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Old Jul 24, 2012, 10:46 PM
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Canberra, Australia
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Quote:
Originally Posted by subsonic View Post
From your video, it looks like there was a big pitch up response that put the aircraft into a spin. The aircraft was in a tight right turn at about the 3 second mark, and something caused it to pitch up. Was that you? It entered a spin from then on. What did you do to try and recover it? The correct response would be to neutralise the controls, even pushing down if you have to, in order to un stall the wing and fly out. If the aircraft was in a proper developed spin, pulling up elevator might give the appearance that something is broken, or bending, but the real story is that the wing is just stalled and so no amount of up elevator will pull it out. Fairly typical of models like this.

I was flying with a mate of mine a few months ago who was a new pilot at the time. He had one of those cloud sky planes. He managed to get it into a fully developed spin and could not recover it. After it hit the ground, I looked over at his radio. Sure enough, he was still holding full up elevator and no throttle. He now practices spins and can initiate and end them at will. Pattern flyers will practice two and three full turn spins. The idea is to enter and exit on the same line along the strip.
Mate, I've had the Clouds Fly stall many a time but not like this thing does. I can punch the ANX (Clouds Fly) straight up, kill the throttle, tumble around and then fly again. I dont know if you saw my previous video where the SW wasin a dive and I pulled up and pulled up with no response then it just fliped upside down in a split second. The last time I had plenty of height and I was able to recover. Even if i had pushed down elevator, it was too close to the ground to pull out.

I dont think it was a stall, it had plenty of speed and throttle. Too much throttle I think.

Quote:
Originally Posted by subsonic View Post
Further, are you sure it is permanently dead? Sounds like youíve had a few foamies like this before, so I guess you know what is repairable and what isnít. Itís just that Iím always surprised how easy they are to repair and how good they look after.
Yes, in honesty, it is repairable. The wings is unmarked, there's a crack in the boom behind the motor and the nose is in peices. All which could be CA'd back together like a jig saw.

I know some other guys have flash planes but I started this hobby about 2 years ago to get into FPV. I started with the Heli then went to the Bixler and now this is the pride of my fleet. The Heli now flys 3D, the AXN and Falcon wing park fly, I have a FunJet that I built with ridiculous power that I have not yet been game to fly, there have been many Park Jets destroyed in practice for the Fun Jet and the SW has well over $1000 invested from the Ground Station to the plane. For $84, I want it to be the best it can so I'm ordering another.

Here's the ground station recording. It's all staticy because I was flying LOS and hadn't even worried about putting the antenna up. You can here the motor running pretty hard but my Castle ESC log only shows a peak of 25amp and mostly about 20amp. If you can see throuh the static, I had a reasonable amount of speed on and I had hit RTH. It's Dragon OSD which only controls the surfaces when the sticks are centered so I still had control.

REC 003 cut (0 min 11 sec)


Here is the flip from the previous flight.

After examining this flip some more, it seems the flip only happened at high speed. I was gradually pulling up elevator with no effect and then all of a sudden it fliped. Then it was nose down and diving but much slower after the flip and I was able to pull out rather quickly.

HD Skywalker Flip (0 min 36 sec)
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Old Jul 24, 2012, 10:46 PM
An Aussie in Chicago
Joined Apr 2012
1,286 Posts
AXN's seem to be embarrassingly indestructible. I thought I destroyed mine, ordered a new one. Got sick of waiting for HK and decided to rebuild it. It flew better than before, not before new but before I had many crashes, broke the wing a few times, tail off a few times etc. Now its nearly better than new.

Now since I have 2 I'm going with a 600Watt engine and 4S battery and see what it can do.

I'm sure the Skywalker is not as robust, hopefully I will finish my 1900mm version shortly for LR FPV.
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Old Jul 24, 2012, 10:48 PM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,395 Posts
That crash could have been due to a lot of things, but I doubt very much
that it had anything to do with flexy tail or horizontal stab as very
few people have broken the tail in the air.
And the SW doesn't do "flat spins", unless the wing is broken in the air,
or separated from the fuse (due to not using all the rubber bands properly).
How are you using your four rubber bands?
Frankly I've never seen a SW flying in such a messy state.

