FPV AXN Floater jet - 1290mm

Details

 

About

The "AXN Cloud Fly" is most common glider use by many R/C flyer both beginner level and advance pilot.  Not only it can glide like a typical glider but also out of box is a fast flying airframe which some dealer coined them the term "floater jet".  It share almost same flying characteristic and similar flight hardware as the "Sky Surfer @ HK Bixler" with added high adrenaline speed.  The only obvious physical differences between them is that this plane has slender airframe, narrow fuselage cavity, 1 meter wingspans and slender wing surface area.  Also most striking feature is its more aerodynamic looks, it looks fast while in sitting position.   Its a pusher prop where the motor located in the mid just above the tail boom.  It flies as fast as any park flying R/C jet and able to hover stationary or slop soaring around the high windy cliff side.  Available in kit and ARF at affordable $USD39 (approximate) pricing usually can be bought at hobbyking.com online.  This is the my second R/C plane and most abundant in my collection which i always enjoy gliding around the beaches, air racing with club member and friends or simply enjoy surfing around with the wind during my past time.  The plane can easily launch/take off in any mods from hand launches, grasses, rough soil, sands or tarmac.  Almost 70% of our flying member groups owned or previously owned for quite a long term companion as it serve both fun flying around the park especially when doing multiple formation flying in the air.

However the adaption into FPV world is not well conceived by most FPV pilot.  That is because the airframe limitation to carry serious FPV hardware due to size of the fuselage cavity and the load limit.  For FPV conversion the Cloud Fly only can carry minimal or basic amount of FPV setup to make it worth flying a short distance flight.  I did convert my Cloud Fly into FPV platform which is only well suited for aerial chasing, tandem/formation flying and aerial dog fight with friends.

 

 

Model specification & setup

Airframe type: Glider
Branding/Manufacturer: Aoxing (AXN)
Model name variant: CLOUD FLY
Material build: EPO foam
Wingspan: 1290mm
Length: 860mm
Stock airframe weight: 580gram
Full FPV flying weight: 900~1100gram
Aileron: 2x 9g servo HXT900
Elevator: 1x 9g servo HXT900
Rudder: 1x 9g servo HXT900
ESC: 20~30A
Motor: 2100kv
External BEC: UBEC 5V/5A
Propeller: APC style 5x5
Radio receiver: Turnigy 9x 8ch
Radio receiver antenna: Stock Omni
Battery: 1x 2200mah 3s 35c
Center Gravity: 1/3 from the front leading edge of the wing.

 

 

My DIY FPV specification

Camera: 520 TVL Sony CCD
Secondary camera: None
Camera pan/tilt mechanism: Foxtech mech + 2x 9g HXT900 (180 degree mods)
OSD: Hobby King G-OSDII with GPS
Flight Control board:  None
Video transmitter: Boscam 5.8ghz 200mw
Video antenna: Stock Omni
Battery: Shared with main.

 

Building

The FPV installation and issues are similar to "SKY SURFER" setup as i previously build before.  I'm not going to key in  the same comments repeatedly about this setup you might probably click HERE (SKY SURFER) to check the build and read all about it.  The only differences between them is Cloud Fly have extremely narrow cavity inside the fuselage, almost barely able to fit in 2200mah 3s 25c lipo into the front nose without cutting out the extra foam.  Fitting remaining components such as OSD/GPS and Radio receiver is also very tricky because the only remaining cavity access to place this parts are blocked by two rudder and elevator servo at the entrance.  Caution during the build is that this airframe is actually very sensitive to weight placement.  Best keep full flying weight is max 1.1kg.  More than that it will never hover very well and the stall speed tolerance will diminished into uncontrollable "Spiral of Death" problem.   Most ESC and BEC are located inside the fuselage, you'll need to poke bunch of hole on the black canopy cover to let the cool air in to cool them down.  Based on my flight experience Cloud Fly have the highest percentage possibility of "Brown-Out" situation where BEC module doesn't have adequate amount of cooling because the heat is trapped inside its narrow fuselage.

FPV building level difficulty/rating: Medium (8/10)
FPV equipment setup grade: Intermediate
Building hours required: 11 hours
Skill required: Soldering/Foam cutting
Critical issues during installation: Video antenna/RF placement + narrow fuselage
Required additional mods/must do improvement: Reinforce/beef up motor mounting else fail after few round of full throttle + replace weak magnet canopy enclosure.

