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av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Thu Jan 15, 2009 10:35 pm Post subject: 26 foot Clipped Wing Kitfox

Hi Gang,



I'm working on a second Kitfox project (model IV 912ul with IFA IVO) and am seriously thinking about making removable wing extensions, but with a shorter span than the Speedster.  I have it all pretty much figured out now, so it is just a question of whether or not to do it.  Anyone have any opinions on this?  Also, I would love to see some construction photos of slide in wing extensions if anyone has done a speedster conversion from the long wing.



Oh yeah, I'm basing my rationale for doing this on what Avid did back in the early days when they took their 29+ foot Avid STOL wing off their airplane and made a new semi-symmetrical airfoil with only a 24 foot span.  That was pretty short in most peoples opinion, but overall still worked out ok.  So I would think a 26 foot Kitfox wing would still provide reasonable performance.  I would realistically anticipate a 3-400 fpm drop in climb, but a 15-20 mph increase in cruise over the standard wing.  At least that's my goal based on some initial calculations. 



Worse case scenario is that I slide the wing extensions back on because it didn't work out like I hoped it would.



Paul S

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Fri Jan 16, 2009 1:37 am Post subject: 26 foot Clipped Wing Kitfox

On Thu, January 15, 2009 10:35 pm, av8rps wrote:

 	  Quote: 	
		   



 ...... and made a new

 semi-symmetrical airfoil with only a 24 foot span.  That was pretty short in most

 peoples opinion, but overall still worked out ok.  So I would think a 26 foot Kitfox

 wing would still provide reasonable performance.  I would realistically anticipate a

 3-400 fpm drop in climb, but a 15-20 mph increase in cruise over the standard wing.

 At least that's my goal based on some initial calculations.


	


Here's what you're going to get for sure.



1) Higher wing loading per unit area. This will make it a little more resistant to

being blown over when parked and it will provide a little smoother ride in rough air.



2) Decidedly faster roll rate. This is something people desire for doing aerobatics.



3) Substantially increased stall speed and hence landing approach speed and lengthened

landing rollout and distance to liftoff.



I would not expect the maximum rate of climb to be drastically reduced. The max climb

rate speed and the max angle speeds will change, both increasing with a shorter

wingspan.  I would not expect any significant increase in cruise speed and in fact it

might be lower.



You mention calculations. I'd like to see them. Especially how you arrived at a higher

cruise speed for the same power setting.



You'll likely notice a bit of nose high attitude compared to the same loading

conditions with longer wings.



I would not do this modification unless it were specifically for increased roll rate

that you would want for aerobatics. Of course the bird would fit in a smaller hangar,

ride a little smoother in bumpy air and be just a little less likely to act like a

kite when tied down.



--

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Fri Jan 16, 2009 8:37 am Post subject: 26 foot Clipped Wing Kitfox

At 10:35 PM 1/15/2009, you wrote:

 	  Quote: 	
		  Anyone have any opinions on this?  Also, I would love to see some 

construction photos of slide in wing extensions if anyone has done a 

speedster conversion from the long wing.


	


Paul,

         I think it is a GREAT idea. But if you're going to go that 

short, you might want to consider getting rid of the struts and 

building a cantilever wing. That will save you a lot of drag. Or if 

you go with a structural leading edge "D" section you could eliminate 

one strut and dramatically increase the utility of vortex generators. 

(They don't generally do much on our stock airfoil.) Or if you go 

with the stock wing you could shorten the struts proportionally. That 

would save some drag.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

gary.algate(at)sandvik.co
Guest

Posted: Fri Jan 16, 2009 8:53 pm Post subject: 26 foot Clipped Wing Kitfox

I have a set of wing extensions for my Classic 4. It has most of the speedster mods and I never use the extensions. 

If you wanted to experiment with them I would be prepared to sell them. 

They are in n excellent cond if you are interested 

Gary 

 Gary Algate

 Classic 4 Ja 2200

 Office Phone: +61 8 8276 7655

 This e-mail is confidential and it is intended only for the addressees. Any review, dissemination, distribution, or copying of this message by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error, kindly notify us immediately by telephone or e-mail and delete the message from your system. The sender does not accept liability for any errors or omissions in the contents of this message which may arise as a result of the e-mail transmission.

 “This year, instead of sending you a Christmas card in the mail, we have made a contribution to [url=Arial]UNICEF Australia[/url]. We wish you a safe and happy Christmas". 

