1 / 55

Design of UAV Systems

Design of UAV Systems. UAV System Design. Objectives. Lesson objective - to complete the example UAV System Design. Expectations - You will better understand how to wrap up a pre-concept design project.  2002 LM Corporation. 26-1. Design of UAV Systems. UAV System Design.

jessica-mitchell
Download Presentation

Design of UAV Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Design of UAV Systems UAV System Design Objectives Lesson objective - to complete the example UAV System Design Expectations - You will better understand how to wrap up a pre-concept design project  2002 LM Corporation 26-1

  2. Design of UAV Systems UAV System Design  2002 LM Corporation Review - surveillance UAV • Predator follow-on type • Land based with 3000 foot paved runway • - Mission : provide continuous day/night/all weather, near real time, monitoring of 200 x 200 nm area • - Basing : within 100 nm of surveillance area • Able to resolve range of 1 sqm moving targets to 10m, and transmit ground moving target (GMT) data to base in 2 minutes • - Able to provide positive identification of selected 0.5m x 0.5 m ground resolved distance (GRD or “resolution”) targets within 30 minutes of detection • - Ignore survivability effects • Minimum required trades • - Speed • - Operating altitude • - Time on station • All weather (SAR) vs. under weather (EO/IR) • Size and numbers req’d 26-2

  3. Design of UAV Systems Surveillance area Loiter location? UAV System Design  2002 LM Corporation Surveillance UAV 200 nm 200 nm 100 nm 26-3

  4. Design of UAV Systems Ceiling and visibility (customer defined) • Percent occurrence • 50% • 30% • 15% • 05% Clear day, unrestricted 10Kft ceiling, 10 nm 5Kft ceiling, 5 nm 1Kft ceiling, 1nm Weather definition (derived) • 60% • 30% • 10% Good weather Bad weather Unflyable weather UAV System Design  2002 LM Corporation Requirement refinement • Defined requirements (from the customer) • Continuous day/night/all weather surveillance of 200nm x 200nm operations area 100 nm from base • Detect 1 sqm moving targets (goal = 100%, threshold = 80%) and transmit 10m resolution GMTI data in 2 min. • Provide 0.5 m resolution visual image of spot targets (goal = 100%, threshold = 80%) in 15 min. • Operate from base with 3000ft paved runway 26-4

  5. Design of UAV Systems 158 nm 100 nm 200 nm x 200 nm UAV System Design  2002 LM Corporation Initial system baseline • Five medium UAVs, four provide wide area search, a fifth provides positive target identification • SAR range required (95km) • Only one UAV responds to target ID requests • No need to switch roles, simplifies ConOps • No need for frequent climbs and descents • Communications relay req’d, • distance = 158 - 212 nm • Speed requirement = 282 kts • For target identification role • Operating altitudes different • for each role • We will study other • options as trades • Payload requirement : • 707 lbm @ 26.55 cuft • (including comm relay) 17 Kft 17 Kft 10 Kft 17 Kft 17 Kft 26-5

  6. Design of UAV Systems UAV System Design  2002 LM Corporation Initial derived requirements • Derived requirements (from our assumptions or studies) • System element • Maintain continuous WAS/GMTI coverage at all times • One target ID assignment per hour • Uniform area distribution of targets • Communications LOS range to airborne relay = 158 nm • LOS range from relay to surveillance UAV = 212 nm • Air vehicle element • Day/night/all weather operations, 90% availability • Turboprop power • Takeoff and land from 3000 ft paved runway • Cruise/loiter altitudes = 10 – 17Kft • Loiter location = 158 nm (min) – 255 nm (max) • Loiter pattern – 2 minute turn • Dash speed =141 nm out and back @ 280 kts • Dash altitude  10 Kft 26-6

  7. Design of UAV Systems UAV System Design  2002 LM Corporation Initial derived requirements • Air vehicle element (cont’d) • Payload weight and volume = 707 lbm @ 26.55 cuft • Payload power required = 4300 W • 18 hour WAS capability • Cruise L/D  24.5 • Loiter L/D  25.6 • Cruise TSFC  0.326 • Loiter TSFC  0.31 • T0/W0 = 0.121 • W0/Sref = 40 psf • Bhp0/Weng  2.25 • Leng/Deng  2.5 • Engine density  22 pcf • Clto  1.5 • Wlg/W0  0.05 • etc. 26-7

