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Posted by blitzen | Apr 03, 2019 @ 11:02 AM | 1,225 Views
Over the past 5 months Iíve built a series of micro RC planes. It has given me the opportunity to try the things I have read about. And, test my own ideas. All of the planes have been variants of a simple foam board profile design. I have read about how vortex generators are used to improve STOL performance. Looking at photographs of planes with low aspect wings and VGs attached, I have estimated the size and position of the vanes on my RC model. A combination of 30 micro vanes of various lengths protrude slightly from the surface. The vanes are short, a small fraction of the airfoil thickness. It starts with vortex generators on the top side of the wings along the leading edges. Then on the underside, two longer vanes near each wingtip. Lastly, a few vanes on both sides of the vertical stabilizer. That is a lot of guesswork and Iím sure my method is laughable to hobbyists that really know what they are doing. So in the spirit of blind ignorance, Iím pressing on. The vanes will be cut from thin plastic and embedded into the surfaces.
Posted by blitzen | Feb 23, 2019 @ 05:15 PM | 1,769 Views
After several goofball attempts, I failed to convert a small chuck glider to a viable powered RC plane. I didn't completely abandoning my idea. After testing weighted gliders, I completed a model that flew very well. But, the foam board I purchased locally is poor quality. Again, plans change. Having to reinforce and tape the fuselage made the plane heavier and shifted the load. That unfortunately changed the dynamics. Taping the battery to the bottom like a drop tank was not planned either. The plane still glides okay. The control surfaces are the entire trailing edges of the wing and stabilizer. They're very effective. The elevator and aileron channels are mixed to control the elevons. A servo was added for the rudder so there is full control. Except for the rudder servo, the 4 channel receiver compacts everything that’s need onto one board. It works adequately. The size, weight and cost were less than buying separate pieces. Of course the small size (8” wingspan) restricts the choice of components. There are no self correcting characteristics but once the plane is at cruising speed, it is steady and easier to manage. An oversized battery powers the insanely fast brushed motor for about 7 minutes. After that the motor is hot. The heat hasn’t affected the adhesive and the motor is still solidly in place. Unlike a gear driven propeller, the little prop spins extremely fast. There is a lot of motor torque. When launching, the throttle is only increased as the forward velocity increases. Otherwise the little plane will roll over. Traveling at a high speed the sticks become hyper sensitive. I’ll just mention setting rates, expo and throttle curve on the transmitter.
Posted by blitzen | Jan 18, 2019 @ 06:06 PM | 2,222 Views
My last post was about an ultra micro plane and a problem with a fried motor. A new motor was mounted and working normally. Less than a minute after the plane was back in the air, it suddenly wanted to gain altitude. For a moment, I thought that something was wrong with the elevons. But then I realized the throttle stick had no effect. The plane must have been flying close to full speed by the time I turned off the TX. After a few seconds the plane dived. On the ground, the motor spun slowly until the battery was disconnected. The smell of burnt circuits lingered, The plane survived with minimal damage but the board can't be removed without breaking the plane apart. So, that ends that.
Posted by blitzen | Jan 12, 2019 @ 02:00 PM | 2,192 Views
It all started with a phenomenal chuck glider. The plan was to transform the glider into a RC plane. I've never built a plane before. A little plane didn't seem overly ambitious. My feeble attempt flew like a wounded duck. I salvaged the parts, swallowed my pride and went on to build something more conventional. This time the components are recessed into the wing and fuselage of the basic glider. That idea seemed straightforward enough. Mounting the board and servo between the wing and fuselage wasn't that easy. The plane needed to remain balanced too. The combo receiver board has two onboard servos that are connected to the elevons. Another servo was added for the rudder. The servos are in line with the control horns and the push rods have no slop. The control surfaces have quite a sweep and are 100% of the trailing edges. The flat trapezoidal wing has a 3 degree forward incline and no dehireal. I have had only a few flight sessions because of unsettled weather. I was mainly looking at how everything behaved and made adjustments to the transmitter settings. On my last outing I had problems. The motor had been slipping in the mount and had been turning little by little. Finally, the wires behind it twisted together so tightly that a short occured. The motor became blazing hot and it fell off. I'll be eliminating the mount and gluing the new motor further back in the fuselage. Glide tests actually showed an improvement so I don't need to fiddle with the CG. Hopefully the new battery for my hat cam will arrive soon and I'll have a video to post.
