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Mick
2011-03-26, 04:08 PM
Just started putting it together so I thought I would document it so others can learn from my mistakes as usual.

The shopping list:

Skywalker 163cm wingspan FPV foamy: http://www.bevrc.com/skywalker-168cm-epo-airplane-version-iilimit-time-offer-p-17.html

Motor: TGY AerodriveXp SK Series 35-36 910Kv / 310w http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7074

ESC: Mystery 40A Brushless Speed Controller (Blue Series) http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9482

9x6 prop and a 5000mAh 4S battery

4x HS-65MG servos. I originally intended to use HXT900 as I had them but decided it was too expensive a plane to trust to cheap servos. I swapped them after taking the pics.

I will use my existing 1.3Ghz video Tx/Rx, OSD Pro combo and Hitec Aurora 9 2.4Ghz radio for now, I am still waiting for Eagle Tree to release the Eagle Link http://www.rcgroups.com/forums/showthread.php?t=1205574 for conversion to long range.

For stabilisation: FY-20A http://www.feiyudz.cn/a/gb2312/product/Flight%20Stabilization%20System/FY-20/2010/0802/3.htmland and AHI http://www.firstpersonview.co.uk/on-screen-displays-osd-gps/s-y-link-eagle-tree-to-fy20a-interface. This is an interim to the new Eagle Tree Guardian http://www.rcgroups.com/forums/showthread.php?t=1399687

You may gather I am an Eagle Tree fan, true but also once you have the core of their system you can add extras very easy as they daisy chain together via the bus. Their strategy works for me.

The build:

I spent a long time reading threads on RCG http://www.rcgroups.com/forums/showthread.php?t=1223595, laying out what would go where and planning everything. I like to do this slowly and I am forever changing my mind what to do. There is never the perfect solution, just lots of different compromises.

Finally got the glue out and started to put it together. Following many tips from the RCG thread, I strengthened each wing with a 300 x 4.5 x 1.4mm carbon strip from between the two main spars out to well beyond the aileron servo. I put these in with medium foam safe CA and then sprayed the kicker, this worked well.

I opened out the channel normally used for the Vtx cable and added a large diameter carbon tube so I can feed cables through this later or change the configuration at any time. I found the tube in my box of junk, for those eagle eyed it is the remains of a carbon tail boom from a TRex 450 that ended its life some time ago, doing the funky chicken.

The glue is drying on the fuselage as I type. I noticed that when I put the sides together using the supplied slow fix glue it was easy to take any twist out of the tail relative to the fuselage by over-twisting then it relaxed to the right place. This would not have been so easy with CA or contact adhesive.

So far so good, hope to have this flying when the weather warms up a bit. The main advantage of the Skywalker over my original EasyStar is the volume of the fuselage, it is huge, so plenty of room for more gadgets. It will also take a much larger battery for longer duration flights.

Lots more fun to be had yet.
Mick
2011-04-02, 07:24 PM
Make a bit more progress today as it was too windy to fly.

Installed the GoPro on the nose.

The 1.3Ghz Vtx is mounted up on top, nearly went for the wing tip but too complicated for now. As it needs 12v I made a voltage step down using 5 1A diodes in series, produces 12.4v on a 4s battery but it gets hot so I may think again. I hate two batteries, bad enough using the one in the GoPro, I would prefer to power that from the main flight battery as well but not sure how, it has a mini-USB for charging but no idea of the voltage or the pin configuration.

Any good ideas for a simple, smooth 12v regulator for the Vtx and another one for the GoPro?

Nice big hole in the side of the fuselage gives access to all the stuff, only a receiver installed so far.

Installed the newly repaired and working FY20A underneath the wing, right on the CofG.

Motor and ESC installed and working well, the ESC hardly gets warm even using the switching BEC

Tested everything and all OK so far, nice clear image with no lines from the ESC. I used a ferrite ring on the ESC lead to the receiver but did not try it without it.

That's all for now folks! Time for a drink......
Andrew Fernie
2011-04-02, 07:47 PM
Mick,
Get a 7812 12V regulator from Access, or if you will be in Beaconsfield give me a call and I will give you one. If you tell me what connectors you need I can make up a little in-line assembly if I have the connectors in my parts bins.

They are three pin packages - input, ground, and output. In principle 1A capacity, but it will also depend on how much power it has to dissipate ((Vin-Vout)*Current) as it a linear regulator.