  8. Design of UAV Systems UAV System Design  2002 LM Corporation Initial derived requirements • Payload element • Installed weight/volume/power  707 lbm/26.55 cuft/4300W • SAR/GMTI • Range/FOR /resolution/speed = 95 km/45/1 m/2 mps • Uninstalled weight/volume/power  350 lbm/8 cuft/3000W • EO/IR • Type/range/resolution = Turret/13.3 km/0.5 m • Uninstalled weight/volume/power  100 lbm/1 cuft/700W • Communications • Range/type = 212nm/air vehicle and payload C2I • Uninstalled weight/volume/power  57 lbm/5.9 cuft/300W • Range/type = 158nm/communication relay • Uninstalled weight/volume/power  57 lbm/5.9 cuft/300W • Control Station element • Waypoint/flight path control • 6 control consoles [air vehicle/EO/IR (2), SAR (1), C3I (1), product process/dissemination(1), launch and recovery(1)] plus provision for back-up/jump seat (1) • Support element • To be determined 26-8

  9. Design of UAV Systems Range center Target width corner mid-side UAV System Design  2002 LM Corporation WAS requirement resolution • Because our weather criteria defines 10% of the days as unflyable, we can no longer use 80% target area coverage to meet the 80% threshold requirement • Area coverage will have to increase to 89% • WAS SAR range/target width required goes up to 0.55 nm or WAS range = 55nm (102 Km) 26-9

  10. Design of UAV Systems UAV System Design  2002 LM Corporation SAR sizing considerations • A number of factors affect SAR range (minimum and maximum) and resolution • Power (how much RF energy is reflected from the target) • Even though transmitted power required vs. radar range is typically expressed as a 4th power relationship, our parametric data (based on total input power required) shows a nominal linear relationship • Geometry (minimum and maximum depression angles) • Absolute minimum angle defined by the radar horizon • Typical minimum “look down” angle about 5 degrees • Typical maximum “look down” angle about 60 degrees • Dwell time (how long energy stays on the target) • Function of platform speed and/or antennae pointing • Signal processing time • To keep things simple, we resize using only the range-power parametric and geometry (ignoring curvature) 26-10

  11. Design of UAV Systems 5 deg 44.7 deg 20.8 deg 5.6 deg Min range (from spreadsheet) Max range (from spreadsheet) UAV System Design  2002 LM Corporation SAR geometry Earth curvature effects have been ignored • With additional power this SAR should be able to increase WAS and GMTI range to 226 Km • Beyond 226 Km, higher altitude would be required 26-11

  12. Design of UAV Systems 8.7 deg 20.8 deg Max range at 5 degree lookdown = 52 - 87 km 17 –27 deg UAV System Design  2002 LM Corporation SAR geometry (cont’d) This plot also ignores earth curvature effects • With additional power these SARs should be able to increase WAS and GMTI range to 52 - 87 Km • The 102 km WAS requirement means that we have to loiter at a higher altitude, 30 Kft vs. the previous 27.4Kft 26-12

  13. Design of UAV Systems UAV System Design  2002 LM Corporation ID requirement • A different logic applies to the ID mission • We required 100% area coverage because we operate at 10Kft and have ceilings 10 Kft 20% of the time • Now we have to deal with 90% availability • Our only option to increase overall ID mission capability to 89% is to operate at lower altitude • We plot ceiling altitude vs. percent occurrence and estimate that a 7 Kft operating altitude will increase overall target coverage to the required value of 89% 26-13

  14. Design of UAV Systems UAV System Design  2002 LM Corporation Other ID issues • We did not take advantage of EO/IR range to decrease ID mission fly out distance • But this was offset by the fact we ignored time and distance to ID the target and turn back to base • To ensure we have taken all ID requirements into account, we need to model the engagement geometry • We assume the UAV flies directly at the target and upon initial detection (in the spot mode) turns away to intercept a point that will allow a 45 degree lookdown • It then turns into the target flying a constant radius turn and goes back to the initial detection location • Essentially flying a tear drop pattern • During this entire time, the UAV can see the target at a resolution equal to or better than the requirement • Making it a good ID mission sensor figure of merit 26-14

