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Phil's F-86 Sabre build thread


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The fin was completed with the cross grain tip piece and I cut the former slots and elevator horn clearances to enable the first trial fit of the fin and tail units.

fin fit 1.jpg

fin fit 2.jpg

Quite happy with that for a first trial assembly, I think I still need to elongate the arcing slot for the trailing elevator rod as there's not a lot of movement yet - now to shape and fit these pesky tailplane side cheeks which I've cut from 1/2" balsa this morning.

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For anyone not wishing to follow Dirk's brave lead and cut scale gun ports into your sanded fuselage - here are two other options for you to consider.

gun port decals.jpg

1. Laser cut, self adhesive black vinyl decals - scaled and positioned from the full size photo below. These can simply be positioned and applied to your finished model as a group using the backing paper provided.

2. Laser cut, self adhesive spray masks - for anyone wishing to add some shaded ports to their chosen scheme with the airbrush.

f-86 cockpit 4.jpg

Many thanks to our very own Matt Jones for taking the time to create and supply these - I have 12 sets of decals and 5 sets of masks available - if you would like one, please drop me a mail with your address to [email protected] - it'll cost you just the postage.

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A great weekend for sanding weather wise - with sunny spells and a stiff breeze blowing all the dust down the garden - got the wing out on the workbench and took back the L/E, T/E and wingtip stock in profile just now in need of final rounding. I glued the ailerons on with 2 tiny drops of thin cyano to allow them to be sanded and blended accurately with the tip. You can see the thin ply insert in the middle of the wingtip sandwich which gives the nice stiff T/E corner.

wingtip sand 1.jpg

wingtip sand 2.jpg

I can now break the ailerons off their glue spots, allowing me to complete the aileron hinging and the L/E dowel arrangement.

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I've also cracked the tail end this weekend with the elevator 'cheeks' and the exhaust shroud now all complete. I've altered the arrangement slightly from the plan in that I've elected not to extend the cheeks beyond F10 rearwards, deciding instead to terminate them flush with F10 then adding a shaped balsa block to create the extreme rear end.

I wasn't totally happy with the profile shape of the exhaust shroud on the plan - all my 3 views suggested it had a much more prominent vertical edge with a smaller radius.

tailcone 1.jpg

So I made one up from 4 laminates of 3/4" balsa cut out on the band saw.

tailcone 3.jpg

Before I could add this to the fuselage I needed to fit the tailplane cheeks which were shaped as per the drawing but for their shorter length rear. These needed a good sanding to get them to sit on the 45 degree slope just below the fin base. Much skin was removed from ones fingers with the Permagrit tooling involved!

tailcone 4.jpg

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To avoid oversanding, I found the use of a marker pen of great value - you can sand the slope angle just up to the sharp green/balsa edge safe in the knowledge you've not over done it and altered the required side profile.

tailcone 5.jpg

I was worried earlier in the week how this job would go but it was simple in the end, the cheeks were soon made to fit quite accurately. I removed the trailing arm of the elevator actuator for ease whilst fitting the cheeks - an arcing slot is still required to replicate that in F15.

tailcone 6.jpg

The cheeks are not mounted parallel to F15 but splay out towards the front only touching the ply tail formers at the back - they were angled purely by eye - but to get them at least symmetrical I made a little paper gauge and taped it to the fus about the centreline.

tailcone 7.jpg

Edited By Phil Cooke on 08/03/2020 20:40:22

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Hi Phil

Have just added the tail cone to my F-86 also, and have noticed that when sanding and shaping the fus around the tail cone and nose cone that I will require some filler. What is the best filler to use? I am a little worried that the planking has become a little thin in a few spots, my planking may not be the best!!! What finish will you be applying to your fus? Is fibre glass an option? All the best, thanks Dallas

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Hi Dallas, any lightweight filler should suffice, I tend to use either Polycell lightweight filler or I sometimes buy the Deluxe Materials Model Lite filler - both are ideal for our purpose. 'Normal' fillers are too heavy so try steer away from them.

I will be glassing my model to give a nice robust finish. 25g/m2 cloth and resins from Fighteraces are my preferred materials. You will need a good smooth surface to glass onto though, so the sanding (and filling if required) is essential and worthy of taking your time to make it all right!

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With my cockpit floor mounted on top of the battery box I was in need of a hybrid 3/4 depth seat and pilot as sketched cartoon style on my plan. Andy Meade pulled out all the stops and I received this excellent 3D printed seat and pilot made to measure the required depth - brilliant job as always Andy - much appreciated!!

cockpit fit 1.jpg

As you can see on the plan, F4 needs to be cut away to allow the seat to be positioned correctly, and sadly this caused some rework with my elevator servo mount, which (of course) I'd firmly anchored to F4. Bad planning by me. So before cutting the front of that away I added some additional triangular mounts to the rear of F5, bolstering the servo mount at both ends before the front extension was removed.

cockpit fit 3.jpg

cockpit fit 2.jpg

cockpit fit 4.jpg

I extended the cockpit floor rearwards of F4 and that was about that - the seat and pilot could now be fitted and checked for height - all looking good! Whilst I was here, I added some very basic side console panels which will help bring the 3/4 depth cockpit to life later - all just soft balsa block.

cockpit fit 5.jpg

cockpit fit 6.jpg

Andy supplied a range of different pilot heads which can be postioned - visor up, visor down, mask/no mask etc - I like this one best personally - and it means I dont have to paint his eyes!! I'm still to glue his arms on too but we'll fly on autopilot with no inputs required for a little longer yet!

cockpit fit 7.jpg

Edited By Phil Cooke on 15/03/2020 15:54:17

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  • 2 weeks later...

