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  1. P

    Aircraft Design sanity check

    Thanks Duncan. Helps with the bandwidth. Cheers. oh. by the way, Dec1990 is from the previous set. That wasn't available in print. Otherwise, quality should be better than in previous set, one should be able to tell whether there's an asterisk, hyphen or accent in equations. Not pristine...
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    Aircraft Design sanity check

    John Roncz - Designing your homebuilt - clean scans - part 1-12 The set is ready. Just that it's 61MB zip and my website's bandwidth quota is exceeded already... Seeded it to Torrent network. If you have an access to this, search by a name: EDIT2: seemingly takes ages to propagate. Please use...
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    how can the DA42 be so heavy ?

    For the reasons you just described, and due the effects of cooling drag, I'm not too concerned about speed specs either... But weights... Reliable FWF for IO-360 and thielert difficult to find, but let's use this for starters: from: Photos for Kumaros [Archive] - Canard Aviation Forum...
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    how can the DA42 be so heavy ?

    Sometimes it pays to be a subscriber of Flying magazine ;) Diamond Twins Reborn | Flying Magazine | The World Empty weight, useful load (lbs), engine, cruise@8k 75%: DA42 NG 3119 1070 (austro 170 hp) 170kt DA42 TDI 2761 1174 (thielert 135hp) 161kt DA42 L360 2755 1180 (lycoming 180hp)...
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    Wright Cyclone R-2600-20 engine SFC

    According to Graham White, R-2600-20 was used on: - TBM-3 Avenger - SB2C-3 and -4 Helldiver Information like fuel consumption/power and BSFC could be sometimes found on aircraft's manuals. Curtiss SB2C-3, -4 Helldiver Pilot's Handbook US Navy and ebay I think here was a couple of graphs from...
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    Reduction drives

    This has been my concern too. I was going to order one 6-planet unit and disassemble it to get exact dimensions of bearings - to make some sense about this TBO issue. There is presumably needle bearings inside, and from their dimensions can be made an educated guess of how long they last on a...
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    New seaplane designs

    I dare to start a new thread :) just to say congratulations for this new design: Privateer Industries - The First New Amphibian in over 60 years.... This is so... "obvious"... but then again, good ideas are! Kudos! Also, there has been this other company, Gevers Aircraft with their Genesis...
  8. P

    Stratospheric flights - engines

    No worries. Getting back with engine matters when done with turbo calcs. Cheers.
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    Stratospheric flights - engines

    I agree, completely. In this discussion, there's this implicit idea that "Escape procedure after loss of pressure suit integrity above 50 000ft" is executed by autopilot (originally Jarno's idea) max dive procedure, that flies the plane to pressure-safe altitude (soon enough) where oxygen mask...
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    Stratospheric flights - engines

    Actually, that 0,2 atm represents 38 700 ft. So, from 15km/18km there's 10 512/20 355 ft to go to "pressure safe" altitude. Human terminal velocity down low is... abt. 195 km/h or 10 662 ft/min. At 15 km it's likely valt= vlow * (pres.ratio)^-0.5 = 0,158^-0.5 * 10 662 ft/min = 26 823 ft/min...
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    Stratospheric flights - engines

    Sources in this text seem to support your view. In case of "explosive decompression", 12 seconds to unconsciousness, but if able to return to 0,2 atm within 60-90 seconds, generally no ill effects afterwards. Explosive Decompression and Vacuum Exposure If speed brakes can keep the plane...
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    Stratospheric flights - engines

    Armstrong Limit - Wikipedia, the free encyclopedia So, it seems that 15 km can be reached almost safely with pressure oxygen system, like the one that Bohannon was using. Just that the safety margins would be much better if the plane can still have a good climb rate up to 15km, so that exposure...
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    Stratospheric flights - engines

    Um, actually... rather counter-intuitive, but perhaps... in extreme altitudes, Vulcan-like low Swet/Sref delta could be comparable to high AR configuration, like in B-47 vs. Vulcan case. Delta layout would help with both weight and divergent mach number. If sailplane-like layout like Grob...
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    Stratospheric flights - engines

    Just checked some airframe/engine/turbo combinations with your spreadsheet. With higher power engine on Harmon Rocket III, after 60 000 ft arises other problem. Even HR-III's Vne (369 mph) is exceeded on L/Dmax - and it has shorter and stiffer wings than RV-4... (20 ft vs. 23ft - lower L/D -...
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    Stratospheric flights - engines

    Well, Andrew... you don't really think this talk is about air conditioning? ;) You are right, the thing with intercoolers is the most challenging point here. At some height, we will run out of fuselage volume, weight allowance, or cooling drag allowance. I remember that I have seen somewhere a...
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    Stratospheric flights - engines

    FWIW, there seems to be three 'design branches' for a high altitude plane. HALE - long endurance, optimized for loiter time HALR - long range optimized, that's something new... HASE - short endurance, optimized for climb like Bohannon B-1 or altitude like Caproni Ca. 161 (that AVweb's article...
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    Stratospheric flights - engines

    There is a SAE paper #871041 - that is about Continental aircraft turbo project. They started by modifying a TP500 turboprop's titanium impeller to use it on aircraft turbocharger. That impeller is originally a 8 pr unit, and after modding they were able to get a pr of 6. Weight was 28 lbs...
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    CG Envelope - Winglets

    Hello Eduardo, Here: http://www.protonet.org/doc/sav-1990-04-Rutan-.pdf Very worthwhile article. After I read it, I promised to never say again "Burt Rutan" and "Plastic Gizmos" in a same sentence. :emb: He's actually WAY much more sensible... than was my initial impression. And what comes to...
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    Stratospheric flights - engines

    Re: 80,000 ft Triple-Turbo & other thermodynamics lectures by pie_row First thing that comes to mind is that PT6 will likely flame-out - combustion goes out of envelope. Not sure, though, but strong hunch ;) And... I'm one of those characters that offer the Rotary Engine as a solution to...
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    Stratospheric flights - engines

    Re: 80,000 ft Triple-Turbo & other thermodynamics lectures by pie_row Grob Strato 2C - Wikipedia, the free encyclopedia There is link to interesting NASA paper on "Bibliography" section: "Propulsion System for Very High Altitude Subsonic Unmanned Aircraft" This image illustrates the problem...
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