Peter Jenkins Posted January 20, 2019 Share Posted January 20, 2019 I flew a clubmate’s Gangster 75 and I was so impressed with it that I put out feelers to see if there were any kits still lying around. Luckily, via another friend, I was able to buy an untouched kit together with an unused Super Tigre 90 engine. I originally started the build in 2011 and took loads of photos as I intended to write up the build. However, I got deeply into F3A competition and the Gangster build ground to a halt. I had by that stage built the wing and started the fuselage. In Nov 2018, I re-started the build with the intention of completing it by the end of 2018. Well, I failed but my new deadline is end of Jan 2019. There was no plan provided but I’ve not really needed one. There is a 4 page instruction manual but, as this kit is intended for someone with some experience of building, there isn’t much help provided. To be fair, it really doesn’t need much as the process is quite straightforward. So, here’s what I started with: and here it is unpacked Quote Link to comment Share on other sites More sharing options...
SIMON CRAGG Posted January 20, 2019 Share Posted January 20, 2019 What a great project. I had one powered by an MVVS engine, which was a fantastic model.......until simebody up the field switched on when omn the same freq. (35mhz). Went in full chat from 200ft. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 20, 2019 Share Posted January 20, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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Former Member Posted January 20, 2019 Share Posted January 20, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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Ron Gray Posted January 20, 2019 Share Posted January 20, 2019 I think you may have stuttered Percy. Quote Link to comment Share on other sites More sharing options...
SIMON CRAGG Posted January 20, 2019 Share Posted January 20, 2019 Posted by Percy Verance on 20/01/2019 07:42:28: What the hell happened there????? You posted three times! Yes, I had the peg and another pilot switched on, walked out to the patch and started doing his pre-flight checks. All went pear shaped from the on. He paid out via his house insurance somehow, and I bought a Mick Reeves "G Man", which turned out to be just as good. Quote Link to comment Share on other sites More sharing options...
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sgwlm Posted January 20, 2019 Share Posted January 20, 2019 brings back memories, i had the 42, 53 & 63 back many many years ago, never had the 75, instead at that time i had the Galaxy Mystic, probably the close competitor for the gangster. i always wanted the gangster twin but could not manage it back then, maybe i should look for one now. Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 20, 2019 Author Share Posted January 20, 2019 I started with the wings. It’s a long time since I built a model from a kit (around 1969 I think) and one with foam wings was also a novelty. I started by gluing on the leading edge and trailing edges. To keep costs down Mick Reeves seems to use only 36 in balsa strip so you get little add on pieces for anything over 36 in. I used PVA to glue both strips in place supporting the glue by taping the LE and TE to the wing with masking tape. The next step was to sand the LE and TE to blend in with the wing making sure that the veneer on the wing wasn’t damaged in the process. Quote Link to comment Share on other sites More sharing options...
gangster Posted January 20, 2019 Share Posted January 20, 2019 Ah yes Percy. The aileron flutter. That is one thing I never understood. I have had a few 52s and 63s and on each one I did not build the strip ailerons right to the tip. I never had the aileron flutter that so many others had I do not know why that was not shown in the instructions. As for economy of design MR was very clever they used so little wood Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 20, 2019 Author Share Posted January 20, 2019 The next job is to glue on the wing tips. These are just thick sheet and so all pretty easy. Once the glue had dried, I used a razor plane to shape the tips finishing with my trusty sanding block. The next job was to mark out the ailerons using the dimensions shown in the instruction leaflet. I have to say that I wasn’t looking forward to cutting out the ailerons using a hacksaw blade. I did have difficulty in keeping the blade at the correct angle at all times! Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 20, 2019 Share Posted January 20, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 20, 2019 Author Share Posted January 20, 2019 Indeed - no strip ailerons on this baby! For the avoidance of doubt, the 75 refers to the wingspan in inches. Interestingly, this is about the same span as my 2 mtr class Majestic (1905 mm in new money) and so larger than the current fashion in F3A designs. The Gangster fuselage is a lot shorter than 2 mtr so in this case the span is greater than the fuselage. That being said, the one I flew was a beautifully behaved aerobatic aircraft. Fingers crossed that I end up with the same! The next fiddly job is facing the ailerons with the supplied sheet. This was a bit of a struggle as I had not been able to make an accurate cut. This required the use of filler to sort out the effects of my butchery. I decided to hinge the ailerons with Robart pin hinges and left this till later in the build. The ailerons are top hinged with a closing V on the underneath so you get some built in aileron differential. I decided to fit two aileron servos so had to cut out a servo box in each wing and then line each with balsa. Mick suggests running the servo lead to the servo by cutting a V into the under-surface of the wing to run the aileron leads in. I didn’t like this idea so as I had a piece of aluminium hollow rod in my workshop, I sharpened the tube end and used that to burrow through the wing. The problem is keeping the hole going in the right direction so that the tube exits in the servo cut out! Success! Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 20, 2019 Share Posted January 20, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 20, 2019 Author Share Posted January 20, 2019 Percy, I chose that aluminium tube as it would produce a hole large enough for the servo plug, and more importantly, the servo extension lead connection to fit. Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 20, 2019 Author Share Posted January 20, 2019 Next up was to fit the undercarriage bearer. The Gangster 75 is a tail dragger so the wings get the u/c blocks. This is fairly straight forward. I made sure I used a generous amount of epoxy and wiped away the excess that was squeezed out. Next job is to join the wing panels. Once done, you now have a 75 inch plank which makes you think twice before picking it up and turning round! I used araldite to join the wings and checked that both wing panels were at the same incidence and that the dihedral was spot on. I left the glue to dry overnight and then used fibre glass gauze to reinforce the wing join. I did this using 3 layers of the fibre glass. The first layer was kept fairly narrow, the next layer was just larger than fuselage width and the third layer was wider still. Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 21, 2019 Author Share Posted January 21, 2019 At this point, I put the wing to one side and started on the fuselage. I had fortuitously bought a SLEC building jig at a Club night and this came in very handy as you will see. The fuselage side was made up of 4 parts with a but joint between the front and rear parts. There is a large doubler but I felt that the proximity of all the butt joints required a ply reinforcement on the outside – see later on. This was based on my friend with the Gangster 75 having had the fuselage snap at the butt joints on a heavy arrival. Having managed to make two handed fuselage sides (phew), it was time to bring the SLEC building jig into play to frame up the fuselage sides with the first 3 formers. There is no up/down thrust specified so it was simply a matter of checking for a vertical with a small try square but 1.5 deg right side thrust is required. A quick recourse to trigonometry gave me the required measurement by which the engine mounting bulkhead needed to be canted to the right – or rather, as the fuselage is built upside down, to the left! Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 21, 2019 Share Posted January 21, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 21, 2019 Share Posted January 21, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 21, 2019 Author Share Posted January 21, 2019 Percy, you are quite right. I forgot to take a photo of the all 3 fibreglass layers. The photo shows only the first one, The second one extended out to just beyond the edge of the fuselage and the third one extends further out by the same amount. So there is a progressive thinning of the reinforcement with the greatest at the middle, the next greatest to just outside the fuselage line and so on. That achieves the same effect as a diamond shape in a different way that is a gradual change in reinforcement rather than an abrupt end. The entire fibreglass reinforced area is 9 inches wide. I have another photo which will show the extent but that's some way off in the build. All 75s are tail draggers - at least that's what comes with the kit and instructions I have. I'll put a scan of the exploded view up to show how the beast goes together. Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 21, 2019 Author Share Posted January 21, 2019 Here's the exploded view of the Gangster 75 - sorry about the quality! Quote Link to comment Share on other sites More sharing options...
rcaddict Posted January 21, 2019 Share Posted January 21, 2019 hi peter i have a 20 year old gangster 75 with a ST 90 up in my loft which one of these days i am going to re-cover and do a leccy conversion, it is a joy to fly, oh and its defo a tail dragger Edited By rcaddict on 21/01/2019 18:45:57 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 21, 2019 Share Posted January 21, 2019 Ah, you're building a foamie Should be lovely when done. Interesting choice to do a straight butt joint for the fuselage. When laser cutting makes a good scarf (or some other keyed joint) an easy possibility. Mind you, your big doubler should cover all your bases there. Quote Link to comment Share on other sites More sharing options...
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