It's official. Guinness World Records validated the flight (see link under Flight 1).
Two flights were achieved to demonstrate that multi-rotor aircraft can stay in the air carrying a payload for a long period of time. While 20 minute flights were considered long in 2014, these demonstration flights show that 1 hour flights can be the norm. Imagine the increase in commercial applications when it is common for ships to stay in the air for an hour or more carrying different payloads. It's just a matter of finding good rotors (Tiger), flight control electronics (3DR), batteries (Panasonic Li-Ion), ESCs, and removing unnecessary weight. Once industry realizes the importance of performance, we will also see a jump in rotor and ESC net-lift efficiency (lift after it gets itself off the ground first).
Flight 1 – Guinness World Record for Longest Electric RC Multicopter Flight (Duration). Pending Guinness review.
- Ship Name, Rufous
- A hover that stays within view of the stationary video camera
- 1 ½ hrs (97 minutes 23 seconds) on 8/21/2014 @ about 4 meters above open level ground (well above ground effect and without use of thermals or updrafts)
- Hover, while not impressive nor useful, does require more energy than typical flight speeds and as such, a good first test.
- Pixhawk Flight Log (Time, GPS, Altitude, Speed, Volts, Amps): Guinness Flight
- Video of the Guinness record
- Guinness Record Book
- Time Lapse (GoPro) of the Guinness record.
- Ship Secrets
Earth view of the hover breaking the world record.
The officials: Michael Allen (expert in UAV flight control; Cloud Cap Technology), Brett Faike (UAV extraordinaire; teaches UAV tech at local schools; gave FPV demo after flight), Forrest (pilot in training), and Kirby Neumann-Rae (editor of the Hood River News).
Celebrating surpassing the old record of 80 minutes (ahhh ... hey pilot ... a little less champagne and eyes on the copter ... it's not time to prune the orchard yet!). Bud, not shown, was taking photos. Hope you got some champagne Bud!
Co-pilot, Dr Carie Frantz ... yes this amazing looking lass is single, is an unreal outdoor bad-ass, and has a great job in case you were wondering. Thanks for keeping pops sane Carie.
Posting the final time (for the final application to Guinness, I requested that 4 seconds be taken off because some blades of grass were brushed prior to the ship finally giving up and setting down. An interesting note on the battery:
o The Li-Ion batteries used are rechargeable (flight was on about the 8th recharge).
o Running Li-Ion batteries down to where the ship drops out of the sky does not hurt them if the ship mass and battery voltage is engineered to invoke that event before voltage runs down too low.
o A few days later, Flight 2 was made using the same battery pack with the ship carrying a camera (see Flight 2 next).
o Li-Ion are low C discharge (not 30 or 20 or 10 ... think about 1 C). The chemical barrier will break down if amp draw is too high. This causes the ship to loose altitude. And if there isn't enough altitude for the battery to recover, crash. As an example, using a 4S5P battery pack (about 15000mAh), Rufous hovers and flies at moderate speed at about 8 to 10 amps depending on payload and flight demand and does great even in moderate winds. Rufous has even flown 60 mph (97 kph) on the same Li-Ion battery pack. However, get up to 15+ amps turning a sharp high-speed corner and the battery chemical barrier locks up in about 2 seconds (yes I've had to rebuild a few times before I figured this out). So caution. Do the calculations. Try to design a safe ship that stays in the air at 2x the amp usage at hover.
Flight 2 – Performance demonstration flight (actual flight versus stationary while carrying a payloads)
- Time aloft goal of 1 ½ hr; so far 82.9 minutes
- Distance traveled goal of 10 km; so far 14.4km (9 miles)
- Elevation gain (cumulative) goal 300 meters; so far 378 m (1242 ft)
- Speed (max) goal 18 m/s (40 mph); so far 9 m/s (20 mph)
- Speed (typical) so far 2.3 m/s (5 mph)
- Payloads GoPro Hero 3+ and 3DR Telemetry Module
- Flight Log (Time, GPS, Altitude, Speed, Volts, Amps) Performance Flight
- Video coming soon
[note: will try to beat 90 minutes carrying a camera when I get back from Sri Lanka]
Earth View showing the flight path of the performance demonstration over my orchard.
Photo taken by Brett Faike, a local multi-copter flying legend, of the flight area (man-cave on left and princess palace on right). He treated the witnesses of the Guinness record to FPV flights afterwards using two sets of goggles so we could "ride" along (keeping the ship within visual range and over my farm, of course).
Flight #2 (with camera and telemetry payloads), Elevation Profile.
Flight #2 (with camera and telemetry payloads), Watt Profile.
Flight #2 (with camera and telemetry payloads), Speed Profile. The wind speeds were about 2 - 4 m/s from the north..
