Weight and Balance info

[WOPR21]

I'm sure this has been discussed already.
I've entered all the forward and and aft limits for my A/C on the weight and balance page and my results always come up RED out of aft limits.
This is driving me crazy since I've tried putting the limits in different lines and still come up red when I know I'm in limits.

Can someone walk my through the input process.

There is nothing I can find on YouTube except for how easy it is to use. Nothing about how to input data.

Thanks

Mike

 

[Stevec]

Hi Mike

You have provided very little information to go on so it’s a bit difficult to give you an answer. I have found the calculator works well so I don’t think that can be the issue. All I can suggest is rechecking the basic aircraft information is correct.

what type of aircraft is it
what is you basic aircraft weight and arm
what units are you using
what is your forward and rear limits
what is the arm for the fuel
what is the arm for the pilot and passenger.
what is the arm for the baggage

Somewhere in there I suspect there is an error that has been entered

 

[jnmeade]

Double check you're using the designated reference point. Some are front of wing, some front of spinner, others in other places.

 

[WOPR21]

Hi Mike

You have provided very little information to go on so it’s a bit difficult to give you an answer. I have found the calculator works well so I don’t think that can be the issue. All I can suggest is rechecking the basic aircraft information is correct.

what type of aircraft is it
what is you basic aircraft weight and arm
what units are you using
what is your forward and rear limits
what is the arm for the fuel
what is the arm for the pilot and passenger.
what is the arm for the baggage

Somewhere in there I suspect there is an error that has been entered

 

[Stevec]

Mike you have entered all the max weights as zero. Try putting in a value that reflects the maximum limits. Front seats say 500 lbs etc.

 

[Marc_J._Zeitlin]

I've entered all the forward and and aft limits for my A/C on the weight and balance page and my results always come up RED out of aft limits.
This is driving me crazy since I've tried putting the limits in different lines and still come up red when I know I'm in limits.

Your empty moment and CG match the W&B you posted. The front seat arm and rear seat arm look to be the intermediate position of the seats - a reasonable assumption, if not perfectly accurate. Baggage is aft of the rear seat, which makes sense.

A couple of comments:

You've provided six images of input screens. But only two of them show weight/CG limits - 3300 lb. and 85.7", and 2233 and 84.7".

Firstly, while the MGW of 3300 lb. and the empty weight of 2233 lb. seem to be accurate given the W&B sheet, there are no indications of what the CG RANGE is - what's the forward CG limit and the aft CG limit? I guarantee you that the range is NOT 84.7" to 85.7", since even the FRONT seats are aft of that.

So the first thing you need to do is find out what the forward and aft CG limits are. Then, you will need at least FOUR "CG Limit" positions/weights. Two that determine the forward most CG at empty and MGW, andn two that determine the aftmost CG at empty and MGW. So, if the envelope is a box, it'll be something like this:

1. weight 2233 lb arm <xx in>
2. weight 3300 lb arm <xx in>
3. weight 2233 lb arm <xx + 7">
4. weight 3300 lb. arm <xx + 7">

or whatever the POH shows as corner points for the envelope. Some aircraft have CG ranges that change with weight, and if that's the case, you'll need to define all SIX of the corners of the envelope.

This is why it's not working - you haven't defined the full CG/weight envelope - all you've given it is a tiny little line (and a CG range that cannot be correct).

It has nothing to do with the max weights at each station.

 

[swatson999]

Have you read the section on Weight and Balance Setup in the installation manual?

> CG LIMITS
▪ A minimum of two CG Limits is required. Typically, enter a CG limit for the forward maximum CG points and a CG limit for the aft maximum CG point. More complicated limits for different weights (such as with a C172) can be accommodated.
▪ > WEIGHT
▪ > ARM

 

[Marc_J._Zeitlin]

Have you read the section on Weight and Balance Setup in the installation manual?

Hmmm. Sorry about that - it's very strange that they don't use minima. But in any case, even so - with the CG limits set to 84.7" and 85.7", any weight in the front or back seat will put him aft of the aft limit. So it's still a CG range setting. His plane cannot have limits of 84.7" and 85.7", only 1" apart. The aft limit MUST be a lot further aft. He didn't post the page from the POH that showed the W&B envelope.

 

[swatson999]

Sorry, I was directing that comment at the OP, not you, Marc. But yes...he hasn't set the fore and aft limits correctly, apparently.

 

[swatson999]

See p. (2) here https://www.wpaviation.com/pdfs/Bonanza_AFM.pdf

 

[WOPR21]

Your empty moment and CG match the W&B you posted. The front seat arm and rear seat arm look to be the intermediate position of the seats - a reasonable assumption, if not perfectly accurate. Baggage is aft of the rear seat, which makes sense.

A couple of comments:

You've provided six images of input screens. But only two of them show weight/CG limits - 3300 lb. and 85.7", and 2233 and 84.7".

Firstly, while the MGW of 3300 lb. and the empty weight of 2233 lb. seem to be accurate given the W&B sheet, there are no indications of what the CG RANGE is - what's the forward CG limit and the aft CG limit? I guarantee you that the range is NOT 84.7" to 85.7", since even the FRONT seats are aft of that.

So the first thing you need to do is find out what the forward and aft CG limits are. Then, you will need at least FOUR "CG Limit" positions/weights. Two that determine the forward most CG at empty and MGW, andn two that determine the aftmost CG at empty and MGW. So, if the envelope is a box, it'll be something like this:

1. weight 2233 lb arm <xx in>
2. weight 3300 lb arm <xx in>
3. weight 2233 lb arm <xx + 7">
4. weight 3300 lb. arm <xx + 7">

or whatever the POH shows as corner points for the envelope. Some aircraft have CG ranges that change with weight, and if that's the case, you'll need to define all SIX of the corners of the envelope.

This is why it's not working - you haven't defined the full CG/weight envelope - all you've given it is a tiny little line (and a CG range that cannot be correct).

It has nothing to do with the max weights at each station.

I got it figured out. I put 6 points in with different weights and CG for the corners of the envelope. Looks accurate now. I still will do a manual WB but it’s nice as a reference tool

 

[swatson999]

6 points in with different weights and CG arms for the corners of the envelope..

Important to use the right terminology...