Enough "lift" for helicopter flight

[TechnicJuan]

To all doubters:

Do a Google search for the term "Flight", and pick whatever online dictionary you like. Quote verbatim some text that refutes what I quoted from the Wikipedia definition of "flight". Those who claim that the model is not "flying" are basing their statements on their own opinions, not official definitions. Let's use scientific principles and be precise about exactly what "flight" is and is not. Thank you.

No need to Google anything because in my opinion, I have never seen a plane or helicopter flying through the sky being supported by a semi invisible string with a counterweight.

Once again, this thread is about Lego lifting Lego off of the ground unassisted. This model in question is not displaying that at all.

[DLuders]

The V-22 Osprey IS FLYING HORIZONTALLY because it meets this definition of "Flight" -- "Flight is the process by which an object moves either through an atmosphere (especially the air) or beyond it (as in the case of spaceflight) by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement." I dare people to refute that.

There is nothing in this definition (or any other, OFFICIAL definition of "Flight") that talks about needing to support 100% of its weight VERTICALLY while it is flying HORIZONTALLY. Look at the Wikipedia article again.

Edited December 28, 2011 by DLuders

[KEvron]

official definitions

i'm not sure there is such a thing as an official definition; there are only, as far as i know, definitions.

they'd've laughed orville and wilbur right outta kitty hawk....

KEvron

Edited December 28, 2011 by KEvron

[TechnicJuan]

No one is denying that this model isn't "Flying" after it is aided off of the ground by the counterweight. If not for the counterweight, this model would do absolutely nothing but sit on the ground and run out of battery power.

But the topic of this thread is "Enough Lift for Helicopter Flight" which is not being displayed here. It is not generating enough propulsive thrust to move itself off of the ground surface without being helped off of the ground by an outside source which is completely defeating the purpose of what this thread topic is about.

[DLuders]

Consider the crude Lego Helicopter in zcontube's

below. If it DID ACTUALLY RAISE off the ground, would the doubters out there consider it to be a REAL FLYING LEGO vehicle? Or, would they quibble and say that:

1) The electric cable tether is controlling the flight path.

2) The battery box needs to be part of the Helicopter and lift into the air too

3) The batteries in the NXT are not Lego-brand, and they need to be 100% Lego (like the Power Functions Rechargeable Battery Box provides)?

It's frustrating the people keep "moving the goalposts". I'm done with this topic.

[KEvron]

1) no. the cable does not contribute to the aerodynamics of the vehicle, nor does it have a positive effect on the the mass of the vehicle.

2) no, but others might say otherwise.

3) regardless of the resolution of this issue here, the sun will rise tomorrow. mercifully, no fate rests on the outcome.

KEvron

Edited December 28, 2011 by KEvron

[TechnicJuan]

It's frustrating the people keep "moving the goalposts". I'm done with this topic.

And it is equally frustrating to all of us that you keep tap dancing around this thread title's actual topic with Google searches and theories that have nothing to do with the issue at hand.

What has been displayed in every video that you (and the creator) have posted not only does not show an actual Lego build lifting off it's own weight, but consistently disproves itself in it's claims.

Edited December 28, 2011 by TechnicJuan

[KEvron]

really, is this a subject worthy of degeneration of community? we have a disagreement of technical terms, but it's a civil disagreement.

anger and frustration are perfectly valid emotions, but they're entirely wasted on the internet.

everybody, just keep it loose. if you're having a bad time on the internet, then you're doing it wrong.

KEvron

Edited December 28, 2011 by KEvron

[Blakbird]

Do a Google search for the term "Flight", and pick whatever online dictionary you like. Quote verbatim some text that refutes what I quoted from the Wikipedia definition of "flight". Those who claim that the model is not "flying" are basing their statements on their own opinions, not official definitions. Let's use scientific principles and be precise about exactly what "flight" is and is not. Thank you.

