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Old Apr 16, 2012, 12:55 PM
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United Arab Emirates, Abu Dhabi, Abu Dhabi
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Thanks Dereck,
I have set the lower spar at about 2.25" so the c of G should be alright by the sound of it.
Also sounds like my throws are about the same, though I may have a tad more elevator throw.

I had a 7 x 3.5 but really don't like the orange weedy prop so I changed it to the 8 x 3.8 sf which I know works well on the motor battery combo I'm using on a similar sized and weight model.

The wattage should be loads less than the 10a esc fitted.

sparks
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Old Apr 16, 2012, 03:45 PM
Visitor from Reality
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At least the APC props are a reasonable colour, though it could be argued that bright orange is somewhat safer if you have any folk around who don't know about propellers...

Sounds like you'll have plenty of grunt up front. I did check my set-up's wattage - vaguely recall that I estimated the model was flying in 'scale-like' fashion on maybe 40 - 50W. I won the motor in a model meet lottery, so all I know for certain is that it was silver in colour and fitted!

Oddly enough, my CG was on the mainspar too. Even doing scale models, my design/build habits don't change much.

Biggest problem your ESC will have is boredom

D
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Old Apr 21, 2012, 03:57 AM
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United Arab Emirates, Abu Dhabi, Abu Dhabi
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I took the Raven for the maiden this morning. Got my thumbs warmed up with the little Microsquire then fitted the lipo and gave it some operational ground checks and centred the controls.

Tried a hand launch and it went away well initially but soon was sloping away and sliding to the left. I shut the throttle and holding right elevator put her down a little untidily but without damage.

I added more right rudder trim and tried again but the result was similar.

Thinking the roll tendency was torque related, I added a smidge more right thrust and thought I'd try a take off from the sand. A lovely steady straight roll and gentle, straight takeaway ..followed by more rolling to the left and me trying to land without breaking anything.

Checking the alignments I noticed that the washout that I had built into both wings was still there in the left, but the right wing was totally square! Hadn't noticed this after the covering, oops.
Now added a little washout to the right wing so hopefully the next time out I'll have better success.
Watch this space.
sparks
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Old Apr 21, 2012, 05:03 AM
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Yep Sparks, always check the warps! I made the same mistake with the Spartan which was dead straight when checked, but after waiting for two weeks for the weather it wasn't.......I got away with it too! better luck next time, I'm sure it will be OK.
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Old Apr 21, 2012, 10:59 AM
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sparks59's Avatar
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I'm fairly confident it will be alright George, It really did take off fantastically smoothly and tracked nicely straight before the lift gently picked it off the ground, fingers crossed!
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Old Apr 21, 2012, 11:44 AM
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Photos from the 'field'
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Old Apr 21, 2012, 12:17 PM
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Good going Sparks. Those lightweight wing structures are not all that stable - you could have lost that washout driving to the patch. Sort that out and she'll fly fine.

Now, don't ask me about the Raven 3X...

D
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Old Apr 21, 2012, 12:17 PM
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She looks great! Sorry about your maiden woes, but it sounds like a minor problem. I'm keeping my fingers crossed for the next attempt! Good luck
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Old Apr 21, 2012, 12:29 PM
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Quote:
Originally Posted by Dereck View Post
Good going Sparks. Those lightweight wing structures are not all that stable - you could have lost that washout driving to the patch. Sort that out and she'll fly fine.

Now, don't ask me about the Raven 3X...

D
Quote:
Originally Posted by owlsabie View Post
She looks great! Sorry about your maiden woes, but it sounds like a minor problem. I'm keeping my fingers crossed for the next attempt! Good luck
Thanks guys.

The wing has been sitting around covered for weeks, waiting for me to finish the rest. Should have checked it more closely for sure. I built the wing with an extra spar, but maybe I should have added another one or two just to keep it tight. Anyway, we will see next weekend unless I get the chance on an evening this week.
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Old May 05, 2012, 04:12 PM
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The blackbird flies..

Raven Maiden.wmv (5 min 14 sec)


Maybe a little erratic (what do I mean little!)

Still needs a little more attention to wing shape. I think more dihedral would have been better

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Old May 05, 2012, 04:23 PM
I like real wooden aeroplanes!
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Didn't look too bad Sparks if we ignore the "landing"! Does it tend to "latch" into turns and need a bootful of opposite rudder to roll it out? Also looks as if it may be a just wee bit tail heavy. May I suggest that you try warping a bit of washout - 1/8" to 3/16" - into the tips and adding a tad of lead up front? Easier to try that first before considering more dihedral.

Lots of sand, but at least there are no trees to avoid!
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Old May 05, 2012, 04:48 PM
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Cool stuff! Very pretty in the air
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Old May 06, 2012, 03:46 AM
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Thanks Owl. It look a lot better on the video than from behind the TX, I didn't feel like I was totally in control for most of the flight, more like crisis management for much of the time.

Sundancer, your comments are spot on, the CofG is about right with the calculated numbers that I fed into the online software, but I had exactly the same thought. It has a slight tail heavy attitude and it climbs away with no encouragement. The main reason for having my friend shoot the video was so I could review the flight properly later, which serves as a good record to sort out foibles etc.

You probably noticed the 'porpoising' when I was trying to come around and line up for a straight landing (clearly without success, but i was a relief to get her down even if the wing load exceeded the marginal magnet strength). I agree with your comments that a little extra nose weight would be in order to sort this.

The other thing that I have to check it the incidences. The tail should be fine per the plan, but I think I may have inadvertently increased the incidence a tad while tweaking the wing fitting- note to self CHECK THIS!

You description of the turns is also about right, needs a bootfull of rudder (I was flying it on low rates this time) to turn in, and a bigger bootful to pull it out again. With the obvious problem of getting her back to straight and level.

I had sorted the previous wing problem and put the washout back in and they were the same after I corrected it, but after it had been sitting in the heat for a while post flight, I notice that there is a slight differential there - not helpful at all. I will check, but there was about 1/8" washout in originally so maybe i'll add a little more and retighten the litespan covering to hold it in place.

Still the take off was pleasant, it virtually lined itself onto the wind and rose off gently as the pressure differential increased.

sparks
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Old May 06, 2012, 04:05 AM
I like real wooden aeroplanes!
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I'm sure you will tame it Sparks, just a matter of "keep on tweaking" until it feels right. I imagine that wings moving about as the covering - any covering - is subjected to your extremes of temperatures is always going to be a problem, it is here in the summer and I try to avoid having models sitting around in the sun and always recheck the wing line up before each session. I didn't do this on my Spartan after it had been waiting for suitable weather for a couple of weeks after completion (it was straight then), a warp crept in and I was lucky to get away with the first flight which finished up in a tree!
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Old May 06, 2012, 04:49 AM
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Correct George.

It was 44degC yesterday around midday and early afternoon, although it was probably not more than 37 while flying. It is a lot for the covering to take and the heat shrinks generally get a bit baggy. My Popsie and the other Solarfilm covered planes always seem to be ok, however the covering was not as tight yesterday. I think the solite / litespan don't pull quite tight enough to keep things in check. The old doped tissue wings are generally unaffected!
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