|Apr 06, 2014, 03:16 PM|
The Ranger EX Long Range FPV Platform thread - full review and build log
This is a review and build log of the Ranger EX Long Range FPV Platform by VolantexRC.
The full review, as well as a detailed parts list can be found in my blog: ArxangelRC.blogspot.com
Here is a link to the Instruction Manual, in case anyone is interested: Manual
Some time ago I was looking around for a good FPV plane, and I came across the FPVraptor. I fell in love with its plastic fuselage - all that durability and internal space makes working on the plane so much easier, and keeps repairs to a minimum. Soon after that I found that there was a V2, and I was also told that VolantexRC were developing the Ranger, so I contacted them. The Ranger offered even more internal space, the same durable plastic fuselage, larger wings (more carrying capacity), and lots of places where you can place a camera. The cooling openings at the front were also a nice touch, since that meant I can put some serious electronics inside, without having to manually modify and drill the fuselage to get some cooling. As it happened, I was one of the few lucky people that got their Ranger EX just before it was ready for distribution, so here is my review of the KIT version.
I chose to get the KIT version, because I think most people would also opt in for it. I have nothing against PNP versions, except the stock electronics. This is a large and serious platform that many people are going to strap expensive equipment to, so I wouldn't expect them to keep the stock gear anyway as the general reliability of the gear is mediocre at best!!
Wing span: 1980mm
Flying weight: ~1500 grams w/o battery (actual achieved - 1995 grams w/o battery for the current configuration, 2899 grams with the flight packs)
CG: about 62mm from LE (confirmed)
The whole shipment from Volantex arrived via DHL in 3 days. The planes were packed in a bigger carton. There was no external damage to the packaging and boxes, but the Ranger did have an issue with the main wings, but nothing serious.
Both parts of the wings had slight warping on the parts of the flaps near the fuselage, I guess that was due to mishandling in the factory, because the box was not damaged. The warps were quickly straightened by hand alone.
The flaps do have to be cut out to be used, so I guess when the wings were damaged, the warping also cut some of the EPO that holds the flaps. Since I am not planing on using the flaps at this point, I taped the cut with fibre tape, and hope this will be enough to hold it in place.
Apart from the above, the plane was well packed and everything else was in pristine condition.
WHAT I LIKE
There is so much I like about this plane, that I am not really certain where to start!!! So lets start with the obvious - this model has A LOT of internal space, and the fuselage is made out of durable plastic. In my eyes these are the most valuable features of this plane.
And just to get an idea of how much space there is inside, take a look at this - 4x 4S 20C 5000mAh Flightmax li-pos put side by side in the nose of the plane!!!
For now, however, I will be flying with only 2x 4S 20C 5000mAh Flightmax li-pos at first, but wired in series for an 8S 5000mAh set up.
Next on my personal list of nice features are the cooling inlet openings at the front of the plane, as well as the many camera mounting options, and the flat fuselage bottom, allowing a camera gimbal to be installed.
The nose of the fuselage features an integrated camera mount, with an opening only for the camera lens. The lens opening is sealed, but IF it is going to be used, it could be cut open.
The plywood battery plate extends back into the fuselage, where it sits on a piece of EPO foam, which in turn rests on the bottom of the fuselage. This provides a nice solid, flat area to mount and autopilot system on.
The bottom of the fuselage has a hole that acts as an outlet for the cooling inlets. I am yet unsure how those cooling inlets will affect the autopilot's barometric sensor, but I guess I will find out soon.
Of course, mounting a gimbal underneath the plane would not be possible without the massive aluminium landing gear.
Another VERY nice feature is the fact that putting this plane together requires only a screw driver, a long and thin one preferably, and absolutely NO glue. This means that the plane could be easily disassembled and put back in its original box, or for transporting.
The wings and the landing gear are mounted via metal bolts that screw into blind nuts in the fuselage. In my book this very good for reliability, although it could be a problem during a crash, since the bolts could rip a hole, or two, in the fuselage.
Being an APM user myself, the bubble lever on top of the wings is a VERY important feature. When powered up, the APM benefits from being as levelled as possible white it is initiating. Having that bubble lever there removes the guesswork from levelling the plane at the flying field.