Posted by blitzen | Dec 31, 2018 @ 02:04 AM | 2,630 Views
My 2018 resolution was to keep this blog active for a year. This is the thirtieth post. I'm gratified that it has occasionally been read.
This past year I started experimenting with indoor gliders and ultra micro planes. Just last month, I scratch built my first RC plane. I made plenty of mistakes with the design and construction. It was only a limited success. Since then, I've been working on a new design and the first test flight will be on New Year's day
Posted by blitzen | Dec 07, 2018 @ 08:46 AM | 2,838 Views
The plane is based on a chuck glider designed by NASA. My first experiment was a controlled glider. It was 25% larger and 40% lighter than this powered plane. The plane is powerful enough for a moderate climb. Coordinated turns are smooth and graceful. I expected the plane to be hard to fly, it wasn’t. PS foam dents easily. After only a few days, it was looking dirty and beat up. The motor is still straight but the nose has damage which makes it look asymmetrical. I might build a 2nd version of this plane. The wish list is a tougher skin and landing gear.
Wingspan: 180mm. Material: PS foam. RC: 4 channel 2.4G receiver. Mechanical: 3 servos, Brush motor and 2 blade propeller. Power: 1S 3.8V LiPo.
Step 1.Top and side views were drawn on a plain sheet of paper. Dimensions and sizes were adjusted when the plan was exploded into pieces and parts. Paper templates were cut out and taped to polystyrene foam. Then the shapes were traced with a hot wire foam cutter. Elevons and a rudder parts were cut with a razor and hinged with tape.
Step 2. The bottom and sides of the fuselage are glued. With those pieces connected, I started forming the nose. There are angles, curves plus a motor that all need to align correctly. The top of the fuselage is left open for now.
Step 3. A plastic motor mount is hot glued to a foam support in the nose. The motor is friction fit into the mount. A 0720, 15000KV brushed motor turns a 57mm, 2 blade prop. A maximum 17g of thrust is produced. More...Continue Reading
Posted by blitzen | Oct 15, 2018 @ 12:50 PM | 2,949 Views
I have improved my polystyrene foam cutter. The cost to build was about $10. Using household tools, a drill, soldering iron and glue gun it was complete in a couple of hours. The size accommodates polystyrene foam up to 1" thick. It is portable, powered by 2 alkaline D cell batteries. 3 inches of very thin steel wire is heated by resistance to just beyond the temperature polystyrene transitions. Polystyrene is safely cut in a ventilated area. The heat is minimized to avoid unhealthy fumes. As a result, cutting speed is more or less 9 inches per minute depending on the size and density of the PS. The cut is barely larger than the diameter of the resistance wire so detailed and accurately sized pieces and voids can be achieved. It also cuts thin molded PS (recycling symbol 6). The platform lifts off to change the batteries or resistance wire.
Resembling a pizza box, a 12" square frame made of 1.5" x .5" poplar with a .25" paper board top and bottom. The lumber was cut with a small hand saw. The top board is left unattached and small blocks are glued to the underside which keeps the top in position on the frame.
A light steel rod is bent at a right angle. One end of the rod is fitted into a hole in the frame and held with a set screw. The point of the screw tip is ground off. The arm is parallel to the surface at 2" above. The negative battery wire (22 AWG) is inconspicuously soldered to the rod using a heavy soldering iron. The resistance...Continue Reading
Posted by blitzen | Sep 21, 2018 @ 11:07 AM | 2,701 Views
Brushless Micro Foam Quadcopter DIY
Since it's introduction last week, I've been bouncing it around the apartment. I began flying at ever increasing speeds and eventually made a mistake. The hard impact fractured the foam in several places but the propellers and motors were protected. One of the screws had broken loose from the camera's shell. The camera was undisturbed. More importantly, the quad didnít mar anything that it hit. For now, cracks have been glued and the loose screw is repaired. Although my repair work is hardly noticeable, I donít trust the integrity of glued foam. Anyway, the damaged part is a roughly cut prototype not the final version of it.
