Like many of you, I subscribe to e-mail updates from the good folks at Hobby People.
When I saw in one of those e-mails that which you are about to learn about, I was utterly floored. I mean, come on. Are you all trying to tell me that a coaxial helicopter is capable of high performance, fast forward flight?
And in wind, yet?
The Extreme-Flyers X350 5A2 and it semi-scale variants may well be remembered in the annals of model aviation history as one of the most important developments since radio control itself.
In four-channel mode, this rather large coaxial flies like most other coaxials, that is, reasonably gentle and stable for new pilots and for indoor flight.
Kick in the fifth channel on the transmitter and the gyroscopically controlled tail rotor comes into play. It both stabilizes the helicopter in windy conditions and pitches the nose forward via a built-in mix with the forward cyclic. This in turn transforms the X350 from a training platform to an outdoor, fast forward-capable helicopter which Mike Greenshields, vice president of product development and marketing for Global Hobby, describes in their demo video as a "beast."
Regarding that video: To silence the skeptics, Global Hobby produced a video which I've linked to at the end of this article. In it, Mike is hovering the X350 nose in inches from the front of a large portable floor fan. Yes, the fan is running. It's almost too amazing to be believed, but the proof is in the video. Not only is Mike's example hovering well, it isn't bouncing around any more than a standard helicopter might.
As I've pointed out, Extreme-Flyers has two other variations. One is the X350 5B1 military attack helicopter and the other is the X350 5B2 done up like a Swiss Army rescue chopper. All are mechanically identical. Global Hobby only distributes the 5A2, at least so far.
If you're ready to relearn everything you thought you knew about coaxial helicopters the way that I just did, read on!
School is now in session.
|Rotor Diameter:||18.74" (476mm)|
|Weight:||15 oz (427g)|
|Servos:||Eight-gram analog micro (x2)|
|Transmitter:||Extreme-Flyers five-channel 2.4GHz aircraft with switchable fifth channel for tail control, digital trim tabs and GFSK digital protocol technology|
|Receiver:||Combined with the 5-in-1 onboard mixer|
|Gyro:||Heading lock combined with the 5-in-1 onboard mixer|
|Battery:||11.1V 3S 850mAh lithium polymer with cloned Deans Ultra-Plug connector and JST-XH balancing lead|
|Motors:||Brushed 180 for the main rotors upgradable to brushless, N30 brushed for the tail rotor|
|ESC:||Combined with the 5-in-1 onboard mixer|
|Minimum Skill Level:||Beginner in four-channel mode; intermediate to advanced in five-channel mode|
|Typical Flight Duration:|
|Manufacturer:||Extreme-Flyers Hobby, 2/C, Changping Chamber of Commerce Building, Changping Avenue, Changping Town, Dongguan City, Guangdong Province, China 523560|
|Distributed By:||Global Hobby Distributors/Hobby People, 18480 Bandilier Circle, Fountain Valley, California 92708 USA|
The beautifully printed display box has some great stuff waiting inside:
Extreme-Flyers has done a fine job of creating an eye-popping display box. It's a sort of satin finish with beautifully printed graphics.
One thing that never fails to cause me to raise flags, sad to say, is mangled English on the packaging and/or documentation. It abounds on both in this case. Even the warning printed on the main rotor blades is somewhat mangled and throws in a capitalization mistake for good measure: By collision, shut immediately down throttle to prevent electronic damage. keep away from moving parts." However, given the fact that Global Hobby enclosed a quick start guide which was almost certainly written by the crew in Fountain Valley, perhaps we'll see corrections to future production runs.
As far as the contents of said box are concerned, we're talking nice.
Everything except the transmitter came neatly and safely packed in a pulped paper tray much like an egg carton. The transmitter came in its own polycarbonate "clamshell" container while the documentation came loosely atop the main tray. It's a wonderfully simple sport transmitter without the often intimidating setup required of a computer radio. The documentation itself, while suffering somewhat from the aforementioned mangled English, is clear and concise. It will doubtless aid budding helicopter pilots with learning the basics of flying the X350. There are plenty of tips and tricks for setup, maintenance and repair, all important considerations for those new to the hobby.
Speaking of the X350: In terms of size, this is one big bird which is nearly as large as a 400-series helicopter. The main rotor blades are made of a tough, nylon-filled composite able to withstand the kinds of beatings a new pilot will dish out. They fit loosely in their grips and feature built-in stops which prevent the blades from pivoting too far.
At least that's what they're supposed to do.
If the stops are damaged in even a slight tipover, there's a very real risk of the upper and lower blades coming in contact with one another.
According to the video, the stops further aid in decreasing so-called "lag time" which in turn results in more positive control. It's a serious, sinister looking model from nose to tail. In fact, except for some gold and silver accents on the canopy and a bit of silver script and accents on the main rotor blades, it's a study in black composites, plastic and aluminum.
Darth Vader, your helicopter is ready.
Many RTF models come with transmitter batteries. The X350 doesn't, so four AA-cell alkaline batteries are going to be necessary to fire up the transmitter.
That full-sized transmitter with its digital trim tabs and low-battery alarm is extremely light in weight, even with the batteries installed. The sticks feel surprisingly good; they're nicely damped and have a feel associated with a much more expensive unit. Once the batteries are installed and the protective films removed from the decorative metal faceplates, the transmitter is ready to rock. The transmitter and receiver are bound to one another at the factory, but should the two ever need to be rebound, the manual clearly explains how.
I immediately noticed the words "SPEKTRUM 2.4GHZ GFSK TECHNOLOGY" on the face of the transmitter along with the "GFSK" acronym by itself. A quick Google search turned up the meaning of GFSK, but no connection with Spektrum. It refers to Gaussian frequency shift keying which is a digital data protocol most often found on Bluetooth devices.
It is indeed not based on Spektrum technology as one might think and which Mr. Greenshields was kind enough to verify. Rather, it's a misprint. The factory meant to say "spread spectrum."
Extreme-Flyers makes the transmitter available in both Mode 1 and Mode 2 stick configuration. My North American-spec sample was, quite naturally, Mode 2.
Beginners: This simply refers to the stick function. In Mode 2, the right stick controls ailerons and elevator while the left controls throttle and rudder. The sticks retain their function in Mode 1, but they're swapped from right to left, placing throttle/rudder on the right and aileron/elevator on the left.
Needless to say, the flight battery will need some charging. The X350 comes with an 850mAh three-cell pack with a claimed discharge rate of 22C (to beginners, that represents twenty-two times the capacity of the pack for short bursts) and a rather nice DC charger with AC adapter. The charger has balancing ports for either two- or three-cell packs rated at less than one ampere. When everything is plugged in, a red status light glows red and three green LEDs, one representing each cell in the pack, begin to flicker rapidly. When they're burning steadily, the pack is ready to fly. Mine was ready in about 45 minutes and a quick check with my cell balancer verified the fact.
Shall we do a bit of flying?
Once the transmitter is swtched on, the battery plugged in and the canopy reinstalled, the system is armed by fully (and I would add carefully) advancing the throttle stick for a few seconds and returning it to full stop. Since the maiden flight would be in my living room, I double-checked the transmitter's tail motor switch to assure that it was off.
While we're at it, this would be a good time to ensure that the servo reversing switches are all set to the normal position. Since each X350 is tested at the factory before shipping, all my switches were A-OK.
From this point on, slowly advancing the throttle will result in spinning blades so beginners, please take note.
Throttle response is extremely smooth; ditto the servo response. In fact, the servos seem to be superb units with their quiet, fast operation, but they're identified only by the glossy Extreme-Flyers label on the side of the case. Time will tell how well these will hold up, but for now, I wouldn't hesitate to install these servos in any small model.
The head speed on the X350 is noticeably faster than any other coaxial of any size that I'd ever flown; I can only imagine how fast these blades would be spinning with the brushless motor upgrade!
Though pre-tested, my X350 needed some minor cyclic trim via the digital trim tabs on the transmitter. Once trimmed, the X350 hovered hands off just like Mike Greenshields' video example.
There is a lot of throw on those servos for use in outdoor flight, so it's really easy to overcorrect in a hover even though the pushrods are attached at the innermost holes in the servo arms. It takes a steady hand to maneuver in a room. I've flown any number of coaxials of different sizes in my living room, but the size, head speed and sensitivity of the X350 limited my flying to some hovering and simple forward manuevering. Beginners who are just learning the basics are well advised to have a large indoor area free of obstacles at their disposal.
As one gains confidence - and if one really wishes to do some hairy outdoor flying - the pushrods can be located to the outer holes of the servo arms. The example in the Hobby People video was flown in the stock configuration and my own video follows suit.
There was a distinct smell of hot electric motors after that first flight, but the smell and excess heat were gone by the second flight. I chalk it up to the motors simply breaking in.
My first attempt to fly the X350 outdoors occured on a beautiful afternoon with light wind, perfect conditions to put the model through its paces.
With the tail motor switched on, the effect was astonishing.
Here was a coaxial helicopter hovering quite well in a good, steady breeze. Though it hovered better than the extreme example hovering in front of the fan, it didn't fare as well as one might expect of a standard helicopter. It was no less astonishing; no other coaxial I know of would have been able to maintain a controlled hover in similar conditions, let alone fly.
It doesn't take much forward cyclic to get the X350 on its way, but flying into the wind and lots of throttle make it want to climb, especially since this is a fixed-pitch machine.
Coordinated turns are done in the same way as a standard helicopter, but it banks far less and rotates via the rudder much slower. It's happiest with some throttle going into turns; throttling down out of turns causes a weird sort of wobble on its rotational axes if done improperly. That effect seemed to be more noticeable when I came out of turns with the model's flank to the wind. Returning to a hover with the flank into the wind required a lot of opposite cyclic.
It's definitely a different feel than that of a standard machine.
After a few minutes of simply getting used to the feel, I was blasting the X350 around a smallish field at my local park and compensating for the handling differences. Speed is definitely an asset; the faster I flew the model, the better it handled the wind. All the while, I was simply awestruck at the speed, power and overall manueverability. Coaxials simply aren't supposed to be capable of such moves, but no one told that to the designers at Extreme-Hobby.
While I have no problem doing spot landings and low-speed manuevering with my 400-class helis, the X350 in a breeze was more of a handful to handle since it's naturally less responsive than a standard helicopter. Great for beginners to be sure, but it'll take a bit of adjusting on the part of an experienced pilot. This isn't necessarily bad. It's just different and will come with practice. I will almost certainly move the pushrods to an outer servo arm hole at some point and report back via the comments section.
The wind was picking up as the battery was winding down, so I thought it best to pack it in before the video shoot.
Thanks to my friend Ken Alan, the opportunity came soon with nothing less than a broadcast-quality camera!
The X350 still exhibited some of its slightly twitchy hovering tendencies both indoors and out as well as the strange little multi-axis wobble coming out of forward flight. In fast forward flight, the X350 was nearly as stable as a standard helicopter, but the relatively limited outdoor space required I keep the speed down.
I was determined to really wring out the X350 at a nearby soccer park. Unfortunately, Ken wasn't able to break away to shoot video.
The X350 was, at last, in its element. Forget about hovering and low-speed manuevers. This is a fast-forward machine the equal of pretty much anything even remotely this size. It's almost more airplane than helicopter in this regard.
When Mike Greenshields described this model as a beast, he wasn't kidding. With sufficient room and sufficient throttle, the X350 tracked as well as any helicopter and it did so with some serious speed. It still showed a tendency to climb with the throttle, but pitching the nose down and hitting the throttle brought it closer to earth.
Tracking the model in flight was a different story. The all-black finish makes it a bit difficult to do so, but it isn't impossible. It just takes concentration.
Suddenly...disaster! As I was coming out of a dive, the upper and lower blades managed to contact themselves in flight, resulting in momentary loss of control and a semi-controlled crash. Damage was limited to the canopy, blades, drive gears and shafts.
Mike had the same problem with his sample. As I'd pointed out early in this review, the blades are incredibly tough except for the pivot stops near the blade grips. Even a slight tipover might damage them. If the stops become damaged, the blades may contact themselves due to the intentionally engineered tendency of the blades to pivot somewhat in flight, hence the loose mounting. I've been told that the factory has been made aware of the problem and Mike is seeing to it that future production runs feature beefed-up blade stops. If not for the fact that the stops had been further damaged by the crash, the blades would still be useable.
Another good way to avoid strikes is the use of the longer mainshafts necessary for use with the brushless motor upgrade. They're available as a set under part number 5UP005.
As for that upgrade, it's complete with two motors, ESCs and a Y-harness, but it's pricey at US$139.99. That nearly doubles the cost of the model, putting it near 400-class RTF territory. It might be worth it for advanced flyers who want to wring out the most performance possible, but for now, the brushed motors seem to work just fine.
The inherent stability, simple transmitter, ready-to-fly convenience and printed flight instruction make the X350 a fine beginner's helicopter, one which will won't be relegated to the closet as the pilot's skills grow. Intermediate and advanced pilots will find this helicopter to be just the thing for tossing into the car for some high-speed blasts at the club field or the park.
A beginner with some previous experience on a small indoor coaxial will have no trouble making the transition to the X350, but a raw beginner might have a bit of trouble mastering the sensitive cyclic response. It might be best if someone with no experience whatsoever were to enlist the help of an experienced pilot.
The Extreme-Flyers X350 5A2 is a rare model that does more than one thing very well. It's a perfect machine for indoor flying (in a suitably large space) when the weather is uncooperative, it will teach beginners the basics of four-channel R/C coaxial helicopter and will put on a very impressive show of forward flight for anyone who is comfortable flying a helicopter or airplane.
I'm giving this groundbreaking model two thumbs way, way up. The blade issue is an easy fix, avoidable with some care and/or an inexpensive pair of upgraded rotor shafts and the factory is already aware of the situation. I can tell you this: Once my example is repaired, it's going to the field with me every opportunity I get. It's incredibly fun to fly and amazingly fast and nimble. Perhaps best of all, the X350 will most assuredly blow some minds, especially those convinced that a coaxial helicopter is unsuitable for outdoor flight, let alone fast forward flight.
Many thanks go to Mr. Mike Greenshields, Global Hobby's peerless vice president of product development and marketing for providing ths sample as well as for technical assistance, not to mention the parts I needed after the crash. My friend Ken Alan of Kaminsky Productions in Cathedral City, California was kind enough to take a few minutes out of a busy day to set up a minicam for the video shoot. Our admininstrator, Angela Haglund, is the catalyst through whom all these reviews pass and of course, you are the reason we work to bring you these reviews.
Among the great attributes of the X350 are the following:
Minuses are few:
|Jan 06, 2012, 08:35 AM|
GRREAT Review Ralph! I am an early adopter of the X350 and thrilled with the performance!
|Jan 06, 2012, 03:17 PM|
|Jan 06, 2012, 06:39 PM|
I'm still waiting for the parts to fix mine - Mike at Global offered to send them to me and the warehouse and stores are awash in parts - but when they get here, I'll pick up another li-po or two and just have a ball with this bird.
It really takes throttle management to keep it at the altitude you want, so my next step is to practice with it until I get it going where I really want it to go. Yesterday, I flew the T-Rex 450 Pro clone I reviewed a couple of months or so ago. It's clearly more precise, but a lot less forgiving.
|Jan 06, 2012, 07:55 PM|
Just be careful to check the blade stops if you happen to tip it over even a little bit. The leverage combined with the power might be all it takes to tweak them. There's a Hobby People store sorta-kinda near where I live and another in San Diego close to my sister and brother-in-law. Some spare blades are definitely going to be in the parts bin before long.
In any event, wait until you fly this thing outside in fast forward flight if you haven't yet done so.
|Jan 06, 2012, 08:12 PM|
|Jan 06, 2012, 11:39 PM|
The Banning Pass, CA
Joined Sep 2006
Issues with X350
Been having issues with my X350. After around 15 to 20 flights, the motors start cutting out intermittently in flight, usually when flying out around 75 ft away or more, and sometimes bad enough to cause a crash. May be an ESC issue, don't know for sure. Luckily, the two crashes I've experienced due to power loss caused no damage to the heli, except for the canopy, but now after approx. 30 flights, the motors are not making enough power. Those 180s sure do run hot, may be overburdoned for the application I think. I'm an experienced heli pilot, and I really dig this thing, it's kinda like the Slow Stick of 450 class helis. Never did care for brushed motors in helicopter applications, flashback to the Shogun 400 with its stock brushed motor, never did make enough power, or last very long. Going to unfortunately have to shell out some dough for the brushless kit, but I was foreseeing having to do this anyways. Hopefully the issue I was having will be alleviated by the brushless kit, and not be some other issue with the radio Tx/Rx.
|Jan 08, 2012, 12:57 AM|
There are some even larger coaxials of this type on the way including a 500-series equivalent. Should be interesting, so get ready for some really insane fun.
|Jan 08, 2012, 01:38 AM|
The Banning Pass, CA
Joined Sep 2006
RE transmitter issue
Yes, this is good to know, for my problem seems to me to be more radio related, since the motor cutouts seem to be a function of distance. Hope HP can do something for me.
|Jan 09, 2012, 12:37 AM|
USA, FL, Doral
Joined Jul 2006
|Jan 09, 2012, 10:34 AM|
I'd like to test one of these babies
I've spend my time modding blade cx3 and cx2 to fly well outdoors; even lost one of them in high winds
|Jan 09, 2012, 10:53 AM|
|Jan 09, 2012, 11:33 AM|
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