Matronics Email Lists :: View topic - Weight and Balance question

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Weight and Balance question

Matronics Email Lists Forum Index -> Europa-List

View previous topic :: View next topic

Author Message

jeffwill55(at)sbcglobal.n
Guest

Posted: Sun Apr 04, 2021 7:37 am Post subject: Weight and Balance question

I am working on an initial weight and balance for my Europa XS and I was wondering how the baggage arm listed in the Europa manual came about. 

Does anyone know, and is it worth thinking about?

Page 6-4 of The "XS Trigear Owners Manualâ€, Issue 7, January 2015, shows the arm for baggage at 88. The weight and balance arm measurements are taken starting at the rear of the joggle for the cowling, which is at Fuselage Station FS 29.25. 



As I measure it, the bottom of the D-panel bulkhead at the back of the baggage area is at 94.5â€ aft of the joggle, which is FS 103.75. A typical carry-on bag is 23 inches tall, and I expect the CG for that in the aircraft would be about at the mid-point, or 11.5 inches forward of the base of the D panel bulkhead. 



The result of 103.75 - 11.50 is an arm of 92.25, not 88.



Six and a half (6.5) inches in the baggage arm does make a difference with full bags loaded onboard. And CG calculations do need to be based on what I are putting on board and where those things are actually located. 



However, I expect using 88 is close enough - unless it looks like I am getting close to the limits, which I would think should be seldom, if ever. 



Right?



Regards,



Jeff Williams

Remi Guerner

Joined: 14 Dec 2010
Posts: 284

Posted: Sun Apr 04, 2021 11:21 pm Post subject: Re: Weight and Balance question

Jeff,

That is a good point. I have always used 94" for the bagage, as I do think the 88" figure is wrong for the XS bagage bay. 

Remi

F-PGKL

Peter jeffers

Joined: 24 Aug 2020
Posts: 20
Location: hp143hr

Posted: Mon Apr 05, 2021 1:17 am Post subject: Weight and Balance question

Hi Jeffrey,

 

Whatever the rights and wrongs of your emailÂ  may be, the 88 ins WAS the correct figure for the original classic mono prior to the baggage bay extension mod (I have forgotten the no of this mod). Your figure of 92.25" may be more correct but 88" remains in the book.

 

Pete JÂ  ( LAA inspector rep to the Europa Club)

 

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Jeffrey Williams

Sent: 04 April 2021 16:37

To: Europa-List Digest Server

Subject: Weight and Balance question 

 

I am working on an initial weight and balance for my Europa XS and I was wondering how the baggage arm listed in the Europa manual came about. 

 



Does anyone know, and is it worth thinking about?

 



Page 6-4 of The "XS Trigear Owners Manualâ€, Issue 7, January 2015, shows the arm for baggage at 88. The weight and balance arm measurements are taken starting at the rear of the joggle for the cowling, which is at Fuselage Station FS 29.25. 



 



As I measure it, the bottom of the D-panel bulkhead at the back of the baggage area is at 94.5â€ aft of the joggle, which is FS 103.75. A typical carry-on bag is 23 inches tall, and I expect the CG for that in the aircraft would be about at the mid-point, or 11.5 inches forward of the base of the D panel bulkhead. 



 



The result of 103.75 - 11.50 is an arm of 92.25, not 88.



 



Six and a half (6.5) inches in the baggage arm does make a difference with full bags loaded onboard. And CG calculations do need to be based on what I are putting on board and where those things are actually located. 



 



However, I expect using 88 is close enough - unless it looks like I am getting close to the limits, which I would think should be seldom, if ever. 



 



Right?



 



Regards,



 



Jeff Williams



 



 



 

 



Virus-free. www.avg.com

_________________
Pete

kingsnjan(at)westnet.com.
Guest

Posted: Mon Apr 05, 2021 2:51 am Post subject: Weight and Balance question

Hello Jeff,



FWIW, when I did the W&B on my Mono Classic I calculated the moment arms for both the forward and rear sections of the extended baggage bay. 

For the calculations, I used a 20.5 kg bag of wild bird seed as I considered this to be a good way to spread the load. 

In the forward section the bag was stood vertically. Calculated arm was 84.33â€

In the rear section, the bag was placed flat across the aircraft and pushed as far back as possible.  Calculated arm was 96.26â€

Best regards

Kingsley in Oz



Sent from my iPhone



 	  Quote: 	
		  On 5 Apr 2021, at 1:44 am, Jeffrey Williams <jeffwill55(at)sbcglobal.net> wrote:



ï»¿I am working on an initial weight and balance for my Europa XS and I was wondering how the baggage arm listed in the Europa manual came about. 

