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Apr 06, 2015, 01:46 AM
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schumixmd's Avatar
I have the crash filmed from 5 different cameras, but I am not very pleased to upload it for the moment because looks like a total fail.
If I will have success the next time, I will include the crash in the video for sure.
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Apr 06, 2015, 03:28 AM
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Arxangel's Avatar
Quote:
Originally Posted by schumixmd
Yeah, of course, anyway I planned to write a review...

The CG of the plane was exactly on the front spar, which is 75mm from the leading edge. The recommended CG is 75-80mm. What I didn't checked and I feel stupid for that, is the Take off weight, but I didn't have nothing extra, the components installed:
1. MFD AP + current sensor in the rear compartment
2. 3000mAh 3S battery in the front compartment.
3. A PZ0420 camera in the nose gimbal
4. DL Receiver in the nose, in the place it is supposed to be installed vTx.
5. A mobius camera looking backward on the center of the wing.
6. A RunCamHD under the right wing at the same distance of the servo.
7. Lawmate 800mw vTx on the left wing sticked with Packing tape. a little bit close to the fuselage than RunCam on the opposite wing.

the plane still seemed a bit unbalanced on the longitudinal axis, banking to the left.

First throw:
I was worried not to let my fingers fly with the plane, and decided to have the motor spinning at 10%, and after the plane is in the air, to hit full throttle.
After lunch, the plane didn't glide at all - left wing stalled and plane nose dived into the planet. When I hit full throttle it was too late.
The launch point was 1-2m higher that the impact point.
Camera lens ate some soil. Of course the gimbal were pushed inside, but only the servo arm broken. And a tail servo was stuck. RunCamHD flew 1 meter away.

in about 15 minutes, the servo was repaired with the gimbal I didn't play at all. let it there only for the weight. Anyway I didn't had any plans for fpv and the camera position was not critical. RunCam was not mounted back, so the left wing was even much heavier this time.

Second throw:
I preferred to launch it from the ground level this time, not from the small hill.
I also decided to engage LAUNCH mode even the AP was not tuned with this plane, but at least it would hold my launch angle first seconds of the flight.
I have analyzed once again probability to chop the fingers and found that it will be achievable to launch it with full throttle already.

Launch - plane climbed 1 m, left wing stalled, nose diving into the plane the second time. In the dive I managed to close the throttle, but anyway - gimbal plastic in the front got some more damages as it is not very flexible and is breaking/cracking easily with the tension.
The rest is intact - except the fact that upon impact the windows are flying away.

Conclusion: The plane don't glide so much as for example Skywalker Naja, that I was throwing without throttle and it glides forward.
The longitudinal unbalancing played a very big role and i'll have to pay attention on this next time, however as I said before, with Naja I didn't have such experience, while having the same configuration of the components.
Hm... very curious results! In the promotional clips the guys didn't have much problem with launching the plane!

This reinforces even further my determination to put a hook on it and bungee launch it! Not taking any more chances with hand launches, when the bungee hasn't failed me once so far!
Apr 06, 2015, 04:01 AM
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schumixmd's Avatar
Quote:
Originally Posted by Arxangel
Hm... very curious results! In the promotional clips the guys didn't have much problem with launching the plane!

This reinforces even further my determination to put a hook on it and bungee launch it! Not taking any more chances with hand launches, when the bungee hasn't failed me once so far!
yeah! that's for sure!
I do agree I did few mistakes this time, but I was so confident...
I had no chance to go 4S, because I don't fly 4s at all, I just don't want, but on 3S with 12x8 prop blades the power measured was barely 130watts. Not much at all...

and another one, is to have someone to throw it for me... doing all alone it seems pretty hard. I will consider bungee lunch for this season for sure.
Apr 06, 2015, 11:15 AM
Registered User
schumixmd's Avatar
Just weighted the plane - 1734 grams - 134 grams heavier than advertised. still used lighter components - because they recommend 4s battery, 3536 motor and 40-60 amps esc.
Apr 06, 2015, 11:18 AM
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Hmerly's Avatar
Thats unfortunate to hear. Just from looking at the plane I'd be afraid to throw it powered up. The prop looks so close to where your hand grips the fuselage.

You may just need 4s power or a different motor/esc combo.

Doesn't look too good though, and I hear X-UAV is already doing some redesigns.
Latest blog entry: My fixed wings
Apr 06, 2015, 12:21 PM
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schumixmd's Avatar
yeah, I am thinking of ordering another motor of higer kv. I had 1000kv motor, and I think I will double the kv's

In last couple of days I've sent a lot of feedback to x-uav. mostly the bad things... hopefully they will adopt at least few of them.
Apr 06, 2015, 04:39 PM
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schumixmd's Avatar
I've published my story guys. I found it better to have it in a separate thread in my blog rather than here.

https://www.rcgroups.com/forums/show....php?t=2386587
Apr 07, 2015, 11:23 AM
Registered User
Hmmmm, fully loaded for a maiden and test/review, thought it might have made more sense to keep things simple and add components afterwards
Apr 07, 2015, 11:28 AM
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schumixmd's Avatar
Quote:
Originally Posted by Dogdude
Hmmmm, fully loaded for a maiden and test/review, thought it might have made more sense to keep things simple and add components afterwards
You're right about that, but as I said, I was, and still am fully confident in the equipment I have installed, except the power plant which provided only 130 watts.

If one would consider this plane for 3s setup like I did, then one should go with at least 1800kv motor.
Apr 07, 2015, 12:31 PM
Registered User
Yes, my 1.4m Skysurfer has 200 Watts on 3S
I think I may have remarked on the flight videos of this that it appeared to be "tip stally", it certainly looks like it may be prone to stalling
Apr 09, 2015, 09:13 AM
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schumixmd's Avatar
Quote:
Originally Posted by Dogdude
Yes, my 1.4m Skysurfer has 200 Watts on 3S
I think I may have remarked on the flight videos of this that it appeared to be "tip stally", it certainly looks like it may be prone to stalling
well, regarding the tip stalling I can't say yet it is definitely true!

Because of the vTx on left wing the plane was unbalanced on longitudinal axis, and on top of that adding the torque that rolled it even more on the left, I still consider it shouldn't be considered as "tip stally", and more testing should be performed.

Will see how fast I can have proper setup.
Apr 12, 2015, 08:54 AM
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schumixmd's Avatar
The retry of the maiden went smoother... working on video now.



Apr 12, 2015, 02:25 PM
Registered User
Pictures look sweet (you git, I may have to buy one now)

Come on, hurry up with the video
Apr 12, 2015, 02:48 PM
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schumixmd's Avatar
I am not sure you'll like the video .. but it's rendering already
Apr 12, 2015, 02:58 PM
Registered User
How noisy is the gear train on the prop drive?

Your right about the motor kv. The prop will spin half as fast as it would normally without the gear reduction. Either significantly increase the size of prop, or increase motor kv. That plane is around 3-4lbs. Personally 350w would be my minimum I'd try and take off with. And roll balance is more significant than most give it credit for. Especially on a tip stall prone plane.