General CG with the battery installed

coolgabsi

Super Mod & DEAL KING!
Ok. I instlled the battery in my nexstar mini EP . tried to stick it as far forward as I thought i could, and still.. a ta bit tail heavy.... just barely sits on the nose wheel.. I have to touch it on the tail and it falls back...

Should I use a weight in the nose? Something like that? How / where to place it!

Suggestions! :)
 

RandyDSok

Well-Known Member
Where indeed...

The answer to this will be different from airframe to airframe and several factors need to be considered before you decide.

The most ideal location for a battery would be at the centerline of the airframe with the centerof the battery tray right on the center of gravity. Due to structural requirements ( like say a wing tube that sits at the CoG perhaps ) and weight considerations, the ideal location is seldom available so usually the battery location ends up in front or behind the CoG which makes which weight of battery you use affect the CoG.

This means that the plane will have only a few sizes ( weights ) of batteries that will allow the model to achieve a proper CoG. If you select a battery that is heavier or lighter than the recommended sizes... that means you will have to offset that weight somewhere. Adding any additional weight will always affect the flight performance/characteristics as well as as well as increase the chance of damaging the landing gear and it's associated structures used to support the LG.

So first you want to find out why the model isn't balancing at the recommended CoG... Did you add too much weight in the tail... If so the answer is easy, permentantly add weight forward of the CoG, add it as far forward as you can so you don't have to add as much weight and simply glue it in with epoxy or similar glue.

If the issue is caused by you using a battery that is heavier than recommended, then the so called easy answer is get a lighter weight battery... If you can't, then you will need to add weight to a location you can get to easily ( like in under the wing area forward of the CoG ) in order that you can remove that weight later for times when you aren't using a heavy battery. You could perhaps attach the added weight with some velcro or whatever you can consider that can be easily removed later.

Good luck on whatever direction you decide on. It is something you need to think about before you decide.

Randy
 

coolgabsi

Super Mod & DEAL KING!
I am using a 1200 instead of a 1250 (recommended) breeze... I mean it is a bit lighter but why not use it if you have it right??? lol ... apart from that..

the battery sits in front of the CoG... it is supposed to make it nose heavy.. I will be going out to buy the right size battery for a second but I wanna learn this.. and this is good.. if i had used the perfect battery from start, then i wouldn't have asked this.. see see see.. :p :p lol hahaha

anywaz... randy.. I will try add some weight, but what do you think I can use as weight? Any ideas? The only "weight" i added to the tail was two drops of hot glue on the vertical stabilizer. But thats it.. Its all stock.. let me know y'all! :)

thanks
 

RandyDSok

Well-Known Member
Find out how much weight you need to balance... and add it onto the battery itself perhaps.

It can't be that tough to figure out what you can use for additional weight.. a big washer, a tire weight, a dime, a nickel ( which is 5g btw ) ... the list goes on.

Each make and model battery will differ in weight... The recommended one is 124g but that is just a ballpark figure that could change with different connectors for instance. Still it is a place to start... so weight the battery you have... compare it to the recommended weight and add the difference to what you've already got.

Oh... The weight of wood also differs conciderably... so it may not have been caused by your assembly, it could just be that your model has wood that is a little denser in the tail of the plane that normal.

Randy
 

breeze400

Spagetti Pilot
The do have model weights at the hobby shop. They look like car stick on wheel weights. Just figure out how much weight you need then, peel and stick! Lol I was just needling you! Hahahehe!
 

Tony

Staff member
Travis, I have two AA's in the nose of my Edge 540 for balast.

Sam, whenever you add lead weights, never trust the sticky backing that comes with it. either epoxy it in place, or use a ziptie. I used two zipties after taping it in place.
 
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