The SW doesn't like vertical dives as the wing's high lift airfoil generates a strong
forward pitching moment and it may try to pitch forward in a vertical
dive so much that there's just not enough elevator authority to pull out,
but it doesn't look like that's what happened here either.
That might have been problem with previous flip.

Was that SW even FPV piloted? Most folks don't fly that "hard'
while FPV piloting, since you just can't see where you're going
when you yank and bank that much. [edit]I see in
reply a moment ago, that it was LoS. That explains the general
discombobulated starting attitude. FPV piloted, this probably
wouldn't have happened. This plane will do acro (loops, rolls, inverted), but it is
not a 3D plane, and shouldn't be treated as such.

ian
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Old Jul 25, 2012, 01:43 AM
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Lakewood, Colorado
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Quote:
Originally Posted by RolandS888 View Post
There's an important lesson there.
Not sure what you think it is however.
Only a small fraction of OSDs have an artificial horizon and could
have indicated the fact that a steep bank had turned into a steep dive.
RTH wouldn't have helped unless I knew I were in trouble, which I
didn't until I heard the plane hit the ground 100 yards away.
The lesson I learned from it, was make sure to only fly places with
lights visible in all directions which has worked quite well.
I still don't fly with an OSD or RTH at night.

ian
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Old Jul 25, 2012, 02:35 AM
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Canberra, Australia
Joined Oct 2010
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Quote:
Originally Posted by Daemon View Post
Not sure what you think it is however.
Only a small fraction of OSDs have an artificial horizon and could
have indicated the fact that a steep bank had turned into a steep dive.
I'm using DOSD with FY30A. I haven't had much of a chance to activate the FY30A yet. Only once on the first flight. I found it dulled the DOSD control too much with RTH. I have a translator board so the FY30A will provide AHI on the DOSD.

Happy Days.
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Old Jul 25, 2012, 03:09 AM
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Canberra, Australia
Joined Oct 2010
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Quote:
Originally Posted by Daemon View Post
That crash could have been due to a lot of things, but I doubt very much
that it had anything to do with flexy tail or horizontal stab as very
few people have broken the tail in the air.
And the SW doesn't do "flat spins", unless the wing is broken in the air,
or separated from the fuse (due to not using all the rubber bands properly).
How are you using your four rubber bands?
Frankly I've never seen a SW flying in such a messy state.

The SW doesn't like vertical dives as the wing's high lift airfoil generates a strong
forward pitching moment and it may try to pitch forward in a vertical
dive so much that there's just not enough elevator authority to pull out,
but it doesn't look like that's what happened here either.
That might have been problem with previous flip.

Was that SW even FPV piloted? Most folks don't fly that "hard'
while FPV piloting, since you just can't see where you're going
when you yank and bank that much. [edit]I see in
reply a moment ago, that it was LoS. That explains the general
discombobulated starting attitude. FPV piloted, this probably
wouldn't have happened. This plane will do acro (loops, rolls, inverted), but it is
not a 3D plane, and shouldn't be treated as such.

ian
I guessed from your previous posts that youíd be able to help with this.

Quote:
Originally Posted by Daemon View Post
That crash could have been due to a lot of things, but I doubt very much
that it had anything to do with flexy tail or horizontal stab as very
few people have broken the tail in the air.
I suspect that with the SW setup a little tail heavy (15mm behind servo slots) there is more weight on the Horizontal Stabilizer (HS). I think itís flexes at the centre due to minimal contact with the Vertical Stabilizer (VS) which also flexes a bit itself. The end result is one side of the HS lifting and letting more air past and the other side lowering, catching more air against itself and pushing pressure against the VS. The end result is spiralling rather than dropping the tail and lifting the nose.

Quote:
Originally Posted by Daemon View Post
How are you using your four rubber bands?
Frankly I've never seen a SW flying in such a messy state.
My are in the 4 x triangle configuration shown in youtube vids on this thread. 1 with the base of the triangle at the front and the tip of the triangle ending on the left, the next with the tip of the triangle ending on the right. The next 2 with the bases at the bottom and the tips, one left, one right.

