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Picard578
Riley-AmosAirborne aircraft carrier proposal
Posted by Picard578 on July 1, 2015
Introduction
An airborne carrier will have two versions. First one will be a C-5 cargo aircraft with fighters carried inside its cargo hold. Second one will be a helium Zeppelin. Truth is that airships were used for military purposes during entire World War II, and were extremely successful; Zeppelin will have advantage in loiter time over a C-5, though C-5 will have advantage of cruise speed.
Fixed-wing version
Microfighter design
Basic characteristics
Microfighter will have to have a wingspan of 5,6 meters or less and height of less than 4 m. Length of 12 meters or less will allow three microfighters to be carried per C-5. It will use the same equipment as the FLX, but will have no undercarriage. Instead, a hook will be provided for recovery with C-5. If landing on a strip is necessary, it will perform belly landing.
Unlike FLX, it will be limited to 9 g in order to save weight and cost.
Equipment selection
Due to smaller size necessary, Microfighter will not use EJ200 variant as with the FLX. Rather, M88 variant will be used. While M88 variants had insufficient thrust for the FLX purposes (medium-range lightweight supercruising fighter capable of STOL and dirt strip operations), they will be far better suited for microfighter, where size is the main constraint, rather than fuel capacity or thrust. M88-2 (17.000 lbf AB, 11.250 lbf dry, 1,7/0,8 TSFC) will be used as a base variant with M88-ECO (20.250 lbf AB, 13.500 lbf dry, 1,7/0,8 TSFC) as an upgrade. Both variants are 139” / 353 cm long, with 27,5” / 69,85 cm inlet diameter and 1.978 lbs dry weight.
Other equipment will be the same as for the FLX: GIAT 30, IRIS-T, MICA IR, Skyward-G.
Design calculations
DIMENSIONS:
Length: 11,48 m
Wingspan: 5,02 m clean, 5,48 m armed
Height: 2,98 m
Wing area: 31*474 cm / 2 + 141*474 cm + 582 * 474 cm / 2 = 212.115 cm2 = 21,21 m2
EQUIPMENT WEIGHT:
1 x M88 (1.121 kg installed)
1 x GIAT 30 (120 kg)
1 x Skyward IRST sensor head unit (30 kg)
1 x Skyward IRST processor unit (25 kg)
1 x laser rangefinder transciever (3,4 kg)
1 x laser rangefinder electronics unit (1,3 kg)
2 x RWS 300 front end receiver (5 kg)
6 x RWS 300 antenna (3 kg)
4 x MAW 300 sensor (8,8 kg)
4 x BOP countermeasure dispenser (8 kg)
1 x EWC 300 controller (10 kg)
2 x safety sweitch unit (1,4 kg)
3 x FCS (6 kg)
1 x SysNav (15,6 kg)
1 x radio (3,8 kg)
1 x datalink system (16,8 kg terminal, 6,5 kg RPS, 3*2,2 antennas >> 29,9 kg)
1 x jammer (5,9 kg)
Ejection seat (59 kg)
Electrical (90 kg)
Environmental control, pressurization, oxygen (100 kg)
Hydraulics, actuators (70 kg)
Missile rails (12 kg per rail) – 2 rails
Refueling probe (50 kg)
EPU (79 kg)
Canopy (130 kg)
Pilot w/ G suit, helmet, Mae vest, personal weapon (100 kg)
TOTAL: 2.100,1 kg
AIRFRAME AREA AND WEIGHT:
Vertical tail: (47*159 cm)/2 + 80*170 cm + 100*132 cm / 2 + 100*22 cm / 2 + 188*22 cm = 29.172,5 cm2 = 31,36 ft2 = 51,27 kg
Wings: 167*23 cm + 141*167 cm * 2 + 397*167 cm + 36*14 cm + 54*9 cm = 118.224 cm2 = 127,09 ft2 = 118,09 kg
Canards: 29*34 + 64*34 + 33*42*2 + 37*44 + 78*43 – 61*77 cm = 6.219 cm2 = 6,69 ft2 = 10,94 kg
Body: 366,7 cm circumf * 560 cm + 202 * 35 * 4 + 202 * 70 * 2 + 195 * 70 / 2 * 2 + 161 * 75 / 2 * 2 + 248 * 100 = 284.499 cm2 = 305,83 ft2 = 522 kg
Air ducts: 69 cm circumf * 120 cm + 2 * (215+210) * 35 + 2 * (215+210) * 70 = 115.262 cm2 = 123,90 ft2 = 212 kg
TOTAL: 914,3 kg