The plane also comes with a lot of hardware, servo extensions, screws, bolts, and 6 velcro straps. There are even a lot of spare screws and bolts, which is not what you'd expect with most KITs.
Having pre-installed spars is always a good thing, saves quite a lot of time when it comes to putting the plane together.
Finally, I would also like to comment on the plane's instruction manual. Even though most people will not need it to put this plane together, I was pleasantly surprised that the build instructions actually made sense, and could be useful if someone decides to take a look.
The video Tx plate behind the prop is a nice touch - it provides a convenient place to mount the video Tx, as well as moves more weight to the back of the plane, so that more equipment can be installed in the nose. However, mounting the video Tx there would only work for short range FPV flying. When flying long range, on the way back all of the electronics and batteries will be sitting behind the video Tx and the ground station, which would seriously degrade signal strength, so mounting it on the wing might be a better option.
WHAT I DON'T LIKE
As usual, no plane is perfect, so here is what I don't particularly like about this model. First and foremost, that would be the main spar. On the Raptor, the spar has a much thicker wall, and is MUCH stiffer. This one bends quite easily, and its walls are not that impressive, although I guess that can be quickly remedied by gluing a second carbon rod on the inside, but it does require additional expenses, as well the sparing the time to go out and find the right size carbon rod.
The locking mechanism of the canopy does not actually lock as it is supposed to, but I guess that is not an issue because the canopy itself is very hard to press into the fuselage, so I don't see it coming off mid-flight any time soon.
Also, the way the black canopy cover snaps onto the canopy is very weird, and will certainly NOT hold the cover on for too long after take off. It sits very loose, and I can remove it by just knocking it with my hand, it will surely fly away quickly when air gets underneath it.
The motor angle is another concern about this model. Just like the first Raptor, the motor is pointing straight back on the Ranger as well. The test flight proved my suspicions that at full throttle it will push the plane's nose down, BUT since this model is mean to be used with a landing gear, and will rarely be flown at full throttle in the air, this is not a problem when the plane is flown at cruise speed. The motor's angle is an issue when the plane is to be thrown by hand, which is not how this model was designed to be used. At some point I might print out an angled up motor, so as to adjust the motor's angle AND be able to install a larger prop.
One thing that I noticed during the maiden flight was that the wing flexed a good amount, especially when the wind was blowing. I will have to see if reinforcing the spar could have a positive effect on this, but in any case I know that the wing could use some more stiffening, especially towards the tips.
When I consider that the motor's angle is not a problem when taking off with the landing gear, all the other issues are not really that big. Overall this model is amazing and it is obvious that a lot of thought had been put into designing this with FPV in mind.
The plastic used for the fuselage makes the plane very durable (I know that from my experience with the FPVraptor), which also ensures its longevity. The absolutely HUGE internal space is almost unreal, and it provides for easy installation of all electronics and a lot of batteries. One would be hard pressed to fill out all that space.
The landing gear is aluminium and very tough, but flexible in order to take the load of the plane on rough terrain. The big tires also help with taking off and landing on grass and other rough terrain.
At almost 3kgs the plane felt very light in the air, it was able to glide for ages. I had to make a couple of passes during landings because it would not come down against the wind, even with the motor off. I am certain the plane could take more weight without an issue, but that will be a test for a later stage of this project.
Right now I can say this - this really is one well designed FPV platform with a durable fuselage and TONS of space for all the equipment you can imagine. Putting it together is quite easy and quick, and not having to glue anything means that it can be easily taken apart for storage or transportation. The modular design of the motor mount means that there could be a properly angled one in the near future, which would allow for a larger prop. The multiple camera mounting options put this plane in a class of its own and provide the versatility that many people now need. I would definitely recommend this plane for anyone looking for a good FPV platform. I know I love it, and I have a lot of testing and experimenting to do, to see just what it is really capable of.
THE BUILD, AND MODIFICATIONS
So, lets get this show going already.
