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Phil's F-86 Sabre build thread


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With the project launched 1st August when the G&M Models plans and short kit went on general sale, it's been great to see so much interest in the Sabre with folk already setting up build blogs and 'claiming' colour schemes - even though building isn't formally meant to begin until 1st November!

After some lengthy deliberation, I've taken the plunge and have finalised a choice of scheme for my take on this famous fighter - the distinctive Yellow and Blue stripes of 'Team Sabre' from the Yugoslavian Air Force - who I think flew 5 x F-86 during their short existence as a display team.

There's not many photos of the real examples on the net, but it seems quite a popular choice with the plastic modellers, and indeed the flight sim community too!

3-view from a plastic kit...

team sabre 3 view copy.jpg

A screen shot from a modern day PC based simulator...

team sabre simulated.jpg

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  • 2 months later...

Hi McG - no I'm not quite able to make a start on my Sabre yet due to other work taking up the bench and my time, I should be underway in a couple of weeks.

Plenty of time for this one with us not flying until mid June - our biggest build window yet at over 7 months - but I am conscious I'll be one of the last to start! That said I'm sure my build won't raise any issues not already admirably discribed and tackled in the threads up and running - those combined with Martin's Gamma build thread give us a rich reference guide!

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  • 1 month later...

Well, I'm a little delayed starting my Sabre with work and other projects getting somewhat in the way but I'm glad to report I'm finally now off and running!

Compared to some of the other brilliant builds already well underway on this forum, my Sabre will be a fairly basic build - no flaps, no rudder. I've elected to mount a pair of aileron servos centrally in the wing driving torque rods out to scale sized ailerons, enabling a draggeron mix for landing instead of flaps, and I will be fitting droppable fuel tanks as others are already doing - bar that it will be a simple, stock build.

With a JP150 fuselage still under final construction at the other end of the bench I have elected to make a start on the wing. First I made up the 4 wing skins, all oversize front and back. On the lower pair I then marked the position of all the ribs, main spar and sub T/E against extended lines on the board.

wing skin 1.jpg

Main spar and T/E added to the lower skins, I've beefed up the sub T/E a little on thickness - now 1/4" - to allow for the torque rod pivot inserts later in the build.

wing skin 2.jpg

'Gettin' Jiggy with it...' I must admit I think this is rather clever and i did enjoy slotting it together! nerd

wing skin 3.jpg

With the wing jig pinned out all square and true, and with R1 fitted with a 1.5mm cap to allow the wing sheeting to correctly seat on the inboard guide, the first wing skin can be offered up to its bed.

wing skin 4.jpg

Next job is to open up the spar slots and angle the T/E and L/E faces on each of the ribs for the sweep angles before they are dropped in one by one with a splash of cyano.

A little bit of inspiration... The blue stripes on this scheme seem to vary a lot from reference to reference - in this case - a 1/72 scale model - the stripes are more grey than blue! I will be sticking with a blue stripe and underbelly I think... but of course final paint selection is a problem for another day!

sabre scheme 1.jpg

Edited By Phil Cooke on 15/12/2019 00:00:19

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Great to have you finally on board, Phil. yes

I'am now hesitating to change my plans regarding the wing control surfaces, to skip the flaps and to go with the aileron torque rod idea w/ dual servos.

Is 2mm okay for the torque rod or should it be 3mm?

Is the 13gr Turnigy 90S metal gear as Martin uses (2,5kg @ 6V) still OK? or should I go for a 'heavier' one?

Apologies for being already asking daft questions... blush

IMHO, the French Blue color is looking a lot better than the 'grey' version.

Cheers

Chris

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Hiya Chris,

No 'right' answers here, I'm using torque rods in an attempt to keep the underside of the wing clean whilst still allowing an aerodynamic function to slow things up a little on landing - I've never been a big fan of drooping flaps on a low wing PSS model and the draggerons work really well on the A-4 and Hurricane.

I will be using 3mm torque rod material, I think 2mm is a little 'springy' in torsion. As for servos (not bought them yet) I will be using something like a Hitec 85MG like on the A-4, a well proven mini servo not too dissimilar to the Turnigy 90S MG.

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Hi Phil,

Thanks for your real fast answer.

Keeping the underside clean might be one of the major concerns on PSS apparently.

So I'll stick to your advices, using a 3mm rod and keep going with the 90S MGs as I already have them.

I'll wait in anger to your decision on how to go and design the torque rods... and 'stoutly' copy it... wink

Cheers

Chris

 

Edited By McG 6969 on 15/12/2019 18:49:56

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  • 3 weeks later...

Hello Phil,

First of all my best wishes for a great new decade and of course a successful PSSA outcome.

