Here is a list of all the postings Steve McLaren has made in our forums. Click on a thread name to jump to the thread.
|Thread: Folland Gnat Build|
After taking part in the Jet Provost mass build, and having attended the Great Orme event in June and discovered the thrill of
So I looked through all the model photos on the PSSA website for something that would catch my imagination. I didn’t want anything too big, too complex, or too expensive - mainly because I want to get into service as quickly as possible, but also because at my level of flying skill, it may not last all that long!
So, after some deliberation, I settled on the Folland Gnat, designed by Alan Hulme, and which was apparently available as a plan from MHS. Like the Jet Provost, the Gnat features in some of my earliest memories of air shows, and so for me, represents something a lost ‘golden age’ of wonder and amazement.
When the plan arrived, I studied it for several hours (as you do!). I was pleased to find that the construction looked quite conventional and simple (albeit with a foam cored wing which I haven’t done before, but which I have been prepared for since late last year when I built a cutting bow in preparation for another project which never got started – only to be replaced by the Jet Provost build). But the plan is quite the opposite of the Jet Provost plan in many ways. It’s an old hand drawn plan, and Mr Hulme was clearly no stickler for accuracy! It’s more of a ‘construction suggestion’ than a detailed plan. There’s hardly a single dimension which is consistent in any 2 views! Where he’s drawn complete formers, the shapes are quite asymmetric! So I’m going to have to be very careful, and sort of re-create a consistent geometry over the top of the original plan.
But, just like the Jet Provost plan, I realised it was impossible to tell what shape the fuselage was really supposed to be (particularly at the rear end) from just 2 views. So, I went out to town and bought the 1/72nd Airfix model to use as a reference.
Now, I must admit that when studying the photos of Alan Hulme’s model on the PSSA website, there was something about it which didn’t look quite right to me. On comparing the geometry of the plan with the airfix model it confirmed my suspicions. He’s designed it with absolutely huge wings! It really does look like a glider version of a Gnat! It turns out the plan is to 1/10th scale, and the wing span on the plan is 39 inches. By my simple scaling it looks like a true scale span would be 29 inches. So 10 extra inches in 29, or 34% oversized. I’ve sketched the true scale tip position on the plan in the photo below.
I’ve decided that I don’t want mine to look so obviously out-of-proportion, so I’m planning to split the difference and cut the span down to 34 inches, in the hope that it will still look like a Gnat. I’ll just have to build it as light as I can, and see how it works.
I ordered all the balsa from the balsa cabin, and I’ve a made a start on those wings.
First I had to set up a jig on my bench to allow me to make some straight and square cuts of the foam black which I had been saving since last year (and was really supposed to turn into some wings for an electric mosquito, but I’ll get round to that one day). I made the jig with a pair of 90 degree angle brackets screwed to 2 pieces of wood, which were then carefully shimmed to the bench and screwed down, to make 2 true uprights.
I then photocopied the 2 core templates provided on the plan, and carefully checked that they were still accurate to scale, before pasting them to a sheet of paxolin and cutting them out.
I first cut the foam block to the wing planform shape, then marked up the edges to define the positions of each core template. I decided to allow for just 1/8th inch of washout at the trailing edge of the tip (and not the 3/8ths suggested on the plan, and which seemed completely excessive to me – can that be right??).
I then set about cutting my first wing core. And I was quite pleased with result. So whilst I was on a roll, I moved the templates down the block a bit and cut the second one. They look alright to me (for a first attempt anyway).
Edited By Pete B - Moderator on 29/08/2014 12:06:23
|Thread: PSSA Gliding Events|
Here are my best shots.
|Thread: Andy's Partly-Retrospective PSS Jet Provost Build|
Very impressive Andy. That tail section looks so much better.
But I have a question! How do you cut away the already fitted film to an accurate line without risking cutting significantly into the balsa? When I have to do this I am always worried about weakening my structure, so I tend to peel first and then try to cut off the peeled bit. Doing this, I can't ever get an accurate shape. Do you have a clever method or is it just a case of taking great care with the blade over the depth of cut?
|Thread: Another PSS Jet Provost Build Blog|
After attending the event at the Great Orme over the weekend, I would like to finish off this blog by saying thankyou to a few people.
