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Dirty Birdy Balance

Old 08-06-2013, 12:11 PM
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Pylonracr
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Default Dirty Birdy Balance

I started building a Dirty Birdy 60 from RCM plans. I remember reading somewhere that they all came out either nose heavy or tail heavy. I plan on using retracts in mine and would like to move any weight around early in the building process if I know which way to go. Anyone have experience here?

Thanks
Scott
Old 08-07-2013, 10:45 AM
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Skylane
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Using an OS 61 SF I found that the DB ARF was noseheavy and had to add about 3.75 oz of lead to the tail. Others have had similar results, although it does depend on the engine used. I don't know if this is applicable to a plans built DB.

Jeff
Old 08-07-2013, 12:29 PM
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Pylonracr
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It will certainly help.
Thank you
Old 08-07-2013, 01:16 PM
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Consider moving the RX battery pack to behind the wing. When you can move something that heavy from in front of the CG to behind the CG it makes a huge difference in the balance.

Mike
Old 08-07-2013, 01:17 PM
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Jim Johns
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The same applies to the Bluejay Dirty Birty kit. It also builds nose heavy from all reports. I'm building this kit now and plan to put dual elevator servos under the stab to counteract the nose heaviness.

If you are using the hardwood bean motor mounts instead of the nylon radial mount, that will probably make things even worse.

Originally Posted by Skylane View Post
Using an OS 61 SF I found that the DB ARF was noseheavy and had to add about 3.75 oz of lead to the tail. Others have had similar results, although it does depend on the engine used. I don't know if this is applicable to a plans built DB.

Jeff
Old 08-07-2013, 05:15 PM
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I put two rx battery packs just in front of the stab on my Bluejay DB and it balanced nicely with an OS61fsr out front.
Scott
Old 08-08-2013, 04:32 AM
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My Dad's ARF needed 4 oz of lead in the tail with battery and retract tank as far back as possible in the radio compartment. He is running an OS 61FX.
Old 08-09-2013, 08:17 PM
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Pylonracr
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Thanks for the help guys. Looking at the plans it seemed like it was going to be nose heavy, and I thought I remembered reading that they all were nose heavy. I will move as much as I can back as I build it.

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