  15. Design of UAV Systems Ground distance for 45 degree look down (distance = altitude) Initial EO/IR detection Constant radius turn Top View 45 degree look down angle Slant range defines initial target detection UAV System Design  2002 LM Corporation ID geometry assessment Turret Type I Spot slant range (SLR) for 0.5m detection = 10Km Turn radius = 1.15 nm G’s required = 1.41 Total Imaging time = 3.2 min Radius extension req’d = 2.2 nm Turret Type II Spot SLR for 0.5m detection = 13.3 Km Turn radius = 1.15 nm G’s required = 1.41 Total Imaging time = 3.94 min Radius extension req’d = 2.1 nm  280 Kts 280 Kts 280 Kts • Conclusions • Even Turret Type I exceeds threshold requirements • Minimum SLR required for ID  3 km • Need to add 2 - 3 nm to required dash distance 7 Kft  Profile View 26-15

  16. Design of UAV Systems UAV System Design  2002 LM Corporation Requirement refinement • Refined WAS SAR range = 102 km at 30 Kft • From our parametric data, for a 55 nm (102 km) range • Power required = 3400W; Weight (uninstalled) = 370 lbm; Volume (uninstalled) = 9.25 cuft • Refined ID EO/IR resolution required = 0.5 m at 3 km • We have no EO/IR range parametrics but from optics, range and resolution should vary primarily with focal length which in turn should vary with turret diameter • We estimate diameter required at  4 inches, well below the smallest sensor in our database • Therefore, we select the smallest EO/IR sensor listed in our database (See Lesson 11): • Turret diameter =9 in; height = 14 in; Weight and volume (uninstalled) = 40 lbm at 572 cuin; Power required = 450W • ID radius for 100% coverage = 141nm + 3 nm = 144nm 26-16

  17. Design of UAV Systems UAV System Design  2002 LM Corporation Refinement (cont’d) • Another issue is “requirement creep” • We have not strictly adhered to our threshold strategy • For example, our UAVs carry SAR and EO/IR sensors • Although operationally advantageous (one payload for both missions), it exceeds our threshold definition • Therefore, we will size for interchangeable payloads • But power and volume available must meet the most stringent requirements for each module • Since the ID mission has the smallest payload but requires the most fuel, we assume that unused payload volume can be used for fuel • We will also retract the EO/IR sensor to reduce drag • Later we can do a cost effectiveness trade study to verify these benefits but for now it is intuitively obvious • However, we will continue to assume that any WAS UAV can function as a communication relay • Another intuitively obvious requirement to test later 26-17

  18. Design of UAV Systems UAV System Design  2002 LM Corporation WAS payload requirement • WAS mission payload • SAR weight (installed) = 370lbm1.3 = 481 lbm • SAR volume (installed) = 9.25(1.25^3) = 18 cuft • SAR power required = 3400W • Basic communication payload (ADT) = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • Relay communication payload = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • Two communication antennae = 2251.3 = 65 lbm at 221.95 = 7.8 cuft • Total WAS mission payload requirement • Weight = 603.2 lbm • Volume = 26.9 cuft • Density = 22.4 pcf • Power required = 4000W At $5000/lbm WAS payload unit cost = $3M 26-18

  19. Design of UAV Systems UAV System Design  2002 LM Corporation ID payload requirement • ID EO/IR mission payload • EO/IR weight (installed) = 40lbm1.3 = 52 lbm • EO/IR volume (installed at h = 14 in) = 1.0 cuft • EO/IR power required = 450W • Basic communication payload (ADT) = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • ADT antennae = 251.3 = 32.5 lbm at 21.95 = 3.9 cuft • ID Auxiliary fuel • Fuel volume available = 26.9cuft – 5.5cuft = 21.4 cuft • Allowable fuel weight = 603.2 – 113.1 = 490lbm • Required fuel volume (at PF = 0.7) = 14 cuft • Total ID mission payload requirement • Weight with zero fuel = 113 lbm • Weight with fuel = 603 lbm • Volume = 26.9 cuft • Power required = 450 W At $5000/lbm ID payload unit cost = $0.6M 26-19

  20. Design of UAV Systems ADT antennae Relay antennae Comm. relay ADT SAR EO/IR ADT antennae Auxiliary fuel ADT UAV System Design  2002 LM Corporation Modular payloads WAS payload ID payload • Consolidated payload requirement • Weight = 603 lbm (max) • Volume = 26.9 cuft • Power required = 4000 W (max) 26-20

