. When it's time to change the engine out in the SQ2 it will get an R series motor. The R409 weighs a little bit more the my O375, but with EFII on Avgas about 250hp which is 45 more then I've got now. Be hard to pass it up, but might, to actually go lighter then I am now. The cooler running part is huge at SQ-2 speeds.

In a more direct answer to your question Whee: last year I flew 5 hours at the bottom of the green in my 185 (15mp/2200rpm), with 10 degrees of flaps, to keep up with a bunch of CarbonCub friends. I still had to occasionally do a 360 cause even that was too fast. But I only burned 4 gph (LOP), less then half the fuel burn of the CC's. The biggest problem is keeping the engine running hot enough to discourage lead deposits in the engine.

With the Sportsman STOL and WingX I'll be able to keep up with them without doing the 360's if ever I need to take the 185 again instead of the SQ-2. Can't wait.

I think you might get away with a sustained diet of low power settings in the big Continentals with MOGAS. We tried it with AVGAS and ran into valve problems. Went back to 24" - squared and no more problems. Of course, we seem to find the weak link in just about everything. Lucky that way I guess.

whee wrote:I'm thinking about not installing a TCM IO360 and going with something bigger. If I were to do that I'd want to be able to run it at power settings with fuel flow under 10gal/hr without worrying about hurting the engine. I've been able to find a some information about running a O/IO540 at low power and it doesn't seem to mind. Bob Borrows runs his at 19 squared and doesn't have any trouble. What about the big Continentals? Everybody I've asked doesn't know because they never operate there.

Some relevant info in this thread Whee: https://www.backcountrypilot.org/forum/ ... uise-13385

I usually lope my 470-powered C180 along at about 21" / 2300, that seems to be worth about 11 gph or so.
I have a power chart that under "maximum range settings" shows 20 squared as a high at 8.7 gph, and as low as 17" / 2000 at 7 gph. I know a guy who told me that for local loafing around he runs at 18 or 19" / 2100 and it works just fine. Didn't tell me his fuel burn but extrapolating I'd guess it's also around 8 to 9 gph.

My Bonanza has a 520(285 HP) and I will run it at 19"/2100 when I want to let my friends 182 keep up with me. That's 45% and I lean it to 8.5 GPH. I will also use 19"/2300 and 10.5 GPH.

When flying at "canyon speed" or "air-to-ground photo speed" I'm burning about 5.5 gals/hour on my O-470K. That's about 60 MPH in my 180. Wouldn't do it all day long, but it's certainly happy at that power for the amount of time you'd want to spend loitering at that speed.

hotrod180 wrote:...for local loafing around he runs at 18 or 19" / 2100 and it works just fine. Didn't tell me his fuel burn but extrapolating I'd guess it's also around 8 to 9 gph.

I run there a lot in the 182 (at altitude). Very close to 9 gph at an IAS that a 172 might be able to squeak out at the same fuel flow.

I wrote a reply but it got lost in deep space and I don't have time to retype at the moment. Thanks everybody for the replies so far.

Bonanza Man, How often or how much time do you have operating your IO520 at those power settings. I'm taking a hard look at the IO520C.

I've been building time flying my O-470 at 18/2000 rpm at 7.9gph (5k) at about 110mph.

bigrenna wrote:I've been building time flying my O-470 at 18/2000 rpm at 7.9gph (5k) at about 110mph.

I fly mine right there pretty often as well. Truth is, I am generally not in a hurry when out flying and like to ramble about and scope out the land from my seat.

As long as you're leaned properly for the power setting, I don't see why it would be a problem. You hear concerns of plug fouling or temps not being high enough, but these are functions of mixture.

Right?

Whee
I ran my 180/PPonk between 15 and 18"s a lot in the 1000hrs. I had it. Fuel burn was generally about 1/2 my manifold pressure.
Never any issues. I ran mogas with MMO in it and Avblend in my oil. I would keep my rpms up a little just incase I wanted to add power quickly and didn't want to take a chance on lugging it. Probly around 2400rpm.
Gary

Zzz wrote:As long as you're leaned properly for the power setting, I don't see why it would be a problem. You hear concerns of plug fouling or temps not being high enough, but these are functions of mixture.

Right?

Nope. Maybe. Yes. Depends if your leaning on the ROP side or the LOP side. The additives in 100LL Avgas can keep the lead in a volatile state only if the combustion chamber temperatures are high enough. Leaning the engine at best extends the time it takes for lead to accumulate (by decreasing the amount of fuel/lead going into the engine) or at worst when deep LOP the combustion chamber temperatures drop enough that the additive can no longer do its job so the lead starts to accumulate on things like valve stems and spark plugs.

In the Texas winter running very LOP will get me 300 degrees CHT on the hottest cylinder, about 280 on the rest. Lead accumulates quickly. In the highest summer temps the same leaning gets me about 350 degrees, and I get almost no lead build up. YMMV.

Here is a link to a doc that explains this way better then I can

http://www.shell.com/global/products-services/solutions-for-businesses/aviation/aeroshell/knowledge-centre/technical-talk/techart18-30071600.html

Can NOT explain it but I burn 9.8gph in my 180 at 23 squared.
With bushwheels and bubbles and all kinds of dirty stuff hangin on it I average about a 135mph at 9.8 gph at that setting. Not bad mpg.

whee wrote:I wrote a reply but it got lost in deep space and I don't have time to retype at the moment. Thanks everybody for the replies so far.

Bonanza Man, How often or how much time do you have operating your IO520 at those power settings. I'm taking a hard look at the IO520C.

Hard to say how much time. Lots of Saturday flights around the local area so maybe a couple hundred hours worth over the last 10 years.

good question Jon...

i think u r on the right track...my experience with the cont. 470 was that it was o.k...
360 IO would be a better fit i think...my O-540 i really like...whisper smoothe...lots of torque...runs really clean at about any settings, as b.m. said its the mixture settings that make it work so well...im always a bit rich of peak...but if u think u want to run mo-gas, i wouldnt do a big bore...the 360's and such do that better i believe...i know u CAN run mogas, but not sure why ....the chance of issues is much greater, and i see a bunch of motors that end up getting 1/2 the hours with mo-gas...i know, some do seem to make it work...i have simply decided that most of my time over some rough country and a lot of nite ops, i want as much in my favor as possible...

Years ago I was partnered in a TR182, just about the time the feds decided that commercial applicants needed X hours of complex time. Ours was the only complex on the field that could be rented--the FBO put it on their insurance policy, so it wasn't anything out of our pocket, and that way our partnership qualified as a business for IRS purposes. But one of the renters started bragging that by cranking the power way back, he could still get decent airspeed and really phenomenal GPH figures--I don't recall what they were. But very soon, we started having a lot of plug fouling problems, and the local mechanic told us to expect valve troubles if we continued to allow that sort of operations. We couldn't seem to get the message across to that renter. For that and one other reason about the way he was operating the airplane, we just barred him from renting it. The plug troubles went away, and for the entire time we had the airplane, we had no valve troubles--plenty of other problems, as it qualified as a hangar queen, but no further engine problems.

Cary