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franicaza(at)yahoo.com.mx
Guest

Posted: Mon Jun 18, 2007 1:04 pm Post subject: Nose wheel and weight & balance for Classic IV

List,



I have converted my classic IV into a nose wheel. I´ve

flown it twice and it has been quite difficult to make

the flair before main wheels touch the ground(Grove

landing gear). 



Just two questions:



1. Has someone noticed that after makeing the nose

wheel conversion?



2. Where can I get the plot to calculate Weight & 

balance? My manual has just the tail dragger option.



Thanks in advance,

Francisco Icaza

Classic IV Rotax 912-S

Mexico City.



	

	

		

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wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Mon Jun 18, 2007 3:16 pm Post subject: Re: Nose wheel and weight & balance for Classic IV

What makes you think the W&B plots would be different for tail dragger vs tri gear? The plane doesn't know the difference when it's in the air right?

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

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Jun 18, 2007 4:31 pm Post subject: Nose wheel and weight & balance for Classic IV

Luis,



Actually, I think the airplane would know the difference.  a big bunch of 

weight in the nose gear under the engine, no tail wheel eleven feet back and 

the aft positioned maingear would definitely alter the CG - nice to know 

where it actually is and and if it is still in the envelope.  From the post, 

it sounds like it has moved forward a bit.



I think he is asking if anyone has the arm lengths for the aft positioned 

landing gear and the new nose wheel out front for the re-weighing 

calculations and the form for plugging in all the numbers.



Lowell Fitt

Cameron Park, CA

Model IV-1200 R-912 UL Warp

1998 870 hrs.

---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Jun 18, 2007 4:38 pm Post subject: Nose wheel and weight & balance for Classic IV

Icaza:



Re-weigh the plane.



The arm  for the datum to the nosewheel will be considered negative. After that the  calculations are pretty similar to the conventional  gear.



E.g.

                   Weight    dist           arm

Nose  wheel 100lb. (at) -30" = - 3000in lb

Left main    275lb. (at)   20" =    5500in. lb.

Right main  280lb  (at)  20"  =    5600in. lb.

Weight        655lb.   (at)               5600 + 5500 - 3000 = 8100inlb



8100in.lb./655lb. = 12.36"



In this  example the CG is 12.36" aft of the datum



The figures I used in this  example do not reflect the weighed values of any particular aircraft.  I  pulled them and the distances from the datum out of thin  air.  

  

[img]cid:742343600(at)19062007-1B51[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 Do not archive

 



 



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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Jun 18, 2007 4:51 pm Post subject: Nose wheel and weight & balance for Classic IV

The arms of both the mains and the nose over the  tail have moved.... You better believe the CG is moved.  Also consider the  weight of the nose gear as opposed to the tail wheel.  Once the CG is  calculated the corrections for loading/fuel will be exactly as before.  CG  is one of the important changes when ever you change gear  configuration.

 

[img]cid:057024900(at)19062007-1B58[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 Do not archive

 

  

 

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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Jun 18, 2007 4:58 pm Post subject: Nose wheel and weight & balance for Classic IV

Lowell:



 I think the datum on my plane  is the leading edge of the wing.  All he needs t0o do is drop a plumb bob  from there ands measure the linear distance to the nose wheel and then back to  the mains.  He should re-weigh the plane.



 

[img]cid:054185600(at)19062007-1B5F[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 Do not archive

 

 

 



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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Mon Jun 18, 2007 5:34 pm Post subject: Re: Nose wheel and weight & balance for Classic IV

 	  Quote: 	
		  Actually, I think the airplane would know the difference. a big bunch of 

weight in the nose gear under the engine, no tail wheel eleven feet back and 

the aft positioned maingear would definitely alter the CG - nice to know 

where it actually is and and if it is still in the envelope. From the post, 

it sounds like it has moved forward a bit. 



I think he is asking if anyone has the arm lengths for the aft positioned 

landing gear and the new nose wheel out front for the re-weighing 

calculations and the form for plugging in all the numbers. 	




That's not what I meant. In the original post, Francisco mentioned that he has the manual which has W&B procedures for the tail dragger configuration. I'm just pointing out that the same manual applys for the nose wheel configuration. Of course, his balance has changed. In fact, given his inability to flair on landing, I'd say he's flying very nose heavy. But the aerodynamics haven't changed so same procedures apply and the datum plane hasn't moved.

