I have had 2 KR's and test flew 3 others here in Texas and Have never heard of 
a tork roll in one. 1 has a EJ22 150 hp. My first one started out with a 1835 
and finished with a 0-200. I have seen a vidio of a KR do a full power stall, 
but had not heard of one do a tork roll. The planes that did that where running 
a lot of power. More than we could ever put on a little KR
 

--- On Thu, 7/9/09, laser...@juno.com <laser...@juno.com> wrote:


From: laser...@juno.com <laser...@juno.com>
Subject: KR> Suburu engines - something to consider
To: kr...@mylist.net
List-Post: krnet@list.krnet.org
Date: Thursday, July 9, 2009, 1:18 AM


Probably the biggest reason to avoid higher-powered engines in KR's is
the problem with immediate and fatal torque rolls once the wheels leave
the runway.  Using a PSRU with a Suburu and its extra torque this
tendency would even be worse.  

When KR's just had VW's, torque rolls after takeoff were not a serious
problem, but once the horsepower started to go up, the fatal torque rolls
started.  Among those first fatalities was Homer Didit of Mena, Arkansas
who put that R-985 in his KR-2.  He only made the one flight and augered
in on takeoff.

And what about that fellow with the turbine KR?  I haven't seen or heard
about it for quite some time now.  Torque roll on takeoff?  

I never see this phennomenon discussed on these forums.  Is it something
we just don't like to talk about?  The 300 lb. gorilla sitting in the
corner?  I think it's time people gave this deadly KR quirk some
attention so that new pilots won't be caught unawares when they push that
throttle forward.   

I'm sure the Corvair people will correct me if I'm wrong, but seems like
there have been a flock of  KR's with Corvair six cylinder engines that
torque-rolled in - pulling it off too soon with full throttle. 
Torque-roll.  Boom.  Smoke.  There's just too much temptation to firewall
the throttle and try and show off with a vertical climb when you have all
that power available.  Remember, these planes are made of styrofoam. 
Hanging a huge engine on the front is just asking for trouble.           


What got me started on this train of throught was that I've always
wondered why one of my tires wears out before the other one.  Landing on
one tire more than the other would explain it, except at my home field
the normal crosswind would favor wearing out the tire on the upwind side,
not the one that actually wears.  The difference is not great, but it's
noticable and consistent. 

It wasn't until I came across this piece by John Deakin in his column
Pelican's Perch on Avweb that I realized what is happening.  

"But in something like the Bearcat, the power is much higher, the torque
is correspondingly greater, and the wings are shorter, giving less
leverage. I assure you, the roll is there, and it's very noticeable. Left
tires wear out much sooner on the Bear."

Since our engines mostly turn to the left, our tires wear out on the
other side - the right side.  Even with our puny little engines (compared
to the warbirds the article is about), there is enough of a difference
over time to wear out the right tire more than the left one.  

And so another mystery is solved.    


Mike


Deakin's articles are really a wealth of good info on many aviation
topics, for those who haven't yet come across him.

http://www.avweb.com/news/pelican/182146-1.html
  
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