Colin Leighfield Posted July 27, 2017 Share Posted July 27, 2017 Music to my ears Martyn. The hollowed out Liteply is for me, count me in. I will be away for two weeks from this weekend, back on 13 August. Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted July 28, 2017 Share Posted July 28, 2017 Not that much of a 'balsa vs. ply' debate around here it seems, Martyn. Holidays, I guess. A bit off topic I'm afraid, but my intention is to build a Svenson Vicomte next winter, trying to get some experience and hopefully finish it before the Fury build starts. The 'revisited' kit was recreated (CAD) and laser cut by Belgian JVM Models. His design proposes some 3mm balsa ribs like the original has or optionally some hollowed 2,5mm airplane grade ply. The least you can say is that he made good use of the available wood surface. The 24 needed ply ribs are 3,65g lighter than the balsa equivalents but are quite flimsy and needed some capstrips. As you wrote, Martyn, there isn't really a weight penalty except if your 3mm ply weights a lot more. (pictures courtesy of JVM Models) Once sanded, the completed wing looks very nice and it's nearly a shame to cover it up. Anyhow, whatever the group's decision might be, please count me in. ... and in the meantime, both of you should fully enjoy your holidays. Cheers Chris Edited By McG 6969 on 28/07/2017 09:01:15 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted July 28, 2017 Share Posted July 28, 2017 I for one am not going to get sucked into the lite ply/balsa discussion A quick question for somebody that has the plan already from traplet? can you measure the top wing span please? I am assuming it is 60" as that is what is mentioned on the description? I appreciate only half the top wing is shown on the plan. Cheers Danny Quote Link to comment Share on other sites More sharing options...
John Timmis Posted July 28, 2017 Share Posted July 28, 2017 Exactly 60" Cheers John Quote Link to comment Share on other sites More sharing options...
kc Posted July 28, 2017 Share Posted July 28, 2017 Liteply v Balsa Preumably you could settle all discussion scientifically by weighing a sheet of Liteply, then a sheet of balsa of suitable grade. A very quick calsulation would get weight per sq ft or M. Then I would expect your CAD would have a way to calculate the area removed on the Liteply design compared to the solid balsa. The result of area removed compared to weight difference would settle the matter! My guess is they will be the same .......or within the variability of balsa that might be used. But the advantage of Liteply will be greater consistency of material and the sheets will prove more economical. Probably the laser cutter people would prefer ( = quote cheaper) Liteply for the same reason. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted July 28, 2017 Share Posted July 28, 2017 Thanks John kc exactly why I didn't want to get drawn into a conversation on lite ply. I do not like lite ply, in my opinion it is heavy and weak. As you say the laser cutters love it as it is cheap and consistant, and comes in larger sheets than balsa. Maybe I am just old fashioned Cheers Danny Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted July 28, 2017 Share Posted July 28, 2017 That's an interesting view on liteply kc. I've never used the stuff, so before I start the Fury I'll buy some and give it a go. However, it appears that its made from ceiba wood that is a similar weight to obeche, which is heavier than balsa. The balsa we use in models has a density between about 4 and 30 lb/cu ft. The light stuff is at a premium and is normally snapped up before it gets to the shops. So by the time the average modeller gets to his/her local store, only the heavy stuff is left. This may be heavier than liteply! Intuitively, as liteply is made from sheets of wood generally heavier than the lightest balsa and taking into account the glue, it must be the heavier option. I'll report back when I've done some testing. Quote Link to comment Share on other sites More sharing options...
kc Posted July 28, 2017 Share Posted July 28, 2017 Well there is liteply and there is liteply - it varies. SLEC list Liteply and they also list " laser ply Poplar ply". Some I have used is extremely light colour almost white, while the sheet I have now has a distinct grain in brown and a rather stringy texture which doesnt cut as cleanly. It was cheap stuff bought at a show. This sheet of 3mm weighs 110 gram/sq ft I would expect the nice white liteply to weigh less but I haven't any on hand to weigh. Whilst the first sheet of 3mm balsa I found was 33 gram/sq ft and another 60 gram /sq ft This 60gram sheet is what the lasercutter might use because a set of very nice balsa lasercut ribs from DB actually weighs 55 grams with their outers and just happen to be 1sq ft.. Just for comparison a sheet of 1.5mm birch ply weighs almost the same at 122 gram/sq ft ( sorry for if the mixed measurements offend - its just handy as 4inch by 3ft is a sq ft, ply sheetsare in feet and scales weigh in gram.) So solid balsa ribs are likely to be half the weight of solid liteply ribs. So half of the liteply rib would need to be cut away to equal the balsa. Possible with big fat ribs maybe but possibly not on thin wing sections. As ever it all depends on wood selection - if you select nice balsa yourself it would be lighter, if you leave it to the lasercutter then fretted out liteply might be safer. But balsa is so much nicer to work with........ Quote Link to comment Share on other sites More sharing options...