First and foremost to Phil for having the vision and the drive to put on this whole event, and for the hard work he put in to deliver it so successfully. It was a privilege to be a part of it at the weekend.
For me, as a first timer to these
It was a pleasure to witness some very impressive flying from many more of you. But the best bit was getting the chance to enjoy the shear exhilaration of
Thanks too to Andy Blackburn. Not just for designing such an enjoyable model to build and fly, but also for teaching me the basics of
I’m still a long way from being a comfortable
Thanks everybody. I’ll definitely be back.
I also meant to say, that when I next go to the slope, I will try your 'alternative' landing approaches. But I might practice with my phase 6 before I try again with the JP.
Thanks John. I'm building up the courage to have another go. I feel I need to be in a bit more control of my landings (well any control at all would be a start!) before I can turn up at the Great Orme. On the other hand, more practice means the risk of having no model to bring with me! A bit of dilemma!
So far, the new stickers are staying put, but thanks for the offer. I'll let you know if I need some.
Well I managed 3 flights today and she's still in one piece. But more through luck and the strength of Andy's design, than any skill on my part!
As I said at the beginning of this blog, I haven't done a lot of slope soaring and most of what i have done has been with gentle rudder and elevator models. I fly a few 4 channel electric powered models, but this is a bit different.
The forecast today was 16 mph southerly down here. But when I arrived at the edge of the slope it felt like at least 20!
I could hardly hold the model without it flipping backwards out of my hand!
It took me about 10 minutes to pluck up the courage to hurl it into the void. Miraculously it flew! It was all a bit wobbly at first and I came to the conclusion I was trying to fly it too slow. It tended to keep dropping a wing. But after quite a few clicks of down trim it was zipping about the sky quite nicely.
Then I made the mistake of trying a turn towards the hill. Although i pulled full up elevator, I just didn't seem to have enough control, and she struck the hill with a glancing blow. The tip tanks flew off, but she was otherwise unscathed.
I had 2 more flights, one of them about 15 minutes long in which I started to relax a bit, but they both ended the same way. Each time i decided to try a landing approach, and turned towards the hill, she seemed to lose a lot of height and I couldn't pull her out in time. So 3 terrible bounced crash landings and there's not a mark on her!
At that point I decided my luck wouldn't last forever, and I should either try a less windy day or seek some advice! If I don't get to try again before the Great Orme event, I shall be watching carefully there to see how it's supposed to be done.
It is a beautiful model in the air. She looks fantastic on those fast passes. I'm just hoping to get to the stage where I can relax enough to enjoy it!
No photos I'm afraid, as I was on my own, and my hands were full.
My homemade paper stickers turned out not to be a very good idea. 3 days later, I found they had peeled themselves off!
I guess the glue was just not sticky enough?
So I ordered some inkjet printable vinyl on ebay. It was only available in clear, but it seems to work. After printing, I stuck the clear vinyl decal onto a piece of white solartrim, then stuck another piece of clear vinyl over the top to make the whole thing waterproof. Then cut out and apply to model. They're a bit thick, but this time they seem to be staying on!
Today I finished my aileron linkages, and set up the transmitter programming. Then the final operation was to get it balanced. It needed a whole ounce of lead in the front of the battery box. I was a bit disappointed with this, having tried very hard to build the tail end as lightly as possible. So the total flying weight will be 26.8oz.
The forecast looks good for tomorrow, so I think I'll go give it a try!
This weekend I did the roundels and the lettering. I decided to make my own from solartrim - partly to save a few quid but also because I hadn't done this before and wanted to find out how easy/difficult it would be.
Well, in the end, it's not too difficult, but it does take a lot of time! And the little letters are sort of fiddly!
I printed the 2 complex decals (the 'danger - ejection seat' triangle, and the 'rescue' arrow) onto self adhesive sticker paper using my inkjet printer, and then gave tham a few coats of spray acrylic varnish before cutting them out and sticking them on. I'm not sure how long they'll last, but I can always do it again if they come off in the rain. In fact I printed a bit of a stock!