 

 

FPV flight characteristic and performance

The details below flown and tested using FPV hardware mentioned above. On stock airframe without the FPV equipment the plane flies like a butterfly, however once loaded with FPV equipment its actually tad heavy especially if you are planning to put HD camera such as Go-Pro (i recommend lightweight streamlined 808 #16 V2 HD).  Adding my necessary Pan-tilt camera already off-set much of the axial CG of the plane where i pretty much struggle to keep the plane a float with more effort than before.  I did put a SONY BLOGGIE HD cam along the FPV ride but it turn out to be a disaster flight because its struggle to stay afloat and crash after 4 rounds of flight, it hit "Spiral of Death".  With FPV fully loaded having extra 30% airspeed and keeping less than 35 degree aileron banking is your best friend.   Its is best to fly under heavy wind to get extra lift and i don't recommend this platform for your long distance FPV flight beyond 1.5km because of random twitchyness sign of stalling if your overall flight weight is 1kg.   Here my flight performance review (assume i'm flying in 15km/h wind speed head-on). Given at 150~250m altitude at 45~50% throttle will last a good steady 25 minutes worth of flight time, take note the flight weight value at 1kg.


Minimum level of flight experience required/flight-hours: Beginner(40 hour)
Nature of platform handling experience/skill required: Glider
Self leveling capability in thumbs-off stick situation:  Yes  at 40km/h>>
Take-off & landing difficulty: Medium
Hand launch: Yes
Max speed: 78~km/h
Min speed before stall: 20~35km/h
FPV flight/radius: 1.2km max (given above FPV spec/setup)
Max altitude: -
Bail-out/fail safe recovery altitude limit: 300m
FPV safe distance range for testing: 600~700m (Open field)
High angle of attack (AOA) tolerance limit before stall: 25 degree at 20~25km/h
Ground "STOL" (Short Take Off and Landing) capability/thrust%: None
Altitude climbing power/thrust%/AOA angle: 10 sec/per-meter at 80% thrust/15 degree
360 degree turning radius clearance/holding pattern: 20m
360 barrel roll/loop acro flight: fail (hazard)
Control expo - aileron: 45% (low to high)
Control expo - elevator: 45% (low to high)
Control expo - rudder: 45% (low to high)
Control end point - aileron: 100% (low to high)
Control end point - elevator: 100% (low to high)
Control end point - rudder: 100% (low to high)
Flight time: 25~35 min
Ground spotter visibility (LOS): 500~700m

 

 

Safety issue

Like i said before Cloud Fly airframe is too bottle neck for serious FPV flight because of limited space to install your serious FPV gear and weight to body ratio size.  The wing isn't build to carry load beyond 1kg to carry aerial video/photography quality hardware.  Any weight beyond that will risk of unrecoverable stall "Spiral of Death" problem which 70% more imminent compare to a "SKY SURFER".   After flying almost half a year on this platform i say its best to leave if as normal "Line Of Sight" fun flying than FPV setup unless you going into second path by purchasing micro/nano size camera, 3.3v video transmitter, BEC  and slender lightweight FATSHARK pan/tilt mechanism to save up some weight.  As reference you can watch some youtube video of Cloud Fly, not much people willing to put a Go-Pro on it in contrast to a Sky Surfer/Bixler.   The most ideal way to enjoy this FPV platform is a park size high speed chase and aerial dog fight (without the loops and barrel roll).  Oh speaking of why its isn't ideal for long range FPV flight because the cramp fuselage emits high RF incident that will dwarf your video and radio transmission.

Here a repeated article from SKY SURFER review which applies on this airframe...read on: On ground level zero flight condition where the plane just sit idle around on the table doing nothing where there's no servo servo load or control applied, the servo only consume ranging from between 550mA~750mA peak at almost zero kg-cm for example on HXT900 have temporary 5~10 second torque push at  22.2 oz-in (1.60 kg-cm) when not in the air.  The value of current consumption increase when its airborne and its torque efficiency however is lower since each aileron, rudder and elevator is constantly hammered by wind resistant due to the size of its surface control combine with full control exercise from pilot active radio transmission.  For example servo at 45 degree "flaps" mix mode will probably get hit around ([1.3kg flight weight /2] + 0.9kg wing force) = 1.55kg of load can only hold on just 10 seconds before it had a control lockout due to overheating servo FET chip or if unfortunate burned due to FET "over-amping" which is common on any 9g servo, worse you can "Brown-Out" all flight control.