"Paul Franz - Merlin GT" <paul(at)eucleides.com> 

Sent by: owner-kitfox-list-server(at)matronics.com 

16/01/2009 07:47 PM 

Please respond to

 kitfox-list(at)matronics.com     To

 kitfox-list(at)matronics.com   cc

    Subject

 Re: 26 foot Clipped Wing Kitfox 

--> Kitfox-List message posted by: "Paul Franz - Merlin GT" <paul(at)eucleides.com>

 On Thu, January 15, 2009 10:35 pm, av8rps wrote:

 > --> Kitfox-List message posted by: "av8rps" <paul676(at)tds.net>

 >

 > ...... and made a new

 > semi-symmetrical airfoil with only a 24 foot span.  That was pretty short in most

 > peoples opinion, but overall still worked out ok.  So I would think a 26 foot Kitfox

 > wing would still provide reasonable performance.  I would realistically anticipate a

 > 3-400 fpm drop in climb, but a 15-20 mph increase in cruise over the standard wing.

 > At least that's my goal based on some initial calculations.

 Here's what you're going to get for sure.

 1) Higher wing loading per unit area. This will make it a little more resistant to

 being blown over when parked and it will provide a little smoother ride in rough air.

 2) Decidedly faster roll rate. This is something people desire for doing aerobatics.

 3) Substantially increased stall speed and hence landing approach speed and lengthened

 landing rollout and distance to liftoff.

 I would not expect the maximum rate of climb to be drastically reduced. The max climb

 rate speed and the max angle speeds will change, both increasing with a shorter

 wingspan.  I would not expect any significant increase in cruise speed and in fact it

 might be lower.

 You mention calculations. I'd like to see them. Especially how you arrived at a higher

 cruise speed for the same power setting.

 You'll likely notice a bit of nose high attitude compared to the same loading

 conditions with longer wings.

 I would not do this modification unless it were specifically for increased roll rate

 that you would want for aerobatics. Of course the bird would fit in a smaller hangar,

 ride a little smoother in bumpy air and be just a little less likely to act like a

 kite when tied down.

 --

 Paul A. Franz

 Registration/Aircraft - N14UW/Merlin GT

 Engine/Prop - Rotax 914/NSI CAP

 Bellevue WA

 425.241.1618 Cell

av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Sun Jan 18, 2009 7:18 pm Post subject: Re: 26 foot Clipped Wing Kitfox

Paul,



Thanks for your input on my clipped wing idea.  I have to admit my calculations are very basic, derived after going through a few books on aerodynamics, and then making some comparisons to aircraft like the Swick Clip  Wing Taylorcraft, Clip Wing Monocoupe, etc.  I do know at one time Kitfox themselves had considered doing this same mod, but I heard through the grapevine later that they had concerns about owners overspeeding the airframe by using the larger hp 912 engines, and/or overspeeding during acro.  That made sense to me, but I really think if I am cautious about how the airplane gets used with the shorter wing, things should be ok.   And if the experiment proves to not do what I think it should, then I'll just slide my wing tip extensions back in and go back to a normal wingspan.



Paul



[quote="Paul A. Franz, P.E."]On Thu, January 15, 2009 10:35 pm, av8rps wrote:

 	  Quote: 	
		   



 I would not do this modification unless it were specifically for increased roll rate

that you would want for aerobatics. Of course the bird would fit in a smaller hangar,

ride a little smoother in bumpy air and be just a little less likely to act like a

kite when tied down.



--

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Sun Jan 18, 2009 7:24 pm Post subject: Re: 26 foot Clipped Wing Kitfox

Guy,



I agree that building a new design wing would be more practical for overall speed, but I'm not quite wanting to change the Kitfox quite that much.  My goal is to see how efficient I can make the existing wing design with the airframe and 80 hp 912.  And above all things, I just want to find out what it will do for the airplane, as done by just cutting down the existing wing it is a pretty easy thing to do.  I just have to cut down the flaperons and make the wing slide in extensions should I want to go back to the standard wing.  



But thanks for the ideas. Heck, thinking about all this stuff is the fun part!



Paul  

[/quote]

Paul,

         I think it is a GREAT idea. But if you're going to go that 

short, you might want to consider getting rid of the struts and 

building a cantilever wing. That will save you a lot of drag. Or if 

you go with a structural leading edge "D" section you could eliminate 

one strut and dramatically increase the utility of vortex generators. 

