Sandra Almeida (Cassiebsg) is a Portuguese AFOL, living in Denmark. As could it not be, she participated in the '2011 LEGOWORLD Copenhagen, DK' and sent us this nice video (among a thousand others...) from the LEGO Technic/MINDSTORMS Zeeplin flying around.
There were a few similar models hovering...
I've seen two different models, as you can realize from the video and photo below.
I tried my self a similar contraption a few months ago and tested it at the last Hispabrick, in Barcelona. The new 89509 blades from LEGO Education 9688, Renewable Energey Add-on Set were quite promising... However I didn't had the idea to use such helium balloons and of course it didn't lift off!...
But it was quite funny to observe at least a very small vertical impulsion and getting the proto-heli spinning around.
Definitely far from the required to defeat all the weight from the structure, motors and propellers. Even hanging the tethered batteries by hand (video still to produce...).
Some observations though...
- Higher gear rations produce more rotational speed, hence more impulsion, but the inertia is also too high and the current drawn makes the PF rechargeable battery to cut-off after a few seconds or to slow down considerably, to be more precise.
- Propellers with 3 or 4 blades also perform better, because of exactly the same effect (high speed RC motors were used, like those in the air powered car from Barman).
- A tail rotor is required to prevent the heli to spin, but adds a lot of weight and zero contribution to vertical impulsion.
To have it balanced without a tail rotor, we would need the same blades but with the opposite pitch, in order to build counter-rotating propellers (LEGO, please!...).
It is something possible to achieve with the actual blades and some angled connectors, but unfortunately this means extra weight, less performance and a too complicated design.
Not yet time of having a model made entirely of LEGO, able to fly autonomously.
Marc-Andre Bazergui (bazmarc) [1, 2], Canadian, member of QUELUG, member of MCP4 group and known for his MINDSTORMS models, left us a comment with another video he produced, featuring the Zeppelin (Blimp) flying over, at LW2011DK.
The video also features a small interview with the authors (Kenneth Madsen and Lasse Lauesen) where they explain the basics of their project and where we got to know the software was made in Java, there is an NXT made remote control, to flight the blimp and one on-board camera which produced fantastic aerial images from the event.
From Marc's comments we also learned that "the NXT moves on the rail only to adjust the initial balance (if one balloon has more helium, move NXT to counterbalance etc..) Also very important is that to make the RC motor efficient, Lasse had to design his own motor controller".
See the magnificent video bellow and look later for further info about this project, at the authors website www.brickit.dk.
Last Update: 2011.Mar.01 08:30 CET