Coyote`s X8

[Coyote]

Ok so after the small cock-up at Bardney I got the X8 back and although the damage seemed minimal, but after the poly-tunnel tape was removed it was a bit more mashed than first thought.

In the event, I lost the Gopro and my Scorpion SII motor and prop.

As always, every flight, particularly every crash instead of replacing I think about why did it happen and what can I do to improve or get rid of the said problem. In this case it was all down to me not plugging in lipo number 2 :) The reason was tiredness and not noticing it was not plugged in with all the connectors in there on tails.

So to combat this I remade the whole thing. Stuck with the good features, got rid of the bad features.

First job was to get rid of the lipo socket tails. The reason why was the only power wires that will then be seen will be the wires from the lipo`s only. That meant surface mounting the sockets. Then I wanted it to be more clean looking, so everything stuck out and looked more obvious if not plugged in.

So I came up with this :



As you can see, the connectors stand out like a turn in a cocktail glass :) The only wires will be the lipo wires - No more mistakes there :)

Next base board done :



I have swapped out the FY31AP and Hornet for the RVOSD Gen 5. |So rewired the board and other components, the reason why was simple enough. The current sensor was that far out it wasn`t even funny, you can not push the limits with duff information so the FY went.

The RVOSD though is super sensitive to vibrations, what I found worked really well on heli`s ( high vibration platform ) was some life preserver foam from the pound shop. Cant remember how much it was now :)



RVOSD in, Telefly OSD ( antenna tracking ) in, PSU for filtering in :)



Various repairs to the body were done, then the lid went on



What I also wanted from the RVOSD was true airspeed. So I have added an air speed sensor to the RVOSD input and a pitot tube. My first location ( not pictured ) was giving me too higher results, prob due to a vacuum from an inlet near where I had it, so I relocated it on the top.



Launcher hook added :



Motor and prop replaced. I went with a Turnigy SK 3542 840Kv with a 12x8 prop. The reason is that others are getting 6 amp cruises, if it can do that it basically doubles my range without any additional weight. Well we will see :)



Last up, the wing connections. At the meet I had a broken wire from the previous landing. Rich came to the rescue but we had to bodge it to get going. Why ? Because although the cables were good they were susceptible to damage and when the wing came away a bit damaged them.

The fix was to make the wires come away easily, beef up the strength of the wires too.



There sorted :) Jst for power, servo for A/V job done :)

I also added carbon vinyl to the bottom of the wings then cut, marked and taped the CoG line for easy balancing

Ding Ding ! Round 2 ! :)

[Coyote]

The Scorpion was my favorite by far, plenty of take-off power decent 10 amp +/- cruise, very good. But not the most economical if your after long range, it still got it 10km and would ave gone 15km probably so for general that`s my fav

Your motor choice should be fine with a 13x7, just watch your launch buddies fingers :)

[skyscraper]

Wow! Very professional. Fascinating read.

The inside of your plane makes the inside of my wing look like a bowl of spaghetti!

regards
Andy

[Miles]

What servos did you use in this?
Cheers,
Miles.

[Coyote]

Hi Miles, they are Spektrum DS821 servo`s in the wings

[Miles]

Cheers.

[Coyote]

After a time the X8 has had that many mods and repairs it was starting to look old and tired. It was in need of a rework for sure.

The goal was to make it much stronger, fit all new FPV gear to it, have less weight, less drag for a faster and more efficient cruise. Also to get rid of any unnecessary contours that can catch air or creat drag, this included the finger holes for hand launching that are no longer used and edges on the top of the body which break the shape up, but only serve to hamper performance.

So at Keith`s we set about the procedure :

The first mission was to strip the bird, all the tape came off, then all wires pulled out. Then I set about cutting the foam to make proper bays for the new layout



Here it the Lawmate 2.4ghz Vtx bay. There is a lot of room in here so that if I decide to go back to Immersion 2.4 then there is plenty o room to fit their new Vtx.

On the underside the previous wiring and glue / filler was removed



On the other wing a bay was cut for the APM 433Mhz telemetry radio.

I used correx to make the lids for the Vtx and Telemetry radio, this is because the correx groves hold the circuit boards nice and tight without the need for tape, but can easily be removed and refitted without on tools or any body damage





So the new wing configuration will look like this :



Next the wings were sanded, channels had depron glued in to save weight over filler and give more strength, then all sanded again.

Next we got some packing paper, ripped it up and started to paper mache the plane :) Yes paper mache it :) :)







Here are the wings covered, they are then sealed with PVA and left to dry out



Once dry and initially sanded we add the first layer of base coat white paint



This is then sanded, painted, sanded again etc etc until its very smooth.

The body has gone through a lot of work.

Here you can see the balsa front hatch has been cut and going to be shaped, this will allow access to the front for any CG weight needed.

I have cut channels then glued in trunking to house the wires for the wings and to give access to connect the plugs / sockets





The balsa hatch now shaped



The lid for the body got that same treatment



The main body once filled sanded, the GoPro bay made out of ply. It was then time to cover it



You can now see the much stronger bay made from ply for the GoPro to fit in, this is now in this picture getting its first base coat white layer





Due too having nearly no spare time Keith cracked on with the covering and sanding painting while I have been at work to keep the project ongoing, big thanks for that bud :)

So the final layer of paints been applied, and the first layer of varnish going on  :

[dogzilla]

what is the point of the paper mâché? to smooth the wing surface?

[Coyote]

It's to give it a rock hard surface that is smooth for less drag. When you paper mache with say a balloon like at school, once the balloon is popped, it's hard but weak to hit. With this though the balloon is replaced with foam bonded to it so the strength is all there, once the paint and the varnish is finished its surface is very hard.

Keith had done it already to his Striker, I was dubious until I had a look at the striker, still light as a feather buta screwdriver wouldn't mark or dent the surface.

[chris-s]

Neat. It's a while since I used that technique on balsa models it adds a bit of weight but I doubt it will be noticeable on that airframe. Make sure you seal it before painting. I moved from brown paper to glassing and have just done my skywalker fuselage, super smooth and only 30grams heavier.

Looking forward to the updates.

Chris

[dogzilla]

So basically standard paper mache with PVA, then you sand and paint it and then you varnish it? Interesting technique seems like it could be pretty strong. Does seem like a bit of weight but the X8 looks like it can take it.

[Coyote]

Yes that's the basic principle, weight increase though was surprising. The naked wing with all tape removed from previous strengthening was only 1.2oz lighter than the finished wings. Add to that the weight of the tape and the increase is negligible really. I thought it would have been more to be honest, I wish I had weighed it before removing the tape as well but never mind

[Coyote]

I didn't really touch on what's changing with it, so I will elaborate.

The RVOSD is being replaced with the APM 2.5 with Arduplane flashed
APM telemetry fitted into one wing
The Gopro 1 is getting replaced with the Gopro 3
MFD antenna tracking via Telefly OSD
Minim OSD
WDR 600 camera
Lawmate 500mW vtx replaces ImmersionRC 500mW
Zippy 5800mah 4s replace Turnigy Nanotech 5000mah 4s
Scorpion SII 3020 1100kv with 10x6 Graupner prop

The idea is to exceed its previous best from 10km ( 10km out 10km back ) to a 20km range

[Jameskibler]

Thats looking awesome now coyote. i see five battery straps.. Are you putting 5 5800mah zippys in there? or is it just to be able to space the batteries out differently?

James

[Dizzy]

Some neat idea's coyote fingers crossed she gives you many happy hours FPV  :D

dizzy :)