---------------------------------------------------------- Kitfox-List Digest Archive --- Total Messages Posted Thu 03/02/06: 34 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:05 AM - SV: Orange peeling (Michel Verheughe) 2. 03:58 AM - Wheel Pants (Jimmie Blackwell) 3. 08:23 AM - Re: calculating Va (kurt schrader) 4. 08:57 AM - Re: calculating Va (Bradley M Webb) 5. 09:11 AM - calculating & subjective Va (alnanarthur) 6. 09:16 AM - Brakes and Rudder Pedals (Larry Martin) 7. 09:18 AM - Re: calculating Va (Andrew Matthaey) 8. 09:42 AM - Re: calculating & subjective Va (jdmcbean) 9. 10:01 AM - Re: calculating Va (jdmcbean) 10. 10:35 AM - Re: calculating Va (Fox5flyer) 11. 10:51 AM - Re: calculating & subjective Va (alnanarthur) 12. 12:28 PM - Re: calculating Va (Michel Verheughe) 13. 01:39 PM - Landing gear (Les James) 14. 01:59 PM - Re: calculating Va (Andrew Matthaey) 15. 02:13 PM - Re: calculating Va (Bradley M Webb) 16. 02:26 PM - Re: calculating Va (AMuller589@aol.com) 17. 03:05 PM - Va and rudder (Alan & Linda Daniels) 18. 03:41 PM - Re: calculating Va (What me worry?) (Lowell Fitt) 19. 04:35 PM - Re: calculating Va (alnanarthur) 20. 05:01 PM - Re: calculating Va (AMuller589@aol.com) 21. 06:09 PM - Re roiugh running (Rex Shaw) 22. 06:09 PM - Poly-Fiber stuff (Eric) 23. 06:09 PM - calculating Va (Clem Nichols) 24. 06:14 PM - Re: calculating & subjective Va (jdmcbean) 25. 06:17 PM - Re: calculating Va (wingsdown) 26. 07:02 PM - Re: calculating Va (jdmcbean) 27. 07:09 PM - Re: calculating Va (alnanarthur) 28. 07:40 PM - Re: calculating Va (Clem Nichols) 29. 07:44 PM - Gone West (Jay Carter) 30. 07:48 PM - Re: calculating Va (Bradley M Webb) 31. 08:02 PM - Re: calculating Va (jdmcbean) 32. 10:46 PM - Re: Re roiugh running (Lowell Fitt) 33. 11:12 PM - Re: Baggage compartment (kurt schrader) 34. 11:50 PM - Re: calculating Va (kurt schrader) ________________________________ Message 1 _____________________________________ Time: 12:05:42 AM PST US From: Michel Verheughe Subject: SV: Kitfox-List: Orange peeling --> Kitfox-List message posted by: Michel Verheughe > From: Glenn Horne [glennflys@verizon.net] > It is not for a fabric aircraft. Do not use it. Of course, Glenn, it's a yachtsman's product. But I thought Marco wanted to paint his cargo pod, not the fabric. ... maybe I misunderstood, in which case I apologize. Cheers, Michel do not archive ________________________________ Message 2 _____________________________________ Time: 03:58:55 AM PST US From: Jimmie Blackwell Subject: Kitfox-List: Wheel Pants --> Kitfox-List message posted by: Jimmie Blackwell I am looking for the hardware to install wheel pants, (I have wheel pants), on my Model IV with Grove gear. Would be happy to buy this hardware if anyone has it and willing to part with it. Jimmie ________________________________ Message 3 _____________________________________ Time: 08:23:42 AM PST US From: kurt schrader Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: kurt schrader Hi Bradley, You missed the point Michel brought up. It is not VA, but gauging turbulence without a G meter that makes the degree of turbulence subjective. VA is of course well defined. He just wanted to know when to apply it. :-) Kurt S. --- Bradley M Webb wrote: > Va, aka maneuvering speed, is not really subjective > at all............... ________________________________ Message 4 _____________________________________ Time: 08:57:38 AM PST US From: "Bradley M Webb" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Bradley M Webb" My understanding is that smooth is smooth, no bumps at all. Any bump (thermals, mountain wave, clear-air turbulence) requires a reduction to Va. I guess that is subjective, in that minor bumps can probably be ignored, but if there's a big one lurking up there... I do the same that most others do, I guess. I fly with my hand on the throttle to keep the airspeed manageable. I'm usually not in a big hurry, anyway. So reducing to 70mph is no big deal. An in-flight break-up is second only to mid-airs on my list of worst ways to die. By the time a G-meter tells you the info you're looking for, the wings will be gone. Again, IF you've exceeded the ultimate load factor (failure). I think that the reduction to Va is pre-emptive, to prevent the break-up before it happens. It's all about mitigating the risk. Bradley -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of kurt schrader Sent: Thursday, March 02, 2006 11:19 AM Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: kurt schrader Hi Bradley, You missed the point Michel brought up. It is not VA, but gauging turbulence without a G meter that makes the degree of turbulence subjective. VA is of course well defined. He just wanted to know when to apply it. :-) Kurt S. --- Bradley M Webb wrote: > Va, aka maneuvering speed, is not really subjective > at all............... ________________________________ Message 5 _____________________________________ Time: 09:11:24 AM PST US From: alnanarthur Subject: Kitfox-List: calculating & subjective Va --> Kitfox-List message posted by: alnanarthur Bradley, Kurt, Michel and all, When I bought my Kitfox Series 5, Skystar was in it's hayday. They had a bright aeronautical engineer employed at that time. In their lab, I saw an inverted wing set up loaded with sandbags. They said that they had tested the wing to an equivalent load factor of greater than 6 g ultimate. In my Series 5 Operating Handbook on page 2-4 it says: Flight Load Factors (flaps up) --------- +3.8, -1.52 Now if we trust Skystar's design numbers and if we assume that we have not degraded them during the building process then we can calculate Va. The load factor = (V/Vs)squared Therefore Va = squareroot (3.8 ( Vs squared)) For Vs = 45 , Va = 87.7 We, as builders, we can add a subjective factor. Say we want to limit the stress to 2 g. Then again for Vs = 45 and Load factor = 2, Va = 63.6 That is just about Vx for Series 5. To feel what 2g is like do a constant altitude turn at a 60 degree bank, but keep the airspeed above 63.6. The way Va saves the structure is that the wings stall before reaching the limiting load factor. Allan Arthur Kitfox 5, N40AA Rotax 912s, Warpdrive 3 blade Byron Airport (C83) Hanger C8 ________________________________ Message 6 _____________________________________ Time: 09:16:47 AM PST US From: "Larry Martin" Subject: Kitfox-List: Brakes and Rudder Pedals --> Kitfox-List message posted by: "Larry Martin" Rex, "..... I think I need to also shorten the brake cylinder rod ends. " If you do that, will you be increasing the amount of force that your foot would have to apply to the pedal to effect the same amount of psi at the brake? I had thought that Cylinder rod height, brake pedal height, all factors into the psi into the brake which results in psi to stop. (or something like that) Thanks for the posts about the water pressure gauge. Larry Subject: Brake and Rudder Pedals From: Rex Shaw (rexjan@bigpond.com) Date: Wed Mar 01 - 3:24 PM --> Kitfox-List message posted by: "Rex Shaw" I am curious to know whether anyone else finds the rudder pedals on the type V problematic in so far as being able to use the rudder function without inadvertently using brake. I find that it is very difficult to do so. Mine are adjusted to tilt top back as far as they can, but this still leaves them such that the foot wants to contact the top and apply brake even when this is not desired. Only by concentrating to place my foot on the very bottom part of the pedal, can brake be avoided. I am considering adding a step to the bottom of the pedal so the foot can 'find' the rudder only function more easily. Or is there a different