FUEL CAPACITY: (0,804 kg/l)
Side tanks:
Avg. crossection: 10.073 cm2 – 3.632 cm2 = 6.441 cm2 > ~6.200 cm2 for both tanks
Top area: 2*282*34 cm + 228*34 cm = 26.928 cm2 for both tanks
Total fuel capacity: 2.127.312 cm3 = 2.127,31 l = 1.710,35 kg
Wing tanks:
Top area: 109*158*2 + 380*158 = 94.484 cm2 for both tanks
Thickness: 10 cm
Total fuel capacity: 944.840 cm3 = 944,84 l = 759,65 kg
Total fuel capacity: 2.470 kg
WEAPONS
1 x GIAT 30 with 126 rounds
5 missile hardpoints (2 IRIS-T, 3 MICA IR standard loadout)
WEIGHTS:
Design empty: 3.014,4 kg
Basic empty (design empty + unusable fuel, undrainable oil, survival equipment): DE + 49,4 kg + 8,97 kg + 72,7 kg = 3.145,47 kg
Operational empty (basic empty + crew, weapons racks, ejectors, gun, etc.): BE + 100 = 3.245,47
Armed empty (operational empty + gun ammo, missiles): OE + 66,78 + 2*87,4 + 3*112 = 3.823,05 kg
Combat (armed empty + 50% fuel): AE + 1.235 kg = 5.058,05 kg
Combat takeoff (armed empty + 100% fuel): AE + 2.470 kg = 6.293,05 kg
NOTES: 2% of the fuel is not usable; oil is 1% of the engine weight; pilot weights 100 kg with equipment; theoretical maximum takeoff weight is calculated with [weight in kg = dry thrust in lb]; practical maximum takeoff weight includes 100% internal fuel and heaviest designed loadout; standard armed emptyassumes gun ammo, 2 IRIS-T and 6 MICA IR; empty weight of EFT is 10% of its fuel capacity.
SPEED
Saab Gripen C has wing span of 45*, dry TWR of 0,625 (5.488 kgf thrust, 8 779 kg combat weight) and cruise speed of Mach 1,15 with 6 AAM (which would give it Mach 1,2 clean). Gripen E is expected to have a dry TWR of 0,631 (5.897 kgf thrust, 9.344 kg combat weight) and cruise speed of Mach 1,25-1,3 with 6 AAM (which would give it Mach 1,3-1,35 clean). In other words, 1% of TWR increase gives 8% speed increase.
I will use FLX numbers where 23% increase in dry TWR increases cruise speed by 17,2%. As Microfighter will have dry TWR of 0,984 at combat weight, a 57,42% increase over Gripen C. Thus, its cruise speed should increase by 42,9% to Mach 1,715 clean or Mach 1,565 with full missile load. Maximum operational speed will be Mach 1,8.
CLIMB RATE AND SERVICE CEILLING
Time to 10.000 meters is 100 seconds for Gripen C, while Gripen NG should better this by 10-15%, again shoving a roughly proportional increase in performance compared to dry TWR. Initial climb rate for Gripen C is 15.240 meters per minute, or 254 meters per second.
Microfighter has a dry TWR of 0,79 at combat takeoff weight, compared to 0,55 for Gripen C, a 43,6% increase. It should climb to 10.000 m in ~70-75 seconds with initial climb rate of 339-362 meters per second. Lower values (higher climb rate) will be assumed due to higher wing sweep. Service ceilling should be 20.340 m.
RANGE
Microfighter will be launched from an airborne platform and will be expected to cruise supersonically for the entire time it is airborne. Optimal supercruise altitude for Microfighter will be assumed as 40.000 ft, whereas C-5 Galaxy has service ceilling of 34.000 ft. It will have to climb 1.830 m, which will be assumed to take ~20 seconds.
Startup: 50 kg
Climb: 21,56 kg
Combat: 432,22 kg
Descent and landing: 20 kg
Landing reserve: 20 kg
Unusable fuel: 34,21 kg
Mach 1,565 cruise to and from the combat area: 1.892,01 kg > 0,4874 h
Combat radius: 405 km
Notes:
Speed of the sound at 30.000 ft is 1.091 kph or 303,1 mps. Microfighter’s supercruise speed in combat configuration is likely achieved at ~40.000 ft, where speed of sound is 1.062 kph or 294,9 mps.
