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Author Topic: Grumman Pre-ATF & ATF Studies  (Read 67309 times)

Offline asiscan

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Re: Grumman Pre-ATF & ATF Studies
« Reply #120 on: January 27, 2018, 05:22:47 pm »
Some useful info gleaned from ADA081055 (AFFDL TR-79-3104) "Investigation of MSLPC and Crew Escape System Integration." Sept 1979.The baseline aircraft design studied was a derivative of Grumman/AFFDL Config Development of Advanced Fighters (CDAF) program. According to Grumman docs the CDAF was running parallel from mid 1977 with the earlier ATS and STAC programs. The drawing of the a/c on page 155 of the above doc (page 174 of the PDF) gives a designation of ASL-495F-007A for the baseline fighter design and ASL-495F-007LPC for the modified Low-Profile Cockpit configuration. This was based on the CDAF design of the ASL-495F-007. The larger, baseline Mach 2.0 Penetrator (page 156 of the doc/page 175 of the PDF) variant appears to be designated the ASL-495F-006. In APPENDIX E - FIGHTER APPLICATION DATA (page 201 of doc/page 220 of PDF) some additional data is burried in the CISE computer program input listing. Design mission profile is included in the listings.

Here's some additional a/c details from the listing that are not in the drawing:

Grumman ASL-495F-007A - Mach 1.6 Fighter/Attack aircraft (as of Feb 1979)
[indicates Grumman ASL-495F-007 - CDAF Mach 1.6 Fighter/Attack aircraft - data as of Nov 1978, all else is same as -007A]

Length: 56 ft (assuming fuselage, not overall)
Wing Area: 368 [365]
Wing Aspect ratio: 3.0
Wing T/C (root): 0.045
Wing leading edge sweep: 57 deg
Wing taper: 0.15
Vertical tail Area: 71 [70]
Vertical tail Aspect ratio: 1.03
Vertical tail T/C average: 0.036
Vertical tail 1/4 chord sweep: 52.8 deg
Vertical tail taper: 0.168
Canard Area: 57 [56]
Canard Aspect ratio: 2.68
Canard T/C average: 0.036
Canard 1/4 chord sweep: 46.7 deg
Canard taper: 0.160

Max Mach speed: 1.90
SL max Mach speed: 1.20
Ultimate Load Factor: 9.8g
Takeoff distance (ground run): 925 ft
Takeoff wing loading: 65.6 lb/ft2 [65.7 lb/ft2]
Takeoff T/W: 1.027 [1.028]
Landing stall speed: 117 knot [118 knot]
Landing distance (ground run): 1065 ft
Total thrust SLS (max A/B): 24791 lb [24625 lb]

Empty weight: 15589 lb [15492 lb]
Stores: 1000 lb
Takeoff weight: 24128 lb [23944 lb]
Combat weight: 22805 lb [22630 lb]

Propulsion: 2 x CDAF study-YJ18 (?) turbofan with A/B

I didnt include the Mach 2.0 Penetrator data - I didnt want to burden forum thread members with info they might already have.

Cheers.

« Last Edit: January 27, 2018, 06:51:28 pm by asiscan »

Offline PaulMM (Overscan)

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« Last Edit: January 28, 2018, 12:52:39 am by PaulMM (Overscan) »
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Offline PaulMM (Overscan)

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Re: Grumman Pre-ATF & ATF Studies
« Reply #122 on: January 27, 2018, 11:49:45 pm »
NASA Contractor Report 3763 A Wing Concept for Supersonic Maneuvering W H Mason
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Offline hesham

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Re: Grumman Pre-ATF & ATF Studies
« Reply #123 on: December 04, 2018, 05:25:59 am »

Offline PaulMM (Overscan)

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Re: Grumman Pre-ATF & ATF Studies
« Reply #124 on: Today at 12:20:20 am »
This "reduced RCS" design was targeting an "order of magnitude" reduction in RCS. Seems to be the low altitude counterpoint to the GASP design.

Quote
The fourth category examines weapon systems designed with RCS signatures significantly lower than traditionally-treated aircraft of conventional architecture. While the previous two categories stressed the capability to deliver a wide variety of current/near-term munitions, the low RCS concepts have relaxed weapons flexibility to achieve maximum observables reduction. Individual designs were developed for low and high penetration alternatives in response to differences in vehicle shaping and inlet/airframe integration.

[...]

At high altitude, supersonic capability (both cruise and maneuver) is still required by both "dedicated" and "treated" concepts. Although DECM power requirements are less with an order-of-magnitude reduction in RCS, a DECM suite is still necessary for survivability against surface-to-air threats. Therefore, the benefits associated with RCS control reach a point of diminishing returns in the high altitude case: the RCS-treated concept, with architectural freedom to more efficiently address other mission/survivability considerations, is a slightly more effective solution.

At low altitude, the effectiveness levels for treated and dedicated RCS concepts are again comparable, but with the above effectiveness trend reversed.This occurs because the dedicated RCS concept can achieve competitive survivability levels without a supersonic dash, and it therefore is designed purely as a subsonic (low cost) vehicle. To complement this vehicle's low RCS architecture, the avionic systems also have been fashioned to minimize their RCS contribution (described in the next section).
Furthermore, to achieve the desired RCS level, weapon flexibility was de-emphasized in favor of an architecture geared to WASP only, with internal carriage to minimize the signature impact of the weapons. Thus, the baseline RCS-treated concept is larger not only to provide supersonic dash capability but also to address carriage of the current/near-term weapon inventory. In the net, for low altitude penetrators, a tradeoff exists between effectively killing targets with a low RCS WASP-dedicated concept and the weapon flexibility inherent in a more traditional low altitude concept.

[...]

An RCS-dedicated concept is illustrated in Figure 18. It is a high wing design, with a flush engine air inlet limiting the configuration to subsonic speeds (consistent with the observations in the previous section). The vehicle is also designed specifically for carriage of WASP weapons in a "flat pack" installation atop the fuselage, a rather "natural" integration, given the fuselage shaping for RCS control. This weapons integration approach helps make the design a small and cost-effective (but operationally limited) weapon system concept.

The avionic systems integration complements the low RCS theme for this design. The SAR, placed behind a fenestrated radome, includes low probability of intercept (LPI) features such as a low peak power transmitter with the radiation spread temporally, spectrally, and spatially. The antennas for the DECM and communication/navigation/ identification systems are generally flush mounted and placed in treated cavities or, where appropriate, use designs such as spirals which inherently offer low RCS.


Future Strike Fighter Options... Concepts and Technologies
Paul C. Bavitz
Advanced Air Force Programs
Grumman Aerospace Corp.
1981

Artwork from Bill Sweetman Aircraft 2000 - The Future of Aerospace Technology
« Last Edit: Today at 12:45:04 am by PaulMM (Overscan) »
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Offline hesham

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Re: Grumman Pre-ATF & ATF Studies
« Reply #125 on: Today at 03:59:41 am »
Nice find my dear Paul.

Offline sferrin

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Re: Grumman Pre-ATF & ATF Studies
« Reply #126 on: Today at 05:21:29 am »
Interesting how people in the public seemed to be convinced rounded shapes were the way to achieve stealth and then when we see the real things they're all sharp edges, pretty much the opposite.
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