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Old Jun 13, 2011, 01:52 PM
KJ6BFN
henkvdw's Avatar
United States, CA, Fountain Valley
Joined Aug 2008
732 Posts
Quote:
Originally Posted by mustangbrandon View Post
henk,

I'm running a 9x6 on 3s to start. I have a 5000mah batt already... I'm not running heavy to start besides the battery. Have eagle tree components inside and a 900mhz transmitter on the boom. Once I get comfortable with the plane and maybe add a gopro i would step up.

Unless somone sees somthing wrong with this combo...
On 3S and a 9x6E prop, 1020 kV may be on the low side.
The plane will fly but you can get more thrust out of this motor with a bigger prop.
Do some static tests with a 10x7 and a 11x5.5 to determine the amp-draw.
Use the biggest prop you can fit on the plane that does not over-amp the motor at WOT.
This motor should be up to the task of moving all your equipment.
To do so, you will have to get the best matched prop on there.
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Old Jun 13, 2011, 03:29 PM
AMA #535918
USA, NV, Las Vegas
Joined Apr 2006
321 Posts
component placement

I'd like to get some component placement suggestions.

I'm going to put a camera at the nose of the SW and put the motor where it belongs. I want to get good separation between rx's and rf noisy parts. My first thoughts are to put the Thomas Sherrer lr rx on the boom and put the antennas as far back as they will reach. This will put the video tx in the cockpit area with the vee antenna taped to the fuselage side.

An alternative would be to place the v tx on the boom with the vee antenna on the vertical stabilizer. That would place the tlrs rx in the fuse with its antennas poking out just behind the fuse hatches. The tlrs rx would be fairly close to the electronic speed controller.

And speaking of esc's, I have a 60 amp Exceed Volcano Opto hooked to a Scorpion 3014-1220. The top most compartment just in front of the motor would be a nice spot for it. But I'm worried about heat buildup. Keep in mind that I'll be launching when its 100-110 degrees F at times.

The Dragon OSD and 8-15amp bec will be in the fuse. Where should I mount everything else?

TIA.
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Last edited by vegasbs; Jun 13, 2011 at 03:33 PM. Reason: grammer
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Old Jun 13, 2011, 04:05 PM
UAV Pilot
UndCon's Avatar
sweden
Joined May 2007
1,005 Posts
Quote:
Originally Posted by vegasbs View Post
I'd like to get some component placement suggestions.

I'm going to put a camera at the nose of the SW and put the motor where it belongs. I want to get good separation between rx's and rf noisy parts. My first thoughts are to put the Thomas Sherrer lr rx on the boom and put the antennas as far back as they will reach. This will put the video tx in the cockpit area with the vee antenna taped to the fuselage side.

An alternative would be to place the v tx on the boom with the vee antenna on the vertical stabilizer. That would place the tlrs rx in the fuse with its antennas poking out just behind the fuse hatches. The tlrs rx would be fairly close to the electronic speed controller.

And speaking of esc's, I have a 60 amp Exceed Volcano Opto hooked to a Scorpion 3014-1220. The top most compartment just in front of the motor would be a nice spot for it. But I'm worried about heat buildup. Keep in mind that I'll be launching when its 100-110 degrees F at times.

The Dragon OSD and 8-15amp bec will be in the fuse. Where should I mount everything else?

TIA.

Take a look at my site for various Skywalker mods
www.undcon.com

I made a duct to let cool air flow over the ESC in the upper compartment.
GoPro camera is in front
FPV camera on top
Video TX on flat spot behind prop
Video antenna on stabilizer
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Old Jun 13, 2011, 05:16 PM
Registered User
Canada, BC, North Vancouver
Joined Apr 2011
136 Posts
Having a minor issue with my Skywalker. I just flew it for the first time yesterday and it flies amazing! Launches really easy, climbs really well and glides great.

The only problem I have is that if I give it full throttle, the nose dives quite aggressively. So much that I almost crashed it the first time I went full throttle. Is this normal? Anything I can do to counter it?

I have the CG set at about 25mm behind servo wires.

I'm using a Scorpion 3014, 830 kV motor with a 4s LiPo and a 9x6 prop.

It almost feels too powerful as I could barely hold on to it when I went full throttle while hand launching it.
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Old Jun 13, 2011, 05:34 PM
Chris R
United Kingdom
Joined Dec 2009
713 Posts
Launch with no power or with 1/3 throttle only!

30mm behind servo wires is best.
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Old Jun 13, 2011, 07:12 PM
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United States, AK, Anchorage
Joined Dec 2010
152 Posts
For the guys with flaps, do you hand launch with them down?
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Old Jun 13, 2011, 08:06 PM
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Joined Aug 2010
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Quote:
Originally Posted by JLager View Post
Having a minor issue with my Skywalker. I just flew it for the first time yesterday and it flies amazing! Launches really easy, climbs really well and glides great.

