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  • #61
    A couple days ago an friend and I headed to central Idaho for breakfast; he in his 180hp straight tail 172 and me in the BH. He had a pilot friend in town and wanted to do some flying so we opted to try out the Flying B for breakfast. The flight over took a bit almost 1.5hrs thought some great country. We saw Mountain Goats, Antelope, Deer and some of the most beautiful views of a few different mountain ranges. Unfortunately we flipped our raft last week and I drowned my phone. The old point and shoot camera took with me isn't as convenient to use and I discovered later on the lens is trashed on it...

    Anyways, here is a few pics.















    By buddies 172 beat in me speed by 5mph but he had to stop for fuel on his way home so I beat him by a solid hour. It also motivated me to get my airframe cleaned up. In cruise on this trip I burned ~8gph at 125mph. After my friend stoped for fuel I decided to try LOP again since we had rearranged the fuel injectors in attempt to even things out. Looks like it runs pretty well LOP; good enough but still not great. I lost 4mph but went from 8gph to 6.5gph.

    Last edited by whee; 08-02-2019, 12:41 PM.
    Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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    • #62
      Cool! Thanks for sharing!

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      • #63
        Super pics Whee, Thanks!

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        • #64
          Remind me again... You have the O-540? That's a remarkable fuel burn!

          At OSH I attended a few of Mike Busch's talks. He is very committed to flying at full MP and adjust the RPM's only. Over Squared. He adjusts the mixture quickly from full rich to full lean. He calls it the "big pull" and says any amount of time hesitating between full rich and full lean puts you in the high detonation zone.
          Rob Caldwell
          Davidson, North Carolina
          EAA Chapter 309
          BH Model B Quick Build Kit Serial # 11B-24B / 25B
          Build Log: https://bearhawk4place.blogspot.com/
          YouTube Channel: http://bearhawklife.com

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          • #65
            Busch is only referring to fuel injection when he talk that procedure. When running Lean, we need to be in the 30-40deg lean of peak. When running rich, we must be minimum 150deg rich of peak. All of this only matters at or above 75% power. The danger zone get smaller and smaller very quickly as you reduce power. At 65% and below, you can do whatever you want with the mixture knob as long as you control CHT’s

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            • JimParker256
              JimParker256 commented
              Editing a comment
              Mike Busch stated (or at least strongly implies) that carbureted engines absolutely cannot be operated LOP, but that is not always true. It depends – a lot – on the particulars of the engine, the induction system, and the particular aircraft. In the Advanced Pilot Seminar, they talked about a technique you could try to see if your carbureted engine/airframe combination can operate LOP. They recommended only doing this if you have an all-cylinder digital EGT monitor. The idea is to first set the power for 65% or less, so you're at a power setting where detonation is not an issue. You then slightly open the carburetor heat – just a crack. Finally, lean the mixture slowly, observing the EGTs until all the EGTs peak and begin to drop. You want to be sure that the last cylinder to reach peak (your richest cylinder) can be leaned to at least 10º below peak EGT. You lean only to the point where engine roughness is apparent. There will be some roughness, but it should not be objectionable. Tweak the carburetor heat adjustment (very small movements) to see if it helps smooth out the engine. If the roughness is acceptable, you can safely continue to operate at the LOP setting.

              Many (most?) carbureted engine/prop/airframe combos will exhibit more roughness than is acceptable. And if that's the case, go back to ROP operations.

              Anecdotally, the Grumman Traveler I used to own (O-320 with high-compression pistons, so ~160 hp) could be flown LOP at higher altitudes – most of the time. There were some days (combo of temp, humidity, phase of the moon?) that it just wasn't possible. Tweaking the carburetor heat was a requirement on the days it would work – it never ran LOP without at least some carb heat.

              Experimental aircraft have another trick that could potentially be employed – an intake "turbulator". The turbulator itself is difficult to describe until you get the visual. To help with that, here's a very rough (and very ugly) version depicted in post #45 of this forum link: https://www.recreationalflying.com/t...d.35663/page-3. The turbulator uses a pair of thin, square-edged (thus "high-drag", which equals high turbulence) flat plates. They are fitted in an "X-shaped" pattern, with the long edges aligned in parallel with the airstream. Of course, it needs to be installed just upstream from the carburetor.

              The principle of the turbulator is exactly the same as "slightly opening the carb heat"... Both solutions introduce turbulent airflow upstream from the carburetor, resulting in "disturbed" airflow that forces better mixing of the air and fuel. The fuel droplets are more likely to be broken up into smaller droplets, and thus mix better with the air. Thus, the air-fuel mixture that flows to the cylinders is a more "even" mix for all cylinders.