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

franicaza(at)yahoo.com.mx
Guest

Posted: Mon Jun 18, 2007 6:31 pm Post subject: Nose wheel and weight & balance for Classic IV

Luis,



My concern is that I moved several weights that

obviously could change the balance of my plane during

flight. I changed the front welded main gear for the

heavier Grove landing gear, now in the aft position.

As well the nose gear is much more heavier than the

tail wheel (but much closer to the C.G.), and so on. I

also suppose that it was calculated by SkyStar and by

Kitfox Aircraft. I just want to know how I can

calculate weight & balance again with that

configuration. It´s as well mandatory for DGAC

(Mexican FAA) for anyone that made those changes.



Thanks,



Francisco Icaza.

Classic IV Rotax 912-S

Mexico City.



 

--- wingnut <wingnut(at)spamarrest.com> escribió:



 	  Quote: 	
		   

 <wingnut(at)spamarrest.com>

 

 What makes you think the W&B plots would be

 different for tail dragger vs tri gear? The plane

 doesn't know the difference when it's in the air

 right?

 

 --------

 Luis Rodriguez

 Model IV 1200

 Rotax 912UL

 Flying Weekly

 Laurens, SC (34A)

 

 

 

 

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http://forums.matronics.com/viewtopic.php?p=119241#119241
	


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wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Mon Jun 18, 2007 7:20 pm Post subject: Re: Nose wheel and weight & balance for Classic IV

 	  Quote: 	
		  My concern is that I moved several weights that

obviously could change the balance of my plane during

flight. 	


Yes, the weights have moved. The procedure to find your new center of gravity is the same. You stick a scale under each wheel, and multiply the weight at each with its distance from the leading edge of the main wing (as Noel pointed out, the distance is negative for the nose gear). There's even an example in the manual. The only difference for you is that all the distances have changed but you just have to measure it like Noel suggested. You can even use the same chart showing the CG limits at different take off weights. 



I wouldn't fly the airplane until this is sorted out one way or the other. You're probably way past the forward cg limit right now.

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

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Jun 19, 2007 5:00 am Post subject: Nose wheel and weight & balance for Classic IV

You're spot-on Luis.  My misunderstanding of  your comments.



The only difference is the arm for the nose wheel will be  negative ( datum between the nose and mains).  You are also correct in  saying the plane won't really care as long as the CG is within limits.



If  there is a problem with the plane flying straight an level it may be best to  have a heart to heart with it and it should be told in the strongest terms to,  "Fly right!"  

 

[img]cid:625354612(at)19062007-2C83[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 Do not archive

 

  

 



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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

kitfoxmike

Joined: 05 Dec 2006
Posts: 373

Posted: Tue Jun 19, 2007 5:46 am Post subject: Re: Nose wheel and weight & balance for Classic IV

I am surprised that you actually flew the plan without reduing the weight and balance.  Now with that said, I agree, you need to do the math.  And to make sure you have it right and you believe you found the center of gravity, take and jack the plane off the wheels at the point you believe the CG is at.  The plane better balance, not drop at the front or back.  My feeling is you are too nose heavy, and until you get some weight shifted to the rear, you will not be able to properly flair to land.  Good luck and fly safe.  Of course the jacking and double checking the CG is optional, so is doing a  check of the engine and airframe before flight.  After all, you are only above ground when flying, and It's not too far down to the ground, or is it???

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Jun 19, 2007 7:27 am Post subject: Nose wheel and weight & balance for Classic IV

Mike:

They say you should learn something new  everyday.  Today is definitely no exception. 



You referred to  jacking a plane up at the suspected CG...  This sounds useful if you can  tell me how.  There are no hard points on my plane any where near the  CG.  Lifting by the chines probably won't work either because the CG will  be above the jacking point and won't balance there either.    

We used to lift float planes off the dolly in the  hangar using an overhead crane and a special spreader bar which attached to  either the wing attach points or specially installed lifting rings.  I  always found it was easier to lift if I calculated the CG before starting the  lift.  of course when you took the plane off the floats the CG changed  dramatically but with the use of a couple of guy ropes I was able to single  handed change from flats to wheels....  going the other way (installing  floats) required more help and a dictionary of four letter  words! 

