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fuel cap faring

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kirkhull(at)kc.rr.com
Guest

Posted: Tue Mar 11, 2008 5:39 pm Post subject: fuel cap faring

When I was at osh last year I saw a # of kitfoxes with some faring behind

the fuel caps.  Does anybody know where to find these and how much they

cost?  If anybody has these installed was there any noticeable effects?

dcsfoto

Joined: 24 Aug 2006
Posts: 120

Posted: Tue Mar 11, 2008 6:34 pm Post subject: Re: fuel cap faring

got mine from Kitfox



David

patreilly43(at)hotmail.co
Guest

Posted: Tue Mar 11, 2008 6:52 pm Post subject: fuel cap faring

Murle Williams has the gas cap fairings (at) Williams Aviation. He's in AZ, but will ship anywhere.

  

 Pat Reilly

 Mod 3 Rebuild

 Rockford, IL



 	  Quote: 	
		   From: kirkhull(at)kc.rr.com

 To: kitfox-list(at)matronics.com

 Subject: fuel cap faring

 Date: Tue, 11 Mar 2008 19:37:20 -0600

 

 --> Kitfox-List message posted by: "kirk hull" <kirkhull(at)kc.rr.com>

 

 When I was at osh last year I saw a # of kitfoxes with some faring behind

 the fuel caps. Does anybody know where to find these and how much they

 cost? If anybody has these installed was there any noticeable effects?> 

 

 


	


  [quote][b]

Fox5flyer
Guest

Posted: Wed Mar 12, 2008 3:47 am Post subject: fuel cap faring

I made my own.  It was fairly simple.  Just used 3/4" blue foam carved to 

shape, sanded, covered with a thin layer of glass/epoxy, paint to match, 

then epoxied to the wing.   Photos attached.  Sorry about the photo quality. 

They were taken a long time ago when digital cams were infantile.

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"The aim of an argument or discussion should not be victory, but progress."

- Joseph Joubert



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n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Mar 12, 2008 6:38 am Post subject: Re: fuel cap faring

Ah, the gas cap fairings! 



The main thing is you need to install speed brakes, and a an F-4 Phantom

style drag chute for landings!



On my plane, I can switch between 6.00x6 tires, and 8.50x6 tires and barely

notice any speed change, so I'm a bit skeptical about the gas cap fairings.

My cruise speed with an IO-240B is about 120 at 2400 rpm's, and at full

power at 2800 I can hit 140 in level flight. This is pretty consistent for

me regardless of what tires I hang under it, or if I put my landing light

bar under the plane (three 6" dia. lights).



It obviously won't hurt to put them on, but I wouldn't expect to gain any

speed from it.



Regards,

Jeff.

patreilly43(at)hotmail.co
Guest

Posted: Wed Mar 12, 2008 7:09 am Post subject: fuel cap faring

Jeff, I can get the drag chute from JEGS or Summit. Where can I get those speed brakes? 

  

 Do not archieve

  

 Pat Reilly

 Mod 3 Rebuild

 Rockford, IL



 	  Quote: 	
		   Subject: Re: fuel cap faring

 From: n85ae(at)yahoo.com

 Date: Wed, 12 Mar 2008 07:38:04 -0700

 To: kitfox-list(at)matronics.com

 

 --> Kitfox-List message posted by: "n85ae" <n85ae(at)yahoo.com>

 

 Ah, the gas cap fairings! 

 

 The main thing is you need to install speed brakes, and a an F-4 Phantom

 style drag chute for landings!

 

 On my plane, I can switch between 6.00x6 tires, and 8.50x6 tires and barely

 notice any speed change, so I'm a bit skeptical about the gas cap fairings.

 My cruise speed with an IO-240B is about 120 at 2400 rpm's, and at full

 power at 2800 I can hit 140 in level flight. This is pretty consistent for

 me regardless of what tires I hang under it, or if I put my landing light

 bar under the plane (three 6" dia. lights).

 

 It obviously won't hurt to put them on, but I wouldn't expect to gain any

 speed from it.

