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Tomboy for single channel


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Morning all, our club is going through a bit of a “retro” phase with several old people, myself included, having a dabble. I blame Shaun Garrity and Phil Green. Anyway, having successfully built (and flown) a Quickie Ghost with one of Tobe’s GG actuators and got a bit of an itch to try more, I have now made a single channel transmitter and am building a Vic Smeed Tomboy to try it in. It has a lifting section tailplane and I seem to remember reading that, while good for free flight, not so suitable for radio. Anybody know if it would be wise to change to a flat plate or am I just over-thinking.

 

Cheers,

 

David

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I wouldn't worry. I've built a Vic Smeed Poppet with a lifting section tailplane that flies very nicely on rudder only, although it's a bit over powered with a PAW 55 (That's why the prop is on backwards).

WP_20180410_12_18_40_Pro.thumb.jpg.52517618c05ddb56026bdbdf44b28b2c.jpg

 

Many single channel design, such as the Mercury Matador, flew well with a lifting section tail.

John

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Morning all, just about finished my Tomboy, a bit of sanding then ready to cover. Lovely relaxing build and took me back very many years to a childhood of KK free flighters! The plan I downloaded does not show a C of G position and a quick google didn’t help much, one plan showing about 50% chord. Bearing in mind that this model will be single channel, rudder, kick-up elevator and quick blip throttle, does anyone have any recommendations for a good starting point for the CoG. Thanks,

 

David

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I'll attach the original build article where it states 'the model balances when supported by two fingers beneath the main spar'. I think that's a good starting point. Mine ended up trimmed a few mm behind that but it has proportional elevator control, rather than your kick-up David.

 

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I have just finished a " Vintage Model Company" version of Vic Smeeds Tomboy for a friend with two channel rc and a Mills engine. CG is about 50% chord , looks odd compared to most model I have built over recent years but Vic Smeed designs always fly well, he was a master designer . The prettiest,  JMO is the Mamselle . I built that from plans many years ago with mills power and it flew brilliantly . Still around in a mates collection's might get an airing this summer.

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Thanks for the input, guys. I think start with the CoG on the spar and adjust as necessary. Loved the Aeromodeller article, John, it was a different World, eh? Enjoyed the video, Phil, and it solved the rudder actuation problem for me. I could not work out how to get a pushrod neatly to the rudder now ten minutes on the lathe and I'll have a nice little ali torque rod connector for a servo! Really enjoying this retro R/C diversion.

 

David

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On 15/05/2021 at 09:58, John Lee said:

The plan was published before I was born but I was lucky enough to find a copy of the original Aeromodeller to add to my collection. Here's the cover with an inspiring colour scheme: 

 

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I'm looking at moving house soon so have been sorting out my "stuff" when I came across a box with old Aeromodeller magazines in it, mostly dated late 60's to early 70's. Fascinating reading them again but wondering what to do with them, are they worth anything?

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  • 3 weeks later...

Gentlemen, need some help here. You may have gathered that I have contracted a mild but persistent dose of Retro R/C. It started with the symptoms of Galloping Ghost and has progressed to Single Channel button pushing and I can definitley feel the early signs of Reed Emulation affecting my judgement, I caught it from three irresponsible club members (Roger, John, Gareth, you may well look guilty) who have been spreading it with no thought for their clubmates, abetted by messrs Garrity and Green.

To be more serious, we really take for granted the ability, with modern radios, to trim all the flight controls from the transmitter while the model is airborne. Not so with S/C, so a series of flights and tweaks are required. I have dialled out the persistent left turn, the climb, stall, climb, stall flightpath and found a nice steady mid position power setting for the quick blip throttle. The problem is that full throttle is vastly overpowered, enough to completely disrupt the model's equilibrium, and you can't avoid it as the throttle is sequential, off, mid, full, mid, off. I have measured the mid throttle amps/watts with a wattmeter, reading about 32 watts and have downsized the prop to one (6x4) which draws about 38 watts at full throttle and set the mid position to give about 30 watts. My question is whether the wattmeter readings are comparable across prop sizes, can I expect 30 watts on a 6x4 to give the same performance as 30 watts on a 7x6? Looks a no brainer but I have grown very wary of "gotchas". My flight with the Tomboy this morning was a complete delight, lovely straight climb out at mid throttle, nice positive turns and a cracking glide with motor off, absolutely addictive. I bypassed single channel in my youth cos I could not afford it and by the timeI was working, 27meg propo was here so I bought a Futaba M series (still got it!) and a Super Sixty and have been dabbling ever since, about 65 years of aeromodelling and counting.

Thank for your thoughts,

 

David

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  • 1 month later...
16 hours ago, David Holland 2 said:

Can anybody guess what might happen if you mistakenly fit a reverse direction prop to a Tomboy and then hand launch it.............?  Duh, this hobby has so many ways to make you look an idiot.??

I witnessed a very similar thing at our field many years ago . One of our members was struggling on a cold day to get his Japanese glow motor going. Our then club treasurer , a very opinionated man , was preparing his Mills 75 powered Tomboy for flight. It started first flick whereupon proudly shouted "British engineering at its best" and launched the model. The model promptly came straight back and hit him ! Yes the Mills was running backwards😂. Everybody fell about laughing . He kept quiet for some time after that 

  • Haha 1
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