Peter Christy Posted April 16, 2020 Share Posted April 16, 2020 In another thread **LINK** , Barrie Lever was asking about Peter Valentine's Cox .049 powered "MayFly". That model flew very successfully, although in pre-gyro days, the tail was more than a little twitchy! It was eventually donated to the Goosedale museum, and disappeared when Goosedale closed. Shortly before he died, Peter had started work on another 049 powered model, and I have the chassis in my collection: Power is a Cox Medallion .049 fitted with a Tarno carb (It may be a TeeDee .049 - haven't had a look inside to see!) It should be possible to finish the model off, if i can persuade a metal-working friend to make all the bits, but it will be a long job! Peter also made an 020 powered heli: Because of the difficulty in throttling such a small engine, it was designed to run flat out all the time and be flown on collective pitch. The collective system is pure Bell (no Hiller mixing). Alas, it proved impossible to build a centrifugal clutch that small, that wouldn't slip. When he tried direct drive (no clutch) it proved impossible to start the engine, due to the inertia in the rotor system. An interesting experiment, though! He also built an electric "MayFly", which survives in good condition. Alas, the combination of Nicad batteries and the brushed motor proved inadequate for lift off. However, it should be possible to retro fit a brushless motor, though it will require a bit of re-engineering! (The brushed motor had a built in gearbox). My present project is a Lark Mk2, converted to electric. I'm hoping this will be ready for preliminary run-ups in the garden in a couple of weeks. Full test flying will have to await the end of the lockdown.... -- Pete Edited By Peter Christy on 16/04/2020 11:52:48 Edited By Peter Christy on 16/04/2020 11:54:21 Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 16, 2020 Share Posted April 16, 2020 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted April 16, 2020 Author Share Posted April 16, 2020 Hi Barrie, Yes, its the colour of the plastic housing that's confusing me! I have a TeeDee.049 and a TeeDee.09 - both black. I used to have a Medallion 09 (red), but the medallions didn't have a screw-in venturi. It was moulded into the housing, with a conventional spray-bar. So this is either a TeeDee 051, or a Medallion 049 fitted with a TeeDee housing to take the Tarno carb! Your guess is as good as mine! I think with LiPos and a brushless motor, the Lark should fly OK. I'm hoping to get it airborne on 3S, but I can use 4S if needs be. In the latter case, I may change the gearing slightly to draw more power from the motor for 3s operation. Martin Briggs has made one like this, but his needed 4S. I think he used different gearing to me, though. So far he's only hopped it in the garden because of the lockdown. Mine was a present from my son! He found it on ebay, part built. Unfortunately the builder has made a bit of a dog's dinner of the tail-rotor gearbox, which I will have to dismantle and rebuild. I'm also going to have to make some tail blades and recover some of the other wooden bits. I hope to have it ready for preliminary testing in a couple of weeks time. -- Pete Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 16, 2020 Share Posted April 16, 2020 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted April 16, 2020 Author Share Posted April 16, 2020 Here's some pix of the Lark-E, currently under construction: Haven't fitted the tail-rotor servo yet as I haven't decided how to route the linkage. As it won't have a throttle servo, I have a bit more flexibility in how to mount the servo and route the linkage. I should be able to make it a bit more direct. Still quite a bit to do, and a few things to undo and redo properly! I renovated John Haytree's old Schluter Cobra a while back and converted it to electric. It flies much better like that than it ever did i/c! I'm hoping the Lark will be the same! -- Pete Quote Link to comment Share on other sites More sharing options...
PatMc Posted April 16, 2020 Share Posted April 16, 2020 Posted by Peter Christy on 16/04/2020 14:58:07: Hi Barrie, Yes, its the colour of the plastic housing that's confusing me! I have a TeeDee.049 and a TeeDee.09 - both black. I used to have a Medallion 09 (red), but the medallions didn't have a screw-in venturi. It was moulded into the housing, with a conventional spray-bar. So this is either a TeeDee 051, or a Medallion 049 fitted with a TeeDee housing to take the Tarno carb! Your guess is as good as mine! There's a lot of info on Cox engines here including several rarities. Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted April 17, 2020 Author Share Posted April 17, 2020 That's a really good link, PatMc! I pretty much grew up with Cox .049s, my first powered model being a Cox PT-19 when I was about 10 years old! I've always had a soft spot for them ever since, and still have a couple of airworthy Cox powered models! Another place that is fascinating to visit is the RC Hall of Fame - RC Hall of Fame which tells the story of the development of RC gear, from the earliest days until the end of the American era of dominance. Well worth a visit! -- Pete Quote Link to comment Share on other sites More sharing options...
Mike Sanders Posted July 7, 2021 Share Posted July 7, 2021 Have you finished the Lark yet? Quote Link to comment Share on other sites More sharing options...
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