I'm looking forward to use some torque rods for my Sabre wing as I think you're planning to do.

You mentioned "scale sized ailerons", but are the torque not 'extremely' long then (even for 3mm diameter)?

Can the 'bearings' be styrene tubes or snake externals & not have the full length of the rod?

Should I 'thicken' the wing sub-trailing edge as you did right away when building yours?

How do you handle the wash-out of the aileron???

Apologies in advance for all those questions... blush

Cheers

Chris

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Hi Chris,

Happy New Year!! I've taken some time out away from my work and indeed my modelling over the past 2 weeks so I'm all charged now and ready to get my Sabre moving with some pace! - conscious I'm playing 'catch up' with so many builds approaching maturity!

No probs with all the questions, this is after all one of the key 'Mass Build' aims to share knowledge and ideas!

Yeah the M3 torque rods will be fine at this sort of span - no problems and well proven on previous builds like the Hurricane. Relatively the air speeds and aerodynamic loads on our PSS models are pretty low. With a scale aileron sitting just outboard of the wing pylon a standard 15" torque rod will suffice (mine are bought from SLEC) and these come pre fitted with 4 sections of pinned plastic tubes, it doesn't need a full length bearing tube, although of course this could be employed if desired.

I thought a thickened sub-T/E was a good idea only because the pins on these tubes would need a bit more purchase, they are 1/2" long - of course you could locally add balsa to thicken it up as shown for the hinges on the plan - same logic.

In my mind the washout question is the same whether you have full length ailerons or shorter ones for scale. As we know the main wing section has the washout incrementally built into its form from root to tip thanks to the clever wing jig... in all cases the strip aileron needs to be either twist warped (using steam or ammonia) along its length - to create the compliant shape (its only a couple of degrees along that length) or - as per the Jet Provost builds, you could use a slightly oversize aileron stock and sand the blended twist into the flying surface. I will use the ammonia method - before cutting the aileron section to length.

But Im not at that stage yet, I still have to complete my basic wing assembly! embarrassed

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Hi Phil,

Thanks for the wishes and for your guidelines.

I will be trying to make my own torque rods with 3mm piano wire then. Adding a few (three or four, I guess) styrene bearing tubes before bending. I don't mind buying the SLEC ones but the postage to BE probably triples the prize...

I also will be adding a bit of thickness (3mm) to the sub-T/E where needed between the hinge blocks. I already tried to remove those blocks intended for the flaps but the 'surgery' isn't worth it.

I think I go for the full length 'ammonia' method as well, but how do you 'fix' the triangular stock temporarily to the wing allowing the ammonia to evaporate... ?

Thanks again & cheers

Chris

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You can tack glue the aileron to the wing using 4 - 5 small blobs of thick superglue (CA) at intervals along the trailing edge. Once finished with the shaping just slide a sharp blade between the trailing edge and the aileron to cut through the blobs and release it. If you are bending/shaping the ailerons with this method I would also clamp the two ends of the aileron (root trailing edge and the wing tip) between some scrap balsa.

You might be able to get away with treating the aileron with water or ammonia and then putting the "twist" in by hand and then checking it against the wing, keep easing more bend in until it matches the correct root/tip profile. It maybe possible to accomplish by just brushing water onto the underside of the aileron and then twisting and clamping into place until the water dries off.

Best to do all this before you put any bevel of hinge cutouts in.

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Thank you for the guidelines, John A H. yes

Hi Phil,

Regarding the SLEC torque rods, the only ones I found are SL113-R and are only 14 swg, which seems to be just over 2mm diameter..?

I guess it would be an advantage if the clevis is adjustable at the servo end, but your 'Top Gun' A-4 seems to be using an non-threaded end?

Apologies for 'squatting' your thread again. blush

Cheers

Chris

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I'm sorry I'm not sure of the SLEC part number for the 3mm torque rods I've got, I bought them at a show not online, but I'd definitely go with 3mm for actuators of this sort of length, 2mm will be a little 'springy' which will lead to 'slop' at the aileron.

You only need adjustment at one end of the pushrod which connects the servo arm to the torque rod... each to their own on hardware fittings - I tend to use a small, sharp 90deg bend and a servo keeper on the servo end, and a threaded clevis onto the torque rod horn at the other. In this case, with the sweep on the Sabre wing, I will be using a ball link connector instead of a normal clevis to ensure any lateral movement at the torque rod is taken out without adversely loading the servo.

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Just for clarity, the only torque rods that SLEC currently list ARE the SL-113R. As Phil described, they do have the short lengths of white plastic bearings and they are most definitely 3mm wire diameter. I have used these in the last 7 models I have built and I've just had the calipers on a set to confirm.

