27 Apr 2024, 22:52 [ UTC - 5; DST ]
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Post subject: Re: You say you want an Evolution ... Posted: 11 Mar 2018, 17:28 |
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Joined: 08/15/11 Posts: 2398 Post Likes: +1063 Location: Mandan, ND
Aircraft: V35
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Username Protected wrote: ...And what does % Ng mean... NG is the RPM of the Gas Generator section of the PT6A, measured as a % of 100% NG speed. For example, a PT6A-21 has a NG 100% RPM of 37,500 RPM, and a max RPM of 38,100 RPM (101.5%). Just easier to measure NG as a %.
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Post subject: Re: You say you want an Evolution ... Posted: 12 Mar 2018, 00:06 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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Username Protected wrote: NG is the RPM of the Gas Generator section of the PT6A which drives the accessory drive that drives the supplementary alternator that, even at 97%, is only putting out 56v instead of the 70v that it would if it were turning at the proper speed. Hence the need for a change in pulley sizes.
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Post subject: Re: You say you want an Evolution ... Posted: 13 Mar 2018, 02:44 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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Username Protected wrote: Dave, isn't the heat equation fiendishly complex for an airplane in icing conditions? It can be, although the work has already been done: http://www.fzt.haw-hamburg.de/pers/Scho ... -08-31.pdfVillinger uses the same deicing scheme as the Boeing does on the 787, with always-hot parting strips and cycling heat in shedding zones. Scaling the 787 (60m wing span, swept) down to the Evo (37' span, straight), the 100a, 70v alternator looks adequate to satisfy the calculations in the paper. That said, the flight testing was done to measure the maximum heat available. Nobody is claiming that will always be enough to handle all icing conditions, just trying to see how much capability is there. Note that I'm not involved in the design or testing of the system, although I know people who are. I'm just an interested customer. I have to say I'm more confident of the capabilities of this system than in either of the other de-ice systems available for the Evo.
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Post subject: Re: You say you want an Evolution ... Posted: 13 Mar 2018, 08:22 |
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Joined: 11/07/11 Posts: 724 Post Likes: +413 Location: KBED, KCRE
Aircraft: Phenom 100
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7kW of power, wow, that's awesome.
Where is the temperature of the zones measured?
Chip-
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Post subject: Re: You say you want an Evolution ... Posted: 13 Mar 2018, 13:28 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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Username Protected wrote: Where is the temperature of the zones measured? They put 19 thermocouples on the airplane for the test flights to cover each heating zone but they didn't say where they were placed within each zone.
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Post subject: Re: You say you want an Evolution ... Posted: 13 Mar 2018, 14:56 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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The paper also says that at high speeds, ram heating dominates and accretion falls off. As it notes, the goal is to find the maximum power required so it can be simplified down to finding the power required in whatever is the worst case for this system design. Note also that by "area" it means the "sieved area", span x average wing thickness, so swept vs. straight wings is not a factor.
Assume that the worst case conditions in their 787 analysis fall within the performance range of the Evo (if they don't, then the power required for the Evo would be less than the 3.61 kW/m^2 they calculate for the 787, meaning this would be too pessimistic an estimate). Simply scaling the 787's 60m span down to the Evo's 11m span gives an estimate of (11/60)^2 * 75 = 2.5 kW but I'm sure the Evo's wing is proportionally thicker than the 787 wing, although I don't know how much. Call that a lower bound estimate. For an upper bound, even if the Evo wing were physically as thick as the 787 wing, which of course it isn't, that would give an estimate of (11/60) * 75 = 14 kW. So even if the Evo wing's physical (not proportional) average thickness were half of the 787s, which I'm sure is still way too high, we get an estimate of 7 kW. Very rough estimates, but they do seem to put the Evo system's power in the right ballpark.
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Post subject: Re: You say you want an Evolution ... Posted: 24 Mar 2018, 01:01 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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Prepping the wings and tail for the Villinger guys to come and work their magic. First step is to put down a layer of fiberglass to insulate the electric bits from the carbon. Attachment: IMG_20180320_105858919.jpg Attachment: IMG_20180319_132910912.jpg Attachment: IMG_20180320_105835494.jpg
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Post subject: Re: You say you want an Evolution ... Posted: 24 Mar 2018, 01:42 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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With Evolution Aircraft's continuing downward spiral, I thought it prudent to insist I get what I could of the remaining parts owed me, principally avionics, out of the building before the doors were locked for good. They needed a few days to assemble everything, but when we went over they had things waiting for me. Attachment: IMG_20180321_105431181.jpg Attachment: IMG_20180321_105436233.jpg Attachment: IMG_20180321_105444146.jpg Attachment: IMG_20180321_105448696.jpg They came up with more than I expected, all of the expensive electronics. The biggest things missing are the wiring harnesses, not built yet. They say mine are on the schedule to be wired up in mid-April and suggested I keep everything together so it will be easy to bring back then to finish the panel.(!) EAC has become the Schrodinger's cat of aircraft companies, both alive and dead simultaneously. Driving up, there were just 5 cars in the lot and a sign on the door saying the company is CLOSED, if you need access call a number and someone will bring a key. But inside, they talk as if they have everything under control, they're not going bankrupt, just minimizing cash flow while negotiating with potential investors. Two different visions of reality. I guess in mid-April we'll see which vision is correct.
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Post subject: Re: You say you want an Evolution ... Posted: 24 Mar 2018, 16:04 |
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Joined: 06/17/14 Posts: 5031 Post Likes: +1956 Location: KJYO
Aircraft: C-182, GA-7
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Was it financing that killed them or the inability to get manufacturer’s (or parts manufacturer’s) liability insurance?
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Post subject: Re: You say you want an Evolution ... Posted: 24 Mar 2018, 19:35 |
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Joined: 11/22/12 Posts: 2608 Post Likes: +2372 Company: Retired Location: Lynnwood, WA (KPAE)
Aircraft: 1993 Bonanza A36TN
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Username Protected wrote: Was it financing that killed them or the inability to get manufacturer’s (or parts manufacturer’s) liability insurance? Neither. I don't know where the speculation about manufacturer's liability came from, I've not heard it mentioned by anyone with knowledge of EAC's financials. In my discussions with those who do have knowledge of the company's financials it has never once come up. As for financing, EAC has no debt to banks or suppliers and the building is owned by the family of the owner, Bob, so it's not likely to be pushed into bankruptcy. Bob could finish up the remaining planes, let everyone go, put the keys in his pocket and sit on the company until the cows come home, waiting for someone to meet his terms. Which seems to be his plan, as far as I can tell. Bottom line is that EAC just didn't have enough sales to cover their overhead and Bob got tired of funding it. In my discussions with principals in bidding for the company their plans focus on running it more efficiently, reducing costs to match the sales, and opening up to ideas for improving the plane. In reaction to the safety reputation Lancair acquired, Evolution strove to maintain commonality, but that limited room for builders to experiment. Without builders doing free R&D, all product improvements had to come from EAC itself, which they couldn't afford. It was hard to justify paying more to buy a kit from the factory and spend a year building when one could buy a nearly identical plane used and fly immediately.
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