Nigel R Posted October 18, 2023 Share Posted October 18, 2023 George always appears to specify small batteries aimed at short flights. YMMV, quite literally. 5 hours ago, Jonathan M said: SC 40 two-stroke, forgotten what prop but published output 920W = 175W/lb (again more than enough) Never in a month of Mondays will you see 920W from a 40 2-stroke on a standard silencer with a 11x6 prop and 10% glow fuel. A 0.40 will show about 600W, or 0.75 shaft HP. It's been done to death before, but the published figures for two strokes are likely to be ridiculous nitro content fuel, tiny prop, and unrestricted exhaust, in order to get the biggest number possible (before the conrod gives up). Start propping sensibly with regular fuel and a decent silencer and a very different picture appears. 125W/lb isn't underpowered, either, and I say that as someone who generally attempts to fit a fairly spicy motor to my airframes. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted October 19, 2023 Author Share Posted October 19, 2023 Nigel, you're right to question my use of published figures for IC motors etc. I'd dug out for my comment above the various calculation notes I'd made when I had my Wot4 and my Gangster, but ultimately my views are based on actual flying experience of both models. The bottom line for anyone building a Gangster 63 Lite as a proper classic aerobatic model for a range of flying conditions rather than something to pootle around with on a nice day, is that it'll be a pointless exercise to fit an under-powered motor / powertrain. If someone wants a super-light Gangster, e.g. MR's 4lb model quoted on his website (which George has presumably based his calcs on) and is happy to fly each Lipo for just a few mins before swapping it out, then equip it accordingly. I liked mine at 5.5lbs - lighter than the original, but still with the energy (both weight and thrust) to perform as a classic aerobat. If I'd wanted a light wing-loading floater or an overpowered modern hooligan then I'd have chosen another design. 2 Quote Link to comment Share on other sites More sharing options...
Nigel Heather Posted October 19, 2023 Share Posted October 19, 2023 13 minutes ago, Jonathan M said: I liked mine at 5.5lbs - lighter than the original, but still with the energy (both weight and thrust) to perform as a classic aerobat. If I'd wanted a light wing-loading floater or an overpowered modern hooligan then I'd have chosen another design. Thanks for the info. I'm content now with my gear. I've chosen a motor which is the next step up from the spec on 4-Max, going for an 80A ESC so I have headroom, 4S 3300 batteries that I already have, the trike undercarriage and might cap the wing ribs. The weight will be what it turns out to be. Confident that the power train will be good enough for me to get into aerobatic flying, probably not enough thrust:weight for a proper competition routine but I'm a long way from that and if I decide to go that way that will be the subject of a follow-on model. 2 Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted October 21, 2023 Author Share Posted October 21, 2023 Just to say that I'm feeling rather chuffed, as the club-mate I sold my own Gangster Lite to a year ago has agreed to sell it back to me... 😀 Quote Link to comment Share on other sites More sharing options...
Andy Stephenson Posted October 21, 2023 Share Posted October 21, 2023 Jonathan, Glad to see you rejoining the world of the power fliers again. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted October 21, 2023 Author Share Posted October 21, 2023 Cheers Andy Truth be told I was in a bit of a flap last Autumn having suddenly sold my house and thinking I was going to wind up in a rented flat with no scope to store let alone run-up IC models! As it happens I've now got a place with a garage - damp and cold in winter but at least its a garage! - and I was feeling real bad about having let the Gangster go... Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted October 21, 2023 Share Posted October 21, 2023 Good call Jonathan. Look forward to hearing how you get on with your Gangster and your aerobatics. Good luck. Quote Link to comment Share on other sites More sharing options...
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