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Old 02-28-2005, 07:57 AM
  #53  
john agnew
 
Join Date: Jan 2004
Location: glasgowScotland, UNITED KINGDOM
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Default RE: new Arf Boomerang 14lb thrust

Guys

Now for the bad news! To achieve the suggested CG of 150 mm back from the leading edge I will have to add 1 1/2 lbs of lead to the nose, this is not good! Alternatively by my calculation a 25 % CG would be 187.5mm back from the LE . The root chord is 450mm the tip 250mm giving an average of 350mm at mid span 25% 0f this is 87.5mm plus the difference between the mean chord and LE is 100mm giving 187.5mm.
This can be achieved with only12oz of lead giving a dry weight of 14lb 8oz with a full hopper tank.

Would any one like to confirm my CG calculation before the model is flown? I cetainly feel that 150mm is too conservative if my calcs. are correct.

To be fair to Allan he suggests moving the CG rearwards after initial flights without giving a specific figure.

John Agnew