Does anyone know, and is it worth thinking about?

Page 6-4 of The "XS Trigear Owners Manualâ€, Issue 7, January 2015, shows the arm for baggage at 88. The weight and balance arm measurements are taken starting at the rear of the joggle for the cowling, which is at Fuselage Station FS 29.25. 



As I measure it, the bottom of the D-panel bulkhead at the back of the baggage area is at 94.5â€ aft of the joggle, which is FS 103.75. A typical carry-on bag is 23 inches tall, and I expect the CG for that in the aircraft would be about at the mid-point, or 11.5 inches forward of the base of the D panel bulkhead. 



The result of 103.75 - 11.50 is an arm of 92.25, not 88.



Six and a half (6.5) inches in the baggage arm does make a difference with full bags loaded onboard. And CG calculations do need to be based on what I are putting on board and where those things are actually located. 



However, I expect using 88 is close enough - unless it looks like I am getting close to the limits, which I would think should be seldom, if ever. 



Right?



Regards,



Jeff Williams

Duncan McFadyean

Joined: 18 Jan 2011
Posts: 220

Posted: Mon Apr 05, 2021 4:30 am Post subject: Weight and Balance question

Priceless information.   

Duncan Mcf.   

do not archive.    	  Quote: 	
		      On 05 April 2021 at 11:50 Kingsley Hurst <kingsnjan(at)westnet.com.au> wrote:     

     

Hello Jeff,         

    

         FWIW, when I did the W&B on my Mono Classic I calculated the moment arms for both the forward and rear sections of the extended baggage bay.     

         

    

         For the calculations, I used a 20.5 kg bag of wild bird seed as I considered this to be a good way to spread the load.     

         

    

         In the forward section the bag was stood vertically. Calculated arm was 84.33â€    

         In the rear section, the bag was placed flat across the aircraft and pushed as far back as possible.  Calculated arm was 96.26â€    

         

    

         Best regards    

         Kingsley in Oz      

      

           Sent from my iPhone     

           

       	  Quote: 	
		         On 5 Apr 2021, at 1:44 am, Jeffrey Williams <jeffwill55(at)sbcglobal.net> wrote:        

        

                   I am working on an initial weight and balance for my Europa XS and I was wondering how the baggage arm listed in the Europa manual came about.                       

               Does anyone know, and is it worth thinking about?                         

                 Page 6-4 of The "XS Trigear Owners Manualâ€, Issue 7, January 2015, shows the arm for baggage at 88. The weight and balance arm measurements are taken starting at the rear of the joggle for the cowling, which is at Fuselage Station FS 29.25.         

                         

                 As I measure it, the bottom of the D-panel bulkhead at the back of the baggage area is at 94.5â€ aft of the joggle, which is FS 103.75. A typical carry-on bag is 23 inches tall, and I expect the CG for that in the aircraft would be about at the mid-point, or 11.5 inches forward of the base of the D panel bulkhead.         

                         

                 The result of 103.75 - 11.50 is an arm of 92.25, not 88.        

                         

                 Six and a half (6.5) inches in the baggage arm does make a difference with full bags loaded onboard. And CG calculations do need to be based on what I are putting on board and where those things are actually located.         

                         

                 However, I expect using 88 is close enough - unless it looks like I am getting close to the limits, which I would think should be seldom, if ever.         

                         

                 Right?        

                         

                 Regards,        

                         

                 Jeff Williams

John Wighton

Joined: 18 May 2010
Posts: 241

Posted: Tue Apr 06, 2021 1:20 am Post subject: Re: Weight and Balance question

Gentlemen (and Ladies, if present),



All this discussion on CG moment arm made my weekend, an absolute hoot from start to finish (is it finished yet?).  This is not helped by the rather cack-handed approach prescribed in the POH.



A reasonably common piece of data in this thread is the location of the datum.  But even that may vary depending on who/how weighed/measured the aircraft - treat this as a variable across the fleet, but a constant for your aeroplane.  Any calculation of W&B needs to use the actual mass as measured and the actual moment arm as measured.  



Weigh the item (you, pax, the dog, grannies apple pie or your bag of birdseed).  Use that data in a spreadsheet.



Link: http://www.lightaircraftassociation.co.uk/engineering/Weight%20and%20balance/w_and_b_main.html



Skydemon also provides a very nice W&B calculator (it is legally necessary to do this for EVERY flight), which makes it easy-peazy.



