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Thread: BRS installation guidelines

  1. #11

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    Quote Originally Posted by Mike Switzer View Post
    I think Eric may be right - but it shows landing nose down is a survivable option
    Lets get off that idea. Several factors pop up right away:
    *You absolutly need the best restraint system that you can install.
    *The crushable space in front of the cockpit sometimes contains a fuel tank. This will certainly rupture on impact. Count on the fuel to spray an ignitable mist on the hot engine.
    *Trees may penetrate the windshield before impact.

    On the other hand, helo pilots are taught to execute an extreme flair in the event of engine failure. Plan on going into the trees tail first. I flew with a guy that did this in Alaska in tall trees. He reported no injuries. The USAF Sikorsky was totaled.

  2. #12
    Mike Switzer's Avatar
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    Bob - my engine & fuel will be in the rear (some fuel in the wings) but nothing up front to speak of but electronics (& my feet)

    but you have a good point about the trees - the restraints will be right out of a race car so that won't be a problem

    I was considering 2 smaller chutes out the back about 5 foot out to clear the prop arc

  3. #13
    Dana's Avatar
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    Quote Originally Posted by Mike Switzer View Post
    Bob - my engine & fuel will be in the rear (some fuel in the wings) but nothing up front to speak of but electronics (& my feet)
    Consider whether you really want to hit nose down with the engine and fuel behind/above you... and hitting feet first is asking for broken legs or shattered ankles...

  4. #14
    Mike Switzer's Avatar
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    Everything is a compromise. I wouldn't even consider installing a chute if it was a proven design, but I'm scared of what will happen if something funky happens during the flight testing & I get into a stall/spin situation.

    Maybe I should just temporarily install one in the baggage area & remove it if it flies OK.

  5. #15
    rosiejerryrosie's Avatar
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    My MiniMax had the BRS installed externally - on the belly just behind the main landing gear. The riser straps were anchored to the frame just behind the pilot and were enclosed in a 'quick rip off' covering on the outside of the fuselage as they led to the chute mounted under the airplane. It is the white dot you can see under the airplane.... Name:  Low take off .jpg
Views: 498
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    Cheers,
    Jerry

    NC22375
    65LA out of 07N Pennsylvania

  6. #16
    Mike Switzer's Avatar
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    Jerry, how does that work if it is mounted on the bottom? Do the straps run around one side of the fuselage & up to the top so you land right side up?

  7. #17

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    I wanted to stay out of this. But I dont want any body to get hurt. I admit to some formal training in crash survival investigation and design. Arizona State Univ.

    I don't know the BRS that well, but some figures for the US T-10 chute: 34 ft dia, max deployment 170 MPH, rate of desc 22 f/sec(about 22MPH)
    Human tolerances (Varies): Gloc=4 to 6Gz (vert axis)
    Injury threshold: +17Gx (Eyeballs in)
    -12Gx (eyeballs out) See Col Stapp 1954 or so.
    +25Gz (Eyeballs down)
    -15Gz (Eyeballs up)
    *You should consider ramification of an assymetric chute deployment. Do model testing.
    *You will have descent angle of 90deg. Need a crushable structure ahead of cockpit. 3-4 feet. also crashworthy fus tank.
    *All said, best survival option is land horiz.

    About that Sonex that deploys out the belly and descends inverted. Someone is yanking our chain. No overhead structure, Real bad if landed in boulders or water. Sad songs and slow walks follow.

    I dug out my class "stuff" and though my "tricky-nometry" is rusty I am available to follow you through best I can on your plans. Bottom line: Land on the wheels, have some styerfoam or like that under the seat, and suspend under a 3 or 4 point suspension. Good luck.
    P.S. Jerry's rig suspends the plane in this manner. I would ride is M.M down any day.

    Bob

  8. #18

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    One last thought Mike. If you could mount the chute in the nose, and desc tail first, you have all that structure behind you to sacrifice while eating up energy. Your body is oriented to absorbe more G.

    Bob

  9. #19
    Mike Switzer's Avatar
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    Quote Originally Posted by Bob Dingley View Post
    One last thought Mike. If you could mount the chute in the nose, and desc tail first, you have all that structure behind you to sacrifice while eating up energy. Your body is oriented to absorbe more G.

    Bob
    That would actually be the easiest place to mount it as there will be a mostly empty (probably fiberglass) nosecone in front of the steel tube fuselage. Anywhere else in the fuselage & it gets that rocket too close to things i really don't want it close to, and being a tandem design there won't be a whole lot of available space.

  10. #20
    Matt Gonitzke's Avatar
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    Quote Originally Posted by Bob Dingley View Post
    One last thought Mike. If you could mount the chute in the nose, and desc tail first, you have all that structure behind you to sacrifice while eating up energy. Your body is oriented to absorbe more G.

    Bob
    I had just thought of the same thing. One issue with that might be ensuring that the parachute clears the aircraft and doesn't get entangled in it when being deployed from the front.

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