Colin Leighfield Posted September 24, 2016 Author Share Posted September 24, 2016 Simon, not sure about "impressive" it's very much in my "codge it as you go along category"! I'll make sure that the air does its' job and is dissipated in the most positive way that I can devise. It's going to be very draughty inside the fus! Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 25, 2016 Author Share Posted September 25, 2016 I'm going to make all of the chunky bits and then do the final sanding to shape at the end. I've made the front top piece that includes the cockpit and will be the hatch for the battery access, using 1/16" balsa and 6mm grey Depron. I've used 2mm aero quality Depron for the cockpit "floor". I can't recess that very far because of needing space for the battery. I then made a start on the tailplane/elevators, using 2mm aero quality Depron for top and bottom skins and 3/16" balsa for the framework. Can't do much more now because we're off to Spain for 16 days, but I'm taking the plan with me and will draw up the modifications for the wing, including the Depron substitution for wood and also the retract detail. The size of the cockpit determines the size of the pilot you can fit inside it. On that basis it' something like 1/9 or 1/10 scale! As a warbird that puts it around the scale of a Skyraider or similar ground attack type. Interesting. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted September 25, 2016 Share Posted September 25, 2016 I seem to remember that my pilot from Real Pilots was about 1/9th scale. It is surprisinghow big some jets are. Even in my day Javelins and Lightnings were big aircraft. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 25, 2016 Author Share Posted September 25, 2016 They certainly were Peter. To me the SM is definitely a warbird and I think I will probably finish it in that style, with a military style pilot. I'm Looking forward to finishing and flying it. The only problem I don't have an answer for at present is the lack of suitable spinners for the contra-props. I can put a spinner on the front one, but the rear prop is a problem. I'll think of something eventually. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted September 25, 2016 Share Posted September 25, 2016 Yes, I agree that it is a warbird. I was really doing mine in aerobatic team type colours. I could see that the spinner might be a problem. Any chance of fitting a spinner back plate from the old two part type spinner? You see them sometimes on Ebay. and I think someone still makes them Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted September 25, 2016 Author Share Posted September 25, 2016 That might work, I need to look carefully at it. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 13, 2016 Author Share Posted October 13, 2016 We got home yesterday, but I've been working today and just managed to get an hour in the shed tonight. Although the plan suggests moulding the canopy from a pop bottle, there is one available from Hobbystore, so I've got one and here it is untrimmed. I've finished the tailplane, although I haven't cut the elevators yet. I've just started on the fin and that is using the same Depron/balsa composite as the tailplane. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 14, 2016 Share Posted October 14, 2016 They have done a nice job of that moulding. Obviously improved the pattern that I sent in. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 14, 2016 Author Share Posted October 14, 2016 Peter, yes, I'm pleased with it. I don't mind having a go with the pop bottle, but I wouldn't do as good a job as this. As soon as the fin and rudder are done (I'm hoping tonight), I'll start on the wing. Positioning the retracts more or less in line with the plan position, working inwards. To get the wheels in the down position exactly where you show them, as well as getting them neatly into the wing, it looks as if the best way will be a pintle angle of three degrees and a forward bend in the legs about a third of the way down. That will also give a bit of spring on landing and reduce the load at the point where the legs enters the retract units. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 14, 2016 Share Posted October 14, 2016 That could be an interesting operation. At least with the wing shape it should be a bit easier. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 14, 2016 Author Share Posted October 14, 2016 It's pretty straight forward Peter. As I want the wheels in the down position to be exactly in the same position as you decided, i.e slightly forward of the l.e, the retracts needed to be raked back slightly to get the retracted wheels into the centre section behind the l.e. Bending the legs makes that much easier, otherwise the pintle angle would need to be a lot more than three degrees. Otherwise I could set the retracts up straight, but then the wheels would go in at an angle to the horizontal. I juggled with the options while I was away and this looks like the most practical solution. Setting the wheels so that they are behind the l.e in the down position makes it dead easy, but I don't want this one nosing over on landing. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted October 14, 2016 Share Posted October 14, 2016 It's a fascinating conversion Colin. Can I ask what glue you use for the foam to balsa joints? Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 14, 2016 Author Share Posted October 14, 2016 Hi John. At the moment Deluxe Materials Foam Free, it sticks Depron to balsa excellently. It costs more than Por, but I like it. I've used Por perfectly well for the same purpose, although I did have that experience earlier in the thread when I used it for attaching the 1/64" ply doublers to the fuselage sides and it attacked the Depron in places. It was a total surprise, but it shows it can happen. It seemed to be a function of a large area, perhaps with a limited air supply delaying setting for a long time. I'd joined them wet to allow for some sliding into position, I don't think it would have happened if I'd used the normal dry contact method. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 14, 2016 Author Share Posted October 14, 2016 Back in the shed. Just found out that Uhu Hart balsa cement doesn't attack aero quality Depron, it sticks it beautifully. It attacks the ordinary grey stuff though. Edited By Colin Leighfield on 14/10/2016 21:03:04 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 14, 2016 Author Share Posted October 14, 2016 Sorry, clicked twice. Edited By Colin Leighfield on 14/10/2016 21:07:29 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 14, 2016 Author Share Posted October 14, 2016 I finished off the fin, noticed afterwards that in a couple of small areas there was some attack on the aero quality Depron from the balsa cement, similar to the experience with the Por mentioned earlier. Not much and you can see where I've used some filler. I've used 5mm carbon fibre tube epoxied in place as dowels to locate the fin. Just started on the rudder. I had a long day at work today so could only do a bit this evening, should get a lot more done this weekend, hopefully including work on the wing. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 18, 2016 Author Share Posted October 18, 2016 As usual things get in the way and limit shed time but I've managed to do a bit more, completed the rudder and started to look at the undercarriage detail before I start on the wing. These are from HK and are designed for a model weight of 2kgs, i.e. 4.4lbs. As Peter describes a weight of 5.25 lbs, this makes weight reduction essential and gives me a target. As the undercarriage legs are very short, reducing inertia for retraction and bending loads on the pivots, I'm hoping to get away with it. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted October 18, 2016 Share Posted October 18, 2016 Colin Looks good. A weight of even 4.4 lbs would scare me with Depron. As far as I know dry balsa glue (after 24 hours?) is completely inert to Depron I can only assume the balsa glue was not quite dry when it attacked the Depron which of course it does with 'gusto'! Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 18, 2016 Share Posted October 18, 2016 I did get some slightly larger legs from HK for a heavier model buthaven't used them yet...Another project got in the way. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 18, 2016 Author Share Posted October 18, 2016 Hi Simon! I'm always a bit conservative in my estimates! I hope to do a lot better than 4.4 lbs, particularly as I want to fly it on 375 Watts. We'll see. Peter, I'm hoping these legs will do it. If the weight comes out comfortably within 4lbs. all in, it should be fine. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 18, 2016 Share Posted October 18, 2016 Well she does really nice greaser landings so should not stress the gear very much Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 19, 2016 Author Share Posted October 19, 2016 I'm sure you're right Peter, I'm really looking forward to finishing and flying this. I'm very surprised that we haven't seen more being built through the forum. It would be nice to see a few more, I/C or electric, built exactly to the plan or with a bit of extemporisation! Perhaps we will. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 19, 2016 Share Posted October 19, 2016 Yes, I did expect one or two more. Wait till you se my new build. Somehow I don't think there will be too many of them. and unless you can vac form depron none of them Started the album called Destiny. Edited By Peter Miller on 19/10/2016 19:43:23 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 19, 2016 Author Share Posted October 19, 2016 I can't wait to see what this is! Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 20, 2016 Share Posted October 20, 2016 The drawings are in the album mentioed above. Just photos of the drawings. Quote Link to comment Share on other sites More sharing options...
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