Climb is at full military power.
Combat wing loading should be 250-325 kg/m2.
M88 uses 3.881,59 kg/h at dry thrust and 12.966,56 kg/h at afterburner.
PRICE
Gripen C has a unit flyaway cost of 44 million 2014 USD at 6.800 kg, or 6.471 USD/kg. Gripen Es unit flyaway cost is 43 million USD; at 7.100 kg this gives 6.056 USD/kg. Microfighter has an operational empty wieght of 3.245,47 kg which gives a unit flyaway price of 20.328.000 USD.
Final design
Length: 11,50 m
Wingspan: 5,02 m
Height: 2,98 m
Wing area: 21,21 m2
Canard area:
Empty weight: 3.145,47 kg
Loaded weight: 6.293,05 kg
Combat weight: 5.058,05 kg
Maximum internal fuel: 2.470 kg
Fuel fraction: 0,432
Powerplant: 1xM88-2 afterburning turbofan
dry thrust: 4.976,5 kgf
wet thrust: 7.538,5 kgf
Maximum speed: Mach 1,8
Cruise speed: Mach 1,565 with full missile load, Mach 1,715 clean
Combat radius: 405 km @ Mach 1,565, 444 km @ Mach 1,715
Service ceilling: 20.340 m / 66.688 ft
Climb rate: 339 m/s
Wing loading:
296,7 kg/m2 combat takeoff
238,6 kg/m2 combat
Thrust-to-weight ratio:
1,20 combat takeoff
1,49 combat
G load:
Standard: +9/-3
Override: +12/-3,2
Ultimate: 13,5
AoA limit:
32* operational
100* aerodynamic
Armament:
Guns: 1xGIAT-30 with 126 rounds
5 hardpoints
Sensors:
1 * Skyward IRST (150 km range)
1 * Type 158 laser transciever
6 * RWS-300 RWR
4 * LWS-310 LWR
4 * MAW-300 IR MAWS
Countermeasures:
internal DRFM jammer
disposable jammers / decoys
flares
Unit flyaway cost: 20.328.000 USD
Operating cost per FH: 2.375 USD
Carrier final design
As it can be seen, in this configuration C-5 can carry 2 to 4 Microfighters. Standard loadout will be two Microfighters with additional two left on the ground in reserve. As C-5B has unit flyaway cost of 127,1 million USD, price per air group will be 208,4 million USD.
C-5B data is as follow:
Crew: 4
Payload: 122.470 kg
Length: 75,31 m
Wingspan: 67,89 m
Height: 19,84 m
Wing area: 576 m2
Empty weight: 172.370 kg
Loaded weight: 348.800 kg
Maximum takeoff weight: 381.000 kg
Maximum speed: 932 kph
Cruise speed: 919 kph
Range: 4.440 km with 119.400 kg payload
3 carriers could carry a squadron of Microfighters at price of 625,2 million USD. For comparison, a 4-ship FLX group would cost 157,5 million USD, but would require at least one refuelling (~5.400 kg fuel per aircraft) to achieve 2.200-2.400 km combat radius achievable with C-5 + Microfighter combination. This would mean 1 A-330MRTT tanker per 12 FLXs, at price of 662,6 million USD. Microfighter could also be refuelled by its mother platform.
On the other hand, FLX is capable of road basing and dirt strip operations, meaning that it has more basing options. If necessary however, Microfighter could be used from the ground as well by employing JATO and/or launch ramps.
Ground use
Microfighter could also be launched from the ground by using JATO.
Fuel usage will be as follows:
takeoff: 0 kg (JATO)
climb to 10.000 meters: 75,48 kg
Combat: 432,22 kg
Descent and landing: 35 kg
Landing reserve: 20 kg
Unusable fuel: 34,21 kg
Mach 1,565 cruise to and from the combat area: 1873,09 kg > 0,4826 h
Combat radius: 401 km
Zeppelin version
Zeppelin overview
Hindenburg had following characteristics:
Crew: 40 flight crew, 10-12 stewards and cooks
Capacity: 50–72 passengers
Length: 245 m (803 ft 10 in)
Diameter: 41.18 [58] m (135.1 ft 0 in)
Volume: 200,000 m3 (7,062,000 ft3)
Powerplant: 4 × Daimler-Benz DB 602 diesel engines, 890 kW (1,200 hp) each
Cruising speed: 125 kph (130 kg/h fuel consumption)
Maximum speed: 135 kph (180 kg/h fuel consumption)
Lift: 511.510 lbs (232.017 kg)
Range: 14.000 km
Cruise altitude: 200 meters
In this proposal, helium will be used; this will give a lower weight margin; a conservative estimate of cca 180 tonnes will be used. It will be possible for a carrier to go to 6.000 km distant area of operations in 48 hours, stay cruising there for 16 hours, and return, all without refuelling. Hawaii are 2.390 miles (3.846 km) from California; carrier could go to Hawaii in 31,2 hours, stay there for 49,6 hours and return.
