Richard Harris Posted August 4, 2011 Share Posted August 4, 2011 A few years back I started playing with a 'proof of concept' model of the Fairey Rotodyne, very basic but it did get up into the air eventually. The model ended up being a tad on the heavy side which meant that I needed more powerful motors/ servos/batteries etc, Something which I couldn't afford, it ended up getting bumped has ended up in the 'corner of shame' in my shed. This is the Fairey Rotodyne promotional video, what a great piece of British engineering. And this was my poor attempt..lol Anyway, I got thinking today when I found two 10 amp ESC's. Would it be possible to build a smaller version. But this time make it a little scaler and have a fixed head. But instead have elevons for pitch and roll? and keep it cheap and light. So my question is, can anyone suggest a good cheap out runner that is with in the limits of my ESC's? I thought I could scale it around the motors (props). I think I have an 800mah 3 cell lipo I could use to power 2 motors. Rich Quote Link to comment Share on other sites More sharing options...
Pete B Posted August 4, 2011 Share Posted August 4, 2011 Something like this Towerpro 2408-21, Richard? I use one in my little 40" Cub. On 2S with a 9 x 6 it draws about 12A, so 3S should bring that within your ESC limits. Cheap as chips, too! Pete ps a few figures about the motor in my thread about the Cub here. Edited By Pete B on 04/08/2011 23:03:44 Quote Link to comment Share on other sites More sharing options...
Cyclicscooby Posted August 5, 2011 Share Posted August 5, 2011 Nice first attempt.. I thought you said it didn't work very well.. !! Luv Chrisie.. xx Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted August 5, 2011 Share Posted August 5, 2011 Posted by Cyclicscooby on 05/08/2011 03:50:58:Nice first attempt.. I thought you said it didn't work very well.. !! Luv Chrisie.. xx My thoughts exactly! Bet it was quieter than the original too! tim Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted August 5, 2011 Share Posted August 5, 2011 Great. I love to see people experimenting and more so when it is sucessful. That first version was really great, it looked convincing, it performed beautifully and should never have been cast aside. May I suggest that a little investment would be well worth while. This should make a fascinating plan in a magazine. Go for it Quote Link to comment Share on other sites More sharing options...
Erfolg Posted August 5, 2011 Share Posted August 5, 2011 Is a fixed head, the same type as all the indoor helicopters, that cost about £20-30? With a large capacity drive train and electronics from one of those types it could be relatively easy to build and fly. It is strange with hind sight, how obvious the noise was an issue, which should have killed the concept early on, as minor reductions would not be sufficient, for both regulators and the public. Yet with hindsight the Bristol Belvedere could have had a commercial future with good management and encouragement by the then Government. Anyway I look forward to seeing your new model, or even a re-engineered old model. Quote Link to comment Share on other sites More sharing options...
Cyclicscooby Posted August 5, 2011 Share Posted August 5, 2011 Ironically, I was in Hereford Model shop yesterday, checking out the massive range of Airfix kits, and came across this aircraft.. Never seen one before... Then I come on here two hours later, and your making one... ACE... Same happened with the Wittman Tailwind, and Pete's plans, so it must be fate that I build one of these 'machines'... I'd love to know how to make one (Rotor disc size, wing length, etc... ) so don't stop as its a mad little thing.. Luv Chrisie... xx Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted August 5, 2011 Author Share Posted August 5, 2011 I have read that the Fairey engineers worked on trying to baffle the sound on the tip jets but I think it wasn't a great success.They were also worried that as it transitioned from 'the cruise autogyro mode' and relit the tip jets that they would fail. But I dont think they ever did and I am almost certain I read that it would transition into hover with one out. The fuel was supplied up through the rotors and the centrifugal force from this pressurised it as it got to the jet burner. Compressed air was also supplied to the jets, this would mean a fuel and air supply through some kind of joint at the hub! that was an engineering feat on its own. Using the tip jets it eliminated the torque effect on the aircraft, I think the yaw control was done through the variable pitch props. Simple but extremely clever! Mine will just be a simple version, I am thinking of going down the depron route. I hate the stuff! but I am sure I will be able to produce a light airframe. Will just see how the design progresses. I was never really happy with my first attempt, it was sluggish in roll which meant me having to purchase some 20kg servos. I just could not justify this, but I did have big plans for it including a scalish head that I machined up. The reason for the first go was after a chance meeting with Jim Morely, he had build a heli version years before. He had made a set of plugs for his and made me a set of vac formed moulds off these for me. Unfortunately he passed away a few months later and I never did get to send him the dvd of the 'proof on concept model' flying which I had promised. Maybe one day I will get back on the larger version. This is a better video of the start of the project flying on a 3 blade rotor, it did fly a lot better with a 3 bladed rotor. My old friend Derick is videoing (the one with the yellow Tiger moth at Greenacres) he likes talking to himself!..lol Rich Quote Link to comment Share on other sites More sharing options...
