Mike Chantler Posted July 31, 2023 Share Posted July 31, 2023 Have decided to have a go at build Paul Janssens' Spitfire 🙂 He did a plan for it in QFI Aug/Sep 2000, it's on Outerzone and there's an RCGroups build log. I was kind of intrigued by the multi panel foam wing that he used to make the elliptical shape and I get the feeling that his planes are designed to fly in lighter lift which suits our gentle hills better. However, I can't bring myself to do the lost foam technique so I'm going to build the fuselage differently but have not decided quite how yet! Thinking about carving the fus from XPS made me think that it would be quite a challenge to get the exhaust/engine head blisters right as quite a few of my fuselage carvings have come out as bananas 🤔 So plan is to do wing exactly as plan. But, very naively, I thought I'd 'knock up' a 3D model in Fusion 360 😩to see what it looked like as there aren't very many good cross sections around for the nose. Now I know why the Spitfire was expensive to build - every surface seems to be a complex curve that has to fit very carefully with all the other complex curves. And I have found lofting extraordinarily challenging to say the least!!! Anyway - wings will be conventional foam/veneer, but fuselage will be a mixture of 3D print (at least for spinner and exhausts/blisters) rear fus carved from XPS and tail feathers may be sheet as per original design. 2 Quote Link to comment Share on other sites More sharing options...
MattyB Posted July 31, 2023 Share Posted July 31, 2023 I used to own Paul's original Macchi 202, and can confirm his designs fly very well in light/medium lift. It was one of my favourites, but had a very dodgy elevator linkage that was not easy to fix becasuse of the design of the rear fuselage, and in the end I didn't fly it enough to warrant keping it, so I sold it on. Almost certainly a mistake, but hey ho! In breaking news(!) I also have one of Paul's fibreglass (possibly polyester) fuselages in my loft for this very model. It is on my "to build on retirement" list, but if you are keen to progress I am happy to let it go to you for a reasonable price. Send me a PM if you're interested. Quote Link to comment Share on other sites More sharing options...
MattyB Posted July 31, 2023 Share Posted July 31, 2023 (edited) Macchi in flight over the Lleyn 15 years ago (on a very old camera!).... I've also flown his slab sided P-51 that was built by a member of the LMAC; that flew very well too in light/med conditions. Janssens designs are definitely under-rated... Edited July 31, 2023 by MattyB 2 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted July 31, 2023 Author Share Posted July 31, 2023 Guess that is the 202 in your pic? looks very nice 🙂 Good to hear about the good performance and many thanks for the generous offer. At the moment I'm determined to carry on a bit with Fusion 360 as it's become a bit of a challenge for me, but I would not be surprised if I did not throw it in the 'delete bin'! It's such a frustrating process when learning from scratch. However, in 2 or 3 weeks I may come back to you for that offer if it's still available. PS Coincidently I have Paul Jansses’ original T33 – he has an amazing number of designs. Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted July 31, 2023 Author Share Posted July 31, 2023 Ha! crossed posts 🙂 Nice vid! Quote Link to comment Share on other sites More sharing options...
MattyB Posted July 31, 2023 Share Posted July 31, 2023 1 hour ago, Mike Chantler said: ...but I would not be surprised if I did not throw it in the 'delete bin'! It's such a frustrating process when learning from scratch. However, in 2 or 3 weeks I may come back to you for that offer if it's still available. As I haven't built it in the ~12 years I've had the fuselage, I'm pretty certain I won't knock up the model in the next 3 weeks...! 😉 Quote Link to comment Share on other sites More sharing options...
MattyB Posted July 31, 2023 Share Posted July 31, 2023 1 hour ago, Mike Chantler said: Guess that is the 202 in your pic? looks very nice 🙂 Good to hear about the good performance and many thanks for the generous offer. Yes, that's the 202 - better pics from this thread on RC Groups... (Bonus points if you can name the UK PSS guru behind me... 😉) 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted July 31, 2023 Author Share Posted July 31, 2023 Beautiful looking plane, now thinking spitfire camouflage is slightly dowdy 🙂 And I obviously don't get out of the Pentlands enough to recognise PSS fliers lol Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted July 31, 2023 Author Share Posted July 31, 2023 So cut the 6 sections for the wing, actually think it might be easier using a swing arm and physical sections for this, as left the stepper motor machine at 1m width - at which you start to lose some accuracy at the edges, so took me two goes for the first wing. Of course you have to align and glue the beds together as well, which took more time than I expected - and began to think I might be faster doing built-up balsa 🤔 Prefer this Technic glue stuff to others as it sands more easily. Now ready for skins. 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted July 31, 2023 Author Share Posted July 31, 2023 used DevWingFoam to setup the panels and sections: Imported Paul's plan to set it out. Airfoil is HQ 2.5/10 which is not one I have come across before (it's not specified in the plan but I seem to remember reading somewhere that this is what was used and by eye seems an ok fit with the drawings). 