Cambridge solar farm construction filmed by drone

[Johny B Good]

Only about as much as I want to buy one of those "Toy" helicopters with their daft contra-rotating blades. The last time I played with a tiny IR controlled Lipo powered 'model' toy helicopter, it was one with the classic single rotor (albeit with the balance weights stability assist add-on) bought in AldiLidl nearly a decade back.

In recent years, not even the model shops sell proper model RC helicopters any more, they're all these abominable contra-rotating blade contraptions, even with the more sizeable models costing a hundred quid and up (I realise this is still cheap compared to the proper scale flying models used by serious RC hobbyists).

I was quite surprised and dismayed at seeing a model shop selling toy helicopters to the total exclusion of RC model helicopters when I last popped into such an establishment a few years ago. Perhaps I was just looking in Toy/Model chain stores where the more specialist hobbyist interests had been dropped from their remit in favour of the 'consumer' market.

[dennis]

Maybe you just look in toy shops?

Not really a true representation though as it can do more than a real helicopter can.

[Nightjar]

The only JFK speech I can recall is when he claimed to be a doughnut.

[Tim Streater]

Not even the one where he talked about putting a man on the moon and getting him back before the end of this decade?

[Huge]

Yes, but what was "the other thing"?

[Vir Campestris]

On 08/03/2015 11:36, Nightjar The only JFK speech I can recall is when he claimed to be a doughnut.

I'm told that the residents of Berlin do indeed claim to be Berliners. (Ish bin ein... with their local pronunciation... not that I'm an expert)

Though I too was amused the first time I saw some for sale ;)

Andy

[Johny B Good]

My question also as per the above paragraph you snipped out.

That's simply a question of scaling effects as well as making use of outrageous power to weight ratios impossible to apply in 'full size' helicopter designs.

The 3D stunt flight movies are very reminiscent of dragonfly flight dynamics where these very agile and strong insect flyers can do 4G linear accelerations and 9G in turns. Again, it's all down to scaling effects and I rather doubt their ancient giant ancestors with 700mm wing spans made possible by the prehistoric and rather incendiary 40% oxygen rich atmosphere that prevailed in the carboniferous era could even approach these levels of acceleration.

Those RC helicopter models have a level of 'over engineering' and power to weight ratio that simply can't be scaled up to full sized models so it's no surprise that they can outdo the 'real thing' when it comes to aerobatic stunt flying.

[Johny B Good]

Hmmn, that's an interesting non sequitur.

[The Natural Philosopher]

Umm. No. It not power to weight that changes with a model - in fact its surprisingly consistent between models and full size aircraft.

What changes is strength to weight, as the sort of G forces that the model encounters to do what it does would tear the full size to pieces.

[The Other Mike]

First one looks like more like a hover mower. Can't even start to think what is happening on the controls to make it perform like that.

[Johny B Good]

That's a slight misquote and actually from his Address at Rice University on the Nation's Space Effort in September 1962, _not_ his inaugral speech as I had misremembered - apologies for the confusion.

What he actually said was,

"We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard..."

I was simply suggesting that building a solar power farm on the _northern_facing_slope_ of a hill could be regarded as just another one of those "other things" mentioned in JFK's Address at Rice University on the Nation's Space Effort (at least as far as a northern hemisphere location is concerned).

[Nightjar]

He should really have said 'Ich bin Berliner', not 'Ich bin ein Berliner'. To many Germans (although not Berliners) ein Berliner is the doughnut.

Last time I was in Berlin they were being sold with 'Ich bin ein Berliner' labels on them.

[Nightjar]

Only now you mention it. I have wondered whether that would have been such an important target if he had not been assassinated.

[Vir Campestris]

I'm surprised by that. I've seen lots of model prop aircraft that can climb vertically under full power. Not many full scale ones can. Perhaps I've only seen the high powered demonstration ones.

But that doesn't surprise me at all! Square-cube law.

Andy.

[Johny B Good]

That's all part and parcel of the effects of altering scale. To take a very simple example of what you're talking about, consider the roll rate of a flying fixed wing RC model.

At the smaller dimensions, the model can roll at much faster rpms without generating destructive G forces on the structure. Attempting the same rpm roll rate in a full scale version would literally cause the wings to to fly off due the inreased G forces involved at this scale.

Even if you tried to strengthen the structure you'll still end up with the same result since the only means of adding strength is to add more material which adds mass in the same proportion which nullifies the gain in structural strength.

In the days before CGI solved the problem of depicting air and sea battle scenes in epic movies, largish scale models would be used (the larger the better) and filmed at high frame rates inversely scaled to match the linear scale used, along with much brighter lighting to allow very small lens aperture settings to be used to provide a scaled depth of field to remove the 'toy effect' from the captured footage.

For air battle scenes this was quite effective but the surface tension effects of water in naval battle scenes could defeat the simulation due to the effect it had on droplet size and wetting behaviour on small scale structures (hence the desire to use as large a scale of model as the budget would allow).

I don't know whether any attempts at reducing the surface tension of the water were used (additives to the water or a different fluid with almost no surface tension) but that would be _my_ next consideration in trying to retain 'realistic' behaviour of the model, assuming any side effects or additional hazards were managable enough to make this possible (foaming due to such additives or flamability/health hazards of hydrocarbon based low surface tension substitutes for the water).

Whilst the look of a small scale replica can match that of the original, the inertial dynamics of such 'working' models won't match that of the original, appearing to be far more responsive than 'The Real Thing' could ever be. In the case of those stunt helicopters, impressively so.

[Johny B Good]

Apparently it's down to the use of 3 axis gyro sensors in the RC module (occasionally refered to as 6 axis gyros when accelerometer functions are added into the mix).

As to how this gets round the obvious issue of control reversal effects when the attitude relative to the remote operator changes through 180 degrees (pointing away/toward , traversing left to right/right to left and inverted/non-inverted relative to the operator), I just can't imagine. I guess it would need an experienced operator willing to spare their valuable time to explain the process to fathom this one out. Don't ask me btw, I had enough trouble with toy RC cars! :-(

[Johny B Good]

Actually, now that others have explained your reference, not such a non sequitur after all. I have to say, it sounds rather like a 'nugget of information' the QI Elves would have quite happily used in setting QI questions for Steve to fire at the panel.

[The Natural Philosopher]

It doesn't. That's what training and practivce are for.

I guess it would need an experienced

[dennis]

Its usually the operator that does that. Having said that some of the models come with preprogrammed stunts that only require the flick of a switch. Its would be a short step to make them user programmable. You can program flights into the DJI phantom leaving you to concentrate on camera control.

[The Other Mike]

I thought it an oblique reference to the grassy knoll but I have no idea which way it faces, I wasn't there, I was in the Book Depositary at the time cleaning up.