Now called the N3UTRON thanks to YouTuber Richard from 28th St. Air Land & Sea. "why not go all the way? it’s the N3UTRON. its a subtle reference to Ed’s photon, the u glider 3 channel, and andrew’s last name"
Here are the dimension of a 3 channel motor glider made using 3mm and 6mm depron and a woven CF
arrow shaft.
Armin wing construction with 6 x 1mm CF strip spar.
HobbyKing contact glue and hot glue.
Document laminating film wing and tail covering. Scotch Tough tape fuselage covering.
Flying weight is 300g with a 950mAH 2S LiPo
Motor and 5 x 3" prop from the U-Glider
Spring / Pull control
2 x 13g metal geared servos
12A ESC
Wingspan 140cm.
Chord width 14cm.
Chord thickness 14mm
3mm depron version of the wonderful little twin boom Eachine Micro Skyhunter.
Dimensions are similar to the original but with a slimmer fuselage.
1300mAH 3S battery and FPV gear.
CG best around 35mm.
The final version has a shorter nose, reinforced horizontal stab and rounded wing tips
This is the story of my awesome X UAV One 1800mm wingspan V-Tail sloper.
It was designed to be a pusher FPV cruiser with a unique prop drive mechanism that encircles the boom. However the boom prop gear box was way to noisy and caused vibrations. Bad for stealthy flying and onboard video.
This kit was sent to me by BANGGOOD for review.
While waiting for the motor to arrive I decided to try it as a sloper.
Actually I always intended to reconfigure it for sloping once the review was done.
The poorly designed gearbox really became apparent during my motor maiden flight.
Once that was out of the way it was time to try a tractor motor setup.
Not so good for FPV with the prop in front of the camera, but a much better flight experience.
And finally as a pure sloper with slimmed down fuselage and longer nose,
made from coreplast, hot glue and gaffer tape.
It is now a brilliant sloper that works in light wind, less than 10kn here, and will ballast up nicely for strong winds.
In really strong winds, like 25kn, it was obvious that the single boom V-tail design was still too flexy. So here's the next version.
I doubled the tail boom and changed to a conventional cross tail. At this stage I have no rudder, which works fine for speed runs. If I wanted more aerobatic performance from this glider a rudder would be essential.
I've added balsa fillets at the tail join for a bit more strength.
It's all much stiffer and is working well. So far I have only flown in a 15kn breeze, can't wait for a decent blow.
For the last 2 weeks the wind strength has rarely dropped below 20kn. To keep flying I needed to
design something that could handle strong winds. The obvious candidate was a speedy slope racer.
The balsa-pod version of my Ultralight Sloper was available because it was superseded by the mad-flipping Fusion. Here are the mods needed to transform it into a high wind speedster.
V-Tail 1
Many slope racers use a V-Tail, and I had never tried one, so that was my first mod. I used tape covered 3mm balsa, hot glue and guessed the dimensions. The tail servos are down on the tail, which is not ideal. Not so much for the extra tail weight but the added aero drag.
It flew OK but did not track well at all, drifting and wandering side to side. This prototype V-Tail did not provide enough vertical area.
V-Tail 2
Further reading here suggested that my V angle should be sharper, about 110º and the area needed to be increased.
That improved the tracking heaps but I noticed my tail boom was twisting alarmingly when operating the rudder, as demonstrated in the video below.
Rudder function on a V-Tail is not as effective as a conventional vertical rudder because the control surfaces are acting at an angle to the airflow. Most of the force goes into twisting the tail rather than moving it sideways, and the twist is in the wrong direction, a bit like adverse yaw from the ailerons.
Seems like V-Tails prefer more bank and yank style flying.
V-Tail 3
To increase the stiffness I shortened the tail boom by 150mm, cut 20cm off the 1.5m wing and 30mm off each tail section.
The shorter tail boom and smaller tail reduced the flex nicely resulting in much better speed and tracking.
In strong wind you can add ballast to give more momentum and penetration, which results in more speed. With a 2200mAH Lipo plus an extra 50g in metal washers it could handle 30kn flying crazy fast.
These photos show the final dimensions.
