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My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 1:58 am
by Oops
Long story but here it goes. Just hope that someone will pick something positives out of all this.

After weeks of sitting behind the computer trying to figure out what is needed for an FPV setup I ordered the parts. I already had a phoenix 2 meter and lost another one a few months ago due to sun-strike. I promised myself to reduce the chances of this happening ever again. And this time the wife agreed (read: open chequebook ;-) I’ll supply a list of ingredients later but there is a strong tendency for stuff which Bruce had his fingers on and also following the stunts Alishanmao pulls of at his YouTube.

The Phoenix 2000 is rather tight to put all the components in but this plane has a big wing surface area, streamlined and flaps which are effective. Relatively cheap and some part reflect this.

A few mods I did to the plane to create more space: the wooden bracket in the back which holds the rudder and elevator servos can be inverted. Check that the servo screws are tights and you need to sand a little of the bracket otherwise the two sides are a bit tight. This creates a lot of space to put a 1300mA battery and transmitter components.

The transmitter is the 5.8GHz 500mW. It has a large frontal area with the (exposed) circuit board, forced fan cooling and large heatsink with cooling fins. I disconnected the cooling fan and checked the temperature of the heatsink which took nearly five minutes to get hot to the touch. I also removed the circuit board and extended the wiring, which is fiddly but do-able if you have done some soldering before. The transmitter is at the back behind the wing secured with some cable ties, the circuit board inside and the fan stays at home. Now, the phoenix has a big disadvantage in that the wing is attached by four screws (and the servo cables). Anything mounted in this area takes a few minutes to get to. So I put a switch in to activate the transmitter just before launch and switch it off straight after landing. It works fine but it is an extra item to think of as you will see later.

The stock motor is the 2815/1050Kv (10x5 folding prop) with 30A ESC, both items I had my doubt about after problems with the smaller 1.4 meter Phoenix. Again more later. This is powered by a 2200mA 3S 20C. Further mounted inside are the FY21AP FPV Inertial Attitude Stabilizer and AP117 OSD module. All fiddly to mount in the small space available but even the vibration platform for the FY21 fits in. Make sure that the wiring does not pull the FY21 around.

BEV-KX171 is mounted on the canopy, the pan-tilt camera mount has not yet been mounted.

Despite modifications to different parts all worked fine and the Fatshark glasses showed what they suppose to show and more (optical aberrations). I had to use the full eight channels on the Turnigy 9X (with ER9X and FrSky telemetry DIY kit). As said, it takes a while to find a place for all the parts and still keep the weight and balance in check which is near perfect with this setup.

First flight:
Saturday morning and pretty nervous despite knowing that the plane can handle the load which is just under 1600grams. I had done a previous flight with just the FY21 which is such pleasure to fly and knowing the security of return to launch (RTL) in case of loosing sight.

I launched it full power and after bringing it to a good height activated the RTL and put the FatShark on. Dammit… forgot to switch the video transmitter on. Landing was uneventful despite surrounded by very high pine trees on two sides. Flaps really slow this plane down while still have good controllability.

Second attempt, now with pre-flight check and the FatShark showed what the camera shows. Off the glasses and again launched the plane. At a good height I activated the Auto Circling Mode (ACM) away from the Sun (South West). Put on the glasses and while the plane flew itself, I orientated myself with the new wonders at hand. Now, I have been flying models for some time in a previous life (and anything from hangliders to microlight and bigger) but still the joy of having accomplished something which actually works is overwhelming. 87 meters up, 55km/hr, Amps a bit high at 25A!, throttle back, about 300 meter away from launch. Volts all fine, 8 satellites, etc, etc. Enjoy the view. Colours a bit oversaturated, adjust contrast and brightness. Jiggling the FatShark to get a clearer view of the text in the corners.

So after a few minutes I noticed that the plane was down to 56 meters and still loosing altitude. Odd, because it should have stayed at fixed altitude and I didn’t notice a stalled situation. Increase power… I cannot recall what the Amps were before or after but the plane was still loosing altitude. Switch the ACM off but left the Stabilized mode on and cut the throttle. Down to just over 40 meter and well behind the 30 meter high pine trees. Options. Remove the Shark and run up the dunes past my house and shed, down the dunes to behind the pine trees (287 meters away according to GPS). No way. My first FPV has to be an FPV landing as well.

By now I am sweating in the full Sun (and my poor brains working on overdrive) and this is a second problem with the FatShark: they steam up @#$%. So I had to pull them away slightly to let fresh air flow around.
Down to 27 meters, oops the pine trees are getting close lets bank away and get into final approach. Flaps on, the Stabilizing mode corrects for the sudden nose-up. According to the ripples on the water not far away I am down wind so turn around and now heading into the wind but also increasing the distance to where I am sweating my eyeballs out.

Down to 10 meters and still reasonably good reception (receiver at four meter pole and the 500mW now came to good use). I started to see the little crab holes in the sandy mud. Glasses are getting misty and this time because of reception problems, both video and RC transmitter which start to beep at times. The plane must have been only a meter above ground when I lost video contact but still had RC control (it didn’t beep at that time). Took off the FatShark (not in the Sun, Bruce told me), raced over. Wow, all good with a long skid mark behind the plane indicating a smooth landing. Switched the video transmitter off, heatsink not warm at all. Canopy off and the strong smell of burning electronics hit me. Pulled the battery plug. Is it the ESC? The shrink wrap appears to be ok. Other electronics are also ok. Motor: cannot feel the magnets!

So, for some reason the motor had failed and had even slightly melted the plastic nose. Maybe I had too many amps on while circling and the higher weight of the aircraft? Was it the stock Chinese motor which I didn’t quite trusted before?

