On the weekend I did a 425km flight with my Vigilant C1.

Setting a new distance record is something I’ve been slowly working towards ever since flying 301km with the Cyclops EPO plane in 2014 

John Smith and Gene Robinson of RP Flight Systems supported me by providing the Vigilant C1 airframe. It has a 3m high aspect wing and loads fuselage space making it ideal for long endurance missions.

In terms of flight testing the biggest performance gain was from tuning the powertrain setup. I tested two options, a 4S battery vs a 6S battery with the stock 300kVa motor. The 6S with stock motor won hands down with a performance difference of around 25%.

I also tested half a dozen different propellers, a couple of APM parameter settings, three different flying patterns and different battery payload capacities.

I tested each parameter by flying repeated circuits of an octagonal test lap and analysing the telemetry log files to work out the power consumption. I could calculate the watts used and the distance covered to work out the best settings. I could extrapolate those figures to see how far I could fly if I used the full battery load.

One dilemma I faced was concerning the flaps. With such an efficient airframe heavily loaded I wanted flaps to control the airspeed and glideslope for landing. But I didn’t want to power the flap servos and carry the weight for the whole flight when I only needed them for 30 seconds at the very start and end of the flight. In testing I gradually reduced the flaps each landing and was relieved that I could land easily with a long low approach. I did however have trouble taking off. I used a bungee that dragged the plane along the ground. Even though I achieve plenty of speed, the fact it was on the ground meant I couldn’t rotate to pitch up. With flaps I had enough lift to take off every time but without them I couldn’t.  It took three attempts without flaps the first time to get airborne and even then it only happened because I hit a bump that bounced me up off the ground. I decided to remove the flap servos and glued the flaps in place and I made a ramp out of some plywood sheets and used that for the first time for the record attempt. 

With the 6S setup I used a HobbyKing power module and the figures it gave in testing seemed too good to be true. I calibrated it against the amount of energy the charger put back in and that showed the power module had been underreporting the current used by about 25%.

I watched the weather and picked the best day I could have hoped for. It was very calm for the first half of the flight with only a light wind later in the day. I flew a large loiter circle (guided mode) with a 600m radius giving almost 2km per lap.

I tracked distance covered vs battery voltage and vs battery percentage remaining and found gave very consistent results that sat just above the 400km projection line all day.

I trusted the voltage reading more than the battery percentage remaining. I knew the Li Ion batteries would be 95% depleted when they reached 3V per cell so I planned to terminate the flight at that point.

All in all it was a big day, 425km of flying taking 7 hours, 48 minutes.

What I’m most excited about is the possibilities this milestone opens up. With an airframe like this the range limitations for tasks such as pipeline monitoring, mapping and search and rescue have just been moved to another dimension altogether.

Setup Details:

• Plane Vigilant C1 V tail – fibreglass and carbon fibre construction with 3m wingspan.
• Stock Vigilant C1 motor – 300kVa
• Pixhawk autopilot
• Panasonic 18650B Li Ion batteries. 6S 9P = 30600mAh.
• Aeronaut CAM Power Prop 13x12
• HobbyKing telemetry module
• HobbyKing power module
• Distance covered: 425km (264miles)
• Flight duration: 7hr 48 min.
• Average groundspeed 15.3m/s (55km/hr)
• AUW = 5.7kg (12.5lbs)
• Goteck DA2311T Servo
• ZTW 65A Gecko ESC

This fire in my home town is suspected to have been started by a LiPo. (Though that hasn't yet been confirmed by the fire investigation authorities.)

"A neighbour, who didn’t want to be named, says Les is a member of the Nelson Model Aero Club."

Thankfully the occupants are both safe, and fully insured, but boy they were lucky to get out alive. Imagine if this happened at night when they were asleep.

