Sloping Off - December 2004
Travails of a Helicopter Pilot
or Robbe Eolo Part 2, by Clive Spencer
(Click here to read Part 1 first)
Isn't the Internet a wonderful thing? There is so much information to be had from it, good & bad. I punched 'Robbe Eolo' into the Google search engine and was astounded by the amount of information available regarding the good and not so good points of this particular model. The good part appears to be that it flies extremely well in standard form without any mods needed. Why then are so many upgraded parts being produced by specialist firms, mainly at extremely inflated prices? It appears that the standard model was envisaged as a trainer not a 3D machine and as such is quite adequate for the job as intended, but not for charging around the sky in the demented fashion you see at some fly-ins.
I also found a great deal of good advice from Eolo owners at the various forums dedicated to heli flying. A couple of tips gleaned from these were a third bearing addition to the main shaft and an U/C strengthening mod. The parts for these cost all of five pounds and an hour's work. The mod kit for the third bearing from one of the specialist suppliers was priced at sixteen pound alone. I also made up a training undercarriage from two carbon rods and four air-flight plastic golf balls.
My first effort at heli flying was at King's Park one Friday evening with Neil Longman & Phil Wheeler as mentors. This was a process of slowly increasing the head speed and slowly rocking the cyclic controls to get a feel for their sensitivity and effect. The Eolo is set up as Mode 2, so the right stick operates in the same manner as an aircraft, fore & aft for pitch, left & right for roll. The left stick fore & aft for throttle/collective & left & right for rudder. Sounds easy doesn't it? Well let me tell you that it isn't, it's akin to balancing a ball bearing on an upturned saucer. So here we go again, bit more collective, rock her on the skids, keep her on the ground fool, keep the tail towards you, tail servo reversed? No, look at the nose not the tail, dolt. Phil's words not mine. Getting brave now, more collective, HAA No, she is flying? Panic, what to do, close the throttle, that's what you do with a proper aeroplane? Crash. Wrong? The first lesson learned the hard way. Go home and read 'Radd's School of Rotary Flight' again. Repair skids.
The next foray into the world of heli flying was at King's Park on the following Friday evening where we all stood around waiting for the wind to drop, which it patently refused to do. Phil managed a very nice demo of heli flying but that was the sum total for the evening. I trotted off home contemplating the dubious merits of fishing as an alternative to this model-flying lark. On unloading the car I had the feeling that the wind had eased slightly. Should I make an attempt to hover the heli in the front garden? Why not, it couldn't hurt could it? Mark out a box on the drive per Radd's instructions, set the copter down tail in, take a deep breath and slowly increase the revs/collective. The copter goes light on its skids and I achieve some semblance of control and some short hovers. After two battery packs have been used I decide discretion is the better part of valour and quit whilst the going was good. This was a huge step for me and I was like a cat with two tails that evening. The only down side to all this was the very short duration I was achieving using the standard kit motor, which was also very hot after each flight. The brushed motor supplied in the kit was obviously not going to last very long. I mentioned this to Neil Longman who said that he knew a man with a second hand Kontronic Twist 37 motor & speed controller for sale, the very motor designed for the Eolo. Well he would wouldn't he? The man turned out to be Phillip Wheeler, demon heli flyer extraordinaire, who proceeded to extract huge amounts of mazzuma from my wallet for said motor. Fitting the new motor was a battle in itself due to thread locked bolts. Having finally won this particular battle I decided to see how it's performance differed from the original kit motor. How do you get readings for amps & revs from a helicopter without it disappearing into the ether at a high rate of knots? Easy, you tie the skids to your wife's decorative cast iron patio table when she's not around. I connected up the battery via my Wattmeter and opened the throttle. Several things happened in quick succession, the rotor accelerated to some horrendous head speed, the heli, screaming like a banshee, did it's best to hijack the wife's table, finally two of the four cable ties snapped & the heli started leaping about like a demented Redskin doing a war dance. Thoroughly shaken I shut the throttle andwent for a change of trousers. It would appear that this motor is extraordinarily powerful compared with the stock motor. Having calmed down and changed the cable ties I tried again, opening the throttle very gingerly this time. At an opening of 10% the head speed was over 2000 RPM, 300 more than the stock motor flat out, and this at a cost of only 14 Amps. Now one of the neat things about Kontronic speed controllers is the ability to program them. On my version there is a heli mode available. Using this you can limit the revs to a set amount and the controller will ramp up slowly to that setting. This means that no collective/throttle mixing is required, as the left stick will only now be used for the collective as with the full size heli. Very clever.
Having achieved some form of control and hovering flight, I decided that this lark was not so difficult after all and I should continue with my front garden practice. I found it a little strange at first that the speed controller now set the motor revs and was not controlled by the throttle stick. As I said before, as soon as you start to open up the throttle slide the speed controller ramps up the revs to a pre determined setting, in this case about 2000 revs and the copter just sits there waiting for you to input the collective to whatever amount you require. After my previous effort, and full of confidence I decided to further my helicopter training with another go in the garden. I input some collective and the Eolo begins to hover. Brilliant, this really isn't so difficult is it? Then things begin to go pear-shaped. A gust of wind pushes the copter to the right towards Billy my Lurcher, who takes off at the speed of light in the opposite direction. OK, no problem, a little left cyclic should correct this? It doesn't, more cyclic & MORE. Suddenly the wind drops & the Eolo move sharply to the left. Moving fast the copter scythes through the wife's new camellia like a demented buzz saw shredding bits of plants in all directions. I close the collective but the speed controller does what it's designed to do and keeps the rotor turning at 2000 revs until I manage to turn it off. Oh dear I thought?? The flowerbed looks as if a bomb has hit it. I'm left with the Camellia pot with a 150mm bare stem in it, but at least the label was intact Now if I stick the top piece of the plant in the pot perhaps Erin doors won't notice the damage until a replacement can be found or a plausible excuse thought up. Perhaps I can pin the blame on Billy? Some hope. At this point fishing appears to be a very good alternative to heli flying.
