Cost effectiveness and feasibility considerations on the design of mini-UAVs for balloon takedown. Part 3: reliability and availability

Figures & data

Table 1. UAVI basic data with F104C (*) as a full-scale reference airplane (Figure 1).

Parameter	F104C (F-104 A, B, C & D Flight Manual, 1968)	F104 1:6 single cannon
Length (m)	16.66	3.3
Wingspan (m)	6.63	1.1
Wing area WA (m^2)	18.22	0.5
Empty weight (kg)	5788	24
MTOW (kg)	12634	52
Half Internal Fuel Mass (kg)	1138	8
Reference mass (kg)	6926	32
Wing loading at reference mass (kg m^-2)	380.1	64
Maximum static thrust dry (N)	44,500	1251
Maximum static thrust with afterburner (N)	70,300	–
Trust loading-reference mass dry (N kg^−1)	6.42	39
Trust loading-reference mass with afterburner (N kg^−1)	10.1	–
Maximum speed (M)	2.2 M at 15,240 m (2.2 M at 50,000 ft)	1.6 M at 28,956 m (1.6 M at 95,000 ft)(***)
Ceiling	17,678.4 m (58,000 ft)	28,956 m (95,000 ft)

^(***) Limited by the high-altitude fixed-geometry air intake.

Table 2. UAVI sub-assemblies list.

Sub-assembly	Position	Reference number (#)
Airframe	Entire airplane	1
Jet engine	Rear	2
Communication	Centre-nose	3
Autonomous control	Centre	4
Manual control	Centre	5
Rescue system (trap)	Centre	6
Emergency parachute	Rear	7
Fuel system	Centre	8
Battery pack	Nose	9
Cannon pack	Rear	10

Table 3. Airframe (1) reliability.

Sub-assembly	Life reliability (25 h)	Mission reliability (0.5 h)
Structure	1	1
Rudder servo	0.99999967478861961906	0.99999999349577139979
Rudder	0.99999994999500063647	0.99999999899989999713
Elevator servo	0.99999967478861961906	0.99999999349577139979
Elevator	0.99999994999500063647	0.99999999899989999713
Left aileron servo	0.99999967478861961906	0.99999999349577139979
Left aileron	0.99999994999500063647	0.99999999899989999713
Right aileron servo	0.99999967478861961906	0.99999999349577139979
Right aileron	0.99999994999500063647	0.99999999899989999713
Variable nozzle servo	0.99999967478861961906	0.99999999349577139979
Variable nozzle	0.99999994999500063647	0.99999999899989999713
Airframe (1) total	0.9999981239195904613	0.9999999624783575803

Table 4. Jet engine (2) reliability.

Sub-assembly	Life reliability (25 h)	Mission reliability (0.5 h)
FADEC (3-time redundancy)	0.99999999655165490476	0.99999999999997235187
Air to fuel heat exchanger	0.99999999655165490476	0.99999999655165490476
Fuel pump	0.99989583875849218034	0.99999791666883680404
Pressure regulator for air bleed	0.99989583875849218034	0.99999791666883680404
Jet assembly with alternator	0.99975003124739599608	0.99999500001249996822
Jet engine (2) total	0.99954176479181383610	0.99999082992700594945

Table 5. Communication package reliability.

Sub-assembly	Life reliability (25 h)	Mission reliability (0.5 h)
Comm. package (3) total	0.9999794392580720352	0.99999999982867504572

Table 6. Autonomous control (4) reliability.

Sub-assembly	Life reliability (25 h)	Mission reliability (0.5 h)
Autonomous control (4) total	0.99920031991468373060303	0.99998400012799926179

Table 7. Sub-assemblies reliability total.

Sub-assembly (#)	Life reliability (25 h)	Mission reliability (0.5 h)
Manual control (5)	0.99999999749998750304	0.99999999749998750304
Fuel system (8)	0.99998717675862158755	0.99999974353356091411
2-Times redundant battery pack (9)	0.99999999998999999980	0.99999999999980004878

Table 8. Cannon system (10) reliability.

Sub-assembly	Life reliability (25 h)	Mission reliability (0.5 h)
Cannon, shell, firing system	0.98347145382161748947	0.9996667222160499077
Laser range finder	0.99924271113048742165	0.9999848485996321034
Total	0.98272668183615502487	0.9996515758653071495

Table 9. Rescue system (6) reliability.

Sub-assembly	Life reliability (25 h)	Mission reliability (0.5 h)
Airbrake servo	0.99999967478861961906	0.99999999349577139979
Airbrake	0.99999994999500063647	0.99999999899989999713
Parachute deployment system	0.99999994999500063647	0.99999999899989999713
Hook servo	0.99999967478861961906	0.99999999349577139979
Hook	0.99999994999500063647	0.99999999899989999713
‘Pilot error’	0.99999238522712130534	0.99999984770397420947
Rescue system (6) total	0.9999915847956684401	0.9999998316952195228

Table 10. Comparison between the current missiles and the system offered in this study.

	Success rate (%)	Capabilities
Russian air-launched cruise missile	40–80	The missile can cover a distance of 4500 km. The Russian Air Force employs the Kh-102 missile in conjunction with the Kh-101. The Kh-BD is a forthcoming cruise missile anticipated to have a range exceeding 3000 km.
North Corean ballistic missile	85	This missile has a range of 4500 km, making the US island of Guam accessible. Additionally, North Korea has tested the Hwasong-14 ballistic missile with a reported range of 8000 km, but studies propose it might reach up to 10,000 km, potentially reaching New York.
US missiles in ‘endgame’ mission	43
Iron dome	>90	Over 5000 interceptions, effective against rockets, mortars, artillery shells, aircraft, helicopters, and UAVs.
AIM-9X Block II Sidewinder	99.7	Significant advancements from the older AIM-9B version, including helmet-mounted display and improved manoeuvrability.
Stinger missile	>90	Supersonic speed, agility, accurate guidance and control system, used on Apache helicopters for air-to-air engagements.
Mini-UAV interceptor	98	Each mission lasts 30 min max, therefore the JUAVI life is limited by the cannon to 250 h.

Figure 1. F104 1:6 single cannon (schematic). The cannon is the red cylinder at the root of the tail.

F-104 A, B, C & D Flight Manual (1968).

 Google Scholar

Data availability statement

Not applicable.

Figure 1. F104 1:6 single cannon (schematic). The cannon is the red cylinder at the root of the tail.