Weight and Balance help please

[Paul 5r4]

I've downloaded the Aviation W&B app from iTunes. It has great reviews! I'd like to put the numbers in for my 7A but find I'm getting confused. Would appreciate any help.

Here is snapshot of the sample graph they give. I'm suppose to use it as an example to input the numbers for my airplane. Some of the points I can get but points 1, 2 and 3 I'm not sure how to come up with. The CG range for the 7A according to vans is 78.7-86.82. The empty weight CG for my aircraft is 81.52. Are points 1 and 2 suppose to be 78.7 or my aircrafts empty weight CG of 81.52? Also, I know the Weight at point 1 is my aircrafts empty weight but where does weight for point 2 come from.... The weight for point 3 is the max gross weight but how do you come up with the ARM to input. Point 4 max gross wt and most aft CG from vans numbers and point 5 empty wt and vans aft most CG??? Thanks in advance for helping me clear my head!!!!

[BobTurner]

The graph you show is very common, where a more forward limit is allowed at lower weights. However, Vans does not allow that. So use the forward cg limit (78.7") for points 1, 2, and 3. Point 1's weight is your empty weight; point 3's weight is your gross weight. For point 2 just pick a weight anywhere between empty and gross. Point 4 is maximum aft limit (86.82") and gross weight. Point 5 is 86.82" and your empty weight.

[scrollF4]

Bob, Why not just delete point 2?

[Raymo]

Here is a link to a spreadsheet style W&B for an RV7A I found somewhere (maybe here). Note the rectangle shape of the load range.


https://drive.google.com/file/d/0B9G...ew?usp=sharing

[BobTurner]

Originally Posted by scrollF4

Bob, Why not just delete point 2?

Because I have no idea what the software would do with a missing data point.

[az_gila]

Originally Posted by BobTurner

Because I have no idea what the software would do with a missing data point.

Then make point 2 and point 3 the same value. The sw should be OK with that.

Update, Looking at the screen in your first post, it looks like the "extra" points are just set to "0,0", just like Point 6.

Make point 5 0,0 and just use your four points in the definition.

[Mike S]

Advanced Flight Systems has a really nice W/B program built into their units. At one time it was offered on the I tunes store, but I seem to recall it had a bug and was removed. I do not know if it was ever fixed and offered again, but if so, I would surely buy it for our Ipad. https://itunes.apple.com/us/app/weig...430996589?mt=8

Rob??

[Larryskydives]

That is just a sample. Depending upon the envelope for your aircraft you may only have 4 points or 6 or more. Dependent on your aircraft.

Go to the Airplane Template Library and there is already a 7A W&B to download. You will just change the weights for your aircraft.