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Saturday 7/7/18

Sat Jul 07, 2018 9:07 pm by Gary M Jones

I was at the field today between 14:00 & 15:00 all on my own , good flying too. There is a dead sheep along the fence line towards the gate from the pits, I saw the farmer so reported this to her. I hope no one had plans for a BBQ Smile .

Farmer …

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advice required

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advice required

Post by Brent Parry on Sat Jul 10, 2010 3:22 pm

With my chief engineer layed up in hospital i need some advice flew the Galaxy Magician the other day for the first time and it is very nose heavy, is it the C O G the same for all planes one third of the wing cord or does this vary, does anyone know where it should be on this model? It seems to require a lot of weight on the tail to acheive this just under 6 oz making the all up weight 5 lb 4 oz, have already moved the battery from the nose to same position as rx under wing? Is this amount of added weight the acceptable. Question


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Re: advice required

Post by melfyn on Sat Jul 10, 2010 5:51 pm

Sujjest you might try contacting Galaxy models as they manufacture the kits they should be able to look up the exact CG from the instructions.

The amount of weight you have on the tail does sound rather a lot even though the model does have a fairly short moment arm and long nose.
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Re: advice required

Post by Brent Parry on Sat Jul 10, 2010 6:08 pm

Thanks Melfyn
I have changed the battery to a square one and positioned it further back under the piolt and added just under 4 oz in the same place and that seems to balance ok with slight nose down at about 20% off the cord from the leading edge.
Will phone Galaxy on Monday tried the web could not find anything Smile

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Re: advice required

Post by Robert Piechulski on Sat Jul 10, 2010 6:44 pm

You can try this program http://translate.google.com/translate?hl=pl&sl=auto&tl=en&u=http%3A%2F%2Fhome.arcor.de%2Fd_meissner%2Fschwerp.htm
if it will be in forein language - just change translation into english Smile
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Re: advice required

Post by Andy Sayle on Sun Jul 11, 2010 11:22 pm

The exact CG position will vary, and there is a lot of factors at work in locating it too. It can differ depending on the wing planform, weight of the model, tail moment arm, tail area, static stability margin required, aerofoil section used, speed of flight etc etc. The best thing to do, is to get someone who knows the aircraft to tell you where it needs to be.

If that is not an option, there are spreadsheets and calculation programs out there to help work out the approximate location for it.

Looking at some pictures of it though, about 30% chord looks to be in the right ball park though, and you can tweak it from there to suit your preference. It is better to err on the side of nose heavy though for the first flights.

HTH
Andy

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Re: advice required

Post by PDQ on Mon Jul 12, 2010 12:18 pm

Galaxy 01473 729279
still do all the kits. Magician and Mystic still sell.
Today they advised for either model
At wing root, measure 1/3 chord. That is the cg position. Yes it has a slightly tapered wing.
Have fun.
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Re: advice required

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