(They don't generally do much on our stock airfoil.) Or if you go 

with the stock wing you could shorten the struts proportionally. That 

would save some drag.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.[/quote]

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Mon Jan 19, 2009 3:03 pm Post subject: 26 foot Clipped Wing Kitfox

At 07:24 PM 1/18/2009, you wrote:

 	  Quote: 	
		  I just have to cut down the flaperons and make the wing slide in 

extensions should I want to go back to the standard wing.


	


Paul,

         I'd think hard about figuring out how to get the flaperons 

back. (Maybe a slide-in flaperon extension too.) I'd hate to fly a 

long-wing or Speedster with "inboard" flaperons.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Wed Jan 21, 2009 7:23 pm Post subject: Re: 26 foot Clipped Wing Kitfox

Guy,



I'm not following what you mean. What I meant about the flaperon change was that in order to have a 26 foot wingspan Kitfox I will need to cut off a whole bay's worth of flaperon so it matches up with the shorter span wing.  I do have a spare set of flaperons laying around that I can cut down for this use, but would really prefer to be able to just slide on a flaperon extension like I would the wing extension whenver I want a long full span wing.  It would be much easier and quicker to attach the flaperon extension (if possible) rather than having to change both flaperons back and forth whenever the wing extensions are removed or installed.  



I'm wide open for any suggestions or ideas for an easily removed and installed flaperon extension?



Paul 

 	  Quote: 	
		  Paul,  I'd think hard about figuring out how to get the flaperons 

back. (Maybe a slide-in flaperon extension too.) I'd hate to fly a 

long-wing or Speedster with "inboard" flaperons.

Guy Buchanan

San Diego, CA

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Wed Jan 21, 2009 8:16 pm Post subject: 26 foot Clipped Wing Kitfox

At 07:23 PM 1/21/2009, you wrote:

 	  Quote: 	
		  I do have a spare set of flaperons laying around that I can cut down 

for this use, but would really prefer to be able to just slide on a 

flaperon extension like I would the wing extension whenver I want a 

long full span wing.  It would be much easier and quicker to attach 

the flaperon extension (if possible) rather than having to change 

both flaperons back and forth whenever the wing extensions are 

removed or installed.


	


         That's what I meant; simply that you wouldn't want to 

permanently shorten the flaperon. As to how to sleeve it, that's 

another matter, but I think a short fiberglass sleeve with recessed 

blind nuts allowing countersunk screws through the two flaperon 

pieces would be sufficient. You could lay the fiberglass sleeve up 

inside the cut flaperon. Don't worry about a good fit at the trailing 

edge. Indeed I'd bring it around in a tubular fashion a couple inches 

shy of the trailing edge.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Wed Jan 21, 2009 8:31 pm Post subject: Re: 26 foot Clipped Wing Kitfox

A buddy here has an extended speed wing avid MK IV.  The flaperon extension is on the inboard end and is just a tube that plugs into the flaperon spar and extends the spar into the fuse for the control hook up.  You end up with a shorter flaperon, but his plane fly's just fine and still has a very sporty roll rate.  The flaperon is just moved to the outboard panel when you put the extension on so you don't end up with a very sluggish roll rate.  I can get a pic of it in the next day or two if it will help you visualize what I am talking about.

_________________
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 (147 hrs and counting on the rebuild)
IVO IFA
Full Lotus 1450
#1 snake oil salesman since 1-22-2009

I would rather die trying to live, than to live trying not to die....

dgolden(at)golden-consult
Guest

Posted: Thu Jan 22, 2009 7:22 am Post subject: 26 foot Clipped Wing Kitfox

av8rps wrote:

 	  Quote: 	

 Guy,

 I'm not following what you mean. What I meant about the flaperon change was that in order to have a 26 foot wingspan Kitfox I will need to cut off a whole bay's worth of flaperon so it matches up with the shorter span wing.  I do have a spare set of flaperons laying around that I can cut down for this use, but would really prefer to be able to just slide on a flaperon extension like I would the wing extension whenver I want a long full span wing.  It would be much easier and quicker to attach the flaperon extension (if possible) rather than having to change both flaperons back and forth whenever the wing extensions are removed or installed.  

 I'm wide open for any suggestions or ideas for an easily removed and installed flaperon extension?

