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n4546v(at)mindspring.com
Guest

Posted: Mon Aug 20, 2007 1:38 pm Post subject: weight & balance with one scale?

This is probably a Rookie question and is only for  discussion as I have access to three scales, but if one wanted, could you  correctly weigh an airplane with just one scale if you put scale height blocks  under the other wheels as you moved the scale from wheel to wheel?  First  glance is that it would weigh correctly as long as the other wheels are at the  constant height.  Not very convenient though.

  

 Regards,

  

 Randy, Las Vegas

   [quote][b]

dredmoody(at)cox.net
Guest

Posted: Mon Aug 20, 2007 1:49 pm Post subject: weight & balance with one scale?

As far as I know, Randy, you are correct.



Dred



---- "Randy L. Thwing" <n4546v(at)mindspring.com> wrote: 

could you correctly weigh an airplane with just one scale if you put scale height blocks under the other wheels as you moved the scale from wheel to wheel?

vgstol(at)bigpond.net.au
Guest

Posted: Mon Aug 20, 2007 2:03 pm Post subject: weight & balance with one scale?

Yes, definitely can use just one  scale, but don't just lift the aircraft to change from block to scale - the  landing gear will flex and put a side load on the scale as the weight comes on  it.  Just need  more blocks so that you can roll the  aircraft on and off the scale.

  

 Tailwinds always,

 JG

 [quote]   ---

larry(at)macsmachine.com
Guest

Posted: Mon Aug 20, 2007 2:07 pm Post subject: weight & balance with one scale?

Randy,

You'd be better to have 4 scales and rotate one out with each wheel to 

check the accuracy of each as you go.  I found four 300 lb scales at 

$9.00 each

on sale and then made a lever-lift that picks up each wheel with little 

effort as scales are slid under and out.  You need a 1/4 inch thick 6 x 

6 of aluminum to spread the

weight on each scale, but it works and is convenient. Takes about 15 

minutes to do a W & B. The back link drops out for removal.

http://www.macsmachine.com/images/tjh/winghandling/full/scaleinsert.gif

http://www.macsmachine.com/images/tjh/winghandling/full/scaleplaced.gif

http://www.macsmachine.com/images/tjh/winghandling/full/scalew&b.gif

.good luck,



Larry McFarland 601HDS at www.macsmachine.com



Randy L. Thwing wrote:

 	  Quote: 	
		   This is probably a Rookie question and is only for discussion as I 

 have access to three scales, but if one wanted, could you correctly 

 weigh an airplane with just one scale if you put scale height blocks 

 under the other wheels as you moved the scale from wheel to wheel?  

 First glance is that it would weigh correctly as long as the other 

 wheels are at the constant height.  Not very convenient though.

  

 Regards,

  

 Randy, Las Vegas

leinad

Joined: 19 Sep 2006
Posts: 283
Location: Central Virginia

Posted: Mon Aug 20, 2007 3:26 pm Post subject: Re: weight & balance with one scale?

One small detail worth mentioning.  If you are also determining ballance, the plane ought to be in the horizontal flight attitude with the top longeron level when weighing.  Then you can calculate the moments to the datum with no problem.  

Dan Dempsey[/quote]

_________________
Scratch building XL with Corvair Engine

pmaxpmax(at)HOTMAIL.COM
Guest

Posted: Mon Aug 20, 2007 3:46 pm Post subject: weight & balance with one scale?

That's how I did mine.

  

 Do Not Archive



Phil Maxson

 601XL/Corvair

 Northwest New Jersey

  	  Quote: 	
		    From: n4546v(at)mindspring.com

Subject: weight & balance with one scale?

Date: Mon, 20 Aug 2007 14:37:27 -0700



     This is probably a Rookie question and is only for discussion as I have access to three scales, but if one wanted, could you correctly weigh an airplane with just one scale if you put scale height blocks under the other wheels as you moved the scale from wheel to wheel?  First glance is that it would weigh correctly as long as the other wheels are at the constant height.  Not very convenient though.

  

 Regards,

  

 Randy, Las Vegas

	
Discover the new Windows Vista Learn more!  [quote][b]

planecrazydld(at)yahoo.co
Guest

Posted: Tue Aug 21, 2007 2:07 am Post subject: weight & balance with one scale?

just curious: aren't the scales required to be certified for W&B use anymore?



Phil Maxson <pmaxpmax(at)HOTMAIL.COM> wrote:[quote]    .hmmessage P { margin:0px; padding:0px } body.hmmessage { FONT-SIZE: 10pt; FONT-FAMILY:Tahoma }  That's how I did mine.

  

 Do Not Archive



Phil Maxson

 601XL/Corvair

 Northwest New Jersey

 [quote]  From: n4546v(at)mindspring.com

Subject: weight & balance with one scale?

