Brushless motor Current rating.

[Djay Ahluwalia]

Timbo, 

 

The reason I started with a heavier AUW was to make sure I had an inbuilt safety factor for the aircraft, a motor designed to keep a 500 gm plane just off the ground would potentially be a good bet for a 350-400 gm model. But I guess it looks like with such projects most designs are built and run very close to optimum and not much give for worst case scenarios. Again, I would put this down to my inexperience.

 

Furthermore, perhaps this motor from the same website (altho a tad expansive), may prove to be 'marginally' better?

 

microREX 220-3-3200

 

 

This is from the flyware range.

Mind you my first flight test would be without the solar cells onboard and using a standard 2S LiPo battery.

 

Djay 

[Myron Beaumont]

Djay

You havn't explained about this "efficiency" factor .What is it a percentage of exactly . I wish you all the best but am a bit sceptical like I mentioned earlier .If you manage to crack it then I would like to be  one of the first to know just how it flies . It's the future isn't it ?

[John Privett]

Myron, I guess you're referring to the efficiency of the solar cells?

 

The sun is radiating energy,  which we 'see' mostly as heat and light.  At the surface of the earth the maximum energy we receive from the sun is about 1.4kW per square metre. 

 

Now if we could convert that to electricity with no losses in the conversion then Djay's solar cells, which have an area of 0.15625 square metres, could supply a little over 200W (0.15625 x 1400) to the motor. 

 

But solar cells are not very efficient. Djay's are claimed to be 15.5% efficient - so the maximum possible from Djay's cells is about 30W.  And even that would probably only be acheivable in the Sahara, at midday on a clear day.  So 25W, as mentioned earlier, is more realistic - possibly still slightly optimistic in the UK on anything but the brightest summer's day at noon.

[birdy]

Djay, just a thought:

 

I've no idea how much power a servo uses, but I wouldn't be surprised if it were a watt or so. 2 or 3 watts going to servos is a good 10% of your power, so it might be worth having a look for efficient ones... 

[Erfolg]

Solar cell aircraft and models are possible.

 

Even as far back as the 70s Fred Miiltky? of Graupner built and flew a model, powered by solar cells. I thought the Graupner or is it Robbe have a solar cell model in there current range. Could be wrong.

 

I have always been sceptical of the environmental merits of solar cells. In the past it was recognised that many noxious chemicals were generated during manufacture, also more energy was consumed during manufacture than they could generate during their useful life.

 

However, where the provision of a power supply is difficult to provide economically (however defined), yep they could be justified. Typically to provide remote a power supply in desert regions for telephone systems (as the original units produced by Bell Laboratories, a division of the so called Ma Bell) or road traffic signs in remote locations (is this a wise use of the worlds resources?).

 

Yep you can do it, but why?  A lipo does it better, in many ways! or even Methanol has its virtues, for modelling.

[Ed Anderson]

Any updates on this project?

[Tim Mackey]

I would ask that any more on this project be discusssd in another section please - this is for the very basics that beginners need.