3,227 total views, 1 views today
The Skybird arrived in a box measuring 46 x 8 x 4 and it leaves in a box measuring 60 x 8 x 16 go figure.
Total Build Time 105 Hrs
- Fin and Rudder 29 Grams
- Stab and Elevator 50 Grams
- Left Wing c/w joiner 407 Grams
- Right Wing c/w joiner 403 Grams
- Fuselage 445 Grams
- Wing Rods and Incidence Pin 233 Grams
It’s a rather breezy cool day here, and I wasn’t sure I wanted to take the Skybird out, here it is though a mere skeleton of what it will look like when it gets covered.
Back into a box, not quite there yet however the box is being done up.. It’s inevitable this bird will be headed home soon, and I can’t wait to see what colors it gets.
Here is a close up picture of the wing root filler on the fuse. I have added some fillet spackle around the edge, and tapered it in nicely. Gotta be sleek for best performance and looks
Close up of the nose, it may need to be cut back a bit more to suit the spinner and adapter. Some additional sanding also needed in this area.
I cut two new ply scarf pieces for the rudder, I have also added some relief to set the pieces in , so the rudder is flat after
a little weight to hold things together while the glue sets
Something got loose in the box during shipment and damaged the trailing edge on both sides of the elevator
I cut some notches and have set in a couple pieces of scrap balsa
A lot of balsa dust and I reckon there’s more where that came from.
For comparison I placed a Sagitta 900 fuse up against the Skybird
Everything comes together here in the tail. Control rods cross and a tube for a 72 MHZ antenna.
3/32 alignment pin in place , they are intended as a friction fit in the tip panels, and then fit into a corresponding brass sleeve in the main panel
As I have done with my Elio, I’m using a ferrule and then filing the washer part off later
To the scales
Tip panels on the scales, 205 Grams, oh oh, why didn’t they come out at 100 each??
Is there someone who would like to figure out the difference in yaw moment?
Well actually resolution on this meat scale is 5 grams. I later set them on another scale which resolves to 1 gram and it turns out one panel was 101 and the other 104, I missed some saw dust somewhere
Please introduce me to the glider guider that will notice the difference in flight.
Tip block in place , lot of sanding left
Right main panel, I’ve done a lot of sanding on all 4 panels at this point. Still some more to go yet, i like to get things lightened up
Tip in good shape
another tip shot
Matched pair , big set of wings . The panels fit together nicely.
It’s a beautiful morning here, just above freezing and a shimmer of frost on the chicken coop, light clouds in the sky.
Lower forward fuselage ply is glued on , taped to hold in position and some weights on top.
At this point the forward portion of the fuselage was stiff enough that alignment was not an issue.
i had to add a couple ledges to set the middle cover on. to keep it from falling in
I added an alignment ply sheet on the underside of the canopy, you can’t see it in the picture but it keeps the canopy aligned with the fuse, left /right
Center cover with forward pin, also tube for antenna can be seen in rear fuse bay
Back to the wings, a lot of small jobs left, one of them being to add the ply root ribs, it’s nice to be able to do this with the wings drawn tight to the fuselage
Right wing root rib secured in place
Right wing main panel LE sheeting finally in place
A piece of filler sheet is added on the right wing
The Leading Edge seems to be missing a bit of material, so I had to build it up with a piece of 1/8 strip
Leading edge taking shape, gonna be nice
Wing root saddles in place both sides of fuse
I’ve added a couple supports for a servo tray here, in case this option is deemed most suitable later
control rod support tubes
Fuse tail block in place , it needed to be tapered to fit.
Ply is added to the stab, top and bottom .
Forward stab mount pillar, a 4-40 screw will pass thru here and pick up the blind nut on top side of stab
Stab top side ply and 4-40 blind nuts
rear stab mount pillar
adding the top rear decking. I jigged the fuse along a straight line under the former centers. and secured on both sides prior to gluing and clamping the sheet
Formers F5and F6
Wing roots, I have added an extra hole for the eye pass thru to secure the wings and a slot for the servo wire coming from the spoiler.
Stab mount being added
Top deck sheeting, once this piece is in place, it will pull all things together..
I added a notch on the underside so that it sat correctly on the stab mount at the rear
I’m on my way back!
Before I move on, I recently stuck the tips on to the main panels with the joiners flipped over. The wing actually doesn’t look that bad “gullwing”, it would be kinda neat to see how it flew, or?
I don’t want to be the 1st guy sending it up the line though!
I had previously laminated the 1/64 ply doublers on the insides of the fuse sides, as well as the the 1/32 forward balsa sides…
I have to add some gussets for F1 and Motor Mount M1. By adding these now I have something to press the formers up against when the fuselage sides are together
Formers F3 and F4 in place, I like to place these onto one side 1st and make sure they’re square and aligned properly.
