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Chilli Breeze from Sarik Plan, Electric Conversion.


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Well today was surprisingly sunny and nice.

So I went flying. And didn't crash! The new motor mount is great - no signs of anything untoward, so I can make a cowling now. I only got one flight because I lost a wheel on landing and I didn't have any spare collets / star washers with me but I learned a few things and am very pleased with the outcome so far.

As for the flight and assessment thereof: I used a 10x6 prop and that seemed fine certainly enough for today: I may investigate more powerful possibilities later but I would like to fly a lot more first.

Still dragging the tail around a little on aileron turns, but I expected that - it's a pattern ship and requires flying rather than just steering, if you see what I mean. The differential has certainly helped and it's really rather graceful in the air. CG seemed a little forward as I ran out of up elevator on flare for landing but nothing terrible, I will try it 5 mm further back next time. Nice and responsive to all controls too.

Take off was long but then so was the grass - the moment it hit a short patch it was off, having cut a short swath across the longer stuff.

So yes, really, really pleased with it. First PROPER plan build since 2003, only my second aeroplane after an eight year ( or thereabouts ) break.

if I build a second - which is pretty likely though there is one thing I will ensure I do.

Yep, put the undercart on the wings.

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Well done Stuart, worth the effort. yes.

If you do experiment with different prop sizes and pitches one of these can be useful, as you are a bit in the dark without one. Although the acid test is in the flying, keeping an eye on the amps can keep your motor, ESC and battery, young and beautiful!

Edited By Piers Bowlan on 29/04/2019 08:06:52

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BTW, re: 10x6, if you can pull up into a vertical, roll, then a nice half loop to vertical down, you have enough power...

 

re: CG and differential, the following is copied from a F3A trimming chart:

 

3. Centre of Gravity (Method 1) Roll model into a near vertically banked turn

A. Nose drops
B. Tail drops

A. Add weight to tail
B. Add weight to nose

(Method 2) Roll model inverted

A. Lots of down elevator required to maintain level flight
B. No down elevator required to maintain level flight, or model climbs

A. Add weight to tail
B. Add weight to nose

 

5. Aileron Differential

(Set the model up with 12 Degrees up and 11 to 12 Degrees down as a starting point.)

Fly the model level and into any wind, going away from yourself. Pull it up into a 45 Degree climb and roll to the right. (After adjusting, try again in both directions)
A. The model does not veer sideways.
B. The model's path veers to the right.
C. The model's path veers to theleft.

A. No adjustment required
B. Increase differential, increase the up throw on both ailerons
C. Increase the down throw on both ailerons.

Edited By Nigel R on 29/04/2019 10:09:42

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  • 2 weeks later...

Hi folks, one last update on this from me: the CB is fully tested and trimmed and flies superbly now there was not a great deal to do really except adjust the aileron travel with some differential, ( up on both sides ) add a little weight to the tail and it was all sorted: Nigel - thanks very much for the guidelines I MAY put in longer landing gear as our field can get a little shaggy and the CB really is very low down, but - surprisingly to me, yesterday I found out that a hand launch is something she will climb very happily away from. The 10x6 certainly seems fine, but I will slap on a 10 x 7 for comparison and see if there is a bit more vertical with one, but the current prop pulls fine as is. Also now that I am happy with the flying qualities ( very happy) I will put a cowl on it and a number in the roundel on the stbd wing. .

Here is is yesterday after a lovely flying session: ( See what I mean about being REALLY low?) dscf0001 (3).jpg

Once again folks, thanks for all the help and encouragement - you all rock.

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Hi, where did you end up with the CG? I think mine is still nose heavy - I had to ad quite a bit to the tail and it still needs some elevator to keep it level inverted.

I do find mine is hard to keep track of as there is not much of it to look at particularly in profile, so in dull conditions or if it gets a bit far away I have to concentrate extra hard.

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Stuart, no problem, just a copy and paste on my part there.

will-o, a little down is ok, although it depends how much "a little" is, the lightest of pressure on the stick would suggest you're in the right zone.

As well as the two methods noted above, a power-off dive at 45 degrees can tell you how close the CG is - with a correct CG the plane should neither pitch up nor tuck under, if it pitches up CG is forward, if it tucks under then CG is too far rear.

I'm almost certain my larger Wind is balanced as per plan location, and the marked location is spot on. It will happily enter a proper flat spin, yet is also still nicely behaved at slow speed (and passes the above tests for CG position).

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