Weight and balance question

[jetpilot12]

I have a 1963 M20C and I use the eFlight program for my weight and balance.

On my last flight, I was loaded with 4 people, 60 pounds of baggage and full fuel (48gal).

I was below my gross takeoff weight, useful load and within the C.G. envelope. I did have an aft C.G.

In cruse flight the plane was trimmed with full nose down and still wanted to climb (50ft per min).

Is this normal or does my trim need to be readjusted?     

[carusoam]

That is not normal from my '65C experience. (52 gallons of fuel on board)

Peops...170X4=680

Baggage...60

Fuel...6X48 = 288

Total...1028

Check our math (yours and mine)

My 65C did not have that kind of Useful Load.

When I put a family of four in it, the two in the back totaled about 100pounds.

I was able to fly long distances with three people and 60 pounds of luggage, but less than full fuel.

You may consider doing some precision math because you are probably approaching the limits of weight and balance and useful load.

When was the last time the plane was weighed? Now is the time to get an honest answer for yourself...

Like I said, my math may be mixed up.

But your math, combined with the situation you described, is lighting a proper cautionary light!

What was the actual weight of the four people?

Do you have the old ADF wire on the top of the tail? If it doesn't have a really long spring, it can keep the tail from going all the way back... Imagine trimming full forward and having the tail suspended by the ADF wire! This was one of my early C experiences...

Next thing to check full motion of the trim. This can be done on the ground. Old grease is known to dry and hang up in the jack screw over time. This has a tendency to limit the travel of the trim.

Use your POH to do a weight and balance. I have difficulty using weight and balance programs. The more simple they are to use, the more dangerous they become regarding miscalculations...I compared my results with my CFII's until we were both getting the same result as the POH.

From the C's POH...

"The front seat positions can adversely affect CG limitations at the most rearward loadings. Allowable baggage weight may be dictated by seat positions..."

Max gross weight 2575 LBS

Forward CG limit, 2100 LBS @ 42”

Forward CG limit 2575 lbs @ 46.5”

Aft CG limit all weights @ 49"

Know the datum is the nose gear attaching bolt...

Use the POH to get all these details. The entire envelope is 7" long.

Use the aircraft logs (normal for 1965?) for the details of the CGs for seats, people, baggage, hat rack and fuel...

Note: I am only a PP, not a CFI or aviation expert. I am trying to be helpful.

How did I do?

Best regards,

-a-

Update:

With your weight and balance program...

Does it graphically show multiple solutions from Take-off to touch down and include data for extending the flight until all fuel is exhausted?

If it shows any data points outside the envelope, it is time to identify what is happening.

[ryoder]

Full fuel full people and bags doesn't work in almost any airplane. This should be a red flag for all pilots in all airplanes.

My C can do two 200 lb in front, one 170 in the back, full fuel and 50 bags. That comes out to 570+312+50=932. I have a bit more useful load left over with this loading but basically I consider three and full the max and not wanting to get near maximums I'll fly with a bit less gas if I have three on board.

[Glenn]

Exceeding aft CG, on purpose or inadvertently can be mortally dangerous.    

 

If you exceed forward CG, you may thump the nose gear on landing. Exceeding aft CG can lead to irrecoverable stall, and we all know what that can lead to.  

 

Please double check your numbers and if they do not make sense have the plane weighed.  If you are like most of us with older airplanes, your maintenance logs may have almost 50 years of additions, subtractions, and even some long division. Remember a lot of this figuring would have been done before the widespread use of calculators.

 

Please forgive me for sounding a little over the top on this, but what you have described can really be dangerous.

[1964-M20E]

After you have double checked all of your math and maybe weighed the plane and the extras you have in the baggage compatment you should have the rigging checked and verified.  It is not difficult and you can do it with your mechanic you just ned to get a set of travel boards.  Hangar tool box rents them.

[jrwilson]

Mine, a 1963, with 48 gallons tanks, was within CG and Gross weight with 4 x 170 pounders, full fuel and 19 pounds of baggage.  You're likely too high in baggage weight...  But to your question, with that CG you should have plenty of trim...you should get your trim adjusted...

[cliffy]

Just a few questions trying to help out

What is your listed empty weight and CG position?

WHat is your listed useful load?

What was the actual weights and what seats were your pax in?

Did you actually weigh the bags or just guess? (we all do that)

Did you actually weigh your pax? (none of us do that but they all lie about it)

A few pounds here a few pounds there and start to get into some real weight(especially when

we get near max numbers).

Have you doubled checked your fixed inputs for your W&B program? Are they correct?

I had mine weighed and found an error on the original W&B from the factory no less!

You will have a couple of items to check on your trim system.

One will be the actual "throw" of the stabilizer from up to down

The other will be the static setting of the elevator when set at the required stab position.

You can find them both in the TCDS sheet for your airplane.

By your screen name I'm going to presume you know how to do W&B

What you describe is not normal

[jetpilot12]

This is a sample weight and balance using the eflight program. All weights were taken from the last weight and balance in the aircraft log book. The aircraft is in the paint shop and will be weighed when it come out. Thank you to everyone for your input.

 

Jon

N6758U Weight & Balance Sheet.pdf

[carusoam]

Jon,

I'm not seeing a couple of key components...

1) where the weight of the individuals in the front seats are.

2) where the position of the front seats are. There are a couple of holes in the rails. Did you use the most forward ones for the flight?