Spruce rails in place on both sides and F2 squared up and glued in.
Servo tray support in place, I have also marked the bay between F2 and F3 in case it makes more sense to mount the servos there.
New former F1 and M1 , the sniffer is shaping up rather nicely.
I used the rear part of the nose block to give me the shape and filler needed around the motor mount.
Today is not a big day for building, it was time to figure some things out.
As this bird is gonna be electric there are some concerns about motor placement and battery placement.
There’s lots of room in the fuse but no need to add extra weight especially in the tail..
Also, I am gonna re visit the polyhedral break angle and this business about raising the tip 6 3/4 inch above the flat surface at rib #27..
This is a really big plane, in both dimensions with the huge chord
The tail, lots of green tap to hold things together
Back to the wing tip, from online info and the slightly misleading dimension leader on the drawing it was determined that the wing tip is to be raised 6 3/4 ” above the building surface and the braces where to be glued against the spars with the tip in this position.
As I was building joiners and spar boxes, I needed an angle .
What better way to get that then to measure the angle of the 1/16 ” brace.
I built the joiners and placed them, uuuuh ooooh!! I hate it when this happens
That turned out to provide tips that where less then 6 3/4 inch above the work surface..
Oh well I made another set and started by making 1 joiner that worked ( 1 1’8″ ply only) and that got me close to 6 3/4 inch at rib # 27.
I proceeded to make both joiners after with this pattern
It continued to bug me why this was wrong , and I believe what it is is that the angle on the braces is incorrect, maybe they are from one of the other planes in the bird series..
Not a big deal if you set the wing up and then glue the braces to the spars. I’m not sure but I reckon that the edges would also have to be sanded on the braces so they don’t fall below or above the top or bottom surfaces..
I made a sketch today
I set the brace flush to the lower edge of my build board using a 4 ft level. I extended a line to represent the lower edge of the tip panel from the brace..
I measure out the length of the tip panel 29 7/16 ” to rib #27, at that point a line drawn down bisecting the lower edge of the board at 90 Degrees measures 6 1/4 ” .
Not 6 3/4
All good info, If you where there.
For all the weary and confused unless your building a set of joiners and removable tips, set the tips 6 3/4 above the board and be prepared to sand the edges of the joiners..
That’s all folks . LOL
adding the 1/16 ply cap to the tip joint
Left main panel ply cap
Leading edge sheeting in place..
Nov 01 2013
Rear alignment tube and spoiler spar have been added
Left tip panel trailing edge sheeting pinned down.
Right tip panel
Right tip panel leading edge sheeting in place. Gonna be a nice set of wings
Notice the lead, they are 4 lb blocks, what a great investment.
I am supposed to met them down into weights for my wife’s sock knitting machine. I’m gonna get some more the next time I’m in town. Lead is 1$ a lb a good investment!
Seems like I’ve been spending days working on the joiner box and joiners. Turns out the spars are two different widths 1/4 ” and 3/8″ on the main spar. Rather then have a stress concentration, I’ve added a bit of taper into the box on the tip panels..
It amounts to some wedges on the LE side of the spar. Also the spars pitch changes as you move towards the tip so I had to cobble together something there as well in order that the joiner would fit tight.
The 1st piece of what amounts to 4 parts for the joiner, 3 x 1/8 and a piece of 1/16 ply.
Here is one of the joiners laminated together and set aside for curing
There’s also a bonus gift for you Bill, a extra set of joiners, one set will get the 6 3/4 ” dimension as called out on the plans and the other is less..
Well a little more then 6 3/4″, once gravity gets hold of this it should settle in nicely..
Finishing up the sheeting on the bottom of the main wing panel. I have added some fillets here to take away some of the square look when the covering goes on.
I hope you like it?
A coming together main meets tip. Plenty of preliminary work here so that both panels line up nicely when the joiner is added
6 3/4 inch at the final rib, looking good starting to take shape
Tip panel root rib. I have tacked in in with epoxy, it will get the reinforcements it needs later , the key is that it’s square to the spar,.
I really like how this is coming together, and did I tell ya it’s gonna be a big plane, and the inner panels are robust with those two wing rod tubes
Left main wing panel spar construction as well as addition of shear webs, a three step process that makes a very strong spar
Reinforcement gusset is in place at the polyhedral break, later I’ll add a ferrule and pin to tie the outer panel to the inner panel
fuselage area at wing , plenty of room behind wing rods for battery
Hacker Motor with gearbox. Fit will not be a problem, I’ll fabricate a firewall and consider spinner size to make a smooth transition to the nose are
Tail group, gonna rework this a bit so both tail and stab can be bolted on for easier transport.