pedal that someone has made to solve this problem? Or can the pedal be removed and modified to solve this? Duane Rueb Hi ! Duane, Yes I get the problem in my MKIV. I am over 6 ft tall with long size 10 feet. What I did is get 5/8" heater hose and slit it open down one side. You then need to cut out little notches where tubing leaves the horizontal rudder pedal. This moves your foot a little further away from the brakes. I used cable ties pulled real tight to hold the rubber in place however they did tend to move so I finished up using a bit of tie wire at the back of the pedal to hold the cable ties so they can't move out and off the end. I am thinking though that contact cement might be worthwhile. This certainly feels better and does help but is not a complete answer in all honesty. I think I need to also shorten the brake cylinder rod ends. Rather than mess with the existing ones. I think I will make new ones slightly shorter so the brake pedal leans a little forward. By making new ones I can the revert to the originals if required for any reason at any time. The rubber will stay though as I like it much better and it stops wearing the powder coating off. Rex. ________________________________ Message 7 _____________________________________ Time: 09:18:21 AM PST US From: "Andrew Matthaey" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Andrew Matthaey" The possibility of exceeding the design limitations of the Kitfox airframe are very rare...You can be completely comfortable bombing through a bit of turbulence here and there at your normal cruise speed. A speed reduction to Va is completely unnecessary. When was the last time turbulence had you pulling well over 2G's? Besides, Va is really only for haevy-pulling, maneuvering flight. If you are worried about stressing the airframe in turbulence, the speed you are interested in is Vno, or normal cruise speed. This is the speed at which, on GA aircraft, the ASI dial gets shaded yellow. It is also known as "turbulent air penetration speed." Just fly below Vno when in turbulence. No need to slow all the way down to Va! Andrew KF3 582 >From: "Bradley M Webb" >To: >Subject: RE: Kitfox-List: calculating Va >Date: Thu, 2 Mar 2006 11:56:32 -0500 > >--> Kitfox-List message posted by: "Bradley M Webb" > >My understanding is that smooth is smooth, no bumps at all. Any bump >(thermals, mountain wave, clear-air turbulence) requires a reduction to Va. >I guess that is subjective, in that minor bumps can probably be ignored, >but >if there's a big one lurking up there... > >I do the same that most others do, I guess. I fly with my hand on the >throttle to keep the airspeed manageable. I'm usually not in a big hurry, >anyway. So reducing to 70mph is no big deal. An in-flight break-up is >second >only to mid-airs on my list of worst ways to die. > >By the time a G-meter tells you the info you're looking for, the wings will >be gone. Again, IF you've exceeded the ultimate load factor (failure). I >think that the reduction to Va is pre-emptive, to prevent the break-up >before it happens. > >It's all about mitigating the risk. >Bradley > >-----Original Message----- >From: owner-kitfox-list-server@matronics.com >[mailto:owner-kitfox-list-server@matronics.com] On Behalf Of kurt schrader >Sent: Thursday, March 02, 2006 11:19 AM >To: kitfox-list@matronics.com >Subject: RE: Kitfox-List: calculating Va > >--> Kitfox-List message posted by: kurt schrader > > >Hi Bradley, > >You missed the point Michel brought up. It is not VA, >but gauging turbulence without a G meter that makes >the degree of turbulence subjective. VA is of course >well defined. He just wanted to know when to apply >it. :-) > >Kurt S. > >--- Bradley M Webb wrote: > > > Va, aka maneuvering speed, is not really subjective > > at all............... > > ________________________________ Message 8 _____________________________________ Time: 09:42:13 AM PST US From: "jdmcbean" Subject: RE: Kitfox-List: calculating & subjective Va --> Kitfox-List message posted by: "jdmcbean" The Series 5 was tested to failure as it was being slated for certification. Obviously the certification never happened but that was dollar driven. To see the loading that was happening is scary all by itself. PS.. during the testing, the failure that occurred was not a catastrophic failure but it was determined that the damage was considered structural and therefore the ultimate loading was established and it met with the design parameters established. Fly Safe !! John McBean www.sportplanellc.com "The Sky is not the Limit... It's a Playground" -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of alnanarthur Sent: Thursday, March 02, 2006 10:10 AM Subject: Kitfox-List: calculating & subjective Va --> Kitfox-List message posted by: alnanarthur Bradley, Kurt, Michel and all, When I bought my Kitfox Series 5, Skystar was in it's hayday. They had a bright aeronautical engineer employed at that time. In their lab, I saw an inverted wing set up loaded with sandbags. They said that they had tested the wing to an equivalent load factor of greater than 6 g ultimate. In my Series 5 Operating Handbook on page 2-4 it says: Flight Load Factors (flaps up) --------- +3.8, -1.52 Now if we trust Skystar's design numbers and if we assume that we have not degraded them during the building process then we can calculate Va. The load factor = (V/Vs)squared Therefore Va = squareroot (3.8 ( Vs squared)) For Vs = 45 , Va = 87.7 We, as builders, we can add a subjective factor. Say we want to limit the stress to 2 g. Then again for Vs = 45 and Load factor = 2, Va = 63.6 That is just about Vx for Series 5. To feel what 2g is like do a constant altitude turn at a 60 degree bank, but keep the airspeed above 63.6. The way Va saves the structure is that the wings stall before reaching the limiting load factor. Allan Arthur Kitfox 5, N40AA Rotax 912s, Warpdrive 3 blade Byron Airport (C83) Hanger C8 ________________________________ Message 9 _____________________________________ Time: 10:01:26 AM PST US From: "jdmcbean" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "jdmcbean" Andrew, Yesterday... 2.3 just for the record... The Yellow arc is for smooth air only and even then with caution... The Green arc (Normal operating range) is from Stall clean (Vs1) to maximum structural cruising speed. (this is not Va) Fly Safe !! John McBean www.sportplanellc.com "The Sky is not the Limit... It's a Playground" -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of Andrew Matthaey Sent: Thursday, March 02, 2006 10:18 AM Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Andrew Matthaey" The possibility of exceeding the design limitations of the Kitfox airframe are very rare...You can be completely comfortable bombing through a bit of turbulence here and there at your normal cruise speed. A speed reduction to Va is completely unnecessary. When was the last time turbulence had you pulling well over 2G's? Besides, Va is really only for haevy-pulling, maneuvering flight. If you are worried about stressing the airframe in turbulence, the speed you are interested in is Vno, or normal cruise speed. This is the speed at which, on GA aircraft, the ASI dial gets shaded yellow. It is also known as "turbulent air penetration speed." Just fly below Vno when in turbulence. No need to slow all the way down to Va! Andrew KF3 582 >From: "Bradley M Webb" >To: >Subject: RE: Kitfox-List: calculating Va >Date: Thu, 2 Mar 2006 11:56:32 -0500 > >--> Kitfox-List message posted by: "Bradley M Webb" > >My understanding is that smooth is smooth, no bumps at all. Any bump >(thermals, mountain wave, clear-air turbulence) requires a reduction