What's a "Brown-out".  Well it has something do to with your 5V/5A BEC fail to deliver enough current for your flight operation hence "momentarily empty fuel tank" or one of your equipment consume all the available current leaving no surplus of current for other flight control.  Ok lets do some math calculation here about how much current each servo consume, your hardware and etc.  Lets declare some variables below, note that all the value are given at approximate nearest number since in the market there are variable of servo choice and other flight hardware ranging from quality and budget. I'm putting somewhere in the middle:

  1. 9g servo:  750mA (peak control/non-airborne)
  2. Servo quantity required per-platform + FPV pan/tilt camera:  6x unit
  3. Radio receiver operating current:  100mA
  4. Radio receiver operating current:  150mA
  5. External BEC current rating: 5A or 5000mA  (Usually all BEC are commonly 5V/5A)
  6. BEC heat inefficiently current loss: 100mA (Assume worst case scenario of lousy ventilation or quality)


BEC CURRENT SAFE SURPLUS CALCULATION (non-airborne):

"5" - "3" - "4" - ("2"x"1") - "6" = 150mA The amount you have left as backup to power all the control.... you're not even flying yet.

 

Looking at the above value you can conclude why a "Flying Wings" platform are more efficient and less prone to "Brown-out" or control lock-out situation because it uses less servo to control all the flight envelop. "Flying Wings" are for pro pilot you you'd better stick to a glider if you are new and be caution with your build.   5V/5A is the best current supply must have module fo any FPV pilot, however don't rock around to much in the air or doing "active" fancy thing in the air if you knew your current supply is on the verge of jumping off the cliff.

Cloud Fly just like the Sky Surfer being in EPO foam is a plus benefit to the owner for durability and elastic property upon impact but at the same they do pose hazard when crashed to any ground object combined with inertial weight and altitude. Falling at 150m altitude will probably hit average 40-55km/h falling speed on "Brown-Out" control if the 1.1kg weight are located at good CG spot.  I've seen how this plane shatters a car windshield into full debris flown by beginners, its bad news.

If you do encounter a "Brown-out" situation where all your control are jammed after a hard full speed throttle or you rock all your control too much during the flight which most likely cause your BEC to overheat, do the following step to recover your plane and i assume you are at safe "bail-out" altitude.

  1. Release all your thumbs from the stick control and throttle it down to sero.  Don't worry your plane its going to glide on its own.
  2. Wait for a few second say between 3~10 seconds, let the BEC cool down.
  3. **If you are powering your 5V equipment from ESC that have build-in BEC you will need a  slightly longer time to cool down, wait until you hear the audible "initialization/start-up beep" similar beep you hear when you plug-in battery on your plane via your on-board video transmitter's microphone.
  4. Once you feel its the right time to take over the control, pull your elevator and aileron and then start your throttle.  However if your plane is "stalling" point the nose downward to gain extra wind speed  under the wings before  pulling up the elevator.

Brown-out issues is not the only problem you should encounter along your FPV flight, Radio signal loss is very common problem as you wonder too far away from your radio transmitter.  Unlike video signal where you can visually experience degraded video quality on screen as first indication of losing signal range, your non-telemetry standard Radio transmitter doesn't indicate that when you are about to loose  signal, it will occur random time as you exceed 800m distance.  Most advance pilot uses RSSI indicator to indicate percentage lost radio packet before it is completely lockout/disconnected via OSD display but this setup is very costly on your pocket.  Well don't worry i have excellent tips for you.  The first indication that you are about to loose your radio signal is that you will experience "laggyness" or jittery movement on your camera pan/tilt servo mechanism as you move left and right. If it does make a "U" turn back immediately to your home before its too late.

Unlike the though  big brother the "Sky Surfer", The fully loaded FPV gear on Cloud Fly frontal part of the fuselage will shatter into pieces followed with lipo magic smokes on hard soil because its front EPO foam nose part isn't as robust as i thought it was.

 

 

Pros and Cons

Here are list of pros and cons about this platform. Some of this are needed to take seriously if you are going deep into long term FPV ambition

Pros:

  1. You can hand launch anywhere and land on grassy field on belly landing.
  2. Fast airframe, good for chasing around, dog fighting (without loops and barrel roll) and racing.
  3. Cheaper airframe to start and simple mods.
  4. Its a "pusher" propeller driven plane, video recording and pilot viewing is not obstructed by spinning propeller unlike "tractor" type propeller in-front of the nose.

