SMALL - Telemetry SMALL - Radio
Thread Tools
Old Aug 06, 2014, 08:23 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
Build Log
Free Flight X4 Review from FPVModel

The Free Flight X4 is the newest multirotor platform to be introduced by FPVModel.com. With 800mm detachable arms, this heavy-lift quad is just the ticket for all those space-deprived pilots out there. With the arms removed, it has a footprint slightly smaller than a DJI Phantom. But this is no GoPro hauler; the X4 can easily lift a DSLR camera and gimbal. However, I think the X4 is really going to shine with a mirrorless slr and gimbal payload. With 10,000mAh of 6s power and a weight-friendly Sony NEX-5r, we should see some decent flight times.

Recently, I reported on FPVModel's call for a reviewer to test the Free Flight X4, and I threw in my hat for a chance to test it as an RCGroups editor. I was chosen along with another member to evaluate and review it. Instead of the standard review, I'm posting this as a thread and a work in progress. We'll touch on what's included, getting the X4 ready for flight, flight performance, and everything else along the way.

The kit
The Free Flight X4 comes completely built and ready for your flight controller and receiver. In fact, the only tasks you're faced with are bolting on the landing legs and installing the propellers.



Here's a list of what's included with the frame:
  • 4x 15x5.5 carbon fiber props
  • 4x 4114 400kv brushless motors
  • 4x 40amp esc's
  • Electric retract landing gear
  • Power distribution board

The majority of the frame is carbon fiber while the bottom frame plate is a printed circuit board (pcb). Between the frames, the power distribution board takes power from the battery lead (fitted with an XT60 connector) and sends it to each arm's bullet connectors for the esc's. On the bottom of the frame are a pair of XT60 connectors integrated into the board. These can power the gimbal, lights, or any payload you have slung under the X4. Just remember that the XT60s on the bottom output whatever your main battery voltage is; use a stepdown regulator if needed. The overall fit and finish is very good, I didn't see any burrs, damage, or errors from the factory. One area that definitely needs attention is the lack of thread locking compound on the fasteners. Take your time and go through the entire kit, remove each bolt and apply thread locker. I found all eight of the arm-locking levers to have lose grub screws... losing one of the levers in flight wouldn't necessarily mean losing an arm, but it would make removing the arm a bit difficult.



The gimbal and camera
For a payload, I chose the only gimbal I had on hand that would work with this airframe, the ACK Pro. Unfortunately, it's only a 2-axis, which makes retracting the landing gear an effort in futility. But for testing purposes it will do just fine. The gimbal was designed for a mirrorless slr, so the Sony Nex-5r will be used. The gimbal plate on the bottom of the Free Flight X4 has a number of pre-drilled holes, but none lined up with my Hobbyking gimbal's mounting plate. A few minutes with the drill, and I had the gimbal mounted on 1" aluminum standoffs and ready to stabilize.



Flight controller and batteries
I decided to run the DJI Naza V1 w/ GPS. This specific unit has seen a number of airframes and always performed as expected. On the front and back of the top frame plate are a pair of holes that align with the DJI GPS mount, so that's where the GPS found it's home. FPVModel calls for 6s batteries, from 10,000mAh to 20,000mAh on the X4. I have many pairs of 6s 5000mAh and a few pairs of 6s 10,000mAh packs, so I decided to start with the smallest ones and see how they perform. Note that five male to male servo wires will be needed; four from the flight controller to the pcb, and one from the receiver to the landing gear actuator.



Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Last edited by Matt Gunn; Aug 07, 2014 at 07:15 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 06, 2014, 08:25 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
Tomorrow I will do the maiden flight, adjust PID's, and begin to dial her in.

Stay tuned!
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Old Aug 07, 2014, 01:45 AM
schumixmd is offline
Find More Posts by schumixmd
schumixmd's Avatar
Moldova
Joined Jun 2010
2,059 Posts
Nice Matt.
waiting for the maiden.
schumixmd is offline Find More Posts by schumixmd
Reply With Quote
Old Aug 07, 2014, 12:07 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
I just got back from the initial test flights. A good uneventful session; the flights were for tuning and gauging battery performance only. I'm using two tired pairs of 6s 5000mAh Turnigy packs rated at 20c. They are a few years old and have had many cycles, but the internal resistance on each is more than acceptable at 13mΩ and 22mΩ. On both flights, with a mix of hovering and forward flight, I got around 11.5 minutes before my low-voltage alarm started flashing on the Naza. The packs has roughly 30% left after landing.

