Phil's F-86 Sabre build thread

[Phil Cooke]

Lifting the wing back off once the caps had dried revealed the improved wing seat - still a little fragile at the extreme front and rear as the 1/16" balsa is left somewhat cantilevered and is in need of some little internal fillet blocks to make it more robust.

Sanded back to the fus profile leaving some stock for the fillets at the T/E

A good match! Just need to block in at the front and rear when the little fillets and L/E extensions are done. Will have to work on the fillets next as they are very fragile in their current state when the wing is off.

Edited By Phil Cooke on 24/05/2020 20:10:36

[Phil Cooke]

Front wing blends done today, cut from an oversize section of aileron stock.  These took way too long when you look at the finished article, in truth they are complex little bleeders and the sanding of them (particularly the top side up against the re-entrant fuselge section) is tricky without damaging he surrounding parts. I was very glad I'd glassed my wings in advance.

Lined with 1/32" ply at the rear - which also hampered the final shaping exercise.

A little filler needed to achieve the smooth blend.

Job done, now onto the Trailing Edge fillets.

Edited By Phil Cooke on 25/05/2020 20:47:38

[Peter Garsden]

Great work as usual Phil.

I know exactly what you mean about blending the wing into the fuselage front and back which is made so much more complicated by the circular shape of the fuselage. Being a sloven and a heathen without your immaculate patience, I decided that the job of carving 3D shapes out of balsa with the attendant problem of thin balsa flaking, I decided to use milliput putty, which was so much easier. It may however be a bit heavier. That was the downside, also not really sandable, so you have to smooth it out with wet fingers before it sets, but you have 3 hours.

It is all on my blog - **LINK** if any of you keenies are as lacking in patience and want to finish 2nd?

[McG 6969]

Unbelievable again, Phil.

I'm staring at your pics with frozen eyes and reading your words with half open mouth...

I can't imagine I still have to perform all that... being left till now with not even half a wing built and still a third of the fuse to plank...

When did you wrote the Mass build fly-in will be... ??? ...

Cheers

Chris

[Phil Cooke]

Thanks for the comments Gents.

Chris, the Mass Build will be put back until a time when we can ensure everyone who wishes to take part in our event is free to travel to the UK from abroad and to enter Wales to fly. At present both are denied by the current situation, Wales is still on lockdown and it is an offence to cross the border for non essential activities like gliding.

Publically we've stated on the PSSA website September, but I already know of an important issue why potentially that will be pushed back to a later event. We have a planned fly-in in October too, which we could target, although by then the nights draw in pretty quick and our competition day wont quite feel like it should with the long, balmy summer afternoons and evenings.

So for now, in your mind, please target 5th/6th September as the date - with a high likelyhood that gets moved back to October 10th/11th. Either way, still plenty of build time left for the Sabres!

Edited By Phil Cooke on 26/05/2020 21:34:56

[Phil Cooke]

The rear fillets have proven tough to model accurately, I've done my best from the various photos I'd collected but in hindsight I dont think I've got the angle of the little ply base plates quite just right in pitch, I think mine are too flat and co-planar with the underside of the wing (which aerodynamically made sense to me!?)

Anyway, on with the pictorial description.

First, little ply base plates were cut to size from 1/32" and glued to the fuselage only.

From the other side they sit onto the balsa wing root fillet base creating a little step for the wing T/E to sit flush into.

The final shape and finish would be formed in P38, but to minimise the volume (and weight) of filler, balsa sheet was used to block out the void, leaving effectively only a 'skim' needed to finish the form.

Filler was applied upto a taped edge and then sanded back to form the flat section up front and then the concave radius at the rear. Again not easy to do without sanding the fuselage where it doesnt need it!

All done on one side, the next trick is to make another just like in on the other side!

Edited By Phil Cooke on 26/05/2020 21:56:26

[dirk tinck]

Great work Phil !The wing fit looks a lot like mine !I'm glad most builders unlike me still find the courage to go on in these weird times.Guess i need to re- find the right pace ....

[Austin Massey 1]

Don't lose your Mojo Dirk - you and Phil are my gurus.

I continue to make mistakes but still slogging on.

The lockdown has saved me the embarassment of not finishing on time, although it could still happen.

Austin

[Phil Cooke]

Dont worry too much Austin - there are many in the same boat of 'not finishing by the original target date' - myself included!! No problems - our event won't be for some months yet!!

With the brilliant pilot supplied 3D printed by Andy Meade - I had to sand him down a little to achieve the correct height in his seat, I also had to remove his legs below the knee to get him in up against the console I'd built. He got a good coat of primer today in readiness for some top coat paint and detail.

[John Donohoe]

Hi phil, have you got any total weight on the model yet. Thanks John

[Phil Cooke]

Nothing measured as yet John no, still a bit to do with glass and paint etc. I'm targeting 4lbs as per the Gamma Build example built from the same woodpack - but time will tell!?

Edited By Phil Cooke on 30/05/2020 21:16:17

[Phil Cooke]

A very theraputic couple of evenings with the paintbrush has the pilot and the seat, both 3D printed, ready for fitment (at a later stage admittedly) - but a nice break from all the sanding and glass work still ongoing!

[SR 71]

Hmm that looks nasty where the peg is inserted, nice job

[Phil Cooke]

The pilot and seat are all painted up, bar a little weathering later on - to be applied with the rest of the cockpit paint later on... that's enough time enjoying myself with the paintbrush for now. I need to push on with the final sanding of the fuselage before glass.