Now a lot of lessons learned but still an intact plane. A new motor and ESC is on its way (Hyperion). Don’t know if it is any better but the salesman insisted it was the extra $$ worth. What do you think happened and what motor/ESC would you use? There still should be enough airflow through the fuselage for cooling.

I recovered my wife’s video camera and the next flight I hope to record. Might put it on YouTube. Still a lot more to learn and next flight will be at such place I can land it visually if I need to. But the five odd minutes I had were incredible

Better get back to work to pay for all this.

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 3:33 am
by Sid Sideslip
Wow great post. Happy to hear that you got through that flight OK when the motor died.

The stock motor and esc aren't too good, btw, lots of people have had trouble with them apparently. Also, without cooling holes, plus too much throttle, the motor overheats and melts the nose.

I have the phoenix too and have replaced both esc and motor, I've also built a ply firewall to protect the plastic at the nose and also have ordered a headless spinner to allow good airflow through the motor (via slots in the firewall).

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 4:20 am
by Oops
Good thinking re adding slots to increase cooling. I wait till the motor and bracket has arrived on this Island and drill extra holes. What motor/ESc do you use Sid?

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 4:39 am
by Sid Sideslip
Oops wrote:Good thinking re adding slots to increase cooling. I wait till the motor and bracket has arrived on this Island and drill extra holes. What motor/ESc do you use Sid?


I went overboard and got a Turnigy Plush 60 amp esc http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=2166 and an NTM Prop Drive Series 35-36A 1400Kv / 550W http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14342. 550 watts seems a bit insane but another poster, shotglass, uses a similar set-up and says it works fine...it also flies straight up. :lol:

This is the sort of spinner you need as well, btw. HobbyKing were out of stock, so I paid too much for one elsewhere, damn thing still hasn't shown up either.

Image

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 4:48 am
by bmsweb
Sid Sideslip wrote:The stock motor and esc aren't too good, btw, lots of people have had trouble with them apparently. Also, without cooling holes, plus too much throttle, the motor overheats and melts the nose.


Firstly great post Oops :lol: Great that it had a happy ending! I was expecting smashing ending :lol:

Sid, My son's phoenix was working perfectly . . yes I mean was!! We changed Radios and I was testing and trimming it out. Climb to about 30 ft and I cut the motor and started trimming it out . . all good so far, then power back on again and then nothing! It ended up nosing down and the RX kicked back in again with about 10' off the ground and I just pulled it up and landed safely. The best part was I had a camera onboard at the time and you could hear the ESC beeping and going nuts!

I take your advice on board and will order new ESC (maybe UBEC) and motor too.

BTW: Like the idea of Plywood at the nose!

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 5:15 am
by Sid Sideslip
Lucky escape there bmsweb, old bean.

I have a ubec for my phoenix. I originally didn't bother ordering one, but changed my mind, as I don't like the idea of losing the Tx connection (and plane) if the esc dies. Went for this one at HobbyKing.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6233

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 6:21 am
by bmsweb
Thanks for the link Sid,

I'll upload the video of it when I get a chance and you'll see just how close I got to hitting the deck! I'm still very new to electric models and in the old days when the motor stopped it just meant you ran out of fuel but the radio was still operational :D

We were very lucky to get away with it.

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 6:59 am
by Sid Sideslip
bmsweb wrote:Thanks for the link Sid,

I'll upload the video of it when I get a chance and you'll see just how close I got to hitting the deck! I'm still very new to electric models and in the old days when the motor stopped it just meant you ran out of fuel but the radio was still operational :D

We were very lucky to get away with it.


Yes, you were lucky. I was going to ask you to put up the vid on YouTube; glad you will. :)

That ubec I linked to handles a lot of amps, but I wanted one I could use for much bigger planes later, if I wanted to. Plus, it has pretty lights. ;)

I'm a total noob when it comes to all this electric flying stuff, so I'll probably make some silly purchases early on. I have lots of gear to install, but many of the connectors don't fit each other, for instance. Even my damn charger doesn't have a bullet connector that fits the Turnigy lipos I have ...yet more trips to the shop, or orders to HobbyKing.

Also I keep reading things that I have to learn about or be careful with, lest the sky falls in.

It's like learning algebra, every time you think you understand it, there's a new rule that confuses the hell out of you. :lol:

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Mon Aug 29, 2011 11:24 am
by bmsweb
As promised Sid this is the link to the Video and Thread. I didn't want to highjack this thread :)
viewtopic.php?f=52&t=1158

Re: My first FPV … followed by forced FPV out-landing

PostPosted: Wed Aug 31, 2011 9:19 am
by Oops
Another FPV flight and this time without burning the motor out. Rather windy higher up which resulted in some fast GPS speeds of close to 100km/hr in level flight. Unintended and a bit of a shock to see these things in the goggles. Heading into the breeze showed speeds of less then 10km/hr. I had also the earphones connected but this is rather distracting at this stage. Might become usufull later to "hear" the airspeed while gliding, just like flying hang-gliders.

In my area I have to watch other air traffic which can be a hazard. My spotter notified me that a 172 was approaching while I had no idea what and where till my camera picked it up as a very small spot not far away but still above me.

At times I lost reception, just for a few seconds with a total clear picture before and straight after. I didn't think I had any interference being on an island away from most signal. When the 172 was passing I noticed a few "grey-outs".

The 2D picture makes it more difficult to judge heights and distances so I played it save: landing without goggles (yes, call me chicken ;-) .

Happy to say no steaming up of the lenses this time after putting "Clearlens" on, an anti fog and anti static fluid. Hopefully tomorrow morning I will have another go if there is no wind.