Category Archives: FPV

Spektrum DX6i + EzUHF Receiver + HKPilot32 (aka PixHawk) Channel Mixup

The HKPilot32 (and other PixHawk variants) use a single “muxed” connection from the receiver to the AP.   What I was not ready for was that the channel assignments were all totally mixed up.  The throttle channel is now registering as roll (ie aileron), the roll as pitch (elevator), and the pitch as the throttle!  only the yaw channel remained.

Here’s the stock channels using the latest ArduPilot:Plane firmware (3.1.1):

Roll (Aileron) – Channel 1
Yaw (Rudder) – Channel 4
Pitch (Elevator) – Channel 2
Throttle  – Channel 3

The main issue here is that the channels are fixed on my transmitter (a Spektrum DX6i).  A quick check online shows that the consensus seems to be to change the assignment on the transmitter (oh boy) and not on the AP.  At any rate, this is not viable for me right now.. so I have to implement it on the plane.

The correct parameters to change in either AP Planner or Mission Planner are:  RCMAP_YAW, RCMAP_ROLL, RCMAP_THROTTLE and RCMAP_PITCH.

While these parameters are visible in both applications, for some reason I cant save it with AP Planner and the channels refuse to be reassigned.  The following worked with Mission Planner (v1.3.11):

Roll (Aileron) RCMAP_ROLL – Channel 2
Yaw (Rudder) RCMAP_YAW – Channel 4
Pitch (Elevator) RCMAP_PITCH – Channel 3
Throttle  RCMAP_THROTTLE – Channel 1

Note that this is only for the hardware combination above and may be different in other systems so a little trial and error may be required. Also, while available, changing these settings are not recommended for APM2.5/2.6.

Skywalker 1880 2013/2014 T-Tail Version Mods part 2 of 2

To complete the modifications (see part 1), I felt that not only should the attachments be secure but it should also not require too much effort to remove the elevator.   The plastic plate that will be glued to the elevator has a plastic tab that gets ‘locked’ to the plastic plate on top of the rudder.  To remove the elevator one needs to ‘lift then pull’ that piece of tab.  If you ask me, its too small and requires some unnecessary effort which can damage the damned thing.  Here’s what I mean:

Skywalker Tail Mod
Skywalker Tail Mod

It would have been great if they added more plastic to this tab.  At any rate, the solution is straight forward, get a paperclip or metal cable tie (my preferred choice) and make a small hole near the tip of the tab like so:

Skywalker tail mod
Skywalker tail mod

And here’s the finished mod.. which can be easily accessed using whatever tool is at hand.

Skywalker tail mod
Skywalker tail mod

And We’re Back!.. with the Skywalker 1880 From

My replacement FPV platform is finally here.. after losing the 1900 Skywalker 2014  due to a bad GPS caused by the vibration of  a bad motor (bad bearings) activated by a bad operator (yours truly who ran out of TX juice), I decided to use the same platform but this time with better components (specially the motor!).   The platform remains the 1800 Skywalker 2013 CF tail boom (and wooden pan for the FPV cameras) with the elevator on top of the rudder but this time from

Here’s how it came in:


and the contents:



Here’s the Lowdown:


1) The 1880 wings seems to be thicker and looks like it also has a slightly longer root chord than the 1900 wings.

2) Unlike the 1900 wings it doesn’t come with a CF strip on top for added strength although I don’t think its needed considering its thickness and the fact that it also has a longer dihedral, covering 1/3 of the wing.

3) Because of the large dihedral, this wing doesn’t come with flaps, it only has enough room for the the ailerons.

Tail Section

1) This is the T-tail version, with the elevator attached on top of the rudder.  I think this is a good idea, in my SW 1900 the elevator is attached to the base of the rudder. This has a tendency to get skewed by the tall grass I occasionally land in.

2) The connecting plastic mechanism to snap into and remove the elevator to the rudder seems innovative although looks a little bit flimsy to me.  Looks like I need to do a little mod on this.

All the usual parts seems to be complete.  Will post the components list next.



Skywalker Fly-away $#^$@!

