Jonathan M Posted April 24, 2017 Share Posted April 24, 2017 So the Gangster 63 Lite kit has arrived. Laser-cut parts look pretty good and included is a full set of accessories. No plans but a reasonably clear instruction leaflet. I'll start construction shortly and post photographs as I go along. Not decided on colours of covering yet, but likely to use Profilm/Oracover. Now considering the power-plant and servos. On the basis that Mick Reeves suggests 0.20 to 0.40 two-strokes, and given how light the model is likely to be, I wish to power it appropriately for its core (classic pattern) tasks rather than excessively (constant get-out-of-jail-free power). So my engine of choice is the OS 35AX, within the suggested range but a modern and pretty powerful engine. It is rated at a maximum of 0.9 PS or 660 Watts, and with a likely final flying weight of 4lbs or so, this will provide about 165 Watts per lb, which sounds like more than enough! Servos I'm still thinking about. The cheap and easy route would be to fit Futaba S3003 standards, or their slightly dearer slightly more powerful bearing versions, but I'm wondering about the Ripmax New Power XL-38HMB standard, which is quoted at having an astonishingly high torque: Weight: 42g Bearings: Twin Ballrace Dimensions: 39.9 x 19.8 x 47mm Gear Type: Metal Speed (4.8v): 0.16secs 60Deg Torque (4.8v): 9.0Kg/cm At £13 each, I'd use these for elevator and rudder (including steerable nose-wheel), but does anyone have experience of how reliable the New Power servos are? For throttle and ailerons, I'm wondering whether a slightly smaller mini servo would suffice, i.e. Hitec HS225M at £17 each: Weight: 30g Bearings: Top ball bearing Dimensions: 32.3 x 16.8 x 31.0mm Gear Type: Metal Speed (4.8v): 0.14secs 60Deg Torque (4.8v): 3.9Kg/cm I've bookmarked the few (partial) build-threads here for insight (and errors to avoid!) and hope to produce as complete a build-blog as possible... and get started as soon as possible! Jon Edited By Jonathan M on 24/04/2017 16:20:22 Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted April 24, 2017 Share Posted April 24, 2017 Can't wait to see this Jon, but don't skimp on the aileron servo, as I normally fit 2, even where one is provided, one in each wing, but is a well worthwhile faf, but there is no reason not to fit 1 servo central in the wing I do put an half size hitec81 on the throttle though. All your specs are well within the design needs Am looking to build too Quote Link to comment Share on other sites More sharing options...
Masher Posted April 24, 2017 Share Posted April 24, 2017 Hi Jon I have one of these and it flies very well. I am using standard Futaba servos and the 'classic' Irvine 53 2 stroke. This combination feels perfect - certainly not over-powered. So.............the 35AX may be a bit small? I am not a speed freak! Quote Link to comment Share on other sites More sharing options...
Nigel R Posted April 24, 2017 Share Posted April 24, 2017 I'm fitting HS225s in the wing of a similar sized (albeit heavier) build, a HS81 on throttle and most likely some old JR507 standards on elevator & rudder. Or to put it another way - snap! The new power specs look good, possibly "too good" for the money? I take the cheaper servo specs* with a pinch of salt - but I believe for your use any standard size servo would be ok. I am a bit lairy of fitting mini or micro sized servos to the rudder and elevator though. Not worth the 1oz weight you save - IMO. Ailerons with two servos, well you have two ailerons, so some chance of control if one servo goes wrong, and a single aileron is a light load. * cheap electronics specs full stop, really. There are a lot of optimistic specs around for cheap devices! Quote Link to comment Share on other sites More sharing options...
dave parnham Posted April 24, 2017 Share Posted April 24, 2017 I use the 3003 Futaba servo's in mine and a 148? for throttle.....mine has an Irvine 46 in it and its adequate but I think the 53 would liven it up and make it better, I've been meaning to change over for some time, just not gotten around to it yet. Quote Link to comment Share on other sites More sharing options...