Rear spar and spar fillers in place. I still need to cut the groove behind this spar for the doubled up shear webs
I pressed the fuse halves together onto three of the formers. There’s lots of room here for the battery and ESC, will have to do some checking with the motor on the nose to see where the CG lies though
Back to the wings. The wings are laid up with all ribs glued to the spars and only later are provisions made for the 5 plywood shear webs that are glued to either side and in between the spars.
The wing should be firmly attached to the board, especially watch the leading edge so the wing form is kept, and then the ribs can be cut to allow the ply shear webs to pass thru
The forward wing tube should be secured before this slot is cut, it helps to stabilize the ribs.
All glued up , this process will be repeated two more times to secure the middle shear web and the doubled up rear one.
Cutting the middle shear web slot, the rear wing tube is in place to secure the ribs.
Underside of wing main panel.
All ribs except the end ribs are glued and pinned to lower leading edge sheeting, I’ll do the end ribs with a square later
Fuselage forward section, under weights the ply is glued to the outer balsa sheathing
Forward wing rod tube tacked into place, afterwards I’ll be able to cut ribs for the plywood shear webbing
Finished forward fuselage , both sides
Forward fuse meets rear fuse, glued and held straight on bottom side against a 4 ‘ level
Both tip panels, one panel is on the board to have the rib filler pieces added at the trailing edge
Wing panel upper spar.
Rib #1 on left main panel and glued in place
Left main panel, at polyhedral break, considerable work has also been done fabricating ply cap ribs at join, and ply sides for joiner box
wing rod tubes left main panel
Right wing panel, ribs in place other then #1. Lower rear spar extends thru to end of spoiler bay like the upper rear spar.
I had to cut some 1/8 x 1/4 balsa to fit between the ribs as reinforcement between the rear trailing edges.
The instructions refer to these being pre cut but I couldn’t find them
I cut out a couple windows of 1/16″ Ply to reinforce rib #9 where the spoiler servo gets mounted.
I will add a piece of 1/8 ply to the back side, a little block on either side, for the screws so they have a little meat to grab on to
This picture will give a better idea where the servo will be , directly under the spoiler so it can be removed.
Rib # 9 in place
Left wing panel, I’ve cut most of the 3/8 balsa shear webs that fit between the spars
I have the main panel plans on the board,
I’ve ripped the spars to .375″ wide, others have had problems with getting the ply shear webs in between the spars. I reckon I cut .025″ of 3 of the main spars, .05″ is almost the full thickness of the 1/16″ ply shear web that has to be placed between the spars.
The spoilers are a build option for this kit, so some ribs need to be modded.
I’ve also notched 4 of the ribs to accept the longer sub spar that passes in front of the spoiler opening.
I will also notch these ribs in the bottom as well to accept this longer spar.
There are no notches for the rear 1/8 x 1/4 Spoiler spar, so I will cut these in prior to placing these ribs.
Holes will also be cut into all ribs for feeding thru the spoiler wire.
One spar was actually narrower then the 3/8 inch, however shouldn’t be a problem as I just noted the straighter of the edges and will use that for the top portion of the wing spar build up..
I’ve placed a lower leading edge sheet and a spar on the plan and will use a straight edge to pin both pieces to the board straight. I fell more comfortable with this method then using the line on the plans.
Right wing panel, I had removed it from board and set back , to add the 1/16″ shear webs. There’s 72 1/16 shear webs supplied with the kit and only about 4 of them can be used for each tip panel. The spacing on the rest of the ribs is wider, and for those that are narrower towards the inboard end of the tip the shear webs are not high enough..
A sheet of 1/16 x 3 x 24″ balsa was sufficient for the rest of the shear webs on the tip panels
Ribs glued in place on right tip panel
This picture should show how the spar increases in height , before tapering to the tip
Left tip panel
Both panels of the board, the leading edge is up next. It will require some tapering and cutting to fit that way I save on sanding later
Left wing tip bottom leading and trailing edge sheet and lower spar with ribs
Right wing tip
I had to re shape joint edge where the inboard rear sheet W6 meets the outboard sheet W7 to suit the plans and the ribs.
Also, verified all ribs fit onto spars top and bottom
I’m getting a Skybench Skybird Sailplane sent to me..
132″ WS RES Rudder , elevator , spoilers sailplane
Custom build as well, there will be a motor added, as well as the wings will be done with joiners, at the dihedral break
The wings are 5 ‘ plus in length so that will make the whole setup a little more portable..
I’ll try and post some pictures here as I do the Build
Skybird arrived Oct 15 2013
all intact a lot of lumber for this classic
Rib set , left and right