 

 Regards,

 Jeff.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=169234#169234

 

 

 

 

 

 > 

 

 


	


  [quote][b]

Fox5flyer
Guest

Posted: Wed Mar 12, 2008 7:26 am Post subject: fuel cap faring

Ahhh, Jeff, my old draggy friend.  Skepticism is good.  Nothing wrong with 

that.  In the past you have made it well known how you feel about fairings, 

which is fine, but we all have our opinions here.  The vast majority of us 

don't have 125hp to play with.  Most have 100hp or less.  I'm a firm 

believer that every little bit counts when it comes to cleaning up the 

airplane.  It's probably not linear, but it all adds up, no matter how small 

each item is.  Some things are more effective than others, depending on what 

part of the airplane is causing the drag.

As for my reason for the fairings, it wasn't so much as to reduce drag, but 

to clean up the top surface of the wing.  A long time ago, one of our list 

members did a oil drop test to see how much the air was disturbed behind the 

gas caps.  Oil drop is where you take a thick oil and put a bunch of drops 

on top of the wing all around the spot you want to test.  Then you go fly 

and when you get on the ground, jump out and take a quick photo of what you 

see.  What he found was that immediately behind the gas cap the air was 

stalled and it widened out to a point about 18" at the trailing edge of the 

wing.  In my opinion, when you add both wings together, that was a pretty 

big chunk of lifting surface not providing any lift.  So, since it was a 

long winter, and nothing much else was going on, I decided to kill two birds 

with one fairing, well two.  Regarding the gas caps, most of the parasitic 

drag and loss of lift were resolved.  I can't quantify in numbers what it 

adds up to, but the weight was probably less than 2oz total and they sure 

don't hurt anything.  The benefits are increased speed with less throttle 

meaning better efficiency which translates to fuel saved.  Seems like a no 

brainer to me.

As for a drag chute, I can recall a couple landings when I wish I'd had one. 

Would have saved a go round.

Slick is good.  

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"The aim of an argument or discussion should not be victory, but progress."

- Joseph Joubert



---

avidfox

Joined: 03 Apr 2007
Posts: 87

Posted: Wed Mar 12, 2008 8:12 am Post subject: fuel cap faring

"How many people make themselves abstract to appear profound. The most useful part of abstract terms are the shadows they create to hide a vacuum. "

   

 Joseph Joubert......also.

 

 

  [quote][b]

n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Mar 12, 2008 8:41 am Post subject: Re: fuel cap faring

Hey Deke -



You are correct, that every little bit helps. Also it is a hobby, so nothing 

wrong with it in the least. 



My points more come from - That in he world of basic aerodynamics, 

regardless of what you do, the basic design itself IS the REAL issue. No

matter how much you tweak a Kitfox, you will only ever make minor 

improvements.



I think some times from the list, you get the impression that people 

think they will get a 40 mph gain from all these enhancements. You 

simply can't. 



The higher horsepower IO-240B really brings this to light. I have a good

bit of power however it becomes clear when I fly that the drag is very

much increasing exponentially and it hits a wall at about 120-140 mph

where you either need another 200 or so horsepower, or some pretty

significant drag reductions to go faster. 



When I say significant, I mean like an entirely different wing and 

fuselage. 



Anyway, that's the only real point.



Regards,

Jeff



P.S. I really posted it to - antagonize Deke. But that's another story ...

n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Mar 12, 2008 8:47 am Post subject: Re: fuel cap faring

You might try http://www.jamestowndistributors.com



Look under "anchors"



Regards,

Jeff



[quote="patreilly43(at)hotmail.co"]Jeff, I can get the drag chute from JEGS or Summit. Where can I get those speed brakes? 

  

 Do not archieve

  

 Pat Reilly

 Mod 3 Rebuild

 Rockford, IL



 	  Quote: 	
		   Subject: Re: fuel cap faring

 From: n85ae(at)yahoo.com

 Date: Wed, 12 Mar 2008 07:38:04 -0700

 To: kitfox-list(at)matronics.com

 

 --> Kitfox-List message posted by: "n85ae" <n85ae>

 

 Ah, the gas cap fairings! 

