KR> longer wings

[Larry Flesner]

At 07:19 AM 8/18/2013, you wrote:
>...when I bought the partially complete
>fuselage the original owner had already done the steps to extend the
>wings...the stub wing spars are slightly longer...the spar caps are thicker
>and the spars are longer..
+++

If you want the stock wing length with longer center section, just 
reduce the length of the outer wing panel.  I certainly wouldn't go 
any longer then the 2S wings.  The extra length of the 2S wing over 
the 2 reduces the design G rating by aprox 1 G as I recall Jeanette 
saying at one of our Gatherings.  How accurate that is I can not say.

Larry Flesner

KR> Longer Wings - please tell me if this is right

[Seth and Karen Jersild]

Hello All,

I'm going to use the 5048-45 airfoil and want to confirm whether the 
following would be the right approach if I wanted to lengthen the wings 
one foot on each side...

1) Lengthen the forward outboard spars one foot, but still taper them to 
the dimensions given for the rib at the end of the wooden spar (just 
spreading the same transition from 5048 to 5045 over a longer distance)
2) Add the one foot foam spars as suggested in the plans and taper them 
to the foam tip rib dimensions given on the 5048-45 template.

I'd use the foam extensions because if I take this approach, I won't 
have enough wood to extend the timber all the way to the "foam 
extension" tip rib.

Am I correct in understanding that this will decrease the forward sweep 
of the rear spar a little bit?  It also just occurred to me that if I 
used the foam tip rib template as given, the one foot piece at the end 
of the wing (over the foam spars) would taper at a slightly steeper 
vertical angle than the rest of the wing, since the vertical taper of 
the wood spar will become a tiny bit more shallow.  Would I have to also 
lengthen the foam extensions proportionately to continue the same 
taper?  Would any of this (decreased forward sweep and shallower taper) 
be something to be concerned about?

Sorry if these are non-issues but the spars are the first thing I'm 
going to build.  I'm no engineer and I want to be sure not to make a BIG 
mistake and screw up the airfoil dynamics.

Thanks for any input!

-Seth Jersild

KR> longer wings.....

[Brian Kraut]

Larry, I still think you have too much prop on your plane.  When I had my 
Sterba on the O-200 cut down and pitched a little less on the M-1 my climb rate 
went from about 900 FPM to about 1,300 and cruies speed increased about 8 MPH.  
I would expect you to get very similar results on the KR.  You should be 
turning up that O-200 at at least 3,100 to 3,200 RPM in cruise.

-- Original Message --
From: Larry Flesner 
Reply-To: KRnet 
List-Post: krnet@list.krnet.org
Date:  Sat, 08 Nov 2008 16:59:43 -0600
>
>I have very short wings on my heavy bird ( 20' 4" as I recall ) and
>suffer in the climb rate.  I get maybe 800 to 900 fpm on the best
>of days with a lighter fuel load.  I've considered adding to the tips
>but hate to take it down to modify and re-paint.  I seldom fly above
>3500 feet so it's not a big issue with me.  On longer trips I just do
>a cruise climb of 500 fpm at 120 mph indicated so it doesn't really
>take me long to get to 7500 or so.
>
>Larry Flesner
>
>
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KR> longer wings.....

[Jeff Scott]

Actually, I was talking about true airspeed.  It does go up with altitude until 
somewhere around 8500 feet (on my plane), where it levels off, then starts 
dropping off again as you go higher.  The altitude that happens at is dependent 
on your combination of wing, drag (including weight) and HP.  I almost never 
reference indicated air speed with regards to cruise as it always has a huge 
error at higher altitudes and I'm almost always at higher altitudes.

Jeff Scott
Los Alamos, NM


-- Larry Flesner  wrote:
Jeff,

Are you speaking of indicated airspeed here?  I would think that
the much thinner air at those altitudes would give a much lower
indicated airspeed reading than at the lower elevations.  I'm
guessing that your true airspeed would go up with altitude.
Am I missing something here?

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KR> longer wings.....

[Larry Flesner]

At 04:30 PM 11/6/2008, you wrote:
>I see my cruise speeds start to drop off above 9000' and
>see a significant impact to cruise at altitudes above 11,000'.
>Jeff Scott


Jeff,

Are you speaking of indicated airspeed here?  I would think that
the much thinner air at those altitudes would give a much lower
indicated airspeed reading than at the lower elevations.  I'm
guessing that your true airspeed would go up with altitude.
Am I missing something here?