 Paul 

Since you're dealing with a control surface, aren't you concerned about

the possibility of flutter? They changed the design of the mass balance

for the Speedster because of this.

 	  Quote: 	
		  > Paul,  I'd think hard about figuring out how to get the flaperons 

> back. (Maybe a slide-in flaperon extension too.) I'd hate to fly a 

> long-wing or Speedster with "inboard" flaperons.

> Guy Buchanan

> San Diego, CA

Dennis M IV Speedster (Someday)

-- 

Dennis Golden

Golden Consulting Services, Inc.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Thu Jan 22, 2009 8:52 am Post subject: Re: 26 foot Clipped Wing Kitfox

There is very little to be gained by making your wing that short.  You will increase your roll rate, and get a smoother ride in turbulence, maybe have a bit better handling in wind, but thats about it.  The price you pay for this will be very high.  



Your imagined increase in cruise speed will most likely NOT happen.   The wingspan of an airplane does not increase the drag as much as you think and when you shorten it you will not see an increase in speed.  What you will likely do is actually slow down your airplane by INCREASING induced drag.  With a very short wing, the angle of attack to maintain level flight can become so high that drag is greatly increased with a shorter wing.  



You will decrease your climb rate significantly.   And more importantly you will decrease you safety.  With much higher speeds needed for approach and landing, your options with an engine out will be much worse than with a longer wing in the event of an engine disappointment.  You will also reduce the number of fields you can fly in and out of safely, hope you don't like short grass fields.



Titan added 4 feet to the length of the wingspan in their Titan Tornado Super Sport with NO loss of speed, got an increase in climb, and decrease of stall and approach speeds.   It is a very common misconception that decreasing wingspan of an airplane will make it faster, if it were that easy everyone would be doing it, including most of airplane manufacturers.   All this has been done, and Kitfox has come up with about the best balance of high speed cruise and good climb rate, and slow speed performance with the wingspan they have.

So if your idea is to go out and do aerobatics, and fly in huge winds and turbulence, your short wing will probably be a good thing.   If you think you are going to cruise faster, and have an airplane that has good climb, and any kind of performance at altitude, you are in for a very big disappointment.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Thu Jan 22, 2009 9:36 am Post subject: Re: 26 foot Clipped Wing Kitfox

yeah  and short wing pipers don't fly either right????  The pacer clan of pipers has alot shorter wing than a cub or 12 etc.  They fly fine, in fact, I am about an hour away from rolling one out the the hangar to fly a guy up to pick up another one.  People say the pacer is a hand full and tricky to fly... this all brought on by people that don't get out and fly much.  I can get it to fly within 5 MPH of my avid on landing and take off, yet cruise much faster.



Paul, experiment away, you can plug the wing back in if it does not work, if it does GREAT.  You know the potential consequences of shortening the wing (faster ground speed on TO/ landing are a given), the rest is speculation and as of yet opinion.... and we all know that each of us has one, and what it compares to lol.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Thu Jan 22, 2009 10:30 am Post subject: Re: 26 foot Clipped Wing Kitfox

 	  akflyer wrote: 	
		  



yeah  and short wing pipers don't fly either right????  The pacer clan of pipers has alot shorter wing than a cub or 12 etc.  They fly fine, in fact.



	




You are very wrong about that AKFlyer, the short wing Pipers have a horrible reputation, and rightfully so.  There is a really good reason manufacturers of modern airplanes have not imitated these short winged Pipers, and why the short winged pipers have not been produced in many many years and have never been copied ( Unlike the Piper Cub ).  So despite your " Flawed Reasoning " and somewhat appealing an nostalgic post relating to old pipers, what you say is just bad information.   I would hope most people here are smart enough to realize bad information even when it is presented by some slick, smoothing talking, snake oil salesman.



Given aerodynamic information available these days, it is a really bad idea to clip the wings that short.  Just look at the wingspans of most modern Light Sport Aircraft today, their wings have a pretty high aspect ratio, there is a very good reason for that.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Thu Jan 22, 2009 5:56 pm Post subject: Re: 26 foot Clipped Wing Kitfox

Wow. Posts like this are the reason I stopped reading this forum. I poke in once in three months and I'm not disappointed. Glad to know I'm not missing much. Thanks!



