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how to determine w&b during build

Chipper G

Well Known Member
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
 
My struggle

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.
 
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.
 
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.
 
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.
 
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-bu...rticles/weight-and-balance/weight-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.
 
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.
 
Thanks for the info but not what I am looking for. When you manufacture a Gulfstream for instance, they know where ever part is going and what it weighs prior to the build starts. I wonder if Vans has this skeleton weight so as a builder I can put my specific engine prop avionics combo and then I can determine where everything goes. I don’t have wings on mine yet so weighing it is not that simple. I guess I could put the wings on it and do a WB but I figured this has been asked before and would be easy to get.
 
I don't think you'll find the consistency you're looking for. Unlike Certified aircraft, Experimentals we can do what we like, and as builder document it, like putting an electric motor from a motorbike on the front with salt water batteries as the power unit.

Vans provides the baseline to calculate the CG, you'd need to become the "manufacturer" from that point on.
 
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