  21. Design of UAV Systems UAV System Design  2002 LM Corporation Assessment results • Removing the SAR from the ID mission payload and adding an auxiliary fuel tank significantly increased ID mission capability and drastically reduced cost • Much of the cost saving, however, is due to the reduction in ID payload cost (from $3.5M to $0.6M) • This occurred despite putting a second UAV plus payload on alert to have replacements for both SAR and EO/IR equipped UAVs if needed • This increased the number of UAVs plus payloads required but still traded favorably at the system level • Removing the EO/IR from the WAS payload had some, but not significant, cost and performance benefit • Probably offset by the additional backup requirement • The most cost effective size is now a 18hr WAS endurance vehicle that now can conduct 6 IDs vs. 4 IDs with the original 18 hr baseline 26-21

  22. Design of UAV Systems UAV System Design  2002 LM Corporation Baseline comparisons 26-22

  23. Design of UAV Systems UAV System Design  2002 LM Corporation Threshold requirements • With two exceptions, the new baseline now meets only threshold requirements • 89% WAS target area coverage 90% of the time (the specified flyable days) • Covers 100% ID target area for ceilings at or above 7Kft (for 89% coverage) 90% of the time (the flyable days) • One capability that exceeds threshold is that all WAS UAVs can function as communication relays • This capability trades favorably since at least 2 UAVs need this capability for redundancy and yet a 3rd UAV would still have to be on standby as a replacement • The other capability that exceeds threshold is the ability to provide simultaneous WAS and ID coverage • Without this capability, the system would be of limited operational use (especially at one ID per hour) • No capability to do WAS much (or all) of the time 26-23

  24. Design of UAV Systems 43.4 7.7’ 1.9’ 3.0’ 21.3’ UAV System Design  2002 LM Corporation Threshold baseline W0 =3776 lbm EW = 2101 lbm AR = 20 Sref = 94 sqft Swet = 455sqft Payload = 603 lbm Fuel = 1039 lbm Power = 362 Bhp TBProp Max endurance = 14.5 hrs Max speed = 280 kts Approximately to scale This air vehicle can stay on station for 18 hours at 30 Kft or perform 6 ID missions at 7Kft in 6 hours 7 WAS and 5 ID air vehicles are required 26-24

  25. Design of UAV Systems UAV System Design  2002 LM Corporation Goal requirements • Even though our strategy is to design to threshold requirements to minimize cost, we still need to determine the cost of meeting goal requirements • It might turn out to be cost effective and competitively smart • Goal performance, however, will not be 100% capability • 10% of the days are unflyable, and 90% capability will be the best we can do • Achieving goal performance is simple, we have to cover 100% of the WAS area and ID targets from 1Kft • WAS SAR range required is 71 nm (131 Km) • From our parametric plot, SAR power and uninstalled weight and volume are 4000W, 450 lbm and 11 cuft • Installed weight and volume, therefore, are 585 lbm and 21.5 cuft • And required loiter altitude increases to 37.6Kft 26-25

  26. Design of UAV Systems UAV System Design  2002 LM Corporation Goal WAS payload • WAS mission payload • SAR weight (installed) = 450lbm1.3 = 585 lbm • SAR volume (installed) = 11(1.25^3) = 21.5 cuft • SAR power required = 4000 W • Basic communication payload (ADT) = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • Relay communication payload = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • Two communication antennae = 2251.3 = 65 lbm at 221.95 = 7.8 cuft • Total WAS mission payload requirement • Weight = 707 lbm • Volume = 30.4 cuft • Density = 23.3 pcf • Power required = 4600W At $5000/lbm WAS payload unit cost = $3.5M 26-26

  27. Design of UAV Systems UAV System Design  2002 LM Corporation Goal ID payload • ID EO/IR mission payload • EO/IR weight (installed) = 40lbm1.3 = 52 lbm • EO/IR volume (installed at h = 14 in) = 1.0 cuft • EO/IR power required = 450W • Basic communication payload (ADT) = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • ADT antennae = 251.3 = 32.5 lbm at 21.95 = 3.9 cuft • ID Auxiliary fuel • Fuel volume available = 30.4 cuft – 5.5cuft = 24.9 cuft • Allowable fuel weight = 707 – 113.1 = 594 lbm • Required fuel volume (at PF = 0.7) = 17 cuft • Total ID mission payload requirement • Weight with zero fuel = 113 lbm • Weight with fuel = 707 lbm • Volume = 30.4 cuft • Power required = 450 W No change in ID payload unit cost of $0.6M 26-27