              I learned about this from a friend with a Zenith CH-750 powered by a Jabiru 3300. He had a really tough time with very wide EGT spreads (meaning one cylinder would go LOP during leaning operations, while the other cylinders were still well on the ROP side. It made it almost impossible to lean the engine at all... He was burning a LOT more fuel than the factory and other owners reported. The Zenith factory guys (with concurrence from the Jabiru engine importer) recommended installing one of these "turbulators" just upstream from the carburetor.

              I gotta admit, I was pretty skeptical about it when he was telling me about it... After all, it's just a couple of strips of metal that basically parallel the airstream flowing into the carb. (Though the one my friend made on his CNC mill was a thing of beauty compared to the ugly one in that thread picture.) When he first installed his turbulator, he saw some improvement, but was disappointed that it did not do as much as he hoped. The Zenith guys told him to turn it slightly (initially 45º) and re-test. Then "lather, rinse, and repeat" until his EGT spread was optimized. The result was that his engine's EGT spread was significantly reduced, and he could lean the engine and it would remain pretty smooth enough to operate at very lean mixtures. Oh, and by the way, he also found that it was very effective in reducing the CHT of that one cylinder that was always running lean, and had previously run quite a bit hotter than the other cylinders. Win-win!

              In an experimental, such a "turbulator" might be installed at the exit from the airbox, just upstream from the carburetor. Just a thought...

          • #66
            Originally posted by robcaldwell View Post
            Remind me again... You have the O-540? That's a remarkable fuel burn!

            At OSH I attended a few of Mike Busch's talks. He is very committed to flying at full MP and adjust the RPM's only. Over Squared. He adjusts the mixture quickly from full rich to full lean. He calls it the "big pull" and says any amount of time hesitating between full rich and full lean puts you in the high detonation zone.
            I have a Continental IO-360 (210hp).

            Unless I’m loafing around I always run a WOT and set the RPM for whatever power setting I’m looking for. So far it seems this engine/prop combo likes 2350rpm in cruise. At the altitudes I have to fly around here it’s hard to run “over square.” Take the pic I posted above as an example; is getting about 19” at WOT which exceeds the what the performance charts say I should be getting at that altitude. Still, I would like like to figure a system to get a little extra like Battson has on his plane. At my cruise elevations I’m usually close to 65% power, frequently even less.
            Last edited by whee; 08-03-2019, 04:46 PM.
            Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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            • #67
              Originally posted by whee View Post
              Took my sister and brother-in-law to central Idaho for a day of fishing. Was a fantastic day full of fish and hanging out on my favorite river.

              Landing video is all I got so far.


              Here is the takeoff video from this trip. Performance appears to be quite lousy but note the DA was pretty high (7200msl) and we had unstable wind conditions.

              Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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              • #68
                Been busy around my place and the plane is down for some work/adjustments so no flying. Before we took it down I took the whole family for a ride. This moment is what my entire build was for.

                Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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                • AKKen07
                  AKKen07 commented
                  Editing a comment
                  That is wonderful!

                • robcaldwell
                  robcaldwell commented
                  Editing a comment
                  What a great looking family!

              • #69
                Yes!!!!!!!

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                • #70
                  Originally posted by whee View Post
                  Been busy around my place and the plane is down for some work/adjustments so no flying. Before we took it down I took the whole family for a ride. This moment is what my entire build was for.
                  Sent this pic to my wife (she’s already on board, but hesitant still). It moved her a little more into the dream with me, so thanks for sharing! Great family picture!
                  John Wiltberger
                  Model B - #1544B
                  Maricopa, AZ

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                  • #71
                    Great pic Jon. Congratulations. Everyone has a big smile. Mark

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                    • #72
                      Whee how are you finding your side mounted cowl flaps? Are you happy with them?
                      Nev Bailey
                      Christchurch, NZ
                      Bearhawk Bravo, 4 place Quick-build #25B.

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                      • whee
                        whee commented
                        Editing a comment
                        They work great. I’m 100% happy with them.

                    • #73
                      Whee I am so happy for you and your Dad congratulation man!!! You guys must be on cloud 9??

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                      • #74
                        Fantastic, love the smiles ! Stinger

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                        • #75
                          What was your empty weight again whee ? Thought I would find it here, maybe I missed it.

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                          • whee
                            whee commented
                            Editing a comment
                            1398 pounds.
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