SLEC have obviously just made an error in the description on their website.

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Thank you again, gents.

I will definitely follow your advice, Phil.

Using 3mm rods, but bending my own with styrene bearing tubes. Due to the swept wing, I already thought of using ball links for the servo connection.

@ Alan > thank you for getting your calipers to the rescue, but indeed the SL-113R are listed as being 14 swg. I guess if or when the pros are making those 'errors', it can get very confusing for apprentices like me... indecision

Cheers

Chris

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Finally a bit of proper construction!

Having chamfered the lower spar slots and T/E on each of the ribs (for the sweep) I dropped each wing rib into the skins with a quick lick of thin cyano. I started the job with the intention of building 2 separate panels to aid handling whilst shaping of L/E and T/E later, but when I came to fit R1 it felt like a good idea to join them perfectly flat as a pair and add them as one thick rib - which is what I did - meaning its now a one piece wing with dihedral. I might come to regret that later as it wont help sanding...

ribs build 1.jpg

Chris McG 6969 - here's the SLEC torque rods for reference... they are 14" long as supplied - not 15" as I previously stated - apols.

torque rods.jpg

Anyway all the ribs are in and the lower skins have taken the form of the wing jig nicely... next job is to chamfer the top slots for the upper spars before that and the webbing is added along with the sub L/E. All simple and enjoyable building!

ribs build 2.jpg

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Good idea to make 2 at once Phil which is what I did and it is not a problem with the jig, which lines everything up perfectly. Presume you have added 1.5mm to the R1 jig though? Accurate neat building as usual!

Torque rods are definitely more slop free than mounting in the wing and the way to go with just ailerons. I have done flaps and decided not to attempt the fuselage side spoilers - way too much of a fiddle and won't be needed with flaps. Flaps not really needed on a PSS model anyway as they won't be going fast enough.

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Well I'm committed now with a one peice wing so early in the build...I'll manage but I'm still convinced handling and shaping the panels would have been easier done as singles...using the jig to finally bring them together.

I was a little hasty in my 'next steps' commentary last night as I'd forgotten I needed to prepare the drop tank mounting slots before adding the top spar and webbing... so this has been this afternoons work following the leading examples set by John Hey and Harry Twist.

Deviating slightly, I'm intending to use a pair of snakes with M2 metal end fittings to enable the pylon drop, but again like John and Harry, working from a single, centrally mounted servo.

The drop tank pylons sit between Ribs 8 and 9 so the first job was to make a set of semi-rib mounts - cut from a sturdy piece of 1/4" balsa and sized just a tad smaller than R8.

pylon mount 1.jpg

The inner faces of the slot are to be lined with smooth 1/16" marine ply, 1/8" spacers ensure the pylon mount is a well toleranced, robust fit. Here's a kit of parts prior to final assembly...

pylon mount 2.jpg

...and the fully assembled unit showing the ply lined 'box' - sized at 1" x 1/8".

pylon mount 3.jpg

Here's the assembly dry fitted into the wing between Ribs 8 and 9. I will have to arrange the snake, make up and drill the holes at the required angle and position prior to fitting these into the wings. I'm intending to cut slots in the inboard ribs allowing a straight snake section to 'drop in' without any pre-load, I will then re-cap the rib sections I've cut away and that should be that!?

pylon mount 4.jpg

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You can't make a model without a bit of mess - but I do try to clean up a little for my photos Dirk smile d

Trying to put off the delicate job of drilling the oblique holes into the pylon mounts I trimmed all the rib L/E to the correct angle and sanded them back to the correct line with the help of a little sanding tool I made - cut from a length of 1/2" triangular stock. This was sized to 'bridge' 3 ribs ensuring that they all stayed true and proved very useful! Once all cut back I made up the sub L/E from balsa sheet.

sanding le 1.jpg

The reason I wasn't looking forward to the drilling task was that I don't own a pillar drill, this was always going to be down to a steady hand and eye... those with a H&S background please look away!

I mounted my Dremel onto the bench with a sturdy grip, checking the cutting tool was all square to my bench. I then elevated the work peice to the correct height by selecting some wood stock of the required thickness... With datums drawn and a steady hand we proceeded with the cut, keeping the workpiece flat on the bench and pulling it towards me onto the Dremel along the datums - with a keen eye from above!

drilling 1.jpg

drilling 2.jpg

The hole was cleaned up and the snake outer proved a good snug fit through the balsa/ply/balsa laminate.

drilling 3.jpg

I still had all my eyes and fingers in place - so I proceeded to cut the same hole in the other side!

Edited By Phil Cooke on 05/01/2020 18:36:20

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