Posted by blitzen | Sep 16, 2018 @ 04:03 PM | 3,486 Views
The Cherry Bomb measures 5" x 5" x 1.75Ē and weighs 30 grams. Basically, an impact resistant foam guard is bolted on. The protective rings are strengthened by the nearly Invisible clear plastic ducting. The assembly has proven to be durable. The rest of the unit can be completely disassembled if necessary. A simplified carbon fiber frame supports the motors. The F3 flight control / 4 x ESC board is isolated by vibration dampened mounting. There is more than enough room to tuck in a mini receiver. An OSD ready, 25 mW AIO FPV camera is mounted near the center of gravity under the protective shell. The guard and props are in the cameraís view. Unfortunately, that is unavoidable. The 46mm props and 0703 brushless motors are a powerful and efficient combination. A 250 mAh, 3.8V HV LiPo lasts for over 3 minutes. The battery adds 6g.
Posted by blitzen | Aug 14, 2018 @ 10:26 PM | 2,790 Views
Itís been great fun flying around the neighborhood, the park and playground this summer. But thanks to the RC Groups field finder, I found a bigger flying field that is accessible by public transit and only 20 minutes away. There are 4 soccer fields placed end to end along the river. Iím guessing they are reserved by clubs. There are shaded areas, picnic tables, restrooms, a parking lot and cold bottled water vending machines too. The whole place was deserted when I was there. I only saw friendly grounds keepers. One seemed accustomed to RC modelers asking if it was okay to fly. ďNo dogs and donít feed the geeseĒ. Thatís all he cared about. There is a fee to park but I got off a bus right outside the gates and itís free to walk in.
Posted by blitzen | Aug 11, 2018 @ 11:22 AM | 3,113 Views
It was a warm Summer evening. I put on bug repellant and went outside. This was the first full battery flight of a lightweight (75g gross) micro quad copter that I had recently built. The first couple of minutes was line of sight. Onboard LED indicators make it bright enough to track in the dark but didn't help with orientation. The fast motors and short props spin smoothly and quietly so I wasn't disturbing the peace. A ďthrottle punchĒ was respectable and after a few flips and funnels it was time to try the goggles. Since the flight control board has Betaflight OSD the peripheral screens are redundant and are turned off. Unfortunately, the camera isnít configurable through the Betaflight OSD menu. A wired dongle is needed to change itís settings. Using it was inconvenient enough that Iím already browsing for another camera. Taking off into the darkness, the clarity and brightness of the image was actually disappointing. This could be because Iím not adjusting the camera correctly. The FrSky X7 radio can take advantage of the 16 channels on the SBUS receiver. in other words, I need to remember or label the switches on the radio. There is no telemetry but the ďfull rangeĒ receiver shows RSSI in Betaflight OSD. I had previously set up 3 profiles but chose the BF 3.4.0 default PIDs with the rates changed to my liking. Flying around obstacles closer to the ground a propeller clipped a shrubbery. I was unaware that a blade broke off until afterward. Economy and distribution of power were challenges when building this. Iím happy that a small 2S LiPo lasted almost 7 minutes.
Posted by blitzen | Jul 31, 2018 @ 11:03 AM | 4,085 Views
July 31st. Over the course of this month everything except for the frame, motors and camera had been changed out. The quadcopter has been put together, flown and taken apart a dozen times. This last change was quick and easy. Swapping out the VTX was done to reduce the load current. It worked and the image quality seemed improved too. But, there is a problem. I eventually figured out that the voltage from this new VTX to the camera is now dropping slightly below 5V. And, that isn't enough. Today, Iíll rework that and hopefully everything will be copacetic. If I shot a build video about this, it would be 4 hours long.
