Battery location

[Alyair]

I have a 66 M20E. After my last upgrades we did a weight and balance. I was surprised with the outcome. We removed 35lb of gauges,wire, and instruments. We also installed a plane power alternator conversion. The aircraft already had a new style starter. We installed an EI.MVP50 a Garmin aera560. We removed the 2nd vor radio,ADF, loran and DME.  When she was new she waighed in at 1633 with cg of 45.7 empty.  Now with all this light weight new gear she weighs in at 1671.4 with cg of 48.02. She was painted once in the 80s has led a pamperd life of heated hangers from previous owner of 25 years. I can live with the new empty weight but I can see new limits on my useful load as I will go out the back of the envelope before reaching gross weight .  So here is my question.  Is it possible to relocate the battery from behind the rear seat to in front of the firewall? We're there Moonies built this way from the factory? I think I have removed so much weight up front and very little aft. Thanks in advance for all your input. I enjoy this forum very much.  

[takair]

Something doesn't sound right.  Have you run the numbers again?  I've seen simple errors cause big shifts and then carried forward for years.  The original aircraft and big power supplies in the back and even they didn't push out the back...

The C has the battery up there and it makes it a real PITA to do simple things like change your oil or check mags.

[C-GHIJ]

41 minutes ago, Alyair said:

I have a 66 M20E. After my last upgrades we did a weight and balance. I was surprised with the outcome. We removed 35lb of gauges,wire, and instruments. We also installed a plane power alternator conversion. The aircraft already had a new style starter. We installed an EI.MVP50 a Garmin aera560. We removed the 2nd vor radio,ADF, loran and DME.  When she was new she waighed in at 1633 with cg of 45.7 empty.  Now with all this light weight new gear she weighs in at 1671.4 with cg of 48.02. She was painted once in the 80s has led a pamperd life of heated hangers from previous owner of 25 years. I can live with the new empty weight but I can see new limits on my useful load as I will go out the back of the envelope before reaching gross weight .  So here is my question.  Is it possible to relocate the battery from behind the rear seat to in front of the firewall? We're there Moonies built this way from the factory? I think I have removed so much weight up front and very little aft. Thanks in advance for all your input. I enjoy this forum very much.  

You know back then (before 1975) that the factory did the weight and balance report WITHOUT oil in the engine.  8 quarts at about 6.5lbs per quart (that's 52 pounds) that won't be on the factory weight and balance report.

The early Moonies have the battery on the firewall (mine does).  Don't know if you can move yours there?

[DXB]

My '68C has the battery on the firewall- is the rear battery an E model thing, or did someone move the poster's battery previously?   Also is the new w/b calculated or based on direct reweighing?

[takair]

7 minutes ago, DXB said:

My '68C has the battery on the firewall- is the rear battery an E model thing, or did someone move the poster's battery previously?   Also is the new w/b calculated or based on direct reweighing?

It's an E thing and I think all models after that.  

[sleepingsquirrel]

32 minutes ago, C-GHIJ said:

You know back then (before 1975) that the factory did the weight and balance report WITHOUT oil in the engine.  8 quarts at about 6.5lbs per quart (that's 52 pounds) that won't be on the factory weight and balance report.

The early Moonies have the battery on the firewall (mine does).  Don't know if you can move yours there?

Oil goes at 15 lbs for 8 quarts. 7.5 lbs per gal

Edited February 19, 2016 by sleepingsquirrel

[C-GHIJ]

My bad, I meant gallon wrote quart.  Guess my old brain isn't as good as I think it is.

[Alyair]

This is copy of the weight and balance performed 4 months ago. The numbers I cited were from the original empty weight and cg computations. There were numerous mathematical computations throughout the life of the aircraft.

[Alyair]

I'm pretty sure the battery is in its original location. It all looks factory.

 

[takair]

Hmm.  You show nose wheel moment at .1 and main as 67.1.  My old E AFM shows -1.0 and 65.3 respectively. Using those numbers you would be at a more reasonable 46.48 as weighed. Did you get the arms from the book or were they measured?  The datum on mine is the nose gear support bolt in the wheel well.

