20 Apr 2024, 05:24 [ UTC - 5; DST ]
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 01:33 |
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Joined: 12/19/09 Posts: 332 Post Likes: +272 Company: Premier Bone and Joint Location: Wyoming
Aircraft: BE90,HUSK,MU-2
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Username Protected wrote: I fly mine at 20deg below EGT redline at 97% engine speed (as recommended by Honeywell’s engineers when I bought it) which usually burns 75-80gph and yields around 310-315kts. It usually cruises pitched up about 2.5 degrees according to the G600 and the other two independent AI’s. I bought mine from Mike Laver. He owned my 50AF before his current -ED. He’s a very honest guy. Based on his reputation, I bought mine without pre-buy and very little has gone wrong in 5.5 years. Thomas, What Honeywell engineers?
Hellmuth Eggeling
_________________ Thomas
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 04:14 |
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Joined: 08/09/11 Posts: 1732 Post Likes: +2053 Company: Naples Jet Center Location: KAPF KPIA
Aircraft: EMB500 AC95 AEST
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Username Protected wrote: Hellmuth Eggeling
The pilot advisor. He was great. Too bad there seem to be no videos of his presentations re: proper ops and reasons for them. Those talks where he fielded questions from the crowd were always interesting and usually put a few OWT to bed.
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 07:33 |
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Joined: 06/18/15 Posts: 567 Post Likes: +216 Location: Idaho
Aircraft: Helio Courier, MU2
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Username Protected wrote: I fly mine at 20deg below EGT redline at 97% engine speed (as recommended by Honeywell’s engineers when I bought it) which usually burns 75-80gph and yields around 310-315kts. It usually cruises pitched up about 2.5 degrees according to the G600 and the other two independent AI’s. I bought mine from Mike Laver. He owned my 50AF before his current -ED. He’s a very honest guy. Based on his reputation, I bought mine without pre-buy and very little has gone wrong in 5.5 years. From the pictures it looks like the subject airplane was 50C below the limit which is a huge difference from the power setting in the performance chart
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 10:01 |
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Joined: 12/19/09 Posts: 332 Post Likes: +272 Company: Premier Bone and Joint Location: Wyoming
Aircraft: BE90,HUSK,MU-2
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Username Protected wrote: Hellmuth Eggeling
The pilot advisor. He was great. Too bad there seem to be no videos of his presentations re: proper ops and reasons for them. Those talks where he fielded questions from the crowd were always interesting and usually put a few OWT to bed.
Agreed. He had an outstanding capacity to explain things in a way operators understand. I have been disappointed by some of the folks from Honeywell and MHIA at the PROP seminars when fielding questions since Hellmuth’s retirement.
_________________ Thomas
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 10:05 |
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Joined: 10/09/21 Posts: 14 Post Likes: +1
Aircraft: Lancair Legacy
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There is a sideslip indicator, and it's pretty much centered; maybe a hair left. Attachment: Screen Shot 2022-01-08 at 7.38.54 AM.png Attachment: Garmin slip skid indicator.png The airplane was on autopilot so it's possible there was some yaw servo push on the rudder -- dunno. The control wheel was centered, so spoilers down. I understand higher ITT being available, but the fuel burn was what it ought to be for 289 kt (if you believe the manual). I had already noted (actually, Land Creson noted) the split in the torque gauges at exactly matched fuel flows and ITTs on my (previous) demo flight and squawked it; they should have been fixed prior to this acceptance flight and Mike Laver agrees they need to be fixed. I wonder if either of the torque gauges was indicating correctly. But... back to speed vs fuel flow -- it's just dang slow for the fuel flow.
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 11:23 |
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Joined: 06/18/15 Posts: 567 Post Likes: +216 Location: Idaho
Aircraft: Helio Courier, MU2
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Username Protected wrote: There is a sideslip indicator, and it's pretty much centered; maybe a hair left. Attachment: Screen Shot 2022-01-08 at 7.38.54 AM.png Attachment: Garmin slip skid indicator.png The airplane was on autopilot so it's possible there was some yaw servo push on the rudder -- dunno. The control wheel was centered, so spoilers down. I understand higher ITT being available, but the fuel burn was what it ought to be for 289 kt (if you believe the manual). I had already noted (actually, Land Creson noted) the split in the torque gauges at exactly matched fuel flows and ITTs on my (previous) demo flight and squawked it; they should have been fixed prior to this acceptance flight and Mike Laver agrees they need to be fixed. I wonder if either of the torque gauges was indicating correctly. But... back to speed vs fuel flow -- it's just dang slow for the fuel flow. It’s not a slight skid that’s reducing speed 36kt. There are actually a myriad of possible explanations, some plausible and some unlikely. Descending air from a mountain wave system can easily reduce speed that much. If one wants to solve this riddle then the plane has to be flown to the numbers in the book which are the temp and torque limits. Then see if the engines make the numbers in the power assurance chart and the plane makes the book climb and cruise numbers
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 11:29 |
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Joined: 06/09/09 Posts: 4573 Post Likes: +3298
Aircraft: C182P, Merlin IIIC
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At what altitude do MU2 typically become temp limited?
