The Technic Challenge Competition May: Helicopter

[Blakbird]

A technic question : I'm going to build a copter with two main rotor. Do these rotors need the collective pitch in real helicopters?

Excuse me for this maybe stupid question .

That's actually a very good question. Because of Newton's 3rd law (simplified: for every action there is an equal and opposite reaction) when the main rotor turns one direction, the helicopter itself wants to turn the opposite direction. In a conventional helicopter, a tail rotor faces to the side and counteracts this torque. On a coaxial helicopter (only a few exist in real life, mostly Russian), two main rotors on the same axis turn in opposite directions, balancing the torque. Because there is no tail rotor, these coaxial rotors need to be synchronized to turn with the same speed (or more specifically torque, or even more specifically angular momentum) so the helicopter can remain pointed in the same direction. Something like collective, which changes the pitch of the rotor blades, must also be balanced, therefore both rotors need collective. Squeezing in a pair of coaxial swashplates along with cyclic is quite an engineering feat which is one of the reasons there are so few of them. On this picture of a coaxial helicopter, you can clearly see the collective mechanism on both rotors.

Incidentally, there are a lot of R/C coaxial helicopters (I have a couple of them), but most of them do not have collective pitch; rather they only have cyclic. They control power by increasing the speed of the motor. Since they use only cyclic, usually only the lower rotor head has a swashplate.

Maybe this detail of the 852 helicopter from 1977 (!!!) is even more impressive!

Source: Blakbirds Technicopedia on Lego 852

That model is the only official Technic model with a swashplate of any kind, and is ironically the most realistic helicopter despite being the oldest.

[DLuders]

On the Lego Technic Designers Blog, Blakbird (Eric Albrecht) wrote a nice article on Helicopters. He includes a nice chart on the various Lego Technic helicopter sets.

Edited May 11, 2011 by DLuders

[drakmin]

What is the deadline of this competition? 17th of May?

[DLuders]

@ Drakmin: Real faint on the right-center of this Lego Technic Challenge webpage, it says "ENDS Friday 19th of April by 23:59 CET [Central European Time]." Obviously, the Challenge organizers did not update the page from the previous month (again). If one looks at the verbage on this webpage, it mentions that judging will start "On the 18th of May...." So, I agree with you that the entries are due by midnight May 17th CET.

[DLuders]

Louskam posted 8 pictures of his tilt-rotor "Hornet Delta 6" "Model for Lego Technic Challenge May -futuristic helicopter" on his Brickshelf gallery:

Edited May 14, 2011 by DLuders

[drakmin]

Here's my entry. Click for larger image. Check my Brickshelf when the Banshee folder becomes public, thanks!

Drakmin's Brickshelf

[allanp]

That looks really cool, seems to be alot of avatar inspired helis lately. For a moment I thought your x-wing was the entry

[DLuders]

Ten finalists have been selected by the Lego Technic Challenge judges -- vote here.

[RohanBeckett]

Gah... they need to fix the voting page, so you can zoom in on the MOC's

how am I supposed to vote, when all I can see are 200x150pixel thumbnails?

at least they all have the logo printout, and actually look 'authenticly' built by kids/teenagers! :)

RB

[JunkstyleGio]

RohanBecket is right: The logo seems to exclude those darn cheaters...

[grohl]

//

Edited May 20, 2011 by grohl

[efferman]

It is hard to vote for a Helicopter that could never fly. so i voted for the one who looks good: The hornet 6

[AndyC]

It's good to see the genuine entries getting through this time, let's hope to see more great models from now on.

Edited May 21, 2011 by AndyC

[drakmin]

I wonder why my Banshee didn't make it to the voting :|

[JunkstyleGio]

@ Drakmin: Maybe because you are a AFOL?

[drakmin]

@ Drakmin: Maybe because you are a AFOL?

Oh was there an age limit (facepalm here). I thought I read the rules ;D

[legolijntje]

Oh was there an age limit (facepalm here). I thought I read the rules ;D

No, there is no age limit, but they seperate the children from the adults nad tey choose 1 adult winner by themself

Take a looke at the blogpost HERE (the last one).

Edited May 21, 2011 by legolijntje

[GuiliuG]

at least they all have the logo printout, and actually look 'authenticly' built by kids/teenagers! :)

I do not thorougly understand this sentence : when I see Makorol's models, they are more beautiful than other adult's creation.

[DLuders]

mrTECHNICER made

of his Lego Technic Futuristic Helicopter entry into the May 2011 Lego Technic Challenge. It is his "first helicopter. It's got motorized outriggers synchronized with lights, manually tilted propellers from the cabin and underside catch."

[vmln8r]

Helipak by vmln8r, on Flickr

Lightweight single-seat helicopter. It features a single motor, which drives a pair of contra-rotating, coaxial propellers. It uses only parts from Technic sets.

Here's the real thing - wonderful isn't it?

This took less than an hour to put together, but much longer to photograph and edit. I took a picture of the model on a stand, then a picture with just the background, combined them and edited out the stand. The problem is that the tone of the sky in two pictures differ, which makes the end result a bit yucky. Ordinarily I'd draw neatly around the edges, but with the spinning propellers and everything, I quickly hacked roughly around the edges and called it a day. If anyone knows a better way to do this, please let me know.

[drakmin]

VMLN8R: If you use Photoshop, try altering the sky layers "blending mode". Usually one of the blending modes gives a desired result and needs only a small amount of tweaking. Blending mode is the small drop down menu right below the Layers menu text.

[vmln8r]

Thanks drakmin - I did try using layers, none worked well, even after using [edit > fade > luminosity]. It was only the propellers that caused a problem. Rushing the pictures and taking them in poor light probably didn't help either.

[drakmin]

Thanks drakmin - I did try using layers, none worked well, even after using [edit > fade > luminosity]. It was only the propellers that caused a problem. Rushing the pictures and taking them in poor light probably didn't help either.

Place sky on bottom in the layer stack. Add you copter on top of it. Cut propeller away from the copter layer and add it as a third layer on top of everything. Select the propeller layer, change this layers blending mode to darken or overlay for example, should work.

Edited May 23, 2011 by drakmin

[jovel]

That's a nice compact model wtih a great presentation!

To prevent your image from cheaters ( if there will be competition next year again ), I would consider to remove the technic challenge logo or make it blury.

Edited May 25, 2011 by jovel

[vmln8r]

Thanks again drakmin, I will certainly try that out.

That's a nice compact model wtih a great presentation!

To prevent your image from cheaters ( if there will be competition next year again ), I would consider to remove the technic challenge logo or make it blury.

Thanks (and for your comment on the Batpod). I wouldn't mind all that much if someone thought this was worthy of plagiarising - but when I get around to retouching this image, the logo will likely disappear.