  28. Design of UAV Systems UAV System Design  2002 LM Corporation Goal assessment • Increasing SAR size and WAS loiter altitude increased air vehicle size required • Gross weight = 3482 lbm vs. 2993 lbm for threshold • Empty weight = 1996 lbm vs. 1716 lbm for threshold • Unit air vehicle cost = $798K vs. $686K for threshold • WAS payload size and cost also increased • WAS payload = 707 lbm vs. 603 lbm for threshold • WAS payload cost = $3.5M vs. $3.0M for threshold • ID payload was unchanged at 113 lbm • ID auxiliary fuel increased to 594 lbm vs. 490 lbm • The number of air vehicles required was unchanged • The procurement cost of achieving goal (90%) vs. threshold (80%) increased by $5.9M (17%) • 87% of the increase was the paylaod • Goal capability cost $590K per additional % coverage vs. the threshold average of $425K per % 26-28

  29. Design of UAV Systems UAV System Design  2002 LM Corporation Alternate concepts • The alternatives are resized versions of the baseline • Two (2) air vehicles consisting of 1 WAS UAV and 1 ID UAV • Twenty (20) air vehicles consisting of 16 WAS UAVs and 4 ID UAVs • From experience, we now know what drives the answer • The size and number of payloads (at $5K per pound) • For 89% area coverage, alternative 1 requires one 110 nm (204 km) WAS SAR (uninstalled cost = $6.5M) • Power = 6000 W, Weight = 650 lbm, Volume = 15 cuft • For 89% area coverage, alternative 2 requires sixteen 27.5 nm (51 km) WAS SAR (uninstalled cost = $19.2M) • Power = 1900 W, Weight = 240 lbm, Volume = 6.5 cuft • It is obvious from this simple comparison that the 2nd alternative will not be a cost effective solution • We only need to evaluate alternative 1 (1 WAS, 1 ID) 26-29

  30. Design of UAV Systems UAV System Design  2002 LM Corporation Alternate 1 WAS payload • WAS mission payload • SAR weight (installed) = 650lbm1.3 = 845 lbm • SAR volume (installed) = 15(1.25^3) = 29.3 cuft • SAR power required = 6000 W • Basic communication payload (ADT) = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • Relay communication payload = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • Two communication antennae = 2251.3 = 65 lbm at 221.95 = 7.8 cuft • Total WAS mission payload requirement • Weight = 967 lbm • Volume = 38.2 cuft • Density = 25.3 pcf • Power required = 6600W 26-30

  31. Design of UAV Systems UAV System Design  2002 LM Corporation Alternate 2 ID payload • ID EO/IR mission payload • EO/IR weight (installed) = 40lbm1.3 = 52 lbm • EO/IR volume (installed at h = 14 in) = 1.0 cuft • EO/IR power required = 450W • Basic communication payload (ADT) = 221.3 = 28.6 lbm at 500cuin1.95 = 975 cuin installed at 300W • ADT antennae = 251.3 = 32.5 lbm at 21.95 = 3.9 cuft • ID Auxiliary fuel • Fuel volume available = 38.2 cuft – 5.5cuft = 32.7 cuft • Allowable fuel weight = 967 – 113.1 = 854 lbm • Required fuel volume (at PF = 0.7) = 14.9 cuft • Total ID mission payload requirement • Weight with zero fuel = 113 lbm • Weight with fuel = 967 lbm • Volume = 38.2 cuft • Power required = 450 W No change in ID payload unit cost of $0.6M 26-31

  32. Design of UAV Systems Make sure you check these on your projects UAV System Design  2002 LM Corporation Alternate 2 mission profile • The increased 204 km WAS SAR range requirement requires an increased WAS loiter operating altitude of 58.6 Kft (for a 5 degree look down angle) • Cruise speed must also be increased to compensate • Nominally to 280 kts (5 kts above best loiter speed) • At 58.6 Kft the TBProp is no longer sized by takeoff • Bhp0/W0 must be increased to 0.287 just to reach initial cruise altitude (see Mperf output Hdot4) • Using a standard ceiling altitude definition of 100 fpm • It is also necessary to ensure excess power is available to meet cruise and high speed requirements • See Mperf outputs Hdot4 through Hdot17 • The alternate UAV is larger and more expensive • W0 = 12328 lbm; EW = 7344lbm; Bhp0 = 3489 Hp • 3 WAS, 5 ID air vehicles @ $2.9M ea.; 3 WAS payloads @ $4.84M ea.; Total cost = $40.8M vs. $34M 26-32