 

 The main thing is you need to install speed brakes, and a an F-4 Phantom

 style drag chute for landings!

 

 On my plane, I can switch between 6.00x6 tires, and 8.50x6 tires and barely

 notice any speed change, so I'm a bit skeptical about the gas cap fairings.

 My cruise speed with an IO-240B is about 120 at 2400 rpm's, and at full

 power at 2800 I can hit 140 in level flight. This is pretty consistent for

 me regardless of what tires I hang under it, or if I put my landing light

 bar under the plane (three 6" dia. lights).

 

 It obviously won't hurt to put them on, but I wouldn't expect to gain any

 speed from it.

 

 Regards,

 Jeff.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=169234#169234

 

 

 

 

 

 > 

 

 



	


   	  Quote: 	
		  [b]

propellerdesign(at)tele2.
Guest

Posted: Wed Mar 12, 2008 10:08 am Post subject: fuel cap faring

Kitfoxers!



Even small improvement help to gain speed, or reduce fuel burn, but it all 

is relative, just as intelligence is.



small wheels and wheelpants might make 2-3 miles on a kitfox, 10-15 miles on 

a KR-2.



I ones read about a EUROPA that had perfect made fillets between wing and 

fuselage, when sealing the fillets to fuselage with tape it was going 10 

knots faster, like flying with parking brake set! This one hade a constant 

speed prop!

With a fixed pitch prop, and cruising at a curtain RPM you will not notice 

much improvement until you calculate your fuel consumption. at WOT you will 

see increase in RPM and speed.



going from 65 hp and say 102 MPH to a 125 hp will gain 24% more speed in 

theory, = 127 MPH



In practice - maybe - maybe not, the whole concept is often designed for a 

predetermined speed range, wing area, airfoil and incidence is chosen for 

this speed, flying with tail scraping the sky and propeller pointing towards 

the earth isn't optimal. a different airfoil, smaller wing, higher weight or 

little of all three will make a difference.

Weight cost speed too.



With today's fuel price aerodynamic improvement isn't all wrong, it isn't 

1-2 dollar a gallon any more. but as the blond girl said: "I just buy gas 

for one hundred anyway" blinked here eye and drove away!



It is easy to add drag to a airplane but difficult to reduce it!



Jan

---

Fox5flyer
Guest

Posted: Wed Mar 12, 2008 10:33 am Post subject: fuel cap faring

Jeff, the perennial smartass, but thanks for adding some humor to this list. 



Deke

do not archive



 	  Quote: 	
		  

 You might try http://www.jamestowndistributors.com



 Look under "anchors"



 Regards,

 Jeff

Fox5flyer
Guest

Posted: Wed Mar 12, 2008 10:40 am Post subject: fuel cap faring

Jeff, you are absolutely correct in that the Kitfox is only capable of so 

much cleanup.  I can't argue that.  If you want lift, you gotta compromise 

with drag, so it's a draggy airplane, but not as bad as many others out 

there and there is room to get some more knots out of it without derogating 

the mission.  When it comes to buying gas, I'm a real cheapskate and if I 

can get a few more miles per gallon without adding much weight, that's what 

I'll do.  Like you said, it's a hobby, a quest, a mission, or perhaps even 

an obsession.

Antagonized in Mikado, MI

Sunny, warming up and spring is springing

Whaoo!

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 355+ TT

"The aim of an argument or discussion should not be victory, but progress."

- Joseph Joubert



 	  Quote: 	
		  

 Hey Deke -



 You are correct, that every little bit helps. Also it is a hobby, so 

 nothing

 wrong with it in the least.



 My points more come from - That in he world of basic aerodynamics,

 regardless of what you do, the basic design itself IS the REAL issue. No

 matter how much you tweak a Kitfox, you will only ever make minor

 improvements.



 I think some times from the list, you get the impression that people

 think they will get a 40 mph gain from all these enhancements. You

 simply can't.