Posted by blitzen | Jul 27, 2018 @ 10:13 PM | 2,991 Views
My last post was celebratory. I had finished building a micro FPV quadcopter. For various reasons, it had taken almost a month and I was glad it was finally done. Well, the celebration was early. I had overlooked the flight controller BEC specification. It could only handle half as much current as I thought. So, the FPV system I put together was causing a brown out. An additional BEC wonít fit so finding a lighter duty VTX became crucial. I eventually found one with a lower input current. I hope the specs are right. It will be here someday next week.
Posted by blitzen | Jul 25, 2018 @ 12:13 AM | 3,193 Views
I've just finished the final flight testing for this is one. It's done!
Alfa-Genie 110mm Frame- This is a popular design theme these days. The CF frame kit has a 2.5mm base, 1.5mm top and pieces to mount a 19mm camera. Made of quality material that is nicely cut. Aluminum standoffs are 20mm.,
Halo F3 (Omnibus) Flight Controller and BS410 four in one 10A (BLHeli S) ESC Fly Tower Stack- Flight control and ESC boards are pre-assembled into a 20mm x 20mm stack. And, a LC filter is in line to the flight control board.
Crazepony BR1103 10000KV Motors & 2035 4 blade Propellers- These motors are running very smoothly (D Shot & Dynamic Filtering). The open motor bell is without screw holes so the propeller simply pushes on to the 1.5m shaft. The factory made bullnose props are well balanced.
FrSky XM+ 2.4G Diversity Receiver- A small "full range" 16 Ch. SBUS RX without telemetry. The firmware was flashed so RSSI can be seen in BetaFlight OSD.
Foxeer Micro Arrow Pro FPV Cam- A "better" camera with low light sensitivity is the whole purpose behind building this quadcopter. It has an on screen display and a detachable dongle to change settings.
Eachine VTX03 Video TX and Antenna- The frame requires a split cam and VTX. The unit is basic but has switchable power and a single character LED indicator. The light-duty antenna is attached with an IPEX snap on connector. The board gets very hot even at low power so it is mounted as far away from the rest of the electronics as possible.
7.4V 400mAh 30C- JST and balance charger connection. The flight times are about 6 minutes.
The weight is just 76g including the LiPo battery
Posted by blitzen | Jun 22, 2018 @ 11:50 AM | 3,582 Views
Last night I was out flying after dark again. Iím still amazed at the view through the goggles. The twilight appearance of everything is erie. The sky has been clear which helps the visibility. Of course where the man made ambient light is stronger, there is less noise in the image. My little 1S drone is quiet, unobtrusive and dimly lit. Iíve spotted some wildlife around neighborhood. A bat catching bugs under a street lamp and a skunk rummaging in the dark recesses. A few blocks (300m) down the avenue, the light from the bars and restaurants looks very bright. Iíd like to checkout the ďwildlife" down there in a future (late night) adventure. Tonightís forecast is cloudy and Iím interested to see the effect of that.
Posted by blitzen | Jun 15, 2018 @ 10:29 PM | 3,641 Views
Tonight was the first time I've tried flying FPV outside at night. I flew a little brushless micro with a very inexpensive AIO VTX/Cam. The camera shows a grainy, washed out image in low light indoors. Outside it's grainy too but I could see pretty well. The resolution is poor. I'm in the camera's view but I look like a fuzzy blob in the picture. There is a lot of light pollution and the camera picks up on it. With the camera pointing towards Manhattan the sky is actually bright. Also, there is some color to the objects. This was about 45 minutes after sunset. To my naked eyes it was dark out there. Anyway, this is something I want to do more often.
Posted by blitzen | Jun 12, 2018 @ 12:59 PM | 2,704 Views
2 cups of coffee. New batteries and a beautiful spring morning. New power for the goggles and transmitter too. I was flying fully charged.
