finishing my BT 61.5 Corsair

[Shane Sunday]

I've enjoyed building from this plan. Most people say his 82 inch model is far better and more worth while building. I'm just hoping my changes work and allow my wing to not only be strong but my retracts to be sturdy and reliable.ive spent the last couple days getting the tail end sorted. I dont think I've ever meazured something so many times. So im hopeing everything is square but those tail feathers are now glued in place. While that is setting up I've turned my attention and thoughtsnto the front of the model. This is roughly a 1/8 scale model and the R2800 radial is 52.8 inches in diameter. So me calculations are thusly, im not great at maths but... 52.8 × 0.125 = 6.6. So I will need to find a head on photo of the engine and shrink it to 6.6 inches then redraw the cylinders to scale in illustrator so I can get a start on making something that looks like a powerful R2800 and not a piece of plastic. To be honest I'm feeling confident because I think I got the maths right.

I'll post some photos of the tail tomorrow. now to hunt an image.

[Shane Sunday]

Sorry fellas I had said I was going to post some photos of work being done. TBH it's best done on my computer as my tablet is horrible at it.

Bellow you can see what I've done with my tail wheel. It's still got some work but it's getting there.

here is how the tail feathers are coming along. I've mounted them and noticed that onw side of the vertical stab is a little portly so work must continue to make it look right and save weight.

oh it's starting to look like something alright. I'm also shaving and reshaping the horizontal stab as well. I started this build so long ago I guess I thought I was goin to fly a block of lead.

this area needs finished off as well I may tear that structure apart and stick a bit of blue foam and shape it. I could build upon what's there but is it worth adding too much weight in the rear? I think the foam will be lighter.

Also I managed to get my hands on some micro balloons. This should fill the space between the wing and the fuse rightly. Little by little.

[Shane Sunday]

I've been hacking away at blue foam in an attempt to resculpt the tail end. The use of a hot knife a couple sanding blocks and the edge of mywork bench. Sure ill let the pics tell the story.

Time to shape

Always more to do. Sand and shape sand and shape. Using the edge of the balsa fuse and a 6x6 spruce stick with sand paper on an end helped to feather the shape. Little by little.

[Nev]

I never like doing these fillets, too many arty curves and not enough measuring and cutting.

Yours are looking good though and got to be good for weight saving.

Nev.

[Shane Sunday]

Thanks Nev. I keep looking at the tail of a small model im using as reference and the blend I'm working on looks completely different from what I see on the model. Also I think I need to extend the prutrusion that holds a nav light. Mine looks a little too short. Nothing worth showing off tonight. I spent 20mins in the shed shaping/ losing weight and I'm just not happy yet. Much work on your chippy? What is the strengthening band Danny is speaking of? Does the model require it or was is something to keep the full size from splitting in two?

[Nev]

I think your on the right lines but yes the vey end looks a bit stubby, no criticism intended, a bit more tapered and maybe a tad longer would look more like the photos.

I haven't been doing much, just messing with the cockpit fitting so absolutely nothing to show. The model Chippy doesn't need the band but is quite prominent on the full size, so as far as detailing goes it's the be bare minimum. Danny, as I'm sure you know goes a lot further and is trying to encourage us to have a go at including some of the scale details.

Keep sanding and shaping and you'll get there.

Nev.

[G-JIMG]

Shane,

There is a useful Rudder mod that helps protects it in the event of nose overs. It introduces thin sheet carbon fibre to specific areas.

[Shane Sunday]

Hey Nev, G-Jimg. I've only just discovered micro balloons and WOW that stuff really works when mixed with epoxy. I've extended the tail section by adding some balsa then filled in with micro balloons and sanded to shape. I've no photos at the moment to show for it and I know I've not updated recently but we've been building a coffee shop here and this takes all my spare time. Funny enough I've managed to utilize much of my model building experiences.

