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David's Standard Ballerina

First scratch build for many years

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Peter Miller08/02/2016 13:46:09
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11368 forum posts
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The servo mounts make life so easy. Just screw them to the ply plate, slider the servo lugs into the slot, screw the caps on, job done.

You may have to thin the servo mounting lugs down a bit but that is no problem.

Tips looking good.

kc08/02/2016 13:56:45
6646 forum posts
173 photos

I discovered just this morning that items made by RadioActive Manufacturing are available by phoning them direct. Website has catalogue only no online sales so you have to phone. Item CA 190 may be the servo mount you want.

David Hayward.08/02/2016 14:05:09
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176 forum posts
97 photos

Hi KC, actually ordered them from RCWorld: -

Should arrive today, fingers crossed.

Edited By David Hayward. on 08/02/2016 14:06:23

David Hayward.10/02/2016 12:27:54
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Now added the tip outer strips. Wasn't sure if these also went under the leading edge sheeting however have also fitted here and it seems to make the sheeting fitting a little easier. I have sanded down the strip under the sheeting more so it will match the height of the rest of the edge strip; if that makes sense?

20160209_194436.jpg

My servo mount brackets duly arrived and are now fitted with an addition 1/8th plywood plate under to give more depth for the fixing screws plus it gives my linkage some necessary clearance from the base . I used a drilled out 2BA nut to bond the piano wire linkages together and connected to a rx for testing of operation so far; all good, full movement, no binding of the linkage or stressing of the servo.

20160209_202001.jpg

Peter Miller10/02/2016 12:53:38
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11368 forum posts
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Actually the strips were not meant to go undr the sheet but that was just the lazy way that I did it.

I do like your use of the nut for the connection. Takes up a little more space but it does allow the solder to flow better than in the 8 SWG tube that I use.

kc10/02/2016 13:20:00
6646 forum posts
173 photos

David, could you give a fuller explanation of how you soldered it all up? . There may be many others who have not quite reached this stage yet who might be glad of some tips.

I assume you found some way to fix both ailerons firmly at neutral before soldering.......

Peter Miller10/02/2016 13:30:18
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11368 forum posts
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10 articles

Well I don't know aboutDavid but I use a couple of paper clips, the big bulldog clips.

Nthingmoves when clamped with them

David Hayward.10/02/2016 14:01:42
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176 forum posts
97 photos

Well the piano wires from the servo position are connected to the bell cranks on either wing, which you can see in some previous photo's. The bell crank ply mounting plates now have balsa triangular section to strengthen the bond to the wing ribs.

The two piano wires from each bell crank obviously need to cross over slightly in the centre of the wing (servo position) with the nut or appropriate size tube slid over them. At this point I centred the bell cranks and held in position with pins pushed into the balsa triangle section adjacent to the bell cranks, two for each. The link wire to the servo is then added, passing through the nut, with the servo attached but not fixed in position yet.

I then soldered the joint with a heavy duty soldering iron (not sure of the wattage, it was my fathers, so its pretty old) having previously cleaned the wire and nut to ensure a good solder joint; fairly tight space but managed not to melt anything apart from the solder.

Next I connected the servo to a rx and tested operation (release the pins holding the bell crank first) holding in a position where movement is free etc; mark and fix the servo; job done.

Martyn K10/02/2016 15:41:20
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5088 forum posts
3681 photos

Very neat building indeed David

kc10/02/2016 17:02:24
6646 forum posts
173 photos

Thanks for the explanation David - it should be useful to lots of other builders.

David Hayward.15/02/2016 20:24:09
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176 forum posts
97 photos

I am in the process of making the final linkage connection to the ailerons and I am wondering if I should build in some mechanical differential by offsetting the control horns. I have used a central servo and of course will not be able to do this via the tx; be grateful to you get some suggestions on this.

Peter Miller15/02/2016 21:03:06
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11368 forum posts
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Well I didn't and I am happy with the way it flies.

If you are a pecision aerobatic pilot you will know what you like but Ballerina is not meant to be such and aircraft.

I just throw mine all voer the sky. Usualy the only time she is flying straight and level is when she is inverted.

David Hayward.15/02/2016 21:12:58
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176 forum posts
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Thanks Peter, I'm sure that will be good enough for me then and I could always add a little later if I felt like experimenting.

David Hayward.17/02/2016 09:28:40
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176 forum posts
97 photos

Finished building the tips, added sheeting to tips and underside of wing, also added leading edge cap strip...

20160213_115321[1].jpg

Next I set about hinging the ailerons and I notice most builds I have looked at are using flat hinges but I had already decided to use pin hinges (do they know something I don't?). What attracted me was the apparent ease of installation, just drill a hole. So used the Robart hing jig to drill holes in the ailerons for the pin hinges and then made up three small pieces of piano wire to pass through these hole to mark position for the hinges on the wing itself; hopefully this picture will make that clearer...

20160213_160750[1].jpg

Ailerons then dry fitted so I could finish link from bell crank to aileron horn. I have glued a 1/16 medium balsa filler piece on top of the ply horn mount to bring the level of the horn flush with the bottom of the aileron.

Having formed a 'z' bend in the wire to locate in the bell crank I then formed a second 'z' bend to lift the wire out of the wing so I can keep the slot in the 1/16 sheet fairly short and close to the bell crank to enable removing/replacing the wire link if necessary...

20160216_200529[1].jpg

Using a temporary card template I marked out the potion of the slot...

20160216_200902[1].jpg

Then used this to mark the 1/16 sheet before fitting...

20160217_074205[1].jpg

For the keen eyed I will fit retainers to the clevis's on final assembly, this is just for me to test the operation of the aileron linkage before moving on.

Peter Miller17/02/2016 11:44:17
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11368 forum posts
1342 photos
10 articles

Looking good.

Nothing wrong with pin hinges. I just tend to be lazy! but, thinkingaboutit, I might just use them on the current model

john stones 117/02/2016 16:40:40
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11648 forum posts
1517 photos

Yep nothing wrong with Robarts, the flat ones need less accuracy is reason I fit them, I don't bother with keepers on steel clevises myself you can't get em off when you want to

John

David Hayward.17/02/2016 17:01:02
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176 forum posts
97 photos

That made me chuckle John, I know what you mean; sods law says you struggle to get the damn thing undone when you want to but it will happily disengage during flight all on its own.

Peter Miller17/02/2016 18:14:56
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11368 forum posts
1342 photos
10 articles

I never use keepers on metal clevises. I never use plastic clevises.

Having said that I do use keepers on American clevises as they seem to be made from much less springy metal

Bob Cotsford17/02/2016 19:54:57
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8749 forum posts
489 photos

I use keepers on metal clevises but then I don't use Sullivan metal clevises, I've had too many where the pins separate from the fork.

Geoff S17/02/2016 20:52:41
3774 forum posts
36 photos

I don't use any US fitting with threads. I stick to known metric threads then there's less chance of errors with ill fitting parts.

Geoff

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