Nov 222011

In our latest article in a series on the Bell D188A/Model 2000 supersonic VTOL fighter of the late 1950s, we present more primary documents concerning this aircraft in a chronological sequence, specifically Bell progress reports and correspondence in the September—December 1958 period. In the paragraphs below, we reproduce the abstracts of each report, which can be read in depth by clicking through the image gallery above.

In the September Progress Report, dated October 15, 1958, Bell noted that it had submitted comments to BuAer on its Addendum No. 71 to Specification MIL-D-8706(Aer)-1, “Contract Design Data Requirements for Model VF VTOL Airplane.”

Correlation of predicted data with wind tunnel data indicated that the Bell Aircraft Corporation method of predicting drag was essentially accurate.

The 1/10 scale jet impingement model had been returned to the test stand equipped with air induction systems for the forward fuselage and nacelle inlet locations.

During this reporting period, it was decided to utilize a Type III (400°F) hydraulic system, owing to the high temperature environment in the fuselage aft engine region.

A total of 14 drawings were completed during September, despite the fact that the fuselage lines were changed to reduce its sectional areas and the tail surfaces underwent revisions to improve their flutter characteristics.

Installation requirements for the Sidewinder were reviewed with personnel at NOTS. It was learned that Sidewinder launching imposed less of a stability and control requirement than had previously been considered.

Joint agreement of BuAer, WADC and Bell Aircraft Corporation, regarding the integrated electronics for the Model 2000, was reached at a meeting on September 27, 1958 .

Frames for the forward electronics and forward engine compartments had been added to the airplane mock-up. Additional framing, aft of the engine compartment, was in work. The stabilizer mock-up was essentially complete, and the fin leading and trailing edges were in work.

Next is the October Progress Report dated November 15. According to Bell, the final draft of BuAer Specification SD-535-1, “Detail Specification for Model VTOL/STO-VL Airplane,” was signed by Bell on October 24, 1958.

Performance studies, based on preliminary General Electric J85-SJ120 engine data, were in process.

Theoretical results, to date, showed that the horizontal and vertical tail surfaces were adequate from the flutter standpoint.

Tests of the first transonic wing model had been completed, and work on the 1/6 scale flutter model was continuing. Additional test data were obtained on the jet impingement model with improved simulation of the forward fuselage and nacelle inlets.

Structural design criteria work had been essentially completed. The weight status remained unchanged from the previous reporting period.

The autopilot specification was coordinated with BuAer and WADC, and was sent to vendors for proposals.

Concepts of dispersed site operation were under continuing study. Evaluation of several methods for airplane quick- release tie-down systems was continuing.

New subcontract commitments included those for the hydraulic system, canopy, and avionics system (CNI, display, and the doppler inertial system).

Mock- up framing for the forward and center fuselage sections had been essentially completed. Work had been started on the nacelle center section and rotation joint. The master form for the windshield and canopy section was completed.

The November Progress Report has not been found, so we move next to the December 1958 Progress Report dated January 15, 1959.  By this time, Standard Aircraft Characteristics Charts and the performance data report were in publication. Wing flutter analyses showed stability within the airplane operational boundary.

Transonic tests of the 0.048 scale model were scheduled to start during January 1959. Supersonic tests in the Langley Unitary tunnel were scheduled to start soon after completion of the transonic tests. Work had been started on the construction of 0.07 scale horizontal stabilizer models and 0.08 scale vertical fin models for wind tunnel flutter testing.

Testing of the 1/10 scale jet impingement model was resumed during December.

Two coordination meetings were held with General Electric Company personnel regarding the autopilot system and air data computer requirements. Two integrated electronics team meetings were held during this reporting period.

The electrical schematic of the power generation system was being revised to reflect the dual 10 KVA generator system.

A proposal for continuation of the Model 2000 program through Phase II was prepared and submitted to AMC. Discussions with AMC were continuing, and contractual coverage at an early date was anticipated.

The five basic sections that made up the fuselage mock-up had been spliced together, and the wing had been attached to the fuselage. One specification mockup J85 engine had been received. The canopy and windshield mockup and the A3J seat mockup had also been received.

To view the documents and images in higher resolution, please click through the image gallery above.

All images from NARA Archives II, College Park, MD, RG 72

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