JP2 Posted August 6, 2012 Share Posted August 6, 2012 Have to say mine is at about the same stage and I would really like a clear canopy as the model deserves some scale detail. Anyone making it commercially yet? On the subject of scale detail I have redesigned the undercarriage to make it look more scale like. Will post some photos in due course. Using top hinged ailerons as per a recent Rava I built, works well. Got the decals from Tim, really smart, JP2 Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted August 6, 2012 Author Share Posted August 6, 2012 Rex, I don't think that I've ever followed a plan 100%! There's always alternative ways of achieving a similar end, yes? So do whatever you're comfortable with. I don't think there's any doubt in that glasscloth will be heavier than film - no way around it. My method is to give the bare airframe a couple of coats of thinned dope to seal the surface, then use the lightest cloth you can, applied with WBPU (water based polyurethane). I use floor varnish from the local DIY superstore. A couple of thin coats will give a very tough finish, prior to the paint of your choice! JP2, I certainly haven't actioned a clear canopy, but I'm sure there's somthing out there somewhere... tim Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted August 6, 2012 Author Share Posted August 6, 2012 Oooops.....double post! tim Edited By Tim Hooper on 06/08/2012 21:45:25 Quote Link to comment Share on other sites More sharing options...
Rex Ashwell Posted August 6, 2012 Share Posted August 6, 2012 JP2, By "top hinged ailerons" I presume you are talking about some type of tape similar to Tim's use of sellotape. I'm also interested in your undercarriage redesign as I haven't started my u/c yet - looking forward to your photos. It's good to hear that someone else is building. Tim, Thanks for the advise on glassing. I've never tried the WBPU method but I have read about it and, as a life-long woodworker, I'm familiar with the material. I don't have any dope these days but I've used shellac as a sealer and that would be my choice again if I decide to go down the glassing track. I'll start on the canopy and post some details if it's successful. Rex Quote Link to comment Share on other sites More sharing options...
Rex Ashwell Posted August 7, 2012 Share Posted August 7, 2012 Hi Tim, Transparencies for the canopy are now complete and that was a LOT easier than planking. First job was to make a former - I used a piece of paulownia, which is similar to dense balsa, but any soft wood would do, or even foam glassed on the outside like your canopy. This was bandsawn, planed and sanded to shape, just eyeballed and finished with 100 grit sandpaper, then screwed to a piece of 3mm plywood the same shape as the canopy base. The ply stops the shrinking plastic from crushing the edge of the former if it's made from soft material. Cut one end off a 2.25 litre soft drink bottle and wedge the former inside using scrap pieces of wood then shrink the plastic bottle around the former with a heat gun. You can be pretty brutal here as the plastic will take lots of heat, just move the gun around to shrink the bottle evenly. Now either cut carefully around the edges of the former with a sharp knife or outline the edges with a marker pen, cut open the bottle from the back and cut out the canopy with scissors. The only problem I struck was that the biggest bottle I could find was too short, so I made the windscreen first, then the main canopy as a seperate piece, allowing a bit of an overlap at the windscreen frame. I think the result is okay. I've posted a few photos of the process in my album for anyone that's interested. If you've never tried this, give it a go. It's simple, quick (about 2 hours total for this one), cheap and effective. The first try may not be perfect, although mine was okay this time, but if you fail just get another empty bottle! Rex Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted August 7, 2012 Share Posted August 7, 2012 A laser/cnc pack of parts will be available soon. I'll give a mention here when they go on sale. Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted August 7, 2012 Author Share Posted August 7, 2012 Good work Rex! I've just been looking at your step-by-step pics in your album. How much does the surface texture of the former transfer itself to the inside of the moulding? tim Quote Link to comment Share on other sites More sharing options...
Rex Ashwell Posted August 7, 2012 Share Posted August 7, 2012 Hi Tim, The surface texture doesn't seem to be a problem at all and I assume this is because of the way the plastic shrinks around the former. The process is not like vacuum forming, where very soft material is sucked onto the surface and picks up every detail. Instead the plastic remains fairly rigid and just shrinks, so it's in tension all the time and I suppose it just bridges across the high points on a rough surface. You can only form across convex curves with this method so, while I could use it to make the forward nacelle/motor covers, it would not form into the air intakes. It's not the universal answer to making mouldings, but it's perfect for canopies. There is a lot of information on the web which Google will find for you. The designer of the Guppy glider talked about using boiling water to shrink the plastic and some others stick the lot in the oven, but I've found the heat gun to be really easy and it allows you to control the shrinking by concentrating the heat in areas which may need a little more. You do need to try to pack the former into the bottle as tight as you can and you'll notice that with the windscreen I've jammed some blocks under the front to tilt it up against the surface before shrinking. This is just the third canopy I've made and it's by far the biggest, so I'm quite happy with the method. Rex Quote Link to comment Share on other sites More sharing options...
Rex Ashwell Posted August 12, 2012 Share Posted August 12, 2012 Tim, As I'm getting close to making undercarriage parts, have you found 1.75 inch wheels big enough on grass and is 12 swg piano wire proving heavy enough for the legs? Bear in mind you probably make gentler touch downs than I sometimes do. Rex Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted August 13, 2012 Author Share Posted August 13, 2012 Rex, I'm happy with the wheels as they are - on our close-mown strip. Feel free to up-size them a tad to suit your own needs. Yes you could fit stiffer legs, but then more of the landing shocks would be transmitted directly to the airframe. There's no perfect solution, only compromises! tim Quote Link to comment Share on other sites More sharing options...
