Jump to content

PSS A-10 Thunderbolt II - build blog


Phil Cooke
 Share

Recommended Posts

glass looks really smooth, do you have to do much filling before covering in brown paper and glass? - am intrigued,  as spent ages using filler on XPS then applying glass, then filling/sanding several times, followed by deep primer, more sanding ... still not sure I am doing it the best way. Does the density of the foam make a big difference - I seem to ding it really easily on the bench. Your finish already looks really good 

Link to comment
Share on other sites

Hi Mike, no the blue foam is sanded to shape and the brown paper is applied directly to that surface with PVA.  If the blue foam (a dense material) is sanded smooth with a fine grade paper to finish the paper finish is smooth.  The glass goes ontop of that very well - the purpose of the glass really is to give a more stable surface to prime and paint onto - although with resins it does harden it all up nicely too - the paper can easily scuff and that would then soak up paint etc.

  • Like 1
Link to comment
Share on other sites

The brown paper is 'stiffer' - or less compliant - than the glass cloth so at a micro level it 'bridges' the surface finish imperfections of the foam much better - glassing onto foam direct would leave a less perfect surface, slightly orange peely(?) and less durable too... The brown paper and pva is cheaper, builds to a better surface which can then be glassed upon.  1 layer of glass is all thats needed onto the paper.  The glass cloth I use is 25g/m2 - and you add a similar amount of resin - I'm not quite sure how this compares to brown paper/pva?  Multiple layers of glass/resin would be very time consuming, very expensive and I'm pretty sure, heavier too.

  • Like 2
Link to comment
Share on other sites

Brilliant, will definitely try this, I would think this would be much more robust and a lot quicker than filler on XPS, then single 25gm2, which took me ages (partly due to me comming up the sanding/filling learning curve). It's far too easy to ding the unprotected foam when you are impatient with filler and sanding. 

 

Thanks for the tips 

 

Mike

Link to comment
Share on other sites

Another good session today on the A-10...

The recently glassed nose section was cut back with medium paper and has had 2 good coats of filler primer with a focussed sanding in-between after a 24hr wait for it to fully harden.  Surface is looking pretty good, just a few low spots still to address...

 

IMG_6021.thumb.JPG.03928c986b12bfd92edfa5ac96ef888b.JPG

 

IMG_6023.thumb.JPG.d8b9d0f41e14d0ab96042585f81c32d2.JPG

 

In between waiting for the primer to harden each time round I've done a bit more glassing - tailplane lower surface this time and I've added some resin to the lite-ply end caps on the elevators and rudders - areas that dont naturally receive glass but still need to be painted.  I'll soon have all these parts in primer too now I hope.

 

IMG_6027.thumb.JPG.116eb7bc73c0f7e780a670adde970b3b.JPG

 

IMG_6029.thumb.JPG.6edc3d65d824af768f3e6f9f7fd5a464.JPG

  • Like 3
Link to comment
Share on other sites

Good work as always Phil. Delighted to see this progressing - then maybe the 2nd Tornado? And the big JP? And the Vulcan? No pressure you understand!

 

Aren't you using Freddy's Sauce? I found it amazing on my Spitfire and filled the weave a lot quicker than primer. If you want to look at my Spitfire Blog you will discover the delights of the sauce Mike which is equal combinations of water based varnish, talcum power, and lightweight filler, with an acrylic colour added to suit. From what you said Phil, you may have mixed your version too thickly because mine spread like sauce?

Link to comment
Share on other sites

Hiya Pete - yeah I used the same sauce mix on the PSS Sabre - and although I was very happy with how it went on, how easy it was to sand and the initial finish it provided for the top primer and paint - I've seen over time it isnt as hard as the resin, in fact my Sabre fuselage is very susceptible still to minor surface damage - seen in storage and transportation already... I just thought for this bigger, heavier model which is bound to be manhandled at the slope I would make it as tough as I could - hence resin and paint only - a conscious decision this time.

Link to comment
Share on other sites

It's been some time since I've done any work on the 2 fins but now the interfacing tailplane is glassed these needed a bit of work to ensure they still fit snugly. 