  33. Design of UAV Systems UAV System Design  2002 LM Corporation Remaining baseline tasks • Our assessments, therefore, show that the baseline ConOps (1 ID and 4 WAS air vehicles) with the refined air vehicles and modular WAS and ID (with auxiliary fuel) payloads meet our threshold (and goal!) mission requirements at the lowest overall procurement cost • This refined baseline will become our “Preferred Baseline System Concept” • …….. if it meets our risk assessment criteria • The best overall system concept we have found even though conceptual design studies may find better solutions for the individual system elements to include better air vehicle designs, better payloads, etc. • However, the baseline is still not completely defined • We still need to (1) assess risk, (2) determine operations and support requirements, (3) determine manpower requirements and (4) estimate life cycle cost 26-33

  34. Design of UAV Systems Airframe Weight Comparisons - Maximum L/D trends (data from Roskam and Janes) 25 Biz Jet 35 SE Piston Prop 20 30 ME Piston Prop Reg Turbo 25 Jet Trans Model estimate 15 Jet fighters 20 (L/D)max Mil Train Waf/Sref (psf) 10 15 10 5 5 Manned aircraft TR-1 0 Global Hawk (est) 0 0 25 50 75 0 2 4 6 8 GTOW/Sref (psf) UAV System Design  2002 LM Corporation Risk assessment Since we have already compared our initial baseline air vehicle against other aircraft in our parametric database, a quick check of the new baseline should verify that our performance is achievable (i.e. low risk) Wetted AR = b^2/Swet Manned aircraft data : LM Aero data handbook This and the SFC data checks but we still have risk 26-34

  35. Design of UAV Systems Global Hawk Our baseline UAV System Design  2002 LM Corporation Air vehicle risk • Our wing aspect ratio (AR) is well above that of any known air vehicle that has to fly at an equivalent air speed (EAS) of 250 Kts (280 KTAS @ 7Kft ) • High AR wings are susceptible to flutter at high speeds • We have three options for dealing with this risk • Assume someone can solve the problem later, e.g. new • materials or active flutter suppression • Reduce AR to max. demonstrated value (12) • Design a fix (e.g., a quick change wing or removable outer wing panel for the ID mission) 26-35

  36. Design of UAV Systems UAV System Design  2002 LM Corporation Assessment of options • Option 1 is viable if solutions are in work or we are willing to fund the required technology programs • Otherwise we are simply kicking the problem down stream • Option 2 is viable if we can stand the penalty • Spreadsheet analysis shows that at AR=12 we can achieve the same level of mission performance at W0 = 4372 lbm (+596 lbm) and EW = 2369 lbm (+268lbm) • Overall cost increases $1.3M to $35.3M • Option 3 is viable if the design fixes cost < $1.3M • Designing and testing a second wing optimized for the ID mission could easily exceed this cost • A removable outer wing panel might be less complex but (1) attachment provisions will increase wing weight and (2) either more takeoff power or flap performance will be required to offset the reduced wing area • We will use our spreadsheet model to assess Option 3 26-36

  37. Design of UAV Systems UAV System Design  2002 LM Corporation Option 3 assessment • Optimized ID mission wing will not be cost effective • ID mission performance essentially will be unchanged but development program will involve design and test of second wing on one additional flight test vehicle • Vehicle cost alone  $3M • Removable wing panel may also not be cost effective • Assuming 5% wing weight penalty for non-optimum wing but no increase in Clto, Bhp0/Sref = 0.142 (vs. 0.121), W0 = 4081 lbm (+305 lbm), EW = 2325 lbm (+224 lbm) and overall mission cost = $35.1M (+$1.1M) • With 23% increase in Clto (and additional 5% wing weight penalty), W0 = 3929 lbm (+153 lbm), EW = 2216 lbm (+115 lbm) and overall mission cost = $34.6M (+$0.6M) • Assuming development cost proportional to weight of additional wing, development goes up 15% ($13M) • Unless increased O&S cost offsets development, the most cost effective option will be a AR = 12 wing design 26-37

