| Unmanned Aircraft analysis | - UAV Analysis |
|
Above: the InView unmanned aircraft: designed and built by the staff at Barnard Microsystems Limited. We have derived data from the open literature for the following UA, and used our UA Analysis Utility to check the consistency and reality of the data. Interestingly, we have found some glaring inconsistencies in the published UA data, particularly in respect of the suggested range.
After checking the data consistency, we derived relationships between UAV parameters based on the above UAVs. |
|||||||||||||||||||||||
If you plan to use existing data as a basis for trend analysis, it is important to check the consistency of the data first. In particular, the military are often more interested in endurance time, and for them the UAV range is often less important and governed by issues such as Line of Sight (LOS) or limitations on the range of their Command and Control radio links. So, more often than not, the quoted UAV range is far less than the true range cabability of the UAV in the absence of radio link issues. Note that we have converted a Microsoft EXCEL spreadsheet to an HTML script using the SpreadsheetConverter software, and have incorporated the resultant HTML script in this web page. Consequently, depending on the security setting on your computer, you might be asked whether you would like to allow your computer to run the following HTML script. I have noticed that the UAV Analysis Utility can become corrupted. If you find it is not working, please drop me an email and I will upload a working copy of the utility. My email address is:
In this section we discuss the basis for the calculations of the various UA parameters from input data consisting of:
Length = WingSpan / 1.775 = [m]
For a flight at constant speed, we have assumed the power required to keep the plane moving is directly proportional to the total weight of the plane, which decreases in a non-linear manner with time as the fuel is used up. The weight of the plane at a distance = x is given by W(x) = W to * exp( - x / D ), where W to is the take-off weight of the plane, and D is a figure-of-merit for the plane we call the " characteristic distance" . Through a simple integration, it can be shown that: D = R / ln (W to / W nf ) where R is the range, W to is the take off weight and W nf is the weight of the of the plane with no fuel on board. For simplicity, it is assumed that at the end of the UAV flying a distance = R, there is no fuel left on the UAV.
Endurance = Range / EnduranceSpeed = [hours]
For a four stroke engine, Pout = 0.073 * x + 0.031 for Pout in kWatts, where x is the engine capacity in cc. The engine capacity = CAP is given by:
payload weight = Wpl = Wto - Waf - Wf - Weng
|
|||||||||||||||||||||||
