Jim Newberry - Nuviation Ltd. Posted July 7, 2016 Author Share Posted July 7, 2016 Thanks for the interest chaps. Piers, the servos are Hitec HS425BB for the rudder and elevator - mid range, standard size servos. The wing retention nuts are flanged inserts from Model Fixings. Ordinary T nuts would have worked just as well but I happened to have the inserts lying around doing nothing. The great advantage that the inserts have over T nuts is that they can be fitted without having to gain access to the back of whatever they are being fitted into as they are screwed in place with an allen key from the front. This picture should explain it all... Stumps - I must admit to being no expert when it comes to ic engines, having flown only electric models for a number of years, but from what little I know, a Laser 100 sounds about right. Dad's build has stalled over summer as he is off to France for most of it. I know he was thinking about fitting a 17cc petrol engine but hadn't come to any firm decision last time we spoke. I am thinking about building another one and fitting a four stroke ic engine, but if I get around to that it won't be for at least a year or so as I have too many projects vying for bench space as soon as the Tiger has flown! Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted July 7, 2016 Author Share Posted July 7, 2016 Well they say confession is good for the soul, so this evening I have to hold my hand up to an almighty screw up. I made and fitted the windscreen, stepped back to admire it and suddenly came to the realisation that it looked as though it had been done by a baboon. Who was drunk. And blind. I wasn't going to post any pictures of it but then I thought it might be worth it for comedy value if nothing else, and it will remind me to take more care next time. So here it is... And a little closer.... Shockingly awful. Stupid boy. Thankfully, it came off quite easily and so tomorrow I will do a proper job, probably making it in three pieces with a decent frame. In happier news, I am quite pleased with the headrest and instrument panel I made.... 1 Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted July 7, 2016 Author Share Posted July 7, 2016 I've been looking into this a bit and, while I reckon the power would be fine, one problem I can foresee is that the Laser 100 is 135mm from the rear of the carburettor to the rear face of the propellor, while the distance from F1 to the rear of the prop on my Tiger is only 90mm. When (if) I get around to rebuilding the Tiger for a 4 stroke I will be adjusting things as necessary but if you did decide to install a Laser 100 in the current design it would require a certain amount of rework. Not necessarily a problem, just something to be aware of. Percy, did you have any issues fitting the Laser in? Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted July 9, 2016 Author Share Posted July 9, 2016 More or less, I enlarged the outline and then redrew all the structure to my own liking, with the intention of fitting an electric motor, so F1 moved forward a good bit compared to the original drawing. Someone who is happy to alter the structure would have no problem making up a replacement F1, slightly larger than mine, and positioning it further back to allow the Laser to fit. It would probably be helpful if I drew up a suggested ic conversion - it would only require a couple of formers to be redrawn and the fuselage sides shortening slightly. Of course, the moulded cowl wouldn't then fit but it's not difficult to make up a cowl from block balsa. I've been mulling it over while I was at work today and I think I might build an ic version for myself before too long. After ten years of flying entirely electric models I think it's probably time I played with a four stroke again! Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted July 9, 2016 Author Share Posted July 9, 2016 I must admit, with the benefit of hindsight, it would have made the ic conversion easier if, from the outset, I had drawn F1 sufficiently far back to allow a four stroke to fit in, and then used standoffs to bring the electric motor back into its current position. I'll probably adopt this method for future designs but for now it won't be difficult to come up with a conversion kit for the Tiger. The great advantage of things as they are is that I have been able to get the lipo to sit all the way forward, even protruding through F1 and into the cowl itself so that the cg is only about 10mm behind where I want it to be without having to add ballast. I'm working on a couple of biplane designs at the moment - one sport, one scale - so I'll make sure from the off that there is room to fit either ic or electric power with minimal alterations required. Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted July 25, 2016 Author Share Posted July 25, 2016 I finally have a windscreen I'm happy with. I made a template from three pieces of card then transferred the shape to a piece of .5mm clear plastic, which I then folded to make the final shape. I'm pretty happy with it although I will be adding a small fillet along the lower edge to simulate the metal frame. Quote Link to comment Share on other sites More sharing options...
Masher Posted July 26, 2016 Share Posted July 26, 2016 I'm glad I wasn't the only one to struggle with this 'little' detail! I ended up with many bits of card and wasn't happy with anything. In the end I went with 'less is more' and my template was a small crescent shape: Can't wait for the plans/CNC kit - hopefully in time for the winter building season? Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted July 26, 2016 Author Share Posted July 26, 2016 I must admit Masher, it's a job I hate! I find it tricky to get right but if it's done badly it looks awful and really impacts on the whole look of the model. I'll make sure the plan includes an outline of the template I made from card, although your crescent looks good too. I ended up looking at a website aimed at builders of full size Flybaby kit planes and the section on windscreens was very useful. The site gives advice on making windscreens in one piece (like yours) or three pieces (like mine, although on the model I used one piece and folded it). Interestingly, they recommend the three piece approach because of the ease with which any single pane can be replaced if need be - though of course that isn't really an issue on a model. The plans and parts will certainly be available in time for the winter building season - as soon as the model has flown I will be placing an order for the first batch of laser cut parts (always assuming, of course, that the first flight is a success, although I'm not anticipating any problems). The first flight should be any day now and the lead time for the parts is usually 2-3 weeks so all being well we should be up and running by mid-late August. Quote Link to comment Share on other sites More sharing options...