  38. Design of UAV Systems UAV System Design  2002 LM Corporation Risk abatement plan • We identify the issue of high-speed vs. high-AR as high risk and document a requirement for a conceptual design trade study to determine the best option • We select the AR=12 concept as our preferred baseline to ensure “margin” on our air vehicle cost estimates to cover the projected unit cost increase • We will also increase our development cost estimate to cover the cost of additional design, test and evaluation required by removable wing panels • We put an upper limit on development cost of $2M • If it is higher, a better option would simply be to decrease AR to 12 • Otherwise, we see no more high-medium risk issues • Although others could develop as the concept matures 26-38

  39. Design of UAV Systems UAV System Design  2002 LM Corporation RMSS requirements • Reliability, maintainability, safety and support (RMSS) covers a range of operational and technical issues that must be considered from the beginning of a project • See Lesson 12 • The key RMSS issues for our system concept are • The level of redundancy required and • (2) The training, maintenance and support concept • RMSS issues drive operations and support costs, the single largest element of Life Cycle Cost (LCC) • Unfortunately, history is replete with programs that presumed that consideration of these key issues could be put off until later in the program • This is a potentially fatal mistake that always increases downstream cost and risk and sometimes results in program cancellation 26-39

  40. Design of UAV Systems UAV System Design  2002 LM Corporation Redundancy • Two issues drive redundancy requirements • Flight and operational safety • Operations in manned airspace • Safety fundamentally drives operational utility and cost • No user wants to operate a UAV system if there is even a moderate risk of a crash in or around the operating area • Not only because they endanger personnel, crashes are also very expensive • If we plan to operate our UAV in or through civil airspace anytime during its operational life, flight critical systems probably need to be a minimum of “fail safe” • Backup systems allow the UAV to safely return to base after a failure (including engine systems, but not engines) • “Fail operational” is a higher cost option allowing the UAV to continue a mission, albeit with degraded performance • A redundant “See and avoid” sensor and communications capability will probably also be required 26-40

  41. Design of UAV Systems UAV System Design  2002 LM Corporation Training and support • Although other options should be considered later, we will assume that maintenance and support is “organic” • I.e., the using organization is responsible for maintenance • We will use parametric data to estimate the number of maintenance personnel required • Another option is contractor maintenance which probably requires a conceptual design trade study to evaluate • We also assume the user is responsible for proficiency training but that primary training and qualification is done by a separate organization • The number of training systems need to be included in the procurement estimates • Similarly, primary and proficiency training hours need to be included in operations and support costs • These requirements will be documented and included in cost estimates to follow 26-41

  42. Design of UAV Systems UAV System Design  2002 LM Corporation Manpower requirements • Manpower estimates include • Operators (air vehicle, payload, communications and product analysis and dissemination) • Maintainers (responsible for all system elements) • Headquarters staff (management, mission planners, etc.) • Indirect personnel (support personnel, etc) • We already identified a requirement for 7 operators • One WAS + one payload operator (for 4 air vehicles) • One ID air vehicle and payload operator • One payload product analyst and dissemination operator • One launch and recovery operator • One C3I operator (primarily focused on communications) • One back-up operator • For 24 hour, 7 day a week coverage by crews working 40 hours per week at a 125% staffing ratio we require 5.3 crews (which we round up to 6) • Or 42 full time UAV, payload, system, etc. operators 26-42

  43. Design of UAV Systems Predator Global Hawk UAV System Design  2002 LM Corporation Maintenance personnel • Parametric data based on historical manned aircraft experience is used to estimate maintenance manpower required • Note that Global Hawk fits the manned aircraft data • Predator does not which may reflect its Advanced Technology Demonstration (ATD) development history which did not emphasize the importance of maintainability • From this parametric we estimate the number of personnel required • 2.7 maintenance personnel per baseline air vehicle plus payload or 33 maintainers per 12 air vehicle squadron • On average, 6-7 maintainers per 8 hr. shift 26-43

  44. Design of UAV Systems UAV System Design  2002 LM Corporation Other personnel • Headquarters personnel including… • Commanders (minimum of 1 per shift) • Mission planners (minimum of 1 per shift) • Supply and logistics (minimum of 2 per shift) • IT (minimum of 1 per shift) • ..for a total of 51.25 = 7 additional personnel (minimum) • Indirect personnel including…. • Guards, Medical personnel, Clerical staff, Etc. • … are typically estimated at an additional 25% • Therefore, the total squadron manpower estimate is • (42 operators + 33 maintainers + 7 staff)1.25 = 103 heads This may be an optimistic estimate for the number of people required to keep 5 air vehicles on station 24 hours a day, 7 days a week, but unless we can identify the missing tasks, we should stick with this estimate 26-44