Thanks for telling me my SW flies really bad. I didnítí know. LOL.

Quote:
Originally Posted by Daemon View Post
The SW doesn't like vertical dives as the wing's high lift airfoil generates a strong
forward pitching moment and it may try to pitch forward in a vertical
dive so much that there's just not enough elevator authority to pull out,
but it doesn't look like that's what happened here either.
That might have been problem with previous flip.
I donít think thatís what happened either time. There is no pitch forward. It pulls back then flips upside down in a sideways roll. It amazes me how such a long wing is spun like this. I will say it had a fair amount of wobble to the spin.
Quote:
Originally Posted by Daemon View Post
Was that SW even FPV piloted? Most folks don't fly that "hard'
while FPV piloting, since you just can't see where you're going
when you yank and bank that much. [edit]I see in
reply a moment ago, that it was LoS. That explains the general
discombobulated starting attitude. FPV piloted, this probably
wouldn't have happened. This plane will do acro (loops, rolls, inverted), but it is
not a 3D plane, and shouldn't be treated as such.
I wasnít trying to fly acro. I miss judged my flying field to be big enough. It wasnít. I was on the edge of small town with nothing but farmland to one side.

I went to my usual test area but there was an event on there. I had tested RTH there before and know I have plenty of space to fly. I was a bit disappointed that I couldnít fly there as I had loaded a waypoint route of about a 500m square. I in Canberra, Australiaís Capital City and I donít like to fly too far away around here as if something went wrong, Iíd be struggling to get my plane back. The place I flew this time was close by but I donít know anyone in the area. My usual FPV place is 3 hours drive away and my mate who lives there, is in Japan at the moment.

When I couldnít fly my usual test area I should have just gone home but I had a friend with me as a co-pilot and I was as excited to show him as he was to see it.

At no time did I fly it upside down but I did fly pretty fast and in a pretty tight banked circle. Thatís it. I levelled out and pulled up elevator and the next thing it rolled upside down, I used ailerons to roll back right way up and then it nosed down and spiralled into the ground. I could have possibly corrected the spiral had I had enough height but I just want to know why it happened in the first place?

Happy Days
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Old Jul 25, 2012, 04:07 AM
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Canberra, Australia
Joined Oct 2010
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Further to last.

I am unsure if this happened in flight or as a result of the crash but it supports what I thought about the HS lifting.

When I was picking up the pieces, I noticed this little bit of slack in my Dragon Link Antenna wire.
(see pic 1)
I didn't think much of it at the time.
Then I noticed the indentation in the foam from the HS retainer.
(see pics 2 and 3)
The the retainer had only indented the front and not the rear.
(see pic 4)
Then I found the HS had come away from the VS. It was still firm but had obviously lifted at some stage. I had glued this when constructing with some glue left from my Bixler. I didn't glue it for retention strength, just to ensure a perfect fit with the HS level with the main wing. Note: I am applying some pressure for this photo.
(see pic 5)
Then I found moving the HS like this
Caused the slack in the Dragon Link Antenna wire like pic 1. The HS wont move vertically on the air frame near enough to cause the wire slack, it needed to twist heigher on 1 side, the side with the antenna.
(see pic 6)
Note: I am not a gorilla, I'm just a bit hairy.
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Old Jul 25, 2012, 05:37 AM
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asaak's Avatar
Joined Mar 2012
146 Posts
Hi guys!!

when you buy the skywalker I assume it comes with the canopy that looks alike real one but what I want to ask is where do you get the "flat" canopy special to mount all the fpv gear.

