Twin Dimwatt--8 cells not enough power? Please help!! - RC Groups
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Oct 21, 2001, 12:41 PM
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Twin Dimwatt--8 cells not enough power? Please help!!


I have a Twin Dimwatt I can't keep in the air.

Im running 2 Graupner S400 6.0, 8 x 600 cells, and Castle Creations PEGASUS-35 controller. I have standard rud/ele with HS-81's.

It takes most of the runway to get airborne--and once airborne I struggle to stay aloft. When I try to turn, even slightly, I lose attitude and make a forced landing. So far no major damage other than the wheel popping off the wire.

I know I have the c.g. correct. I made sure to use only hard balsa on the longerons and leading egde of the wing so it can't be that overweight.

Does anyone have any idea what may be the cause? I want to give it more more try before I declare this airframe a lost cause.

Thank you.
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Oct 21, 2001, 02:41 PM
Tork it or Dork it
Ryan Nau's Avatar
I don't think an 8x600ae battery pack is the right choice for the twin dimwatt. You are probably pushing the cells to much with 2 6v400's. Try an 8x800ar battery pack. That should make it fly good. Thats what TomH recommends for it.All of modelairtech planes fly great, I have 4 different ones! And want to built the twin dimwatt later this winter if time with no dihedral and put ailerons on it for areobatics. What props are you using with it? Any pics of it?
ryan
Oct 21, 2001, 06:18 PM
Registered User
Totalboss,

Are you running the two sp 400 motors in parallel off of your battery pack? If you are running them in series each motor will "see" only four cells, and will run too slowly for good flight.

I flew my Twin Dimwatt on seven 1mAh cells (what are now sold as 1250s) and it was more than enough power.

Dick Oglesbee
Oct 21, 2001, 06:22 PM
Registered User
Oops, read 1Ah cells, not 1 mAh.
Oct 21, 2001, 10:29 PM
Registered User
Ryan here are some pics located at

http://photos.yahoo.com/bc/plymouthc...view=t&.last=1

The plans recommended 6 x 3.5 for folders. I couldn't find any that size so I used 6 x 3 Graupner folders.

Dick I have it wired in series per the plan instructions.
Oct 22, 2001, 09:35 AM
LJH
LJH
Moths do not fly inverted
LJH's Avatar
Total,
In series your battery is seeing 20+ amps. The 600AE's are good for no more then 12 or so. Try a diffrent pack, 800AR's, 1300CP's ect. Good luck. I have been looking at some of the Dimwatts and they are pretty cool.

Cheers,
Jim