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Author Topic: Am I in the Ballpark?  (Read 876 times)

Offline Dennis Saydak

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Am I in the Ballpark?
« on: January 15, 2011, 06:13:07 PM »
I have a Brodak 1/2 Pathfinder almost ready to cover. I don't have a clue as to what it should weigh or what weight a Big Mig .061 can handle. So far the weights of all the components total 294g / 10.37 oz. Wheels, spinner, pushrod and finish aren't included but everything else is including the engine prop & tank. How's the weight so far? I still have the option of lightening up the structure by hogging out the fuselage & stab if necessary.
Just when you think you're getting ahead in the rat race.....you find the rats just get faster! MAAC 13120L

Online Larry Renger

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Re: Am I in the Ballpark?
« Reply #1 on: January 16, 2011, 08:32:31 PM »
The Big Mig should be good up to about 12 ounces, then you have to start going to shorter lines.  At 12 oz. with a 5.5x2 APC prop or Cox 5x3, I would think you could fly 45 ft x .008 lines with ease.

If weight gets up to 14 -15 ounces, you are no longer going to be competitive, but will be safe and have fun on 40' lines.
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline Dennis Saydak

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Re: Am I in the Ballpark?
« Reply #2 on: January 17, 2011, 09:24:58 AM »
Thanks Larry. I'll make the lightening mods as shown on the plan as a matter of necessity. The wood in the kit was very decent quality and I normally build fairly light but a little extra effort will pay off in performance.
Just when you think you're getting ahead in the rat race.....you find the rats just get faster! MAAC 13120L

Offline minnesotamodeler

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Re: Am I in the Ballpark?
« Reply #3 on: January 17, 2011, 03:48:16 PM »
The Big Mig should be good up to about 12 ounces, then you have to start going to shorter lines.  At 12 oz. with a 5.5x2 APC prop or Cox 5x3, I would think you could fly 45 ft x .008 lines with ease.

If weight gets up to 14 -15 ounces, you are no longer going to be competitive, but will be safe and have fun on 40' lines.

That's just what I was gonna say, 12 oz. is about the limit for ideal performance.  A .061 will fly more weight than that but will tend to be underpowered. I think my heaviest was an earlier LittleAxe at about 15 oz.  it had a lot of wing, thick airfoil, flaps and flew pretty well but could have used more oomph for sure.  Same plane at 12 oz. makes all the difference.
--Ray 
Roseville MN (St. Paul suburb, Arctic Circle)
AMA902472

Offline Dennis Saydak

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Re: Am I in the Ballpark?
« Reply #4 on: January 22, 2011, 12:20:57 PM »
I've lightened up the stab & fuselage but I have yet to do the same to the flaps. The weight saving so far is 6/10 oz ( 5% of the target weight). Perhaps that's not all that great but when you consider the target weight of 12 oz is it rather in?-significant? The saving may be potentially cancelled by added tail weight (if needed). I don't know if these build nose or tail heavy. I'll also do more sanding on the fuselage and I will also trim some material off the nylon hinges for additional weight saving.
Just when you think you're getting ahead in the rat race.....you find the rats just get faster! MAAC 13120L

Online Larry Renger

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Re: Am I in the Ballpark?
« Reply #5 on: January 22, 2011, 08:12:08 PM »
Sewn hinges (do a search, they are well documented) add approximatley NO weight.  They also add NO friction!  What's not to like?  My controls will droop to full deflection when I turn my models over one way or the other (if I have done everything else right)  This is crucial for small models.  We don't need no stinkin' line tension (if the control system is perfect!!!)   S?P  VD~ CLP**
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!


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