Masher Posted July 26, 2016 Share Posted July 26, 2016 That all sounds good Jim - good luck with testing! I have to say I really like flying this plane, having knocked up many flights in all conditions it always performs well and pretty much lands itself. I assume the larger version might even be better handling, it will be interesting to see. Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted August 6, 2016 Author Share Posted August 6, 2016 It's been a very exciting day here - the Tiger has flown! Being badly out of practice at flying models (and being mediocre on a good day) I entrusted the test flight to someone far more capable than I - no less a person than David Ashby in fact, while Graham Ashby kindly took lots of pictures for me. The model flew brilliantly, thrust lines and CG seemed to be spot on and it just needed a few clicks of trim on the elevator and aileron. David reported that the roll rate was a bit lazy and so I will be increasing the throws slightly. I was running it on a 4s lipo and it is a bit underpowered on this setup so I reckon 5s ought to be considered the minimum. Nevertheless, it flew very well indeed and that means I will be ordering the first batch of kits on Monday morning! As soon as I have the flying pictures I will post them on here. You will also notice that I have changed my profile name to reflect the fact that I am now trading as Nuviation Ltd. Our website can be found here: **LINK** Quote Link to comment Share on other sites More sharing options...
Masher Posted August 6, 2016 Share Posted August 6, 2016 Good news and a good website. Good luck with the venture, I hope to be one of the first customers. My 60" Tigre is looking forward to a rest! Quote Link to comment Share on other sites More sharing options...
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kc Posted August 7, 2016 Share Posted August 7, 2016 At the risk of being rude about a really good model might I suggest that it's not so much the windscreen is wrong but the pilot is too small for the model and the windscreen therefore seems too far forward. Or is it just me! I think if you compare to Percy's Ruhig Tigre photo with pilot in bobble hat which looks just about scale the difference is clear. I say this in the best spirit of wanting the model to look really realistic so you sell lots of kits. Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted August 7, 2016 Author Share Posted August 7, 2016 Thanks for the input kc, to be fair you're not the first person to suggest that a bigger pilot would look better. At the end of the day, it's a matter of personal choice, and anyway it could be a 1/4 scale model of a short pilot! I'm not about to change it now but I'm sure future builders will have their own ideas. Here is a picture of the model in flight, taken by Graham Ashby yesterday. 1 Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted August 7, 2016 Author Share Posted August 7, 2016 Details are being sorted out Percy, and I don't want to give away too much in case plans change but it looks like the model will be putting in an appearance in the magazine at some point. Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted October 20, 2016 Author Share Posted October 20, 2016 It's a couple of months since the first flight now and after a few more sessions with the Tiger I have been doing some tinkering. The roll response was a bit on the sluggish side but increasing the aileron throw has sorted this out and now it is much more in keeping with the model, but the biggest change I have made is to upgrade the power system to six cells, a more powerful motor and a bigger propellor. Static thrust is now up to ten pounds, although the upgraded power system has brought the all up weight to ten pounds as well so a thrust:weight ratio of 1:1, which is significantly better than I was achieving with four cells! With a 5000 mah battery, duration is ten minutes of mixed throttle flying with enough in reserve for at least a couple of attempts at landing. It must be said, however, that it took some surgery and a bit of head scratching to shoehorn the battery pack into the existing compartment! I have modified the drawings to make a bigger hatch which should make life easier, but the 4500 mah battery (which is what George at 4-Max recommended when I asked him) would have been a better fit while still giving plenty of duration. The increased weight of the new powertrain eliminated the need for nose weight and actually required a 30g weight to be added to the tailwheel bracket to bring the cg to the right spot - another reason to go with the lighter battery. Unfortunately the new motor is slightly longer than the old one and this has caused a gap to open up between the spinner and the cowl - easy enough to work around for someone building the model with the bigger motor from the outset but I will leave mine as is for now and see if it annoys me enough in the longer term to do something about it! The first batch of kits has been ordered and should be with me any day now, in the meantime, here are some pictures showing the mods I have made. The 6s 5000mah lipo just fits into the battery tray after a bit of trimming of the ply motor mount. A strip of mild steel under the tailwheel mounting screws compensates for the increased weight of the new powertrain. The annoying gap in front of the cowl - easy enough to fix when I get around to it. Quote Link to comment Share on other sites More sharing options...
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Jim Newberry - Nuviation Ltd. Posted October 20, 2016 Author Share Posted October 20, 2016 Thanks Percy. To be honest, I wouldn't recommend the 4s set up at all. It needed pretty much full throttle the whole time! 5s should work better. I haven't tried it on 5 cells but I understand the static thrust should be around 9lbs - that figure is based on information from George at 4-Max, and since he predicted the 6s thrust figure absolutely spot on, I'm inclined to believe his estimates! Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 20, 2016 Share Posted October 20, 2016 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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