The only problem I have is that if I give it full throttle, the nose dives quite aggressively. So much that I almost crashed it the first time I went full throttle. Is this normal? Anything I can do to counter it?

I have the CG set at about 25mm behind servo wires.

I'm using a Scorpion 3014, 830 kV motor with a 4s LiPo and a 9x6 prop.

It almost feels too powerful as I could barely hold on to it when I went full throttle while hand launching it.
I suspect you have the classic x configuration aluminum mounting plate for your engine. The way the fuselage is molded has the thrust axis at a positive angle relative to the longitudinal axis. This naturally causes the nose to be pushed down at high power settings. I would put small washers on the top two engine attachment bolts to change the thrust axis to be more parallel to the longitudinal axis. ( nose to tail axis ) This will prevent the thrust from forcing your nose down at high power settings. Cheers.
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Old Jun 13, 2011, 08:23 PM
Fly Chitty Chitty Bang Bang!
EarthOrbiter's Avatar
Central California USA
Joined Feb 2011
379 Posts
Quote:
Originally Posted by Mikey636 View Post
For the guys with flaps, do you hand launch with them down?
It depends on the plane you are using.
If your engine is down on a real plane you are commited to the glide slope upon landing. Possibly takeoffs will uplift faster. With these RC planes they fly different and are fast in response. You have to be quick.
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Old Jun 13, 2011, 09:10 PM
'FPV'er...not a "LOS'er
Vantasstic's Avatar
Las Vegas, NV
Joined Sep 2003
18,243 Posts
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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Old Jun 13, 2011, 09:51 PM
FPV junkie
m_beeson's Avatar
United States, UT
Joined Jan 2011
3,379 Posts
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.
My favorite plane I ever owned was the chipmunk. That was a great plane...

I would like to FPV a chipmunk for the same reasons...


Mike
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Old Jun 13, 2011, 09:56 PM
Gravity is patient............
Joined Mar 2006
1,910 Posts
Quote:
Originally Posted by Cir2kuk View Post
Launch with no power or with 1/3 throttle only!

30mm behind servo wires is best.
No power? I don't know about your SW, but mine weighs a TON with all the mods and fpv gear. It is not taking off without power unless you've got a big league pitcher tossing it.....
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Old Jun 13, 2011, 10:40 PM
Registered User
Canada, BC, North Vancouver
Joined Apr 2011
136 Posts
Quote:
Originally Posted by thekubiaks View Post
I suspect you have the classic x configuration aluminum mounting plate for your engine. The way the fuselage is molded has the thrust axis at a positive angle relative to the longitudinal axis. This naturally causes the nose to be pushed down at high power settings. I would put small washers on the top two engine attachment bolts to change the thrust axis to be more parallel to the longitudinal axis. ( nose to tail axis ) This will prevent the thrust from forcing your nose down at high power settings. Cheers.
Isn't this intentional though for this plane? I never saw it mentioned in this thread so it doesn't seem like something everyone has to do?
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Old Jun 13, 2011, 11:57 PM
Fast and low...
aa78's Avatar
Joined Apr 2009
837 Posts
I moved the Vtx to the flat spot on the boom behind the motor. Since the ESC is placed near that spot, there was interference from the ESC in some portions of the throttle range.

20110612 - Skywalker EPO FPV Flight (6 min 30 sec)


There was minimal static compared to the last two Vtx positions (canopy and side of fuselage).

There is still a pronounced yaw to the left which was corrected with trim, for this flight. I might need to have a look at the motor's mount to see if it is seated properly.

The SW was flown for 28+ minutes which was squeezed into this six and a half minute clip.

Enjoy!

Skywalker FPV build log
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Last edited by aa78; Jun 14, 2011 at 03:18 AM.
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Old Jun 14, 2011, 01:17 AM
UAV Pilot
UndCon's Avatar
sweden
Joined May 2007
1,005 Posts
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.
I have something similar in mind

I use my Quad(multiwii) for tight spaces and aerial photos but I need to buy the FPV gear for this as well so its partially grounded.

The Skywalker is great for open areas - surveillance-stylee

I have been thinking of a small flying wing for FPV as well for fun flying
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Old Jun 14, 2011, 02:09 AM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,488 Posts
Quote:
Originally Posted by thekubiaks View Post
I suspect you have the classic x configuration aluminum mounting plate for your engine. The way the fuselage is molded has the thrust axis at a positive angle relative to the longitudinal axis. This naturally causes the nose to be pushed down at high power settings. I would put small washers on the top two engine attachment bolts to change the thrust axis to be more parallel to the longitudinal axis. ( nose to tail axis ) This will prevent the thrust from forcing your nose down at high power settings. Cheers.
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.

Quote:
Originally Posted by JLager View Post
Isn't this intentional though for this plane?
That is correct.

ian
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