Nev Posted July 28, 2017 Share Posted July 28, 2017 Hi. I imagine there are a lot of ribs, so a cut set would be a bonus in any medium. I have never built anything using light ply ribs, so haven't really got a lot to go on. My only experience would be an ARFT, which was well built, very light and flew great, until I eventually did something silly too close to the ground. At that point it completely crunched up and with so little wood no chance to repair. I assume these wings are not sheeted in any way, if that's the case my preference would be balsa or maybe flying lessons. Nev. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 28, 2017 Share Posted July 28, 2017 As KC says, there's Liteply and there's Liteply. I'm going to stay open-minded on this one, I had problems with the Chipmunk because of the poor quality of the balsa that had been used for making the ribs, but it's my own fault because I should have sent them back! Quote Link to comment Share on other sites More sharing options...
Gordon Whitehead 1 Posted July 28, 2017 Share Posted July 28, 2017 Back in 2006/2007 I built the Westwings EDF Hunter and Hawk kits, and discussed with Pete Shepherd, the models' designer, the choice of birch ply for formers and wing ribs instead of liteply or balsa. Pete explained that the reason for this choice is that birch ply can be fretted out using CNC machinery to more slender profiles than either liteply or balsa and the components demonstrate significantly higher strength than liteply and balsa with a minimal weight penalty. I remember being impressed by the strength of the components, and the Hunter in particular came out very light. The birch ply used was in fact aircraft grade plywood which had not been signed off for aviation use, so I imagine that it would be far more expensive than liteply. I have used liteply and have a few sheets in stock. I don't like the stuff as it always warps, and I rarely seem to be able to buy the same material twice in succession. I wonder how many types of liteply there are. That being said, the two or three ARTFs I've owned in the past five or six years have held together successfully with their liteply fuselage structures, though the Sebart Katana 50e did have some design flaws; ie holes where there should have been wood, leading to the u/c departing twice on soft landings before the addition of birch ply webs over the holes (only 1mm thick) to prolong the model's life. Maybe it's worth noting that the wing ribs on these models, a GP Ultimate 160, Nano Boomerang jet, and the Katana, are all made from balsa. In fact, had the Kat's ribs been fretted-out liteply, I think the ribs would have shattered where the wheel spats went through the wing lower surface. Gordon Quote Link to comment Share on other sites More sharing options...
Ken Lighten Posted July 30, 2017 Share Posted July 30, 2017 **LINK** Is this the same plan/cut parts? If so, it SEEMS to be still available here, haven't looked into it in any detail myself Ken Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted July 30, 2017 Share Posted July 30, 2017 We have a while to go yet Ken and several options on parts CheersDanny Quote Link to comment Share on other sites More sharing options...
Stumps Posted July 31, 2017 Share Posted July 31, 2017 Morning Ken, I don't think that's the Bryant Fury, but one by another designer that is part of the Flying Scale Models mag. From memory, I think it's a little smaller as well. regards Stumps Quote Link to comment Share on other sites More sharing options...
Martyn K Posted July 31, 2017 Share Posted July 31, 2017 Another download for you, many thanks to Andy Sephton for the content.. Fury Miscellany 1 Regards Martyn Quote Link to comment Share on other sites More sharing options...