Flying weight with 1300mAH Lipo - 500g
Add ballast to taste
Wing - RG15 160mm chord
XPS foam hot wire cut
Covered with document laminating film
Servos - TGY9018 x 4
Strong wind V-Tail sloper overview and flights
Future design for more speed
For more speed I'll need to increase the tail stiffness further and reduce the drag.
My next high wind sloper design will have two tubes glued together for a stiffer tail boom and a conventional tail for less twisting. With a stiffer tail boom I should be able to place the servos in the fuselage for less drag, and run long push rods to the tail.
Weight is not a problem with these slopers, in fact more weight means more speed.
This design was inspired by a friend who wanted to take one of my "retired" planes to learn how to fly. So I gathered bits and pieces together and tried to come up with an easy to fly, crash proof trainer.
It only has rudder elevator and throttle, no ailerons. I wanted it to be as light as possible for slow and easy flight with a big energy absorbing nose and a tough fuselage.
The fuselage was shaped from a 50 x 100 x 370 block of XPS insulation foam and the tail planes are 8mm panels of the same foam. The boom is a Skyshark P4X 7.6mm tube.
The hotwire-cut 170mm clark y wing comes from rescued sections of the drowned Fokker (which now has new wings) Three x 360mm sections were glued together with the tips each raised 120mm. No spars are needed to hold the polyhedral due to the tape covering and large join surface area for gluing.
The nose is soft packing foam covered with tape and completely encases the 1300mAh Lipo battery.
The motor is the original Bixler 2, servos are cheap 9g HXTs, and it has a Plush 18A ESC and HobbyKing 3 channel receiver.
All up weight with the battery adds up to 550g, giving a slow continuous cruising flight time of over 30min.
This plane is very smooth and stable and with correct trim will fly hands off.
At this stage the nose, fuse and wings are almost bullet proof, but the tail planes are a bit too delicate. Thinner sheets of XPS foam are quite brittle so some kind of reinforcing is needed. Both the elevator and rudder have cracked during the test flights so I have added a 0.5 x 3mm CF spars.
Might be better to use depron or corflute for the tail.
Dimensions
Flight video - motor slope soaring
Build video
UPDATE 30 March 2016
After some tough flight testing by my dedicated student test pilot it became apparent that this tail
design was not crash proof enough.
So here is the new tougher tail design made from depron. The tail to boom join has extra foam fillets either side for more gluing area and to raise the elevator a little.
The new wing has more area and less polyhedral for smoother flight.
Two wings on the Tigermoth worked so well I had to take the next step...three wings.
The most famous triplane is the Red Baron's Fokker Dr1.
My wings are stiff enough not to need inter plane struts so I decided to stick to the familiar rubber band mounts. That meant I had to come up with a method for creating a rigid mount for the top wing. I recorded detailed build videos along the way.
SPECS
Top Wing - Top 1.1m, iron-on laminate and packing tape. 0.5 x 3mm CF spars
Middle and lower wings - 950mm and 900mm. packing tape. 0.5 x 3mm CF spars
Airfoil - 170mm Clark y
Fuselage - 6mm depron, 3mm ply nose, packing tape.
I have never been much interested in scale model planes apart from the Tigermoth biplane. Tigermoth World is nearby and for my 40th Virginia and I went for aerobatic joy flights...great fun.
I already had enough practice hot wire cut wings laying around for the build so I decided to have a go. I gathered scale measurements from tiger moth photos and made the adjustments needed for a 1.2m wingspan model.
The fuselage is 6mm depron covered with yellow packing tape to mimic the plane I flew in. I added 3mm ply under the nose to take landing impacts and a 5mm ply motor mounting firewall.
The motor is a Hextronic DT750 which had plenty of thrust, especially with a 4S battery. Prop is 11 x 5.5", ESC 40A Plush. 3000 mAH 3S or 4S Lipo gives 20+ minutes of cruising.
Here are build and flight videos of this great looking vintage biplane. It flies just like the real thing, slow and steady with just enough aerobatic capability.