Phil Francis Posted April 24, 2017 Share Posted April 24, 2017 Don't use New power Servo's unless you want a world of hurt. Tried a couple a while ago they don't centre well, 1/4" either side of centre. Phil Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 24, 2017 Share Posted April 24, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted April 24, 2017 Author Share Posted April 24, 2017 Re engine: The OS 55AX outputs 1.8PS max, and the Irvine 53 1.7PS (and is described as perfect for 3D, which this isn't!). Both are effectively twice as powerful as the 35AX. If the consensus is that 35AX is definitely too weedy (anyone for the defence?) then I might consider something like the 46AX which is rated at 1.6PS. Re servos: Yes, good advice thanks, so I've rejected the Ripmax New Power jobbies. Will probably just go for Futaba S3001 standards on Rudder and Elevator (unless a metal-geared but affordable alternative is suggested, especially as the rudder one will need to drive the steerable nosewheel on sometimes rough ground), with a Hitec HS81 for throttle and two HS85MG 'mighty mini's for each aileron. Re build: Nothing yet, just a good examination of the parts and the instructions, which are beginning to make sense. I'll replace the plastic spinner with a nice alu one, and think about how to beef up the flimsy cowling with cloth and epoxy. Jon Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted April 24, 2017 Author Share Posted April 24, 2017 PS: Mick Reeves' instructions recommend using CA for the vast majority of gluing. I like this method for speed, but are there good arguments for Aliphatic (my favourite for scale rubber) or PVA (the slowest drying)? Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 24, 2017 Share Posted April 24, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted April 24, 2017 Share Posted April 24, 2017 Hi My thoughts are based on the "old" Gangster I had, foam wing job and it would go ballistic on an Irvine 61 with the bog standard exhaust, the new version with the built up structure would surely go well with something less. My guess is an OS 55 would have more power than my old Irvine - depends what you want at the end of the day. If you want to pattern fly then power is important, if you are to use it as a sport plane, I'd probably find something less aggressive. As far as what glue to use, CA will give a fast accurate build. I built a Flair Hooligan and had it covered in 24 hours using CA. However my choice of glue now is generally Aliphatics in the warmer weather, takes ages to set in the winter as I found the last few months, but with summer coming the Aliphatic is fine. If you are going the CA route, you don't need to use the super thin CA for everything and you gain some control. The super fast thin stuff is all a bit sudden if something is not quite right. Just my thoughts. S Quote Link to comment Share on other sites More sharing options...
Masher Posted April 24, 2017 Share Posted April 24, 2017 Unfortunately it looks as though they are still supplying the same old rubbish cowl - best consider building one up in situ from balsa Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 24, 2017 Share Posted April 24, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Nigel R Posted April 25, 2017 Share Posted April 25, 2017 Posted by Jonathan M on 24/04/2017 20:52:51: Re engine: The OS 55AX outputs 1.8PS max, and the Irvine 53 1.7PS (and is described as perfect for 3D, which this isn't!). Both are effectively twice as powerful as the 35AX. If the consensus is that 35AX is definitely too weedy (anyone for the defence?) then I might consider something like the 46AX which is rated at 1.6PS. I wouldn't pay too much heed to manufacturer ratings on 2 strokes. Those (open exhaust, tiny prop, high nitro %) power outputs will not match what you get with a sensible prop, fuel and silencer. More conservatively, I'd suggest around 1.25hp per 10cc from any given two stroke on standard silencer, propped down to 10 or 11k. Most 2 strokes work out quite close to this number. Add a pipe and it rises to around 1.6hp per 10cc, with commensurate extra weight. Another way of looking at it for aerobats - 1lb per 0.1 cu in gets you "good" vertical performance. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted April 25, 2017 Author Share Posted April 25, 2017 Posted by Masher on 24/04/2017 21:38:23: Unfortunately it looks as though they are still supplying the same old rubbish cowl - best consider building one up in situ from balsa Option A is to use the flimsy plastic as an armature over which I'd build up epoxied glass. Option B is to build up a cowl as you and Percy suggest. Would this be best done as an extension to the fuselage sides, i.e. as cheeks with bottom and top added, or as a separate balsa 'cowl' to be glued to the firewall, or screwed and therefore removable? Edited By Jonathan M on 25/04/2017 10:19:42 Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted April 25, 2017 Author Share Posted April 25, 2017 Posted by Nigel R on 25/04/2017 09:45:08: Another way of looking at it for aerobats - 1lb per 0.1 cu in gets you "good" vertical performance. Cheers Nigel for that rule of thumb. The 46AX it is then! Quote Link to comment Share on other sites More sharing options...
