---------------------------------------------------------- Kitfox-List Digest Archive --- Total Messages Posted Thu 06/14/07: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:49 AM - Re: Unequal fuel flow (n85ae) 2. 06:59 AM - Re: engine out logic ?? (n85ae) 3. 07:11 AM - Re: Re: Unequal fuel flow (Rick) 4. 07:59 AM - Unequal fuel flow (mikeperkins) 5. 10:04 AM - Tab on Rudder (Mike Chaney) 6. 10:44 AM - Re: Tab on Rudder (kerrjohna@comcast.net) 7. 12:03 PM - Re: Unequal fuel flow (Guy Buchanan) 8. 12:10 PM - Re: Tab on Rudder (Guy Buchanan) 9. 01:09 PM - Re: Tab on Rudder (A Smith) 10. 01:28 PM - Re: Tab on Rudder (kurt schrader) 11. 03:41 PM - Landing light lense??? (George Michaels) 12. 04:09 PM - Re: Unequal fuel flow (john oakley) 13. 04:56 PM - Re: Tab on Rudder (Marco Menezes) 14. 07:07 PM - Re: Unequal fuel flow (Guy Buchanan) 15. 09:57 PM - What is the main spar material 6061T6 ? (Marwynne Kuhn) ________________________________ Message 1 _____________________________________ Time: 06:49:38 AM PST US Subject: Kitfox-List: Re: Unequal fuel flow From: "n85ae" This is absolutely simple, it is a very common problem, and it is caused by the use of a single header vent line. If the Kitfox design had vents to both tanks the problem wouldn't be there. It is common to many other high wing designs with similar fuel systems. The best thing to do, is simply fly the plane and ignore it. You will still feed all the fuel from both tanks (less unusable) to the header before you fall out of the sky. Jeff Hays Series 5, IO240B Read this topic online here: http://forums.matronics.com/viewtopic.php?p=118397#118397 ________________________________ Message 2 _____________________________________ Time: 06:59:18 AM PST US Subject: Kitfox-List: Re: engine out logic ?? From: "n85ae" I fly every minute I'm flying with the assumption that the engines going to quit. I started flying in Colorado, and I now fly around Chicago. Both mountainous terrain, and suburbia have equal appeal to me for landing. So I always deviate within reach of fields, etc. Having had an engine failure, is a religious experience. At first you don't believe it quit, then you're next thought is "Oh %^$%!". That and groundlooping my plane were the two most significant things that I think made me a smarter/safer pilot. Having my vaccum pump make loud shrieking noises during a night flight made me rethink the wisdom of flying single engine at night over the suburbs as well. Jeff Hays Series 5, IO-240B Read this topic online here: http://forums.matronics.com/viewtopic.php?p=118399#118399 ________________________________ Message 3 _____________________________________ Time: 07:11:04 AM PST US From: "Rick" Subject: RE: Kitfox-List: Re: Unequal fuel flow Jeff you are right. Of more concern should be steep decent with less than 6 or 7 gals fuel onboard. Provided you have dual tanks. There are post on this issue though. Rick -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of n85ae Sent: Thursday, June 14, 2007 6:49 AM Subject: Kitfox-List: Re: Unequal fuel flow This is absolutely simple, it is a very common problem, and it is caused by the use of a single header vent line. If the Kitfox design had vents to both tanks the problem wouldn't be there. It is common to many other high wing designs with similar fuel systems. The best thing to do, is simply fly the plane and ignore it. You will still feed all the fuel from both tanks (less unusable) to the header before you fall out of the sky. Jeff Hays Series 5, IO240B Read this topic online here: http://forums.matronics.com/viewtopic.php?p=118397#118397 6/13/2007 12:50 PM 6/13/2007 12:50 PM ________________________________ Message 4 _____________________________________ Time: 07:59:07 AM PST US Subject: Kitfox-List: Unequal fuel flow From: "mikeperkins" Conducting a fuel-flow test on the ground is always a good idea. The fuel rate should be measured by removing the fuel hose from the carb.....anywhere else and the head pressure is going to be different and therefore yield incorrect results. Also, fuel flow should be measured on the ground with the airplane set in three different attitudes: the cruise-flight attitude, approach attitude, and max climb. The FAA wants about 1.5 times your max fuel usage in any attitude. Feeding from each tank separately and all combinations thereof, including all