The moment arm I use for baggage is a measurement to the centre of the bay.  However, the Europa Aircraft method of establishing the FS 0.0 datum is a comedy.  A position 29.25" fwd of the "Rear of joggle for cowling in fuselage moulding" needs to be marked.



This is totally unnecessary - the cowling to fuselage joint is as good a datum as any.  It  requires all moment arms forward of it to be given a negative sign (for the initial W&B calculation and any subsequent firewall forward mods) and all those aft of it to be positive.



Just measure along the horizontal fuselage datum WL (level sill can be used as per POH) to the FS of the item to be measured. 



Attached is an extract from the POH (note the depicted Trigear also has a secreted mainwheel protruding from the fuselage!).

Europa_W&B.jpg

Description:

Filesize:

237.7 KB

Viewed:

5412 Time(s)

_________________
John Wighton
Europa XS trigear G-IPOD

JohnFrance

Joined: 17 Sep 2014
Posts: 78
Location: Grenoble France

Posted: Wed Apr 07, 2021 1:18 am Post subject: Re: Weight and Balance question

John,

Weight and balance is an interesting subject and everyone has their opinion on whatâ€™s best.  

While a datum of 29,25 forward of the joggle might seem strange initially, it could have been 30â€ or any other number forward of the entire aircraft. This simplifies the calculation by only having to deal with positive number and thus reducing the likelihood of errors when calculating. 

The 2 examples I found in the LAA document you gave a link to showed a Cloudpusher aircraft with the datum 3191mm forward of the C of G which put it on the nose of the aircraft and a Sportster with the datum 70â€ in front of the leading edge, a small distance in front of the aircraft. 



I donâ€™t think Ivan or Andy were far off the mark, or maybe 0,75â€ for a whole number. ðŸ˜

_________________
Europa mono Nr 192

Dave Disney

Joined: 16 Aug 2010
Posts: 54
Location: Weston-Super-Mare

Posted: Wed Apr 07, 2021 1:43 am Post subject: Re: Weight and Balance question

As a matter of interest, has anyone recorded the station points for the various bulkheads in the Europa such as 'front of seats', 'seats rear vertical face', 'forward face of baggage bay', 'aft face of baggage well', etc?

kingsnjan(at)westnet.com.
Guest

Posted: Wed Apr 07, 2021 2:37 am Post subject: Weight and Balance question

ï»¿ 	  Quote: 	
		  On 7 Apr 2021, at 7:25 pm, JohnFrance <77alembert(at)gmail.com> wrote:



While a datum of 29,25 forward of the joggle might seem strange initially, it could have been 30â€ or any other number ......

	


Whilst it is true any position can be chosen, there is a very valid and logical reason why the reference point was chosen to be 29.25â€ forward of the joggle. 

The reference point FS 0.00 for the original Classic was the forward face of the engine cowl behind the spinner.  This position corresponds to 29.25â€ forward of the joggle on the Classic and the XS.   The front face of the cowl on the XS is further forward to accommodate the relocated engine position on the XS. 

Over and out

Kingsley in Oz.

Peter jeffers

Joined: 24 Aug 2020
Posts: 20
Location: hp143hr

Posted: Thu Apr 08, 2021 1:48 am Post subject: Weight and Balance question

Hi John,

Stupid you may call the position of the zero datum but the reason is mostly

historical, very practical and it standardises critical numbers like CG

positions across our fleet of Classics, XS's & motor gliders.

Taken in order the history started with the Classic where zero datum was the

front of the engine cowl. It was at this time also considered logical for

the sake of non mathematicians to keep all figures positive and not confuse

the issue with negative numbers. You don't have to look very far to find

stupid errors in critical calculations caused by deliberately introducing

negative moments. 

As the XS nose was extended slightly further forward it was sensible to

leave zero datum as was. Hence the 29 3/4" point on ALL marks of Europa is

where the front of the engine cowl would have been had it been a classic.

This means, and this is important, that the CG limits and fuel tank pilot

passenger and baggage load points for all marks are consistent. It all makes

for less risk of confusion and error. 

Had the first type of Europa to be produced been an XS then zero datum would

probably have been a quite different location.

Pete J

PS There may be good reason to change the baggage station of 88 ins to a

more realistic figure in light of the fact that this figure is still the

same as was applicable prior to the extended baggage bay mod.



--

_________________
Pete

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Thu Apr 08, 2021 7:15 am Post subject: Weight and Balance question

Well said Pete. 