- Design/Engineering Forrest Frantz
- EE/Flight Engineering Jim Frantz
- Test Marty Frantz
- Pilot Forrest Frantz
- Copilot Carie Frantz
Acting Guinness Judges/Timers
- KirbyKeumann-Rea Hood River News Editor
- Michael Allen Cloud Cap Technologies Flight Control Software
- Brett Faike Multi-Rotor Extraordinaire Software Developer
Ship Summary: 1.65 kg (w/ camera & telemetry)
- Frame Quad Carbon tube w/ open front for photography 62 g
- Flight Controller 3DR Pixhawk + 3DR Power Module 34 g
- Motors T-Motor MN3508-29 380KV 328 g
- Propellers T-Motor Carbon 16 x 5.4 116 g
- ESC Afro 20A 31 g
- Batteries Rechargeable Panasonic NCR18650B 4S5P 930 g
- Camera GoPRo Hero 3+ 76 g
- Telemetry 3DR Radio V2 19 g
- Wires & Misc Long wires runs were magnetic wire 54 g
Design Elements of Note:
- The electronics platform (EP) was eliminated to save weight (previous EP added 8 grams). The battery doubled as the EP. The flight controller (FC) was bonded directly to the battery, which was bonded directly to the frame. The battery has a strong electro-magnetic field around it. 3DR deals with this issue by putting the sensitive elements, the GPS antenna and Magnometer, separate so it can be placed away from the battery. In this case the GPS/Compass was bonded to the starboard-fore motor arm away from the battery. This is a testimony to the excellent design of the FC as it did its job that close to a large battery. Even though this worked, it is not recommended nor fully tested.
- The ESC have their heat sinks removed. To ensure cooling, the ESCs were placed directly under the tips of the propellers to get positive prop wash. The loss in lift is much lower than the loss in weight. To help protect from shorts, spray the ESC with electrical silicone.
- Wiring in right sized. The normal EE rule of 3% tolerated loss is put aside. The rule is replaced by physics of electrical transmission. A larger wire area cross-section produces less heat that is measurable in watts. And a larger wire area cross-section weighs more thus taking more watts to lift it. Thus watt usage can be calculated for all wire sizes and thus optimized. Some wire insulation is weak or can break down in sunlight. Magnetic wire was used where possible. But multi-wire strands are recommended to prevent wire breakage due to stress aging.
- Li-Ion batteries are about 50% more efficient (watts hours/gram) than LiPo for multi-rotor flight.
- Metal screws/nuts/washers replaced with nylon. The only exception are the propeller screws which are aluminum.
- Metal screws/nuts/washers and clamps replaced by bonded parts.
- Gussets, screws/nuts/washers, and plates replaced by continuous masts and bonding.
- Metal spacers replaced by short nylon spacers.
- The most efficient propellers and motors were used – Tiger T-Motor.
- Props and motors statically and then dynamically balanced.
- Vibration Average Score 0.05 gs.
- Stability Score: 0.14 degrees.
- Photography see test photos
Photo taken from tripod (baseline) with GoPro Hero 3+ at med 7m.
Photo taken from Rufous. The camera was hard mounted, so now need to work on camera isolation that works.
Test Flight Highlights: Prior to “Flight 1” the ship crashed three times.
Crash 1 – Tried saving 2 grams by using Single Ply Carbon Skin Nomex core sandwich panels for motor mounts. The Nomex core on one motor sheared causing a cascading event where all of the motors sheared. Picture the ship moving away in an uncontrolled fashion with one motor suddenly floating away and quickly followed by the other three motors as the frame and battery kept flying in a deep descent.
Crash 2 – Really stupid piloting. I cut power after a landing but forgot to disengage the motors (throttle lower left). As I bent over the ship, my belly pressed the throttle to full and I got a face full. Luckily wearing protective goggles and thick clothing. Sometimes it takes a hard lesson to learn – always disengage the motors and the first thing one does when approaching the ship is to push the red button on the Pixhawk.
Crash 3 – Had been suspicious of one motor mount bond (didn’t sand all surfaces on all the mounts). The suspicions came true as one motor left the motor mast and the ship impaled itself into the lawn (photo below) after some high speed runs that loosened the faulty bond. This crash broke one of the motor masts. The motors are held on with nylon screws that are sized to shear off without harming the frame. This works most of the time, but not this time.
Anyone interested in beating this record (the 100 minutes mark is itching to be broken), friend me and I'll gladly pass along what you need to do to satisfy Guinness. I only ask that we are gentlemen and set records using engineering and piloting skill minimizing the use of ground lift (e.g., please avoid a hover off of a hot tar roof above a heated wall or on a side of a hill/ridge or in ground effect). We want to show industry what is possible under normal flight conditions. I also ask that you fully disclose your ship so we can all learn from what you achieved. Thanks.
If you have any engineering questions, I'll will answer them below.