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Old Jun 14, 2011, 03:34 AM
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latin105fm's Avatar
London, UK
Joined Jan 2009
465 Posts
LIPO question:)

Hi all, quick question. I need to get some Lipos and wondering what to put in my Non built Skywalker..... Going to FPV it and use a 60amp ESC. I Wouldn't might having some power to it and obviously length of flight. Will a 5000mAh 4s be too much?

Cheers
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Old Jun 14, 2011, 05:36 AM
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rcimports's Avatar
South Africa
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What motor you goin to run?
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Old Jun 14, 2011, 05:41 AM
Chris R
United Kingdom
Joined Dec 2009
713 Posts
Quote:
Originally Posted by latin105fm View Post
Hi all, quick question. I need to get some Lipos and wondering what to put in my Non built Skywalker..... Going to FPV it and use a 60amp ESC. I Wouldn't might having some power to it and obviously length of flight. Will a 5000mAh 4s be too much?

Cheers
4s 5000mah lipo is idea if your using a suitable 4s motor.
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Old Jun 14, 2011, 06:52 AM
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United States, NC, Wake Forest
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Quote:
Originally Posted by Daemon View Post
Making the thrust line more parallel to the long axis of the plane with
a high mounted pusher will make it pitch forward *more* not less. Pitch changes with
power depend on three things.
1. Airspeed and CG location. If you're nose heavy it pitches up with higher airspeed. If
it's truly tail heavy then it pitches forward with increasing airspeed, which is not stable.
2. Thrust line relative to sources of drag. If the thrust line is above the major
source of drag (the wing is the greatest contributor to drag), then rapid increase in thrust
causes it to pitch forward.
3. Thrust line relative to true center of mass of plane. If thrust line is above
center of mass, then rapid increase in thrust causes it to pitch forward.

You can help 2 and 3 by angling the thrust line down toward the source of drag
and/or center of mass, which is why it is angled the way it is. Same for the EZ* and
most other high mounted pushers. The SW is *so* tall though, its center of mass is always
very low relative to the thrust line, so if you have a lot of power, it will always pitch forward when
you go to full throttle quickly. The solution is, ramp up the throttle more gradually
to give the plane time to speed up, and that'll reduce the forward pitching moment
caused by 2 and 3.



That is correct.

ian
Ian,

I noticed (or think I did) that you did not change the angle of the motor when you made your modified mount to run a bigger prop. You just simply raised the mounting point correct? Did that have any affect on what you mention above? I beleive I also read in your proevious comments on this subject you you have little to no pitch in the plane. I suppose this has to do with true proper COG and, well, superior throttle control?

question for you and everyone, I am about to maiden my SW. What should the proper throw limits be on the various control sufaces? Ian I noticed you mentioned + or - 5 degrees on elevator. What about rudder and ailerons? I cannot do differential on ailerrons due to limited channels (i am using a Y cable) so what would be a good mix or aileron to rudder to start with?

Thanks! I have this impending fear that I am gonna toss this plane in the air, it will fly for a minute and come down like a rock becuase I set something wrong!!!

Thanks!
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Old Jun 14, 2011, 08:27 AM
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mustangbrandon don't be too nervous. I felt the same on my maiden. After reading all the threads in all the various forums I got to the point where I felt it's now or never. I got some one to launch the SW horizontally without putting too much effort into the throw. The SW set off and started to pitch up, got it horizontal with a bit of down and then let it climb to a safe height before putting in quite a lot of down trim. Turns were a bit hairy, the ailerons being a bit slow to take effect but nothing frightening. After a few manoeuvres I was happy the plane was controllable and enjoyed the rest of the flight.
Good luck.
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Old Jun 14, 2011, 09:58 AM
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Quote:
Originally Posted by mustangbrandon View Post
Thanks! I have this impending fear that I am gonna toss this plane in the air, it will fly for a minute and come down like a rock becuase I set something wrong!!!
Thanks!
Hi mustangbrandon,
Do and re-do your pre-flight checks and go for it.

I have done 4 flights with my skywalker, LOS before installing the FPV kit.
Here is what I have learnt:

Flight 1 - Did not have enough aileron throw, lost control, got into a spin and ended up in the top of a tree. Snapped tail off just below tail plane . Increased the aileron throw, repaired with gorilla glue and fibre tape.

Flight 2 - <15 seconds, nose in to ground . Conclusion: did not launch with enough power, did not have enough air speed to get control or height. Smashed nose in, repaired with gorilla glue and fibre tape.

Flight 3 & 4 - (today) Re checked everything, CoG ~20mm behind servo wire, good aileron throw. 75% throttle, good fast throw, gained height and enjoyed 15mins of exploring the behaviour and limits.

Landing required faster approach than I am used to with my Hawksky but two successful landings brought a smile to my face.

Hope that helps you skip my first two disasters and go direct to a big

Regards, Mark Leman
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Old Jun 14, 2011, 10:21 AM
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latin105fm's Avatar
London, UK
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Quote:
Originally Posted by rcimports View Post
What motor you goin to run?
Up for a Solid Motor suggestions???? Some some power to push the weight that it will be carrying

Anyone have some good experiences with anything??

Cheers

Dan
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Old Jun 14, 2011, 10:43 AM
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latin105fm's Avatar
London, UK
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Quote:
Originally Posted by latin105fm View Post
Up for a Solid Motor suggestions???? Some some power to push the weight that it will be carrying

Anyone have some good experiences with anything??