[Alyair]

These are the numbers from my original AFM.. The numbers 67.0  and 67.1 are a mystery to me. Do they make sense? It seems to me that they should be switched

 

[takair]

Well, not necessarily. I'm just surprised how different they are from mine, but I think I understand.  Looks like Mooney took real time numbers for weight and balance, so this is where your axels actually SAT.  In thinking about it more, you would need to take some actual measurements, at the same weight you weighed the aircraft and with it level (but NOT using jacks).  These numbers depend on gear rigging, puck health and weight.  For now, you may want to run a manual update from the original wt and balance, as something seems off here.  Was the aircraft level when weighed?

[C-GHIJ]

The original from the factory was done WITHOUT the engine oil.  It was not subtracted from your new calculation.  Also the weighs recorded on the gears are not close to the factory ones.  If you look at the factory W+B you will see that all three gear have about the same weigh on them.  The new one has the nose gear over a 100 lbs lighter.  That alone tells me that the plane was not level when it was weighed.  The report is not accurate.  If they wanted to use the factory numbers, they could have weighed the original components that where removed and just done the math (it would have been more accurate)  I would not trust the report that was done.  It seems that the person doing it was just putting numbers into spreadsheet and didn't really understand how to do the math properly.

At this point, I recommend that you take the aircraft to someone that ACTUALLY knows how to preform a proper weight and balance (the old school way) and do a fresh W+B report on your aircraft.  You will need to de-fuel the plane to get a proper W+B done.  You can not JUST subtract the amount of fuel as you really have no way of knowing EXACTLY how much fuel is in the aircraft. (Fuel weighs different amounts per lbs at different temperatures) .  The aircraft MUST be leveled according to the manufactures instructions to get the proper readings.  It is surprising how much the readings can change if the aircraft is not level.

Get a proper W+B done on the aircraft, your safety and that of your passengers depends on it.  I don't want to read about another pilot on this site dying because of a preventable mistake. 

[Alyair]

I need to go back to the shop and ask some questions. I wasn't there for the actual w/b.

I should have gotten on this sooner. 

 

 

[carusoam]

Please don't change things because they 'seem' to make sense. The cost of being wrong is just too high.  The ability of getting it right is available from a mechanic with a scale or three...

the WnB reference is shown in the page that you have posted.  It is probably called a weight and balance record.  The dashed vertical line goes right through that magic point of the front landing gear.  All arms are measurements from there. That page is not in the POH of that time is it?  Looking through my C's POH I'm unable to find it...I recall a single page in it's maintenance logs.

With so many changes over the years, are the weights you are using from an actual recent weighing of the aircraft?

some planes use the fire wall as a reference.  The pivot point of the landing gear is a tad more specific.  Some fire walls may not be vertical...

I get the feeling that you may be using 50 years of small errors cleaned up into one spot.  Making a judgement to move a heavy battery 3 feet would not be my first choice.  But, with the major surgery that has happened you may need to do something.

The C has it's battery in front of the firewall.  When they added FI, the battery moved aft.  Painting and major instrument panel surgery may have moved the CG again.

From the C's POH The distance from the nose wheel to the main wheels is 5’ 6 9/16" same as 66.5625"  the record of the distance to the reference point is not in the POH. Unfortunately, my weight and balance record went with the plane when it got sold..... The reference is the pivot point of the nose gear.  The nose wheel, when it goes over center to lock down, goes into the negative side of the WnB calculation....

Using the weights X arms should give two large positive numbers and one negative number.  Makes sense? 

adding the three numbers together properly (don't lose the negative sign) and dividing by the total weight gives the answer in inches.  This is the inches back from the magic reference point.

Your WnB math should include the airplane's actual weight with it's actual calculated CG

front seats (with sliding range)

back seats

luggage area

hat rack

fuel

oil

Are you using a WnB app?

if you are, do some theoretical moving of the battery and see what happens.