Date: Mon, 20 Aug 2007 14:37:27 -0700



     This is probably a Rookie question and is only for discussion as I have access to three scales, but if one wanted, could you correctly weigh an airplane with just one scale if you put  [quote][b]

graeme(at)coletoolcentre.
Guest

Posted: Tue Aug 21, 2007 4:37 am Post subject: weight & balance with one scale?

Question

  

 I have a Ch701 a friend of mine is building a ch601  HD which has been un touched for a number of years .

 He hopes to soon be building again.

 I mentioned the solid alloy gear legs  .

 Can he build his fuse to take the alloy legs ( the  fuselage is not started )

 he intends to build a tail dragger and has the wing  mount wheel kit.

  

 Thanks Graeme 

 [quote]   ---

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Tue Aug 21, 2007 6:05 am Post subject: Re: weight & balance with one scale?

Not in Experimental land.

 	  planecrazydld(at)yahoo.co wrote: 	
		  just curious: aren't the scales required to be certified for W&B use anymore?

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

MaxNr(at)aol.com
Guest

Posted: Tue Aug 21, 2007 10:48 am Post subject: weight & balance with one scale?

I'm sure that a single scale (or two to average out) would be adequate. Sure, it takes a little longer. But how often are you going to do it? I would like to know if a 300 pound scale would be enough? What are the empty weights that builders are seeing on the MLG? The nose wheel? The price of scales go up for a 400 pound scale. Those analog spring scales may be inaccurate near their upper limits. I am going digital for the accuracy. I will try to borrow or rent because I'm cheap. Medical scales go up to 800 pounds. Alternatively: I weighed the tongue weight of my RV trailer using the mfg.'s published method. Bridge a solid fixed point and the scale with a 2 by 6 plank. Put the tongue on the plank at a 2/3 point. I doubled the reading and I found that the tongue weighed MORE OR LESS 700 pounds. I used a 300 pound bathroom scale. That's a whole lot of trouble for three wheels though.

 

 Bob from Pace,FL  601XL/Lyc

*************************.com/memed/aolcom30tour  [quote][b]

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue Aug 21, 2007 11:57 am Post subject: weight & balance with one scale?

Not for a homebuilt, any scale will do as long as you can get a fairly 

accurate reading from it. My DAR never asked me how I weighed my plane, 

just checked to make sure had a W&B sheet with my paperwork.



 	  Quote: 	
		   just curious: aren't the scales required to be certified for W&B use 

 anymore?

 

 */Phil Maxson <pmaxpmax(at)HOTMAIL.COM>/* wrote:


	


-- 

Bryan Martin

Zenith 601XL N61BM

Ram Subaru, Stratus redrive

Do Not Archive

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue Aug 21, 2007 12:09 pm Post subject: weight & balance with one scale?

I would use two 300 lb scales in tandem. That way you can keep the 

readings near midscale where it's more accurate and you don't have to 

worry about overloading the scales. Just put a plank between the two 

scales with the tire on the plank and add the two readings. Calibrate 

them first with known weights.



MaxNr(at)aol.com wrote:

 	  Quote: 	
		   I'm sure that a single scale (or two to average out) would be adequate. 

 Sure, it takes a little longer. But how often are you going to do it? I 

 would like to know if a 300 pound scale would be enough? What are the 

 empty weights that builders are seeing on the MLG? The nose wheel? The 

-- 
	


Bryan Martin

Zenith 601XL N61BM

Ram Subaru, Stratus redrive

Do Not Archive

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

planecrazydld(at)yahoo.co
Guest

Posted: Tue Aug 21, 2007 1:14 pm Post subject: weight & balance with one scale?

Wow! I just can't believe how this activity has morphed in the last 30 years since I was last seriously engaged in it!

   

  Did the DAR at the very least check the W&B sheet entries and math? Did he check the manufacturers/designers limits?

   

  Wow!



Bryan Martin <bryanmmartin(at)comcast.net> wrote:

  [quote]--> Zenith-List message posted by: Bryan Martin 



Not for a homebuilt, any scale will do as long as you can get a fairly 

accurate reading from it. My DAR never asked me how I weighed my plane, 

just checked to make sure had a W&B sheet with my paperwork.



 	  Quote: 	
		   just curious: aren't the scales required to be certified for W&B use 

 anymore?

 

 */Phil Maxson /* wrote:


	


-- 

Bryan [quote][b]

larry(at)macsmachine.com
Guest

Posted: Tue Aug 21, 2007 1:47 pm Post subject: weight & balance with one scale?

Bryan,

My weight empty with oil and coolant is 265, 264 mains and 231 for the nose.

I found my 300 lb scales are accurate +/-1 lb so long as you place a 1/4 

inch aluminum plate under each tire for weight distribution.