The canopy I am talking about is like the one on the image. Does this also come with the plane?






thanks!
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Old Jul 25, 2012, 05:44 AM
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South Africa
Joined Oct 2005
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Those came with the older SW's, I like them more as well,

"(see pic 6)
Note: I am not a gorilla, I'm just a bit hairy. "

ROFL, funny!
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Old Jul 25, 2012, 08:13 AM
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Quebec, Canada
Joined Sep 2006
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Quote:
Originally Posted by Daemon View Post
Not sure what you think it is however.
Only a small fraction of OSDs have an artificial horizon and could
have indicated the fact that a steep bank had turned into a steep dive.
RTH wouldn't have helped unless I knew I were in trouble, which I
didn't until I heard the plane hit the ground 100 yards away.
The lesson I learned from it, was make sure to only fly places with
lights visible in all directions which has worked quite well.
I still don't fly with an OSD or RTH at night.

ian
OSD would have indicated your loss of altitude. Now that I have it, I think it is a valuable tool, and a good safety (certainly not an insurrance that your plane will be back home everytime though). Would certainly help with orientation in a dark environment with no lights or if lost over unknown terrain. I still think it is not necessary, nor is an OSD, but it is a fun tool to have if you want to play with it.

Taking time to install FPV components correctly and good flight preparation are still the best insurance that you will bring back your plane whatever the equipement in it.
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Old Jul 25, 2012, 12:43 PM
Keep Calm, and Carry On...
seearestacey's Avatar
United States, UT
Joined Feb 2012
398 Posts
Ian, what is the MTOW for the 1680mm wing and the 1900mm? 2500g (4.96lbs for the 1680?)
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Old Jul 25, 2012, 01:29 PM
Whats the wrst that can happn?
AdamChicago's Avatar
Chicago, IL USA
Joined May 2010
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Regarding the recent mis-haps...here's my two cents:

- AHI and especially OSD are huge helps with night flying. It is easy to get disoriented with where you are and a bit with attitude too. Many times at night and even sometimes during the day in a new area I relied on the ETOSD "RADAR" to guide me home. The AHI is a huge help too and works with RTH to ensure a stable flight back home.

- Stabilizing the main and tail is a good idea if you're going to be hard on your SW or are heavy and fast...here's what I've done that has successfully and fully strengthened the SW:
Main wing:
- 1-2 wooden spars across the top full length of each main wing half (use a solder iron to melt out the channels)
- At least two full wing length strips of fiber tape across the bottom of each main half

Tail:
- vertical CF tube down the full length of the vertical stab and into a drilled hole in the boom CF tube...epoxy the connection outside and in the tube as well (this is important because otherwise with use the connection will stretch and become less effective)
- horizontal CF tube from front to back across top of the vertical stab to keep the back of it from pitching backward and forward (you'll have to put it on either the left or right side as there's no room down the center.
- thick and short CF tub underneath and tight up against the bottom of the wooden screw-down plate...to keep the plate from tilting side to side and for extra lateral stability at the top of the vertical stab
- flat wooden spar across top of horizontal stab (1.5in x approx 6in)
- two short (approx 1/2in aluminum spacers epoxied to the bottom of the horizontal stab up against the bottom of the wooden spar that goes across the top and aligned with the screws (ie screws go down through the center of the spacers) This allows for a rock solid connection to the vertical stab wooden screw plate when tightening down the horizontal stab.

Tail/Boom:
- two CF tapes (1/4in) vertically placed to the left and right of center running the full boom length to keep the boom from twisting...this is necessary because as you fully stabilize the tail all of the tension occurs in a twisting of the boom.

It's a lot but it's worth it. Of course there's a lot of added weight but who cares if your running a decent motor
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Last edited by AdamChicago; Jul 25, 2012 at 01:34 PM.
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Old Jul 25, 2012, 02:11 PM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
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Quote:
Originally Posted by joel0407 View Post
I suspect that with the SW setup a little tail heavy (15mm behind servo slots) there is more weight on the Horizontal Stabilizer (HS). I think itís flexes at the centre due to minimal contact with the Vertical Stabilizer (VS) which also flexes a bit itself. The end result is one side of the HS lifting and letting more air past and the other side lowering, catching more air against itself and pushing pressure against the VS. The end result is spiralling rather than dropping the tail and lifting the nose.
Sorry, that's not at all how it works. First of all, 15mm behind servo
wire slots is actually still nose heavy. On a conventional aircraft balanced for
stability, the CG is always in front of the center of lift of the wing. This means
weight ahead of the center of lift is pulling the nose down (which I'll
call "nose weight" even though it has little to do with the nose, while
the horizontal stab has to generate downforce (negative lift) to to push
the tail down to offset the nose weight. A nose heavy plane requires
more downforce be generated by the horizontal stab to balance it.
A true tail heavy plane has the CG moved back behind the center of lift, and
it would require the horizontal stab to generate positive lift to hold itself up.
True tail heavy condition is severely unstable because the plane will
pitch down as it speeds up, and pitch up as it slows down which is
negative stability.
The stock CG location at the wiring slots is severely nose heavy.
15mm behind servo wire slots is still nose heavy. Getting
back around 25-35mm behind servo wire slots is closer to optimal.
At that point, CG is very close to center of lift, and the horizontal stab has
to generate *very little* downforce. In other words, it works less hard,
and is less prone to flexing during normal flight.

