Ballerina - Material list

[kc]

After a quick look at the plan this evening I have drawn up my estimate of the main materials needed. Obviously this is unproven and just an estimate. You should check for yourself before placing an order for balsa!

Balsa all 36 inch long
1/16 by 3   1 sheet  webbing.

1/16 by 4    5 sheets wing sheeting + fus underside

3/32 by 4 3 sheets fus sides & turtle deck
3/32 by 3 3 sheets wing ribs
1/8 by 4 2 sheets formers, fus under & Leading edge
1/4 by 4 2 sheets fin tailplane rudder & aileron spar
1/2 by 4 half sheet (18 inch) cowl
1/4 sq hard 6 strips main spar & aileron spar
3/8 by 1/8 2 strips Trailing edge stock
1/2 triangular 1 strip

Ply and spruce.
1/8 sq spruce 6 pcs 36 inch
1/32 birch ply 18 inch by 12
1/8 birch ply 8 inch by 10 inch
1/4 birch piece 3.5 by 4.5 inch
1/8 Liteply piece 9 inch by 12 inch
1/4 dia dowel piece 1.5 inch

 

Edited By kc on 27/11/2015 19:48:14

[Biggles' Elder Brother - Moderator]

You're "ancipating the sacrament" a bit there aren't you KC?

BEB

[kc]

kc's notes.

1. This is for the standard IC version as shown in RCME without modifications

2. The 1/4 birch ply could be produced from laminating 2 layers of 1/8 birch ply. If you order a 12 inch square of 1/8 it should be enough for this as well.

3. Anyone building the model for electric will probably need an extra piece of 1/8 Liteply ( perhaps 7inch by 3.5inch ) for a battery tray. So if you order a 12inch square that should be enough.

4. Lots of the ply parts can be made from smaller pieces - you dont necessarily need it all in one piece.

5. VERY IMPORTANT. Clever use of material is needed to get the model out of the minimum material shown.. For example the large pieces 1/16 for wing sheeting need to be cut or at least reserved first. The excess 9 inches on each piece are then available for the fuselage underside sheeting. If you just make the fuselage first and cut up a whole sheet to sheet the fuselage then there won't be enough large sheets left for the long lengths needed for leading edge sheeting. Same with 1/4 Tailplane parts - plan the main parts first and use the offcuts for other parts.

6. If you live a long way from a model shop or order by post then order an extra sheet of each size in case you make a mistake. Or in case I underestimated!

[kc]

BEB - I am assuming lots of people will build this model anyway regardless of which model is selected!   And anyway the Oodalally, Harlequin, Dragon Dancer2 and Werewulf use  pretty similar materials.   The first three would need the addition of aileron TE stock but I think they could be built with the same list of balsa & ply.

 

 

Edited By kc on 27/11/2015 20:05:49

[Biggles' Elder Brother - Moderator]

Only pulling your leg KC! I was indeed hoping that you would do such a list. Very helpful and thanks.

BEB

[Peter Miller]

Add

1 length 16 SWG wire unless you are using two servos for rhe ailerons

2 90 degree bellcranks unless ditto.

1 length 8 SWG piano wire.

[Paul Marsh]

I've got about 20 % of the Balsa wood for it, and all the ply. So an order to SLEC or Balsa Cabin is imminent.

[Whatgoesup....]

Thanks guys - this could be very useful info come Sunday

[kc]

Hardware List

8SWG ( 4mm) Piano wire 1
16 SWG (1.6mm ) Piano wire 1
Saddle clamps 2
'Snakes' 36inch Heavy duty ribbed 2
Snake ends M2 studding 4
M2 threaded rods 3
Bellcrank ( if used) 2
Clevis 7
Horns 4
Engine mount
Captive nuts to suit mount ( M3? ) 4
Captive nuts for wing bolts 2 ( see note)
3 inch Wheels 2
Tailwheel if required. ( or use tailskid as plan )
8SWG wheel collets either 2 or 4 if you don't solder
throttle cable of your choice
Servo mount ( sideways type SLEC or RadioActive ) if required for single aileron servo

fuel tank

 

Notes

1. Captive nuts need to suit wing bolts. SLEC sell 2 BA wing bolts but not 2BA captive nuts. On the other hand they sell M6 captive nuts but not spare M6 wingbolts! They sell a set of M5 or M6 wingbolts and captive nuts though.  Spare M5 wingbolts seem available.

2. The hardware list suits Peter's single aileron servo style. If you want to use 2 aileron servos out on the wings you may not need the all the same hardware. However you will need to make holes in the ribs big enough to take servo wires with plugs. Do this at rib cutting out stage! You will probably want to fit paper tubes for the servo leads whilst constructing wing.