Larger size of a Zeppelin may allow for a full-sized air superiority fighter to be used istead of microfighter; both versions will be designed. Zeppelin will have a service ceilling of 5.000 m.
Microfighter Zeppelin
Each fighter will have assigned four fuel loads and four rearmament batches, in addition to those already filled. This means that total weight carried per fighter will be 18.483,37 kg, allowing a total of 10 Microfighters to be carried. Without rearmament and refuelling requirements, 28 Microfighters could be carried.
Fuel usage will be as follows:
takeoff: 50 kg
climb to 10.000 meters: 50 kg
Combat: 432,22 kg
Descent and landing: 20 kg
Landing reserve: 20 kg
Unusable fuel: 34,21 kg
Mach 1,565 cruise to and from the combat area: 1.863,57 kg > 0,48 h
Combat radius: 399 km
FLX Zeppelin
Each fighter will have assigned three fuel loads and three rearmament batches, in addition to those already filled. This means that total weight carried per fighter will be 26.103,01 kg, allowing 6 fighters to be carried. Without rearmament and refuelling requirements, 16 FLXs could be carried.
Fuel usage will be as follows:
takeoff: 29,69 kg
climb to 10.000 meters: 60 kg
combat: 594 kg
descent and landing: 45 kg
landing reserve: 24,7 kg
unusable fuel: 85,26 kg
mach 1,49 cruise to and from combat area: 3.424 kg > 0,6297 h
combat radius: 498 km
Issues
However, airships are vulnerable to storms, which would make Zeppelins only suitable for calm weather operations.
Conclusion
While fixed-wing carrier will not give any cost or range advantage over FLX + tanker combination, it does have advantage in that fighter pilots will not have been sitting in cockpits for over two hours (138 minutes, to be precise). Better pilot performance due to this is by itself enough of justification of the concept. Further, while tanker can only refuel its assigned aircraft, Microfighter + carrier combination would allow Microfighters to be refuelled and rearmed as needed. Total fuel usage will also be lower, as transport aircraft will be more fuel-efficient. Mothership aircraft itself can be refuelled by a tanker, giving it massive increase in range and endurance. That being said, it will be rather vulnerable unless escorted by AWACS or outfitted with sensors which would allow it enough time after detection for its fighters to intercept the enemy.
Zeppelin carriers would give huge range and endurance advantage, but have issues of weather vulnerability. Microfighter could find usage as truck-launched aircraft; due to high TWR even when loaded, it might be possible to launch them from ramps.
syntaxerror9 said
Go further, give that plane the M88-4E. 😉
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picard578 said
Yeah, could be a good idea.
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Chris said
Out of curiosity, was this inspired by Everest Riccioni’s microfighter ideas?
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picard578 said
Yes.
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Andrei said
With a wing this small it might be a better idea to go with a Forward Swept Wing. The main advantage of a Forward Swept Wing is that it offers greater Lift then a normal wing of the same wingspan and wing Sweep. It also gives a lot of the advantages of a Delta Wing/Closed Coupled Canard configuration, mainly in regards to Post-Stall Maneuvering: due to the flow of air over a Forward Swept Wing, when the wing stalls the first part to stall is the root not the tips as in a normal wing. Thus the roll of the aircraft is still controllable as the ailerons are still functioning and spinning can be prevented. Also the best configuration of a Forward Swept Wing is with a Close Coupled Canard. The main disadvantage is that the wing will have to be made from composites to prevent breaking, but even this can be turned into an advantage as with composites the wing can be tailored to bend in the most desired way.
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picard578 said
True, but I didn’t want to experiment too much and delta wing does give better fuel volume.
