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David's Standard Ballerina

First scratch build for many years

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Peter Miller17/03/2016 14:42:06
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10331 forum posts
1231 photos
10 articles

When I have this problem I cast the lead in a suitably shaped square hole in a block of wood and then insert it, either under the engine if there is room or I cut a similar shaped recess in the sheet under the cowl.

It is going to take a largish lump of lead to move the CG forward that far forward. I expect you could allow the CG to be a little further back, not not much.

Martyn K17/03/2016 16:36:59
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5006 forum posts
3669 photos

That colour scheme looks fantastic. Very nice indeed

M

Chris Barlow17/03/2016 17:28:58
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1858 forum posts
1266 photos

Where is your rx battery David? Can you get it in the nose under/over the tank?

David Hayward.17/03/2016 17:39:28
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170 forum posts
82 photos

Hi Chris, yes I have been thinking about putting another window in F2 at the bottom so I can slip the battery in under the tank, good suggestion. I also don't have the spinner or prop on yet so I may not have to add too much weight once I have done all this.

David Hayward.17/03/2016 17:46:41
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170 forum posts
82 photos

Actually not much room under the existing window and of course the wing dowel locates in F2 so need to be careful of that.

Chris Barlow17/03/2016 18:00:42
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1858 forum posts
1266 photos

You could remove the tank to install the battery sandwiched between layers of foam, then refit the tank over the battery?

With the battery in with the tank and a nice ali spinner I don't think it'll be too far off.

Lucas Hofman17/03/2016 20:25:38
600 forum posts
316 photos

I have always used glue-on weights, as used to balance Alloy wheels for cars. You get these in 5 and 10 gram units. They come on a foam pad with a really good glue. Clean, simple, adjustable at the field and reasonably cheap. I think I paid £5 for 250 grams or so.

I often tape them to the outside of the cowl (with masking tape) when trying out how much is needed. Trim for hands off while flying upright, roll to inverted and see how much "down" is needed. Adjust the weights until satisfied.

When at home glue all to the inside of the cowl and you are good.

Lucas

Bob Cotsford17/03/2016 22:38:14
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8070 forum posts
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Posted by Chris Barlow on 17/03/2016 18:00:42:

You could remove the tank to install the battery sandwiched between layers of foam, then refit the tank over the battery?

With the battery in with the tank and a nice ali spinner I don't think it'll be too far off.

That would be my first choice too. After all, how often do you need to access a battery - once a year for a check?

Rosco18/03/2016 18:56:29
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448 forum posts
386 photos
Add another one to the 'like' list for the colour scheme.

I really am getting itchy fingers now. I'm still a few weeks away from getting back to my build yet!

all these Ballerina builds are looking good, but I have yo admit, I do have a couple of favourites!

Rosco

David Hayward.18/03/2016 22:03:28
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170 forum posts
82 photos

Right, so battery pack now installed in front of F2 under fuel tank, prop an spinner fitted and C of G now about right; I think I need to devise a more a curate means of balancing models rather than just my finger tips. Hopefully take some pictures tomorrow of a completed Ballerina......

Peter Miller19/03/2016 08:33:49
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10331 forum posts
1231 photos
10 articles

I take some Solartrim and stick about 3 layers together. Then I cut out small arrows and stick them to the top of the wing(for low wing models) at the CG location.

Assemble model, turn upside down and the arrows can be felt with your finger tips. Simples.

If yu want to be really fancy get a block of wood, Buy a packet of push on pencil erasers Drill two holes for pencils. Insert pencils with erasors on top. Use that to balance model

David Hayward.19/03/2016 12:56:09
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170 forum posts
82 photos

Thanks Peter, I feel a bit dumb, can't believe how much easier it is to balance the model up side down, obvious now.

Anyway, a couple of images of the completed Ballerina...

p1020236.jpg

p1020263.jpg

So this is Annabelle who will be piloting my Ballerina and with regard to the slightly rearward C of G issue, once I moved the battery in front of F2 and kept Annabelle off the burgers for a couple of days, were all good.

I have a few more images which I will put in the Completed Ballerina thread.

Peter Miller19/03/2016 13:58:50
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10331 forum posts
1231 photos
10 articles

Nice. I like Annabel.

Trust me, over the years I and a few other older members of our club have often said. Why the heck didn't we think of that!!!

One of best examples.. When I was editing "How I did That" in AMI someone sent in a tip. When shaping a trailing edge from balsa mark the width on the sheet, shape to the line and then cut it off..

Four of us, all with at least 5o years of scratch building had never thought of doing it that way and it is SO obvious when you think about it. We had cut the width and then shaped it with nothing to hold onto.

McG 696919/03/2016 18:23:09
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2732 forum posts
1026 photos

Hello David,

Your Ballerina looks really great and frankly innovative compared to the Mass. Not really surprised as your build was up to the same kind of very tidy standards. Congrats.

One question though: are you really sure that Annabelle has the required age to get a PPL licence & to get soloed to require the PIC status? Really wondering... wink

But maybe then I'm out of awareness of some special 'higher end granting'... One could easily connive with those pair of eyes, ain't it? angel

Hakuna matata

Chris

BRU - BE / CTR Look Control

David Hayward.19/03/2016 18:43:55
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170 forum posts
82 photos

Thank you Chris.

On the question of age for a PPL, well, trying to keep that under the radar so to speak, but what she lacks in experience she makes up for with cuteness.

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