Tim Hooper Posted February 25, 2012 Share Posted February 25, 2012 Have a peek at the YouTube video, and tell me that this isn't a spectacular little aeroplane...... Speedtwin I first became aware of this lovely 26' craft due to a posting on this very forum, and it soon earned a place on my 'to do' list! Searching the net revealed lots of photos, but no 3-view. As the ST2 is currently in production, it made sense to contact Speedtwin Developments themselves. I talked to their very helpful MD, Malcolm Ducker, and explained the situation in order to gain his permission to emulate his product in balsa at 1/7 scale. Despite not having a suitable 3-view, Malcolm has furnished me with the general dimensions, and I've run a ruler over the photographs and come up with the following outlines; (That little Turnigy outrunner looks lost in the nacelle, doesn't it?) Profili software has generated a set of aerofoils. I've plumped for a 12% E207 section - a semi-symmetrical profile to give good aerobatic performance. Rapid Models has supplied me with twin Turnigy powertrains, and four metal-geared servos. I've got lots of head-scratching and pencil work to do before I start to cut balsa, it's true, but starting the build thread this early is a major motivator for me. Anybody fancy one of their own? 45" span, 400 watts total from a 3S pack. tim Edited By Tim Hooper on 25/02/2012 21:07:52 Edited By Steve Hargreaves - Moderator on 14/03/2012 08:55:58 Quote Link to comment Share on other sites More sharing options...
Stefan Hafner Posted February 25, 2012 Share Posted February 25, 2012 At that size you won't be replicating little mini rudders under the fuselage then?? Should be a cracker though Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted February 25, 2012 Author Share Posted February 25, 2012 Stefan, They certainly won't be functional, that's for sure! I gather that they're remote aerodynamic balances for the ailerons. tim Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 25, 2012 Share Posted February 25, 2012 should be good to follow along, nice one Tim Cheers Danny Quote Link to comment Share on other sites More sharing options...
Nev Posted February 25, 2012 Share Posted February 25, 2012 Always fancied having a go at a twin, this looks perfect. Very interested in this one Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted February 25, 2012 Share Posted February 25, 2012 yeah i like the look of that myself. Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted February 25, 2012 Author Share Posted February 25, 2012 Thanks guys! I should just point out that Rapid Models are not sponsoring me with motors etc. To answer a query just made, I pay full retail price for their products and use them as I see fit. tim Quote Link to comment Share on other sites More sharing options...
Seamus O'Leprosy Posted February 25, 2012 Share Posted February 25, 2012 I would prefer something arounf the 65" span Quote Link to comment Share on other sites More sharing options...
Ton van Munsteren Posted February 26, 2012 Share Posted February 26, 2012 Tim, Nice will make a lovely model with good flight performance. Seeing it made me at first think that they would have done a scaled up version of one of your models which was not yet published. Great vdo looks like the Pilot is having fun throwing it around and doing those passes. What is the motor type that you selected and for what prop, is that the equal to a Typhoon 15/10. Ton Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted February 26, 2012 Author Share Posted February 26, 2012 Posted by Seamus O'Leprosy on 25/02/2012 22:13:08: I would prefer something arounf the 65" span No problem Seamus. All you need is a big, blank sheet of paper, a ruler, a pencil - and away you go! Ton, Thanks for the comments! I did consider a pair of Typhoon 15/10's but the price was prohibitive, so opted for Turnigy D2826/10 1400kv units with matching Plush 25A ESCs. Quote Link to comment Share on other sites More sharing options...
Ton van Munsteren Posted February 26, 2012 Share Posted February 26, 2012 Nice motor Tim did read that it should do well on an 8x3,8 APC it pulls 650 gramms at 12.5 Amps. Ton Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted February 27, 2012 Author Share Posted February 27, 2012 Ton, The specs say around 200watts on a 7x4 prop, but I can always experiment a bit, can't I? More drawing this morning, with the ribs drawn in, and the tail surfaces fleshed out with their internal structure. tim Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Just adding a post so I can follow along......this Tim Hooper bloke seems to know what he's doing so it should make a nice model..... Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted March 5, 2012 Author Share Posted March 5, 2012 With the plans all fleshed-out..... ......it seems appropriate to start hacking some balsa into shape! I don't have enough 1/16 sheet to do my usual thing and attack the wings first, but I do have enough 1/32 sheet, so on with the tail surfaces instaed! Edit to correct picture spacing... Edited By Steve Hargreaves - Moderator on 26/03/2012 12:35:20 Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted March 5, 2012 Share Posted March 5, 2012 you dont hang about do you. Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted March 5, 2012 Author Share Posted March 5, 2012 Posted by Tony B on 05/03/2012 21:42:29: you dont hang about do you. Actually, if the truth be known, I've felt rather guilty that I haven't been able to make quicker progress! tim Quote Link to comment Share on other sites More sharing options...