I got the roll and tilt gains adjusted well, but the yaw and altitude are not quite there yet. I kept increasing by 10 and slowly started reeling in the vertical and yaw drift, but decided to come back to the "lab" and recharge. I'll head back out later to get those two parameters dialed in better. In its current setup, it has plenty of "punch out" power to climb quickly.

The landing gear open and close at a good speed with no noticeable change in altitude when they activate. I'll get some video of the X4 in action soon.

Not related to the actual performance of the quad, I have a bit of PID adjustments needed on the gimbal controller. A few times, the camera roll fell off due to the downwash from the props. An increase in motor power should solve that.
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Old Aug 07, 2014, 08:20 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
After another flight today, I made a mind bending discovery: New batteries work much better than tired old batteries. Imagine that!

I decided to run a brand new Pulse 6s 10,000mAh pack by placing it sideways across the battery plates and strapping it down. My flight time went from 11.5 minutes on the pair of 6s 5000mAh to a very respectable 15.5 minutes. This was a mix of hovering, full speed flight, and multiple fast climbs.

I think I have the gains set on the Naza, but I'll do a bit more tuning tomorrow just to squeeze every bit of stability out of the flight controller. The gimbal controller holds a lot better, but I'm getting a bit of shaking as the prop wash beats the gimbal around. I replaced the soft rubber isolation dampers with hard rubber, but it's still not enough to keep it from shaking left and right slightly.

I'm very impressed in the balance of the blades and motors; while the X4 was in a gps hover, I did the old touch test (yea, stupid and not something I recommend) and not a vibration could be felt in the gimbal.
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Old Aug 08, 2014, 10:38 AM
BenHayat is offline
Find More Posts by BenHayat
Always Excel >>>
BenHayat's Avatar
United States
Joined Mar 2012
2,334 Posts
Thanks Matt;

Personally, I think this craft was designed from start to also run in X8 configuration to provide more safety, redundancy and stability.
If you get about 15 minutes in X4 with the new 6S 10,000 battery, what do you think an X8 would result in time wise?

Would you say with 2 10's we might get 10 -12 minutes with same camera arrangements? (considering the extra battery weight, motor weight, ESC, Wires and power consumption).

p.s. I love the design of those arms.
BenHayat is offline Find More Posts by BenHayat
Last edited by BenHayat; Aug 08, 2014 at 10:47 AM.
Reply With Quote
Old Aug 08, 2014, 10:43 AM
BenHayat is offline
Find More Posts by BenHayat
Always Excel >>>
BenHayat's Avatar
United States
Joined Mar 2012
2,334 Posts
What would be the best FC for this craft (in X8)?
Naza, A2, SuperX or ZeroTech?
BenHayat is offline Find More Posts by BenHayat
Reply With Quote
Old Aug 08, 2014, 12:05 PM
monkeyking is offline
Find More Posts by monkeyking
Registered User
Joined Jun 2006
55 Posts
I believe that most of us want to see it in X8 config with 18inch props to improve performance and lift capacity.
It is probable that is you are interested in a 800mm quad you will want to use it as heavy lifter and with redundant configuration to carry an expensive camera and gimbal.

What the other users think??
Add a "+1" if you agree
monkeyking is offline Find More Posts by monkeyking
Reply With Quote
Old Aug 08, 2014, 12:35 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
I could be wrong, but I don't think this is the ideal platform for a big DSLR and 3 axis gimbal. The weight of the payload and additional batteries would hit the point of diminishing returns IMO. I have a GD X8 1000mm with Phoenix A10 gimbal and haul up a canon DSLR. It needed a pair of the 6s 10,000mAh packs just to get 10 minutes of flight time. The weight of the gimbal, camera, and flight batteries is 13 lbs. The X4 has an advertised max takeoff weight of 17.6 lbs. With the 8 lb weight of the X4 without payload and batteries, we've now exceeded it's max weight by 3.5 lbs.