Martyn K Posted July 31, 2017 Share Posted July 31, 2017 My thoughts regarding Liteply My first experience with the stuff was when I built my Puppetteer about 12 years ago. The stuff was quite thin and quite light but was bowed before i even started building the model. However, following the instructions from Flair, it actually went together really well with really straight ribs. More recent models have used a harder grade of ply that is stiffer/stronger (and heavier ) but that means I can hollow then out even further Most of my models recently have had laser cut liteply wing ribs, When I built the two Kwik Flis last Christmas - the tapered wing version had laser cut (with hollowed out cores) ribs, the the straight wing had hand cut balsa ribs. There was no significant difference in weight between the two wings. As far as I can see the benefits of using liteply are: 1. Its more consistent than balsa. Cut the wrong weight balsa and it will be too heavy or too weak. Its difficult to get enough decent balsa of the right density for a lot of wing ribs required for a model of this size. 2. Its easier to work with for laser cut parts. edges stay sharp and well formed, its more rugged - particularly for edge pieces 3. Its significantly cheaper. Material costs are lower but also its wider/longer, Parts placement is much more simple with less waste The downside of liteply 1. Its difficult to repair following a bad crash. Hollowed out ribs leave very little material for gluing back together and a repair is more complex. However, balsa can be a nightmare to fix as well, in both cases we should not be thinking of repairability but flyability and consistency of construction. 2. It is slightly heavier. But the weight can be managed by careful design At the end of the day, I can produce two cad sets - one for balsa and one for liteply and you can choose which set you want. I'll probably go down the liteply path or perhaps a hybrid Martyn Edited By Martyn K on 31/07/2017 09:59:06 Quote Link to comment Share on other sites More sharing options...
2W Posted August 1, 2017 Share Posted August 1, 2017 Hi Danny, I was about to sign up for the build, but the Traplet problem put me off ! I am game for this challenge, having nearly completed scratch building the Peter Rake designed Albatros D.XI which had a number of issues as far as I am concerned: Accurate wire bending, Wing settings and the construction of an accurate jig, and Wheel construction, for which I used air hose. I hope the plans can be made available at least – I don’t mind cutting the parts, but without a plan….. William Quote Link to comment Share on other sites More sharing options...
Martyn K Posted August 1, 2017 Share Posted August 1, 2017 Posted by 2W on 01/08/2017 14:16:36: Hi Danny, I was about to sign up for the build, but the Traplet problem put me off ! I am game for this challenge, having nearly completed scratch building the Peter Rake designed Albatros D.XI which had a number of issues as far as I am concerned: Accurate wire bending, Wing settings and the construction of an accurate jig, and Wheel construction, for which I used air hose. I hope the plans can be made available at least – I don’t mind cutting the parts, but without a plan….. William Hi William We should be able to sort out a plan for you or anybody here Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted August 2, 2017 Share Posted August 2, 2017 William it would be great if you can join in, the Peter Rake designs are gorgeous but not for the feint hearted. The Fury will be a challenge for me too as I am not experienced with scale biplanes, but I already have lots of the problems ironed out in my head. Having got more and more into the detail on the Fury, (thanks to all the fabulous documentation Martyn and Andy have found) I am worried. If you thought the Chipmunk had detail, blimey the Fury makes the Chippy seem very simple. So we may have to lower our sights a little, not sure I know how to do that so may need help there But shock absorbing undercarriage is a given Cheers Danny Quote Link to comment Share on other sites More sharing options...
Stumps Posted August 2, 2017 Share Posted August 2, 2017 Danny, Do you think a laser 100 would be OK or a little OTT for the Fury? I've got one currently awaiting a new airframe. regards Stumps Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted August 2, 2017 Share Posted August 2, 2017 Hi I dont think it would be overkill at all. I was surprised how big the airframe is when you unroll the plan. The fus is 56.5" long and the span 60" It probably went on a Merco 91 or something similar back in the mid seventies. The problem will be getting it in the cowl. Dennis let the head protrude which will certainly aid cooling as that will be a major headache for you IC'ers. I believe Martyn is thinking of the RCV 90?, which will fit well if he can arrange cooling. Cheers Danny Quote Link to comment Share on other sites More sharing options...
kc Posted August 2, 2017 Share Posted August 2, 2017 Did you actually mean Merco 91? I thought the 61 was the largest Merco I had heard of and that 61 was also the limit in competition so nobody used anything larger in that era. Maybe I am wrong? Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted August 2, 2017 Share Posted August 2, 2017 Sorry KC you are quite right Quote Link to comment Share on other sites More sharing options...
Martian Posted August 2, 2017 Share Posted August 2, 2017 Danny the plan shows a dummy control cable for the rudder could we not just make it pull pull Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted August 2, 2017 Share Posted August 2, 2017 Hi Yes, I must confess I saw the dummy cable for the elevator, but thought it was pull-pull for rudder. You have obviously looked harder than I have. But yes a very good idea. It might be doable to use pull pull on elevator, I did that on a Hurricane and it worked very well. Cheers Danny Quote Link to comment Share on other sites More sharing options...
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