New Customers Requirements for my next Helicopter UAV. It hurts.

DennisFetters

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No horizontal stab needed.
And, they want it in two years.....

1. Maximum Airspeed - 145 knots

2. Endurance - 4 hour with 500 kg payload with full fuel

3. Ceiling - 20000 feet

4. Autonomy - fully autonomous takeoff, waypoint navigation and landing

5. Datalink range - 200 km (just electronics)

6. Operating Temperature - -40 to +71 C degree

7. Wind - Up to 30 knot wind (That's hard for even a manned helicopter)

Question;
How do I build something that can hold up to an ambient outside temperature of 71C? Can it be done? Anyone with any experience of a C20 turbine operating in that condition?

I estimated vehicle empty weight at; 700kg (or less)

I calculate the fuel load at 380 continuous shaft HP: 530kg

Vehicle max gross weight: 1730kg

All on the edge, but within the numbers...... But I would have to move to East Europe.
 
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71 C is about 160 F, which is is about 30F hotter than the warmest weather ever recorded on planet earth. Are they planning to fly it through forest fires?
 
Sounds like they want to collect close proximity video durinq nuclear weapons tests??????
 
Most unmanned aircraft can save the weight of an air conditioner but this one will need a high power blast freezer to keep its innards from frying.
 
71 C is about 160 F, which is is about 30F hotter than the warmest weather ever recorded on planet earth. Are they planning to fly it through forest fires?

They are probably concerned with ground temperature. Presumably the air right above a sunny spot is not a whole lot different in temperature. And if you land at a hot spot and want to take off again, it will need the performance.

Also according Wikipedia, a ground temp of 93.9 °C was recorded in Death Valley. --So, 70 °C doesn't seem totally out of wack. --Now, if they want 70 °C at 20,000 feet, its over specification.
 
They are probably concerned with ground temperature. Presumably the air right above a sunny spot is not a whole lot different in temperature. And if you land at a hot spot and want to take off again, it will need the performance.

Also according Wikipedia, a ground temp of 93.9 °C was recorded in Death Valley. --So, 70 °C doesn't seem totally out of wack. --Now, if they want 70 °C at 20,000 feet, its over specification.

Surface temperatures are of concern at race tracks, with hot asphalt in the sun influencing tire performance, but until helicopters start ingesting dirt instead of air, it's not much of a realistic worry. Performance specs for aircraft always rely upon air pressure and temperature, and no manual I have ever seen for any aircraft shows any data at all for temps that anywhere near that high. That same Wikipedia quotes experts who say that the hottest credible Death Valley weather recording (not dirt temperature) is only 53.9 C / 129 F. 70 C air isn't credible to me absent flames below you.
 
I'm finding out more about the requirements. This is a big company that builds military equipment. They are run by a big bureaucracy committee that dreams up what they need or want. Money is not the great concern to these guys, but they want a robust product that looks good for their company.

These guys don't know much or anything about helicopters. They just sit around and dream up every possible scenario any one customer may need and want a UAV helicopter that will fit 100% of the customers and 100% of the customers needs. They don't realize the expense and challenge that would be to make one UAV helicopter do all that.

In fact, maybe one customer out of 500 may need the UAV to fly somewhere 71c, and then maybe only do that one time ever for 10 minutes for the duration of that vehicles life. So some chump on the board wants all the vehicles to do that, and another chump wants it to scream along at 20,000ft, and another chump wants enough fuel to fly a 500kg payload 4 hours... and so on. Once they all get their way, a good idea turns into a monster like the American space shuttle did.

After a face to face they become better educated and realize they are over stretching the real needs of such a vehicle, and it is much easier to have variants of the same design modified to meet special mission conditions.
 
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