If you won't take the word of an aerospace engineer, then I guess there is not much more to say. Google and Wikipedia are very nice, but they are not technical references. For anyone really wishing to learn about Flight, I recommend the following.

• Anderson: Introduction to Flight
• Raymer: Aircraft Design, a Conceptual Approach
• Oates: Aerothermodynamics of Gas Turbine and Rocket Propulsion
• Filippone: Flight Performance of Fixed and Rotary Wing Aircraft
• Anderson: Hypersonic and High Temperature Gas Dynamics
• Pamadi: Performance, Stability, Dynamics, and Control of Airplanes
• Meyer: Introduction to Mathematical Fluid Dynamics

No one who studies these reference materials will still say this model is flying, and these are legitimate references. It is really cool though!

Getting back to the so-called "official definition" quoted, generating ANY lift or propulsive thrust can obviously not be considered flying or airboats (and even regular boats) could be said to fly. They both produce lift and thrust aero (or hydro) dynamically. But they don't fly because the lift needed to overcome the weight is not provided by the boat, but rather by buoyancy. In this case, the lift is principally provided by the counterweight. There is a distinction between heavier than air flight (airplanes and helicopters) and lighter than air flight (balloons and dirigibles), but in both cases the craft is lifted without assistance. The Wright brothers knew the definition of flight well enough. If what is shown in this video could be considered flight, someone would have beat them to it by at least a hundred years.

[KEvron]

moar flying lego!

someone would have beat them to it by at least a hundred years.

the brothers montgolfier did just that!

KEvron

Edited December 28, 2011 by KEvron

[Saberwing40k]

i think i may have a way of making a lego model fly. however, it does involve a couple of model rocket engines. one could make a large, flying wing model, with an nxt brick in it, and with 4 propellers, each driven by two xl power functions motors. in addition, you would need a control station made with a second nxt brick, or a laptop, or even a smartphone. (first two preffered, due to the ability to use joysticks.) on take off, you would ignite the rocket motors, then pull back on the stick, and take off normally. this method is good, because the only non lego parts are the rocket motors, and it would be a fully flyable lego plane.

now, before you shoot me down, is a glider flying ? is a cargo plane that uses RATO flying ? this things is basically a little bit of both. now, who's crazy enough to try it?

[Alasdair Ryan]

You should try it,how ever i far that it would just drop after the rocket engines.

[Blakbird]

i think i may have a way of making a lego model fly. however, it does involve a couple of model rocket engines. one could make a large, flying wing model, with an nxt brick in it, and with 4 propellers, each driven by two xl power functions motors. in addition, you would need a control station made with a second nxt brick, or a laptop, or even a smartphone. (first two preffered, due to the ability to use joysticks.) on take off, you would ignite the rocket motors, then pull back on the stick, and take off normally. this method is good, because the only non lego parts are the rocket motors, and it would be a fully flyable lego plane.

now, before you shoot me down, is a glider flying ? is a cargo plane that uses RATO flying ? this things is basically a little bit of both. now, who's crazy enough to try it?

Sure, gliders and RATO count. The energy to take off comes from somewhere else, but once airborne the model supports and controls itself. LEGO will still be a problem with lift/weight ratio though. The model will be VERY heavy compared to wing area, so the glide slope will be approximately -1. ;-) Does falling straight down count as flying? If so a couple of my models have flown when I knocked them off the table!

[KEvron]

well, if anyone ever does manage to realize a genuine aircraft in lego, it'll undoubtedly be some kind of rudimentary helicopter rather than a plane. airfoil lift is a lot trickier than thrust, especially when lego has already provided several prop designs. and, as DLuders hinted in his penultimate comment, it won't bear it's own power supply.

idea for glider: frame it in abs, skin it in lego sails.

....or in these. hey, if it's got a part number, it's a lego element.