Following Dirk's advice I'm keen to finish the basic wing with glass cloth before it gets 'man-handled' in sizing and fitting out the fuselage wing saddle, blend fillets, location dowels and bolts etc. The drop tank work also benefits from having a glassed wing section.

So in between planned link-calls (with working from home) I've got a bit more done today, sanding the wings L/E ply face to section and hinging the ailerons.

I've used the small robart 'knuckle' type hinges, centrally mounted with offset reliefs cut into the ailerons.

wing hinges 2.jpg

wing hinges 3.jpg

wing hinges 4.jpg

The belly pan will be added to the wing after the initial glassing, then reglassed. Bar final sanding thats the wing ready for glass now...

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Hi Andy,

Only Chris' Sabre Dog variant was built without the tailplane dihedral - that is scale for that type (I dont understand the aerodynamics myself?) but certainly if you are building a more regular F-86 then the tailplane dihedral is the only way to go for scale.

As for levelling the tail actuator, if you have glued the 2 fuselage halves together without misalignment then the grooves pre cut in F-15 will ensure the actuator sits level - or as level as it needs to be - the width of those slots will need opening up to suit the brass tube you use as a pivot, but the depth of those slots is pre-cut and determines the angle of the tailplane axle. I can't say mine is accurate to 2 decimal places either, and there's loads more tolerance stack up yet to come with the fitment of the tails onto the bent rods. Only once its all set up with the wing and fin assembled can you really stand back and say its all symetrical, and make the required ajustments then as necessary - bending rods or opening out tailplane slots etc.

Dirk - the 1/32" ply sandwich filler in the tip blocks allows you to sand right down to that thickness (and thinner if you wish) at the T/E and it all remains very stiff and robust. I hate soft perishable T/E corners too!

Edited By Phil Cooke on 26/03/2020 07:34:01

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Hi Phil,

Hello Andy,

The Dog version of the F-86 has indeed no dihedral for the elevators.

There are a few other 'exceptions' like the F2-J Fury and the F3-J, both being the Navy and Marine Corps versions of the Sabre. They were heavily modified for carrier use like '6-3'-type folding wings, longer nose strut and a different canopy for better visibility, amongst other mods.

fj-2_fury_vmf-312_c1955.jpg

As Phil stated, the more 'regular' types of F-86s do have 10° dihedral for the elevator.

Please don't ask me what the aerodynamic result might be in both cases as I have no clue... blush

Cheers

Chris

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I was already past the wingtips when i saw the tip regarding the wing-tip ply doubler Phil...I will keep it in mind .

Regarding the tail dihedral :Maybe they use them as tailerons ?With dihedral it becomes in fact a V-tail . So with aileron input you get an amount of rudder also. Just an ideasad

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Started a job today I've not been looking forward to for a while... marking out and cutting back the wing saddle in the fuselage sides...

I used the 'sharpened metal rod' method as described very well in Steve Houghton's build blog. Using the inner ply formers as a guide, this worked well to 'prick out' a curved line just proud of the final required shape. That material was cut out by hand and I used a length of 2" dia plastic pipe with some decent grit paper glued to it to sand out to the required profile. The central overhanging ply former was tackled with the Dremel and a grinding wheel. Still a bit to do fore and aft of the ply saddle formers where the profile runs out, I'll complete that once the wing is married up. I'm conscious too that more material is needed off to allow for the thickness of the wing fillet foundation - (1/32 balsa or ply normally) - so more shaping ahead.

wing seat.jpg

With the top planking complete I could trim back the cockpit area to suit the canopy. The canopy was trimmed to shape and fitted delicately to the fus to enable me to trace the edge onto the planking. That line was then offset by 10mm inboard to form the curved edge of the cockpit lip. i made a little sanding tool to help here.

cockpit cavity 1.jpg

After I finished this and refitted the canopy I felt that 10mm was too much by eye, so I offset again by another 3mm giving a 7mm lip to the canopy, this looked a lot better IMO. I've still to make up the canopy blend at the front, something to complete once I've sanded my planking...

cockpit cavity 2.jpg

I cut my canopy to the line as evident in the Vortex canopy, I think there's a little meat on the canopy still cut at this position - it sits a little high for me, what do others think? Maybe the line is conservative, feels like another 5mm could come off this in height for scale?

cockpit cavity 3.jpg

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