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Andrei said
Nobody stops you from doing a sort of reverse delta-wing. Both the Suhoi Berkut and the X-29 the only two experimental FSW fighters have had wings that were blended with the tail plane and resembled somewhat a reversed delta wing:
https://en.wikipedia.org/wiki/Grumman_X-29
https://en.wikipedia.org/wiki/Sukhoi_Su-47
In the case of the Microfighter a reversed Delta-Wing comes naturally. With a Forward swept wing with Close Coupled Canards one of the requirements is for the Root of the wing to have a normal sweep (
Design for Air Combat Hardcover by Ray Whitford – chapter on wing selection). Coupled with the big sweep needed for the Micro Fighter the result will resemble a reversed Delta Wing. 🙂
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picard578 said
It won’t, because forward as well as rear edge of the wing have to be swept forward. Maybe reversed cranked arrow, but that is the closest it gets. I’m also concerned about maintenance requirements as reversed sweep wings have to tolerate huge and rather unnatural stresses.
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Chris said
I’d be worried about the aeroelastic twisting such wings get.
Historically, another issue has been that forward swept wings can get into an irrecoverable stall, which can be very problematic.
I’d say the main reason why Delta is best is for supersonic travel, voricies at high angles of attack, lower wing loading, and internal fuel.
I think that a FSW is possible, but it would need very extensive testing. Like the Su-47, it may be something that is a one-off for now and only after extensive experimentation will it become mainstream.
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Andrei said
“Maybe reversed cranked arrow, but that is the closest it gets.”
That’s what I meant I expressed myself wrong. I’m used to calling cranked-arrow, double delta which is a subset of delta 😀
“I’d say the main reason why Delta is best is for supersonic travel, voricies at high angles of attack, lower wing loading, and internal fuel. ”
Those are also the same advantages of Forward Swept wing if one goes for a reversed cranked-arrow. To which we add increased control in post-stall maneuvers if the twisting problem is resolved. See bellow.
“I’d be worried about the aeroelastic twisting such wings get.
Historically, another issue has been that forward swept wings can get into an irrecoverable stall, which can be very problematic. ”
The aeroelastic twisting is a problem: the tip of the wing twists in opposite direction to a normal wing which leads into the irrecoverable stall problem … but usually one dose not get into the stall because the wing breaks long before it.
The solution to this problem is aeroelastic tailoring of the wing: usually using composites with fibrous components such as carbon fiber, a structure is created in which the fibers run in three directions, two perpendicular to each other corresponding to the longitudinal and lateral axes of the aircraft, and the third bisecting this directions, each direction of fibers in a different layer. This structure causes the tip to actually bend in the opposite direction lowering the angle of attack of the tip of the wings. This eliminates the irrecoverable stall problem, because stalling now occurs at it would if aeroealstic effect would not be taken into account: first at the wing root while the tips and the ailerons don’t go into a stall and maintain their controls authority. Only the tips of the wings( i.e the part of the wing in which both sides are forward swept) would have to be made in this way, the root of the wing which would have a diamond shape, similar somewhat to the wing of an F-22 would not have the same problem. Making the tips of the wing from composites might actually decrees maintenance work, if their are made detachable, they could be made expendables and if produced and/or refurbished in big enough numbers economies of scale would work to lower their price.
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Chris said
I think it’s definitely a viable concept. I would love to see more R&D in this area.
Eventually, I’d love to see a fighter aircraft as well, like you. In theory, this could lead to a very maneuverable aircraft, especially at high angles of attack and likely a very high L/D ratio. I would imagine that a forward swept flying wing, if such a thing were possible, would be the most “efficient’ design possible.
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Chris said
To be honest, in many ways, the whole field of aviation has stagnated I would think.
Areas we are seeing some improvements:
– We have seen progressively higher inlet temperatures for jet engines and engines that get more efficient
– Somewhat related, we do see better materials sciences (carbon fibre being an example)
– Since the 1950s, progress seems to have slowed though
– The supercritical wing I suppose could be argued as a major innovation
Elsewhere though, I think there have been stalls:
– I’d like to see if we could somehow come up with a lightweight material to reduce the exposure to radiation (important in part because with pilots training 50+ hours per week as Picard would like, they’d get quite a bit of radiation)
– Compression wave riding might be a way to reduce the wave drag from supersonic (abandoned since the cancellation of the XB-70 Valkyrie)
– It has been suggested that one way to reduce the supersonic wave drag might be applying electrical charges on the airfoils – I’d love to see if this could be done or if this is a dead end
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pehjihhou said
you must be mad to imagine something as large as this without the benefit of the cover of the horizon, I might as well as provide my air-force with mid air refuel as poo-pack for increase loitering time
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picard578 said
mad, maybe… but idea existed before, with IR AWACS around, any fighters will be detected long before they get within effective missile range (which is no more than 100-150 km even for Russian anti-AWACS missiles).
