Mark's aircraft

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page updated: 2005.11.20

aircraft - helicopters - hornet
aircraft - indoor - hornet

early electric power gliders helicopter indoor technology future

eco8 hornet

selection

My 2nd heli. Even before going for eco8 I had considered an indoor mini heli lie the ikarus piccolo. I had rejected the idea because of the extra difficulty involved in handling something that small and fast. The piccolo always looked a bit vague anyway. Feb 2001 I saw some hornets flying. They were a lot more positive, and looked better engineered all round, including a shaft driven tail rotor and 9 ball races. I wanted 1. It also gave me something to fly indoor - the eco8 being really too big. I bought the full package (excluding standard Tx) for just less than £300.

construction

This thing is mostly carbon fibre and super glue with a bit of plastic thrown in. Even the main shaft was originally 3mm carbon.
A relatively straightforward build - mostly assembling the various bits onto the chassis with super glue (sparingly) and double sided tape. It is essential to make sure that all of the moving parts move freely, requiring repeated dismantle/assembly of some parts eg. the fully teetering rotor head. The ball links need freeing off, but not by sanding - the instrutions recommend just nipping them up with pliers, whcih seems to work OK.
The main rotor shaft should be retained with a bit of silicone tubing slid up it, rather than the glued collet supplied in the kit. This allows the gears to disengage when they really need to.
I relocated the tail servo mounting plate from the tail boom itself to as much on the chassis as I could, making the tail boom more independent for maintenance. The tail rotor bevel gear drive is a little miracle in itself, with very few parts - it just works. I discarded the transparent plastic tail skid as a bit too bendy, and initially did without, but you really do need to protect that tail rotor. Later I fitted a bit of red control snake outer, and finally a 3mm carbon tail skid.
I shortened the front legs by about 2mm to make it stand with its tail a little high, reasoning that it would help to take off pointing forward a little.
7 cell 8.4V 700mAh nimh power pack driving a 300 motor through a 5A speed controller.
4 channel Rx with a piezo rate gyro in the tail control.
I couldn't be bothered to paint the canopy.

flight

I fitted the piccolo training undercarriage of carbon rods and ping pong balls, and extra weights just inside the paddles which is supposed to add a bit more gyroscopic stability and slow the control response a bit. This of course made it heavier, meaning there was only just enough power to lift off at the start of a charge. I tried it in the garden, having several crashes, but it is a remarkably ruuged little beast. These tend to displace the paddles, which should be straightened before having another go. Also the anti rotation bar taht keeps the swash plate push rod in position tends to break away, requiring regluing. The other thing that tends to happen is the carbon main shaft splits. Unfortunately, this is not immediately obvious, as everything remains attached, but there is now a highly bendy/twisty thing between the motor and the main rotor. 1 of the main effects of this is to cause a tail oscillation. I thought it was due to cheap gyro, eventually learnt to recognise the symptoms and replace the shaft. Finally I found some 3mm silver steel and made a replacement metal shaft - not easy, drilling 1mm pin holes through a 3mm steel shaft. This added yet more weight, but the control was much more positive. The modern kit now has a metal shaft.

February 2002. Started using the FMS flight sim, which is great for getting practice time in.

Eventually the main blades started to look a bit bashed, and I replaced them. I have broken the tail boom in the middle. I've bought another, but it is currently flying OK with it taped up - the internal tail drive shaft must have survived.

At some point I realised that the ping pong balls were unnecessary, and removed them, saving a bit of weight and adding duration. The remaining sticks tended to stick in the grass a little, so I would usually take off from a folded newspaper. I learnt that the only thing to do with any heli is to leap into the clean air - trying to lift off gradually leads to disaster in the ground effect.

I have probably learnt most of my heli flying from this little thing. certainly going back to the eco8 seemed really easy. I have now removed the training sticks and can reliably fly it tail in and nose in, although I'm only just starting to join the 2 together.

statistics

Here are some more photos.

And video.