U Can Do 3D
 

Hey All,

Hope everyone's having a great one. I am just about ready to install radio in my U Can Do 3D. I was wondering if someone who has built this plane could enlighten me and tell me where about they placed the battery pack to balance the plane. I am using an O.S. .91 four stroke for power. I have never built a plane with so many servo's in the rear and I will be the first to admit that I don't have a clue as to where the battery pack will go in this sucker to achieve proper balance. My hunch is that it will go somewhere forward of the wing saddle. Just not sure though. Thanks much to anyone who can give me an idea.

Jeff

U Can Do 3D
 

Check out the huge thread in the 3D forum.

Also check out the online review on mian page. You should find anything you need there.

U Can Do 3D
 

With an OS 91 FS up front

I placed my reciever and battery to the rear of the compartment that is visible when the wing is removed.

I would have moved it farther back but I did not want to take the time to make a hatch. So I added 3 more ounces to the tail

I was shooting to have the CG at 6".
I am at about 5 or so now.

OS 91 FS just isn't enough power for me.

If I had it to do over again I would go with a saito 100.

U Can Do 3D
 

Every plane will be different depending on things like how much glue you used, what kind, etc.

Just stick it in somewhere and check the balance. If it's wrong, move it.

U Can Do 3D
 

Hey Bz,

Thanks for the info. Sure appreciate it. Unlike Mr. Minnflyer, at least the information you provided gives me somewhat of a starting point.

By the way Minnflyer, I have built enough planes to know that if the balance is wrong, I will have to move the battery one way or the other to accomplish the task. I was simply hoping that someone would give me some sort of starting point. And thanks to Bz, I now have it.

Jeff

U Can Do 3D
 

Sorry Jeff, it just seems to me that by the time you post a question like that and then wait for the reply, you could have been out flying it already.

U Can Do 3D
 

Well I'll tell you Minnflyer,

If I was retired or independantly wealthy, you may be right in your assumption. Unfortunately, I don't have as much time to build as I would like. Like the majority of us, I do have to work for a living. I posted this question last night in the hopes that I would get at least one or two replies before I got to that point. Today, I got the cowl mounting blocks and the bracket that I fabricated yesterday for the quick fueler valve glued on to the firewall along with installing remote glow driver. Just got the cowl mounted before I had to quit and go to work.

Things are not always what they seem. Happy flying though.

Jeff

U Can Do 3D
 

Well I apologize Jeff. Yours is not a unique situation.

So often I see questions asked that really don't need asking that sometimes I speak when I shouldn't.

On the other hand, many times someone just needs a little reality check, and they are usually grateful for it.

I certainly didn't mean any disrespect by my comments, and I'm sorry if I offended you.

U Can Do 3D Balance
 

Loopnspin, Minnflyer is correct in saying every plane is (even of the same model) is different. I keep that in mind when I build a plane from a kit. I will build the tail heavy if I'm using a light engine (use epoxy, beef up the structure, use heavier hardware etc. or vice versa In your case you don't have that luxury.
Here is a way to get a rough balance of your plane without installing the battery. Try putting all the other components together as far as you can. If you have the option to move the servo tray around much leave that out. Install the pushrods leaving a little long, then put the wing on, set on a balance stand, and then set the servos and battery on the out side of the plane, use double stick tape to keep them from falling of. Keep in mind the servos can only get moved around so much.
Take note were components are, then permanently install inside and recheck the balance. It should be close. I hate to add lead to a plane if I can add it in some other form, to improve performance, or strength.
There are many ways to adjust a planes balance, wheels come in different weights and sizes, the low bounce wheels can be pretty heavy, while the foam ones are pretty light. Spinners can have different weights. Battery size can vary alot too.
Give it a try if you haven't installed the stuff yet.
Good luck

U Can Do 3D
 

Hey Mike (aka Minnflyer).

No apology necessary. The one bad thing about electronic correspondence is that it is impossible to read body language when conversing with another person. Obviously, I very much misjudged the good intention of your first reply to my thread. I just got the wrong impression from it.

I think it is best to put this thing behind us and do what all of us enjoy most- talking about this great hobby and helping one another.

And mvasapoli, thanks very much for your input. All your ideas are very sound. Unfortunately, only some of them will work with this particular plane because both elevator servos and the single rudder servo are mounted at the rear sides of the fuselage. Trust me on this though, one way or the other, I will get this sucker properly balanced.

Thanks again to everyone who responded to my question.

Jeff

U Can Do 3D
 

Works for me!

BTW, you're going to love that thing. I was talking to Marc (RCAdmin) about it at Toledo. He did the RCU mag review on it, and said it was a winner and really does make 3-D flying easier.

I just may have to get my hands on one (if I ever get all of my other projects finished!).

Update On U Can Do landing gear
 

*Please also pass this on to anyone you know building this plane.

Attention to everyone waiting for their GP U Can Do 3D or are in the process of assembling it.

With all the discussion I have read about the landing gear failing on this plane, I decided to have a look for myself before I installed the canopy. So I cut out a section of the cockpit floor just above where the landing gear foundation sits. And boy howdy am I glad I did. What I found was very little epoxy (if that is truly what was used) In my opinion, this would have no doubt failed over a short period of time even with the smoothest of landings.

So, what I did was use a #11 Exacto knife and cut out what little glue was there so I had a nice flat surface. Then I inserted an
8-32 bolt a short ways into the blind nuts (which were also unglued) and popped them both out. I then cut a 1/8" piece of lite ply to overlay on the hardwood block and used 30 minute epoxy to glue it in place and then added some triangle stock on top of that to really reinforce it. After the glue dried, I re-drilled the holes for the blind nuts (using the landing gear holes as a template) and reinstalled them. As a last measure, I drilled one additional hole in between the two 8-32 bolts and screwed in one #8 x 1" sheet metal screw.

If you are careful about cutting out the hatch in the canopy floor, it should be very easy to to reinsert it.

*Be sure to put a little vaseline or something similar in the blind nuts to be sure epoxy doesn't get into them too.