It's looking finished but I've still got to glue the fin to the fuselage, and set up the aileron linkages. But the 1st flight is getting close!
Today I finished all the major covering. Now just the details to do. And the assembly of course - this is still just a set of loose parts!
Having been shamed by Phil's work rate, I did make a little progress yesterday. I painted the black anti-dazzle patch on the nose, and added a few lines on the canopy.
You can see that I got a bit of a furry edge on the black panel. I've never used Prymol before, but I think it tends to dissolve the adhesive on the edge of the masking tape? The furry edge seems to be as much adhesive residue as it is paint. Perhaps there's a more resistant form of masking tape?
BTW what sort of pen do people use for panel line on solarfilm? I've used a Staedtler Lumocolour permanent marker, but i'm already noticing that sweaty fingers will smudge it, or wipe it off all together. Is there a better alternative?
|Thread: Phil's PSS Jet Provost - Build Blog|
Impressive work rate Phil, and you've still got time for reporting!
On Saturday I didn't think you had a hope of completing in time for this weekend, but now it looks like you might make it.
How are you planning to do all the lettering and decals?
|Thread: Another PSS Jet Provost Build Blog|
Thanks Peter for the alternative method. I'm glad it's not just me that finds it difficult.
I guess your step 5 is the key one. I never thought to do it that way, but I can see how it would work. You must need to be pretty careful and accurate with the scalpel, but if you iron the film close up to the line I can see that you would get a smooth and reliable shape. I'll have to try to remember that in case I ever have to do it again.
Are you going to go for the red,white and grey scheme on your JP? I'm not going to make it for this weekend, but maybe we can compare results on the 1st June?
I might go and tackle the canopy lines now.
I can't see me being finished in time for next weekend. Also, even if I was I'm not sure that the Orme would be my first choice for a maiden flight!
I spent today working on the fuselage covering. This model is certainly the most difficult I've ever tried to cover with film! After all that sculpting, there's not a flat surface or a straight line to be seen anywhere!
I decided to do each side with 3 pieces of white and then 3 pieces of red, to try to keep it manageable. This means I've got some overlap joints which (because of the slight transparency of solarfilm) show up a bit, but I'm hoping that the detailed markings will distract from that.
The most difficult bit for me was creating the curve in the red at the nose. After the covering the top half of the fuselage with the white, and after revering to various photos and drawings (including Andy's original model pictures), I drew a line on one side of the fuselage on the white solarfilm with a permanent marker. When I was happy with this, I created a matching template using tracing paper. But even this is not easy. The line on the fuselage is on a complex 3D surface. Transferring this to a 2D piece of tracing paper is somewhat approximate! But at least then I had something which should give me the same shape each side.
I then cut out two opposite shapes for each side from the film. I made them about 20mm deep at the nose and about 50mm deep at their rear end (about level with the back of the canopy). I stretched them a bit as I fitted them against the marker line, and then ironed the edge down. Then tried to stretch and iron the remainder down to the fuselage sides. I then covered the bottom of the nose with another piece - stretching to get it to fit the curvature, until it met the upper pieces. But it didn't go perfectly. I picked up a few wrinkles here and there - so I just had to iron them down hard! I reckon I could try this a dozen times and I'll always end up with the odd wrinkle! So it will have to do.
Also, after I though i'd finished, I looked at it from the nose, and decided it wasn't symetrical! So I cut another 10mm strip from the same template and went over the top edge of one side again. So I've got a lot of overlap joints, and it all looks a bit patchy. But that's probably the best I can do.
I'll be interested to hear how everyone else gets on with the covering.
A couple of weeks seem to have gone by and I've done nothing. But today I found a bit of time to carry on with the covering.
I thought I'd concentrate on the fiddly bits around the tailplane. The parts are all loose but I put them all together again to see how it was looking.
Since it's supposed to rain tomorrow, I should be able to find time to start on the fuselage itself.
