AVRO 539B scratch build - windy flight.

by alibopo | January 5, 2014 | (4) Posted in Projects

AVRO 539B Scratch Build in flight.

 

This is not the maiden -  I managed that Sat 4th Jan – which, after a few heart-leaps during the trimming-out phase, was very successful. Well the flying was great, but the filming was a washout. I somehow set my camera specs to record in audio mode only. Sound but no video!  :-(

Desperate to get the little beast on film I spotted a brief lull in the winds and ventured out Sun 5th Jan. By the time I got to my flying site the calm spell was just finishing and the wind was on the rise. Just time for one quick flight before it got too scary for me!

This plane can fly MUCH slower, but that doesn’t cut it in these winds.

UPDATE 02/03/2014; the plane had a 1700KV 28A motor to start with, but current draw was quite high with the 9x3.8 prop I was using. Time in the air wasn't really that good. I tried a smaller prop, 8x4, to allow the motor to use its revs to produce the thrust - hoping for more efficient use of the motor - but I think too much thrust was lost pushing air against the blunt nose. A bigger prop pushes more air out beyond the blunt nose, so not so much thrust is lost. With all that in mind I decided to try a slower revving motor, better suited to turning a bigger prop. I went for an EMAX GF2215/20 1200KV which theoretically draws about 20A with a 10 x 4.7 slow flyer prop. I only had 9 x 4.7 prop around, so tried the plane with that. It flew fine, with plenty of get-up-and-go for the take-off. I'm guesstimating my max current draw from this 'under-propped' setup is somewhere around 15-16A. This should give me much better flight times, though I've still to get a chance to confirm this. Last outing, with the new motor and prop, shortly after I got the plane in the air the wind picked up and I was happy (relieved) just to get it down without mishap!

COMMENTS

Art on January 5, 2014
Looks really great up in the air - you rotten dog - with your flyable weather and stuff - its going to be about -10 here in Wis with about -40 wind chill - I can't get my fingers to work in that kind of weather - I don't know if the bats would even work. I have been playing around with a Neuport 11 'way off scale' plane - you should make one of those so I can copy your success rather than my failure :) I lengthened the tail moment and nose moment based on Cunningham's biplane guides but have not yet been able to try it - it's winter here in Wis, USA.
Love your articles - keep making planes and keep posting them - later - art
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alibopo on January 6, 2014
Hi Art, thanks for the comments. Roll-on the better weather is all I can say. We don't have the cold (usually snows Jan/Feb/March) but we've had a series of deep lows crossing the UK for about 3 weeks now. Lots of gales, with peak winds around 80 mph; a lot of rain, coastal tide surges and flooding in vulnerable areas. We're lucky - no flooding around us, I'm in Portobello, just outside of Edinburgh on the East coast of Scotland. For flying, I keep an eye on two different weather websites that display predicted winds on an hourly basis. Give or take an hour, they're usually pretty reliable. Both of my weekend outings were when the centre of the low (eye of the storm) passed through. But the next two weeks are just wind, wind, wind - which is why I risked it on Sunday. I had a look at some Neuport 11 images on Google - I see plusses and minuses for modelling in foam board. The slab sides are a gift, I suppose the swept top wing will be quite easy, narrow bottom wing not so easy (a bit weak maybe?). Scale tail surfaces look plenty big enough to give authority. Biggest problem I see is the snub nose, but you've countered that with stretching the fuselage. If I hadn't been so taken with the AVRO I think I would have gone for the SE5a. I reckon it's an ideal choice for a model - it's got the length front and back to be well mannered and balance without too much dead weight on the nose. And those slab sides and nose would be easy to recreate. Looking at my build, it is pretty compact with short moments - which can make it quite a 'busy' little plane. I found the elevator reaction VERY positive, even on small throws. In lighter winds it was looping in its own length! Once I got the throws dialled down, with plenty of expo, it became a lot easier to fly. It does have quite a big horizontal stabiliser so once it settles it's rock steady. I think some of the older articles on RC focus so much on stability because they didn't have access to modern transmitters - not just trim buttons, but expo, dual rates, and the ability to alter throws without touching the plane's mechanics. Maybe not obvious in the video, but I've increased the wheel size. Even in soggy Winter grass I manage a ground take off and very few nose-overs on landings. I'll have to get some paint on it now, plenty of opportunity over the next few weeks! Cheers, Ali.
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Bedrock on January 9, 2014
I tried to fly on one of the very rare recent flying days down here in Wiltshire. 2 mins to the local field, walked across the soggy football pitch, plugged in battery and tested controls. All ok except throttle would wind up to half power then cut off. Spent a cold 20 minutes trying to get it to re-calibrate until I noticed that it was the connection on the engine side. It looked ok until the vibration picked up on applying throttle. Been way to windy ever since, although this weekend is looking better....
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alibopo on January 9, 2014
Ouch - that was frustrating! I follow Josh Bixler's advice and take a couple of planes when I go flying. Even if I have a disaster with one I can usually get some flight time with another. I've a couple of reliable 3 channel builds - the FT Flyer with a decent battery load manages a bit of wind, as does my modified Old Fogey, either in single wing or biplane mode. I'm hoping for a chance to get out this Sunday. Cheers.
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AVRO 539B scratch build - windy flight.