TIM Shaw Posted April 25, 2017 Share Posted April 25, 2017 Posted by Nigel R on 25/04/2017 09:45:08: Another way of looking at it for aerobats - 1lb per 0.1 cu in gets you "good" vertical performance. Excellent Rule of thumb! I find the modern 36s quite capable of powering 53", 4ib pattern type models, while once you get up to 6lbs you need a 61, and a pipe much beyond that.. Drag, due the model size is also significant I guess, so even on a very light Gangster 63 I wouldn't consider anything less than a good 46. I had on original with an ASP 61 in it that was great, also had a 52 with an OS 40 FP which flew nicely - interestingly though I felt it was less nice with Schneurle ported 45 - maybe the additional weight didn't help. And then there was the 42, interesting to fly while the OS21 FSR kept running, had a glide like a brick when it stopped.... Quote Link to comment Share on other sites More sharing options...
gangster Posted April 25, 2017 Share Posted April 25, 2017 I reckon that OS35 would be perfect. It is way lighter than the old 63 and motors are more powerful Than they were. I have used an electric motor about 650watts. As far as servos I have used standard size can't remember which ones I can see no point in using little ones. There is plenty of space and the weight is negligible Defo use 2 for the aelerons. The world has moved from the days when a servo cost a weeks pay and it was worth enduring the slop and the fight between the aeleron horns and anything else in the fuselage. We don't need to go back to that. Also much easier to manage the set up differential expo etc. Totally agree with the fixed nose wheel comment I suggested that before and got strange comments but I fly in the air and find that turning control by wheel movement has no effect above an altitude of 5mm. The rudder however works on the ground Also certainly with an electric set up it can be airborne in feet if you want certainly faster than the reaction for steering time of any modeller I have ever met Quote Link to comment Share on other sites More sharing options...
onetenor Posted April 25, 2017 Share Posted April 25, 2017 Another thing about steerable nose wheels is you usually and up with a scrap servo too Quote Link to comment Share on other sites More sharing options...
Masher Posted April 25, 2017 Share Posted April 25, 2017 For the balsa cowl option I would build it on to the fuse once completed. Look at any/most of Peter Miller's models to get a good guide as to how it's done. It is also possible, if a little tricky, to cover the balsa cowl with heatshrink film which, IMO, is more successful than trying to find glow proof paint! Quote Link to comment Share on other sites More sharing options...
Nigel R Posted April 25, 2017 Share Posted April 25, 2017 "Drag, due the model size is also significant I guess" Another excellent point - Low weight gets you good slow speed performance. Power gets you high speed performance. 1 Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted May 2, 2017 Author Share Posted May 2, 2017 After much mulling, I've just ordered the OS 35AX Good points made above, especially the one about drag. However (and I know its not a direct comparison but) if my 6lb Acrowot can go almost unlimited vertical with the ASP 70FS (800 watts), then the 4lb Gangster should find more than enough grunt from the 35AX (660 watts)! I'll need to order a glass-filled mount suitable for the 35, as the one supplied in the kit is for - ahem! - a 45 to 60 sized engine! What, by the way, are the merits of a side-mounted engine over an upright one? Jon Edited By Jonathan M on 02/05/2017 13:01:23 Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted May 2, 2017 Share Posted May 2, 2017 I hope you get the 35 AX, I thought they were out of production. At least that is what I'd been told. If you are unlucky then SC engines or try "Just Engines". Sidewinder motors do give you a better chance to direct the exhaust down and away from the fuselage. Uprights tend to decorate the fuselage with nice sticky exhaust spray. Other than that, the aesthetics come into play. Cleaner profile also with the head sticking out of the side. Quote Link to comment Share on other sites More sharing options...
Jimbo565 Posted May 2, 2017 Share Posted May 2, 2017 Here's mine with 55ax and built up cowl. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted May 2, 2017 Author Share Posted May 2, 2017 Stuart, both Servo Shop and Just Engines are currently out of stock of the 35AX (but JE told me new stock was due in shortly), so I purchased it from Slough Radio Control Models. Sidewinder sounds the most sensible orientation then in terms of goo-avoidance! Jim, cheers for that photo. How does your built-up cowl attach to the fuselage? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.