I store my LiPo's in fire proof bags in the house. I'll store them in fire proof bags in the garden shed from now on.

http://www.stuff.co.nz/nelson-mail/news/67536649/Intense-blaze-destroys-pairs-home

http://nelsonlive.co.nz/news/2015/03/fire-destroys-stoke-couples-home-2/

Today I flew my Cyclops EPO for an incredible 7 hours and 8 minutes, covering 301 km (301 km !!!) in one flight.

After flying my Maja for 126km I decided 200km would be my next challenge. I got the Cyclops with that in mind, it was very very efficient straight out of the box and after my first flight test I realised it was capable of much more.

I did 5 flight testing sessions where I tested different speeds, C of G positions and propellers. The data from my last two sessions suggested 300km was possible with good conditions so that became my goal.

I planned my mission with a couple of waypoint path options that I could switch between using do_jump. After a hand launch I switched to auto for a very gentle climb reaching 50m of altitude over about 2km. I flew a few laps of a 2.5km lap, before switching to a 3km lap and then a 3.5km one which used a do_jump command to fly continuous laps at 60m altitude.

To monitor my progress I’d made battery consumption schedules for 250, 280 and 300 km. My calculations said that I would need to run my batteries down to 10% remaining to reach 300 km. The first half of the flight was very calm and I was ahead of schedule. But the wind picked up in the afternoon and it became apparent that I might finish with less than 10%. I tried to help the situation in the last hour by varying my speed around the lap. I flew at 14 m/s for the head and cross wind sections, and dropped to 13 m/s when I had a tail wind. I hadn't done any calculations to support that, it just seemed that I could make the most of the tailwind section by dropping my power there a little.

I’d decided in advance to end the flight when the battery dropped to 12 V (3.0 V per cell) and I could see as I passed the 280 km and 290 km milestones that it really was going to be tight. The voltage was hovering either side of 12 V as I approached the 300 km mark so I knew it was time to bring it in, but I also knew that Mission Planner can underestimate the distance compared to the GPS log. I decided to fly to 303 km to be safe. The way the laps worked out it was 305 km when I hit the ground, and just as well because the GPS log came up as 301 km. If I’d come in when Mission Planner told me 303 I would have been member of the 299 club.

The telemetry log file is 47 MB (linked below) and Mission Planner crashed when I tried to create the KML file (I tried on three different machines). It did manage the GPX file thankfully.
Key specs:

• Cyclops E with V-tail
• APM 2.5
• Panasonic 18650B Li Ion batteries. 4S7P, 23,800 mAh
• Aeronaut 11x9 prop
• Hobbyking telemetry
• Distance covered: 301km (according to GPS log file, 305 km according to Mission Planner)
• Flight duration: 7 hr 8 min 10 sec
• Average groundspeed 41.7 km/hr

Log File (47MB)

Last month I detailed my plans and preparation for an attempt at a 100km flight in a blog here.

Well yesterday the weather was ideal and my preparations (nearly) complete so I went for it and achieved a flight distance of 126km in a time of 2 hr 46 min 40 sec.

I can't attach my log file here because it's too big. It's 15MB and there's a 7MB limit. Any ideas how I can share it?

I exported the KMZ (2014-01-28%2006-32-40.tlog.kmz) to Google Earth and generated the following images showing the flight path, and the altitude/speed trace with some of the vital statistics.

[Click image to enlarge]

The airframe is a Bormatec Maja with 2.2m wingspan. It’s not the most aerodynamic airframe, but its advantage is its payload capacity which allowed me to carry 21600 mAh 6P4S Li Ion batteries with ease.

I stripped out absolutely everything I didn't need including the obvious things like FPV cables in the wings, and thanks to some advice on my previous blog I also removed a few things I wouldn't have thought of such as the RC receiver case and airspeed sensor.

The advice I had from other DIYDrones users was invaluable but the biggest factor in improving the performance was the testing I did. For each variable I wanted to examine I would fly multiple laps at different settings then analyse the log files to find the best performing setup. I give more details on that in the original blog.