to Va. >I guess that is subjective, in that minor bumps can probably be ignored, >but >if there's a big one lurking up there... > >I do the same that most others do, I guess. I fly with my hand on the >throttle to keep the airspeed manageable. I'm usually not in a big hurry, >anyway. So reducing to 70mph is no big deal. An in-flight break-up is >second >only to mid-airs on my list of worst ways to die. > >By the time a G-meter tells you the info you're looking for, the wings will >be gone. Again, IF you've exceeded the ultimate load factor (failure). I >think that the reduction to Va is pre-emptive, to prevent the break-up >before it happens. > >It's all about mitigating the risk. >Bradley > >-----Original Message----- >From: owner-kitfox-list-server@matronics.com >[mailto:owner-kitfox-list-server@matronics.com] On Behalf Of kurt schrader >Sent: Thursday, March 02, 2006 11:19 AM >To: kitfox-list@matronics.com >Subject: RE: Kitfox-List: calculating Va > >--> Kitfox-List message posted by: kurt schrader > > >Hi Bradley, > >You missed the point Michel brought up. It is not VA, >but gauging turbulence without a G meter that makes >the degree of turbulence subjective. VA is of course >well defined. He just wanted to know when to apply >it. :-) > >Kurt S. > >--- Bradley M Webb wrote: > > > Va, aka maneuvering speed, is not really subjective > > at all............... > > ________________________________ Message 10 ____________________________________ Time: 10:35:28 AM PST US From: "Fox5flyer" Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Fox5flyer" To all, just for the record. If there's anyone out there who doesn't know what all these V speeds are, just go to the link below. Deke http://www.aviationboom.com/terms/vspeeds.shtml ----- Original Message ----- From: "jdmcbean" Sent: Thursday, March 02, 2006 1:00 PM Subject: RE: Kitfox-List: calculating Va > --> Kitfox-List message posted by: "jdmcbean" > > Andrew, > Yesterday... 2.3 just for the record... > > The Yellow arc is for smooth air only and even then with caution... The > Green arc (Normal operating range) is from Stall clean (Vs1) to maximum > structural cruising speed. (this is not Va) > > Fly Safe !! > John McBean > www.sportplanellc.com > "The Sky is not the Limit... It's a Playground" > > -----Original Message----- > From: owner-kitfox-list-server@matronics.com > [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of Andrew Matthaey > Sent: Thursday, March 02, 2006 10:18 AM > To: kitfox-list@matronics.com > Subject: RE: Kitfox-List: calculating Va > > --> Kitfox-List message posted by: "Andrew Matthaey" > > > The possibility of exceeding the design limitations of the Kitfox airframe > are very rare...You can be completely comfortable bombing through a bit of > turbulence here and there at your normal cruise speed. A speed reduction to > Va is completely unnecessary. When was the last time turbulence had you > pulling well over 2G's? > > Besides, Va is really only for haevy-pulling, maneuvering flight. If you are > worried about stressing the airframe in turbulence, the speed you are > interested in is Vno, or normal cruise speed. This is the speed at which, on > GA aircraft, the ASI dial gets shaded yellow. It is also known as "turbulent > air penetration speed." Just fly below Vno when in turbulence. No need to > slow all the way down to Va! > > Andrew > KF3 582 > > > >From: "Bradley M Webb" > >To: > >Subject: RE: Kitfox-List: calculating Va > >Date: Thu, 2 Mar 2006 11:56:32 -0500 > > > >--> Kitfox-List message posted by: "Bradley M Webb" > > > >My understanding is that smooth is smooth, no bumps at all. Any bump > >(thermals, mountain wave, clear-air turbulence) requires a reduction to Va. > >I guess that is subjective, in that minor bumps can probably be ignored, > >but > >if there's a big one lurking up there... > > > >I do the same that most others do, I guess. I fly with my hand on the > >throttle to keep the airspeed manageable. I'm usually not in a big hurry, > >anyway. So reducing to 70mph is no big deal. An in-flight break-up is > >second > >only to mid-airs on my list of worst ways to die. > > > >By the time a G-meter tells you the info you're looking for, the wings will > >be gone. Again, IF you've exceeded the ultimate load factor (failure). I > >think that the reduction to Va is pre-emptive, to prevent the break-up > >before it happens. > > > >It's all about mitigating the risk. > >Bradley > > > >-----Original Message----- > >From: owner-kitfox-list-server@matronics.com > >[mailto:owner-kitfox-list-server@matronics.com] On Behalf Of kurt schrader > >Sent: Thursday, March 02, 2006 11:19 AM > >To: kitfox-list@matronics.com > >Subject: RE: Kitfox-List: calculating Va > > > >--> Kitfox-List message posted by: kurt schrader > > > > > >Hi Bradley, > > > >You missed the point Michel brought up. It is not VA, > >but gauging turbulence without a G meter that makes > >the degree of turbulence subjective. VA is of course > >well defined. He just wanted to know when to apply > >it. :-) > > > >Kurt S. > > > >--- Bradley M Webb wrote: > > > > > Va, aka maneuvering speed, is not really subjective > > > at all............... > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ________________________________ Message 11 ____________________________________ Time: 10:51:35 AM PST US From: alnanarthur Subject: Re: Kitfox-List: calculating & subjective Va --> Kitfox-List message posted by: alnanarthur John, Do you recall what the design parameters were? At what load factor did they consider the structural damage to have occured? Al Arthur On Mar 2, 2006, at 9:40 AM, jdmcbean wrote: > --> Kitfox-List message posted by: "jdmcbean" > > The Series 5 was tested to failure as it was being slated for > certification. > Obviously the certification never happened but that was dollar > driven. To > see the loading that was happening is scary all by itself. > > PS.. during the testing, the failure that occurred was not a > catastrophic > failure but it was determined that the damage was considered > structural and > therefore the ultimate loading was established and it met with the > design > parameters established. > > Fly Safe !! > John McBean > www.sportplanellc.com > "The Sky is not the Limit... It's a Playground" > ________________________________ Message 12 ____________________________________ Time: 12:28:14 PM PST US From: Michel Verheughe Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: Michel Verheughe Hello Kurt, On Mar 2, 2006, at 12:29 AM, kurt schrader wrote: > In the Fox, I slow down when it scares me. So do I! But I was hoping for a slightly more descriptive experience. It looks like I have opened a can of worms and that people have different meanings. But, first, I never fly without reading METARs and TAFs. If anything is above light turbulence, I don't fly. After all, and unlike you, I don't have to get into that mess to make a living. Incidentally, the Rans S6 of my instructor had a G-meter and when we were practising landings, he used to say: Any landing that moves the needle to 2 Gs is a bad landing. Anyway, thanks everyone for sharing your experience. It is always a pleasure to read you and learn, even if my question wasn't answered as accurately as I was hoping for. Bradley, I also fly, most of the time, with my right hand on the throttle, especially when with a passenger, as my right tight is covered by the kneeboard. An old friend of mine, flying for the first time with me, asked me why I kept my hand on the throttle. I then moved it on his tight and asked: "Would you rather have it like this, darling?" We both had a big laugh! Cheers, Michel do not archive ________________________________ Message 13 ____________________________________ Time: 01:39:10 PM PST US From: "Les James" Subject: Kitfox-List: Landing gear --> Kitfox-List message posted by: "Les James" Does anyone have a Grove landing gear for a model 4 that they want to sell,also a pair of speedster wing tips. Les James Series 5/Rotec ________________________________ Message 14 ____________________________________ Time: 01:59:38 PM PST US From: "Andrew Matthaey" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Andrew Matthaey" 2.3 G's...that's impressive ;-) And in my posting I was attempting to show how the two speeds were in fact different... Andrew >From: "jdmcbean" >To: >Subject: RE: Kitfox-List: calculating Va >Date: Thu, 2 Mar 2006 11:00:45 -0700 > >--> Kitfox-List message posted by: "jdmcbean" > >Andrew, > Yesterday... 