This plane is a good deal bigger than the FPVraptor, and yet the box it came in is not much bigger than the Raptor's. It is slightly longer... (Yes, I will be writing up reviews for the Firstar and the Raptor V2 soon)
... and slightly wider. I do love the graphics on the boxes though. These definitely do not look like some cheap boxes, which is definitely a testament to the planes inside. I almost feel like I don't want to throw the boxes away, but I've got no place to store them sadly.
First on the build to-do list is the tail. All parts came free from defects, warps, damage, etc. I love the Volantex tail assembly, using only screws and no glue. All control surfaces on the plane feature foam hinges, but they appear to be strong enough to take any load as long as the plane does not crash, so I will be using them rather than installing plastic hinges for now.
Unlike the Raptor, the mounting bracket is glued to the Ranger's vertical stab, rather than screwed on. That definitely speeds up the assembly, but I just pray the glue they used is better than average and that enough of it was used.
The rudder control horn is part of a whole bracket that is also glued on. The control horn has a small reinforcing piece, which makes it very stiff, I like it. The bottom of the bracket has a clamp for the tail wheel of the plane. I really like this solution, but we will see how it holds up long term.
The tail wheel comes pre-installed into its holding arm, which from the looks of it, saves a lot of assembly time for the end user.
Once the tail wheel assembly is mounted on the tail, the horizontal stabilizer just slides on it. The vertical stabilizer goes on top of the horizontal, and when the tail assembly and the vertical stabilizer are screwed together, everything is held together quite solidly.
The elevator plastic reinforcing bracket looks very solid, it is also glued on. Unlike the rudder, the elevator has pre-drilled holes for a control horn, but I think a better option would have been integrating a control horn in the bracket, like on the rudder.
Continues in next post...
|Apr 06, 2014, 03:18 PM|
...continued from previous post.
Inserting the tail wheel assembly into the holes in the tail does require some effort, so don't be alarmed if it is hard to do. I had to push and squeeze a lot to get it in all the way.
While inserting the wheel assembly, you might want to squeeze the tail from the sides, to prevent it from compressing, that way it will be easier to push the assembly all the way though.
Next in were the rudder and elevator servos. I used the provided servo extension cables, and used my own servo extension locks to make sure the extensions stay on at all times. I am using the Corona CS-929MG servos, same as the ones on the FPVraptor. These are analogue metal gear servos that have proven their worth over and over again. All servos on the Raptor have survived a lot of crashes, and being analogue means that their consumption is lower, which is very important during those long range/duration FPV flights.
In my mind, putting the tail servos at the back of the plane, means that you can put even more weight at the front, which is where the valuable load goes with these FPV platforms. The screws for mounting the servo are provided with the KIT.
When it came to installing the control horns I used my own control horns rather than the ones provided with the KIT. The KIT horns felt a bit soft, so I thought I'd go with what I know I can trust. I did have to enlarge the holes on the new ones in order for the clevises to fit.
Now that I've installed the servos and control horn, it is time to mount the horizontal and vertical stabilizers. The horizontal stabilizer goes first, and slides on to the screw rods sticking out of the tail.
The horizontal stabilizer goes on top, its screw rods go into the openings of the horizontal stabilizer, and meet with the rods of the wheel assembly.
At this point the tail wheel's control arm should be pushed into the bracket on the rudder to allow control of the wheel.
Next step would be to screw the wheel assembly to the tail and to the vertical stabilizer. This is where you would need that long and thin screw driver, because the screw rods are quite deep.
Next I installed the push rods.
The kit came with little bands to keep the clevises from opening mid-flight. That is always a sign of some good though process over at the factory.
Now that the tail was sorted, I moved on to the front landing gear. Like I said, it is very well made, and seems very sturdy. It bolts on to the fuselage via bolts and blind nuts inside, which makes the mounting very secure and very unlikely that it will be ripped off during normal exploitation.
When installing the wheels, unscrew the inside nut a little, so as to get the landing gear brace away from the tires, then tighten the lock nuts very well.
This certainly is one tall landing gear.
Before we move on with the build, I would like to share a little surprise that I found in the box - a dome!! A clear and smooth dome that looks amazing.