The last two times I put my 'Fox on floats I  lifted it from the rafters in the garage using three points and three small  block and tackle.  Using that set up knowing the CG before starting  wouldn't have helped at all.



The only way I can see to find the CG is by  mathematical calculation... Level the plane, weigh the muggly ugger and jump  head first into the math.  If you think you've messed up get someone to  check your measurements and/or math...  I'm sure there are enough people  who would be happy to do that.



 

[img]cid:972410615(at)19062007-2C8A[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 Do not archive

 

 

 

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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

kitfoxmike

Joined: 05 Dec 2006
Posts: 373

Posted: Tue Jun 19, 2007 9:07 am Post subject: Re: Nose wheel and weight & balance for Classic IV

Not having done this on a fox, here is an  example of trying.  Take the doors off and run a strap through the fuse and out to the tips and the up to a lift in the rafters, since the cg would more than likely be in that area, I think generally 12 inches back from the front of the wing, but just guessing right now, need to check the paper work in my plane.  I suppose you could lift right at the rib at the tips. I've lifted one side for installing a scale in this location when putting the scale under the wheel when I did weight and balance. 



I build RC airplanes and fly them, been doing this since 1991.  I found it pretty convenient to have a span from the factory where the cg was and made sure that the model balanced before flying them and this is how we did it, lift at the cg.  On the nose wheel planes I would put the cg as far back(tail heavy) as I could and then when landing I would hold the nose off the ground all the way back to the pits.  Really impressed a lot of people.  After all most never made the runway, they ended up in the grass, and here I was landing on center line and taxi with the front wheel off the ground.

klschooley(at)hotmail.com
Guest

Posted: Tue Jun 19, 2007 9:30 am Post subject: Nose wheel and weight & balance for Classic IV

A few things to remember, a new weight and balance is easy to compute, safe 

flying (and landing) require a balanced aircraft, and the FAA requires a 

current weight and balance to be aboard the acft.

                                                                          

Happy and safe flying, Ken



 	  Quote: 	
		  From: "kitfoxmike" <customtrans(at)qwest.net>

Reply-To: kitfox-list(at)matronics.com

To: kitfox-list(at)matronics.com

Subject: Re: Nose wheel and weight & balance for Classic IV

Date: Tue, 19 Jun 2007 06:46:19 -0700






I am surprised that you actually flew the plan without reduing the weight 

and balance.  Now with that said, I agree, you need to do the math.  And to 

make sure you have it right and you believe you found the center of 

gravity, take and jack the plane off the wheels at the point you believe 

the CG is at.  The plane better balance, not drop at the front or back.  My 

feeling is you are too nose heavy, and until you get some weight shifted to 

the rear, you will not be able to properly flair to land.  Good luck and 

fly safe.  Of course the jacking and double checking the CG is optional, so 

is doing a  check of the engine and airframe before flight.  After all, you 

are only above ground when flying, and It's not too far down to the ground, 

or is it???



--------

kitfoxmike

model IV, 1200

speedster

912ul

building

RV7a

slowbuild wings, fuse, finish kit

&quot;if you're not getting razzed from pilots or the FAA then you're not 

flying enough&quot;

Do not archive





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=119370#119370






	


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josandt(at)verizon.net
Guest

Posted: Tue Jun 19, 2007 11:43 am Post subject: Nose wheel and weight & balance for Classic IV

I'm going to show my ignorance here. Since the wheels are always located a set distance fore and aft, why can't one simply calculate weight and balance by examining relative weights on the wheels? Why can't you just put scales under all the wheels, then say nose wheel weight must not exceed a certain percentage of total weight to remain inside CG envelope? I know I'm probably missing something here (this being my first build), but what is it? 



John Sandt / KF7 / Trigear / Corvair / BRS / Ridgecrest, CA (land of fruits and nuts) 



<<Subject: RE: Re: Nose wheel and weight & balance for <<Classic IV<<The only way I can see to find the CG is by mathematical <<calculation... Level the plane, weigh the muggly ugger and jump <<head first into the math.Ã‚Â

propellerdesign(at)tele2.
Guest

Posted: Tue Jun 19, 2007 12:12 pm Post subject: Nose wheel and weight & balance for Classic IV

Sure you can do it this way, (this is the normal  way)

 just make sure that the plane is in the correct  angle it should be weighted.

