W&B question

[Wingover]

Hi All,

New to me M20J 1987 (205 model) that was "converted to the 2900 Lbs (1315 KG here in Europe).  It seems that the CG calculation puts the CG very far back and I am wondering if others have the same issue.  When I load weights for 4 people 55+75 KG in front and 60+80 KG in the back plus one 10KG baggage I am out of balance on the very rear part of the envelop.

Is this normal?  you can't really fly with 4 skinny/normal weight adults?  Here is the CG envelop I have (metric)

Thanks !

 

[A64Pilot]

I don’t know what I’m looking at with that chart, but my 81J it’s nearly impossible to load out of CG, it’s one of the very attractive things to me about a Mooney.

I think if you can easily get out of aft CG that there is likely a math error somewhere

[PT20J]

Your empty weight seems about right.

i assume the CG shown is empty CG in millimeters. If so, it seems way too far aft. Mine is 1168 for a 2900 lb. M20J.

This can happen if the CG calculations are not done correctly. If you have a record of the weights for each wheel when it was weighed, I would recalculate the CG using the exact procedure in the POH.

[Wingover]

14 minutes ago, PT20J said:

Your empty weight seems about right.

i assume the CG shown is empty CG in millimeters. If so, it seems way too far aft. Mine is 1168 for a 2900 lb. M20J.

This can happen if the CG calculations are not done correctly. If you have a record of the weights for each wheel when it was weighed, I would recalculate the CG using the exact procedure in the POH.

Thank you!  Here is what I got for weights:

 

[Wingover]

And this is the POH with millimeters on top and inches below.

[Wingover]

Yes, I agree.  Going through the POH to try and figure it out

[Ragsf15e]

2 hours ago, Wingover said:

Hi All,

New to me M20J 1987 (205 model) that was "converted to the 2900 Lbs (1315 KG here in Europe).  It seems that the CG calculation puts the CG very far back and I am wondering if others have the same issue.  When I load weights for 4 people 55+75 KG in front and 60+80 KG in the back plus one 10KG baggage I am out of balance on the very rear part of the envelop.

Is this normal?  you can't really fly with 4 skinny/normal weight adults?  Here is the CG envelop I have (metric)

Thanks !

 

I have an older (F) model but it’s got similar weight and balance characteristics as the J.  I did a sample load with 4 adults at 79kg each and 34kg in baggage and 30gallons of fuel.  Still in the middle of the envelope (although maxing out my useful load).

You will find that lots of shops make an error on measuring your cg/arm.  I promise these airplanes are hard to load to an aft cg.

[ArtVandelay]

I went through every W&B sheet I had (missing 1) and put it all into a spreadsheet, found about 1 error for every 5 entries, in my case they balanced out. I recommend you do the same.

[Wingover]

18 minutes ago, ArtVandelay said:

I went through every W&B sheet I had (missing 1) and put it all into a spreadsheet, found about 1 error for every 5 entries, in my case they balanced out. I recommend you do the same.

Yes, It looks like I have to.  I am not near the plane for a few days.  Anyone has the measurements Lm/r and Lm/n as attached?  Just to see how close those are to mine..

[Wingover]

1 minute ago, 1980Mooney said:

It varies by plane even within a specific model. These are hand built planes. That is what your A&P was supposed to do. If someone gives you numbers it will just be an estimate. 
 

Do you know if your plane was reweighed on load cells when they did the 2,900 lb MGW increase?  Or was it just a paper entry?  If a paper entry go back to the earlier version when it was 2,740 lbs. You should still have that. Look at the earlier arm or CG when empty. 
 

If it was reweighed then the A&P totally screwed up. Probably need a reweigh. 

It was reweighed.  I understand that the measurements will be different but was hoping to see how off mine are. 

[PeteMc]

4 hours ago, PT20J said:

This can happen if the CG calculations are not done correctly.

I just had my W&B redone with the new interior.  With the first one I got back, I couldn't be in the plane alone without being way forward out of CG unless there was 100+ pounds in the Baggage area.  They messed up the front wheel measurement by a LOT and that messed everything up.  Eventually they got it straightened out and the Empty Weight only went up 25lbs with the new interior. 

My takeaway is to always look at an old W&B if there is any question.  ALL of the numbers should be close and if you see one that is a BIG change, it may be the error.

 

Edited February 9 by PeteMc

[Wingover]

Thank you for posting this.  It makes a lot of sense now.