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Aug 06, 2009, 06:37 PM
FPV-flier
oxo2's Avatar
Thread OP
Build Log

2m Shadow UAV project


Hi!

I wanted to present you my actual project:
It's a Shadow 200 1:1.7 with 2m wingspan.
Earlier this year my 1.5m shadow hit a phone cable (which was almost invisible in fpv...) and crashed. Because this plane flew very well and had lots of room for equipment, i decided to build a 2m version now.

here's a picture from the original:


Here are the features i've planned to include in my model:

FPV system with audio:
- KX191
- 2.4GHz 100mW Tx
- amplified mic
- modular 270 pan/90 tilt system (wide platform with enough space for a strong flashlight or a second cam)
- EagleTree OSD Pro

Data aquisition/sensors
- ET eLogger V3
- Airspeed sensor
- Altimeter
- GPS
- RPM sensor
- Motor temp sensor
- FMA CPD4 stabilization system (maybe artificial horizon in the OSD later...)

propulsion system:
- 1.4kW turnigy motor
- turnigy k-Force ESC
- 6s 3700mAh LiPo

additional features:
- position- and maybe landing lights
- 3 RC switches for switching lights on/off or igniting smokers or firework
- maybe a servo to drop some cargo...

For all those components i'm going to make a little PCB to avoid tons of wire...

That's a whole lot of features, but first i have to get the plane in the air.
Here's the actual status:







The wing consists of three pieces that can be separated. The fibreglass tubes holding the tail are glued to the centerpiece.
The next step is installing the wires for the servos and lighting. After that i'll cover the wing wit 1mm Balsa.

cheers
Simon
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Aug 06, 2009, 06:38 PM
FPV-flier
oxo2's Avatar
Thread OP
Do you have any suggestions for the covering of the wing?

My first intention was to cover the wing with 1mm balsa sheets and then cover the balsa with 1 layer of 80g/m^2 epoxy and glass.

I'm not sure if the glass is too heavy, or if it's stable enough without the glass covering. I also thought about using parquet coating and glass cloth, to avoid that epoxy stuff, but no idea if that works?
Aug 06, 2009, 07:07 PM
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spyder11's Avatar
awesome! any pics of your old shadow?
Aug 06, 2009, 07:31 PM
Registered User
jsullivan05's Avatar
Couple questions, what are you wanting to accomplish with this new UAV and its size? Are you making it very big for the ability to carry more weight? i.e. another battery/better camera/more stuff in general. Or are you doing it for better thermal riding? or... because big planes are friggin cool? lol

For the cover material, I'd use that shrink wrap plastic cover stuff, i cant think of the name of it for the life of me, but i have a roll sitting right next to my desk lol
Aug 06, 2009, 08:23 PM
Registered User
Hi !

"propulsion system:
- 1.4kW turnigy motor
- turnigy k-Force ESC
- 6s 3700mAh LiPo"

I would suggest to put something VERY solid as covering cause IF you put throttle to max even for 1 second, there will be nothing left on your wings......and then it will be more like a missile..... or a land dart... with a motor.

Why a so powerful motor on a plane you surely want that it says up a long time ? I dont even mention that such a brick will not help your plane to glide much. Motor choice: Odd ( for that airframe) but everything else seems cool to me.

Cheers.

Alain.
Aug 06, 2009, 08:58 PM
Suspended Account
Why only a 3700mah pack, for 75 or so grams more you could get a 5000 mah, on a plane of thats size the added weight should not be a problem
Aug 07, 2009, 02:43 AM
Registered User
I second that!

Go up in battery capacity, go down on motor wattage. It's just useless weight, money, and bottom line loss of flight duration. It's not like this airframe can take advantage of it.

Dimitris
Aug 07, 2009, 04:01 AM
FPV-flier
oxo2's Avatar
Thread OP
Hi!

Thanks for your input.
This is the motor i' already have: TGY Motor

It has similar weight and kv as the axi 4120/18, with which i played around in drivecalc.
I guess my plane will have a weight of 3 to 4 kg, depending of equipment.

With the Axi and a 14x7 prop i get about 4kg static thrust at about 1kW (45A) input power. I think that's not too much, because i want a good climb rate. On the other hand, the motor's max power is not reached with this setup. But with some tests with a 12x12 prop the motor got slightly warm after about 30s of full throttle. According to DC, that's also about 1kW, so i guess, 1.4kW is too much for the motor anyway concerning that i'm flying full throttle from the start up to the desired altitude.

