Jackdaw

[Pchristy]

Thanks all for the replies and suggestions! As I said, using a propo Tx is just a stop-gap until I get the Variophon finished All my time has gone into the model so far, but now that's finished I can get on with the "proper" Tx for it.

Ron: I've built servo reversers in the past using a single CMOS chip, but as I've been tight for time, I went the easy route this time. I'm now regretting it!

Mike: Thanks for reminding me about my reversers! I only went the "easy" route because time is running out, and I want to get it finished, run-in and test flown well in advance of Ponty!

Its chucking it down here this morning - no flying today - but the forecast for tomorrow is calm and dry, but COLD! After that the wind picks up again, going in to next week. Is winter ever going to end?

I've put some pix of the Jackdaw up on the RCM&E forums. Those forums are always full of people modifying Super 60s to take ailerons. Don't get me wrong - the Super 60 is a fine model, but it was designed for free-flight, with occasional radio interference! To make it suitable for full-house control involves reducing the dihedral and adding ailerons. Why bother, when the Jackdaw is of a similar size, less "floaty" and has all those features designed in from the start?

The Jackdaw is a much over-looked model. Time to put that right!

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Pete

[Mike_K]

Morning Pete

Thinking back I had already modified Phil_G encoder software to reverse the throttle for a friend who had done a conversion and had exactly the same problem as you.

What I did for him was add some code to see if inputs D3 and D4 on the Arduino were linked. If no link is fitted it works as normal, if you fit a 0.1" jumper across D3/D4 it reverses the throttle. If you have one of the DIY-more type Arduino's or a standard Nano on a break-out shield you already have headers fitted to D3 and D4, so you don't even need to do any soldering, you just need a 0.1" jumper that only cost pennies or can be "borrowed" from some other electronic equipment. And it is easy to revert back later, just remove the jumper. I've just grabbed an Arduino and fitted a jumper to show you what I mean.

Cheers

Mike

[Pchristy]

Thanks Mike! I was wondering if it would be possible to program a hardware defined reverse, as the usual "hold the stick over at power on" won't work on the throttle.

I think my Classic Tx has the original style arduino board in it, but it probably has the same headers connected. I'll check later today.

And thanks for the updated code!



UPDATE: The Classic Tx had one of the original Arduino Nano boards mounted on the DEEK-Robot motherboard. That made it nice and easy to program up a new Arduino and just plug it in, without disturbing any of the wiring! The only slight snag is that on the DEEK-Robot board, there is a gap between D3 and D4 pins. Luckily, a Spektrum bind plug is a perfect fit. It is very close to the buzzer though, and since D4 is only providing zero volts, I turned the bind plug through 90 degrees and coupled D3 straight to its relevant ground pin.

This provides the same functionality (ie: it works! ) whilst giving slightly more clearance to the buzzer.

All now up and running, and re-calibrated. Just have to check the controls as they all seem to be reversed as standard! Phil clearly uses Futaba servos, which work in the opposite sense to everyone else!

Many thanks for the mod, Mike! Its a good upgrade!

--
Pete

[Pchristy]

Test flight today was an abject failure! No damage to the model - mainly because it never got off the ground!

I don't know about elsewhere, but we've had three or four days of heavy rain, so arriving at the field, it was no surprise to discover that the grass had not been cut! Not only that, but it was very wet and quite long!

What wind there was was blowing down the hill, so it was a question of taking off uphill - but into wind, or downhill and tailwind. The wind was almost non-existent, but neither downhill nor uphill could produce enough speed for lift-off in the wet grass! And when the tail came up, the model kept trying to ground-loop to the right!

I'm pretty certain this was caused by the prop catching in the long grass and pulling the nose to the right. Going from a 10x5 to a 9x6 helped, but I still couldn't build up enough speed for lift off.

On the plus side, the engine has now had plenty of running!

Next thing is to get some bigger wheels! The ones fitted are 2 9/16" - ones I had lying around. The plan says
2 3/4", but I think 3" will be more suitable for flying from grass.

No flying of power model permitted on Sunday, and more wet weather forecast for early next week, before drying up towards the week-end.

Will have another go later next week......

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Pete

[Pchristy]

The Jackdaw has flown!



Its not over-powered with the ASP 30 4-stroke, and takes a longish run, but once airborne it cruises at half throttle! She tends to swing to the right as the tail comes up, but I think this is the prop catching in the long grass - there's not a lot of clearance!

Ailerons are very docile, with a bit of adverse yaw. I need to add more differential. Rudder is very powerful, with a noticeable nose-drop. I'll need to reduce the throw to fly it on the Grundig "reed" Tx!

Great fun to fly, though!

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Pete