Cyclicscooby Posted August 5, 2011 Share Posted August 5, 2011 he likes talking to himself!..lol He does doesn't he... LOL.... Thats making a different noise than I was expecting... A kinda mix between a Heli n plane... ! I guess thats not suprising, as thats what it is.. !! LuvChrisie.. xx Quote Link to comment Share on other sites More sharing options...
Erfolg Posted August 5, 2011 Share Posted August 5, 2011 Richard I guess it is not that long ago you built it? If it is a long time back, I guess it was using Nicad batteries? Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted August 5, 2011 Author Share Posted August 5, 2011 Erfolg, It was a couple of years ago, as soon as I tried to up the power from 3s to 4s it wouldn't fly due that bit of extra weight and crashed. The mast snapped off, UC broke and 2 of the 4 blades were destroyed. So it was put to one side, the wing is about the only thing un marked. Rich Quote Link to comment Share on other sites More sharing options...
Steve Adams Posted August 5, 2011 Share Posted August 5, 2011 Hi Rich, Your model flys really well! It would be fantastic if one of the in house prolific designers that we have here,to make a nice scale Rotodyne,and sent the plan in to RCM+E ......question is who would be up for the challenge? As all of the designers are all good at what they do,thats what i like to see something that breaks the mould,inovative,and british absolutly fantastic!! Regards Steve. Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted August 5, 2011 Share Posted August 5, 2011 Hi Rich. I am with Peter and the other posters on this one ,its a really enthralling model that flies at a scale like speed ,and with great presence ,i don't think a smaller version will have the same appeal . A model with that sort of authority is probably power hungry is that whats holding you back ? I love it don't leave it in to die as a hanger queen. Tom. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted August 5, 2011 Share Posted August 5, 2011 Richard I assume it was Nicads then, that were successfully used? What does confuse me though, is I thought Lipos had a higher power density than Nicads. Or did you want extra duration and went for more capacity? A scale width body will hold a multitude of batteries and electronics I am not clear if you intend going the helicopter route or staying with auto-gyro. I have seen a video of a large Osprey flying successfully with the tilting rotors. Rather than the indoor models we can buy. On that basis, the Rotodyne could be easier? I can see you have the metalworking skills to build a precision set of mechanical's. I just cannot work out how you can do a scale type rotor drive. What is the plan and concept? Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted August 5, 2011 Share Posted August 5, 2011 Posted by Steve Adams Your model flys really well! It would be fantastic if one of the in house prolific designers that we have here,to make a nice scale Rotodyne,and sent the plan in to RCM+E ...... Steve. There are no "In house" designers. WE are all freelance modellers who just design what we feel like flying. Quote Link to comment Share on other sites More sharing options...
Cyclicscooby Posted August 6, 2011 Share Posted August 6, 2011 I'd start with a 400 size heli. You have the rotor drive, with a one-way auto bearing, so the head will still rotate once 'heli' mode is over, plus, you have full cyclic control to use or not, that has to be better than an auto-gyro tilting head. Altho, thinking about it, you probably need a tilting head, not cyclic..!! You could put a UJ ontop of the orig main shaft, adding the head onto this, which would allow a powered tilting head.. OR... complicate it, by keeping the cyclic control and actually tilting the whole heli frame back for plane mode..!! With the tail removed the frame will be narrow and short, and a good base to build a plane around.. Of course if you do have a powered head for proper VTOL, you'd have to add a gyro to one of the props (which side would depend on rotor direction) I imagine.. ??? The props will probably be ticking over already, but if they're both doing the same thing, I dont think you'd get much assistance regarding torsional rotation.. It should be possible to turn the gyro gain down then off when transitioning between the two modes, but unless this can be programmed into the Tx, it'd be a handfull.. Just my two peneth, but i've been up for 20hrs now, so im probably talking jibberish.. Luv Chrisie.. xx Quote Link to comment Share on other sites More sharing options...
Cyclicscooby Posted August 6, 2011 Share Posted August 6, 2011 Forgot to say.. NICE MACHINING.. Quote Link to comment Share on other sites More sharing options...
Steve Adams Posted August 6, 2011 Share Posted August 6, 2011 Sorry Peter, What I was Meaning by "In House Designers" Was regular contributers like yourself TN,LT,TH Etc....Now i stand corrected!! Humbled Steve. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted August 6, 2011 Share Posted August 6, 2011 No need to feel humbled. I just wanted to make sure that everyone knew that we are amateurs just like everyone else. Some of us have more time and are definitely more obsessed with what we do. but that is all. Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted August 9, 2011 Author Share Posted August 9, 2011 I did a google search and found a 3 view drawing of the Rotodyne, this I have blown up to suit roughly the motors I have now purchased from the Big fish. Blue wonder? never heard of them but they are rated at 8 amps and are said to produce 400 grammes of thrust each. The hardest part is going to try and keep it light, my head is telling me to construct it from foam/depron but my heart is saying balsa bash it! I am looking at around 800 grammes AUW which I think should be manageable just? I will have a think about how I will construct it over the next few days then try and make a few sketches. As nice as it would be to have it being able to take off vertically I don't think I have the ability to be able to achieve this, so mine will just be the autogyro version. Rich Quote Link to comment Share on other sites More sharing options...
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