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  1. Mar 26, 2019 #21

    Scheny

    Scheny

    Scheny

    Well-Known Member

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    I don't think they actually did modify it a lot at all... If you look at the plans, they just put it in where it would fit. That's why the exhaust is where the propshaft would be and also why they put it at an angle.

    As for the safety: I am not aware either of any plane this size having safety (JSX pretends to be safe as they offer an optional BRS...). This is why our Beast One is designed as a BD-5J alternative with good stall characteristics, low landing speed, good longitudinal stability, a safety cell and a BRS.

    The safety cell is designed for 30G, while the nose incorporates a 2 feet crash attenuator design followed by a one feet severity reduction element (damper+antisnag) all derived from formula one by our chassis experts (final layout will start in September).

    As for the "good flight behaviour" of the BD-5: Longitudinal stability is below any standard while landing speed is rather high. If the engine fails it will nose up, which is fatal right after start. Some BD-5 pilots say "it is absolutely no problem, you got a full sencond to react", but decide on your own...

    You can see it with the Boeing 737 Max. There are only professional pilots flying them and they had apprximately 40 seconds to react to MCAS and still 2 out of 2 crashed... So, of course if you specifically train for the bad behaviour of the BD-5, it can be a nice plane with cool performance (until it kills you).

    With a safety record of almost half of the built planes already crashed (some statistics say only a third), it reminds me of the Starfighter where they interviewed a former pilot who said "you just get in and tell yourself you are better than the others, this will not happen to you".
     
  2. Mar 26, 2019 #22

    kent Ashton

    kent Ashton

    kent Ashton

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    Do you have $50K for the jet engine and $30K to build the airplane around it? I just sold my BD-5 prop kit but a fellow who knows about the jets told me the folks who know how to build and install the jets want to build the whole thing and don't want to take a half-finished, poorly-build project and try to convert it to a jet. I asked a jet owner for advice or plans and he said "get it done professionally". This is probably good advice because many people who build a BD-5 do not even have the skill, experience, or machine shop required to build a nice, straight, clean airplane. I certainly went through that with mine back in the day. When it was finally on-the-gear, I said, "this is not nice enough to justify a $60K jet engine installation". If you can provide one of the professional builders with a mostly complete kit and $75K+ (a very rough estimate), I believe it is very doable--not much more complicated than increasing the fuel capacity and installing the intakes, engine, and tailpipe. The pros know how to do it but they are not interested in sharing their hard-won knowledge. There is reason why we don't see 4000 jet BD-5s.
     
  3. Mar 26, 2019 #23

    kent Ashton

    kent Ashton

    kent Ashton

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    This one of the most complete photo documentations of a BD-5 build I've seen. It will give you a good idea what's involved.
    http://s1192.photobucket.com/user/amnpilot/library/?sort=3&page=1
    It all looks pretty doable but remember that what get in the kit are skins, preformed wing ribs, spars and lots of raw materials. Yes, I am oversimplifying but it ain't like a modern Van's RV kit. A scratch-built Long-ez is easier to build.
     
    MadRocketScientist likes this.

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