Andrew
Mick
2011-04-03, 08:13 AM
Hi Andrew,thanks for the idea. The Vtx draws about 1 to 1.5A so it will get hot. Is there a simple switching regulator I could buy?
Andrew Fernie
2011-04-03, 09:53 AM
Mick,

I found this one http://www.dimensionengineering.com/DE-SWADJ3.htm. They also have a 1A version. Note that this is only a step down regulator, so your output must be less than your input. There is no explicit statement on their data sheet as to what you can expect in terms of losses, but you could always give them a call or email.

If you are planning on running a 4S down to 3.4V then your input will be a minimum of 13.6V and my guess is that you will be O.K.

If you were happy with your five diode solution you can always find some higher current parts.

Andrew
Mick
2011-04-03, 10:26 AM
Hi Andrew, I have spent hours on Google searching for something like that, great find, well done. I have ordered two of them. Looks a good site for lots of similar gadgets. Many thanks.
Mick
2011-04-16, 07:06 PM
A bit more progress on the Skywalker as the weather is so bad.

Tested the FY20A stabilisation system - all working well.

Installed the Eagle Tree OSD Pro, eLogger, plus GPS, Airspeed and Altitude sensors, including the Prandtl pitot tube.

Connected it all up and wow video straight away and eventually acquired a GPS fix in the apartment, close to a window. All appears to be OK. Gently blew at the pitot tube and achieved 70kph. He he.

Almost ready to fly but there are some horizontal lines on the video as the throttle is opened, a sign of RF noise coming from the ESC. I am still using the power feed for the receiver and OSD from the SBEC within the ESC via a ferrite ring but this is not smooth enough. Hopefully a delivery from HobbyKing will be here soon including a UBEC which might be smoother. If not, then I need to make or buy a L-C filter for it. I prefer to use a separate UBEC just in case the ESC dies.
zorba
2011-04-16, 10:05 PM
Looking good Mick. I checked their website and by the time you done is well over 200 bucks.

What did you do about the CG?
What the Go-Pro weighs?

Cheers
Mick
2011-04-17, 12:14 PM
The recommended CofG is 30mm behind the servo wire slots. To achieve this even with a GoPro you can still use a 4S 5000mAh battery up front and there is enough room for another under the CofG. This thing is built for endurance. The GoPro is 167g including the case.

Which part are you referring to for $200? I try not to add it up.
zorba
2011-04-17, 01:14 PM
Well they have the plane for 99 then motor I thinck 39, ESC 29, servos (the ones they recommend 29.

So by the end is around 200 still not a bad price.Do I make sence?


cheers
Mick
2011-04-17, 02:38 PM
You are right, it is an excellent price for what you get: a big foam box with big foam wings and bits of carbon. The expensive bit is what you put in it, just like your hexacopters, but that is the fun part.
zorba
2011-04-17, 03:01 PM
:p:D:):crazy2:
Mick
2011-04-21, 07:00 PM
Mick,

I found this one http://www.dimensionengineering.com/DE-SWADJ3.htm. They also have a 1A version. Note that this is only a step down regulator, so your output must be less than your input. There is no explicit statement on their data sheet as to what you can expect in terms of losses, but you could always give them a call or email.

If you are planning on running a 4S down to 3.4V then your input will be a minimum of 13.6V and my guess is that you will be O.K.

If you were happy with your five diode solution you can always find some higher current parts.

Andrew

Andrew,

I have just tested one to feed the Vtx, excellent result with a stable output voltage, runs very cool and no lines on the video, altogether a much better result than using 5 diodes to step the voltage down from a 4S to 12v. I recommend them. Thank you for finding this site.
Andrew Fernie
2011-04-21, 07:21 PM
I am glad it worked out. When is the maiden flight?
Mick
2011-04-21, 07:42 PM
Maybe tomorrow........
Ionel
2011-04-21, 10:48 PM
Maybe mine too, tomorrow.
beto9
2011-04-22, 09:36 AM
Not maybe... tomorrow (meaning... today!)
Mick
2011-04-22, 11:03 AM
Almost done, just securing the hatch and final check of CofG. First flight flutters just starting.
Mick
2011-04-22, 11:11 PM
Did the maiden today and it flew very well, exactly as expected very docile and stable. The FY20A 3D stabilisation was excellent, really helped in gusty conditions. This is the video from the GoPro of the maiden, non-FPV, flight set to some groovy music from Cuba.

YouTube - Skywalker maiden 22 April 2011

I then completed an FPV flight of 22min which consumed 1800mAh out of the 5000mAh battery. The video recording of the transmitted video was terrible, not worth looking at, need to sort that out as the view through the goggles was fine as many people found out. The best part of the flight was testing the autopilot Return to Home function which worked really well.