 	  Quote: 	
		  You are very wrong about that AKFlyer, the short wing Pipers have a horrible reputation, and rightfully so. There is a really good reason manufacturers of modern airplanes have not imitated these short winged Pipers, and why the short winged pipers have not been produced in many many years and have never been copied ( Unlike the Piper Cub ). So despite your " Flawed Reasoning " and somewhat appealing an nostalgic post relating to old pipers, what you say is just bad information. I would hope most people here are smart enough to realize bad information even when it is presented by some slick, smoothing talking, snake oil salesman.



Given aerodynamic information available these days, it is a really bad idea to clip the wings that short. Just look at the wingspans of most modern Light Sport Aircraft today, their wings have a pretty high aspect ratio, there is a very good reason for that.

_________________
Luis Rodriguez
Model IV 1200
Rotax 912UL
Flying Weekly
Laurens, SC (34A)

gary.algate(at)sandvik.co
Guest

Posted: Thu Jan 22, 2009 6:19 pm Post subject: 26 foot Clipped Wing Kitfox

I wish we had some way of just removing malicious content like "I would hope most people here are smart enough to realize bad information even when it is presented by some slick, smoothing talking, snake oil salesman."  

 

What is it with these people. 

 

Most of the list  seems to be intelligent, kind and helpful and then we get some genuinely rude members that somehow get through the screening process. 

 

I think if you don't agree with a comment it's your prerogative to respond with a different view but there's no excuse for personally attacking another list member. 

 

It's a great forum "normally"

  

Gary 



 Gary Algate

 Classic 4 Jab 2200

 Office Phone: +61 8 8276 7655

 

 

 This e-mail is confidential and it is intended only for the addressees. Any review, dissemination, distribution, or copying of this message by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error, kindly notify us immediately by telephone or e-mail and delete the message from your system. The sender does not accept liability for any errors or omissions in the contents of this message which may arise as a result of the e-mail transmission.

 “This year, instead of sending you a Christmas card in the mail, we have made a contribution to [url=Arial]UNICEF Australia[/url]. We wish you a safe and happy Christmas". 

 

 

 

    

 

 

 

"wingnut" <wingnut(at)spamarrest.com> 

Sent by: owner-kitfox-list-server(at)matronics.com 

23/01/2009 12:34 PM 

Please respond to

 kitfox-list(at)matronics.com     To

 kitfox-list(at)matronics.com   cc

    Subject

 Re: 26 foot Clipped Wing Kitfox 

     

 

 

 

--> Kitfox-List message posted by: "wingnut" <wingnut(at)spamarrest.com>

 

 Wow. Posts like this are the reason I stopped reading this forum. I poke in once in three months and I'm not disappointed. Glad to know I'm not missing much. Thanks!

 

 

 > You are very wrong about that AKFlyer, the short wing Pipers have a horrible reputation, and rightfully so. There is a really good reason manufacturers of modern airplanes have not imitated these short winged Pipers, and why the short winged pipers have not been produced in many many years and have never been copied ( Unlike the Piper Cub ). So despite your " Flawed Reasoning " and somewhat appealing an nostalgic post relating to old pipers, what you say is just bad information. I would hope most people here are smart enough to realize bad information even when it is presented by some slick, smoothing talking, snake oil salesman.

 > 

 > Given aerodynamic information available these days, it is a really bad idea to clip the wings that short. Just look at the wingspans of most modern Light Sport Aircraft today, their wings have a pretty high aspect ratio, there is a very good reason for that. 

 

 

 --------

 Luis Rodriguez

 Model IV 1200

 Rotax 912UL

 Flying Weekly

 Laurens, SC (34A)

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=226271#226271

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu Jan 22, 2009 6:30 pm Post subject: 26 foot Clipped Wing Kitfox

Hey, we've missed you Luis....it's not like this all the time...why,  

just last week we were all enjoying talking about tailwheels, or  

maybe that was just me enjoying it, while some others suffered. : )



If you're still tuned in, some of us are also "flying weekly" if not  

daily. Why not tell us about some of your flying adventures...that  

seems to be the hot topic.

Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 600.2 hrs

Sensenich 62x46

Electroair direct-fire ignition system

New skis done and flying

do not archive



On Jan 22, 2009, at 8:56 PM, wingnut wrote:



 	  Quote: 	
		   



 Wow. Posts like this are the reason I stopped reading this forum. I  

 poke in once in three months and I'm not disappointed. Glad to know  

 I'm not missing much. Thanks!