3) the effect of fuel on the CG. It clearly moves as the tanks empty. The graph isn't showing it.

It appears there is one weight for the four people?

At the limits, the calculation and real life situation is serious business...

If these details are really missing, don't sign the line at the bottom of that page...!

Do you have arms (for your plane) for the front seats, back seats, fuel, baggage and hat rack?

Did you use the proper arm for the sliding seating position?

Do you really have four FAA standard people?

Do you understand the dangers of having an aft CG?

Relying on trim to keep the plane flying after an inadvertent stall would be disastrous.

Using an M20C to fly with four ordinary people is a challenge. Adding full fuel adds to that challenge.

Not knowing if it is the trim system is not working properly, or the weight and balance calculating system is not working makes it time to continue to dig deeper.

Again, I am trying to help. My friend Patrick would want me to...

Do you check the density altitude before Take off when fully loaded?

Best regards,

-a-

Pm sent...

[Marauder]

This is a sample weight and balance using the eflight program. All weights were taken from the last weight and balance in the aircraft log book. The aircraft is in the paint shop and will be weighed when it come out. Thank you to everyone for your input.

Jon

To answer your question, my trim is typically pretty nose down even if I am forward loaded. I loaded up my W&B for my F parameters. No way I could fly with 4 people (even lighter weight people), 60 lbs, and full fuel. Here is what my plane would look like configured the way you did it:

Sent from my iPad using Tapatalk

[Hank]

Another consideration is seat position. My C has three locked positions, and the Owners Manual gives moment arms for each one.

[carusoam]

Chris,

Thanks for sharing the detailed W&B.

That is what i'm missing from Jon's post.

Hank,

Where are your arms printed??? My 65’ C had a loose graph included in it's logs. I don't recall the details.

I can't find the details in my C POH. The AFM went with the plane...

Best regards,

-a-

[Hank]

My Owners Manual is posted here. I'll check it when I get a few minutes.

[Guest]

Full fuel full people and bags doesn't work in almost any airplane. This should be a red flag for all pilots in all airplanes.

My C can do two 200 lb in front, one 170 in the back, full fuel and 50 bags. That comes out to 570+312+50=932. I have a bit more useful load left over with this loading but basically I consider three and full the max and not wanting to get near maximums I'll fly with a bit less gas if I have three on board.

I'm glad you said most airplanes. My Comanche will carry 780 pounds of fuel and 720 pounds of people, verified by a recent re-weigh. 2100 pounds empty, 3600 gross.

Clarence

[M20F]

I can do 48 gallons, 4 x 160lbs, 60lbs of baggage, and 2lbs in the hat rack and be maximum weight/aft CG in my F which is recently weighed/calculated. I can't see how you could do it in a C would redo the math or reweigh the plane as something is off.

[jetpilot12]

OK Guys,

 

First, "Thank you for everyone's concern". Yes, I do understand the effects of an aft C.G. (That's what generated the question).

Not that it matters, but my background is ATP fixed wing, ATP helicopter, CFII and A&P. 12K plus hours. 200 in Mooney's (50 in mine)

 

I do feel I have found most of the problem. During the last annual, two of the trim torque tubes were changed.

After a little research, I have discovered that the tubes were not installed correctly. Not allowing proper movement of the trim.

If anyone can see something I'm over looking, please let me know. It doesn't matter how much experience we have, we can always learn more

Please tell me if my numbers look wrong.  

 

 

 

ZFW            1544

Pilot             165

Co-pilot        205

passenger   130

passenger   120

bags              60

 

TOW =         2552

 

MTOW   2575 

ATOW - 2552

               =23 pounds under GTOW

 

Here are all of the specs that were given to me when I bought the plane:

 

Max takeoff weight 2575

Empty weight 1544

Useful load 1031

CG gear down 42

CG empty 45.3

Most aft CG 49

48 gallons fuel  

Datum 33in forward of leading edge (inboard edge of stall strip)

[ryoder]

I'm glad you said most airplanes. My Comanche will carry 780 pounds of fuel and 720 pounds of people, verified by a recent re-weigh. 2100 pounds empty, 3600 gross.

Clarence

I am pretty sure the 182 is also able to carry four people and full fuel and bags because my coworker reminds me of it every day it seems

[JaredDavis]

I ran the weights and fuel given through my 65C chart. It looks OK to me. It is right near max weight on my plane.

 

Got any details on how to identify tubes installed incorrectly?

 

PS I think you left fuel out of your text, but included it in the GW.

PPS 52 gals would be over weight on my plane

[cliffy]

Please advise which of the "trim torque tubes" were changed.

Are you referring to the two spring bungee tubes that attach to the elevator horns themselves?

If so there are a couple different ones, they being s/n specific.

Also their adjustment may seem confusing at first but actually its an easy adjustment.

The take off trim indicator may be another matter as the early MMs don't specify how to set it.

There is a way how ever.

[Guest]

If he is referring to the trim torque tubes in the belly I've seen this be fore as well. We ordered replacement tubes for a J model only to find out that previously someone had replaced them and put them in the wrong places. Getting the system out of rig happens during installation when the tube are allowed to turn changing the tail position or the wheel position. This can only be corrected with a travel board.

Clarence

[cliffy]

Yup, either end can screw things up if they get changed and not re-adjusted correctly.