For the actual record attempt there were a few things I’d never done before. One was flying without the airspeed sensor (I had flown with it switched off, but never with it physically removed) and the other was the 4 cell batteries. Probably both those things were the cause of the trouble I had getting the plane to fly at the 13m/s (47km/hr) I wanted. Initially it was much too fast. Over the period of a few laps I adjusted the cruise throttle percentage, the cruise speed and the min and max speeds to much lower than I really wanted which bought the speed down (and pitch up) to where I wanted it.

Key Stats
• Distance: 126km (according to Google Earth)
• Duration: 2hr 46min 40 sec
• Airframe: Bormatec Maja
• Wingspan: 2.2 m
• AUW: 3.25 kg
• Battery capacity: 21,600 mAh
• Average Speed: 45.6 km/hr
• Top speed: 68.3 km/hr
• Minimum speed 40.5 km/hr
• Duration: 2hr 46min 40 sec
• Barometer creep: -6m

On the weekend I flew in support of a whale rescue at Farewell Spit in Golden Bay, New Zealand at the invitation of Project Jonah, a whale rescue NGO

https://www.facebook.com/projectjonah

About 60 pilot whales had stranded over night high up the beach. About 10 died or were euthanized and the surviving 50 were successfully re-floated at high tide around midday. The plan was for me to fly overhead and monitor their progress via FPV. If they headed out to sea then everybody could relax. If they headed back to the beach then we would have advance warning of where they were going and the rescuers could create a human chain to prevent them beaching again. 

As it turns out I wasn't much use, the whales beached again about 10 minutes before I got airborne. If I was half an hour earlier my UAV could have provided real time situational awareness that would have enabled the rescuers to swing into action.

Farewell Spit is a common site for whale strandings. The beach has a very gentle gradient, the distance between high tide and low tide is up to 2 km in places. The photo above was taken at low tide, a little over 1km away from the high tide mark. It's not apparent from the photo, but the whales were grounded just 100m from deep water. My contact person was the Project Jonah general manager, he told me that the proximity to the deep water would have meant a human chain could have been particularly effective at preventing them from stranding.

The wind was strong the whole time I was on site with gusts to up to 50km/hr. I flew one mission and it was the bumpiest flight I've ever done. The flight log shows it got buffeted to 60 degrees of roll (it felt like 90) as I was taking off in stabilize mode. It got buffeted to 80 degrees later in loiter mode. The plane has a normal cruise speed of 40km hr so I struggled to make headway upwind and I hit 100km/hr at one point downwind. My gimbal could tilt but not roll so the wild movement made the picture pretty unstable but the whales and rescuers were clearly visible from the air. It was live FPV only, no recording to share here unfortunately. I flew in auto mode initially and used guided mode and loiter to remain above the area the whales were. My airframe (Bormatec Maja, 2.2m wingspan) wasn't really the best airframe for the conditions. It was too slow in flight speed and too docile in maneuverability. I would say a small flying wing might be best.

I packed up my gear after my flight, then put on my wetsuit and rushed down the beach to help with the rescue effort.

The situation when I arrived was much as is shown in the photo above which shows about a quarter or third of all the whales affected. I was directed to help a group of 5 whales and I worked with three others for an hour or so keeping them covered (the sheets blew off in the wind), keeping them wet and cool, and digging trenches by hand under to allow their pectoral fins to rest in a more natural position. The whole point was to keep them alive and in good condition until they could be re-floated when the tide came in. I wish I could have stayed longer, many people had been there all day, and would be until dark.

It was an experience that I'll remember my whole life. There were so many feelings that changed from moment to moment as I worked and took in the situation. Mostly I felt pride or a sense of service from being there with my sleeves rolled up, but that alternated with frustration, why had the whales beached themselves? What's the point of all that effort if they're just going to do it again once they're re-floated (this was already the third time in two days)?

