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Post Mod Weight and Balance

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Dave J

Joined: 19 Aug 2010
Posts: 2

Posted: Thu Aug 19, 2010 8:56 am Post subject: Post Mod Weight and Balance

Is anyone with a 601 and Jab getting weights similar to mine as follows:



Nose      204

Rt main  275

Lft main 278



Tot        757



If so, any thoughts of adding nose ballast?



(DO not know prior mod weights)



Dave J

DaveG601XL

Joined: 27 Oct 2006
Posts: 351
Location: Cincinnati, Oh

Posted: Thu Aug 19, 2010 1:43 pm Post subject: Re: Post Mod Weight and Balance

Dave,



What flight scenarios cause you to want to add nose ballast?  In my mind, there needs to be a specific reason to want to add dead weight to an airplane.  My airplane is quite close to yours, but with about 10-12 pounds more per main wheel (601XL with Jabiru).  Only at the most extreme case, which I have never needed to fly at yet, do I see me going out the rear end of the W&B envelope.  That is two decent sized people and a lot of baggage in the back.  I will more easily go over weight than I will go out the rear envelope.  Thus, for me, adding nose ballast hurts more than it helps.



So where do you see yourself realistically wanting to load your airplane?



Congrats on completing the mods, by the way,

_________________
David Gallagher
Cincinnati, OH area

jeffrey_davidson(at)earth
Guest

Posted: Thu Aug 19, 2010 3:31 pm Post subject: Post Mod Weight and Balance

Dave,

My 601 HD with the 3300A came in at 700 empty, 235 right, 235 left, 230

nose.  I'm about 13 hours into Phase I concentrating on CHTs and the air

plenums, but I have had no problems at all with me (190 lb) and full fuel

(30x6=180 lbs) in two leading edge tanks. 700+190+180=1070 plus about 30 lb

misc gear. So I have flown it at about 1100 lbs or so at this point with no

problems or bad characteristics.  

Jeff

--

Dave J

Joined: 19 Aug 2010
Posts: 2

Posted: Fri Aug 20, 2010 7:06 am Post subject: Re: Post Mod Weight and Balance

Thanks to all for your comments.



Let me add to my original post.



I would like to be able to invite an average male for a two hour flight in my 601xl.  10 pds of whatever in the baggage compartment.



I am 165 pds

average male 185

baggage 10



2 12 gal tanks



my weights and measurements are:



Rt main  275 pds , arm 668

lft main  278 pds,  arm 673

Nose      204 pds   arm -488



I have been crunching the numbers with Gary Ray's EXCEL spreadsheet at http://www.ch601.org/builder%20resources.htm



Dave

jeyoung65(at)aol.com
Guest

Posted: Fri Aug 20, 2010 7:26 am Post subject: Post Mod Weight and Balance

How did you come up with right main gear arm of  668 and 673 for the left main gear?  Are the main gears located at at differance distance from the wing's leading edge?   Jerry of Ga. 

 

   

 

 

   --

DaveG601XL

Joined: 27 Oct 2006
Posts: 351
Location: Cincinnati, Oh

Posted: Fri Aug 20, 2010 8:17 am Post subject: Re: Post Mod Weight and Balance

Dave,



I compared both your main and nose gear measurements to mine and they are all 45mm (1.8") or so more aft than what I measured on my 601XL.  Per my W&B sheet from ZAC, the datum is defined as a "plumb line from wing leading edge at Nose Rib #4."  Are you absolutely sure of your measurements?  



I agree that the numbers you have posted show a serious aft CG problem, but I am wondering about the gear location dimensions.  Please re-check using plumb bob with the top longeron level, tires inflated, hanger doors closed and on a flat surface.  Have someone else do an independent measurement and see if both your numbers agree.



Good luck,

_________________
David Gallagher
Cincinnati, OH area

Z601c(at)anemicaardvark.c
Guest

Posted: Fri Aug 20, 2010 11:20 am Post subject: Post Mod Weight and Balance

I can't speak for Dave, but differences such as these are not uncommon, even 

for certificated aircraft. 



This is a difference of .7%. This kind of a difference can be due to minor 

inaccuracies in the scales used. It can be due to minor human errors in 

measurement.



Two sides of a plane rarely weigh the exact same amount. One side of the plane 

may actually be 5 pounds heavier than the other side.



In my aircraft, the left side has the landing lights and pilot static system 

in it. I suspect, when I finish, I'll see it slightly heavier than the other 

side.

On Friday 20 August 2010 10:24:36 you wrote:

 	  Quote: 	
		   How did you come up with right main gear arm of  668 and 673 for the left

 main gear?  Are the main gears located at at differance distance from the

 wing's leading edge?   Jerry of Ga.


