Help with tail weight on a Tower Hobbies Uproar 40

Hi, I am currently assembling a Tower Hobbies Uproar 40 ARF. I am putting an OS .46FX on it which will put me in a nose heavy situation. A recent article in Model Airplane News reviewed the plane with the same setup.
The author stated he had to "bury 3 oz. of weight in the tail" to get the CG right. Does anyone have a suggestion on how to add weight to the tail with the least amount of destructive re-engineering? I considered mounting the battery behind the wing, but once the wing was epoxied in I'd never get the battery out if necessary. I am also considering adding a battery "hatch" which, with the additional bulkheads and epoxy, might work if the battery isn't too big for the fuselage taper. Your thoughts are appreciated.
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Mounting the battery behind the wing is a good start. Best to have "useful" weight rather than dead weight.
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Paul McIntosh
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I've also seen overpowered Uproars with the rudder and elevator servos mounted on plywood plates near the tail surfaces. Since the Uproar is draggy anyway, you could mount the ply externally.
Morris
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snipped-for-privacy@gmail.com wrote:

I just used some stick on weights and then screws to make sure they don't come off.
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Are you sure the .46 is any heavier than the .40?
First off, can you slide the engine to the rear of the mount and drill new mounting holes?
Next step would be to move the battery aft.
Another consideration would be to eliminate a heavy spinner if you are using one; just stick to a simple prop nut.
And unless you are going for wild maneuvers, a little nose heavy probably won't be noticed.
Cheers -- \_________Lyman Slack________/ \_______Flying Gators R/C___/ \_____AMA 6430 LM____ / \___Gainesville FL_____/ Visit my Web Site at www.LymanSlack.com

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===============Moving the battery is probably the most desirable method. If you use a 'square' battery pack instead of a 'flat' one you'll be able to go farther back before fuselage taper stops you.
It's funny how two versions of a plane are so different. I'm building the Uproar 60 kit and using an ASP-61 for power. The plans show the battery a few inches behind the CG. When my brother brought over his CG machine the battery ended up inside the fuel tank compartment. That probably means I put too much glue in the tail, or that small changes add up when they're behind the CG. I replaced all of the 2-56 control rods with 4-40 and used Dubro adjustable 'steel-stud' control horns instead of the tiny nylon parts that came in the kit.
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Carrell wrote:

Unfortunately, with the ARF, once the wing is in there's no way to get anything in the fuse unless you create a new access hatch behind the wing.
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True, but if it needs to move very far, the square pack might fit better because it's about 1x1 rather than .5x2
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In order of preference:
Move battery back Move engine back (even using different engine mount to bring th backplate bolts up against the firewall) Move servos back
Put on a heavier tailwheel and tailwheel bracket (make any added weigh USEFUL in some way other than just being lead
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Wow, thanks for all the good ideas. So here's what I did... The last three inches of fuselage has a bulkhead installed which made it the perfect place to isolate some weight.I cut the bottom sheeting just behind the bulkhead and the removed that small piece of sheeting back to the tail. I reinforced it with another small piece of balsa and made a hatch out of it - easily secured with a few 4x1/2 screws. I inserted enough lead to get it to balance then stuffed some foam to fill the rest of the cavity, then installed the hatch. I left the lead unglued in case I want to take some out after the first couple flights. When I am happy with the performance I can glue the hatch back down.
Regards, --Mark
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You will enjoy this plane, I flew one for a few years and it was always my go to airplane when I just wanted to have fun. The plane makes you look like a better flyer than you really are. You solved the weight problem exactly like I did, mine was the kit though. I just retired it last week the airframe was just worn out but it still flew great, just looked to ugly to bring out at the field any more. Brad

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