Please see the video below for a description of my fuel cell controller (so far) for a remote controlled plane. A fuel cell provides much greater energy density than a battery, so for long endurance it is far superior (hours). Hopefully, with a bit of refinement I'll have the system flying in my SkyWalker X8 in the spring.
Feel free to comment, I look forward to sparking some interest!
Simon
Comments
Glad you're sharing my excitement!
I shall keep you all posted!
I can not express enough how much this technology excites me. Advances in battery technology is the one of the biggest limiting factors facing the UAV community, making fuel cell tech very interesting.
Specifically the fact that it is possible to generate the 'fuel' at home using a simple process. Personally, I always thought this type of technology was out of reach because it is so dangerous to store hydrogen, which is why I find the HydroStik very interesting. Definitely staying tuned for this one...
The calculations are a bit wishy washy, but at 100W the numbers say a single HydroStik would last 26hrs. The fuel cell is probably only 40% efficient on a good day, so call it 10hrs. The HydroStiks arent capable of discharging hydrogen from their storage quick enough for the fuel cell to consume, so you would need a few in parallel (no idea how many yet) so multiply that 10hrs up by the number needed. Add an engineering fudge factor in and I'd maybe expect 10hrs from 3-4 sticks, anything else is a bonus.
Really wishy washy at the moment though until I do the endurance test after Xmas so don't take these numbers too seriously!
@Simon Thanks, I remember now you store it in gaseous state, so 100g is ridiculous :) I'm just trying to get a mental handle on what to expect. Do you have a rough estimate in your head re. maximum flight time for the X8?
Hi Jethro,
I will be looking into supercaps but initially I am going to use a LiPo for the hybrid. I did a quick calculation for stuff available off the shelf, and an £18 LiPo would give me full power for 44secs. The equivalent weight of supercaps would cost £100 and only give me 14secs. I'm not going to discount it though, but supercaps aren't really an energy storage device, just a power smoothing unit. This would be useful for fluctuations in flight to save cycles on the lipo though.
Hein, thanks for your comments. It's not as simple as you suggest. Firstly 100g H2 is over 1000 litres, which I couldn't carry. The energy density of the hydrogen fuel is higher than LiPos, for short flights the whole system is not as good as a LiPo but for long endurance, the system weight plus fuel is considerably lighter than a load of LiPos. I can't quantify the numbers until I have run some more tests, but I'll keep everyone posted.
Wow, very interesting and excellent work!
100W seems ideal for cruising, at least for a Skywalker or your X8.
If you say a H fuel cell's energy density is higher than LiPo, does that include the cell, controller, tank, etc? It seems there is 1.3kg weight before installing the H tank. 1.3kg of LiPo will give me 2 hours of flight. What flight time are you expecting based on the X8, per say 100g of H?
That's the part I was looking for :)
I know precious little about it so I find this very interesting. Will follow your progress on it.
This is a very interesting technology Simon and I am keen to hear more. Hydrogen-oxygen is certainly an ideal fuel, with energy densities far greater than any batteries, the problem is that there is a limited discharge rate and the fact that fuel cell systems are heavy.
What would be interesting is a combination of fuel cells and ultra-capacitors: http://cleantechnica.com/2013/10/14/lithium-ion-batteries-vs-fuel-c...
This is also a fantastic read What Are Batteries, Fuel Cells, and Supercapacitors?: http://pubs.acs.org/doi/pdf/10.1021/cr020730k
Very good work being done. I'll keep an eye on progress.
Yep that's a good market for it certainly! My cruise power at the moment is between 90-130W depending on how I fly and the weather conditions.
In terms of how it links in hybrid, just do a quick google search for the wiki on hybrid powertrains, it explains it well there. Piling more LiPos will be more weight efficient to a point, but then it will become too heavy. Hydrogen has a far greater energy density than a LiPo, so if you are wanting to fly for 10 hours say, hydrogen will be ok, LiPo too heavy.
Quantities needed aren't huge. You can buy it but it isn't too easy to get hold of because it's a flammable gas which is hard to store with no residential uses. Not too dissimilar to propane 50 odd years ago but now we all have that for the BBQ and my car is powered by it!
I must highlight that this is research, so on the technology readiness level (TRL) it is quite low, so don't expect it to work well or be in the shops tomorrow. We are certainly moving forwards rapidly though, and I'll keep posting to let you know how it's coming along!
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