Alioth's Journal: The 'build fly crash' cycle

RC helicopter flying is, well, basically a cycle of 'build fly crash build fly crash'. They are unruly beasts, and ... well, with any RC model sooner or later you'll crash, but with helicopters, sooner seems to be the general rule.

I managed to snag a new HDX-300 kit off an ebayer (the HDX-300 is 300 size like the CP2, main rotor diameter of 520 mm), which is a really nice all fibreglass and alloy model, with a belt driven tail rotor. Doing the performance calculations showed it would be a really hot performer. So, last week, I spent two hours building, and it looked great! Here's some pics of the frame before I got the electronics:

The whole thing:
http://www.alioth.net/tmp/hdx300-1.jpg

Tail detail:
http://www.alioth.net/tmp/hdx300-2.jpg

Main frame and drive detail:
http://www.alioth.net/tmp/hdx300-3.jpg

Today, I got the electronics from my local model shop - a receiver, ESC and heading hold gyro. I basically lashed everything on to do the setup - get the heli balanced correctly, and set up the gyro.

The maiden flight was a total disaster. I hadn't really intended to maiden flight it, just get it off the ground a few inches to get the gyro set up correctly. The gyro had way too much gain which made the tail wag like crazy (but was mixing in far too little input from the transmitter, so while the tail wagged like mad, my stick inputs didn't really do much). Unfortunately, on one of these little hops I decided to try and keep it in the air a little longer to see how my latest settings changes had improved matters, but with the tail wagging... a wall jumped out in front of the heli.

I've never broken a hardened steel main shaft - I've used the HDX-300 rotor head system on the CP2 for about 3 or 4 months and had some tremendous crashes with it... but this time, I snapped the main shaft in two, just below the swash plate. Naturally the main blades were totally destroyed - it was utter carnage. Now I can't get the remains of the main shaft out because I thread locked the grub screws on the main drive gear, and I can't get them out (at least in situ). So I'm going to have to completely disassemble the frame...it was too depressing to do that today, so I'll do it next week.

Just another day of RC heli flying!

oops.

[TinaMarie]

You should be more careful with your main shaft. :) I'm sorry - stories like these are why I never had any desire to fly RC. It's just to easy to break things...

Re:

[Alioth]

Crashing is just part of RC :-)

I put it all back together last night/this morning, and made a successful maiden flight! Unfortunately the run up wasn't altogether smooth - I used the head as shipped with the kit and it didn't have the hardened main shaft - and the main shaft in that head didn't take even a sideways landing from 6 inches up, so it bent like a ... umm... well, it wasn't properly erect any more. Fortunately I have spare hardened shafts to put in the head, so I put one in and then it was ecstas