I have very short wings on my heavy bird ( 20' 4" as I recall ) and
suffer in the climb rate.  I get maybe 800 to 900 fpm on the best
of days with a lighter fuel load.  I've considered adding to the tips
but hate to take it down to modify and re-paint.  I seldom fly above
3500 feet so it's not a big issue with me.  On longer trips I just do
a cruise climb of 500 fpm at 120 mph indicated so it doesn't really
take me long to get to 7500 or so.

Larry Flesner

KR> longer wings.....

[Jeff Scott]

I haven't normalized it for temperature, but rate of climb drops off to 200 
ft/min at roughly 14,000' at 1200# gross, or 15,500' with a lighter load.  In 
either case, it's higher than I am going to fly without O2, although better 
performance up to those altitudes would be nice.  That's with the Diehl wings 
that are a bit longer than the stock KR-2 wings.

I see my cruise speeds start to drop off above 9000' and see a significant 
impact to cruise at altitudes above 11,000'.  

Jeff Scott
N1213W
Los Alamos, NM


--  wrote:
Jeff -  have you ever determined your service ceiling?

Rick Human
N202RH
Houston, Texas


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KR> longer wings.....

[rahu...@peoplepc.com]

Jeff -  have you ever determined your service ceiling?

Rick Human
N202RH
Houston, Texas
- Original Message - 
From: "Jeff Scott" <jscott.pi...@juno.com>
To: <kr...@mylist.net>
Sent: Thursday, November 06, 2008 2:37 PM
Subject: Re: KR> longer wings.


>For sure the shorter wings are a winner down low, but if you ever want to 
>fly out west where altitude is critical, longer wings are a hands down 
>winner.  That's not to say one can't fly at higher altitudes with the 
>shorter wings, but it's sure easier with a higher aspect ratio wing and 
>more wing area.<

KR> longer wings.....

[Jeff Scott]

For sure the shorter wings are a winner down low, but if you ever want to fly 
out west where altitude is critical, longer wings are a hands down winner.  
That's not to say one can't fly at higher altitudes with the shorter wings, but 
it's sure easier with a higher aspect ratio wing and more wing area.

The GlasAir series of aircraft have an option for either the stock short wing 
tips, or bolt on wing tip extensions that add over 3 feet to the wing span.  
Two weeks ago at Copperstate, not a single GlasAir there had the short wing 
tips, which indicates how the guys that fly them feel about short vs long 
wings.  Of course this fly in was out west where they all have to fly at higher 
altitudes.

Something to keep in mind while talking about wing area.  A significant 
increase in wing area should be accompanied by more tail volume.  The small 
difference in wing area being discussed here isn't going to be critical to the 
tail volume, but it is something to contemplate or include in your building 
plan as the KRs are already a bit short on tail volume.

Jeff Scott
Los Alamos,NM


-- "Mark Langford"  wrote:

I will eventually make my wings longer.  Right now mine are only about 4" 
longer than the outer plywood template, and all of that is wing tip shaped from 
foam.  I'd rather have the improved climb, glide, and high altitude 
performance, than the slight speed improvement down low that a longer wing 
would provide.  The reason I made mine short was so I could add carbon fiber 
extensions later to see what real difference it makes.  It's just that I've 
been too busy flying it to do that, but maybe next year.  If I were you, I'd go 
ahead and make them long.  Going fast is something you do on occasion for 
bragging rights, but climbing and gliding are something you do every day, and 
under certain circumstances, can become very important...

Mark Langford, Huntsville, AL


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KR> longer wings.....

[Mark Langford]

Gary Lynn Robison wrote:

> I ass-u-med for what ever reason that the last wooden template
> was where everyone stopped and the extra 12" of wing was an option.
> And it is. (much pondering about this option)

I will eventually make my wings longer.  Right now mine are only about 4" 
longer than the outer plywood template, and all of that is wing tip shaped 
from foam.  I'd rather have the improved climb, glide, and high altitude 
performance, than the slight speed improvement down low that a longer wing 
would provide.  The reason I made mine short was so I could add carbon fiber 
extensions later to see what real difference it makes.  It's just that I've 
been too busy flying it to do that, but maybe next year.  If I were you, I'd 
go ahead and make them long.  Going fast is something you do on occasion for 
bragging rights, but climbing and gliding are something you do every day, 
and under certain circumstances, can become very important...

Mark Langford, Huntsville, AL
mail: N56ML "at" hiwaay.net
website: www.N56ML.com