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted July 31, 2023 Share Posted July 31, 2023 (edited) Yep, he always used HQ 2.5 at various thicknesses; it's a great section for WW2 PSS models. Edited July 31, 2023 by MattyB 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 Tested root against 3D print of profile to reassure myself that 3d model is ok and I surprised that it is nice and reasonably in agreement: 🙂 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 Had bit of a disaster last month when bagging a wing which i had not done for a while. Dry run pulled 0.4 bar but must have added a leak that my puny £12 pump could not cope with, and ended up with .2 bar, thought I might get away with it but: Also the veneer was much thinner and 'bubbly" than I have used before - so result had to be binned 😞 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 (edited) So, new bag, extra careful with assembling everything, and pulled .5 bar 🙂, also used old 'flat'' thicker veneer, more generous with epoxy , New quick release connector to bag definitely made assembly less fraught: Edited August 1, 2023 by Mike Chantler 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 1, 2023 Share Posted August 1, 2023 (edited) Bagging is great fun once you get the hang of it. I have reversed aquarium pump for stuff that doens't need too much pressure (run constantly rather than on a pressure switch), and an old nebulizer for when more is needed. The crack of mylars releasing is very satisfying sound! Unfortunately I haven't probably used either setup for 10 years due to reduced modelling time (blooming small people...!). Edited August 1, 2023 by MattyB Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 hmmm... yes I think I'll have to bite the bullet at some stage and buy a better pump. And forgot I meant to have a look at using mylars and glass + veneer - did have a go ages back at glass only, but ended with dimpled texture as the plastic I used was too flexible. I do now have some .5mm mylar but am reluctant to use it as I found it very difficult to source! (not to mention I find the whole process a bit frightening). Anyway - pulled the veneer only wing out and it's good enough to use (ish). Everything stuck, but LE veneer overhang a bit crushed - but will just sand/cut this off: Fluff is from the breather getting stuck to the veneer where the epoxy leaked out 🙂 Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 1, 2023 Share Posted August 1, 2023 (edited) 20 hours ago, Mike Chantler said: Beautiful looking plane, now thinking spitfire camouflage is slightly dowdy 🙂 And I obviously don't get out of the Pentlands enough to recognise PSS fliers lol You wouldn't be thinking that when it got it's first bit of hanger/flight rash - this pattern was murder to put right after a repair! 🤣 PS - The other pilot is Andy Blackburn of numerous PSS plans fame, including the Provost that was the subject of a PSSA mass build some time ago... https://www.pssaonline.co.uk/product/h-p-jet-provost-t-3-t-4/ Edited August 1, 2023 by MattyB Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 1, 2023 Share Posted August 1, 2023 (edited) 13 minutes ago, Mike Chantler said: And forgot I meant to have a look at using mylars and glass + veneer - did have a go ages back at glass only, but ended with dimpled texture as the plastic I used was too flexible. I do now have some .5mm mylar but am reluctant to use it as I found it very difficult to source! (not to mention I find the whole process a bit frightening). I have never used actual mylar for the reasons you describe. A much cheaper and easier to source alternative is laminating film; you can use the A3 pockets for smaller jobs (laminated to itself using an iron or laminating machine, then cooled under weights), or just double over two layers of 250 micron off a roll and iron it to itself. This works fine with a polish beforehand, then apply the paint, though if you want the absolute best finish I'm sure mylar is better. From the ISA Limit EX group build many moons ago... https://www.rcgroups.com/forums/showthread.php?1385270-Limit-EX-ISA-mass-build/page16#post20811663 https://www.rcgroups.com/forums/showpost.php?p=21050310&postcount=252 Edited August 1, 2023 by MattyB Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 Brilliant! Thanks Matty, I will definitely check this method out, looks great, I can even experiment by tripling up some A3 150 micron pouches I got by mistake (meant to buy more 75 micron for covering a 60" plank - only discovered it was 150 when I tried to get it to go round a sub TE that had a nice square edge 🤔 ) Nebuliser pumps look good (I have an oil vacuum pump but never used it as it sprays a fine sheen of oil everywhere if you don't have exhaust trunking) 😞 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 skins look fine so added 6mm balsa sub LE, this will get an additional 3mm cedar LE once shaped a bit: This is slightly different as I think Paul recommended a single 5 mm balsa LE, but I wasn't confident of getting the elliptical(ish) shape and also like the ding protection of cedar. Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 1, 2023 Author Share Posted August 1, 2023 Normally I always forget at least one thing in the sequence, which usually sends me into a panic of sticky epoxy gloves and newspaper and things get covered in sticky epoxy that shouldn't 😮. So, wrote an aide memoire for myself: apologies , I'm sticking it here, as know I'll have no clue where I have stored it if I don't put it in the build log 🙂 1 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 1, 2023 Share Posted August 1, 2023 There is rather a lot to remember when bagging, I’ll give you that! I wrote a similar checklist and had several “dry” rehearsals before I bagged my first wing, but still forgot one small element; luckily it did not affect the result too much. Practice makes perfect! 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 2, 2023 Share Posted August 2, 2023 15 hours ago, Mike Chantler said: skins look fine so added 6mm balsa sub LE, this will get an additional 3mm cedar LE once shaped a bit: This is slightly different as I think Paul recommended a single 5 mm balsa LE, but I wasn't confident of getting the elliptical(ish) shape and also like the ding protection of cedar. Good idea. Just one point - don't forget to drill at least a pilot hole holes for the dowel cannons before you shape the LE of the cedar, otherwise you may have some "fun" trying to get them in the right place! Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted August 2, 2023 Author Share Posted August 2, 2023 Damn, and good point, got excited about the build and added/shaped cedar 🙄 I'm finding that the Titebond Original sets really quickly - so couldn't resist shaping lol 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 2, 2023 Share Posted August 2, 2023 Never mind - with a suitable bodger to mark the position in the LE first you should still be able to get them in there; just go very carefully with a small pilot drill first before you commit to the dowel sized one! Quote Link to comment Share on other sites More sharing options...
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