Larry McFarland 601HDS at www.macsmachine.com

Bryan Martin wrote:

 	  Quote: 	

 <bryanmmartin(at)comcast.net>

 I would use two 300 lb scales in tandem. That way you can keep the 

 readings near midscale where it's more accurate and you don't have to 

 worry about overloading the scales. Just put a plank between the two 

 scales with the tire on the plank and add the two readings. Calibrate 

 them first with known weights.

 MaxNr(at)aol.com wrote:

> I'm sure that a single scale (or two to average out) would be 

> adequate. Sure, it takes a little longer. But how often are you going 

> to do it? I would like to know if a 300 pound scale would be enough? 

> What are the empty weights that builders are seeing on the MLG? The 

> nose wheel? The

t_fogelson(at)yahoo.com
Guest

Posted: Tue Aug 21, 2007 2:59 pm Post subject: weight & balance with one scale?

I seem to remember when studying for the A&P test that

the plate should be greased so as the weight was

placed on the scale that it would slide and relieve

any sideways stress.  That was a long time ago and in

a galazy far far away.



Terry



--- LarryMcFarland <larry(at)macsmachine.com> wrote:



 	  Quote: 	
		   

 <larry(at)macsmachine.com>

 

 Bryan,

 My weight empty with oil and coolant is 265, 264

 mains and 231 for the nose.

 I found my 300 lb scales are accurate +/-1 lb so

 long as you place a 1/4 

 inch aluminum plate under each tire for weight

 distribution.

 

 Larry McFarland 601HDS at www.macsmachine.com

 

 Bryan Martin wrote:

 > 

 > <bryanmmartin(at)comcast.net>

 >

 > I would use two 300 lb scales in tandem. That way

 you can keep the 

 > readings near midscale where it's more accurate

 and you don't have to 

 > worry about overloading the scales. Just put a

 plank between the two 

 > scales with the tire on the plank and add the two

 readings. Calibrate 

 > them first with known weights.

 >

 > MaxNr(at)aol.com wrote:

 >> I'm sure that a single scale (or two to average

 out) would be 

 >> adequate. Sure, it takes a little longer. But how

 often are you going 

 >> to do it? I would like to know if a 300 pound

 scale would be enough? 

 >> What are the empty weights that builders are

 seeing on the MLG? The 

 >> nose wheel? The 

 

 

 

 



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MaxNr(at)aol.com
Guest

Posted: Tue Aug 21, 2007 4:49 pm Post subject: weight & balance with one scale?

Am I the only one to catch my math error on my "alternative method?" Double it if the weight is center plank. Seriously, its a clunky way to do the deed, but its still my fall back method. I will be looking for at least a 330 lb digital scale. My ball park figures for a plane not yet completed are based on some numbers from completed Lyc 601XL's. And that is north of 800 lbs empty weight. I hope I'm pleasantly surprised. I'm just guessing that the weight on the mains would be at least 650. Another thing. Not to offend, but I'm converting MM's to inches and do the chart C in Yankee inch/pound moments. I've been doing W/B in that format for half a century and I'm too old and ornery to change. I can build in metric but flying is another thing. When I was working for the man, I had been handed many manifests in kilos and even Stones. No problem. Furthermore, I've given some thought to moving the datum to the prop hub so that I don't have to compute with negative numbers. It does say "experimental" on the airplane after all. This will conform with most every thing I've flown in the past 40 years. Except for my 46 Luscombe and anything else certified before there was an FAA.  

 

 Do not archive

 Bob from Pace,FL    XL/Lyc

****************cover.aol.com/memed/aolcom30tour  [quote][b]

grs-pms(at)comcast.net
Guest

Posted: Tue Aug 21, 2007 5:51 pm Post subject: weight & balance with one scale?

Bob:

  

 There is nothing experimental about moving the  datum to any convenient point.  At Boeing, as  I remember, the zero datum is commonly placed ahead of the  nose. so there can be no negative moments.  (Well, I admit to a few  negative moments while I was at Boeing, but that's another matter.)  It was  also common to use a "constant moment" diagram to simplify weight and balance  calculations.  Have you used that sort of W/B presentation?

  

 George

  

 do not archive

 [quote]   ---

rsteele(at)rjsit.com
Guest

Posted: Tue Aug 21, 2007 6:32 pm Post subject: weight & balance with one scale?

To each his own. I just can't imagine going back to feet and inches.  I do woodworking and worked as a surveyor in my younger days so I've even worked with decimals of feet - yuck.  I've been looking for metric tools so when I go back to woodworking, after the plane, I don't have to revert to the 17th century.   Metric tools are just not available locally, I guess I might have to order them from Canada.