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picard578 said
That being said, I’m more than a little sceptical about the idea myself.
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Andrei said
“you must be mad to imagine something as large as this without the benefit of the cover of the horizon, ”
What cover of Horizon. That has been long gone ever since the aircraft was invented. Do you think an aircraft Carrier can use horizon to hide from an AWACS or Maritime Patrol Aircraft. An airship might not be able to use horizon for cover, but guess what, neither will any ship or aircraft. If the airship has been detected by something you can be damn sure that the airship has also detected that something. With cover taken out of the question the problem becomes one of energy, who has the energy advantage wins. And unfortunately for any ship trying to hide, unsuccessfully, behind the horizon, the airship will always have a huge potential energy advantage just by being higher. The missiles and/or projectiles launched by the ship will have a much smaller range that the equivalent missiles/projectiles launched by the airship. Same for aircraft. While aircraft launched from a surface based carrier will spend almost half their fuel to get to the altitude of the airship, any aircraft launched by the airship will already be at altitude and will have much more fuel available . With similar aircraft and similar trained pilots the ones with more fuel win.
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Chris said
Actually now that I think about it, the viability of large surface combat ships might be in danger.
Even larger ships like the Kirov class may have difficulties defending against an airship, if enough are built. It would be another threat, much like submarines are today.
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picard578 said
Actually, classical airships have lower altitude limits when compared to fixed-wing aircraft. A rigid-body hybrid might be doable.
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Andrei said
Well I was thinking of rigid body hybrids like the ones from Aeroscraft ( http://aeroscraft.com/ ) that I talked about a while back, or Lockheed Martin P-791 ( http://www.flightglobal.com/news/articles/skunk-works-p-791-airship-revived-as-civil-cargo-lifter-354698/ ). I believe a classical Zeppelin is not worth doing these days, for military applications, it might be slightly cheaper, but I doubt it, then a hybrid but it dose not have the versatility of one.
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Chris said
I suspect that both the airship and the “naval” ships could have specially armed weapons to kill each other – SAM missiles for the boats and anti-shipping missiles for the airships.
Strictly from a fuel and range perspective, the airship does have the advantage in shooting from “sky to the surface of the ocean”.
The other issue is that if you do send a refuelling tanker in, the airship IRST is likely to detect it (and has the option) to scramble it’s fighters too.
An IR-based variant of an anti-AWACS missile may be another option vs refuelling tankers – they are not very agile (perhaps even less than a commercial jet as they are loaded with fuel).
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Chris said
Off topic, but the Russians too are cutting back on the PAK FA
http://m.in.rbth.com/economics/2015/03/25/russian_air_force_to_buy_fewer_pak_fa_fighter_aircraft_42179.html
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picard578 said
Not surprising.
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Chris said
The irony here is that such aircraft may simply prove too unaffordable.
I wonder if someone in Russia is going to do a serious analysis considering the cost difference between an “upgraded 4th generation” Su-27 vs a PAK-FA?
Then consider whether an equal cost of those modern Su-27 could win vs a PAK-FA? I ask this because although the Su-27 is too large to be a “good” fighter (although for it’s size, its quite agile), they are far more likely to realize the weaknesses than the American MICC.
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picard578 said
They did realize weankesses. PAK FA is actually designed to play on F-22s and F-35s weaknesses, which is huge IR signature and need to use radar for engagement. That being said, it has some less than enviable design choices that are a consequence of its Flanker legacy – widely separated podded engines, while good for ground attack survivability, significantly reduce agility.
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Andrei said
“widely separated podded engines, while good for ground attack survivability, significantly reduce agility.”
I think that this configuration was chosen by the Russians more with peace time operation in mind. The separated podded engines ensure that if one engine is damaged the other is not affected like it happens in two-engined aircraft with the engines close together (you’ve given some examples of Eurofighters and Rafales where one engine stopping caused the other to stop as well.). Even if this configuration dose not help in combat it helps when doing long range patrols over the frozen north and loosing an engine, if the other one still functions one can return to base which in the case of Norther Russia or Siberia might be 1000 km away.