I think the slightly more weight-friendly mirrorless slr and gimbal allow the use of a single 6s 10,000 (or a pair of 6s 5000) is where this frame and electronics combo finds it's sweet spot. Now, add in 4 more of these Free Flight 4114 400kv motors with the 15x5 props, and it will really shine with stability and longer endurance flights.
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Last edited by Matt Gunn; Aug 08, 2014 at 01:49 PM.
Reply With Quote
Old Aug 08, 2014, 01:09 PM
BenHayat is offline
Find More Posts by BenHayat
Always Excel >>>
BenHayat's Avatar
United States
Joined Mar 2012
2,334 Posts
Quote:
Originally Posted by Matt Gunn View Post
I could be wrong, but I don't think this is the ideal platform for a big DSLR and 3 axis gimbal. The weight of the payload and additional batteries would hit the point of diminishing returns IMO. I have a GD X8 1000mm with Phoenix A10 gimbal and haul up a canon DSLR. It needed a pair of the 6s 10,000mAh packs just to get 10 minutes of flight time. The weight of the gimbal, camera, and flight batteries is 13 lbs. The X4 has an advertised max takeoff weight of 17.6 lbs. With the 8 lb weight of the X4 without gear, we've now exceeded it's max lifting capacity by 3.5 lbs.

I think the slightly more weight-friendly mirrorless slr and gimbal allow the use of a single 6s 10,000 (or a pair of 6s 5000) is where this frame and electronics combo finds it's sweet spot. Now, add in 4 more of these Free Flight 4114 400kv motors with the 15x5 props, and it will really shine with stability and longer endurance flights.
So, you do agree an X8 configuration is ideal?
BenHayat is offline Find More Posts by BenHayat
Reply With Quote
Old Aug 08, 2014, 01:45 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
I would venture to say that given the added weight of only 4 more motors, props, and esc's to this frame, you'd see a nice increase in flight time over the current 15 minutes I'm getting now. I'd guess easily over 20 minutes with 6s 10,000mAh and a similar gimbal/camera payload. Plus, you cant beat the system redundancy and stability in windy conditions of an X8.
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Old Aug 08, 2014, 02:01 PM
BenHayat is offline
Find More Posts by BenHayat
Always Excel >>>
BenHayat's Avatar
United States
Joined Mar 2012
2,334 Posts
Quote:
Originally Posted by Matt Gunn View Post
I would venture to say that given the added weight of only 4 more motors, props, and esc's to this frame, you'd see a nice increase in flight time over the current 15 minutes I'm getting now. I'd guess easily over 20 minutes with 6s 10,000mAh and a similar gimbal/camera payload. Plus, you cant beat the system redundancy and stability in windy conditions of an X8.
I think an X8, with Sony RX100 + Gimbal and a 6S 10K or 15K will be a great setup.

On my other question, what FC would you see fit well for an X8? Honestly, I take this over an S900. The build quality is much more superior.
BenHayat is offline Find More Posts by BenHayat
Reply With Quote
Old Aug 08, 2014, 05:49 PM
BenHayat is offline
Find More Posts by BenHayat
Always Excel >>>
BenHayat's Avatar
United States
Joined Mar 2012
2,334 Posts
Where are the ESCs placed? And is that where the extra 4 would go?
BenHayat is offline Find More Posts by BenHayat
Reply With Quote
Old Aug 08, 2014, 07:33 PM
Matt Gunn is online now
Find More Posts by Matt Gunn
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,801 Posts
They are in the arms. That's where another 4 will fit.
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Old Aug 09, 2014, 07:55 AM
lasicm is offline
Find More Posts by lasicm
Registered User
United States, NV, Las Vegas
Joined Apr 2014
101 Posts
What would someone expect to pay for a set-up like this?
Including the gimbal, less the camera.
Thanks.
lasicm is offline Find More Posts by lasicm
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Cool Free Flight X4/X8 from FPVMODEL.COM fpvmodels Multirotor Talk 132 Aug 31, 2015 10:52 AM
Discussion VIDEO: Hubsan X4 v2Quadcopter Review & Flight Demonstration makuloco2000 Micro Helis 0 Sep 15, 2013 10:11 PM
Mini-HowTo HUBSAN x4 Pre-flight Mod Video and mini-review Budasac Mini Multirotors 16 Jul 17, 2013 10:14 PM