Lost the Skywalker with the Gopro 3 Black and Mobius cameras a-blazing yesterday.    The first indication I was having a problem was the LCD screen on the monitor blacking out.  At this point the plane was not flying very high nor far.. probably not more than 80′ up. The control response were also squishy but I was able to manage to align the plane on the field for a landing but was coming in too high and decided to make another round which was a mistake, at this point even the EzUHF transmitter shut down. This could mean 2 things either the 12v BEC I used for power distribution for the EzUHF transmitter, monitor, DVR and VRx has failed or the LiPO has discharged.  Running back to the field tent to get a spare battery I saw the plane do an RTL and do at least one circle over the launch area.. so far so good.  Couldnt find the spare battery for the transmitter and decided to disconnect the rest of the electronics and just power the ezuhf, at this point I can still the hear the buzzing plane above.. then silence.

Went around surrounding area for a couple of hours but couldn’t find it.

Lessons for this one:

1)  VERIFY, VERIFY that the transmitter battery is at least at 90%.. this is the 3rd flight I made for the day and I remember starting with about 80% (I’m using a Tiger 4S 2800), usually I charge this the night before but not yesterday =(  Checking the battery after showed it was only generating 11.1v.  I completely under-estimated the power drain by the system.
2) Nevertheless, the APM2.6 seems to have gone on a fail safe which dropped to the RTL. I was expecting the plane to loiter above after reaching ‘home’ waiting for a signal (or the battery drains) but this did not happen.  The correct behaviour should have been with long RC signal loss, the APM 2.6 should loiter or RTL and Circle and not make do a hardware fail safe, either that OR the ESC has fail-safe’d, and finally;
3)  At the first sign of power and control issues…land!

G R O A N.

icarusFPV Quad update 3 (disaster!)

The test flight ended in disaster.. it started well enough.. had positive control for about 5 minutes, one thing I noticed with a low kv motor is the slow control response which I think I can get used too anyway. Disaster struck when one of the props shattered mid flight.. I suspect I over screwed the plastic prop and it probably had a crack. The quad fell like a rock from approx 20ft. and landed on its back.  3 of 4 of the motormounts broke off..the motors adapters were damaged though the gps, apm and escs seems to be ok.

Important lesson here is: use CF props on the get go AND if possible use the appropriate prop adapter! yes even prop adapters have CW and CCW shaft threads!

Heres the scene of the disaster..landed where it can do the most damage…on the cement runway =(



and the video:


icarusFPV Quad build update 1

The Hobbyking H4 Copter Multi-Rotor Quadcopter Frame 470mm is well crafted. Carbon fiber motor and body plates with aluminum arms and frame. My only gripe is the motor plates where you screw the motors on.. it would have been perfect if it can readily accommodate the Turnigy Multistar 3508-640Kv 14Pole Multi-Rotor Outrunner.

Heres the build pixs so far:


Main body complete:


with arms:


Finally with motor and escs:


tonight.. power up!

FPV RC Flying Locations in Batan, Batanes in the Philippines

Batanes is a rocky, windy and hilly group of islands.  That being said, despite its small size it boasts of spectacular sea vistas, impeccably kept farm plots separated by hedges,  countless green rolling hills, picturesque lighthouses and yes the surf hitting the rocky shore and cliffs!

Of course one can fly park flyers there but it will not do justice to what batanes offers in terms of land and seascape.  If you want to do FPV and or aerial photography, the best time to do it is in summer ie from March until May where the winds (at least according to the locals) are not that strong.  I visited mid February and was lucky I was able to fly 2 days out of 5 we were there.

Ok some tips:

1)  Best Months to Fly – Compared to other local destinations, Batanes require a bit more from ones vacation budget.  Goods, fuel and supplies reach the Batanes islands via a small ship that travels once a month from Manila to the islands.  Fuel in Batanes is at least 40% more expensive than in Manila.. during the typhoon season when the supply ship cant reach port, the fuel can be 300% more expensive! To get the most bang for the buck, bring provisions (canned goods, noodles etc) and go there during the summer (from March to May).  This should give you the most chance of having calmer and sunnier days for FPV.

2)   Air Traffic – the air traffic in batanes is usually limited to the west side of Basco.  The airport has a “one-way in and one-way out” policy according to one pilot.. meaning, regardless of the wind direction planes always land from the west end of the runway and takeoff westward.    This also means that the entire west side of Basco (up to the airport) should be treated as a no-fly zone for any RC flying of any type.    As of this writing, I understand that due to airport navigational equipment limitations, there are no flights of any type to and from  the Basco airport from 4PM onwards, but you’ll never know. So to be safe..just dont fly on the lower west side of Basco.