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Chris said
True that – I suppose, but even then the PAK FA is unaffordable.
It will be a more agile fighter in close range than the F-22 (better airframe characteristics for sure) and arguably a “better aircraft” at long range (fuel fraction is unknown but a poster from Defense Forum India thinks it’s 0.36 vs 0.29 on the F-22). (See http://defenceforumindia.com/forum/threads/sukhoi-pak-fa-and-fgfa-fifth-generation-fighter-aircraft.8276/page-137, go to post 2731). On the other hand, even that has gone down from the Su-35BM, which apparently was 0.42?
There is one thing I am interested in – do flat nozzles reduce IR signature? Medium has an interesting article:
View story at Medium.com
Flat nozzles probably lose thrust (Victor Mikhailovich Chepkin of Lyulka-Saturn claims 14-17%), weighs more, and I would hesitate to guess the corners probably are not as strong (circle is always going to be stronger).
I suppose even if it did work, it wouldn’t be a huge advantage and I would hesitate to guess that it ‘s a pretty big maintenance issue.
I don’t think it’s worth it – I think round nozzles are still a better choice.
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picard578 said
Flat nozzles do reduce IR signature, but it doesn’t really make much difference.
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Chris said
Yeah given the cost and other requirements, I would argue flat nozzles are not a good deal.
On the note of the PAK-FA, 0.36, although better than the Western crop of fighters (save maybe the F-35 and that probably has a very bad lift-drag ratio), is still a downgrade from the original Su-27 and as the Defense Forum india post noted, the Su-35BM’s 0.42 (imagine what a hypothetical aircraft like the Su-35BM as a bomber interceptor could be without the radar and perhaps as a true delta – that’d be a very long ranged interceptor). I suppose the larger fuselage must have soaked it up. It may be that radar stealth cannot build a high fuel fraction aircraft.
The Medium article is mostly otherwise I think correct. The F-35 is hopeless in the air to air mission and is only going to ever be bombing.
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picard578 said
No, stealth always means lower fuel fraction for a given basic design outline.
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Chris said
Yeah I’m not surprised at the fact that stealth means low fuel fraction.
Actually, the problem is probably worse then that. Radar stealth means having to have a very large fuselage that covers the weapons which means:
– Fuel fraction is lowered because fuselage is larger
– Lift-drag ratio in a “clean” configuration is worse than a non-stealth aircraft due to large fuselage
– Higher wing loading (also due to the increased weight)
– Dogfighting performance is worse
That doesn’t even begin to address other issues such as cost, stealth coating, maintenance, etc.
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picard578 said
Precisely.
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Andrei said
Slightly off topic:
.I found a three part article on the Rafale that is very interesting. Probably you guys, already know this series of articles, but if you don’t here are the links:
http://ottawacitizen.com/news/national/defence-watch/the-rafale-as-canadas-next-fighter-part-1
http://ottawacitizen.com/news/national/defence-watch/the-rafale-as-canadas-next-fighter-part-2
http://ottawacitizen.com/news/national/defence-watch/the-rafale-as-canadas-next-fighter-part-3
The series is very well documented and up to date with the latest avionics iterations on the Rafale, and draws some interesting conclusions such as this at the end of part 2:
“This advanced, integrated EW capability is another area where the Americans are actually playing catch-up. The Rafale is the only aircraft delivering this advanced combat capability on the market today. The Boeing EA-18G Growler, the electronic warfare variant of the F-18 Super Hornet, will only be getting this capability in a next generation external jamming pod from Raytheon on 2020. In order to have the air-to-air, air-to-ground AND EW capabilities at once, you need to fly both the SuperHornet and Growlers – two jets compared to one Rafale.”
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Chris said
Yep.
A bit off topic, but Ottawa is actually where I live. The Ottawa Citizen is a well known, right wing paper, probably the most read.
I find myself disagreeing with their editorial position a lot, but on this one I agree with. The US is behind in several areas in terms of electronics.
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stormshadow said
Why not use a seaplane with a 15 diameter fuselage so it could carry every NATO aircraft except the A-10 and could carry of course the FLX/ALX/OLX. Also because such a aircraft could land on 70% of the earth area, it would be much less vulnerable than a ground base aircraft who need vulnerable runway.
Such a seaplane could be refuel by tanker-boat or even could be nuclear engine.
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picard578 said
I wanted to use an existing aircraft for that, and I’m not sure there is a seaplane large enough.