  

 Jan

 [quote]   ---

wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Tue Jun 19, 2007 12:18 pm Post subject: Re: Nose wheel and weight & balance for Classic IV

 	  Quote: 	
		  I'm going to show my ignorance here. Since the wheels are always located a set distance fore and aft, why can't one simply calculate weight and balance by examining relative weights on the wheels? Why can't you just put scales under all the wheels, then say nose wheel weight must not exceed a certain percentage of total weight to remain inside CG envelope? I know I'm probably missing something here (this being my first build), but what is it? 	




How do you figure out that percentage? Also, are you going to drive the kitfox up on scales every time your take off weight changes or a passenger brings some luggage? If you follow the procedure detailed in the manual (and summerised by Noel earlier) then you can figure any changes to your CG with just a little math. It's really very easy.

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

josandt(at)verizon.net
Guest

Posted: Tue Jun 19, 2007 1:00 pm Post subject: Nose wheel and weight & balance for Classic IV

Weight on front wheel divided by total vehicle weight is a VERY simple fraction that even a small child can do. It's only one operation on a simple calculator (something even I can do!). And since ALL Kitfoxes of the same model should share these weight proportions, it would be very easy for comparison. I'm not suggesting that formal weight and balance should be shortcut, only that it might be a very simple matter to determine what part of the envelope one was operating in (no slide rule and measuring tape required). No slings, jacks, fulcrums, nuclear reactors, or atom smashers. Is it actually "the normal method" as another kitfox lister has said? 

John Sandt/KF7/Tri/BRS/Corvair/Ridgecrest,CA

From: wingnut <wingnut(at)spamarrest.com>

Date: 2007/06/19 Tue PM 03:18:24 CDT

To: kitfox-list(at)matronics.com

Subject: Re: Nose wheel and weight & balance for Classic IV

 	  Quote: 	
		   I'm going to show my ignorance here. Since the wheels are always located a set distance fore and aft, why can't one simply calculate weight and balance by examining relative weights on the wheels? Why can't you just put scales under all the wheels, then say nose wheel weight must not exceed a certain percentage of total weight to remain inside CG envelope? I know I'm probably missing something here (this being my first build), but what is it? 

How do you figure out that percentage? Also, are you going to drive the kitfox up on scales every time your take off weight changes? If you follow the procedure detailed in the manual (and summerised by Noel earlier) then you can figure any changes to your CG with just a little math. It's really very easy.

--------

Luis Rodriguez

Model IV 1200

Rotax 912UL

Flying Weekly

Laurens, SC (34A)

Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=119491#119491

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Tue Jun 19, 2007 1:37 pm Post subject: Re: Nose wheel and weight & balance for Classic IV

Francisco,

The old Skystar company built and flew a version of the classic 4 with a nose wheel option before they went out of business.  It was called the "Lite Squared".  While the Center of gravity envelope is most likely the same as the Classic 4, they probably did some flight testing to confirm the CG envelope and loading limits for that plane.  It might be worth your time to contact Kitfox Aircraft LLC http://www.kitfoxaircraft.com/  and ask if they have the weight and balance forms and instructions for weighing that model and computing the empty CG.

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Jun 19, 2007 2:40 pm Post subject: Nose wheel and weight & balance for Classic IV

You could do it that way... Only as long as the  weight on the mains don't change.  If you did it that way your W&B  wouldn’t match legislated specs and you could be the only one who would know if  the plane was ever in balance. 



The aircraft are considered to be  balanced by the location of the Centre of Gravity (CG)along the length of the  aircraft. (longitudinal axis).   Airplanes are given an operating  envelope for the CG by their designers.  Determining exactly where the  empty CG is is one of those things you will have to calculate before the first  flight.  Then in the interests of good airmanship it is recommended that  you do another W&B before every flight including things like the amount of  fuel carried and the weight of pilots, passengers and sundry fishing/camping  gear .  All this is done through simple arithmetic.  The only time  the aircraft may need to be weighed is when the first empty weight CG is  calculated.



The calculation of the location of the CG is made with the  use of a Datum line.  The datum line is just a reference point from which  to make the measurements along the longitudinal axis of the airplane.  Some  planes have the datum so many inches in front of the nosewheel, some at the fire  wall and some at the leading edge of the wing.  I think there is one (C172  ?) that has the datum at the front of the spinner.



 

[img]cid:625183822(at)19062007-3446[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 

 

 

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Kitfox III-A
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