 

Whilst I had them on the bench I fitted the 2 rudder servos and the aero covers which required some little hardwood mounts cut from the type of block you buy to mount cowls on fuselages.  The small green tool I made to aid with fitting the blocks with the right recess - it was a right angle of the same thickness as the white plastic cover - shaped to allow you to hold the block in place with the green alignment tool flush to the surface - once each block is positioned you can remove the green tool and add some glue - worked well.

 

IMG_6074.thumb.JPG.08004d91465a4823419fbabfe7655f73.JPG

 

IMG_6076.thumb.JPG.2e0e29e5dd70fc6915d2d3edb2e7f451.JPG

 

IMG_6077.thumb.JPG.8aff7edd7a131449b00756037150f3eb.JPG

 

The little fibrelgass rudder horn still needs to be fitted in the slot to the right - these parts are then ready for a final sand and primer.

  • Like 3
Link to comment
Share on other sites

Some more work achieved today on the tailplane mount which now all aligns and bolts up nicely into the rear fuselage.  I still need to set the incidence of the tail relative to the wing but this will be done later after more work is completed around the wing-root.

 

Tailplane has a pair of carbon rods for location dowels at the front and is held in place now with 2 x 5mm nylon bolts reacting against a ply load spreader towards the rear.

IMG_6171.thumb.JPG.ac9d59e0d62bb3fc62788f50600a1ab7.JPG

 

Captive nuts into the ply housing - positioned here for the camera - they have since been reversed so the bolts pull them through the ply when loaded.

IMG_6173.thumb.JPG.16bf32bea2cba52d31ffb8aadf87eca3.JPG

 

All nice and square and secure.  With this now fitted I'm hoping for a full rig photo this weekend if the weather is kind enough.

IMG_6167.thumb.JPG.cfe3225703e0534178023c929b08749b.JPG

  • Like 5
Link to comment
Share on other sites

Weather was poor today with freezing fog throughout most of the day - so no rigging and no photo in the garden...

 

Instead I final sanded all of the tailplane, elevators, fins and rudders and gave them all their first coat of filler primer.  The foam was placed inside the servo bays to avoid overspray.  Quite happy with the finish, there are a few pin holes now evident in the fins where I was too tight with the resin (I glassed these some time back) and some damaged/pulled weave areas in the cloth on the tail - a little 3M putty will sort all those out before another sand ready for the final grey primer.

 

IMG_6212.thumb.JPG.2879a82e4cd82343aee3539073a42c3b.JPG

 

I did a little more canopy fitting and alignment checking to the front fuselage too, still some work needed here... the canopy is formed in quite a thick material - almost 1/16" - I somehow need to blend that edge into the fuselage all round.

IMG_6208.thumb.JPG.05b68331b2a24555684619e847c17179.JPG

  • Like 7
Link to comment
Share on other sites

  • 2 weeks later...

Perfect weather this morning for a full A-10 rig and a good walk-around to refresh my mind on the 'still to do' list - which despite a complete looking airframe, is still quite extensive before we are ready for the slope.

 

EDITIMG_6424.thumb.jpg.fca8e982801eb7753ff88debb594dbd5.jpg

 

Fuselage sections all went together well and the engine pods were fitted for the first time in many years!  The nose section still needs all the cockpit fitting out with seat and pilot before the canopy is trimmed and blend fitted. The rear fuselage still needs the wing incidence bars fitting aft of the main wing joiner, and the huge wing root fillets still need to be added.  On the top of the engine pylons there are complex fillets needed too between the pylon and the nacelle.  Once all thats done the tailplane incidence needs to be fixed and a belly pan made for the tailplane. 

 

EDITIMG_9695.thumb.jpeg.2bea26bf13c248f375ee55b0c680c971.jpeg

 

The wings are effectively complete ready for glass, but I still have to fit the wingtips which were taped on here for effect - the routing of strobe lighting cables is all thats stopping those being fitted.

Fully rigged in this guise it has an AUW of 30lb.  Theres still a few more lbs to add, with 8 servos, 2 batteries, wiring, seat, pilot, glass and paint etc.

 

EDITIMG_9686.thumb.jpeg.5169b19aa85b7717011dbcee6cfff6bb.jpeg

 

EDITIMG_9692.thumb.jpeg.e45362021605f3dee5a4f95b6aedd6de.jpeg

 

 

  • Like 7
Link to comment
Share on other sites

  • 10 months later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...