Concerning the battery capacity, you're right. 3.7Ah isn't very much. I've two 3s 2200mAh here, i'll put them in parallel to the 3700's for extended flights. I'm just not sure, how much weight the plane can handle without getting a (too) high landing speed...

Thanks for your input
Simon
Aug 07, 2009, 04:12 AM
FPV-flier
oxo2's Avatar
Thread OP
Quote:
Originally Posted by jsullivan05
Couple questions, what are you wanting to accomplish with this new UAV and its size? Are you making it very big for the ability to carry more weight? i.e. another battery/better camera/more stuff in general. Or are you doing it for better thermal riding? or... because big planes are friggin cool? lol

For the cover material, I'd use that shrink wrap plastic cover stuff, i cant think of the name of it for the life of me, but i have a roll sitting right next to my desk lol
The main goal of the bigger size is having more room for heavier equipment and more stable flight. If the plane handles well then maybe i put in a HD cam, or i'll do some tests with two cameras with different lenses.
Another advantage ist the higher climb and flying speed, unfortunately also a higher landing speed.

Oh, and, yes, bigger planes are friggin cool
Last edited by oxo2; Aug 07, 2009 at 04:18 AM.
Aug 07, 2009, 04:25 AM
FPV-flier
oxo2's Avatar
Thread OP
Quote:
Originally Posted by spyder11
awesome! any pics of your old shadow?
Here you are:









And this video was taken with it:

Test with different lenses
Aug 07, 2009, 05:04 AM
Suspended Account
I am doing the math in my head at 6am so correct me if I'm wrong, but if you're pull 45 amps with that motor, that is 3/4 of an amp a minute. Using a 3700mah pack you will drian it in less then 5 minutes at full throttle. You will be lucky to get over 12 minute flights with this bird and you better land it on the 1st try.
Aug 07, 2009, 06:04 AM
FPV-flier
oxo2's Avatar
Thread OP
Hi Tarro

Yes, you're right. At full throttle it's empty very fast. With my Ez glider i had 20min+ flights just by climbing on 500m and then soaring back to the ground. The shadow is no glider but i hope it will soar quite well, so that i need 1min full throttle to climb and then get a few mins of soaring.

But it looks like i've got to add the two 2200's anyway. It would also make sense concerning the security, as everything will be powered by the main battery (via UBEC's). With those 2x6s in parallel i still got control even if one cell fails.
Aug 07, 2009, 06:14 AM
Suspended Account
Quote:
Originally Posted by oxo2
Hi Tarro

Yes, you're right. At full throttle it's empty very fast. With my Ez glider i had 20min+ flights just by climbing on 500m and then soaring back to the ground. The shadow is no glider but i hope it will soar quite well, so that i need 1min full throttle to climb and then get a few mins of soaring.

But it looks like i've got to add the two 2200's anyway. It would also make sense concerning the security, as everything will be powered by the main battery (via UBEC's). With those 2x6s in parallel i still got control even if one cell fails.
At 3kg to 4kg this is no glider, what will the wing loading be?
Aug 07, 2009, 06:25 AM
FPV-flier
oxo2's Avatar
Thread OP
The wing loading is about 50g/dm^2 with 3kg, 66g/dm^2 with 4
Aug 07, 2009, 08:55 AM
Closed Account
Amazing plane you're building again, i still have the pictures of your original one here in my computer, i saved them because i wanted to copy your plane for myself, lol.

Look forward to seeing how goes.

Yeah, those poor little lipos are not going to stand much of a chance, lol.
And the 12x12 it totally the wrong prop as youve discovered.

Question, what if the largest prop diameter you think you can get on here with ground strike when taking off?

I'll put an idea out for you.
Run the motor on 3S with a large prop, you will have heaps of thrust for vertical climbouts, and be pretty low on the amp draw.

I can give you a dozen examples of what ive done that has worked really well, i fly planes on 12S to 7,000 watts, lol.
But what i enjoy more is running em at half the voltage with very big props, it works really well, even on small motors.

with a 500kv motor, you could try a 18x10 on 3S, see how many amps it draws. will give you 4.5kg thrust, hopefully for less than 40amps.
speed maybe in the 80kph range, not so bad...

Anyways, its just a suggestion, if you have some props like that laying around, do a test with them, see what the numbers show.

If you can run an 18x10, then you can easilly just do 3S and 10,000Mah.
That should let you fly over the border and back, lol.

Anyhows, good luck, i'll be watching how your build goes, its looking good already.

cheers


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