2.3 just for the record... > >The Yellow arc is for smooth air only and even then with caution... The >Green arc (Normal operating range) is from Stall clean (Vs1) to maximum >structural cruising speed. (this is not Va) > >Fly Safe !! >John McBean >www.sportplanellc.com >"The Sky is not the Limit... It's a Playground" > >-----Original Message----- >From: owner-kitfox-list-server@matronics.com >[mailto:owner-kitfox-list-server@matronics.com]On Behalf Of Andrew Matthaey >Sent: Thursday, March 02, 2006 10:18 AM >To: kitfox-list@matronics.com >Subject: RE: Kitfox-List: calculating Va > >--> Kitfox-List message posted by: "Andrew Matthaey" > > >The possibility of exceeding the design limitations of the Kitfox airframe >are very rare...You can be completely comfortable bombing through a bit of >turbulence here and there at your normal cruise speed. A speed reduction to >Va is completely unnecessary. When was the last time turbulence had you >pulling well over 2G's? > >Besides, Va is really only for haevy-pulling, maneuvering flight. If you >are >worried about stressing the airframe in turbulence, the speed you are >interested in is Vno, or normal cruise speed. This is the speed at which, >on >GA aircraft, the ASI dial gets shaded yellow. It is also known as >"turbulent >air penetration speed." Just fly below Vno when in turbulence. No need to >slow all the way down to Va! > >Andrew >KF3 582 > > > >From: "Bradley M Webb" > >To: > >Subject: RE: Kitfox-List: calculating Va > >Date: Thu, 2 Mar 2006 11:56:32 -0500 > > > >--> Kitfox-List message posted by: "Bradley M Webb" > > > >My understanding is that smooth is smooth, no bumps at all. Any bump > >(thermals, mountain wave, clear-air turbulence) requires a reduction to >Va. > >I guess that is subjective, in that minor bumps can probably be ignored, > >but > >if there's a big one lurking up there... > > > >I do the same that most others do, I guess. I fly with my hand on the > >throttle to keep the airspeed manageable. I'm usually not in a big hurry, > >anyway. So reducing to 70mph is no big deal. An in-flight break-up is > >second > >only to mid-airs on my list of worst ways to die. > > > >By the time a G-meter tells you the info you're looking for, the wings >will > >be gone. Again, IF you've exceeded the ultimate load factor (failure). I > >think that the reduction to Va is pre-emptive, to prevent the break-up > >before it happens. > > > >It's all about mitigating the risk. > >Bradley > > > >-----Original Message----- > >From: owner-kitfox-list-server@matronics.com > >[mailto:owner-kitfox-list-server@matronics.com] On Behalf Of kurt >schrader > >Sent: Thursday, March 02, 2006 11:19 AM > >To: kitfox-list@matronics.com > >Subject: RE: Kitfox-List: calculating Va > > > >--> Kitfox-List message posted by: kurt schrader > > > > > >Hi Bradley, > > > >You missed the point Michel brought up. It is not VA, > >but gauging turbulence without a G meter that makes > >the degree of turbulence subjective. VA is of course > >well defined. He just wanted to know when to apply > >it. :-) > > > >Kurt S. > > > >--- Bradley M Webb wrote: > > > > > Va, aka maneuvering speed, is not really subjective > > > at all............... > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ________________________________ Message 15 ____________________________________ Time: 02:13:45 PM PST US From: "Bradley M Webb" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Bradley M Webb" Michel, yeah a can of worms, but all in the name of education and safety. I, for one, would like to know whether I am pushing my luck by doing something I'm not supposed to do, maybe because I'd not thought of it, or read the manual, or had no guidance on the proper procedure. Either way, we're all a little more aware of the situation, whether you're right or wrong. Isn't that the real point of a forum such as this? I only grab the thigh if she's real cute (like my better half)! My rule-of-thumb, (applicable in almost all situations, BTW) is that if you've got more hair on your legs than I do, leave it alone! Bradley -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Michel Verheughe Sent: Thursday, March 02, 2006 3:25 PM Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: Michel Verheughe Hello Kurt, On Mar 2, 2006, at 12:29 AM, kurt schrader wrote: > In the Fox, I slow down when it scares me. So do I! But I was hoping for a slightly more descriptive experience. It looks like I have opened a can of worms and that people have different meanings. But, first, I never fly without reading METARs and TAFs. If anything is above light turbulence, I don't fly. After all, and unlike you, I don't have to get into that mess to make a living. Incidentally, the Rans S6 of my instructor had a G-meter and when we were practising landings, he used to say: Any landing that moves the needle to 2 Gs is a bad landing. Anyway, thanks everyone for sharing your experience. It is always a pleasure to read you and learn, even if my question wasn't answered as accurately as I was hoping for. Bradley, I also fly, most of the time, with my right hand on the throttle, especially when with a passenger, as my right tight is covered by the kneeboard. An old friend of mine, flying for the first time with me, asked me why I kept my hand on the throttle. I then moved it on his tight and asked: "Would you rather have it like this, darling?" We both had a big laugh! Cheers, Michel do not archive ________________________________ Message 16 ____________________________________ Time: 02:26:30 PM PST US From: AMuller589@aol.com Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: AMuller589@aol.com you are probably tired of it all by now but I would like to address Vno, something I haven't seen addressed yet. You would need more charts than the company make to find the Va. More important to a pilot is the Vno (maneuvering speed in turbulence). It is the speed you cannot exceed if you intend/need to use full deflection of any flight control surface. Not many documents address this but if you are in severe turbulence (especially the longer period turbulence where you have time to react) you can use full aileron, elevator, rudder deflection if you are at or below maneuvering speed. If the turbulence is less than severe you must use proportionally less control movement if your airspeed is higher than Vno. Attached is the pdf copy of the definitions of turbulence and airspeeds. They are quite clearly defined. I haven't found good references to these yet. I think they are in the design guides. ________________________________ Message 17 ____________________________________ Time: 03:05:22 PM PST US From: Alan & Linda Daniels Subject: Kitfox-List: Va and rudder --> Kitfox-List message posted by: Alan & Linda Daniels I seem to remember that the rudder is a wild card in