Olly P Posted March 6, 2012 Share Posted March 6, 2012 ahh...The list is already too long for my money, time and ability! Tim you're a pain with these nice, well designed models you keep doing! Quote Link to comment Share on other sites More sharing options...
Adrian Day Posted March 7, 2012 Share Posted March 7, 2012 following this one for sure looking good so far Tim don't take you long once you get your hands on a design.. how do you work out the dimensions to put it on a plan is there certain points that you work from.. to the the scale..?? Top marks so far will keep looking Regards Adrian Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted March 7, 2012 Author Share Posted March 7, 2012 Adrian, It's pretty labour-intensive, especially when there's no 3-view available! I work from 2 critical dimensions - the span of the full-sized aeroplane, and the span of the proposed model, which gives me a scale to work to. The 26 feet span of the ST2 gives us a 1/7 scale 45" model. For the rest of the dimensions, I have to rely on photographs and do my best to work it out from there! There's a fair amount of artistic licence being ruthlessly exploited in this particular case...... tim Quote Link to comment Share on other sites More sharing options...
Seamus O'Leprosy Posted March 7, 2012 Share Posted March 7, 2012 Posted by Tim Hooper on 26/02/2012 18:11:51: Posted by Seamus O'Leprosy on 25/02/2012 22:13:08: I would prefer something arounf the 65" span No problem Seamus. All you need is a big, blank sheet of paper, a ruler, a pencil - and away you go!. What size ruler would you recommend and will a 3H pencil be ok? Quote Link to comment Share on other sites More sharing options...
Adrian Day Posted March 7, 2012 Share Posted March 7, 2012 Hi tim thanks for that info i have been trying to work out a design, looking at your design its a working art , its really not simple .. as people make it look .. i was working from a drawing (3view) of a pilatus pc21 i was working on the idea of multiplying the picture till i got a working size wingspan Kind of if say the picture was 4 inch wings span then i would multiply it by 10 giving me my 40" then every dimension i take do the same .. dont know if this works.. i take my hat off to you for this model it does look a very hard one to work with ..like the idea of artistic licence , i did the same when designing my cub made some changes to make it my own.. just wish i could work out how to use devcad or something like that to do the wings i cant seem to get the rib shape.. for my edge or my cub ... dont know how you do it .. Regards Adrian Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted March 8, 2012 Author Share Posted March 8, 2012 Posted by Seamus O'Leprosy on 07/03/2012 22:09:24: What size ruler would you recommend and will a 3H pencil be ok? Ah, if only life were that simple, Seamus! In the same way that the newbie flier lusts after a totally unsuitable Spitfire, the acolyte designer yearns in vain for the fabled 3H racing-spec pencil, and is almost always disillusioned by the quirky and unpredictable handling of this coveted implement. I'd suggest you go for a more suitable designing tool to begin with; a stick to draw in the sand perhaps? Or maybe a piece of chalk on a slate substrate? Adrian, you've got it! Multiply every dimension by the same factor. It's as simple as that! tim Quote Link to comment Share on other sites More sharing options...
Adrian Day Posted March 8, 2012 Share Posted March 8, 2012 so im working in the right direction thats good to know well its back to the drawing board for me then.. how do you know what the ribs should look like when you do the builds Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted March 10, 2012 Author Share Posted March 10, 2012 Adrian, There's quite a few free aerofoil generators on the net, but I use a pay-program called Profili. Right then, a good day to today! Instead of messing about making individual wing skins, it seemed sensible to do them all as one sheet, so I edge-joined 9 pieces of 1/16 balsa together before cutting the two lower skins free. The rib and spar positions were drawn directly onto the balsa itself. The black item is the aileron servo trying it's future home out fo size! Netty cut out the wingribs, whilst I laid down the spars etc A closer view of the wing panel showing the shear webs. The root ribs will be added after the two panels are joined together. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted March 10, 2012 Share Posted March 10, 2012 you don't hang about do you Tim looks great Cheers Danny Quote Link to comment Share on other sites More sharing options...
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