During the week I painted the cockpit area and glued the canopy in place. I sealed the balsa inside the canopy with a coat of acrylic varnish and then applied a single coat of acrylic matt black ( with a bit of grey for the seat cushions - not sure if that's accurate, but it all looked a bit dull in one colour!)
I used a thin slice of the instrument panel graphic supplied by Phil Cooke, and printed on my inkjet printer, pasted on with PVA. The traplet canopies have a bit of a texture so nobody's going to be able to see it too well. Anyway it gives the general impression of an instrument panel, which will do for me.
I used 'canopy glue' to attach the canopy. I've used in on quite few models recently and it seems to work very well. My plan is to cover with solarfilm up to the edge of the edge of the canopy, and then use solartrim for the canopy lines and edges, and to cover the join.
Then I've been re-shaping my air intakes. I took a fair bit off the bottom edge, and had to narrow the under-wing fairing by about 1/4 inch each side. The result looks a lot closer to what's shown on the plan:-
So then I'm onto the covering. I've been playing around with iron temperatures a bit, before I started on the model itself. So I'm now using a cooler iron than might otherwise have done.
I have now started on some of the simple little pieces - the elevators using the grey (which is supershrink polyester). I've tried to set the iron at 100degC for the actual covering phase, but it varies a fair bit as the thermostat switches. But initial results look OK, and I would say the covering is easier with the slightly cooler iron. But will it avoid the wrinkling in the sun problem? Maybe I'll find on the 1st June?
Thanks Guys.It's not that neat really. I just choose my camera angles carefully and use an old 3MP camera so you can't see any detail!
And I don't usually build this quickly, but I want to have this flying by the 12th April. For that reason, and because I think my build is already carrying a few extra grams, I'm not going to bother with the rear wing fairings, nice though they certainly look Andy.
To answer Andy's question, it's 556g or 1lb 3.6oz, at this stage. But that's without any aileron servos or linkages, and without covering. My 2 servos will be another 30g or 1oz. And then the battery - In your flying notes you mention that the original used a 600MAh Nicad so that sounds like 4 x AAA size, or 54g (1.9oz). That would make it 640g or 22.5 oz +covering + however much balance mass I need.
I really don't have a feel for the weight of the covering, but it looks like it will be heavier than your original. But I'm still hoping for decent light wind performance!
On the covering topic - well for me it has to be the red, white and grey. That's how I remember them from when I was a kid, and that's what attracted me to this build in the first place. I'll see if I can find a reg number that isn't too common.
So yes, the ironing task is looming and I'm getting a bit nervous about that. It's all a bit more critical on a scale model., A lot of my other solarfilm covered models exhibit the wrinkling-in-the-sun problem, which Andy tells me is because I use the iron too hot. So I've got myself an iron thermometer ( the instructions which came with it also confirm the wrinkling due to iron being too hot theory) and I'm going to do a bit of research/practice before I start on the real thing. I ordered all the film a few weeks ago, but now I'm starting to doubt whether I've got the right shade of red!
Whilst thinking about the covering, I thought of another question for you Andy. You mention in the write-up that the matt black anti-dazzle panel was painted with enamel paint. Was that on top of the solarfilm, with a primer like Prymol? or did you fit the solarfilm around the black painted area?
|Thread: Just Possible Jet Provost by Steve|
I hadn't used laser cut parts before either and I too was surprised by how much carbon came off the burnt edges. But I wouldn't worry about it. - Nobody's going to see the inside and there's so much sanding to do on the outside that any fingerprints will be a distant memory!
|Thread: Another PSS Jet Provost Build Blog|
This weekend I've been working on the under-wing fairing - more sculpture! And there's not much on the plan to work from and not many useful photos on the internet either. After going through this phase:-
This is what I've ended up with:-
But it sounds like I'm not finished yet. My intakes are a bit fat at the bottom (based on expert advice) so there's a bit of re-modelling to be done.
Anyway I thought it was time I put the whole thing together again. It helps to keep me going (despite the balsa dust induced cough) when I can see what I'm aiming for!
So this is how the air intakes are currently looking.
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