In reference to Dr Feng's safety concerns here is a lot to consider. Keep in
mind like Larry said that this is the first known wing failure of a KR in 30
years. Let's see, Piper Cherokee lost a wing on a checkride in Florida two
years ago. Cessna 400 series and Beech 18 series both had to have straps added
to them due to multiple spar failures. This is very rare but it dues happen to
both certified and experimentals. Putting a chute on an airplane is possible
though isn't as simple as it might seem. I have worked with Velocity for a long
time and some customers have requested chutes but when it was looked at closely
there are many factors to consider. Speed was the main concern in the Velocity.
Engineering attach points that will stand up to the deceleration loads imposed
when the chute inflates at 200 mph.
The KR has similar concerns plus additional weight that needs to be of concern.
Let's start with the weight of a KR. Remember that the original KR2 weight just
480 lbs with a gross weight of just 900 lbs. If you increase the weight of the
airplane too much you have to change the spar design to carry the load. Wearing
a backpack chute is probably safer than having a chute added to the KR.
Before we make assumptions about the strength which has never been questioned
up to this point we need to find out exactly what happened and that may or may
not be possible. Was it rot, flutter, overstressed, additional holes drilled in
the spar for various reasons etc? How had the airplane been flown? How much
stress had been put on it. Go out in your average Cessna 150 and dive it to 200
mph and pull back hard on it like many KR's do routinely and tell me the
result. The result is a failed wing long before it gets to that speed. Be
carefull about adding weight to the design. Remember the spars were only
designed to carry a certain amount. Bottom line is this is an experimental
airplane that you as the builder can add anything you want.
You are right in that there are a lot of deaths in experimentals and even one
is too many. Though finding the correct fix for a homebuilt is a lot harder
because unlike certificated aircraft there probably aren't two KR's built
exactly alike and there probably isn't any built exactly to the plans. To find
the correct fix also means that you have to determine the exact cause of the
failure.
The best insurance for reducing accidents is careful attention to maintenance
and safe flying.
Victor Taylor CFII, KR N47MG
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