This dome was not present in the "Box content" photo in the manual, so I guess they added it to the kit after they made the photos.
There is a hint of a dome on this graphic though, its the third icon from the top. This dome could be very useful for certain applications.
And now back to the build. Next is the motor and motor mount. The motor mount is quite cleverly designed, and as long as the motor's mounting holes are with the right spacing, you can mount as big a motor as you like. The mounting plate itself even has a slight right angle to it, which is a nice touch. All necessary mounting screws and bolts are included with the KIT, including mounting bolts for the motor.
The motor mount... mounts to the top of the fuselage, and when you put it there it sort of snaps into place. This is good because it means that when the motor is running, the load of keeping the mount in place does not fall solely on the screws, but also on the snap points, which makes the whole thing much more reliable.
There is a small opening for the motor wires just under the mount.
I had prepared two motors for this model - the Tiger Motor MN4012-9 480Kv and the MN4120-8 465Kv. My original idea was to use the 4120 on 10S with a 10" prop, and I still might give this configuration a try, but for this first test I decided to go with the 4012 on 8S with a 10x7SF prop. Of course, the ideal set up will be with the 4120 on 8S spinning a 12" prop, but that would require an angled up motor mount, which means that it is off of the table for now.
I have to say, these big Tiger Motors came with a lot of accessories!! They cost a lot, but you sure get a lot of bang for your buck!! This has to be most massive and impressive prop adapter that I've seen.
The stock motor wires were far too long for this application, so my first task was to shorten them down.
Then I mounted the motor to the motor plane using the bolts that came with the plane.
So as not to mistake the orientation of the motor plane, there is a small "tooth" sticking out from one of the sides, which corresponds to the appropriate hole into one of the halves of the motor mount.
The motor mount screws together with 3 screws.
Four screws are used to mount the motor mount to the fuselage, two on each side.
The stock prop is 10x5, but it was never my plan to use it.
I think the APC 10x7SF prop would work much more efficiently at low RPM, looks much better, and is much more reliable. I had to use two washers for the prop, one on top and one on the bottom, because the prop adapter's base is too wide, and the prop did not lie flush on it.
The motor mount is pointing pretty much straight back, if there is any up angle, it is very small. There is a descent amount of space between the fuselage and a 10" prop, but I tested with an 11" prop, and it was touching the fuselage, so it would not be usable for the time being.
Next was the ESC. Since I will be going with 8S and/or 10S set ups, I got the K-Force 70A HV OPTO ESC (re-branded HobbyWing), because I've used K-Force ESCs on other projects, and I am very happy with their reliability. And a word of CAUTION - when using the above motor with this ESC, make sure you DO NOT set the ESC to 24KHz!! This resulted in some pretty aggressive motor stuttering above 30-40% throttle, and it went away only after setting the ESC back to 12KHz.
I soldered 4mm connectors all around, not because I will be putting that much current through them, but just in case I decide to use these components somewhere else, where I will need to put 70A through them. I chose a random spot in the fuselage to mount the ESC. Used self-adhesive velcro to mount it.
Now it came time to install the video Tx. Since the maiden flight would be a very close range flight, I mounted the video Tx on its plane on the tail, but will move it on the wing when I fully equip this platform.
Since I took this video Tx from the Raptor's wing, it was already equipped with sufficiently long wires to reach the front of the plane.
Continues in next post...
|Apr 06, 2014, 03:20 PM|
...continued from previous post.
I then installed the FPV system battery and the UBEC supplying the key chain cam with power. Since a regulator in the video Tx brings input voltage down to 5v anyway, I am using a 2S pack to power it because it doesn't heat up as much, and it is lighter.
For now I am using a 2S 2700mAh li-po to power the receiver and servos only, but later on that battery will be used to power the video system as well. The autopilot system will have its own independent battery. For the test flights I have installed my Graupner radio system with a GR-12 receiver mounted in the plane. 6 channels should be more than enough to run my tests before installing an Rlink receiver.
This UBEC is what powers the receiver and servos.