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 11:59 |
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Joined: 11/08/12 Posts: 6311 Post Likes: +3806 Location: San Carlos, CA - KHWD
Aircraft: Piaggio Avanti
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Username Protected wrote: At what altitude do MU2 typically become temp limited? My Solitaire temps out about 16k’, generally. Yesterday it was unusually cool (ISA minus something, which I almost never see) and it went to nearly 18k before temp limits.
_________________ -Jon C.
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 08 Jan 2022, 17:02 |
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Joined: 10/09/21 Posts: 14 Post Likes: +1
Aircraft: Lancair Legacy
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Username Protected wrote: It’s not a slight skid that’s reducing speed 36kt. There are actually a myriad of possible explanations, some plausible and some unlikely. Descending air from a mountain wave system can easily reduce speed that much. If one wants to solve this riddle then the plane has to be flown to the numbers in the book which are the temp and torque limits. Then see if the engines make the numbers in the power assurance chart and the plane makes the book climb and cruise numbers Mike, I agree completely -- there are MANY pitfalls. One of the most disciplined Lancair aficionados finally figured out that he was 7 kt down on a particular test point because he was flying in a high pressure system and there's a net downdraft or subsidence in a high. So he was having to "climb" just to stay level. There is not enough data in this one point to figure out N3GT's real performance. My problem is that the only way I can really diagnose it is by buying the airplane and sorting it out ... which could be very expensive.
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 09 Jan 2022, 09:43 |
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Joined: 03/23/08 Posts: 6945 Post Likes: +3605 Company: AssuredPartners Aerospace Phx. Location: KDVT, 46U
Aircraft: IAR823, LrJet, 240Z
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Username Protected wrote: At what altitude do MU2 typically become temp limited? A -6 can temp out on the runway. In summer in AZ it is already behind. Big difference from a 10. No -6 is gonna true 289 at FL250. Although I’m sure somebody will show otherwise.
_________________ Tom Johnson-Az/Wy AssuredPartners Aerospace Insurance Tj.Johnson@AssuredPartners.com C: 602-628-2701
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 10 Jan 2022, 00:53 |
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Joined: 03/23/08 Posts: 6945 Post Likes: +3605 Company: AssuredPartners Aerospace Phx. Location: KDVT, 46U
Aircraft: IAR823, LrJet, 240Z
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Username Protected wrote: Checked mine on a short flight at 17,000 today. Torque limited throughout climb and then limited by Vne (250 IAS) at 17,000. ISA 0. Judging from trend, I’d say the temp would have become limiting (using 20 less than actual limit) at maybe 18,000 or FL190 in today’s conditions. -5, -6, -10?
_________________ Tom Johnson-Az/Wy AssuredPartners Aerospace Insurance Tj.Johnson@AssuredPartners.com C: 602-628-2701
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 10 Jan 2022, 06:42 |
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Joined: 05/29/14 Posts: 1369 Post Likes: +434
Aircraft: Mooney M20J
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For those of us in warmer climates, don’t try to make book numbers. They’re based on ideal conditions, which we never see. I’ve never seen ISA temperatures and humidity alone can rob you of up to 10% horsepower.
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Post subject: Re: MU2 Pre-buy speed 36 ktas below book Posted: 10 Jan 2022, 07:51 |
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Joined: 12/19/09 Posts: 332 Post Likes: +272 Company: Premier Bone and Joint Location: Wyoming
Aircraft: BE90,HUSK,MU-2
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Username Protected wrote: Checked mine on a short flight at 17,000 today. Torque limited throughout climb and then limited by Vne (250 IAS) at 17,000. ISA 0. Judging from trend, I’d say the temp would have become limiting (using 20 less than actual limit) at maybe 18,000 or FL190 in today’s conditions. -5, -6, -10?
-10 And technically, once you are airborne at speed and Vmc is no longer a concern, you could push the Tq to 110% which is the level of Tq the long bodies have listed as their 100% with the same engine. I don’t do that because I usually just leave the protective torque limiter on all the time. And “pretty soon” Temp becomes limiting in the climb anyway. That’s why the Tq gage on short bodies doesn’t have a radial red line at 100%. The color changes and ends at 110%. At least that’s how it is denoted on my instruments.
_________________ Thomas
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