> You are very wrong about that AKFlyer, the short wing Pipers have  

> a horrible reputation, and rightfully so. There is a really good  

> reason manufacturers of modern airplanes have not imitated these  

> short winged Pipers, and why the short winged pipers have not been  

> produced in many many years and have never been copied ( Unlike  

> the Piper Cub ). So despite your " Flawed Reasoning " and somewhat  

> appealing an nostalgic post relating to old pipers, what you say  

> is just bad information. I would hope most people here are smart  

> enough to realize bad information even when it is presented by  

> some slick, smoothing talking, snake oil salesman.

>

> Given aerodynamic information available these days, it is a really  

> bad idea to clip the wings that short. Just look at the wingspans  

> of most modern Light Sport Aircraft today, their wings have a  

> pretty high aspect ratio, there is a very good reason for that.

 --------

 Luis Rodriguez

 Model IV 1200

 Rotax 912UL

 Flying Weekly

 Laurens, SC (34A)





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 26271#226271

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

gary.algate(at)sandvik.co
Guest

Posted: Thu Jan 22, 2009 6:44 pm Post subject: 26 foot Clipped Wing Kitfox

Love that sense of humour! Why are you still up?

 

 Gary Algate

 SMC, Exploration

 Office Phone: +61 8 8276 7655

 

 

 This e-mail is confidential and it is intended only for the addressees. Any review, dissemination, distribution, or copying of this message by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error, kindly notify us immediately by telephone or e-mail and delete the message from your system. The sender does not accept liability for any errors or omissions in the contents of this message which may arise as a result of the e-mail transmission.

 “This year, instead of sending you a Christmas card in the mail, we have made a contribution to [url=Arial]UNICEF Australia[/url]. We wish you a safe and happy Christmas". 

 

 

 

    

 

 

 

Lynn Matteson <lynnmatt(at)jps.net> 

Sent by: owner-kitfox-list-server(at)matronics.com 

23/01/2009 01:07 PM 

Please respond to

 kitfox-list(at)matronics.com     To

 kitfox-list(at)matronics.com   cc

    Subject

 Re: Re: 26 foot Clipped Wing Kitfox 

     

 

 

 

--> Kitfox-List message posted by: Lynn Matteson <lynnmatt(at)jps.net>

 

 Hey, we've missed you Luis....it's not like this all the time...why,  

 just last week we were all enjoying talking about tailwheels, or  

 maybe that was just me enjoying it, while some others suffered. : )

 

 If you're still tuned in, some of us are also "flying weekly" if not  

 daily. Why not tell us about some of your flying adventures...that  

 seems to be the hot topic.

 

 

 Lynn Matteson

 Kitfox IV Speedster, taildragger

 Jabiru 2200, #2062, 600.2 hrs

 Sensenich 62x46

 Electroair direct-fire ignition system

 New skis done and flying

 do not archive

 

 

 

 On Jan 22, 2009, at 8:56 PM, wingnut wrote:

 

 > --> Kitfox-List message posted by: "wingnut" <wingnut(at)spamarrest.com>

 >

 > Wow. Posts like this are the reason I stopped reading this forum. I  

 > poke in once in three months and I'm not disappointed. Glad to know  

 > I'm not missing much. Thanks!

 >

 >

 >> You are very wrong about that AKFlyer, the short wing Pipers have  

 >> a horrible reputation, and rightfully so. There is a really good  

 >> reason manufacturers of modern airplanes have not imitated these  

 >> short winged Pipers, and why the short winged pipers have not been  

 >> produced in many many years and have never been copied ( Unlike  

 >> the Piper Cub ). So despite your " Flawed Reasoning " and somewhat  

 >> appealing an nostalgic post relating to old pipers, what you say  

 >> is just bad information. I would hope most people here are smart  

 >> enough to realize bad information even when it is presented by  

 >> some slick, smoothing talking, snake oil salesman.

 >>

 >> Given aerodynamic information available these days, it is a really  

 >> bad idea to clip the wings that short. Just look at the wingspans  

 >> of most modern Light Sport Aircraft today, their wings have a  

 >> pretty high aspect ratio, there is a very good reason for that.