If you are talking about using a digital "bathroom scale" be aware that it may be less accurate than an analog one.  They still use a spring balance, but they have to include a digitizer too.  I'd stick with a high quality dial scale.   The Taylor Professional, which I have upstairs, goes up to 330 pounds.  I think I picked it up at Sam's Club a few years ago for about $35.   Someone suggested calibrating the scale  with known weights, which is the best thing to do. Maybe a few sacks of cement?  90lbs each if I remember right.  If you calibrate, the actually reading isn't as important as consistency.  If the readings are consistent, you can factor out the errors.



BTW, calculating wights and balance for the scale is exactly the same as it is for the plane.  You can reasonable use a lighter scale and place a board between the scale and a support.   The same math you use to figure W/B is used "in reverse" to get the true weight of the wheel.  The support needs to be the same height as the scale, and should be  a "knife edge" or round so that it can roll.  The goal to make sure the support allows the board to pivot freely.  Be VERY careful with such a setup.  Don't want to drop a plane.



Keep us posted on what you end up doing, and how it works.



Ron

On Aug 21, 2007, at 8:49 PM, MaxNr(at)aol.com (MaxNr(at)aol.com) wrote:

[quote]Am I the only one to catch my math error on my "alternative method?" Double it if the weight is center plank. Seriously, its a clunky way to do the deed, but its still my fall back method. I will be looking for at least a 330 lb digital scale. My ball park figures for a plane not yet completed are based on some numbers from completed Lyc 601XL's. And that is north of 800 lbs empty weight. I hope I'm pleasantly surprised. I'm just guessing that the weight on the mains would be at least 650. Another thing. Not to offend, but I'm converting MM's to inches and do the chart C in Yankee inch/pound moments. I've been doing W/B in that format for half a century and I'm too old and ornery to change. I can build in metric but flying is another thing. When I was working for the man, I had been handed many manifests in kilos and even Stones. No problem. Furthermore, I've given some thought to moving the datum to the prop hub so that I don't have to compute with negative numbers. It does say "experimental" on the airplane after all. This will conform with most every thing I've flown in the past 40 years. Except for my 46 Luscombe and anything else certified before there was an FAA.  

 

 Do not archive

 Bob from Pace,FL    XL/Lyc

****************cover.aol.com/memed/aolcom30tour  	  Quote: 	
		  

href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronics.com/Navigator?Zenith-List

href="http://forums.matronics.com">http://forums.matronics.com



	
[b]

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue Aug 21, 2007 7:21 pm Post subject: weight & balance with one scale?

His main concern was to make sure the paperwork was correct and 

everything was properly labeled and placarded. He did look over the 

plane and suggest some minor issues that needed correcting. I don't know 

how carefully he checked the math, the W&B sheet I used was published by 

Zenith with the limits printed on it. All I did was fill in the blanks 

and calculate the moments and CG.

David Downey wrote:

 	  Quote: 	
		   Wow! I just can't believe how this activity has morphed in the last 30 

 years since I was last seriously engaged in it!

 Did the DAR at the very least check the W&B sheet entries and math? Did 

 he check the manufacturers/designers limits?

 Wow!

 */Bryan Martin <bryanmmartin(at)comcast.net>/* wrote:

     Not for a homebuilt, any scale will do as long as you can get a fairly

     accurate reading from it. My DAR never asked me how I weighed my plane,

     just checked to make sure had a W&B sheet with my paperwork.

      > just curious: aren't the scales required to be certified for W&B use

      > anymore?

      >

      > */Phil Maxson /* wrote:

-- 

Bryan Martin

Zenith 601XL N61BM

Ram Subaru, Stratus redrive

Do Not Archive

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue Aug 21, 2007 7:29 pm Post subject: weight & balance with one scale?

My nosewheel load was a little over 300 lbs and it was just easier to 

put three 50 lb sandbags on the scales to verify accuracy than to mess 

with five or six.



LarryMcFarland wrote:

 	  Quote: 	
		   

 

 Bryan,

 My weight empty with oil and coolant is 265, 264 mains and 231 for the 

 nose.

 I found my 300 lb scales are accurate +/-1 lb so long as you place a 1/4 

 inch aluminum plate under each tire for weight distribution.

 

 Larry McFarland 601HDS at www.macsmachine.com

 

 Bryan Martin wrote:

> 

> <bryanmmartin(at)comcast.net>

>

> I would use two 300 lb scales in tandem. That way you can keep the 

> readings near midscale where it's more accurate and you don't have to 

> worry about overloading the scales. Just put a plank between the two 

> scales with the tire on the plank and add the two readings. Calibrate 

> them first with known weights.


	




-- 

Bryan Martin

Zenith 601XL N61BM

Ram Subaru, Stratus redrive

Do Not Archive

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

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