View Full Version : Balancing the ECO 8
I've noticed that many of the ECO 8's I've seen on the web have the reciever and gyro behind the motor, and only the speed control in the front. I know that this is done to separate the reciever as far away from the motor as possible to minimize interference. Also most of these are using the tail pipe mounted tailrotor servo, as well.
When I first built my ECO, I set it up in this same way: Tail rotor servo on tail boom mount, Gyro on tail boom mount, reciever on the top behind the swashplate, and speed control on the front. I'm using a BEC, so there's no reciever battery. The problem was that I had a very hard time balancing the ECO properly without adding a lot of weight to the nose. I even moved the reciever to the front to help balance it. Even doing this, I still needed to add 2.25oz to the front to balance it properly. Also, I have to put my battery pack in so that it's as far forward as it can be without falling out.
For those of you that are using the rear mounted motor/gyro, how did you balance it? Did you have to add a lot of weight, or are you just flying it with it imbalanced? Also, I'm flying without the plastic body. Does that contribute much at all to the CG location?
The NiCd location is important for the balancing, I think so.
When I use 10cells, the CG balance is no problem. But, when I use 8cells, in order to move the NiCd battery forward, I must have made an additional extension plate for the battery mount.
Certainly, I had mounted the photo on my site..(ECO8 >> acrobatic flight page)? But, sorry, at present, my site is not available, due to server system maintainance. In a few days, it will be re-started.
[This message has been edited by Tohru Shimizu (edited 04-24-2000).]
Thanks. I had thought about moving the battery forward too, but none of the ones I've seen had the forward mount, so I was thinking that it must have just been a problem with my setup. I'm glad to hear that it wasn't just me with the balance problem.
I'll look for your page sometime later and see how you did it.
That also means that I can move my reciever back to where it was!
I know that it was a while ago, but how did you end up getting the balance right? I have just started and come accross the same problem.
On both my 8 cell Eco-6 and 10 cell Eco-8, I have the equipment layout you describe. I have my cells o-ringed to the front LG battery mount and use the hooks on the front of the frames for rubber-banding the front of the pack.
I like to keep my packs short to minimize stress on them and also to keep the weight concentrated.
My 8 cell packs of 1300 and 1700 CP cells are arranged in two sticks of 4 cells side-by-side.
My 10 cell packs of 1700 CP cells are arranged in two sticks of 4 cells as above with a short stick of 2 cells nestled between and below them.
My 10 cell packs of 2400 CP cells are arranged in 2 sticks of 3 cells side-by-side and two sticks of 2 cells side-by-side below them.
On the 10 cells Eco-8, I have cut out a section of the bottom of the canopy to clear the hump of the packs.
My 2 cents.
Greg in Minneapolis
I have a separate RX battery pack made up of 4 x AAA NiMH cells. These are mounted on two plastic booms which protrude way out the front of the frame (actually borrowed two pieces of my son's K-NEX) so that when the canopy is fitted the battery pack is situated right at the very front of the canopy. This balances the ECO.
The advantage is that the energy used by the radio/gyro/servos is not being supplied by the main pack. This saves approx 0.2AH capacity in the main pack during a typical 10min. flight.
to solve this problem on my heli (ECO 8 +10 cells+brushless motor MEGA 22/20/4,90°CCPM)I engineered and made a forward battery fixing system.
It is very simple to make and only need to open the canopy to permit the battery pack to move forward.
With this mod ,no need of extra weight in the nose !!! images/icons/wink.gif
I you want I can send you some pictures of it.
My problem is that the battery is as far foward as it will go, by using both battery (straps?) as supplied in the kit.
Can you hold the batteries in using just the front strap, or is there a mod for that?
Please send pic for reference
My battery mounting mod use only the forward original battery strap (rubber band) and an added rubber band+ a mount on the forward of the frame .
With this combo I can move forward my pack for 6/7 cm from the original location .
Send me an e-mail and I will e-amil you by return some pics of it.
It very simple and cheap to build (2 pieces if rubber foam,2screws,1rubber band,1 piece of plastic) images/icons/wink.gif
And it works perfectly.
The only sensible point is to open the canopy in the front to permit the battery to pass thought .
The holes for this mod exist already on the 2 side frame.
Wow, it's been a long time since I've been to the message board. Well, I made a few mods to the ECO, which probably helped balance it out, although that wasn't my intention.
I bought a carbon rod and used that for the tail rotor pushrod. I doubt that helped shift things much.
In the front, I chopped down the front end to remove the shelf right in front of the motor. The end result is that the front is the same height as the far-front section, which allowed me to mount my speed control lengthwise and a little further forward. I don't think that did too much either, though.
I was originally running the BEC off my speed controller with 10 cells, which was exceeding the manufacturer's recommendations. Rather than put a battery on it, I mounted a group of four voltage regulators with heat sinks on the front. A homemade BEC. My reason for going this way is for convenience. I don't have to ever charge a receiver battery, and I don't have to worry about checking the battery or it dying in flight. That added some weight, which probably accounted for the rest.
I currently have it so that the battery is pushed forward as far as it will go, but so that it is still mounted in the rear battery mount. (I'm using 2000mAh 10 cell packs, 5 cells long, end soldered) I like the idea about making a mount on the front section of the frame. I'll probably do that once I get around to flying it again. (I have too many hobbies)
My balance was out also with 8 Cells. Solution is very simple. Have the battery secured at the back by the front O ring and at the front with an elastic band to the front of the frame. My battery sticks out about 2cm beyound front of frame to get CG under mainshaft but is not too far forward to need a hole cut in canopy. Have used this for a 9 months now with no problems.
Some pictures and infos about my battery mod are awaiting you in your mail box images/icons/wink.gif
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