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-   -   how to determine w&b during build (https://vansairforce.net/community/showthread.php?t=202232)

Chipper G 12-24-2021 07:05 PM

how to determine w&b during build
 
Is there a WnB program that I can play with that has the kit weight built with nothing installed? I am trying to figure out where to put the battery and LRUs etc

ERJDriver 12-25-2021 05:53 AM

Easy, build a profile in foreflight

rv8ch 12-25-2021 08:59 AM

Quote:

Originally Posted by Chipper G (Post 1577557)
Is there a WnB program that I can play with that has the kit weight built with nothing installed? I am trying to figure out where to put the battery and LRUs etc

This W&B excel sheet was shared a few days ago:

https://docs.google.com/spreadsheets...f=true&sd=true

You can play around with it if you can measure the arm of the battery and other things you want to simulate.

PilotjohnS 12-25-2021 09:48 AM

My struggle
 
Quote:

Originally Posted by Chipper G (Post 1577557)
Is there a WnB program that I can play with that has the kit weight built with nothing installed? I am trying to figure out where to put the battery and LRUs etc

I am struggling with this too. I have made so many changes as compared to the "samples " out there that I am at a lost for any indication if I will be tail heavy.

Foghorn 12-25-2021 07:51 PM

I used this manual by I-LUKE. You’ll have to convert from MM to inches. Just add/subtract your equipment and it will give you some idea of your potential W&B.

https://vansairforce.net/POH/Luke.pdf

N82VM 12-26-2021 08:00 AM

Quote:

Originally Posted by Foghorn (Post 1577687)
I used this manual by I-LUKE. You’ll have to convert from MM to inches. Just add/subtract your equipment and it will give you some idea of your potential W&B.

https://vansairforce.net/POH/Luke.pdf

I have looked at this one too. However, being FP is there a crush plate, or even a weighted crush plate? Not having that info significantly changes the calculations especially with the arm of the prop. Would be nice to know in order to make the right calculations simulating different prop combinations.

Chipper G 01-04-2022 07:46 PM

Quote:

Originally Posted by ERJDriver (Post 1577580)
Easy, build a profile in foreflight

agreed a completed plane in foreflight is really easy i am talking about a skeleton airframe with nothing but the sheet metal and glass done with that base wnb you can calculate every once and where it goes prior to just throwing parts at it and hoping its close at the end.

Chipper G 01-04-2022 07:48 PM

Quote:

Originally Posted by PilotjohnS (Post 1577617)
I am struggling with this too. I have made so many changes as compared to the "samples " out there that I am at a lost for any indication if I will be tail heavy.

yes i have found a lot of done ones but they wont match me by 200lbs or so.

rv8ch 01-04-2022 11:44 PM

Quote:

Originally Posted by Chipper G (Post 1579952)
agreed a completed plane in foreflight is really easy i am talking about a skeleton airframe with nothing but the sheet metal and glass done with that base wnb you can calculate every once and where it goes prior to just throwing parts at it and hoping its close at the end.

The principles don't change at all if your aircraft is complete or not. The details of how to do a W&B are published in a lot of places, here's a good one:

https://www.eaa.org/eaa/aircraft-bui...ht-and-balance

Once an aircraft is complete, the variable parts are typically weight of people, fuel, and baggage, and their distance to the magic "datum" point.

To change the location or weight of something like a battery, you add a new variable part to the spreadsheet with its distance in the two proposed places, and you will have a new W&B calculation.

It's actually easier to do than to explain, but hopefully after reading Ron Alexander's article above it will be clearer.

michjor 01-05-2022 09:37 AM

If you're hangered at an airport, you'll likely find someone there with a couple of scales, most A&P's will lend them out no charge, and you can weigh the plane on L/R wheels at the same time to get an accurate reading.


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