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Homebuilt Aircraft & Kit Plane Forum

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    Onan Engine Info

    You'd be better off looking at the V-twin conversions of Briggs/Kohler. They are still in production, have good parts availability, and offer more power in that weight range.
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    First Composite Homebuilt?

    Lots of experiments with composites during WW2. The P-51F had composite access panels. I'd guess that the first use of composites in homebuilts would be similar.
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    Aileron add-ons - What is this?

    The Helio had these. Koppen said it was to increase stick force because the FAA said the ailerons were too light.
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    Flying Pancake aircraft for bush operations

    STOL is about having enough thrust to match drag at low speed, weight on its own doesn't matter much. The V-173 had a power to weight ratio of a bit over 14, not very far off the C-152 which is around 15. But it had gigantic props that were geared down to under 500rpm that generated a large...
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    Common / Useful Design Metrics for Aircraft Comparison?

    Gabrelli-Von Karmen; Dividing the speed by the G (P/WV) results in a "score" that makes comparing different aircraft easy. The maximum line = 6000 Another is Pazmanys efficiency score, which is what led to CAFE; = (Vmax/Vso)*(cube root (S/P))*(square root (W/S)) CAFE 250, this was used in...
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    Questair Venture vertical tail?

    Vertical; Area = 9sqft Span = 4.13ft Arm = 7.76ft (just 28% of span!!) Coefficient = 0.036 And the horizontal for the sake of it Area = 12.56 span = 8.66 Arm = 7.91 (3.1x MAC) Coefficient = 0.557 Source is a 3-view from a NACA report that was then scaled to the correct dimensions then...
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    Kitty Hawk, the electric aircraft moonshot backed by Larry Page, is shutting down

    That depends on the sort of range you are willing to accept. Current Lipos, at their best, are around 120w per lb. Going off wikipedia, the R44 uses 15gal an hour. Assuming a BSFC of 0.45 that is about 200hp an hour, or ~150kw. That would require 1250lbs of Lipos.
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    Briggs & Stratton Vanguard 23hp build

    I read Fred Weick's propeller book recently and he makes this interesting point about gearing; The formula for Cs is; 23hp engine @3000 rpm; The speed where it goes over 1.3 is ~94mph
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    Why isn't the push/pull twin more popular ? What you say.

    Rutan said he went with the boomerang arrangement to avoid the noise and vibration problems of push-pull.
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    Whatever happed to Synergy by McGinnes?

    The original EZ prototype different from the final variEZ pretty significantly. Now to stay on-topic, I'm looking forward to seeing how the reduced RCS of synergy will be tested. I think that would be a first for a homebuilt.
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    Land ownership ?

    "It’s clearly seen in the photos the Japanese took of the United States back in 1938" Are those photos available online?
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    Wing loads

    This is from McMasters; And this is from a book I can't recall the name of; And my own data for single seat homebuilts; Spanloading here is mtow/b^2 List of aircraft in the above two charts
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    Understanding Marcel Jurca

    A squared off edge can lower control forces on ailerons/elevators/rudders. I think the rule of thumb is to make the edge ~1% of chord. TOWS would give the pertinent details. I think the bit in pic 4 is a way of saying "stick to the plans" that was translated poorly.
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    Another nail in the coffin...?

    Everything has insane lead times and costs, from server racks to flower pots. Its almost like JIT was a bad idea.
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    Van's announces highwing RV-15

    Based on the numbers he says, 12.7 gal @ 150hp, that works out to ~0.57 bsfc. That is quite a bit higher than the <0.42 bsfc most lyconentals can to when leaned out in cruise. But if you can find Jet-A for less than 3/4ths the costs of LL then its about the same $ - ignoring the possibly...
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    Electric homebuilt aerobatic glider

    The Radab Windex is pretty close, except its not a homebuilt and its been out of production for ages.
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    Yeah, a early mark dynamically scaled to around 75% is perfect for an LS3. With that engine around 400hp it will have the right power to weight ratio. Do it like that scale wings P-51 and it'd be a real winner.
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    Aircraft efficiency, a tool and list of Equivalent Flat Plate Areas of various planes

    Roncz listed the wetted areas, not flat plate. That you had to calculate yourself using the spreadsheet. Here are the wetted areas from his and Lednicers articles; VariEz 247.5 w/o gear Quickie 190.5 Solitaire 297.3 Long-Ez 325 w/o gear Catbird 398.8 VariViggen 458.2 Swift...
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    Span loading and Aspect Ratio vs glide ratio

    BH Carson popularized the idea of the "least wasteful way of wasting", ie the best bang for the buck cruise speed is around 1.32x best L/D speed. Since best L/D speed is determined by parasitic and span loading you can work backwards from a target cruise speed. The problem is doing this will...