It may be worth the research and time to do the aft CG flight tests to see if extension of the rear limit is possible.  Andy may be the best guy to go to.    

Story time: 

Years ago, after Sun 'n Fun, Andy and I flew, and we discussed for a moment the extended baggage bay and gear placement when loading.  Unfortunately, our discussion was abruptly ended by the Former President of Europa Aircraft, Keith Wilson, who said "We spun tested and inch past the CG so who cares, we need to go."   What a nice guy. 

  

When loading for my first long cross country with my Classic (XS cowl and FWF and Extended baggage that was home made but nearly exact  except for the size of the access holes) I loaded as follows:  

With two bags (20" airline roll around at 15 pounds each planned but really 20 pounds) 10 pounds of tools and oil in the trigear bracing,  flight bag at 10 pounds, kids toys, hair curlers and essentials, and full fuel (new fuel tank and filled to the neck), I computed the weight in the rear at right at 80 pounds (or so, as I only was figuring 50).   My gear legs are at 70  inches so all was fine until I pushed the tail down and the angle changed.  Thud, the plane hit on the tail tie down and stayed there with no one in the seats.  A recalculation of the "needed" baggage and its placement was made. 

  

The weight and balance was computed based on the short 88 inches from the POH which I knew was a stretch.  Bags were arranged hard at the tank as was the tool bag and oil tucked in the X bracing of the trigear wells.  Flight bag was held on top of the roll arounds under my baggage net.  Kids toys and hair care essentials went at the aft bulkhead and I computed the weight and arm to be 62.5.  It was the fuel that surprised me.   The new tank held a full 20 gallons to the top of my trigear neck not 18, why the difference I didn't measure but the fuel was carefully checked and found to be 76 inches on the average from full to empty.  A trigear sitting level can pack a few more cubic inches  in I guess.  A new recalculation of the weight and balance was made based on the fuel weight of the new tank and plumbing.  My scales were giving me trouble, and it took a couple of days.  Not much of a CG change, but still my assumptions were not accurate.  I needed to measure and weigh both airplane and bags and their placement then test. 

  

Of course, the Europa flew fine but the nose was just as I found in flight testing at the full aft CG limit, just a little lighter in  pitch on takeoff and damping in flight was still superb because of the  well designed tail. 

  

It would be prudent to measure back from the joggle and recompute when planning your load in any aircraft then recompute via the 29.25"  and do the calculations for full fuel and landing fuel.  The Cherokee Six is one that scares the heck out of me as does the Cessna 207 when I see guys loading them willy nilly with large passengers and heavy bags.   

  

Trust no one, verify, measure and weigh.  Don't arbitrarily build an intentionally nose heave A.P.S for load as landing and approach light weight with two full sized guys is a bit nose heavy in the flare.  Building tail heavy for two 250 pound pilots is not prudent either for flying solo with baggage.  Do the measurements and calculate.  It's just math. Then compute your CG for many loadings and test carefully.  I learned when converting a Zenith 601 for a very large individual (275 pounder) required me to actually weigh the aircraft with him in it and a second pilot with and without fuel (tank is at the firewall and in the wings) to get a handle on his loading restrictions.  That was my first eye opener on these small aircraft.  If you stepped on the Zeniths aft mounted step to get in the plane with him in it and full fuel, the plane fell on its butt and damaged the rudder.  What a lesson.  I was delighted with the compact arrangement of the Europa for CG control.  

  

Within the CG limits and especially from 59-62.5 inches I find the Europa delightful.  Make sure stab throws are near the max for assured control.  Follow prudent testing when near the limits of the CG.  I find full forward CG to require a slightly faster round out if the stab is only 12 degrees up travel, and I find it more comfortable to carry 5 more knots in my aircraft if at the full forward CG.  I moved the battery to the rear when I added the Airmaster and have never looked back.  APS is right at 59 for N12AY. 

  

I keep an electronic fish scale (good to 25 pounds) and a tape measure handy when carrying props and things in the Europa that are heavy/bulky.  Sometimes when solo, I strap heavy props and things in the seat next to me. 

In your computations for your POH include the various loading extremes of max forward/aft possible, two pilot, fully loaded for cross  country with full fuel and landing fuel.   It is just math.  I do mine on Excel for neatness and my Avare flight planning program now has the data for XC use.  The POH is in the aircraft with the actual fore and aft limitations on loading and my phone has EVERY manual loaded on the cloud and the data card for the airplane and its equipment. 