[dirk tinck]

Colorfull combo Phil !And a well detailed pilot !

I can't find any colored images of the Italian aerobatics team pilots so i improvised with a black and white photo next to me. I think they had bleu-ish suits.

Did you paint the flag on his shoulder ?Very nice !

[Phil Cooke]

Yes my pilot utilises a little artistic licence too. I think the team (short lived) flew with Orange helmets but I preferred the white and the little painted national flag added some detail - likely to be lost though once the canopy frame is painted I think as it will sit just below that eye level!

[McG 6969]

Great colorful driver indeed, Phil.

... but I'm afraid you still have to paint that little red star with yellow outline on the ex-Yugo flag...

Cheers

Chris

[Phil Cooke]

We'll see about the little red star on the tiny flag Chris...

The weather here was foul today with rain and high winds. I had hoped to get outside and finish my fuselage sanding but this was not possible, so I looked for a nice cosy indoor job to complete. I ended up dropping the wing servos in and programming the ailerons all ready for flight - jumping the queue a little maybe but it's all in need of doing.

The torque rods are angled with the wing sweep so the ball joints are essential to take out the arcing movement - it all works well with no slop.

One point of interest - I will need to cyano 'thread lock' the little white horns to the torque rods as any rotation here once set up effectively puts up or down trim onto the aileron, again an effect of the wing sweep. They don't move under operation, but could move during handling or transportation - a drop or two of glue will build more confidence in the set up.

[Phil Cooke]

I've set up and glued the fin into position today - measuring the fuselage was flat in its cradle then using a little plumb bob pinned to the centreline of the rudder T/E - very easy then to align down the centreline to ensure everything is square. I used 20 minute epoxy on the 2 glue areas front and rear to give me plenty of wiggle time.

A lot of the fin is left unsupported with a little gap between the 2 x F15 tailplane bearing formers... I've still got to add the triangular section at the base which will also help retain the fin, but I think I'll add some balsa wedges to further improve the bond.

The L/E ventral fin was pre-sanded in section a little then added as was the fillet blend piece, which I increased somewhat in size from that shown on the plan.

I've clearly cut my false rudder a little too deep, it only allows a tiny little T/E fillet which isnt quite big enough for true scale, but its there in character - still needs final shaping in this view.

[John Donohoe]

Hi Phil , is there an instrument panel to download and how do you get it to fit the size

[Peter Garsden]

I have shown an instrument panel that I used on my blog here if you want to use it.

[Phil Cooke]

Had a bit of time away from the Sabre with other commitments this past week, but back on the bench now! I've finally tackled the tricky fillet blend along the fin and the dorsal spine. But not without the use of a bit of filler. 9mm balsa triangular section runs across the fin base and onto the rear of the spine and then a fillet of filler does the rest. Also blending the fin base to the thinner spine section.

I'm not sure whats been going on but I've been having real trouble with my filler - it's setting with localised harder lumps in the mix, which arent there when I apply it as a paste - the variable density when sanded results in an orande peel like finish as opposed to a smooth iced cake! Not good at all - and all you can do is pick the harder lumps out from the surface and refill locally. I've not seen this before, its a relatively new pot of decent modellers filler??

[dirk tinck]

Hi Phil ,the only thing i can think of,as a cause of your filler problems is a reaction of a underlying product like glue ?

Maybe run a test piece ?

I can see now that your trailing edge fillet is vanished under the fin fillet ! I had thesame problem and i dropped a piece of the rudder onto the fin ...

Did you open up the channel for the elevator joiner ?Not enough travel ?My elevators are touching the fuse at their leading edge when i give full up(movement planwise )

Too late now to change.I hope i have enough ''up''with reduced elevator travel...

[Stephen Jones]

Posted by Phil Cooke on 06/06/2020 19:34:36:

We'll see about the little red star on the tiny flag Chris...

The weather here was foul today with rain and high winds. I had hoped to get outside and finish my fuselage sanding but this was not possible, so I looked for a nice cosy indoor job to complete. I ended up dropping the wing servos in and programming the ailerons all ready for flight - jumping the queue a little maybe but it's all in need of doing.

The torque rods are angled with the wing sweep so the ball joints are essential to take out the arcing movement - it all works well with no slop.

One point of interest - I will need to cyano 'thread lock' the little white horns to the torque rods as any rotation here once set up effectively puts up or down trim onto the aileron, again an effect of the wing sweep. They don't move under operation, but could move during handling or transportation - a drop or two of glue will build more confidence in the set up.

Hi, i have had problems with ball links on those torque rods i would put the ball links on the servo arms and the clevis onto the torque rods no need for glue.

Steve.

[Phil Cooke]

Hi Dirk,

Yeah in the last photo you can see where the 9mm triangular section over-runs the fin at the rear and swamps out the little T/E fillet. My rudder is cut too deep, too low - but its all fixed and glassed so no alteration will be done on that. However a little sanding of the triangular section gets you back to something quite characteristic of the real thing.

Still needs a little more thinning at the extreme rear - it should be the same thickness as the rudder Trailing edge all the way down. More careful sanding where needed - but only there!

Stephen - thanks for the comment - are you suggesting you've experienced the torque rod horns rotating due to the small moment about the rod in normal operation?? I can turn mine by hand but they are pretty tight on the threads - certainly wouldnt expect them to move during flight due to aerodynamic load. I did show I could knock them or move them with careless handling - which results in the aileron neutral position altering - but it takes some doing!