this Va component. is the speed you cannot exceed if you intend/need to use full deflection of any flight control surface. Not many documents address this but if you are in severe turbulence (especially the longer period turbulence where you have time to react) you can use full aileron, elevator, rudder deflection if you are at or below maneuvering speed. > > > > > > > > > ________________________________ Message 18 ____________________________________ Time: 03:41:22 PM PST US From: "Lowell Fitt" Subject: Re: Kitfox-List: calculating Va (What me worry?) --> Kitfox-List message posted by: "Lowell Fitt" Interesting stuff. I do slow down when the turbulence makes the flying uncomfortable, but for some reason, I'm not particularly concerned about the wings falling off or anything else for that matter. Guys and Gals have been flying these things for years and I would guess well over a million hours total (maybe 2 million) with all levels of builder skills and piloting skills and no inflight structural failures - Wow to that. Lancairs have broken up in flight, but flying through thunder storms would probably break up a Kirfox too. When I was new to my Model IV, turbulence was quite uncomfortable and I'm sure the old adrenaline level reflected that, but after flying a bit (I still prefer still air) I no longer fear for my life if it gets bouncy and try to stay on the ground when it looks dicey.. I get a certain kick out of some of the talk on the Lancair list - guys with an engineering background that insist the $50 electrical connctors are necessary because they are used on the Space Shuttle. I just ordered some $0.50 connectors that were recommended by an avionics shop - who's to say. I think the Kitfox is a fine airplane, well designed and engineered. I guess some day one might fall apart in the air and then we will really have something to talk about. It's fun to learn how others think and it always gives some food for thought, but... This is just one more opinion. Lowell ________________________________ Message 19 ____________________________________ Time: 04:35:31 PM PST US From: alnanarthur Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: alnanarthur Dear AMuller, I believe that you have Va and Vno mixed up. Rod Machado, page B44 states: "The design maneuvering speed (Va) is the speed at which the airplane will stall before exceeding its design limit-load factor in turbulent conditions or when the flight controls are suddenly and fully deflected in flight". My Kitfox Series 5 Pilot Operation Handbook on page 1-10: "Va Maneuvering Speed is the maximum speed at which application of full available aerodymamic control will not overstress the airplane. This is most often used for turbulent air penetration and is not indicated on the airspeed indicator". Also your pdf didn't come thru. Maybe you could copy and paste it into the body of the message. I am going for my BFR soon and all this V speed stuff is good review. Al Arthur On Mar 2, 2006, at 2:25 PM, AMuller589@aol.com wrote: > --> Kitfox-List message posted by: AMuller589@aol.com > > > you are probably tired of it all by now but I would like to address > Vno, > something I haven't seen addressed yet. You would need more charts > than the > company make to find the Va. More important to a pilot is the Vno > (maneuvering > speed in turbulence). It is the speed you cannot exceed if you > intend/need to > use full deflection of any flight control surface. Not many > documents address > this but if you are in severe turbulence (especially the longer > period > turbulence where you have time to react) you can use full aileron, > elevator, rudder > deflection if you are at or below maneuvering speed. If the > turbulence is > less than severe you must use proportionally less control movement > if your > airspeed is higher than Vno. Attached is the pdf copy of the > definitions of > turbulence and airspeeds. They are quite clearly defined. > > I haven't found good references to these yet. I think they are in > the design > guides. > > ________________________________ Message 20 ____________________________________ Time: 05:01:23 PM PST US From: AMuller589@aol.com Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: AMuller589@aol.com I could have mixed these up working with so many files of definitions etc. My original didn't carry the cut/paste picture which was copied from scan0001and pasted into the original text.. I am sending two attachments one is PDF with Turbulence levels defined and another with the Vxxx s defined the second attachment is an expanded set of Vxxx s defined. It states the Va cannot be shown as one number since it depends on weight etc. I have documents on all this and how aircraft are required to be designed with their expected flight and mission environments defined somewhere but may take a while. Also I haven't checked the age of the documents to see if one is older than the other.thanks for the reply Al Muller ________________________________ Message 21 ____________________________________ Time: 06:09:55 PM PST US From: "Rex Shaw" Subject: Kitfox-List: Re roiugh running --> Kitfox-List message posted by: "Rex Shaw" Engine seems to run fine until the auxiliary Facet electric fuel pump is turned on when it appears to become over rich and run rough. But it doesn't happen immediately, just by the end of a high speed run along the runway. Fuel system is according to plans apart from the Facet pump near the header tank. Thoughts are.. 1. the return fuel line to the header tank may be restrictive . i.e. not large enough outlet 2. Just too much fuel pressure. Hi ! Kerry, yes I would suspect too much fuel pressure. Bear in mind if you have the two fuel pumps in series [ the output of the Facet into the input of the mechanical ] the pressures are additive. ie:- if your mecanical pump pumps say 5 PSI and your Facet pump is say 4 PSI then your pressure at the carby is 9 PSI and your carby won't handle that without flooding. Check your manual for carby pressure requirements. It's probably about 6 PSI. If your not sure what pressure you are getting at the carby it really is very easy to simply measure it. Rex. ________________________________ Message 22 ____________________________________ Time: 06:09:55 PM PST US From: "Eric" Subject: Kitfox-List: Poly-Fiber stuff --> Kitfox-List message posted by: "Eric" If anyone has any leftover covering materials ( fabric, reinforcing tapes, chemicals...) I would like to buy them from you as long as the chemicals have not expired their shelf life. Eric ________________________________ Message 23 ____________________________________ Time: 06:09:55 PM PST US From: "Clem Nichols" Subject: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Clem Nichols" I know I'm going to regret posting this as soon as I hit the send button because no one else seems puzzled by the fact that Va decreases as the load decreases. To my non-engineering mind this seems counterintuitive. It seems to me that for a given sized set of wings and support structures the force applied to them would be greater if they were supporting a heavy load and suddenly encountered a very strong updraft or downdraft than if they were supporting a lighter load. As a very primative example, if I tie a one pound rock to a slack length of twine which is tied at the other end to a stationary object, and then throw the rock, it's obviously going to be less likely to break the twine than would a five pound rock similarly thrown. The same thing would apply if I were swinging the rocks in circles above my head. I'm going to be able to swing the small rock faster than the big rock before the string breaks. What am I missing here??? Clem Nichols Do Not Archive ________________________________ Message 24 ____________________________________ Time: 06:14:16 PM PST US From: "jdmcbean" Subject: RE: Kitfox-List: calculating & subjective Va --> Kitfox-List message posted by: "jdmcbean" I don't and I hate to say for sure.. but I seem to remember over 6. It was determined that it would be set as normal category.. 