Cliff 1959 Posted July 24, 2021 Share Posted July 24, 2021 Hi Richard, thanks for that reply. I've made my blades and added a 0.4mm shim using the material supplied with the parts from Malcolm at Coolwind, all will become clear in video number four 'Blade Construction' when I get the final filming and editing done. In the meanwhile, as you suggested, here is a link to the first of three videos (the others being linked at the end of each part): 1 Quote Link to comment Share on other sites More sharing options...
Cliff 1959 Posted July 27, 2021 Share Posted July 27, 2021 Hi guys, is the Coolwind rota head set to 90° to the mast on the Atom as viewed from the side? Also I plan on 1° to the left (viewed from the rear), or should it be a little more? Quote Link to comment Share on other sites More sharing options...
Cliff 1959 Posted July 27, 2021 Share Posted July 27, 2021 Also should I remove this small section of blade to allow full movement? I'm thinking I should. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted July 27, 2021 Author Share Posted July 27, 2021 7 hours ago, Cliff 1959 said: Also should I remove this small section of blade to allow full movement? I'm thinking I should. Cliff, Yes it should pivot clear of any obstructions. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted July 27, 2021 Author Share Posted July 27, 2021 (edited) 8 hours ago, Cliff 1959 said: Hi guys, is the Coolwind rota head set to 90° to the mast on the Atom as viewed from the side? Also I plan on 1° to the left (viewed from the rear), or should it be a little more? Cliff, Yes, 90 degrees to the mast is a good starting point. 1 degree left trim is also a good starting point. You can alter this if need be once you start your trimming hops. Edited July 27, 2021 by Richard Harris 1 Quote Link to comment Share on other sites More sharing options...
Cliff 1959 Posted July 30, 2021 Share Posted July 30, 2021 The Atom is finished, now all I need is a couple more practice sessions on the Luobo and I'm ready to go, thanks guys for all the help and advice. Quote Link to comment Share on other sites More sharing options...
Max Z Posted January 11, 2022 Share Posted January 11, 2022 (edited) On 27/07/2021 at 21:08, Richard Harris said: 1 degree left trim is also a good starting point. Hi all, Back here to tell that my Atom has been repaired after its "dramatic landing" a few years ago ( is it 5 years already?), and is ready for its next flight. The head is set the same way as before, with a bit of trim to the left ( just a bit more than 1 degree I guess), but in a discussion on the Dutch forum the question popped up what the background of this is. The advancing/retreating blade theory seems to work out in the opposite way, i.e. advancing blade on the right = more lift on the right = rolling to the left, so why give it a bit of trim in that direction as well? What am I overlooking here? Edited January 11, 2022 by Max Z Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted January 11, 2022 Author Share Posted January 11, 2022 2 hours ago, Max Z said: Hi all, The advancing/retreating blade theory seems to work out in the opposite way, i.e. advancing blade on the right = more lift on the right = rolling to the left, so why give it a bit of trim in that direction as well? What am I overlooking here? Max, The cone angle of the rotor disc will add a roll element in the direction of the advancing blade side, in our case this is an anti clockwise rotation so left trim is needed to compensate. As this cone angle increases so does the applied rotor offset trim, too much cone can also pitch the nose up or down depending on rotor direction when turning using roll (not yaw). It is impossible to eliminate coning of the rotors the same as a fixed wing will always have dihedral (be it minimal) due to the forces acting on them. Heavier blades are the most obvious way to flatten the cone angle on a rotor disc (generally by adding tip weights forward of the CG), the issue here is that it adds a lot more inertia to the blades, creates a slower spin up and increases loads on the whole head control system. I experimented with heavier blades years ago and a simple tip over can result in extensive repairs. Due to this I generally prefer a model that has a medium weight blade as with the Atom, the down side is that left trim needed and varies from model to model dependent on its mass (or the cone angle). To give yourself a head start turn on your Atom hold it and get the blades up to full RPM into wind, if you then position it above your head holding it lightly you should be able to 'feel' any roll acting on it, simply trim to suit until it feels neutral then go for the hops. Hope this kind of explains things? Rich Quote Link to comment Share on other sites More sharing options...
Max Z Posted January 12, 2022 Share Posted January 12, 2022 (edited) Thanks Rich. Yes I know how to trim and fly the Atom (remember Greenacres 2015?), but I could not work out the left trim to avoid rolling over to the right on take-off, in its relation to the advancing blade having more lift on the righthand side. But I have since realised that there is more to it. My conclusion in short: thanks to the blade flapping hinges the difference in lift is compensated for by automatically tilting the rotor cone to the left to balance things, but as your axis of rotation would be vertical without trim, you are effectively steering to the right, resulting in said roll to the right. By trimming the rotation axis to the left this can be avoided. Now these are all my own considerations, with some snippets of previously acquired ( and remembered ?) knowledge thrown in, so I am in for a better explanation. Cheers, Max. Edited January 12, 2022 by Max Z Quote Link to comment Share on other sites More sharing options...
Max Z Posted January 12, 2022 Share Posted January 12, 2022 My Atom, ready for it's next flight, hopefully more successful than the last one. Traces of repairs everywhere, but not visible at some distance ? 3 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted February 18, 2022 Author Share Posted February 18, 2022 (edited) Sorry Max, I missed this one, looks as good as new! Edited February 18, 2022 by Richard Harris Quote Link to comment Share on other sites More sharing options...
Steve Adams Posted February 20, 2022 Share Posted February 20, 2022 Hi guys, I'm absolutely smitten with this little Atom autogyro would there be anyone kind enough to be able to send me a photo copy of these plans please? I'd gladly pay costs as looking through my many back issues of RCM&E and others I can't find the plans,for which I'm certain I did have ? Many Thanks In Advance Steve Quote Link to comment Share on other sites More sharing options...
Caveman Posted February 20, 2022 Share Posted February 20, 2022 Steve, pm me your email address and I'll send them today. GDB 1 Quote Link to comment Share on other sites More sharing options...
Max Z Posted February 20, 2022 Share Posted February 20, 2022 (edited) On 12/08/2014 at 13:16, David Ashby - Moderator said: It'll be a build article and plan in RCM&E's 2014 Special Issue that's out mid-Sept It was not an add-in free plan as we are used to, but printed on multiple pages of the magazine. Edited February 20, 2022 by Max Z Quote Link to comment Share on other sites More sharing options...
Max Z Posted February 28, 2022 Share Posted February 28, 2022 My Atom has flown again!!? Two short flights, and two overturns on landing. I have to get in to it again I am afraid, iirc you have to give it a short burst just before touchdown, not just pull up. Oh well, no damage apart from a slight upturned TE at the root of one of the blades, already ironed out. Caused by the blades crossing each other when hitting the ground. A bit more wind than I liked, so it will fly again soon, but not today. 2 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted March 4, 2022 Author Share Posted March 4, 2022 Good to hear you have got it back in the air Max ? Quote Link to comment Share on other sites More sharing options...
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