	


========================================

                                       Jim B. Belcher

                              BS,MS Physics, Math, Computer Science

                                            A&P/IA

                             General Radio Telephone Certificate

                                   Instrument Rated Pilot

                           Retired Aerospace Technical Manager

                        

========================================

Z601c(at)anemicaardvark.c
Guest

Posted: Fri Aug 20, 2010 11:57 am Post subject: Post Mod Weight and Balance

Woops! My bad ...I see you said moment arm, not weight. Sorry about that!



On Friday 20 August 2010 14:18:44 you wrote:

 	  Quote: 	
		   

 

 I can't speak for Dave, but differences such as these are not uncommon,

 even for certificated aircraft.

 

 This is a difference of .7%. This kind of a difference can be due to minor

 inaccuracies in the scales used. It can be due to minor human errors in

 measurement.

 

 Two sides of a plane rarely weigh the exact same amount. One side of the

 plane may actually be 5 pounds heavier than the other side.

 

 In my aircraft, the left side has the landing lights and pilot static

 system in it. I suspect, when I finish, I'll see it slightly heavier than

 the other side.

 

 On Friday 20 August 2010 10:24:36 you wrote:

 > How did you come up with right main gear arm of  668 and 673 for the left

 > main gear?  Are the main gears located at at differance distance from the

 > wing's leading edge?   Jerry of Ga.

 

 ========================================

                                        Jim B. Belcher

                               BS,MS Physics, Math, Computer Science

                                             A&P/IA

                              General Radio Telephone Certificate

                                    Instrument Rated Pilot

                            Retired Aerospace Technical Manager

 

 ========================================

 


	


-- 

========================================

                                       Jim B. Belcher

                              BS,MS Physics, Math, Computer Science

                                            A&P/IA

                             General Radio Telephone Certificate

                                   Instrument Rated Pilot

                           Retired Aerospace Technical Manager

                        

========================================

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Fri Aug 20, 2010 12:43 pm Post subject: Post Mod Weight and Balance

If your measurements are correct, you do have a problem. With that load, you'll hit the aft limit after burning off just six gallons of fuel. Where is your battery located? Is there any installed equipment you can move forward/



On Aug 20, 2010, at 11:06 AM, Dave J wrote:



 	  Quote: 	
		   

 

 Thanks to all for your comments.

 

 Let me add to my original post.

 

 I would like to be able to invite an average male for a two hour flight in my 601xl.  10 pds of whatever in the baggage compartment.

 

 I am 165 pds

 average male 185

 baggage 10

 

 2 12 gal tanks

 

 my weights and measurements are:

 

 Rt main  275 pds , arm 668

 lft main  278 pds,  arm 673

 Nose      204 pds   arm -488

 

 I have been crunching the numbers with Gary Ray's EXCEL spreadsheet at http://www.ch601.org/builder%20resources.htm

 

 Dave


	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus re-drive.

do not archive.

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

flyadive(at)gmail.com
Guest

Posted: Fri Aug 20, 2010 1:03 pm Post subject: Post Mod Weight and Balance

Jerry & Gaggle:

I gather these numbers are in mm... And I think in inches.

So this works out to just about 3/16".. THAT IS NOTHING!  Very easy to be off that much and I think the guy did a GREAT job of measuring.

 As stated before it is VERY easy to be off in wheel weight.  I worked on a RV6 that had 50 pounds difference between wheels.  Why? Not sure but there was an auto pilot with a huge servo motor.

 Barry

On Fri, Aug 20, 2010 at 3:18 PM, Jim Belcher <Z601c(at)anemicaardvark.com (Z601c(at)anemicaardvark.com)> wrote:

[quote] --> Zenith-List message posted by: Jim Belcher <Z601c(at)anemicaardvark.com (Z601c(at)anemicaardvark.com)>

 I can't speak for Dave, but differences such as these are not uncommon, even

 for certificated aircraft.

 This is a difference of .7%. This kind of a difference can be due to minor

 inaccuracies in the scales used. It can be due to minor human errors in

 measurement.

 Two sides of a plane rarely weigh the exact same amount. One side of the plane

 may actually be 5 pounds heavier than the other side.

 In my aircraft, the left side has the landing lights and pilot static system

 in it. I suspect, when I finish, I'll see it slightly heavier than the other

 side.

 On Friday 20 August 2010 10:24:36 you wrote:

 > How did you come up with right main gear arm of  668 and 673 for the left

 > main gear?  Are the main gears located at at differance distance from the

 > wing's leading edge?   Jerry of Ga.

 ===============

                                        Jim B. Belcher

                               BS,MS Physics, Math, Computer Science

                                             A&P/IA

                              General Radio Telephone Certificate

                                    Instrument Rated Pilot

                            Retired Aerospace Technical Manager

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