However. As I mentioned, in addition to the balance of nose weight
and downforce, all non-symetrical airfoils have some forward
pitching moment. As they generate lift, they're trying to pitch forward.
This forward pitching moment has the same effect as nose weight
and thus must be balanced with downforce from the horizontal stab.
But the magnitude of the pitching moment changes with airspeed
so you can move the CG back to optimal, as long as you keep your
airspeed in check. If you overpower the plane, or put it into a vertical
dive, the forward pitching moment will be so strong it overwhelms
the elevator (bends the foam surface itself) and you may not be
able to pull out, until you slow down. If in a vertical dive, pushing out
inverted may be the only way to recover. Best just to not get it
into that condition.

Quote:
My are in the 4 x triangle configuration shown in youtube vids on this thread. 1 with the base of the triangle at the front and the tip of the triangle ending on the left, the next with the tip of the triangle ending on the right. The next 2 with the bases at the bottom and the tips, one left, one right.
That should be sufficient.

Quote:
Thanks for telling me my SW flies really bad. I didnítí know. LOL.
That's not what I was saying actually. It's very hard to *make* a SW fly
badly. It generally flies itself, just fine.

Quote:
I donít think thatís what happened either time. There is no pitch forward. It pulls back then flips upside down in a sideways roll. It amazes me how such a long wing is spun like this. I will say it had a fair amount of wobble to the spin.
What you describe, sounds like a flick (complete aerodynamic
departure of the horizontal stab, which leads to sudden increase in
angle of attack of main wing, and tip stall to spin), but my SW has *never*
done that and I fly it very hard. How much elevator throw do you have?
It would take a massive amount to induce a stall in the stab, but it's
possible. As you move the CG back, you must reduce the elevator throws.

Quote:
At no time did I fly it upside down but I did fly pretty fast and in a pretty tight banked circle. Thatís it. I levelled out and pulled up elevator and the next thing it rolled upside down,
Again, sounds like a flick. I'm guessing you've got too much elevator throw.

ian
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Old Jul 25, 2012, 02:20 PM
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Lakewood, Colorado
Joined Aug 2002
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Quote:
Originally Posted by carguy1994ca View Post
OSD would have indicated your loss of altitude.
GPS based altitude is unreliable (vertical error is about 4x horizontal error)
and I've found it to be very slow to respond to sudden changes. I was only
flying about 100 feet up, so it'd be hitting the ground about the time
the OSD started to indicate a large altitude drop. I have an OSD on
my X8, and see this lag all the time. I've done a fast vertical climb
and then waited 4-5 seconds for it to *start* to indicate a 300-400 foot
elevation gain.

For whatever it's worth, this is what I was doing flying in the dark
in rural Kansas.
FPV - Fireworks at LEG Fest (4 min 2 sec)

Everything was perfectly fine as long as the fireworks were going, but then
their torch went out. All downhill from there (not shown in vid).
All I needed to stay oriented were a few lights on the horizion, but
they just weren't there for most of the circuit.

ian
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Old Jul 25, 2012, 02:23 PM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
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Quote:
Originally Posted by seearestacey View Post
Ian, what is the MTOW for the 1680mm wing and the 1900mm? 2500g (4.96lbs for the 1680?)
No idea. I don't load my SW up like some. Many people have flown
with 10Ah worth of battery, and some have probably done
quite a bit more than that. Some folks also build very heavy. The main limitation
with a heavily loaded SW is not the flying, but simply launching it fast enough
to get flying.

ian
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