tanks, is also necessary. This will reveal obstructions or problems with fuel line routing. When it comes to uneven fuel flow between the tanks, the tank pressures can vary. Many Kitfoxes have ram-pressure caps (with the bent-forward vent pipes). but whether an airplane has ram caps or not, the fuel flow difference mostly reflects the difference in tank pressures and fuel-flow turbulence. A sharp 90-degree bend, for example, will create a lot of turbulence, even at low flow-rates. Essentially, the turbulence creates a pressure drop. Each pressure drop subtracts from the tank pressure. Obviously, this kind of testing can only be done in flight or with very sophisticated ground equipmment. Therefore, fuel flow is related to pressures and pressure drops - in other words, the sums and differences of all pressures. For whatever reason, my Kitfox has about a 30% difference between flow when tanks are near full, but as the tanks empty towards 1/4 full, the tank quanitiy seems to even out. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=118414#118414 ________________________________ Message 5 _____________________________________ Time: 10:04:28 AM PST US From: Mike Chaney Subject: Kitfox-List: Tab on Rudder I have to use alot of right rudder on my model IV. This became an issue after I installed the Jabiru 2200. This isn't a big problem but I would like to fix it. If I want to place a tab on my rudder which side should it go on? Could I use a small piece of bent lexan for the tab? I think I know the answer but sometimes things are counterintuitive. Mike Chaney 1996 Kitfox Model IV Jabiru 2200 ________________________________ Message 6 _____________________________________ Time: 10:44:37 AM PST US From: kerrjohna@comcast.net Subject: Re: Kitfox-List: Tab on Rudder I placed mine on the left side of the rudder so that it would push rather than pull the rudder to the right. I would suggest you consider using aluminum so that you can tweek it to have the ball centered at your normal cruise speed, in the case of N195KF it is bent for equilibrium at 92 kts. It is located at the bottom curve of the trailing edge so that advantage can be taken of the leverage provided in riviting to the bottom portion of the tubing. (Not three rivits in a straight line). You could similarly mount it at the top curve thereby avoiding any wind shadow created by the fuselage. I have also seen a stronger spring/shorter connection used on the right rudder pedal to address the issue. The tab is more effective I believe at varying speeds and easier to tweek in order to get it right. John Kerr N195KF Classic IV,912UL -------------- Original message -------------- From: Mike Chaney I have to use alot of right rudder on my model IV. This became an issue after I installed the Jabiru 2200. This isn't a big problem but I would like to fix it. If I want to place a tab on my rudder which side should it go on? Could I use a small piece of bent lexan for the tab? I think I know the answer but sometimes things are counterintuitive. Mike Chaney 1996 Kitfox Model IV Jabiru 2200
I placed mine on the left side of the rudder so that it would push rather than pull the rudder to the right.  I would suggest you consider using aluminum so that you can tweek it to have the ball centered at your normal cruise speed, in the case of N195KF it is bent for equilibrium at 92 kts.  It is located at the bottom  curve of the trailing edge so that advantage can be taken of the leverage provided in riviting to the bottom portion of the tubing. (Not three rivits in a straight line).  You could similarly mount it at the top curve thereby avoiding any wind shadow created by the fuselage. I have also seen a stronger spring/shorter connection used on the right rudder pedal to address the issue.  The tab is more effective I believe at varying speeds and easier to tweek in order to get it right.
 
John Kerr
N195KF
Classic IV,912UL
 
-------------- Original message --------------
From: Mike Chaney <mdps_mc@swoca.net>
I have to use alot of right rudder on my model IV.  This became an issue after I installed the Jabiru 2200.   This isn't a big problem but I would like to fix it.  If I want to place a tab on my rudder which side should it go on?  Could I use a small piece of bent lexan for the tab?  I think I know the answer but sometimes things are counterintuitive.