3. This is just my idea of what hardware might be needed to make the i.c. plane as plan. SLEC brand items are my normal choice & they are usually available at local model shops or direct from SLEC. Other people might use different hardware.

 

Edited By kc on 28/11/2015 15:40:27

Edited By kc on 28/11/2015 15:44:48

Edited By kc on 28/11/2015 15:52:22

[john stones 1 - Moderator]

Just the covering to list now K.C

John

[kc]

A 5 metre roll of film from Hobbyking should do! plus another colour for trim. Beware the postage cost though.

[Peter Miller]

Model Fixings do all the captive nuts and nylon bolts that you can dream of.

I like the ones with the knurled heads so you can screw them in most of the way with your fingers.

[Craig Thomas]

Just a quick question, with this material list, I assume it is thought that you will make you own webbing strips with a strip cutter? Just want to make sure I'm right in my thoughts so I know to buy a cutter.

[Peter Miller]

The webs are made from 1/16" sheet, the grain runs vertically because it is meant to hold the spars apart and so the webs are in compression.

Because the wing is parallel chord you can cut one to width and use that to cut all the others.

I cut the sheet to the right width before cutting the webs. The excess can be cut for the rib capstrips

Add one sheet of 1/16" X 3" X 36" to the materials list for the webs

Edited By Peter Miller on 29/11/2015 08:32:47

[kc]

Craig, if you were referring to the capstrips ( 1/4 inch strips along the rib tops ) rather than webbing then the answer is a strip cutter is handy but not essential. Just a ruler and scalpel will do. No need for very accurate width. But essential to use the same thickness sheet throughout. ( 1/16th sheet varies a lot )

Additional Hardware items

( I overlooked the elevator joiner.)

14 SWG ( 2mm) piano wire about 6 inches required.

Note

The wing dowel needs to be hardwood -birch, ramin etc ( I just noticed that balsa dowel is sold - you don't want that! )

[Clive Hall]

May I chip in here with a comment about spar webs? The prime function of webs is to prevent the upper and lower spar booms from shuffling relatively in a spanwise direction. Without a web the wing under a lift load can bend, moving the upper beam outwards relative to the bottom one and cracking the joins to the ribs as they try to assume a different angle to the boom, sharper on the top, wider on the bottom, and most evident towards the wing tips. Therefore to resist this movement the webs are in shear rather than compression.

The ideal material for wooden wings is plywood with the grains set at 45° to the spar booms, though the standard practice of vertical grain sheet is fully adequate for models. Some full size aircraft do not use sheet webs but fabricated box section joiners between the booms from the bottom of one rib and the top of the next one: this was done on the Boeing B-17 along the whole wing.

Another point concerning sheet webs is whether they should be fitted to the front or rear of the spar booms. The only reference I can find here relates to a decision in August 1936 to make Spitfire wings torsionally stiffer. This was done by moving the webs from the front face of the spar booms to the rear face.

[kc]

Peter said earlier that an extra sheet would be needed for webbing. I think the one sheet of 3 inch by 1/16 -first item in my list - should be just about enough. I measured that each web is 1 3/8 deep so 22 bays altogether 1.375 by 22 equals 30.25. so should just come out of that one sheet with careful cutting.

Buying extra in case of errors would be a good idea though.

[Paul Marsh]

Had enough wood to cut all the ribs out, all the formers and the rudder only.

Still have a few sheets of 1/16 and a couple each of 3/16 and 3/32.

[Peter Miller]

Posted by Paul Marsh on 29/11/2015 22:19:36:

Had enough wood to cut all the ribs out, all the formers and the rudder only.

Still have a few sheets of 1/16 and a couple each of 3/16 and 3/32.

Where are you planning to use 3/16" sheet?

[Craig Thomas]

Where's the best place to buy the balsa from?
My local model shop is 15 miles away and only has a very limited selection. Kind of pricey too.

[john stones 1 - Moderator]

Slec balsa cabin good idea to buy extra for your future needs Craig and save on postage

John

[kc]

Perhaps Inwoods are nearer?

Edited By kc on 30/11/2015 18:13:50

[Peter Miller]

SLEC, Don't forget to tell them what grades i.e. hard, medium, soft that you want. You want one 3/32" sheet as soft so yu can roll it round the turtle deck and you want medium for the ribs and medium to hard for the fuselage sides.

Spars quote "Rock hard"

[Gary Manuel]

Good advice there Peter,

Just the sort of thing us inexperienced builders need. Wood selection is one area where I struggle.

[Craig Thomas]

Can anyone please help me out. I'm putting my order in for wood. Ordering from slec. On the material list is says 1/4 birch piece. Is that birch ply or solid birch? Am unable to find either on slec.