My much loved Versus DLG has been crashed and repaired many times and is looking a bit rough now. But it was a great intro to DLGs. Hobby King's big sale came along at just the right time. The updated Versus, now called the V2, dropped from A$450 to $280, couldn't resist that price.
The V2 has a disser construction wing, crossed CF ribbon reinforcing, and a kevlar pod but otherwise is identical to the Versus.
I bought the Plug N Fly version which is OK, but might have been wiser to get the ARF version and add my own servos.
Here are my detailed build videos showing strengthening and control mods.
After a few weeks the V2 is going well, feels like a better Versus. I wouldn't pay full price for it because there are many better alternatives available, but for the sale price it is excellent.
Ages ago I came across this article by John Gallagher on wax paper bagging DLG tail surfaces, and ever since I have wanted to give it a go.
I'm working on a Fusion style pod and boom sloper designed by Leadfeather on RCGroups and thought bagged balsa tails would suit. My foam elevator is proving to be a bit delicate for repeated rough landings.
2.5mm x 75mm balsa sheet. Elevator will be 100mm wide so an extra strip needs to be glued on.
I'd probably use thinner balsa for DLG tails or sand down the 2.5mm.
Later I realised 100mm wide balsa is also sold at Bunnings.
I need to share my experiences with these DT750 motors. They are well suited to tricopters but do have some design faults which need to be dealt with first.
ESC wire support
The 3 wires are not flexible, just continuations of the single core windings, and will break with bending and vibrations. To prevent this they must be supported around the base with big blob of epoxy glue. I used 5min Araldite and it worked well.
Motor shaft "pull-up" The shaft is about 40mm x 4mm and threaded. In theory you don't need a vibration inducing prop adapter, just a nyloc nut. BUT unfortunately the shaft is not rigidly fixed to the motor bell. Tightening the nut enough to stop the prop slipping pulls the shaft up through the motor bell. This increases the bearing friction making the motor heat up and draw more current. The shaft is only held in the bell by one tiny grub screw, which is not enough to resist the "pull-up" from the prop nut.
I had some nasty crashes caused by a slipping tail prop because I couldn't tighten it down enough. Broke an arm and ruined an expensive digital servo.
The solution is to put a nut onto the shaft right down to the unthreaded part, then a washer, prop, washer and nyloc nut. That way the prop doesn't push down on the motor bell. Unfortunately I had already cut the shaft too short before I discovered this problem so have had to resort to bulky 4mm prop adapters.
Quest for the best propeller Turnigy Slow Fly 10x4.5 props are OK but very thin and flexible.
10x5 Gemfan Carbon nylon Graupner copies from Banggood are much stiffer but less efficient giving shorter flight times.
Emax 10x4.5 props from Banggood are a bit stiffer than the Turnigys and may be the perfect choice. Testing continues.
Here's a quick and dirty tricopter build mostly using materials from my local hardware store.
It covers the basics of design and assembly. The tri flies OK but performance would be improved with more balanced motors and prop adapters and some P and I adjustments.
I haven't covered KK2 setup and tilt mechanism construction but David Windestal's has...
Thanks to great build videos by David Windestal I have recently become interested in tricopters.
Until now I have not bothered with multi rotors at all and still prefer wings and airfoils to motors. But it looked easy enough and searching through my spares box found most of the required electronics. I had three 2822 1450kV motors and three 25A Plush ESCs so only needed to buy a flight control board and some counter rotating props.
Why a tri and not a quad?
Well every man and his dog has a quad which makes tricopters cooler.
Tricopters have a tilting tail rotor for steering, which gives more "plane-like" flight characteristics. Also there are only 3 motors / ESCs rather than 4 so they are cheaper.
KK2 flight control board
The brains of a multi rotor is the flight control board. I chose the simplest board, the KK2 (A$26 from Hobby King).
The KK2 takes your Aileron, Elevator, Throttle and Rudder commands (or stick movements) and translates them into motor speed changes and tilt servo movements.
The KK2 has 2 flight modes: Manual, where the tri will stay at the flight angle you command until you make a correction. Self-level, where the tri will return to level when the sticks are centred. The KK2 also supports the Super Simple Gimbal which is really simple and really works, kind of like steady-cam for an onboard camera.