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stormshadow said
Maybe you can design a seaplane airborne aircraft carrier. The only constraint would be that such a seaplane would need a 15m diameter cabin so it could carry and deploy every NATO fighter (except the A-10) as well as the FLX/ALX/OLX. Such an aircraft could be nuclear powered so it would have an unlimited range/endurance and could produce fuel from seawater.
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picard578 said
It would probably cost more than an aircraft carrier though.
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stormshadow said
Maybe but an aircraft carrier is very vulnerable to submarine and ASM and even TBM (Theatre Ballistic Missile). And US Navy admiral say US Aircraft carrier would last no more than 2 days against the soviet navy during the cold war.
A airborne aircraft carrier would be much less vulnerable because of the speed and altitude and could go closer to targets especially those deep inland and so increase the number of sortie and time on station against any target compare to a seaborne aircraft carrier
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InACloud said
Instead of microfighters, I would think this sort of airborne aircraft carrier design has already been proposed, but with drones instead. At least the drone operators could be on the actual airship instead of multiple timezones away.
Speaking of small jet fighters, have you heard of the “fighter in a box” concept?
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picard578 said
Drones and UAVs are ways off from being capable of engaging in air-to-air combat. Drones are too stupid to more than annoy human pilots, and UAVs have major lag issues, plus the prospect of the entire fleet crashing due to a bit of jamming.
Yes, I have heard of FINAB. Quite good concept, and I expect my own Microfighter would be usable for it.
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InACloud said
I would think that an airship carrying drones it can retrieve means that the communications lag isn’t as much of a factor anymore (the airship isn’t continents away). At least with COIN it could be useful. Of course, if the airship itself is armed it can hold ground and offer air support within visual range without expending fuel (assuming the weather is co-operative if it isn’t using an anchor) but that’s another story.
If you’ve heard of FINAB, will you be covering other concepts from the old Combat Reform website? I think that’s the only place I’ve heard of FINAB. Warplanes with folding wings are WWII technology, so perhaps one could start there, or bring back Variable-Sweep wings so planes can fit into tight confines as well as take advantage of the maneuverability and take-off distance gains.
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picard578 said
Airship would be vulnerable though, and uplinks can be jammed (which is one of my primary issues with drones). And drones in COIN are only good for surveillance, armed drones have so far proven to be only helpful for the terrorists.
“If you’ve heard of FINAB, will you be covering other concepts from the old Combat Reform website? I think that’s the only place I’ve heard of FINAB.”
Yes, I know of it and I may cover some of the concepts in the future. Next year though, as I’m currently on a hiatus and my posting schedule is taken up until after the Christmas anyway.
“Warplanes with folding wings are WWII technology, so perhaps one could start there, or bring back Variable-Sweep wings so planes can fit into tight confines as well as take advantage of the maneuverability and take-off distance gains.”
Variable sweep wings are a failure for air superiority, wing loading is high due to small wing area, at high speeds they offer no advantages over conventional swept wings, at low speeds lift gain due to low sweep is insufficient to offset increase in wing loading, while at the same time large wing span and comparably small control surfaces result in sluggish roll response. Canard-delta is a far better choice, especially for maneuverability and STOL purposes. Variable sweep also requires heavy and complex machinery in wing root, increasing weight and maintenance requirements.
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rapemeanaly said
this concept has been tried already and it doesn’t work. Namley the part about reattaching with the hook.
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picard578 said
That, and the concept itself may not be very viable even if the hook problem is solved.
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chairmanchaffers said
http://aviationweek.com/defense/airship-carriers-could-extend-smaller-uas-capabilities
Seems the idea is gaining attention..
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picard578 said
Yeah… and when I remember how some laughed at the idea.
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duct cleaning equipment said
duct cleaning equipment
Airborne aircraft carrier proposal « Defense Issues
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Riley-Amos said
Worth suggesting is that for low-intensity conflicts, the mother aircraft would carry CAS aircraft, it could loiter a little ways away from the conflict for far longer than a standalone CAS fighter could. It would carry something along the lines of Burton’s Blitzfighter or your Light CAS proposal – these would need only a tiny amount of fuel and could therefore be either very small, or carry a lot of ammunition.
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picard578 said
Agreed, that is another possibility. Maybe OLX could be carried, it has very long endurance itself but not that long range due to slow speed.
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Alex said
Some imaginary airships for ideas and inspiration:
https://www.artstation.com/artwork/brddG
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