Going through this exercise, you are bound to find the error that has been hiding or the truth behind major surgery...

These are the WnB questions that come to mind of a PP, not a mechanic or a CFI...

Best regards,

-a-

 

 

[C-GHIJ]

Ask your mechanic what the proper way to level the aircraft is.  If he gives you any other answer,  other than deflating the nose wheel to adjust the height, go somewhere else to get it done.  That's how the factory did it.  It is amazing how many mechanics don't know how to weigh an aircraft properly.

[carusoam]

Level using the tail cone seam. There is actually a procedure outlined in the Mooney Maintenace Manual for your plane.

Best regards,

-a-

[RLCarter]

I would start over from scratch (news weights and new arms) and follow the procedures in the book (W&B dated 9-2015 was done with full fuel) book says fuel & oil drained (not calculated). The numbers are not adding up, my guess would be small errors over the years which carried forward each time. You showed the W&B for 1966 and 2015, what about the one just before 2015, what does it show?

[Alyair]

Wow. Thank you all for excellent input. To try and answer some questions. The numbers we have on our current W/B are from a physical W/B that was performed last September after all the work was performed. It was with full fuel and 8 quarts of oil. When calculating for center of gravity I agree that the nose wheel should have a small negative factor. .1 is not a negative factor. I think there is an error there and I wonder if he leveled the plane now. The range of 36.5-44.0 is for pilot seat adjustment I think.

the limitations for cg are 42"-49" aft of datum line. Ref from airplane flight manual. 

[carusoam]

I edited my post.  That is the pilot position.  The photo has some focus issues...

from the new plot posted  42" - 49" are possible. But MGTW is allowed when the CG is between 46.5 and 49.  Shorter than 46.5, the limits to total weight start to occur down 2100 @ 42".  Longer than 49", recovery after a stall may become more of a challenge.

The other thing related to the pilot/co pilot position info is the number of holes in the seat tracks should be accounted for in the arm.  Some seat tracks have gained additional holes along the way...

Check your holes and positions for doing the math.  How much does your CG change by moving the front seats forward?  I have a fuzzy memory of sliding my C's seat forward for WnB purposes while fully loaded.

Are we reading the last graph the same way?  

The Long Body Mooneys usually have the opposite challenge.  The nose is really extended and has a larger engine block.  The WnB is biased a bit to the front.  Putting some cargo in the back can help WnB when there is only a single pilot up front.

Best regards,

-a-

[takair]

I think the nose wheel axel position could end up plus or minus.  We have to remember that in 66 the aircraft had different pucks and the service bulletin to move the axel and avoid touch steering had not yet come out.  This moves that dimension.  I agree with everyone else, need to weigh with aircraft level and equally important, need to drop a plumb bob and get the new axel dimensions.  

[orionflt]

10 hours ago, carusoam said:

Level using the tail cone seam. There is actually a procedure outlined in the Mooney Maintenace Manual for your plane.

Best regards,

-a-

for his airplane it would be the rear access panel seam

 

Brian

 

[carusoam]

Brian, you have me wondering if my tail cone's seam and my battery access are parallel...?

Another good reason to follow the manual.

Best regards,

-a-

[Yetti]

You should start here  http://www.67m20e.com/Mooney%20TCDS%202A3%20Rev%2052%20dtd%209DEC10.pdf

On Page 19 for an E..  the nosewheel support bolts are station 0

For the E:  Leveling means Edge of skin splice over aft fuselage radio access panel. Spirit level is used to level.

 

[Ron McBride]

I was at Lasar Monday, mentioned to Paul that I might reweigh my aircraft, a 69F.  He told me that I will be sorry if I do.  I have heard that we can expect that the plane has gotten heavier over the years.   How many additions have been added with no weight gain, 1/2# pound here and there, new interior, paint, did they remove all of the old electronics and wiring, install new cover plates over the removed antanae's, dirt and grease, etc.

Ron