On a model flying note. I've managed to fly my little mustang I've been building. We don't normally get good weather for flying this time of year but we had a cracker sunday just pass. A fellow and I at the field decided to mix it up and it was IC against veggie power. My little mustang is way more nimble than his high wing sportster with a 52 engine. Although he had tones more power I could out turn him. Also Another fellow at our club has a cold war prototype bomber in EDF. This model is so bloody light and he's been fly durration on a 4 cell 3000mah 25c lipo. around 40 inch wing span and he made it to 23 mins!!!!!!!!

more build pics and updates in a couple weeks

[Shane Sunday]

here is the helium filled EDF model. Not a very good shot as it was high up and shot from my phone.

and here is the wee Mustang I've been working on and flying when the weather gives me a chance.

sorry the shot is tiny. My phone uploads picks whichever way it likes and in order to show this one I had to flip it.

More soon.

[Shane Sunday]

Hey folks. Last post was back in January. boy is this build trudging along. But I'm back at it again expect to see some new photos soon. THis thing will get done yet!

[Shane Sunday]

As promised. It's been quiet the past few days and I've got some work done. I had decided ithat micro ballons was the way forward and a tub of the stuff cost me 15 quid for a fair amount. I then mixed up west systems slow cure epoxy and microbaloons to get a thick paste, lay cling film ontop of the wing, attach the fuselage and squeesed the paste in between the wing and the fuselage to close the gap on the wing seat. Sorry no photos.

I then went to work on the cowl. The plan has the shapes for the flaps on the cowl, which ive lost a few peices over the years with moving. So witht the remaining few I rumaged through my junk to find scraps of litho plate and cut out some more. Using CA to afix to the cowl I managed to glue thumb and forefinger to it as well. That slowed things down. But this time I followed intruction better and used a glass cloth and epoxy bandage to weld everything in place. I seem to have learned with age.

im covering this model with LITESPAN. Its light, paintable, light and I have a bunch of It. Unfortunately its red. But iit's paintable. And im noth the greatest at covering. Its also a slow process due to the fact you have to put balsa lock down first as well as on any over lapping peices as well. Which requires 15 mins to dry. So forward planing is a must with this stuff.

[Shane Sunday]

been puttering along here and there. Turns out I don't have enough litespan to cover the fuselage. Waiting on delivery. While ivd been waiting I've tried to sort a way to mount the cowl. I made 3 brackets from aluminium, epoxied hard balsa to each peice and soaked them with CA. Getting the right nose length that looked good was tough. Lots of eyballing.

Side shot

Ive also aded a bit of trength to the vert stab befor covering. Now waiting on that lite span

[Shane Sunday]

Well the lite span showed up and I've been working away. Covering is time consuming and a PINA! I've also located my fake radial. I thought I'd lost it.

[Shane Sunday]

Hey guys. I've been wanting to start painting this bird but t just needed some details. Like I've said before this is going to be stand off scale but I still wanted to add a little something. I didn't want to go through all the work of building up panel lines the way some of the great master builders do it. I've never tried it and I know i'd botch it up. So my idea is to use Ducting tape. It's a very sticky foil tape that is thin and light. So I needed a drag knife for the CNC machine which I made on the lathe. It's simple enough. The factory bought ones are £100 plus and mine cost me £7.00 the cost of new blades. Basically it's an aluminium bar milled to shape with a 2mm hole drilled to accept the blade then a 6mm hole drilled to accept a magnet and spring with an end cap. I milled this last bit too much therefore the black tape. Lastly an O ring just to snug everything up. Once I'd got the cutting depth sorted I redrew the details in illustrator and sent it to the machine to cut. Works a treat.

sorry the images are on their sides.

[Trevor Rushton]

Shane I am following your progress with interest; my building has dropped off a bit of late due to work pressures but I did try making my own dragknife; it was a variation on the Donek theme and whilst I was pleased with the way it looked it was a total failure. I also have a Stepcraft and am keen to expand its capabilities.

You would not happen to have a rough sketch of your design that you could share wold you? I am keen to have another go.

Many thanks

[Shane Sunday]

Hey There Trevor. I can see there are people watching but the odd comment helps to keep interest. So thank you good sir. The drag knife is pretty simple but needed the use of a lathe. Rather than ue the main hole on the stepcraft machine I built the knife to fit the smaller hole on the caraige. I can draw up a sketch and post it here soon. The trickiest part has been getting the cutting depth set just right. I use depron as a sacrifice layer and tape my material down to it. This helps to keep the blade sharpe. I also slow the machine down to 20%. I'm still working on it little by little but each new invention takes time from actually building and doing. Aw well once this tool is sorted it'll help with all future builds.