  

If you are building an airplane and watching TV at night, change your priorities and do the research on every component in your aircraft,  and for CG that means loading assumptions too.   YOU are the manufacturer and therefore responsible for the safety of your aircraft, documentation, flight restrictions and operational limitations.  Oh by the way, stay flight proficient and married at the same time.  Aircraft builders are busy people. 

  

Best Regards 

Bud Yerly 

  

  

  

--

wdaniell.longport(at)gmai
Guest

Posted: Thu Apr 08, 2021 7:54 am Post subject: Weight and Balance question

When I flew from Colombia to USA I strapped the aux tank to the trigear

cross bar snug up against the rear of the main tank.  The aux tank and

transfer pump weighs 16 lbs and holds 10 gals.  I made a sort of bath tub

to hold the turtle pac bladder precisely to concentrate the weight as far

forward as possible, even so from the center of the main tank to the center

of the aux tank is 11 inches suggesting the arm of the POH 88 is about

right.     Another 10 lbs of tools went under the seats and we had 10lbs of

ipads handheld radio batteries and liferaft..  We had 5lbs each of T shirts

and underwear which went behind the aux tank in the baggage bay.



Lbs arm moment

Front 177.00 15.00 2,655.00

Right 385.00 70.80 27,258.00

Left 385.00 70.80 27,258.00

APS 947.00 60.37 57,171.00

tools Maps GPS headset etc 20.00 56.00 1,120.00

Pilot 200.00 56.00 11,200.00

Pax 200.00 56.00 11,200.00

Baggage 10.00 88.00 880.00

Aux fuel tank weight 16.28 88.00 16.28

Subtotal 1,393.28 58.56 81,587.28

fuel 108.00 76.00 8,208.00

Aux fuel 60.00 88.00 5,280.00

1,561.28 60.90 95,075.28

MTOW 1450

Available -111.28



William Daniell

LONGPORT

+1 786 878 0246

On Thu, Apr 8, 2021 at 8:19 AM Bud Yerly <budyerly(at)msn.com> wrote:



[quote] Well said Pete.



 It may be worth the research and time to do the aft CG flight tests to see

 if extension of the rear limit is possible.  Andy may be the best guy to

 go to.



 *Story time:*



 Years ago, after Sun 'n Fun, Andy and I flew, and we discussed for a

 moment the extended baggage bay and gear placement when loading.  Unfortunately,

 our discussion was abruptly ended by the Former President of Europa

 Aircraft, Keith Wilson, who said "We spun tested and inch past the CG so

 who cares, we need to go."   What a nice guy.



 When loading for my first long cross country with my Classic (XS cowl and

 FWF and Extended baggage that was home made but nearly exact except for the

 size of the access holes) I loaded as follows:



 With two bags (20" airline roll around at 15 pounds each planned but

 really 20 pounds) 10 pounds of tools and oil in the trigear bracing, flight

 bag at 10 pounds, kids toys, hair curlers and essentials, and full fuel

 (new fuel tank and filled to the neck), I computed the weight in the rear

 at right at 80 pounds (or so, as I only was figuring 50).   My gear legs

 are at 70 inches so all was fine until I pushed the tail down and the

 angle changed.  Thud, the plane hit on the tail tie down and stayed there

 with no one in the seats.  A recalculation of the "needed" baggage and

 its placement was made.



 The weight and balance was computed based on the short 88 inches from the

 POH which I knew was a stretch.  Bags were arranged hard at the tank as

 was the tool bag and oil tucked in the X bracing of the trigear wells.  Flight

 bag was held on top of the roll arounds under my baggage net.  Kids toys

 and hair care essentials went at the aft bulkhead and I computed the weight

 and arm to be 62.5.  It was the fuel that surprised me.  The new tank

 held a full 20 gallons to the top of my trigear neck not 18, why the

 difference I didn't measure but the fuel was carefully checked and found to

 be 76 inches on the average from full to empty.  A trigear sitting level

 can pack a few more cubic inches in I guess.  A new recalculation of the

 weight and balance was made based on the fuel weight of the new tank and

 plumbing.  My scales were giving me trouble, and it took a couple of days

John Wighton

Joined: 18 May 2010
Posts: 241

Posted: Fri Apr 09, 2021 1:08 am Post subject: Re: Weight and Balance question

Response to Pete and others.



Clearly the existing system is faultless - that is why so many people are confused and key moment arms are simply wrong.  Including, most likely, the baggage bay moment arm published for 20+ years in the POH!



Say no more.

_________________
John Wighton
Europa XS trigear G-IPOD

Display posts from previous:

	Matronics Email Lists Forum Index -> Europa-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum