Hurricane EP550 Review

Written by Nigel Fraser Ker Monday, 26 February 2007 00:00

EP 550

Introduction

Now, from the makers of the Zoom, Shogun and various other successful models, comes something much bigger - the Hurricane EP 550 electric helicopter. With an overall length of just over 1m, a main rotor diameter of 1110 mm and fitted with 50cm blades the Hurricane is just a little smaller than a 30-sized helicopter and suitable for beginners and intermediate pilots alike. One small point for anyone new to the sport is that this helicopter uses eCCPM (Electronic Cyclic and Collective Pitch Mixing) so a suitable transmitter will be required although most have this facility these days. The model comes under the category of ARTF (almost ready to fly) although ‘partially assembled' might be more accurate since installing the radio gear on any model takes a good few hours.

Build

Opening the box I was immediately pleased to see that the canopy was pre-painted - painting not being my favourite pastime! To save weight it is made from a fairly thin and potentially brittle plastic (possible ABS or Styrene) of the kind previously used on the smaller Zoom/Shogun rather than the heavier at more rugged plastics used on larger helicopters such as a Raptor. I was impressed by the airframe which was made of strong plastic frames fastened together with high-quality cap heads and countersunk bolts. I was also impressed by the cyclic controls which were not only virtually slop free and smooth in operation but were also designed for push pull operation - a design which minimises the side loads on servos and thus increases the life of their bearings. The gear train incorporates an intermediate shaft between the motor and the main gear, which reduces the size of the main gear although I should imagine the extra friction will slightly reduce battery duration. The preassembled tail gearbox was also smooth running and slop free.

The manual gives complete assembly instructions that are sufficient to allow the model to be completely rebuilt if necessary although the English suffers from the occasional quaint misspelling (in common with many products from the Far East). The manual is illustrated with 3D CAD drawings that are very clear and should give few problems even to an inexperienced pilot. The only thing I was a little concerned about was the fact that no indication was given about the use of Loctite. Any beginner assembling this helicopter should bear in mind that any fastener that is likely to vibrate to loose should be secured with some form of engineering adhesive. One other note of caution for beginners is that only a judicious amount of force should be used when screwing self-tapping screws into plastic.

I'm happy to say that I found the assembly of the helicopter extremely easy and after just three or four hours I was ready to begin the work of completing the electrics. Beginners should note that compared to smaller helicopters such as the T-Rex, the larger size of the Hurricane 550 EP means that construction is less fiddly and the parts are more robust.

On the basis that most people would not be fitting expensive servos to this helicopter, I decided to opt for the fairly economical Futaba S3152 digital servos for the cyclic controls but chickened out on the gyro and chose the ubiquitous GY401 plus the S9254 servo for the tail - I wanted the tail controlled by something that I knew well so that I could accurately assess its performance.

The various parts for the helicopter arrived in bags that were not numbered but were helpfully grouped by assembly stages. It's hard to resist making the odd change when you're building a model and I have to admit that I exchanged Nylocs for the plain nuts rather than using Loctite on them. I also took advantage of the available length within the motor fixing holes and replaced the original cap head screws with longer (M3x8) ones and replaced the servo ball link self-tapping screws with M2x8 ones for added security. The original self-tapping type may be sufficient but being a ‘belt and braces' man I thought I'd take the opportunity to upgrade them.

I had no problems at all with the preassembled components and noted, for example, that the flybar had been carefully centred which was reassuring. The self-tapping screws provided for fixing the servos in place were a bit of a mystery - they were rather short and their diameter was too large to pass through the mounting eyelets of the servos. This left me with a difficult decision about how to fix the servos into the airframe. In the end I opted for no rubber dampers or eyelets - I guess the success of this measure will only be gauged after my first crash with the model!

The model comes complete with motor, speed controller and BEC. The motor is an 800 KV outrunner and the speed controller which is rated at 50 amps is designed for a 22.2 V battery which was achieved by placing two 11.1 volt, 2250 mAh batteries in series. The speed controller is programmable and features a battery management system to protect the batteries from over discharge, a ‘flight mode' setting which enables the pilot to select between different types of aircraft, and a governor to regulate the head speed.

The BEC/voltage regulator, which had a switch fitted to it was supplied unmarked so I decided to test it before fitting it to the model. Its voltage output turned out to be regulated to 5.75 V and the switch was just to turn it on and off. Happy that I knew the function of all the various components I started fitting the connectors to the various power lines.

At this point it might be worth making a point, not about this particular model but about electrics in general. Beginners constructing their first electric model should note that when soldering the electrical terminals onto the cables for the battery, speed controller, etc a suitable soldering iron is required. When I'm teaching, I see a lot of soldering work which has been done very badly and as a consequence can be either unreliable or not work at all. Your soldering iron needs to be sufficiently powerful to get to the components you're soldering hot enough to allow the solder to flow freely between them. A little soldering iron that you might use to solder electronic components onto a printed circuit board is not sufficient. Since copper is such a good conductor of heat the cables will tend to lead the heat away from the area you are soldering. Therefore, get an iron which is up to the job!

Set Up

The setup presented no problems at all. In common with most modern pod and boom helicopters the Hurricane has a clockwise rotating head and the pitch increases when the swashplate moves up, so no surprises there. I used the same pitch settings as recommended in the manual and initially set the tracking by eye (if you're careful to make sure that the flybar is exactly horizontal and you set the pitch of one blade to 0°, I find it quite easy to set the other one up so that the tracking is near enough bang on). With the batteries in place the balance of the model was near enough perfect so I was ready for a range test.

Flying

Having checked the range I was ready for the model's first flight. I decided not to use the built-in governor, preferring to use the throttle curve so that I knew exactly what was going on. My first few hops were done with a straight line throttle curve (i.e.0,25,50,75,100) but the head speed was rather low and I ended up using a rather more aggressive one (0,70,80,90,100) and this proved to be fine. The model flew extremely smoothly in our back garden and gave me no cause for concern at all - it was a real pleasure to fly. The care I took during the mechanical and electronic setup paid off and after just a few adjustments to the sub-trims the model was as steady in the air as a simulator!

The model comes with wooden blades that were well balanced and needed no weight added. However, I wasn't sure how much aggressive 3D flying they would take so I decided to limit the flight tests to a fairly gentle series of manoeuvres of the sort that a beginner/intermediate pilot might wish to perform. I set up the idle-up throttle curve to 100, 90, 80, 90, 100 and the pitch curve to a straight line (i.e. 0, 25, 50, 75, 100) and went out for another flight, this time trying some inverted flying.

Again, inverted flight presented no problems and the model was as stable in an inverted hover as it was the right way up. I suspect that the batteries I was using (an anonymous set from the Far East provided for testing purposes) could have been better which would have given me a higher head speed which I think the model needs to get the most out of it. I found that the model performed moderate aerobatics such as loops, rolls, pirouetting flips, etc. very well and I was surprised by its stability which during normal, non-aggressive flying was absolutely rock solid. I would go so far as to say that it is one of the most stable models I have flown, certainly in the form that I tested it anyway. The S3152 servos that I used seemed to be perfectly adequate and in simple manoeuvres gave it quite as snappy looking performance. The tail also behaved itself well giving the pilot the sort of confidence you get with all good machines. Take a look at the demo video (see below) for an idea of what the model is capable of.

Autorotations were easy, if rather brief affairs, the light wooden blades having rather too little inertia to do much more than get the model down onto the deck. However, I think it's worthwhile saying that a beginner could use this model to learn to autorotate without too many problems.

After flying I checked the temperature of the battery and motor which were fairly warm. I was testing in a cold climate (England in February!) but for anything warmer I would advise pilots to cut cooling holes in the canopy as indicated in the instructions.

Conclusion

So how do I feel about this model overall? I'm going to stick my neck out here and say that it is probably one of the best small helicopters I have tried. In the form I tested it I don't think it could be described as a top-flight 3D machine (it was fitted with wooden blades for a start!) but if you are looking for a helicopter to use as a first machine or if you are an intermediate pilot who wants something to have fun with an electric then the EP550 will suit you fine. I would only recommend going up to something like the T-Rex 600 if you were going to be flying more aggressively than the sort of flying shown in the demo video (see link at the end of this article). The EP550 is far cheaper than a T-Rex 600, more stable and less fiddly to build than the T-Rex 450 series helis, it is cleaner, cheaper, quieter, and more practical than just about any nitro machine and its build quality is excellent. (I am currently building a 1/6 scale gasser helicopter for which I paid nearly $3,000 and I'd love to know why the manufacturers of that machine can't achieve the build quality that you get with the Hurricane!) The only real downside I can think of is that it is too big to be an indoor machine.

So, would I recommend this machine? Yes I certainly would, with the only caveat concerning parts availability...at the moment I don't know of any local (that means the UK for me) supplier that stocks this helicopter and so if you're thinking of buying one of these I would make sure that you can get hold of spare parts. This may be mean ordering them from the Far East and if you're willing to wait for them to arrive then fine. Personally, I hope these machines appear in local stores fairly soon as I think this model could be a real winner.

To see the model in action, take a look at this video

Nigel Fraser Ker
Heli-Lessons
February 2007