Now almost everything is installed and ready for the maiden. I decided to install a Graupner voltage sensor, instead of a li-po alarm. The voltage sensor connects to the balance connector of the flight pack, then to the receiver, and I can see the separate cells' voltage, as well as the total voltage on my radio on the ground. The Graupner system is good up to 4-5kms, so it will work well for testing and set up. I've never had a problem with brownouts with the Graupner receivers, but I installed a capacitor just in case. Ignore the mess of wires at the back, this will be sorted when I get to installing the autopilot.
Finally, it is time to install the wing servos, and to put the wing together. I needed to cut very little to fit the Coronas in the wing, since they are 12 gram servos, and the servo nests are generally designed around 9 gram servos. I used the last of the servo extension that came with the plane here, as well as the Y-cable to connect them to the receiver. Even though I covered the wiring with fibre tape, I also put servo extension locks just in case.
Push rod installation was pretty straight forward, I used my own control horns here as well.
This still looks very clean because I've not yet installed the receiver and the video Tx on the wing!! There will be cable chaos once I do that.
Now the spar goes in. The spar is exactly 1m long, and the good thing is that it goes equal lengths into each wing.
Installing the wing joint / bubble leveller plate took some effort, to get it in, as it was a very tight fit, but with some little patience it is quite doable, and once done it will stay in.
When time came to mount the wing on the fuselage, a problem presented itself. The wing mounting bolts were just a little too short and were not able to reach the blind nuts in the fuselage. Problem was that the wing is a little thicker at the back end, the front was a little slimmer, so the bolts at the front were reaching the nuts and could be tightened. Thankfully, I had some longer M4 bolts at home, so I was able to quickly resolve the issue.
Now with the wing securely bolted on, it was time to put the canopy on, and see what this beast of a plane looks like. Of course, like I said at the start of this review, the black canopy cover looks good, but will never stay attached to the plane in flight, so I put it on just for the pics.
This is one LARGE plane!!!
This is what will be mounted at the front of the plane. With everything installed the plane balanced perfectly at 62mm from the LE, as per the manual.
And now it is time for some photos from the flying field, and some flight photos, and the maiden flight video.
I have nothing against the Volantex decals and stickers, but since I've got my own, I'd rather use them instead.
When I look at it from the side, it kind of reminds me of a Chinese dragon!!
I know it looks big and clumsy... but there is something beautiful about this plane... it is SOOOO white!!!
Now it is finally time to do some flying. Taking the plane down to the field.
Final moments before take off...
... and away it goes!!
The plane did require some trimming once in the air, but nothing out of the ordinary. This motor pushed it around with quite the authority, and I am happy to report that the prop did not blow to bits even at full throttle.
There was some wind, and that is when I noticed the wing flex, but the plane still felt a bit light. I am certain that it could take much more loading, which would also result in a much more stable flight. When the wind died down, it looked very good on the low passes, and I was quite surprised at how agile it was, despite its size. I did not feel or see any tip stall tendencies even when slowing down the plane for a landing.
It did look very majestic in the air, I am certain it will make a very nice long range platform, when it is finally properly equipped. Now enjoy some flight pics and the flight video.
The plane is very agile, it was able to pull off some pretty sharp turns without much trouble or struggle.
Nothing is hanging down through the cooling outlet, I guess that is a good indication of my chaotic wiring skills!!
When I bring the throttle down, the plane would glide for ages. If kept light enough, it might be able to even catch some thermals at the right height.
The dragon looks good in the air.
And here is the flight video.
The total duration of the maiden flight was around 30 mins (I landed a couple of times, but did not change the battery). The batteries had lost around 2300mAh from a total ot 5000mAh. Since I am gunning for a two hour flight with this platform, it would seem that it will take some testing before I get there, so stay tuned, this should be interesting. More updates to follow soon.
|Apr 06, 2014, 03:22 PM|
Well... that review certainly took some time!!
I would appreciate any comments, recommendations, critiques, etc. Anyone who wishes to share their Ranger build is welcome to do so in this thread, just so we can keep things in one place.
|Apr 07, 2014, 04:34 AM|
My plane is 3kg right now, so at this final AUW I wouldn't go with anything less than 900 watts, and wouldn't use anything less than a 6S set up.
Taking into account the 1000Kv PNP version, if you want to go with a 4S set up, and want to keep things as light, or as cheap as possible, you can always go for something like the SK3 352 1250Kv. In any case I would try to use a higher Kv motor than the stock one, and possibly a high pitch SF prop, to give better pushing efficiency at low RPM. On 4S it is high doubtful that you would have some descent thrust, but these machines don't need that much to fly anyway. If AUW is kept around the 2.5kg mark, or even less, I guess 4S could work up to a point.
For a 6S set up I have the Tiger Motor MT2820 830Kv, and in this range I was not able to find a cheaper option that is rated for 6S. This motor can easily spin a 10x7SF prop on a 6S pack, and I guess would be the ideal middle ground between what I have done, and a 4S set up. Plus, it will give you a much higher efficiency than 4S.
Sadly, the Ranger is a tad too big compared to the size of the prop that can be installed. In this case, the most efficiency will not be had from a high Kv 4S set up with tons of batteries, but from a low Kv 6S or even 8S set up. I have yet to see how I will achieve the 2h flight time I want, so I will test a 10S set up, and if I don't burn out the motor I'd call it a good day.
|Apr 07, 2014, 07:36 AM|
On a side note, I've updated the top of the first post with a link to the Instruction Manual, just in case anyone is interested in checking it out.
Tomorrow I should have an update including stiffening the spar and possibly the autopilot installation, and some wiring tidying up.
|Apr 07, 2014, 09:57 AM|
What's the diameter of the wheels? Want to use a larger wheel for a bumpy grass field.
How much spring is there with the rear wheel strut? Think it would damage the rudder on a hard landing?
Waiting for mine to arrive.
|Apr 07, 2014, 01:48 PM|
For the rear wheel to damage the rudder it will take some SERIOUS bashing, I just don't see it happening even on a harder landing. The spring is quite stiff, and it has quite a lot of travel. Unless you attach some big weight right at the tail, there is no way the plane alone can push it down so much that it damages the rudder.
Here is a quick demo video of the landing gear:
|Apr 07, 2014, 08:02 PM|
Arxangel, thanks for excellent review.
I've planned order one of it for autonomous flight for imagery jobs.
Do you would planning fly it by APM or another autopilot?
Regarding plastic airframe, could you please tell me how resistent it is? I Mean, I need do some holes at botom side for Cam lens pass, I will need do some reinforcement there, in your opnion?
And have you any skywalker to take pics "side by side" with it? I don't know how much bigger is internal space. Need comparing for sure that my Cams/equipment will fit into.
Thanks a lot in advance.
Cheers from Brazil!
|Apr 08, 2014, 02:50 AM|
Nice review, many thanks for taking the time.
You used new control horns but retained the stock pushrods and clevises. I was not impressed with the clevises on the Raptor, are these any better?
The main weakness of the Raptor is the wing to fuselage join with the 4 small bolts not even at the edges of the fuselage. They easily tear through the wing in a crash. Is this join more durable on the Ranger?
ECODRONES - the best feature of the Raptor is the blow moulded fuselage it is amazingly strong and durable, that is the reason I am interested in the Ranger.
|Apr 08, 2014, 03:05 AM|
As for an autopilot, yes I will be using the APM for now, but will probably move on to a Pixhawk later on, even though the APM does a great job on planes.
As for the fuselage's resilience, I have a lot of first hand experience with the Raptor. I've crashed it nose first at speed into the ground, I've crashed it in bushes, trees, hills, balconies, you name it, I've probably hit it. The only indication on the fuselage that SOMETHING has happened are a few scratches on the bottom of the fuselage. I am stunned at how strong the fuselage is.
When it comes to drilling it for the camera, I do not foresee any problem with its durability, but just in case I would put fiber tape on the fuselage seam just near the cut.
Here is a picture of a comparison between the Ranger and Raptor fuselages, as you can see the Raptor's fuselage looks very nice, and you can hardly tell that it has been through so much crashing.
|Apr 08, 2014, 03:08 AM|
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