Cons:

  1. Aileron servo will fail after several flight at least a 2 week worth of full  FPV operation. This is because if the airframe that weighted more than 1kg, the aileron is going to be over burden carrying the load plus constant wind turbulence hammering from beneath.  This stress escalates more if both aileron to be used as flaps mixing.
  2. When full loaded with FPV gear over 1kg there's going to be high incident of stalling and "Spiral of Death", spiral recovery is almost impossible.
  3. Despite being strong and robust airframe made from durable EPO foam it actually does causes major damages to ground property as it going momentum speed during a dive. High density compressed EPO foam are heavy unlike EPS foam.  The frontal nose however is not as robust as i thought i would be. Caution to that.
  4. Video signal transmitted on planes best placed when the antenna is LOS (Line Of Sight) with ground receiving antenna but the best place to put on this airframe is at the tail boom where is  blocked by blocks of fuselage and "pusher" motor.  Putting it under neat the fuselage will be squashed during landing.
  5. Super cramp fuselage cavity, RF emission is high inside unless you dangle all the sensitive equipment outside but that destroys the planes aerodynamic efficiency.
  6. Motor mounting wall need to detached and re-glue because out of factory is not guarantee to be fail proof.

 

 

Current status & flight history

As an FPV platform its a bad news and didn't live long enough to survive my FPV ambition, i did have fun flying and chasing around tailgating my buddies plane around our Club field on FPV and it was a blast.  As second FPV plane it didn't have much beautiful FPV HD recording flight nor mature yet to get a good quality FPV gear worth long range fying target.   Most of the recording made on DVR non-HD.  My flying club mostly own AXN Cloud Fly as general platform to do fun "Line Of Sight" (non-FPV) tandem flight, formation flight, beach gliding and slope soaring together, its a great platform to socialized with friends thus which is why back in the days i used to have about 5x unit of Cloud Fly due to extreme fun factor.

 

Lifespan operation: 5 months
Maintenance priority check: Aileron, elevator servo and plastic root flight linkages
Constant critical issue: Aileron and servo servo worn out/jammed due to load stress
Maintenance cost per-lifespan: USD$30 (Servo)
Flight hours accumulated per-lifespan: 96 hours
Best L.O.S distance record: 1.1 km
Est. distance covered per-lifespan: 950km (Odo)
Best height record: -
Best flight time record per-session: 35min (2200mah 3s 35C)
Best low hovering speed record: 12km/h
Best record  for zero thrust landing distance/power failure glide recovery distance: None
Activity status: Retired (mid 2011)
Reason of retirement: Spiral of Death issues and overweight.

 

 

Summary

If you are looking a airframe for normal Line Of Sight flight like gliding around the beaches, slope soaring, circuit racing, tandem flight or fun socializing with friends then this is for you.  Great for beginner, you will grow your flying skill along the way and still very addictive to any veteran/skilled flyer.  However conversion to FPV isn't ideal especially if you are looking towards long range endurance flight or you want to grow with it.  Its a weight sensitive platform, cramp fuselage and does not tolerate something heavy installation above the fuselage such as placing a Go-Pro or any popular heavy duty HD camera especially gimballed.  If you persist into FPV then select a super-light FPV hardware to fit it well and caution to RF issues, keep it below 800gram to avoid "Spiral of Death" stall issue.  If i want to give rating within 10 range i'll give 10/10 for fun LOS socialized flying and 2/10 for FPV.   The last flight i put Quanum telemetry inside the cockpit, the RF kill everything on board after 2 minutes of flight, however it didn't happen inside my SKY SURFER of same hardware setup.  Will i give Cloud Fly as second FPV chances? Nope.

 

 

Videos/Medias
MediasHere are some of my video and gallery related to the above topics:

 

 

 

 

 

 

Shopping list

Here I've listed some raw material, hardware and stuff where you can start building your own FPV platform.  The list contain the above hardware and also include some compatible ones which you can pickup what suits best for your need and your budget.  So come dig around and start your tech flying ambition:

  1. Platform/Airframe:
  2. Radio set/combo:
  3. Motor/ESC/BEC:
  4. Servo:
  5. Camera/HD/DVR:
  6. Flight controller/AP System/OSD:
  7. Video transmitter/combo:
  8. Battery:

 

 

Building threads/Referral

If you don't know where to begin with i recommend you to start reading some guides, wikis and building tips from popular on-line resources as listed below.  You might find me hanging around some popular R/C and FPV forum below.

 

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