View Poll Results: Is A Rand Robinson KR-1 A Safe Airplane?

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  • Yes

    5 71.43%
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Thread: Rand Robinson KR-1 Crashable?

  1. #1

    Rand Robinson KR-1 Crashable?

    Hello All, My name is Harley and I am 15 years old and i am interested in building a KR-1 From Plans anyone owned one?
    I have heard they are not the best flying airplanes but they seem to be a pretty good bang for the buck.....
    There have been 2 crashes at my local airport including one dumb*** performing a high speed taxi test with no wings, the airplane
    thrown aloft and smashed into the ground inverted... I am taking lessons with a former Alaska Airlines/USAF pilot who has 28000
    Hours and we are flying his RV-7..... so the point of me telling anyone listening that is so that they are aware that i have high performance
    airplane expierience..... So anyone who wants to help me decide on an airplane, give me your ideas..... THANK YOU SOOOOOOOO MUCH

  2. #2
    steveinindy's Avatar
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    Planes are generally only as safe as the pilot (or overconfident fool who thinks he's a pilot) behind the controls. That said, there are some aircraft that are better than others when it comes to crash survivability. I don't have any personal flying experience with the KR-1 so I really can't say for definite but it is definitely not one that appeals to me although it's mostly because I'm not a fan of the bubble canopy to be honest.

  3. #3

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    Steve is hedging!

    Without going into internal structure, let's define a "crash" as an off-airfield landing due to an engine out first.

    Assuming positive control, the gross weight is 750 pounds and the stall speed is 52 mph, which means the momentum is fairly low, and barring some really bad luck should be pretty high on the surviveable scale. An NTSB search bears this out.

    Next we'll look at the dreaded spin on base to final. Oof. It depends on how one strikes the ground, but the NTSB shows it related to a fatality on the search I did.
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

  4. #4
    tdm's Avatar
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    Quote Originally Posted by Frank Giger View Post
    Steve is hedging!
    Without going into internal structure, let's define a "crash" as an off-airfield landing due to an engine out first.
    I like this definition. I also like 'crash' as; "a landing in which the vertical component of flight is reduced to zero in a small amount of time sufficient to cause structural fatigue."

  5. #5
    steveinindy's Avatar
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    Assuming positive control, the gross weight is 750 pounds and the stall speed is 52 mph, which means the momentum is fairly low, and barring some really bad luck should be pretty high on the surviveable scale. An NTSB search bears this out.
    It's a very survivable event but the one big problem with the way that the NTSB categorizes injury is that someone who is permanently paralyzed from a spinal fracture, the person with a crippling head injury and the guy who breaks his ankle are all classified as "serious". For that reason, we really don't know the morbidity for these crashes. Looking at the mortality side of the statistics is fine but it gives an incomplete picture of the issue at hand.

    Next we'll look at the dreaded spin on base to final. Oof. It depends on how one strikes the ground, but the NTSB shows it related to a fatality on the search I did.
    Although given the low speeds involved, such events would be likely survivable in the face of restraints and structure design to withstand real world impacts not standards that were derived in the 1930s based off of assumptions on the tolerance of the human body to deceleration. For instance, some of the seat and restraint attachment requirements for g load are about one order of magnitude (that's a factor of ten for those on the forums who aren't fellow math geeks) below the bottom end of the limit that is generally as the "voluntary" threshold of human tolerance (meaning that someone (in this case, Dr. John Paul Stapp) was willing to allow themselves to be exposed to such levels). I'm not saying we could make all these crashes survivable but we could certainly lessen the frequency of death and lessen the severity of injury among people that would currently survive (for these types of crashes as well as the hard forced landing crashes, etc).

    It would be one of the ways to prove that general aviation is safer: make it so. Experimental aviation is more than just an FAA category. If we're going to be building something, why not do it in a way that makes all aviation safer by being a proof of concept? We have the materials, we have the skill and most of us should have the drive- if not to protect ourselves then to protect our families who fly with us and to protect our friends. If you need another reason to look at this as a worthwhile project: many of you gripe about the FAA and NTSB "meddling" but if we take it upon ourselves to do things to minimize the things that get their attention (such as the body count and bad press involved with crashes that kill people), then they have less of a reason to force us to do things that we may not appreciate. Just a thought....
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  6. #6

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    Quote Originally Posted by Harley Dickinson View Post
    .... so the point of me telling anyone listening that is so that they are aware that i have high performance
    airplane expierience..... So anyone who wants to help me decide on an airplane, give me your ideas..... THANK YOU SOOOOOOOO MUCH
    Being experienced and proficient in high performance airplanes is not going to help much when you're flying a dynamically unstable airplane.

    Lots of KR's have been built and flown so despite any shortcomings they represent a popular homebuilt from the past. No doubt the appeal is low cost. I've always thought it would be fun to build one so I say GO FOR IT! The experience would be priceless. I've always liked the idea of a KR2 with a single seat but that's just me.

  7. #7

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    Quote Originally Posted by Frank Giger View Post
    Assuming positive control, the gross weight is 750 pounds and the stall speed is 52 mph, which means the momentum is fairly low, and barring some really bad luck should be pretty high on the surviveable scale.
    There use to be a YouTube video of a KR crashing during a high speed fly by. After the dust settled, the pilot was sitting upright in a pile of splinters, dazed but otherwise ok. Not vouching for the crashworthiness of a KR because I'm sure it was more luck than anything else. Survivability involves a lot of factors.
    Last edited by martymayes; 01-14-2012 at 10:00 AM.

  8. #8

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    Quote Originally Posted by tdm View Post
    I like this definition. I also like 'crash' as; "a landing in which the vertical component of flight is reduced to zero in a small amount of time sufficient to cause structural fatigue."
    So hitting a structure while in flight would not be a 'crash'?

  9. #9
    Are you sure you didn't mean the KR-2 instead? The KR-1 is relatively rare; there are about 150 examples on the FAA registration database while there are nearly 600 KR-2s. The -2 is more popular since the -1 is a single-seater.

    I've got a database of homebuilt accidents that covers 1998 through 2010, with the data extracted from the NTSB records. There was one KR-1 accident in that 13-year period, which I believe is more a reflection on the rarity of the type than any particular safety level.

    For the KR-2s, the percentage of accidents due to pilot miscontrol is about the same as the rest of the homebuilt fleet. The KR-2 does have a higher rate of accidents due to fuel system problems... 12.5% vs. 3.5% for overall homebuilts.

    Ron Wanttaja

  10. #10

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    Quote Originally Posted by rwanttaja View Post
    For the KR-2s, the percentage of accidents due to pilot miscontrol is about the same as the rest of the homebuilt fleet. The KR-2 does have a higher rate of accidents due to fuel system problems... 12.5% vs. 3.5% for overall homebuilts.
    Any idea of the rate of gear up accidents? I thought all KR's with retract has had at least 1 gear up mishap.

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