 The higher horsepower IO-240B really brings this to light. I have a good

 bit of power however it becomes clear when I fly that the drag is very

 much increasing exponentially and it hits a wall at about 120-140 mph

 where you either need another 200 or so horsepower, or some pretty

 significant drag reductions to go faster.



 When I say significant, I mean like an entirely different wing and

 fuselage.



 Anyway, that's the only real point.



 Regards,

 Jeff



 P.S. I really posted it to - antagonize Deke. But that's another story ... 

 





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=169283#169283

n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Mar 12, 2008 10:55 am Post subject: Re: fuel cap faring

Ah, when it comes to buying gas, my wife is a real cheapskate. When

I built mine I was single, and working as a consultant ($$$) and trying 

to figure out how to put a 5000 hp Allison T-56 Turboprop on it.



Now that I'm married, I'm looking at solar power ...



Jeff



 	  Quote: 	
		  When it comes to buying gas, I'm a real cheapskate

patreilly43(at)hotmail.co
Guest

Posted: Wed Mar 12, 2008 12:00 pm Post subject: fuel cap faring

Deke, I see your gas cap fairings have a piece in front as well as behind the cap. I think the ones you buy have only a piece behind the cap. Being an old canoe builder I know that the increased lineal length to part and return the air is more efficient. Was there any "testing" done in your design or was it an eyeballed design?

  

 Pat Reilly

 Mod 3 Rebuild

 Rockford, IL



[quote] From: fox5flyer(at)idealwifi.net

 To: kitfox-list(at)matronics.com

 Subject: fuel cap faring

 Date: Wed, 12 Mar 2008 11:21:36 -0400

 

 --> Kitfox-List message posted by: "fox5flyer" <fox5flyer(at)idealwifi.net>

 

 Ahhh, Jeff, my old draggy friend. Skepticism is good. Nothing wrong with 

 that. In the past you have made it well known how you feel about fairings, 

 which is fine, but we all have our opinions here. The vast majority of us 

 don't have 125hp to play with. Most have 100hp or less. I'm a firm 

 believer that every little bit counts when it comes to cleaning up the 

 airplane. It's probably not linear, but it all adds up, no matter how small 

 each item is. Some things are more effective than others, depending on what 

 part of the airplane is causing the drag.

 As for my reason for the fairings, it wasn't so much as to reduce drag, but 

 to clean up the top surface of the wing. A long time ago, one of our list 

 members did a oil drop test to see how much the air was disturbed behind the 

 gas caps. Oil drop is where you take a thick oil and put a bunch of drops 

 on top of the wing all around the spot you want to test. Then you go fly 

 and when you get on the ground, jump out and take a quick photo of what you 

 see. What he found was that immediately behind the gas cap the air was 

 stalled and it widened out to a point about 18" at the trailing edge of the 

 wing. In my opinion, when you add both wings together, that was a pretty 

 big chunk of lifting surface not providing any lift. So, since it was a 

 long winter, and nothing much else was going on, I decided to kill two birds 

 with one fairing, well two. Regarding the gas caps, most of the parasitic 

 drag and loss of lift were resolved. I can't quantify in numbers what it 

 adds up to, but the weight was probably less than 2oz total and they sure 

 don't hurt anything. The benefits are increased speed with less throttle 

 meaning better efficiency which translates to fuel saved. Seems like a no 

 brainer to me.

 As for a drag chute, I can recall a couple landings when I wish I'd had one. 

 Would have saved a go round.

 Slick is good. 

 Deke Morisse

 Mikado Michigan

 S5/Subaru/CAP 355+ TT

 "The aim of an argument or discussion should not be victory, but progress."

 - Joseph Joubert

 

 ---

Fox5flyer
Guest

Posted: Wed Mar 12, 2008 1:43 pm Post subject: fuel cap faring

Nah,  it was eyeballed.  I was just bored and  decided I liked the look of putting the piece in front to make it look more  aerodynamic.  Probably no measurable difference at my speeds.

 Deke

  

 [quote]   ---

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