KK2, Rx and servo power supplies
KK2 board on a tricopter requires two power connections, one to power the board and the receiver, and the other to power the tail servo. They need to be separate for it all to work smoothly. Something about gyros and servos and power loops can cause jittering and instability apparently.
The ESC from motor 1 (front left) plugs into the M1 pins on the KK2 (top right) and provides 5V to power the board and receiver. Do not be tempted to plug 12V in anywhere or you will have to order a new KK2 board (yes I did). There are battery monitoring pins but make sure you know what you are doing before connecting, or just dont use them.
On tricopters a second BEC must be connected to M2 pins (or M3...M8) to provide 5V to the servo. You can use the built-in BEC from the ESC on motor 2 if it is rated high enough. Otherwise add an external BEC.
More than one "switching" style BECs should not be connected on these pins at the same time. Linear BECs are OK. If the ESCs on both motor 2 and 3 have switching BECs remove the red servo wire from one of them to disconnect it's BEC.
On a Quad you can use one normal ESC connected to M1 and three OPTO ESCs because there are no servos needing power. OPTO ESCs do not have an onboard BEC.
Firmware upgrades
There is a lot of chat on RCgroups about which firmware is best for the KK2 and the ESCs on a multi rotor. Apparently Stevis for the KK2 gives more options and better performance than the stock firmware, and SimonK firmware for the ESCs gives smoother and more responsive performance. To start off I used the stock firmware on everything just to get a feel for flying multi rotors, and it all worked perfectly well.
I have since flashed the KK2 with Steveis V1.9 using a $5 USBasp programmer from ebay, and bought Afro ESCs pre flashed with SimonK. Performance is smoother and more responsive.
Here are some early videos. I'll add a build video and onboard footage soon.
At the moment I'm spending time learning to fly better and optimising the tricopter to reduce vibrations. Stay tuned.
Testing and maiden flights
Arm repair time-lapse
SPECS
Motors - Turnigy 2822/14 1450kV
ESCs - Turnigy Plush 25A (stock firmware) x 3
Updated to Afro 30A (simonK firmware) One with BEC to power the board and 2 OPTO (no BEC) plus a Plush 18A ESC (which has a linear BEC) just to power the servos
FC board - KK2.1.5 stock firmware Updated to steveis V1.9 firmware Props - weak flexy green 8 x 4.5" Hobby King / Gemfan Updated to much stiffer Gemfan 8045C carbon nylon CW/CCW pairs from Banggood
Armin wing construction with 6 x 1mm CF strip spar.
The Volantex Ranger 757-4 eventually flew OK but I was getting bored with it.
I decided to change the pusher into a tractor and make it as close to the Tundra STOL plane as possible, and thus the Vundra was born.
Wingspan - 775mm
To increase the stiffness I shortened the tail boom by 150mm, cut 20cm off the 1.5m wing and 30mm off each tail section.
This design was inspired by a friend who wanted to take one of my "retired" planes to learn how to fly. So I gathered bits and pieces together and tried to come up with an easy to fly, crash proof trainer.
The nose is soft packing foam covered with tape and completely encases the 1300mAh Lipo battery.
After some tough flight testing by my dedicated student test pilot it became apparent that this tail
I have never been much interested in scale model planes apart from the Tigermoth biplane. Tigermoth World is nearby and for my 40th Virginia and I went for aerobatic joy flights...great fun.
The shaft is about 40mm x 4mm and threaded. In theory you don't need a vibration inducing prop adapter, just a nyloc nut. BUT unfortunately the shaft is not rigidly fixed to the motor bell. Tightening the nut enough to stop the prop slipping pulls the shaft up through the motor bell. This increases the bearing friction making the motor heat up and draw more current. The shaft is only held in the bell by one tiny grub screw, which is not enough to resist the "pull-up" from the prop nut.
Turnigy Slow Fly 10x4.5 props are OK but very thin and flexible.
Well every man and his dog has a quad which makes tricopters cooler.
The brains of a multi rotor is the flight control board. I chose the simplest board, the KK2 (A$26 from Hobby King). 