Posted by blitzen | May 25, 2018 @ 01:50 PM | 3,625 Views
I had been reading about building RC electronics like ESCs and receivers. While beyond my ability, I think it is interesting to read about what makes these things work. The fishpepper uSKY receiver was of particular interest to me because of the 10mm by 12mm size. While the tiny SBUS receiver started as a hack/project, assembled versions had become available here and there. I had come across a professionally assembled version from a factory in China. It looks identical to one now sold on Banggood. Anyway, the receiver operates at 5V. Compatible with the FrSky D8 SBUS protocol, binding to the Q X7 transmitter was simple. The assembly is neat, clean and a bind button has been added. The antenna wire is a generous 144mm long. So it was trimmed to an appropriate size for my quad. After insulating with heat shrink, the tiny receiver was tucked in between the standoffs of a 16mm stack. First tested inside, the uSKY worked reliably. Outside, the control distance is said to reach 200m. The 25 mW FPV signal only carries about 100m+ but the RSSI was still strong at that point.
Note: Betaflight 3.3.1 CLI syntax "set serialrx_inverted = ONĒ now replaces the old "set sbus_inversion = OFFĒ
To purchase a fully assembled receiver go to and search for 8CH-SUBS. Yes, they misspelled SBUS in the URL/description. Or, for more information about the open source check out
Posted by blitzen | May 19, 2018 @ 03:28 PM | 3,491 Views
About a month ago I wrote about a micro size drone kit. The drone's frame isnít so small (90mm) but the whole thing only weighs a few grams more than a ďTiny WhoopĒ. I donít have a yard or a field nearby. But, Iíve got a bench outside my building and that is where Iíve been. I was astonished by the drones outstanding performance outdoors. The FPV signal carries for just over a block (100m). Itís great fun flying around the neighborhood. Over the past few weeks the configuration has been tweaked to the point of perfection. The combination F3 flight controller and 4 in 1 ESC is working flawlessly. The 0703 15000KV brushless motors are very quiet and after the flight they're still cold. I believe this is due to the DShot 600 ESC protocol and Dynamic Filtering in Betaflight. The motors and 3 blade props produce an abundant amount of thrust and the drone could afford to gain a little weight. So today, Iím building another Happymodel Trainer90 and I will continue to experiment.
Posted by blitzen | May 13, 2018 @ 08:02 PM | 3,705 Views
This is very similar but not identical to another flight control board with the same description. The package includes a battery connector and buzzer. The lowest price was from Banggood (on sale $23.49).
The Fusion X3... is a compact, lightweight option for 1S brushless multi rotor DIY. This is not a corner mount ďwhoopĒ style board. Instead, this is rectangular and typically mounted on 4 standoffs attached to a frame part. It can handle a variety of 1S brushless motors and 3.7V and 3.8V LiPo batteries. Both the flight control and ESC are configurable and have fairly recent and stable versions of their firmware installed. There is 5V for a receiver (PPM, SBUS and IBUS), VTX, buzzer and LED. But, no 3.3V for a Spektrum receiver. Soldering the peripherals and motors takes forethought because there are connections on the top and bottom of the board. The 5A ESCs are big enough to handle the current that passes through 06xx and 07xx motors.
CPU: STM32F303CCT6 (72MHZ, 256K FLASH) MPU-6000 6DOF (SPI connection)
Power supply: 3.7V 1S
Voltage detection, alarm and 5V/1A step up regulator
Betaflight programmable OSD, buzzer and LED Strip
Receiver protocols: PPM, SBUS, IBUS, Spektrum DSM2 / DSMX, 1024/2048.
Betaflight Omni 3.2 firmware
BLHeliSuite programmable BLHeli_S 5A ESC (6A 3 sec. peak) Supports D-shot150, D-shot300, D-shot 600, Oneshot125, Multishot, PWM
Measures 28mm x 30mm and weighs 3.1g.
2.5M screw hole spacing: 16mm x 16mm