KEvron

[allanp]

Problem is that a helicopter also relies on aerofoil lift. To create that shape in lego effectively is not really possible. You can make something that is sort of the right shape, but any deviation, especially things like studs and plate edges, will pretty much kill whatever lift is created. Even dirt on a propeller will greatly reduce it's efficientcy. I think the best chance is to make a light as possible skeletal structure using rigid flex tubes to make the aerofoil shapes, then covereing it tightly and seemlessly with tissue and doping it.

http://www.instructables.com/id/Covering-a-model-airplane-in-Tissue/

Of couse this isn't much good for helicopter flight as the topic suggests, but I think that would be even harder that flying planes.

Edited December 31, 2011 by allanp

[Ape Fight]

A Lego glider is definately possible - I've seen one on the net somewhere (sorry, no link) that used those large blue flat plates from (I think) the old Technic space sets that ran for about a year.

It glided beautifully, but I guess only because it used the least Lego-y Lego parts possible.

Still, it's been proven to be possible, although it it is gliding rather than sustained flight.

[andythenorth]

Would a lego vehicle with a gas envelope (balloon) be flying?

[bb15080]

Would a lego vehicle with a gas envelope (balloon) be flying?

[DanRZ]

Hello i think it is a very interesting challenge.

I fly RC helicopters and know very well what produces lift.

You need to make blades with a particular profile.

The real problem is to stay "light" as much as possible and "rigid".

I think i will try to make a blade on LDD ...

The blade shape of lego technic is quite good but it is not wide enough.

The next problem will be the rotor in the boom, it should also generate tranversal lift to stabilize the helicopter.

Whitout rear rotor it will twist around the main rotor due to the counter torque generated by the main blades.

One solution is to make a "coaxial" helicopter with two rotor "counter" rotating, like those helicopters mini toys.

Or with two separated rotors always "counter" rotating like the well known shinook helicopter.

The last problem will be to move the helicopter with "cyclic" commands, that would be a really hard work with lego.

Yous should make what we call a "swashplate" to command the "pitch" of the blades.

But a double counter rotating rotor helicopter should almost "lift off ground" ... i think its possible.

With a rotor sized as the 8068 box ( Rescue helicopter ), the main rotor should run at almost 3000 rpm to generate lift,

that is really fast for a lego structure ...

[DanRZ]

Somebody have already done the swashplate : http://www.eurobricks.com/forum/index.php?showtopic=64073&view=findpost&p=1156736

Edited December 31, 2011 by DanRZ

[KEvron]

a helicopter also relies on aerofoil lift

for rudimentary flight, the aerodynamics of the props are the only concern.

but that prompts the question: just how aerodynamically viable are lego props? we could pay all the attention in the world to the design of an airfoil, but it won't mean diddly if lego's props are more show than blow.

Somebody

the very second i saw it, i recognized that as the work of leo dorst. leo is the godfather of the lego clock. he's the davinci of lego!

KEvron

Edited December 31, 2011 by KEvron

[Saberwing40k]

okay, so we need lego rotors. from the look of things the new for 2012 helicopter has well shaped rotors, and a swashplate. this may just be possible, as long as those rotors are new parts and not brick built.

[Alasdair Ryan]

This one not good?

Looking at it, it does seem a bit on the short side.

[locoworks]

worked out how it could be done with true flight taking place, i.e. NO tethers, counter weights, helium balloons, etc etc. you ask NASA to take it into the upper atmosphere/space to a point where there is very little gravity acting on the lego, just enough to let it fall slowly. the underpowered lego motors would then be able to produce lift greater than the gravity effect on the lego and voila. down here on earth though, wont happen unless lego go into really powerfull brushless motors in their kits, at whioch point the rest of the plastic won't take the strain.

[3nslav3]

I don't think that will work,

the air is probably to thin at such high altitude (i'm not an expert tho but it seems logical)

unless you to to such high altitudes and fly the lego model in a compressed air tank

Edited January 1, 2012 by 3nslav3