3.8+ 1.52- sustained which allows for the 150% safety margin. Fly Safe !! John McBean www.sportplanellc.com "The Sky is not the Limit... It's a Playground" -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of alnanarthur Sent: Thursday, March 02, 2006 11:50 AM Subject: Re: Kitfox-List: calculating & subjective Va --> Kitfox-List message posted by: alnanarthur John, Do you recall what the design parameters were? At what load factor did they consider the structural damage to have occured? Al Arthur On Mar 2, 2006, at 9:40 AM, jdmcbean wrote: > --> Kitfox-List message posted by: "jdmcbean" > > The Series 5 was tested to failure as it was being slated for > certification. > Obviously the certification never happened but that was dollar > driven. To > see the loading that was happening is scary all by itself. > > PS.. during the testing, the failure that occurred was not a > catastrophic > failure but it was determined that the damage was considered > structural and > therefore the ultimate loading was established and it met with the > design > parameters established. > > Fly Safe !! > John McBean > www.sportplanellc.com > "The Sky is not the Limit... It's a Playground" > ________________________________ Message 25 ____________________________________ Time: 06:17:44 PM PST US From: "wingsdown" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "wingsdown" The string stops being a string sooner with the heavy weight. Rick -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Clem Nichols Sent: Thursday, March 02, 2006 5:49 PM Subject: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Clem Nichols" I know I'm going to regret posting this as soon as I hit the send button because no one else seems puzzled by the fact that Va decreases as the load decreases. To my non-engineering mind this seems counterintuitive. It seems to me that for a given sized set of wings and support structures the force applied to them would be greater if they were supporting a heavy load and suddenly encountered a very strong updraft or downdraft than if they were supporting a lighter load. As a very primative example, if I tie a one pound rock to a slack length of twine which is tied at the other end to a stationary object, and then throw the rock, it's obviously going to be less likely to break the twine than would a five pound rock similarly thrown. The same thing would apply if I were swinging the rocks in circles above my head. I'm going to be able to swing the small rock faster than the big rock before the string breaks. What am I missing here??? Clem Nichols Do Not Archive ________________________________ Message 26 ____________________________________ Time: 07:02:28 PM PST US From: "jdmcbean" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "jdmcbean" Clem, Lets see if we can help... This will be very simplified: We know that the wing stalls at a given angle of attack not airspeed. Is the wing at a higher or lower angle of attack at a higher weight ? Higher the load the greater the angle of attack to maintain level flight. So at cruise flight at gross weight, the wing is already at a higher angle of attack to carry the heavier load and therefore closer to the critical angle of attack. Lightly loaded, the angle of attack on the wing to maintain level flight will be less due to the lighter load and therefore further away from the critical angle of attack. These are just numbers for reference: Lets say the critical angle is 18 degrees and Va is equal to 12 degrees. To maintain level cruise flight, a gross weight loaded aircraft needs to be at 8 degrees... as the load decreases so does this angle to maintain the level cruise flight. So lets say the angle for a lightly loaded aircraft to maintain cruise level flight is 4 degrees. The heavier aircraft needs to fly faster to maintain the 12 degree angle at Va. The lighter aircraft will need to fly slower to maintain the 12 degree angle at Va. Gravity is always there... Hope this makes sense. This is simplified and it is much easier to explain in person. Fly Safe !! John McBean www.sportplanellc.com "The Sky is not the Limit... It's a Playground" -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of Clem Nichols Sent: Thursday, March 02, 2006 6:49 PM Subject: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Clem Nichols" I know I'm going to regret posting this as soon as I hit the send button because no one else seems puzzled by the fact that Va decreases as the load decreases. To my non-engineering mind this seems counterintuitive. It seems to me that for a given sized set of wings and support structures the force applied to them would be greater if they were supporting a heavy load and suddenly encountered a very strong updraft or downdraft than if they were supporting a lighter load. As a very primative example, if I tie a one pound rock to a slack length of twine which is tied at the other end to a stationary object, and then throw the rock, it's obviously going to be less likely to break the twine than would a five pound rock similarly thrown. The same thing would apply if I were swinging the rocks in circles above my head. I'm going to be able to swing the small rock faster than the big rock before the string breaks. What am I missing here??? Clem Nichols Do Not Archive ________________________________ Message 27 ____________________________________ Time: 07:09:21 PM PST US From: alnanarthur Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: alnanarthur Clem, You are quite correct the wings are stressed less at when the aircraft is lightly loaded but they can accelerate the lightly loaded aircraft more. This puts more stress on the engine mount (which is attempting to keep the engine from departing from the nose of the aircraft) the seat and the baggage compartment. Hope this helps. This was explained to me by the bright young aeronautical engineer at Skystar when I asked him the same question. Al Arthur On Mar 2, 2006, at 6:19 PM, wingsdown wrote: > --> Kitfox-List message posted by: "wingsdown" > > The string stops being a string sooner with the heavy weight. > > Rick > > -----Original Message----- > From: owner-kitfox-list-server@matronics.com > [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Clem > Nichols > Sent: Thursday, March 02, 2006 5:49 PM > To: kitfox list > Subject: Kitfox-List: calculating Va > > > --> Kitfox-List message posted by: "Clem Nichols" > > I know I'm going to regret posting this as soon as I hit the send > button > because no one else seems puzzled by the fact that Va decreases as the > load decreases. To my non-engineering mind this seems > counterintuitive. > It seems to me that for a given sized set of wings and support > structures the force applied to them would be greater if they were > supporting a heavy load and suddenly encountered a very strong updraft > or downdraft than if they were supporting a lighter load. As a very > primative example, if I tie a one pound rock to a slack length of > twine > which is tied at the other end to a stationary object, and then throw > the rock, it's obviously going to be less likely to break the twine > than > would a five pound rock similarly thrown. The same thing would > apply if > I were swinging the rocks in