 
Mike Chaney
1996 Kitfox
Model IV
Jabiru 2200
________________________________ Message 7 _____________________________________ Time: 12:03:49 PM PST US From: Guy Buchanan Subject: RE: Kitfox-List: Unequal fuel flow At 10:01 PM 6/13/2007, you wrote: >I will try not to confuse, there is two problems, one the vent line >and two the tanks draining differently. John, I've been trying to figure this out, since it has come up before. >The vent line is only to get the gas (air) out of the header tank. >If the vent is left open, there is a possibility that the header >tanks could empty and the engine will suck air through the vent line. This presumes BOTH tank fuel lines are blocked, right? If either fuel line is flowing, there is no way to pull vapor through the vent line as the level in the vent line is the same as the level in the flowing tank. (Fluid seeks it's own level.) >Now, let me explain that, each of the fuel tanks has a line that has >a loose 90 degree turn to get to the tank (just behind your head), >this turn is usually left fairly loose or large so the wing can fold >with out tearing the line out. This half loop can if left too loose, >can get a bubble in it during a turn. This bubble can cause a "vapor >lock" and the tank will stop feeding. If it stops feeding the header >tank empties and sucks air from the vent line. There is no vapor lock, the high hose simply acts as a dam over which fuel cannot flow. The tank will gravity feed, however, down to the level of the highest point of the hose. (If the loop rises above the tank then you can't gravity feed. You must siphon.) Then if there's suction you can siphon the fluid over the dam, even with an air bubble. The only time the siphon will fail is if it pulls air instead of fluid. If the flow is very slow the bubble will reside in the top of the loop and fuel will flow past it. If the flow is fast it may pull the bubble along with it. If your pump isn't self priming this bubble can cause it to stop pulling. (As in a 582 oil pump.) I tried all of these scenarios with water and clear hose and couldn't generate your "vapor lock" no matter what I did. The fluid in my "tank" always drained down to the level of the top of the hose. Then if I used suction, (via siphon or mechanically,) I could continue to drain the "tank" until I sucked air. Guy Buchanan San Diego, CA K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar. ________________________________ Message 8 _____________________________________ Time: 12:10:01 PM PST US From: Guy Buchanan Subject: Re: Kitfox-List: Tab on Rudder At 10:04 AM 6/14/2007, you wrote: >If I want to place a tab on my rudder which side should it go >on? Could I use a small piece of bent lexan for the tab? I think I >know the answer but sometimes things are counterintuitive. To get right rudder use left tab. A harder question is how much. You could use Lexan, but the reason most use aluminum is that it's easy to bend to get the right amount of trim. You could first do the aluminum tab, get the size and angle right, then make one out of Lexan. Guy Buchanan San Diego, CA K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar. ________________________________ Message 9 _____________________________________ Time: 01:09:55 PM PST US From: "A Smith" Subject: Re: Kitfox-List: Tab on Rudder I did about the same thing as John Kerr. I used a fairly long piece 6" long and 3" from the trailing edge. The front of it extends out over the lower horizontal tube a couple of inches. This takes out the twisting on the rear vertical tube. I then glued and rivited it in place. It will fly feet off at a fairly broad speed range. Albert Smith 5TD, NSI turbo and Cap 3 blade ________________________________ Message 10 ____________________________________ Time: 01:28:08 PM PST US From: kurt schrader Subject: Re: Kitfox-List: Tab on Rudder Hi Mike, It is possible that your new engine is mounted to pull just a bit left. It doesn't take much to make it pull a lot. You might consider shimming it at the mounts to have it pull more right. This means that your cowling might not line up as exact though. Not a big deal with the round cowl, but the other one will show the change. I adjusted mine by about 3/16th inch and it made a big difference. Kurt S. S-5?NSI turbo Florida and Panama --- Mike Chaney wrote: > I have to use alot of right rudder on my model IV. > This became an issue after I installed the Jabiru > 2200....... > > Mike Chaney > 1996 Kitfox > Model IV > Jabiru 2200 Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more. http://mobile.yahoo.com/go?refer=1GNXIC ________________________________ Message 11 ____________________________________ Time: 03:41:22 PM PST US From: George Michaels Subject: Kitfox-List: Landing light lense??? Someone have know where to get a set of landing light lenses. ________________________________ Message 12 ____________________________________ Time: 04:09:16 PM PST US From: "john oakley" Subject: RE: Kitfox-List: Unequal fuel flow Good grief Guy, :-) Ok, it is not a vapor lock; I was trying to get the point across. The fact remains that; we can loose an aircraft due to this problem. In addition, if the