But the thing that struck me the most was a discussion I had with one of the Project Jonah co-coordinators. I told him they could buy a reasonable FPV setup for under $1000. He said that sounded really nice but as a volunteer organisation they couldn't afford it. He said that he paid for his own flights down from Auckland (about 1000km away) and when they need to hire a spotter plane to track the whales they paid for that from their own pockets. It's incredible to meet people that have such passion. I'd driven 200km to be there and spent most of a day, but I suddenly felt dwarfed standing beside him.

My point in writing this blog was to tell about the potential uses for a UAV and relate my day saving the whales. But I can't help myself inviting donations for Project Jonah. If any manufacturer(s), or individual(s) were prepared to donate a suitable airframe, and components then I'd donate my time to set it up and train them in its use. (I can't drop everything to attend a stranding so if it's going to work it will have to be Project Jonah owning and operating it). 

By way of a progress update it's a little over 24 hours since I was there. The whales have been floated, and are swimming in deep water but are still milling about not far from the danger zone. Only time will tell if they strand again or head out to sea. See the Project Jonah Facebook for progress updates and more info. https://www.facebook.com/projectjonah

I'd like to fly my plane 100km. Partly to earn the cool badge, but mostly to see if I can.

The airframe is a Bormatec Maja airframe which is made from EPP, has a wingspan of 2.2m and an empty weight of 2kg.

I've been tuning it over the last several months to get the best efficiency I can. I've tested dozens of different setups such as props, motors, PID settings, C of G positions etc by flying a circuit in auto mode. By post-analyzing the telemetry data in Excel I can look at the wattage (and speed, pitch etc) for each lap to see what effect the particular setup had on efficiency. I found the AVERAGEIFS function invaluable to pull data from the telemetry csv file and calculate the average values per lap.

The two biggest breakthroughs were finding the best C of G (20% improvement) and best motor and prop combo (50% improvement in several steps, thanks to Reto Buettner and his expertise for helping achieve the last 20%).

Some of the smaller details I've been working on include:

• Fairings (seen below in front and behind the wing mount).
• Swapping the protruding telemetry antenna for a smaller monopole one (rfdesign.com.au ).
• Filling gaps, like the hole left by removing the antenna, the flaps hinge gap, around the aileron servos etc.

To calculate the maximum range I used a formula that calculates how adding weight affects speed, drag and power consumption. The manufacturer says the Maja can carry a payload of 1.5kg which allows me 4 x 5000 mAh (1.6kg of batteries, AUW of 3.6kg). I calculated a maximum range of 85 km if I run the batteries down to 20% reserve. (I don't want to wreck my batteries but the range becomes 102km if I run them down to 10%.)

I've done one round of flight testing with 4 x 5000 mAh on board and the results were slightly better than my calculations. At an airspeed of 13 m/s it consumed 89 W (8.2 A @ 10.9 V). Extrapolating that out gives a maximum range of 89km. Just short of the ton, but still worth a crack.

Both the manufacturer and another experienced Maja pilot expressed concern about making it any heavier, but I'm tempted because my calculation for 5 batteries (AUW 4.0kg) is a range of 103km. My experience with 4 batteries was good so 5 doesn't seem out of the question. I’m still undecided whether I should go for 5 or look for further improvements with 4.

I've got three more small things to try.

• The EPP surface isn't very smooth so I want to cover the wings (I've got some CP Laminating Film - 1.7 Mil on the way).
• Doing something about the white plastic rods used to hold the wings on. They're very convenient, but I'll find something that doesn't stick up like that. I'm not sure that I'm brave enough to trim the coroplast trim to the wing.
• Moving the Pitot tube to the wing so the tubes and brackets don't cause drag.

I think I’ll make an attempt with 4 batteries anyway. I'll happily land with 20% reserve if it looks like my 89km calculation is correct. But if conditions are very good I might get lucky.

Any other suggestions for how to improve the range appreciated.