circles above my head. I'm going to be > able to swing the small rock faster than the big rock before the > string > breaks. What am I missing here??? > > Clem Nichols > Do Not Archive > > ________________________________ Message 28 ____________________________________ Time: 07:40:16 PM PST US From: "Clem Nichols" Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Clem Nichols" John: Thanks for your reply. I think I'm beginning to see the light. Va is not an absolute speed, but the speed at which the plane will stall before structural damage occurs, and obviously the heavier plane will stall at a slower absolute speed than the lighter one. It's apparently where one thing counteracts the other. I had in mind a situation last winter when a farm hand of mine was feeding a 1500 pound roll of hay on a tractor-mounted hayfork. The ground was frozen hard, and when he drove over a rut which had been created when the ground was muddy, the back wheels dropped down into the rut, and snapped the spear off the hayfork. If he had been going more slowly, this would not have happened. By the same token, if he had been carrying a 100 pound roll of hay at the same speed or if he had been carrying the heavy roll more slowly it wouldn't have happened. What this thinking doesn't take into account, obviously, is the "stall speed" of the tractor. :-) Clem Nichols Do Not Archive ----- Original Message ----- From: "jdmcbean" Sent: Thursday, March 02, 2006 9:00 PM Subject: RE: Kitfox-List: calculating Va > --> Kitfox-List message posted by: "jdmcbean" > > Clem, > Lets see if we can help... > > This will be very simplified: We know that the wing stalls at a given > angle > of attack not airspeed. > > Is the wing at a higher or lower angle of attack at a higher weight ? > Higher the load the greater the angle of attack to maintain level flight. > > So at cruise flight at gross weight, the wing is already at a higher angle > of attack to carry the heavier load and therefore closer to the critical > angle of attack. > > Lightly loaded, the angle of attack on the wing to maintain level flight > will be less due to the lighter load and therefore further away from the > critical angle of attack. > > These are just numbers for reference: Lets say the critical angle is 18 > degrees and Va is equal to 12 degrees. To maintain level cruise flight, a > gross weight loaded aircraft needs to be at 8 degrees... as the load > decreases so does this angle to maintain the level cruise flight. So lets > say the angle for a lightly loaded aircraft to maintain cruise level > flight > is 4 degrees. > > The heavier aircraft needs to fly faster to maintain the 12 degree angle > at > Va. The lighter aircraft will need to fly slower to maintain the 12 degree > angle at Va. > > Gravity is always there... Hope this makes sense. This is simplified > and > it is much easier to explain in person. > > > Fly Safe !! > John McBean > www.sportplanellc.com > "The Sky is not the Limit... It's a Playground" > > -----Original Message----- > From: owner-kitfox-list-server@matronics.com > [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of Clem Nichols > Sent: Thursday, March 02, 2006 6:49 PM > To: kitfox list > Subject: Kitfox-List: calculating Va > > --> Kitfox-List message posted by: "Clem Nichols" > > I know I'm going to regret posting this as soon as I hit the send button > because no one else seems puzzled by the fact that Va decreases as the > load > decreases. To my non-engineering mind this seems counterintuitive. It > seems to me that for a given sized set of wings and support structures the > force applied to them would be greater if they were supporting a heavy > load > and suddenly encountered a very strong updraft or downdraft than if they > were supporting a lighter load. As a very primative example, if I tie a > one > pound rock to a slack length of twine which is tied at the other end to a > stationary object, and then throw the rock, it's obviously going to be > less > likely to break the twine than would a five pound rock similarly thrown. > The same thing would apply if I were swinging the rocks in circles above > my > head. I'm going to be able to swing the small rock faster than the big > rock > before the string breaks. What am I missing here??? > > Clem Nichols > Do Not Archive > > > ________________________________ Message 29 ____________________________________ Time: 07:44:21 PM PST US From: "Jay Carter" Subject: Kitfox-List: Gone West --> Kitfox-List message posted by: "Jay Carter" List, The March issue of Sport Aviation gone west list has Victor Jacko, Seguine,Tx. listed. If this has been mentioned on the Kitfox list I missed it. Jay C. ________________________________ Message 30 ____________________________________ Time: 07:48:37 PM PST US From: "Bradley M Webb" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "Bradley M Webb" Speaking of the motor mount, I had heard that Sean Tuckers Bi-plane was G limited only by the motor mount. Otherwise, I guess even he couldn't break the airframe. When pondering, don't forget the whole airframe, not just the wings. Bradley -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of alnanarthur Sent: Thursday, March 02, 2006 10:09 PM Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: alnanarthur Clem, You are quite correct the wings are stressed less at when the aircraft is lightly loaded but they can accelerate the lightly loaded aircraft more. This puts more stress on the engine mount (which is attempting to keep the engine from departing from the nose of the aircraft) the seat and the baggage compartment. Hope this helps. This was explained to me by the bright young aeronautical engineer at Skystar when I asked him the same question. Al Arthur On Mar 2, 2006, at 6:19 PM, wingsdown wrote: > --> Kitfox-List message posted by: "wingsdown" > > The string stops being a string sooner with the heavy weight. > > Rick > > -----Original Message----- > From: owner-kitfox-list-server@matronics.com > [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Clem > Nichols > Sent: Thursday, March 02, 2006 5:49 PM > To: kitfox list > Subject: Kitfox-List: calculating Va > > > --> Kitfox-List message posted by: "Clem Nichols" > > I know I'm going to regret posting this as soon as I hit the send > button > because no one else seems puzzled by the fact that Va decreases as the > load decreases. To my non-engineering mind this seems > counterintuitive. > It seems to me that for a given sized set of wings and support > structures the force applied to them would be greater if they were > supporting a heavy load and suddenly encountered a very strong updraft > or downdraft than if they were supporting a lighter load. As a very > primative example, if I tie a one pound rock to a slack length of > twine > which is tied at the other end to a stationary object, and then throw > the rock, it's obviously going to be less likely to break the twine > than > would a five pound rock similarly thrown. The same thing would > apply if > I were swinging the rocks in circles above my head. I'm going to be > able to swing the small rock faster than the big rock before the > string > breaks. What am I missing here??? > > Clem Nichols > Do Not Archive > > ________________________________ Message 31 ____________________________________ Time: 08:02:30 PM PST US From: "jdmcbean" Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: "jdmcbean" Al, You must have been speaking with Dave Snell.. Great guy.. Although the aircraft wings are supporting a lighter load.. say 1 pilot, low fuel, no baggage etc... The engine mount is still carrying the same weight... FYI.. The engine