vent line is open you will suck air instead of fuel when the level of fuel equals the top of the hose. John Oakley _____ From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Guy Buchanan Sent: Thursday, June 14, 2007 1:02 PM Subject: RE: Kitfox-List: Unequal fuel flow At 10:01 PM 6/13/2007, you wrote: I will try not to confuse, there is two problems, one the vent line and two the tanks draining differently. John, I've been trying to figure this out, since it has come up before. The vent line is only to get the gas (air) out of the header tank. If the vent is left open, there is a possibility that the header tanks could empty and the engine will suck air through the vent line. This presumes BOTH tank fuel lines are blocked, right? If either fuel line is flowing, there is no way to pull vapor through the vent line as the level in the vent line is the same as the level in the flowing tank. (Fluid seeks it's own level.) Now, let me explain that, each of the fuel tanks has a line that has a loose 90 degree turn to get to the tank (just behind your head), this turn is usually left fairly loose or large so the wing can fold with out tearing the line out. This half loop can if left too loose, can get a bubble in it during a turn. This bubble can cause a =13vapor lock=14 and the tank will stop feeding. If it stops feeding the header tank empties and sucks air from the vent line. There is no vapor lock, the high hose simply acts as a dam over which fuel cannot flow. The tank will gravity feed, however, down to the level of the highest point of the hose. (If the loop rises above the tank then you can't gravity feed. You must siphon.) Then if there's suction you can siphon the fluid over the dam, even with an air bubble. The only time the siphon will fail is if it pulls air instead of fluid. If the flow is very slow the bubble will reside in the top of the loop and fuel will flow past it. If the flow is fast it may pull the bubble along with it. If your pump isn't self priming this bubble can cause it to stop pulling. (As in a 582 oil pump.) I tried all of these scenarios with water and clear hose and couldn't generate your "vapor lock" no matter what I did. The fluid in my "tank" always drained down to the level of the top of the hose. Then if I used suction, (via siphon or mechanically,) I could continue to drain the "tank" until I sucked air. Guy Buchanan San Diego, CA K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar. ________________________________ Message 13 ____________________________________ Time: 04:56:25 PM PST US From: Marco Menezes Subject: Re: Kitfox-List: Tab on Rudder How about a photo John? My model 2 yaws right at cruise (70 mph). Left foot gets tired. Otherwise, she flies hands-off. kerrjohna@comcast.net wrote: I placed mine on the left side of the rudder so that it would push rather than pull the rudder to the right. I would suggest you consider using aluminum so that you can tweek it to have the ball centered at your normal cruise speed, in the case of N195KF it is bent for equilibrium at 92 kts. It is located at the bottom curve of the trailing edge so that advantage can be taken of the leverage provided in riviting to the bottom portion of the tubing. (Not three rivits in a straight line). You could similarly mount it at the top curve thereby avoiding any wind shadow created by the fuselage. I have also seen a stronger spring/shorter connection used on the right rudder pedal to address the issue. The tab is more effective I believe at varying speeds and easier to tweek in order to get it right. John Kerr N195KF Classic IV,912UL -------------- Original message -------------- From: Mike Chaney I have to use alot of right rudder on my model IV. This became an issue after I installed the Jabiru 2200. This isn't a big problem but I would like to fix it. If I want to place a tab on my rudder which side should it go on? Could I use a small piece of bent lexan for the tab? I think I know the answer but sometimes things are counterintuitive. Mike Chaney 1996 Kitfox Model IV Jabiru 2200 Marco Menezes Model 2 582 N99KX --------------------------------- Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us. ________________________________ Message 14 ____________________________________ Time: 07:07:41 PM PST US From: Guy Buchanan Subject: RE: Kitfox-List: Unequal fuel flow At 04:07 PM 6/14/2007, you wrote: >Good grief Guy, J > >Ok, it is not a vapor lock; I was trying to get the point across. I though so, but wanted to make sure. The fuel injected spam cans I fly get vapor lock on a hot start so I get confused. I just wanted to clarify what you were seeing. I guess I should have just asked, eh? :-[ Guy Buchanan San Diego, CA K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar. ________________________________ Message 15 ____________________________________ Time: 09:57:18 PM PST US From: "Marwynne Kuhn" Subject: Kitfox-List: What is the main spar material 6061T6 ? What are the spars of a Kitfox 6061T6 ? My measurements were for 2 1/2 inch .065 thickness ! I looked in the book and they didn't give the metal. Anyone know ? 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