Monday, December 15, 2008

Berlin new year

I'll be flying off to Berlin during Christmas for work (im not being a 'scrooge'). Will be back next year.

This will be my first trip to winter-land, and i'll be alone mostly. I think this will be a much needed experience and also a good time for some self-reflection before embracing year 2009.

Besides work, i'll also be doing some visits. As you can see ive been researching...

Have also 'bookmarked' some of the places im planning to visit on my E71 (Nokia Map). Will be relying on the embedded GPS for navigation.

And i'll be ushering the new year at Brandenburg Tor/Gate!

Its wet & cold in Berlin now (4°C), i actually prefer hotter weather :\
Oh well, lets hope i don't get drunk and get frozen lying on the street :P

Incase im not gonna post again within year 2008, Merry Christmas & Happy New Year to all!

Sunday, December 14, 2008

Heli 3D: Piro Tictoc

This is a continuity of my previous article on piroflip as the skills required of piroflip & piro Tictoc are pretty much the same.

Piro Tictoc can be broken down to the following 3 steps
- Controlled pirouette while wearing 45° angled spectacle (Pun intended!)
- Time the flip
- Flip

Sounds familiar? ive broken down piroflip into 3 similar steps, without the 45° angeled spectacle, haha.

Im not going to re-post the tips from piroflip article, instead, im gonna talk about the notable differents. And i'd highly suggest the reader to be confortable with piroflip before attempting piro Tictoc.

Start the heli pirouetting, nudge the elevator forward when the tail is pointing side-way.

The 'Tic' with tail pointing side-way
After half a revolution, the tail will be pointing downwards, too much downwards the heli will be dropping like rock, either that or the heli will start drifting towards right. When neccessary, nudge forward elevator or give abit more collective.

The 'Tic' with tail pointing side-way downwards

Before allowing the heli to drift too far right (normally after too many revolution), time the heli for tail-in flip (similar to piroflip), the rest of the steps would be just nuding the elevator forward/backward.

Inverted 'Toc' with tail facing side-way downwards

Inverted 'Toc' with tail facing side-way upwards
Perhaps it would be easier to visualize the flow with this video (stick movements in mode 1).
The simulation was done with speed factor of 140%, but the video was recorded in 90% to allow easier viewing of the movements.

Compared to the piroflip video posted in the previous entry, I uses more extreme cyclic & collection inputs in piro Tictoc.

Thats all for now, Fly safely :)

Saturday, December 6, 2008

Heli 3D: Piro Flip

I hope the reader is comfortable with controlled pirouette already before attempting the tips in this article, if not, do check out the previous entry on controlled pirouette.

Piroflip can be broken down to the following 3 steps
- Controlled pirouette
- Time the flip
- Flip

I'd start with the heli in upright pirouette and wait for tail-in, then give forward elevator to flip the heli. As the heli is constantly pirouetting, aileron input will also have to be given during the forward flip. This will speedup the transition of the heli to inverted in one revolution (one full pirouette).

We want to be able to transit the heli from tail-in upright to nose-in inverted in one revolution. Using only elevator input will be too slow and may take more than one pirouette to transit.

While the heli is inverted pirouetting, i'd wait for tail-in again, then give backward elevator and aileron input to transit the heli to upright in one revolution.

Ive uploaded a video which shows transition of a stationary heli to inverted and vice verse in one pirouette (mode 1).

After successfully transiting the heli in one revolution, the heli may want to drift around, just rely on your controlled pirouette skill to flatten the heli.

And heres another video which shows sticks movement of full piroflip (mode 1).

Too much drifting around?

Somehow, faster piro rate (at a rate controller to the pilot) helps in making PiroFlip easier to perform.

And try to have more piro per flip. I'd do at least 2 piro before flipping. 2 piro would normally allow enough time for me to flatten or re-position the heli.

Heli 3D: Pirouette basic

Controlled Pirouette

This should be the first piro move to start with before attempting more challenging piro stunts. It is gonna be like learning to hover all over again, but with the rudder stick held down. It is very important not to skip this 'fundamental' skill if you don't wanna crash your heli into someone. This skill will also come into handly someday when the rudder malfunctioned in the air, ive safely landed my heli few times while pirouetting (tail rod poped out).

This section will cover some basics in controlling fast piro (high piro rate) and slow piro (low piro rate).

Fast piro requires holding down the rudder at extreme end, a good starting point would be 1 full piro (or slightly more) per second, set it up on the radio/heli to achieve that.

Give only elevator input in fast piro. More inputs from other sticks would just complicate things, unless you harness the force and nothing is too fast for you. If not, you want to be able to keep the heli as flat to the gound as possible with only one input.

The heli would be drifting around, compensate the movement with abit of elevator input at the correct timing to set the heli moving back to the initial spot. I like to give only forward elevator while the heli is upright pirouetting, so i'd give elevator input only when the nose of the heli is pointing towards the direction i want it to move to.

Likewise in inverted pirouetting, i prefer to give only back elevator, thus i'd give the input only when the nose of the heli is pointing towards the direction i want it to move to.

I've uploaded a video here which shows the input to keep the heli flat upright, inverted, and abit of moving around (mode 1).

Fast piro is suitable for use in piroflip/piro tictoc and such moves that requires the heli to stay in confined spot, as the gyroscopic effect gained from the piro rate would keep the heli more stable.

Slow piro requires both elevator & aileron inputs. Pretty much the same concept in moving it around, just give abit of elevator input when the nose of the heli is pointing towards the direction you want it to move to. The aileron input here is really to flatten the heli before it completes a full piroutte.

Slow piro is suitable for piro circle and any such move that requires larger 'air-space'.