mount, baggage area even the horizontal tail surface was load tested. Fly Safe !! John McBean www.sportplanellc.com "The Sky is not the Limit... It's a Playground" -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com]On Behalf Of alnanarthur Sent: Thursday, March 02, 2006 8:09 PM Subject: Re: Kitfox-List: calculating Va --> Kitfox-List message posted by: alnanarthur Clem, You are quite correct the wings are stressed less at when the aircraft is lightly loaded but they can accelerate the lightly loaded aircraft more. This puts more stress on the engine mount (which is attempting to keep the engine from departing from the nose of the aircraft) the seat and the baggage compartment. Hope this helps. This was explained to me by the bright young aeronautical engineer at Skystar when I asked him the same question. Al Arthur On Mar 2, 2006, at 6:19 PM, wingsdown wrote: > --> Kitfox-List message posted by: "wingsdown" > > The string stops being a string sooner with the heavy weight. > > Rick > > -----Original Message----- > From: owner-kitfox-list-server@matronics.com > [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Clem > Nichols > Sent: Thursday, March 02, 2006 5:49 PM > To: kitfox list > Subject: Kitfox-List: calculating Va > > > --> Kitfox-List message posted by: "Clem Nichols" > > I know I'm going to regret posting this as soon as I hit the send > button > because no one else seems puzzled by the fact that Va decreases as the > load decreases. To my non-engineering mind this seems > counterintuitive. > It seems to me that for a given sized set of wings and support > structures the force applied to them would be greater if they were > supporting a heavy load and suddenly encountered a very strong updraft > or downdraft than if they were supporting a lighter load. As a very > primative example, if I tie a one pound rock to a slack length of > twine > which is tied at the other end to a stationary object, and then throw > the rock, it's obviously going to be less likely to break the twine > than > would a five pound rock similarly thrown. The same thing would > apply if > I were swinging the rocks in circles above my head. I'm going to be > able to swing the small rock faster than the big rock before the > string > breaks. What am I missing here??? > > Clem Nichols > Do Not Archive > > ________________________________ Message 32 ____________________________________ Time: 10:46:49 PM PST US From: "Lowell Fitt" Subject: Re: Kitfox-List: Re roiugh running --> Kitfox-List message posted by: "Lowell Fitt" I think I finally get the picture. I rebuilt my carburetors at about 600 hours per recommendations. The first thing I noticed was that after a flight and taxiing back home, I would get rough running and eventually fuel spilling from the vent lines. I rechecked everything - float level, etc and determined it was the float needles leaking. I called Bing for soem advice and was told there were three needles for the Bing CV ccarbs. The black one for the ULS, The brass one for the UL and, I believe a white one for ??. I had the right needles, but they were leaking. I went back to the old needle in the worst of the two carbs and flew with that for a year, then finally went back to the original on the other side last month during the Annual Condition Inspection - much smoother idle. Incidentally, by the inspection criteria noted in the maint manual, the old ones were perfectly servicable and that after the 600 hours. Moral of this story, I think Bing has problems from time to time with this part. Regards, Lowell ----- Original Message ----- From: "Rex Shaw" Sent: Friday, March 03, 2006 12:25 PM Subject: Kitfox-List: Re roiugh running > --> Kitfox-List message posted by: "Rex Shaw" > > Engine seems to run fine until the auxiliary Facet electric fuel pump is > turned on when it appears to become over rich and run rough. But it > doesn't > happen immediately, just by the end of a high speed run along the runway. > Fuel system is according to plans apart from the Facet pump near the > header > tank. Thoughts are.. > > 1. the return fuel line to the header tank may be restrictive . i.e. not > large enough outlet > 2. Just too much fuel pressure. > > Hi ! Kerry, > yes I would suspect too much fuel pressure. Bear in mind if > you have the two fuel pumps in series [ the output of the Facet into the > input of the mechanical ] the pressures are additive. ie:- if your > mecanical pump pumps say 5 PSI and your Facet pump is say 4 PSI then your > pressure at the carby is 9 PSI and your carby won't handle that without > flooding. Check your manual for carby pressure requirements. It's probably > about 6 PSI. > If your not sure what pressure you are getting at the carby it really is > very easy to simply measure it. > > Rex. > > > ________________________________ Message 33 ____________________________________ Time: 11:12:05 PM PST US From: kurt schrader Subject: RE: Kitfox-List: Baggage compartment --> Kitfox-List message posted by: kurt schrader Probably just me, but it is the baggage floor on those tiny little weld mounts just above the elevator push rod that bothers me the most when I am loaded anywhere near 150 lbs. 3.8 x 150 = 570 lbs. Sure the baggage fabric carries some of the load to its mounts, but those tiny weldments..... Just wish I added a few extra braces for peace of mind, I suppose. Did anyone ever do that? Kurt S. S-5 Do not archive --- jdmcbean wrote: > ...................... > FYI.. The engine mount, baggage area even the > horizontal tail surface was load tested. > > Fly Safe !! > John McBean > www.sportplanellc.com > "The Sky is not the Limit... It's a Playground" ________________________________ Message 34 ____________________________________ Time: 11:50:59 PM PST US From: kurt schrader Subject: RE: Kitfox-List: calculating Va --> Kitfox-List message posted by: kurt schrader Clem, Never a bad question. Some of us skin a cat front to back, some back to front. If John's example didn't go your direction, try this one. (Mom always said I was a bit backward) Suppose a plane has a gross weight of 1000 lbs. At X speed it can just lift 3.8 G's or 3,800 lbs before stalling. So X = VA speed at gross weight. If you loaded the plane to only 760 lbs and flew it at the same X speed, it could still lift 3,800 lbs, but that would take 5 G's to reach 3,800 lbs of lift and stall it. WT G's Wing load 1000 x 3.8 = 3,800 lbs 760 x 5 = 3,800 lbs The lighter the weight, the more G's you can pull at the same speed and it is the G's that cause the overload because the engine (and you, etc) still weigh the same. So you have to slow down to keep from exceeding 3.8 G's before stalling at lower weights. 760 lbs x 3.8 G's = 2,888 lbs of lift At 760 lbs, you need to slow down so that your wing can only generate 2,888 lbs of lift before stalling or you can exceed 3.8 G's. >From this you should see that it is not the wings that will fail on a Fox. They can lift gross weight at the designed G limit. But the other components can exceed their G'limit before the wings stall, let alone fail, at below gross weight, or higher than VA speeds. Likewise in the rock and string example, the lighter rock (plane) can be spun to a higher G limit before the string (wing) breaks. The G limit of the rock, not the string is the limiting factor. Hope that helps because simple is all I can do anymore. ;-) Kurt S. S-5 --- jdmcbean wrote: > Clem, > Lets see if we can help........... > > This will be very simplified: We know that the wing > stalls at a given angle of attack not airspeed...... > > Fly Safe !! > John McBean > www.sportplanellc.com > "The Sky is not the Limit... It's a Playground"