Rex Ashwell Posted August 23, 2012 Share Posted August 23, 2012 Hi Tim, Okay, I understand the rational with undercarriage stiffness - I was a bit worried about bending a leg and not being able to remove it for repair without cutting into the lower nacelle. I'll find a way to fit a removable panel. Progress is slow, for a variety of reasons, at the moment although I've finished the cockpit. Not too happy with the rather crude hand carved figures but I guess they could be worse. The transparency looks okay but I have discovered that the water based glue I used is reluctant to dry between the impervious surfaces of the two parts. Quote Link to comment Share on other sites More sharing options...
Roger Bird Posted September 2, 2012 Share Posted September 2, 2012 Any news on the CNC pack yet? Quote Link to comment Share on other sites More sharing options...
A.A. Barry Posted September 4, 2012 Share Posted September 4, 2012 I have the Fuz and rear feathers done so far ( 2 days building ), I thought the model was a bit small, so I enlarged it by 20%, which gives it a W/S of 53", going to fit slightly larger motors and some el cheapo small H/K electric retracts with 2"wheels and med. size servos. Wood sizes are much the same, except the Fuz doublers have been enlarged to full depth between F2 and 4, from 1/8 to 3./32 crossgrain, the tail parts have been covered with 1/16 instead of 1/32 and the inside frame from 1/2" wide to 5/8 " I have a couple of very large comercial canopies amoungst my assorted bits, so I will cut one down to fit the main cockpit area Some of the wing ribs are now 3/32 instead of 1/16, as for the spars, I have long lengths of 6mm hard wood which I may use, as the wing is still on paper, Wash out does not appear on the plan, have I missed something here??? More as build progresses A.A. Barry Edited By A.A. Barry on 04/09/2012 02:48:00 Edited By A.A. Barry on 04/09/2012 02:49:52 Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted September 4, 2012 Share Posted September 4, 2012 Posted by Roger Bird on 02/09/2012 23:11:37: Any news on the CNC pack yet? Yes, it's all now ready to go so should be on sale within a few days. That looks very nice Rex Edited By David Ashby - RCME on 04/09/2012 07:22:02 Quote Link to comment Share on other sites More sharing options...
Shaun Marshall Posted September 4, 2012 Share Posted September 4, 2012 hi just beginning to build 1 of these and have a couple of questions rather than covering with solrfilm etc would there be any detrement apart from extra wieght to covering in brown paper and painting would the props need to be contra rotating if so what would be the best way to achieve this as ive read lots of pros and cons for both contra rotatiing and normal and am totally confused last question how much is the cnc parts kit gonna be Quote Link to comment Share on other sites More sharing options...
A.A. Barry Posted September 4, 2012 Share Posted September 4, 2012 David are you doing cowls as well??? Barry Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted September 4, 2012 Share Posted September 4, 2012 No Barry, they'll remain built-up as per plan. Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted September 4, 2012 Share Posted September 4, 2012 Posted by Shaun Marshall on 04/09/2012 08:26:08: last question how much is the cnc parts kit gonna be Pricing isn't my decision Shaun but the plans service people will let me know, hopefully, within the next few days and I'll post a link. Quote Link to comment Share on other sites More sharing options...
Pete B Posted September 4, 2012 Share Posted September 4, 2012 Posted by Shaun Marshall on 04/09/2012 08:26:08: would the props need to be contra rotating if so what would be the best way to achieve this as ive read lots of pros and cons for both contra rotatiing and normal and am totally confused Assuming you have a similar electric setup to Tim's, you can get a counter-rotating, or pusher, prop in the Master Airscrew range, here from HK, Shaun. Easily used on an electric motor as you just reverse the direction of rotation. Having counter-rotating props nullifies the torque effect of having both turning in the same direction. Some great enhancements to an already nice model, Rex. I particularly like your nod to the follicly challenged........is that you in the rear seat? Pete Edited By Pete B on 04/09/2012 12:40:48 Quote Link to comment Share on other sites More sharing options...
Shaun Marshall Posted September 4, 2012 Share Posted September 4, 2012 hi pete yes im using the same motor setup as tim 1 last daft question as this is my first twin electric build looking from the front of the plane i assume the pusher prop goes on the left motor and the standard prop goes on the right motor Quote Link to comment Share on other sites More sharing options...
Pete B Posted September 4, 2012 Share Posted September 4, 2012 There are differing opinions on this, Shaun, but I would arrange it the other way, ie the conventional prop on the left motor and the pusher on the right. This means that the downgoing blade is nearer the fuselage in each case, which, unless anyone disagrees, is apparently more efficient in terms of airflow over the wing. It worked fine for me on my P-38....... Pete ps There are no daft questions.........you are seeking knowledge - and that's never a daft thing to do! Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted September 4, 2012 Share Posted September 4, 2012 I would agree with Pete the downward blade needs to be closest to the fuselage as the increased angle of attack of that downward blade when the nose is raised will be closer to the centre of gravity (longitudinal) and have less affect in single engined flight. This explains it at about 45 secs onwards. Interesting to note that opposite rudder will have to be reversed when you go from thrust to drag ie working engine idled to throttled up, hadn't considered that. Cheers Danny Edited By David Ashby - RCME on 04/09/2012 13:57:32 Quote Link to comment Share on other sites More sharing options...
Shaun Marshall Posted September 4, 2012 Share Posted September 4, 2012 hi pete thanks for the info i will swap them around when i get that far with the build Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted September 4, 2012 Author Share Posted September 4, 2012 Crumbs......this is all getting very complicated, and far beyond the comprehension of an old bludger like myself! Having flown the ST fo some time now, I've no desire to source and fit Counter props - it flies just fine as it is. I'm keen to see AA Barry's enlarged version though! tim Quote Link to comment Share on other sites More sharing options...
A.A. Barry Posted September 5, 2012 Share Posted September 5, 2012 Hi Tim, yea I only have the fuz done at this stage I'll post some pic's a little later, Wash out...???? BARRY Quote Link to comment Share on other sites More sharing options...
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