Thanks for looking in

[Trevor Rushton]

Thanks Shane; re the cutter no hurry. The Stepcraft cutter seems to be spring loaded so that you set the depth of cut (blade projection) and then the Z axis puts the compression on the spring. I have a lathe (not that I am very good with it). I have also been experimenting with 3d printing so I quite fancy having a go at something.

I am intrigued by the use of depron ribs on your Corsair; I have been tempted to try it on a couple of builds but they have not progressed beyond initial trial stage. I was nervous about the strength, but this was an open structure rather than a sheeted one. Would you do it again?

[Shane Sunday]

Depron built wings are great. Ive built 4 maybe five wings using depron ribs and sheeted with depron then glassed. They are all brilliant. Lessons learnt though... you're going to need some ply ribs if you're going to have undercaraige. Otherwise build the same as a built up structure. So yeah I plan on building more and more models this way. Also im just a beginner on the lathe too. I'll get you a drawing and you'll see just how simple it really is.

[Shane Sunday]

heres a rough drawing of the drag knife. I hope it helps

[Trevor Rushton]

Thanks Shane; thats great: I'd not thought about using the small hole - that's too simple! I will have a go at it at the weekend - I have ordered some blades and will see how it goes. My larger Stanley knife version was a disaster but it taught me how to cut 6mm aluminium on the Stepcraft. (Slowly!) I think that I have been overthinking the design.

I'll look at the depron ribs again; looks promising. Thanks for your comments I am also thinking of using it for some (not all) fuselage formers.

[Shane Sunday]

You were able to cut aluminium with a stanley? Wow that is dedication or is it pig headedness. Haha. I built my BT mustang using mostly depron. It flies really well. Electriflier on these forums has some great ideas for building with depron. What he does with the stuff is like magic. I had considered rebuilding the corsair from depron but I'm a bit pigheaded and don't like to throw stuff away.

Regarding the drag knife. I wrapped some thin piano wire around a drill bit to make my spring. I think I could cut a turn or two off of it in order to allow the knife a little more give. So far I've found cutting "ducting tape" the depth is best at .12 to .15. Cutting speed reduced to 10.

WHat controller are you using? I've got UCCNC.

Best of luck with it. Takes a bit of fiddling but it does work. Next I'm gonna try cutting some solar film. that stuff is thin!

[Trevor Rushton]

Ha, visions of cutitng alu with a Stanley knife - I wish! No, my post was unclear; I was making a blade holder to take a Stanley Knife blade. The holder fitted to a spindle and the spindle fitted into a couple of bearings like a Donek knife.. It took me 4 failed attempts to cut it out with a 3mm dia cutter on the Stepcraft (and loads of cutting oil). I don't think that I will rush to do it again!

I do have some Vance Mosher plans for a large Firefly - its over 7kg if built in Balsa, but a composite Depron/balsa version could be good fun. I would like to find a reliable way of turning hard copies into vector drawings for the Stepcraft; my attempts at auto tracing and conversion have not been rewarding and I have not been happy with their quality. So far I have resorted to redesigning using DevFus and DevWing

I am using Cut2d and UCCNC.

Sorry, this is taking the thread a bit off topic so I'd better let you crack on with the Corsair!

[Shane Sunday]

Hey Trevor it's good to learn and try new stuff. On the topic of redrawing plans, I use Illustrator. The pen tool is your friend. I'll scan the plans in photoshop, this takes many scans but can be done with excellent results. I line them back up in photoshop and once I'm happy I'll flatten the image and just click and drag it into illustrator. I lock the layer the plan is on and create a new layer to draw upon. I'll use a different colour so I can see what the hell I'm doing.

Tip: replicating any part of the drawing is as simple as click hold ALT and drag.

Tip: Curved edges, using the pen tool click and drag and release when you're happy with the shape.

