Read you Dec 11, 2005 note on hershey bar wings, why would you put a
hershey bar wing on anything, especially a LSA airplane? That would put
the increased lift out at the wing tip where you don't want it. I have
looked at redesigning the KR-2, of course it would not be a KR-2 anymore,
but it would be easy to increase the span of the center section and even
the chord to get the increased area that you wanted and use a thicker
airfoil (21 percent, we tested one at the low turbulence tunnel at NASA's
LRC in the 80's) to make it stronger and reduce the weight of the spar.
Other weight reduction could be made in much of the structure. I don't
think it would be much of a problem.
Jim
On Sat, 11 Mar 2006 19:52:10 -0500 "Brian Kraut" <brian.kr...@engalt.com>
writes:
> During my 40 hour test flying on the Mustang I got bored to tears
> and
> decided to test the windmilling or not theory. I was surprised to
> find that
> on that plane I had a better glide ratio with the prop windmilling
> than with
> it stopped. With my particular prop and engine combination the prop
> would
> windmill until I slowed to about 90. It would not start spinning
> again
> until I speed up to about 140 so I had a pretty good range where I
> could
> choose a windmilling or stopped prop. I actually did something like
> 5-10%
> better glide with it still windmilling.
>
> Keep in mind that this was one particular airplane, prop, and
> engine
> combination and I don't doubt that many, if not most, other
> combinations
> will glide further with the prop stopped. With a lower pitch prop
> and a
> higher compression engine you also might not be able to keep it
> windmilling
> at anywhere near your best glide speed. It all boils down to if you
> want to
> know try it yourself in your plane. Now that I have cut two inches
> off the
> prop and had it pitched 4" lower I will try again and see if I still
> get the
> same results.
>
> Oh, and don't try this experiment if you don't have a mixture
> control. Shut
> your engine with the mag switch and then turn it back on with the
> prop
> windmilling and you are going to get the backfire from hell.
>
> Brian Kraut
> Engineering Alternatives, Inc.
> www.engalt.com
>
> -----Original Message-----
> From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On
> Behalf Of Mark Langford
> Sent: Saturday, March 11, 2006 9:15 AM
> To: KRnet
> Subject: KR> windmiling props
>
>
> Bobby wrote:
>
> >When the engine quit for real, it amazed me how fast it
> > came down with a prop stopped.
>
> That's interesting, because conventional wisdom is that planes glide
> better
> with the prop stopped than with it idling or windmilling, so I've
> always
> used my idling glide rates as "worst case". See
> http://selair.selkirk.bc.ca/aerodynamics1/Multi/Page2.html#Windmilling
> for
> more on drag produced by windmilling props, or idling props. The
> small
> diameter props and high compression engines that we use on KRs
> won't
> windmill anyway, so engine-off glide should be better than idling
> glide. I
> haven't proven that yet, but once it gets warmer and shock cooling
> isn't as
> bad, I plan to test that one too.
>
> Anybody want to give me a speech on shock cooling?
>
> Mark Langford, Harvest, AL
> see homebuilt airplane at http://www.N56ML.com
> email to N56ML "at" hiwaay.net
>
>
> _______________________________________
> Search the KRnet Archives at
> http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>
>
>
> _______________________________________
> Search the KRnet Archives at
> http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>
>