3) Transportation – The FPV sites in the main island of Batan (where Basco the capital is) can be easily reached via a rented Van.. it costs about P3,300/day (as of Feb 2014).  If you’re looking for a local tour operator/driver contact  Jhun Gasilao, he knows all of the locations listed here (he drove for us afterall).

4) Bring Enough Cash (and then some) – bring extra cash as there are only 2 banks (PNB and Landbank), though they have ATM’s I understand being offline is a regular thing. And yes, since 21st century (ie internet) telecommunications is flaky (no mobile internet for either Globe or Smart!!@#$@#) certainly no credit card services as well.

Ok enough of that here are the sites:

1)   Vicinity of  Fundacion Pacita (launch point at approx 20°25’48.04″N,121°58’40.62″E)- Pacita is a small bed and breakfast hotel (the best one there!) located south east of  Basco and facing the Pacific Ocean.  The area is littered with small hills with absolutely no flat land anywhere.   The wind from the Pacific is steady enough and predictable but once it hits the cliffs and hills in the area, expect a lot of turbulence and gusts.   Nice views here, you can fly around the hotel, the hills and  the small chapel/church a bit to the west, fly towards the ocean and then head north towards the “Boulder Beach” at the foot of  Mt. Iraya,  this is a 3km stretch of beach where boulders look like pebbles from a distance.

Dont even think about landing on the narrow roads meandering on the ridges as a) the wind buffeting one side will make it almost impossible to do so and b) the sides of the road either has short concrete barriers or barbed wires (or both!).  Of course, this was all in retrospect and I did attempt to land on the road as any proper flyer would attempt to do.. after several landing attempts I had to settle for Plan B, here’s the video:

2) Songsong Iraya Road ( 20°28’9.41″N, 121°58’12.86″E)- this road is located north west of Basco and is opposite of the boulder beach above.  For me this is the perfect spot to do whatever ‘personal best’ FPV’ing anybody would have in mind.  I made 2 flights in this area, a 2.5km range test north-northwest — a personal best — and another high altitude one which reached 800m+ (not really happy with the second one but had to turn back as my new battery was registering 65%  less than 8 minutes into the flight).

Here’s the video of the 2.5km flight:

3) Marlboro Country in Mahatao20°23’36.62″N,121°57’51.29″E)- this is quintessential Batanes. Basically part of the foothills of some mountain, the hills here also face the Pacific.. also windy but the view is just spectacular.   Since this area is relatively high its also easy to go high enough and fly in the clouds (which I apparently did.. though it wasnt too obvious in my FPV monitor at the time).

Fly eastwards towards the big cliffs, then dive down towards the surf (which I didnt =) ), you can also do a flyby of the Mahatao lighthouse about 2km north-northwest of this location.

Due to the bigger area, landing in this location is easier than landing in the area near Pacita.. however, make sure to land (assuming a headwind coming from the Pacific ie east) from the west.  What worked for me was, on the final, I added some throttle and tried to hug a couple of hills behind where I’m at (ie the plane is lower than my location) and landed pitched up on west side of the launch point.

Here’s the vid:

4)  Basco Lighthouse20°27’8.25″N, 121°57’48.67″E)- this one is just at the outskirts, the north-west, of Basco town and near the “Rolling Hills” (too windy those hills).  As this is near people, if you want to fly here make sure to keep the altitude low — remember this is near town and the airport already — and dont venture beyond the lighthouse as there are already houses and small buildings a hundred meters or so below it.   The launch and landing area is adequate, its also on a hillside which is the norm in Batanes.

I’ve also been to three locations in Sabtang island that would be great FPV flying.. although I didnt fly there (we were on tour mode afterall) I certainly would the next time.

As they say in Ivatan.. Sumayap!  Fly!

FPV flying in beautiful Batanes, the Philippines

Batanes has three major islands: Batanes (the main island), Sabtang and Itbayat.  A couple of airlines have daily flights to the capital Basco.   Unlike the rest of the Philippines, the Batanes islands, because of its location, has 4 seasons similar to other northern climes ie Winter, Spring, Summer and Autumn. The only thing it doesnt have is snow!  This means that for most of the year, its a little colder and, on average, windier than the rest of the country.  For FPV flyers it just means more patience (and luck!) is needed for most of the months.  The locals say the winds are calmer from mid-March until May.

