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04-07-2015 06:40 PM | ||
kip51035 |
Re: CG calculation by weight Here are the formulas from the Standard Aviation Maintenance Handbook. The 5"X7" blue book. I also have a spread sheet that does the calculations, but unfortunately it is on my typewriter. |
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04-07-2015 10:02 AM | ||
Phil202 |
Re: CG calculation by weight Awesome! BTW, you did a very job on your calculation sheet! Cheers |
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04-07-2015 10:00 AM | ||
grosbeak |
Re: CG calculation by weight No arguments here... |
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04-07-2015 10:00 AM | ||
Phil202 |
Re: CG calculation by weight Thanks David! |
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04-07-2015 08:15 AM | ||
davidmc36 |
Re: CG calculation by weight Phil is right. If you do not have something within the program to calculate the shift of weight due to attitude it will throw some error into it. We did a 737-400 a few weeks ago and the program is set up to enter the attitude based on the plumb-bob in the wheel well and correct the COG. |
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04-06-2015 01:54 PM | ||
Phil202 |
Re: CG calculation by weight Quote:
Not to argue, but if we are to show how to do CG by weight, might as well do it correctly. I'm an Aircraft Maintenance Engineer myself and i don't quite agree with that... For a nose wheel aircraft it won't make a huge difference but for a tail wheel aircraft like a Extra300 or similar, when you get into large scale and you want precision, it does make a difference... Think of pendulum, if you till the support the weight will remain the same but is position will change in regards to its support. So, having the tail down or up will affect your resulting CG location... Cheers |
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04-06-2015 01:21 PM | ||
grosbeak |
Re: CG calculation by weight Quote:
You might notice in the picture that the fuselage of the aircraft isn’t level. So long as the aircraft attitude is the same as each measurement is taken, and the CG distance is measured horizontally along the table top, the method will produce results that are accurate enough for our purposes.That said, I do prop the tail up to imitate level flight... just make sure you remember what you used to prop it up so you can get repeatable results. |
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04-06-2015 12:40 PM | ||
Phil202 |
Re: CG calculation by weight Answer is yes, Mike, you simply use the measurement of your nose wheel instead of tail wheel... I have a very similar excel sheet that i made a few years ago, only being using this with great success, only thing i would add is that the plane should be in "level flight configuration" when all measurement and weight are carried out. I don't know how to share an excel document, but feel free to send me an email if you want it... phil.dessureault@gmail.com Cheers |
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04-06-2015 12:02 PM | ||
Mike Sebastien |
Re: CG calculation by weight Will this work for a tricycle gear aircraft? |
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04-06-2015 10:24 AM | ||
grosbeak |
CG calculation by weight I like to calculate the CG of my tail draggers by weight, and I have created a new and simplified version of the spreadsheet to do so. All credit for the method I use goes to Tom Hastie's article. The spreadsheet is available to view by all at CG Calculation template; you have my permission to copy it and use it as you like. Here's a look at the layout. Here are the steps I use to calculate CG: First time with this airplane
Subsequent times with this airplane
Notes:
Feel free to respond here or PM me if you have any questions. |