 >

 >

 > --------

 > Luis Rodriguez

 > Model IV 1200

 > Rotax 912UL

 > Flying Weekly

 > Laurens, SC (34A)

 >

 >

 >

 >

 > Read this topic online here:

 >

 > http://forums.matronics.com/viewtopic.php?p=226271#226271

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

larry huntley

Joined: 19 Jul 2008
Posts: 149

Posted: Thu Jan 22, 2009 7:02 pm Post subject: 26 foot Clipped Wing Kitfox

Mike,

  I need to know all I can learn about the short wing Piper's horrible 

reputation . I have about 3000 hrs in 5 different short wing Pipers. My wife 

and I have been in every state except Hawaii and most of Canada in the 27 

yrs we have been flying our Tripacer N8835D . I have a few hundred hrs in 

Vagabonds and probably 50 or so in a Pacer. Maybe I should be more careful. 

Do you think I am putting my wife and myself in danger? I had no idea. Thank 

you for the warning.            You may have saved Leonard's life also, 

Whew.

              Larry Huntley,Kitfox 4-1200, Soob, AMAX redrive 500+hrs



---

_________________
Larry Huntley,Dundee,NY
Kitfox 4-1200 N234EE
EA81,AMAX Redrive Warp 3 blade

av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Thu Jan 22, 2009 9:12 pm Post subject: Re: 26 foot Clipped Wing Kitfox

C'mon gang, let's keep this thread civil and productive.  And let's face it, until one of us actually tries a 26 ft wing mod, none of us really knows what the results will be.    



I don't want to create big debates about all this, so maybe if I can better explain my logic it will help everyone to better understand why I believe this will work as I think it will;



#1 - When Skystar clipped the standard Kitfox wing 3 ft to create the Speedster, they found they increased the stall speed only minimally, lost very little climb rate, but gained approximately 8-12 mph in speed.  That tells me that there is apparently still plenty of wing area for the weight of the airplane.  



#2 - If you do a wing loading calculation for a 650 lb model IV with the 26 ft wing vs a 825 lb Model 5-7 Kitfox with a full length wing, the wing loadings for both airplanes are virtually the same assuming the same cabin and fuel load (I used 300 lbs for the example below). 



Here's my math; 

Model IV w/26 ft wing (at) 950 lbs -:- 107 sq ft = 8.8 lbs sq ft

Model 7 w/32 ft wing (at) 1125 lbs -:- 131 sq ft = 8.6 lbs sq ft



So, a 26 ft M4 does in fact have a similar wing loading to a newer Kitfox with the longer, full span wing.  If the newer Fox had a Speedster 29' wing, it is likely to have worse overall performance than the 26' M4.



#3 - One of the most popular homebuilts ever created is the Van's RV series.  They are not only fast long distance cruisers, but also have relatively slow stall speeds and good short field capability considering their high top speed capability.  Statistically, an early RV-3 weighs 750 lbs empty, has a top speed of 207 mph, a climb rate of 2050 fpm, and a stall speed of 51 mph.  All that on a measly 19 ft wing with only 90 sq ft of area.  And if you look at any of the other RV series airplanes, you will see similar information.  The longest wing they use on any of their models is 28 ft, but ironically that model has a 30+ slower top speed, a climb rate that is 1/2 that of the shorter wing models,  and a stall speed that is only 3-5 mph slower than the short wings.  So much for thinking you can't have a short wing airplane perform well for a wide speed range.  The popularity of the RV series is testimony to that, as they are highly regarded for their excellent handling and outstanding performance.  



#4 - The crude "guess-timate" I came up with for performance is based primarily on information I took out of a book titled "Design for Flying", written by David Thurston, a Grumman aircraft designer that is best known for having designed the Lake Amphibian.  I own a Lake Amphibian in addition to my Kitfoxes, and after having put 900+ hours on it, I have a huge respect for Mr. Thurstons  design and engineering abilities (a Lake is a very complex, but efficient design).  So I am pretty confident my basic information and theory on this Kitfox wing modification is reasonably well founded.



Once again, I don't mean to cause any big heated debates over this idea.  I just thought it would be neat to get some input from the group before I start cutting spar tubes.



Paul



ps - Akflyer;  I'd love to see those pics of your friends flaperon extensions.  Oh yeah, I have some time in a 135 hp and a 150 hp Pacer.  In my opinion the short wing Pipers are highly misunderstood, and underappreciated airplanes.  I think anyone that flies one long enough to understand it will learn to love it.  Incidently, our Avid/Kitfox designer Dean Wilson told me the Piper Clipper is one of his most favorite airplanes.  He just finished restoring a custom one for himself.

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

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