Christmas Curare EP

Thanks for that, Phil. It's interesting to note that my Blue Angel airframe, built using 1970's techniques (thick planks of balsa and a foam wing), is just 78 grams heavier if we used the same battery. I think that most would assume that a modern laser-cut airframe would be a lot lighter.

Mike

After it's maiden on Sunday last thanks to Jon although I think Mike was itching to have a go some tweaks and adjustments need implementing. CG could do a little move. Judging by the trim settings a slight mechanical adjust on the ailerons. Rudder is a bit more though, showing up on the vertical.. Jon thinks it may be more speed required or some motor thrust line adjustment.

Easiest route is to increase speed. The prop used was 12x6 which pulled around 50 amps static. Initial prop at time of building was 12x8 but this pulled over 60 amps. Today, Wednesday 16th December Santa arrived with some props, one of which is an APC-e 11x10. Without to much ado it was reamed and balance checked - perfect. Time for another test.

A 6 cell lipo 4000 maH at 96% capacity, Firsr run-up to half throttle gave readings of 28 amps / 685 watts. Idle back for a moment then wind it up to WOT. Reading was 61.5 amps 1220 watts. Did this twice and not much variation of readings.

Unplugged LiPo from the ESC but left the meter connected which now scrolls thought last readings. Battery volts 24.11 (82% cap); Amps Peak = 64.5; Peak Power = 1311 watts; amps used = 364 maH. These figures are at a static test so some unloading of current should bring drop in current. Just how efficiently the prop uses this power is yet to be tried out. :whistle:

<em>As a footnote: This same motor fitted in the Wots Wot running off 5 cells and 13x8 prop developes 1200 watts at around 60 amps. It certainly hauls the heavier draggy biplane around easily</em>.

PhilF51 wrote: Rudder is a bit more though, showing up on the vertical.. Jon thinks it may be more speed required or some motor thrust line adjustment.

Just to be clear, yaw tracking in a vertical is nothing to do with speed, it needs a side thrust adjustment, what I said was that you need to get the right prop for it first before we can fine adjust the side thrust, as prop choice has an effect.

With the 12x6 it flies too slowly (as predicted ) which is particularly noticable on the vertical lines.

Hate to say I told you so

JonTappin wrote: Phil
6" pitch won't be much good, this model needs a bit of speed, you need less diameter and more pitch 8-9" is what I would be looking at, obviously go down on diameter though.

Thanks Jon. I think my text is slightly ambiguous, leading to a misconception of wot I ment! :lol:

I've been flying with a 11x8.5 for many flights but did try a 12x10 the other day for one flight. Current was 80A and the vertical was better than it was with the 11x8.5. Speed in level flight seemed about the same. When I got home I looked at available APC props and will be getting a 11x10E soon and might also try a 11x9 (not electric). Good to know that the 11x10 was still in the 60's for current because I don't really want to be running at 80A because (even with throttle management) the flights are going to be a lot shorter than at 60A.

As for me itching to fly it...the truth is I was itching to see it fly. I offered to fly it at about 10.30 and it didn't fly until well after lunch. I'm also keen to see YOU flying it...there is no point in buying all these models if you revert back to flying the orange foamies and a Wots Wot all the time!

MikeSeale wrote: I'm also keen to see YOU flying it...there is no point in buying all these models if you revert back to flying the orange foamies and a Wots Wot all the time!

What he said