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I’ve been pondering designing my own RC plane for a while, not completely from scratch mind, but a scale job. Sports-scale probably better defines my intentions, I’ve neither the time nor patience to spend hundreds of hours on reproducing a scale model in minute detail. There have been a couple of free plans in the mags recently (Tims Airspeed Courier springs to mind) of about 60" span with electric power, which have got me thinking.

Over the Christmas period I took my son to the RAF Museum at Hendon, while wandering around one of the halls a little aircraft from the thirties caught my eye, a Miles M.12 Mohawk. I thought this was a pretty little plane, looking nice in the orange and black colour scheme. Looking it over for a while I started to think this might make a nice scale candidate. There was nothing too awkward about the shape, nice tapered (but not too sharply) wings, a reasonable length nose. Hmm, maybe this would be the one chose.

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On returning home I did some digging and found a bit more information on Wikipedia, and a little 3 view here (Broken link ~~http://home.comcast.net/~aero51/html/gallery/m12.htm~~). That’ll do to get me started, I also wanted to practice using CAD, so it was decided then. First step I wanted to do was trace the 3 view into CAD, from there I could scale it to whatever size felt appropriate and then start to work on the internal structure.

The specs of the original are as follows:

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  25.5 feet
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  35 feet
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  183 sq feet
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Having done a bit of maths, 1/8 scale would give me a span of 53 inches with a wing area of 412 sq. inches. That feels about right for the same power plant that Timused in the Courier. 1/7 scale gives 58 inch span with an area of 508 sq inches, I might end up going for that, I want to chat to some people first, to see what they think.

So anyway, to cut a long story short, in a few spare moments over the last week, I’ve traced the 3 view. Its pretty complete, a few of the curves need a little work if you zoom right in, which I’ll try and tidy up to the point I’m completely happy with. There is a png of the cad file below if you are interested.

You can click on any of the images on this page bigger versions, if you want the full size of the 3 view below, click here.

 Thats all for now, I want to do a little tidying up and then start thinking about the internal structure.

Always forget this bit:

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

Speficially needed if you are using a Linux box, shared by Apple Talk.

From here (Broken link http://www.nextgengeek.com/2011/03/05/howto-use-linux-as-a-networked-timemachine-volume-for-your-mac/) in this instance, although there are loads of howtos.

Flew the merlin for the first time on the 1000mah lipo. Had a 13 min flight on half power and less, all great. Then a second of 10 mins on mostly half to full power, still plenty of life left. When I got a chance to charge it, a reported 513mAh went back in. So that probably means I could get a good 35-40 minute flight out of it, very happy with that! Also had a try of inverted flight with some success, at altitude mind! It was a bit gusty but she appears to be happy inverted, will try some more the next time out.

Wind was 5-6 mph max, tried the Weasel but there just wasn’t enough lift. Thankfully only a short walk to get it 🙂

This was my autumn build for 2011, a pretty little aircraft which will hopefully be a delight to guide around the sky on a summers evening. I’ve put some details of the build up on a dedicated page here.

So I finally got round to flying this, it was a short and eventful flight! I knew it was a little tail heavy but , but only 1/4" or so behind the indicated CoG on the plan. I figured it might be a bit of a handful but with the large elevator I thought I would be able to manage it. How wrong I was, quite an exciting minute or so followed after a hand launch eventually ending her coming in hard from about 20’ up.

Amazingly the damage was slight, the planked cowl I took so long over was smashed, the prop had gone and the motor mount had sheered off the firewall. One wing had a chunk out of the LE and a couple of the fuselage longerons had suffered. In all honesty I could have repaired it, perhaps I should have repaired it, but I decided to rip out the electronics and bin the airframe.

It had annoyed me ever since I noticed I’d built a banana of a fuselage and then to compound it my dodgy wire bending left it with a wonky undercarriage. She was a wrong ‘un from the word go!  The poor thing sat around my office getting bumped around whenever it was in the way; very much un-loved, so now its gone. Onto the next thing!

So its maiden flight wasn’t without drama, however it has survived and has been aloft four times now. Loving flying it, I’ve pretty much got my box circuits down, and I’ve done a couple of take offs and landings. Need to practice the figure of eights a bit more though!

I’ve made a page for it here.

Partly because we are having a general tidy up in preparation for the new baby and partly because I want to raise some funds for a Blade 450, I’ve decided the HPI Savage has to go.

I’ve tried starting it a few times recently and got it running, but as soon as I throttled up it stalled. I’d pretty much given up with it when I had a brainwave: send it to Peter down at 308 Holloway Road and see if he could make it work. Turns out after a bit of heads scratching he found a speck of dirt in the carb. No it’s running sweet, already to go up on eBay tomorrow.

One last video of me testing it after I got it back this morning.

So after nearly a year of sitting around unused, its gone on ebay. So long Easystar, I had fun flying you. More info here.