Ok here’s the lowdown:

1)  Safety –  Batanes only has 17,000 people spread across several islands. Even in the capital of Basco, rush-hour means seeing a couple of vans going around (mainly shuttling tourists).   The areas I’ve flown in are largely uninhabited and I was told the airport does not accept air traffic from 3pm onwards.  The runway also has a “one-way in, one-way out” — the words of our pilot — policy landing from the west-end and taking off in a west-ward direction regardless of wind direction.  Good info to know if one is flying several hundred meters (or km!) up.

2) Wind – hills and small valleys, can make for an exciting landing.. I soon learned that landing on small roads on ridges on a windy day is a big no-no.   Thats because after hitting the side of a hill, wind speed accelerates as it escapes on top.  It gets worse in the intersection of two hills which forms a funnel-like valley.   The best option is to land on the side of the hill with no wind. Which means, higher throttle on the approach — as you will lose the head wind  since the hill where you will be landing will now acts as a barrier — and then pitch up at the last minute, so you’re basically landing uphill.

Here’s what I took away from this visit:  Hills = Gusts.  Sea Headwind < Land Headwind.

3) Interference –  Virtually none.

4) FPV Locations – the best bet location (for safety, wind and scenery) for long range FPV is the “Songsong Iraya” coastal road.  It’s located in the north-west part of Basco and its the road leading to the garbage disposal facility.  No villages, just some cows and lots of open space to crash in =)

For a little bit of challenge (wind!, some tourists but the best scenery) go to the “Marlboro Country”, this is on the east side of the island (yes facing the Pacific) and the scenery is breathtaking.. you’ll be able to take videos of the farm lands, a defunct (but well kept) light house, the ocean and the surf!  Hill-side landing is the key to an intact plane here.

I saw at least 7 spots thats excellent for FPV in Batanes and Sabtang Islands.. but only flew in 4 of them.  I’ll post the vids of them soon.  In the meantime, here’s the vid of the 2.5km flight from “Songsong” road:




Last saturday was a great day for flying FPV.. I flew several relatively long flights (ie at least 15 minutes anyway), the first flight was at dawn, 6:30AM and I flew more than 1.4km before turning back and chickening out =)  altitude was about 250m.   I noticed the that the APM2.6+minimosd is heating up quite quickly.. positioned in the compartment under the wings it seems like there’s not much ventilation there in the Skywalker.

After lunch, I used a plastic spoon to create an air scoop and glued that to a small hole in the fuselage to ventilate the APM system.. it proved to be very effective, lowering the temperature from 39.2C (while on the ground) to 36.9C (while cruising).

Took a couple of longer flights and was able to get to 560m in altitude and 1.5+km out.

Manila Bay
Manila Bay from 500m+ in cavite
Home Base!
Home Base from 1.5km away
Metro Manila
Metro Manila from 500m in Cavite. Manila Bay on the left, Laguna de Bay on the right.

Skywalker FPV checkout flight

Had a successful checkout flight of the on-board FPV equipment:

1)  2014 1.9m Skywalker (very much already a crash veteran even at a tender age of 2 months)
2) ImmersionRC EzUHF with diversity for the R/C
3) 700TVL sony ccd camera
4) 2w VTX mounted on the tail boom just before the tail assembly
5) APM2.6 (with 2.78b firmware) and minimOSD for the auto-pilot and OSD respectively
6) 80A Hobbywing ESC (previous 60A ESC was damaged after a crash)
7) 4S 5000mah battery

A week before, during a first test, I had an issue with the GPS and experienced TBE’s during loiter and auto modes.. turns out the external GPS was being affected by the APM power supply.. moved the UBlox GPS and APM to another location (in the compartment under the wing)  and the problem just disappeared.

The day before this test, I upgraded to the APM 2.78 firmware which unfortunately had a bug rendering one of the servos params to be uneditable..a big problem for me since my Ailerons needs to be reversed with the auto-pilot is engaged. Fortunately 24 hours after releasing the software, the developers released a patch 2.78b which solved the problem.

The auto mode in particular is pretty good, as there was a 23kph crosswind.  The APM was able to compensate for the wind and made automatic adjustments in the final approach landing the plane a few meters from the target.  Though in the future, when setting waypoints, one has to give allowance for the typical crosswind direction of a known field and set the waypoints several meters opposite the wind direction.