Cheers

Dan
PS: I think I might also buy some Nano-Tech Lipos (6000mAh 3s)
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Old Jun 14, 2011, 11:14 AM
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United States, CA, Fountain Valley
Joined Aug 2008
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Quote:
Originally Posted by latin105fm View Post
PS: I think I might also buy some Nano-Tech Lipos (6000mAh 3s)
I'd consider this motor if I am not sure whether I'll be using 3S or 4S:

http://www.innov8tivedesigns.com/pro...2e9864b41738a3

On 3S one can run a 10x5E, 10x7E or even a 11x5.5E if it'll fit on the plane.
On 4S one can run 9x4.5E or 9x6E.

If you haven't bought the LiPos yet, consider buying 4S rather than 3S simply because of then having to only step-down voltages for on-board 12V equipment. A second advantage is less losses due to lower amp-draw at the higher voltage.
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Old Jun 14, 2011, 11:26 AM
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latin105fm's Avatar
London, UK
Joined Jan 2009
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Quote:
Originally Posted by henkvdw View Post
I'd consider this motor if I am not sure whether I'll be using 3S or 4S:

http://www.innov8tivedesigns.com/pro...2e9864b41738a3

On 3S one can run a 10x5E, 10x7E or even a 11x5.5E if it'll fit on the plane.
On 4S one can run 9x4.5E or 9x6E.

If you haven't bought the LiPos yet, consider buying 4S rather than 3S simply because of then having to only step-down voltages for on-board 12V equipment. A second advantage is less losses due to lower amp-draw at the higher voltage.
I bought this a few months ago...

Scorpion 3014
Item Number scp3014 / 23018 / WS3 , Options: Wind(3014-16 (1187Kv))

is it the same one?

Cheers
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Old Jun 14, 2011, 11:29 AM
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Lakewood, Colorado
Joined Aug 2002
28,203 Posts
Quote:
Originally Posted by mustangbrandon View Post
Ian,

I noticed (or think I did) that you did not change the angle of the motor when you made your modified mount to run a bigger prop. You just simply raised the mounting point correct? Did that have any affect on what you mention above?
I can't say what effect it had because I never ran a motor at stock location.
I didn't change the thrust line angle. If I'm low to the ground and mash it to full
throttle, it will pitch down a bit until the airspeed picks up, for the reasons mentioned above.
Quote:
I beleive I also read in your proevious comments on this subject you you have little to no pitch in the plane. I suppose this has to do with true proper COG and, well, superior throttle control?
For normal flying, my SW is almost pitch neutral across its entire throttle range from
gliding to full throttle. It still has a little bit of positive stability so it'll glide level,
hands off, but if I roll onto the throttle smoothly the nose doesn't go up or down.

Quote:
I cannot do differential on ailerrons due to limited channels (i am using a Y cable) so what would be a good mix or aileron to rudder to start with?
Actually you can get some differential and should. Angle your servo arms forward
and lengthen your pushrods to re-center the control surfaces. That'll create mechanical
differential and they'll go up faster/further than they go down.

Quote:
Thanks! I have this impending fear that I am gonna toss this plane in the air, it will fly for a minute and come down like a rock becuase I set something wrong!!!

Thanks!
The SW is pretty much too stable to ever do that unless you have controls reversed or something.

ian
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Old Jun 14, 2011, 11:48 AM
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United Kingdom, Bradford
Joined Jul 2010
92 Posts
Well, thanks for the motor advice guys, just got one of these :-
Turnigy TR 35-36 1450kv Brushless Outrunner
Name: motor.jpg
Views: 142
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Description:

All installed ready to go, going to test it after dinner tonight, will report on the change in thrust from my 2814 830kv.
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Old Jun 14, 2011, 12:41 PM
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Saint Petersburg FL
Joined Jun 2009
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Quote:
Originally Posted by omegamanuk View Post
Well, thanks for the motor advice guys, just got one of these :-
Turnigy TR 35-36 1450kv Brushless Outrunner
Attachment 4080696

All installed ready to go, going to test it after dinner tonight, will report on the change in thrust from my 2814 830kv.
What ESC are you using with the Turnigy TR 35-36 1450kv Brushless Outrunner.

thanks
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Old Jun 14, 2011, 01:13 PM
Whats the wrst that can happn?
AdamChicago's Avatar
Chicago, IL USA
Joined May 2010
2,650 Posts
I used to not, but I do now because I added some extra weight.

Quote:
Originally Posted by Mikey636 View Post
For the guys with flaps, do you hand launch with them down?
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Old Jun 14, 2011, 01:16 PM
Whats the wrst that can happn?
AdamChicago's Avatar
Chicago, IL USA
Joined May 2010
2,650 Posts
Get a Zephyr...they're rockets and very responsive...good for proximity flying.

Quote:
Originally Posted by Vantasstic View Post
I flew my SW near a out cropping I wanted to video. I was reasonably close to the outcropping and felt the SW was a little to much of a floundering slug for close quarters flying and needing quick(er) control response. This is the first time I've flown the SW in a tighter environment. All my other flights have been more long distance 'cruising' flights and/or in open area. I think I'm going to need to add another FPV plane to my hanger. The SW for 'cruise' flights and something a little more nimble for 'responsive' need flights. Looks like I need to pull out my spare EZ* kit and FPV it.
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