  45. Design of UAV Systems UAV System Design  2002 LM Corporation Life cycle cost • Development cost • The cost of developing a system • Considered a “non-recurring” cost • Occurs only once (hopefully) • Procurement cost • The cost to buy a system once it is developed • Includes a lot of “recurring” cost • Costs incurred every time a system is produced • Operations and support cost (Q&S) • The cost to maintain and operate a system after purchase • Includes the cost of maintaining crew proficiency • Excludes the cost of combat operations Development + procurement + O&S  Life cycle cost See Course Review 5.2 (Life Cycle Cost) 26-45

  46. Design of UAV Systems UAV System Design  2002 LM Corporation Life cycle cost Cost methods - review • Airframe • Development - Equations 24.1 - 24.4 • Procurement - Equations 24.5 - 24.10 • Propulsion (procurement) - Eq 24.11 • Ground Station + communications • Development - 70% air vehicle development • Procurement ≈ 1 air vehicle + sensor payload • Payload (procurement) - $5000/lb • Operations and support • Air vehicle & payload operators - estimate number • Maintenance personnel - chart 12-30 • Other personnel - add 25% • Air vehicle operating costs (inc. engine) - chart 24-27 • Ground station + communications - 8% procurement/yr • Payload - 8% procurement/yr 26-46

  47. Design of UAV Systems c 2002 LM Corporation Cost effectiveness Program cost • Development (assuming 3 test aircraft) = $138M • - Airframe (from CERs) + $ 2M = $81M • - Propulsion (off the shelf) • - Control station + comms (@70% airframe) = $57M • - RF and EO/IR payload (off the shelf) • Procurement (assuming 20 aircraft, 12 WAS payloads and 8 ID payloads) = $65.3M • - Airframe (from CERs) = $1.0M each • - Propulsion ($1000/lbm) = $200K each • ID payload ($5K/lb)= $665K each • WAS payload ($5K/lb) = $3M each • 3 Control stations + comms ≈ 3*(1 airframe + 1 payload) = $14M • Average air vehicle + payload cost = $3.3M 26-47

  48. Design of UAV Systems c 2002 LM Corporation Cost effectiveness O&S summary • One UAV squadron consists of 12 air vehicles and 2 ground control stations (1 as back up) • - 10 aircraft assigned to operational missions, 1 in reserve, undergoing maintenance • 6 flight crews are required (rounded up from 5.5) • At 2000 hours per person per year • We assume the squadron performs two (2) 30 day surveillance missions per year • Each 30 day mission requires 5459 flight hours • 160 WAS missions of 25.8 hrs each • 121 ID missions of 14 hrs each • During the other 10 months per year, the squadron trains primarily on simulators, each UAVs flies 1 hr per week for an average of 208 hours per month • Total annual squadron flight hours = 12998 26-48

  49. Design of UAV Systems c 2002 LM Corporation Cost effectiveness O&S and LCC • Annual personnel costs are $5.15M • 103 @ $50K/yr (est.) • Annual air vehicle direct operating costs are $2.46M • - See LCC Review Chart 20 @ EW = 2101lb and Direct operating cost per flight hour (DOCFH) = 0.09$*EW  $189/FH @ 12998 FH/yr • Annual ground station + communications operating costs are $528K • - 2 stations0.08[$3.3M] • Annual average payload operating costs are $2.2M • - 0.0812 [$2.3M]] • Annual O&S costs = $10.34M 20 year Life cycle costs = $410M 26-49

  50. Design of UAV Systems UAV System Design  2002 LM Corporation Final derived requirements • Derived requirements (from our assumptions or studies) • System element • Maintain continuous WAS/GMTI coverage at all times • One target ID assignment per hour • Uniform area distribution of targets • Communications LOS range to airborne relay = 158 nm • LOS range from relay to surveillance UAV = 212 nm • Air vehicle element • Day/night/all weather operations, 90% availability • Turboprop power • Takeoff and land from 3000 ft paved runway • ID/WAS altitudes = 7 – 30Kft • Operational loiter location = 158 nm (min) – 255 nm (max) • Operational loiter endurance = 18 hrs • Loiter pattern – 2 minute turn • Dash speed = 280 kts • Dash distance  860 nm • Dash altitude  7 Kft 26-50

More Related