All programs that are new to us are daunting to start but just hold the mouse over a particular tool and a pop up will tell you what it is. Then just play with it see how it goes.

Tip: Command or CTRL Z. Your best friend. Just undo your mistakes then try again.

Really the pen tool in any drawing program is the main tool. Learn it and there will be no plan you can't recreate.

Boy. What a day! I thought I was going to start painting today as I had it off work but nooooooo! In order to complete the stickers to any form of satisfaction I had to level the bed on my stepcraft machine. I knew it was off a touch but after taking it apart I found that the factory had botched up the bed. It was like a rolling ocean! Anyway I got that done then went back to cutting alluminium foil tape. This was tricky as I needed much wider foil than I had so I used Vinyl transfer tape to stick 2 pieces of foil tape side by side to gain the width needed. Also it seems the best way to affix this to the bed is UHU por or some sticky glue. Otherwise it just snags and ruins your work. Like 6 or seven time before you smarten up and do it right. Then you need to use a knife to pick all the stuff you don't want off the cut. Finally use more Vinyl transfer tape to lift your stickers off the bed and place them onto your model.

It's not perfect but it's better than nothing on there. And it'll show up through the paint.

And this one

This has been so much work BuT I think I've got it down to a science now. A few more things to cut out and add before paint don't plan on going crazy though.

[Trevor Rushton]

Hi Shane - its coming on and looking good. I am usually very impatient by this stage and cannot wait to get the primer on to see what the panels and bits look like.A bit of care at this stage makes a big difference and worth the number of failed cutting exercises when its finished. A few rivets perhaps? I have used glue and also the Mick Reeves rivet tapes before and very much like the latter albeit they can be a bit fiddly. Once you have used the cut rivets you can use the tape as a template for more. The real challenge would be to use the vinyl cutter to make some.

You mention that you have glassed the wings - did you use Poly C or resin? Presumably doing this also lets you use cellulose based spray paint or rattle cans? I have had good results with both methods although PolyC on to foam veneered wings was less satisfactory as it caused a degree of rippling.

Thanks for the Illustrator tips - I have kept away from that type of graphic programme up until now preferring to fight it out with Cad, but I will certainly give Illustrator a go.Thinking about it I have a cheap Serif graphics programme - I will have a look and see if that has a similar feature.

Bed levelling on the Stepcraft is a bit of an issue. I realised that I had a problem when I was cutting out the aluminium for my blade holder; I was making very light passes and realised that the first few were making contact but running out to zero over about 75mm. Not quite sure how to deal with it; having spent ages getting the x and y axis to work properly I am reluctant to take it to bits again. It seems that the favoured approach is to put a heavier and better supported bed in place - that seems to be quite a lot of effort. Did you have a magic trick? It's a great machine and I am very pleased with it,so this is not really a big issue for the uses that I put it to. However vinyl cutting would be a challenge I think. Fancy getting the laser cutting head?

[Shane Sunday]

Hey Trevor like you I too get very impatient at this point and yes I went straight into paint. I was unsure what I wanted to paint her but I knew I didn't wan the same as the big one I have still in the box upstairs. So I searched and searched and finally I think I've decided on either #530 0r #13 both have checkered cowl but 530 has a checkered rudder as well. I do like that #13 has NAVY lettering on her too so still undecided.

 

When I'm doing a built up structure like this I like to use west systems epoxy and I use 45grm cloth on the bottom with 25grm cloth on the top. I've used PolyC on lots of foam models but I feel this needs the trength and durability epoxy affords. While I have airbrushes for the details nothing beats a rattle can from the automotive shop for shear coverage.

I had thought about getting the laser but I'm waiting for something just a bit more powerful for the machine. A 2watt laser will go through 3mm balsa in about 5 passes and just forget ply. It would be great on depron but I have the hotwire cutting attachment for that and it's sweet. Not to mention a hell of a lot cheaper.

here's a shot of how the corsair sits for now. There's lots more to do but sure it'll get there soon enough. Maybe she'll be up and flying by january when it's balmy and warm here.

Edited By Shane Sunday on 26/11/2017 19:15:30