Feature Aerospace, military & defence
happen in a single-cycle timed loop, so the pipelining technique was used to meet the requirements of single-cycle loops. Instruction n+1 had to be read while executing instruction n – so the next instruction had to be read at the same time the current one was executed. However, if instruction n is a branch
instruction, the next step is not n+1, but some number defined by the state- ment’s parameters, such as m. After any branch instruction, an extra iteration of the loop in which no instruction is exe- cuted has to be forced while instruction m is read. For this reason, the no-op instruction was added. Every time the code changes it takes
45 minutes to compile it before the change can be tested. However,
Seals for a military aircraft
When it needed replacement seals for the ‘kneeling undercarriage’ of a Hawker Siddely Andover aircraft, Saywell International turned to DP Seals. Built in 1965, this twin-engine turbo-
prop military transport aircraft has a kneeling undercarriage that allows the fuselage to be lowered for unloading vehicles on uneven ground. Kneeling is carried out by transferring oil from the undercarriage second stage oleo shock absorber into the main hydraulic system. The reverse is carried out to stand the aircraft back to flight position prior to take-off. To meet the requirements, DP
produced precision seals from old drawings. The company uses a transfer moulding process which enables short prototype runs and volume production.
DP Seals T: 01202 674671 www.dpseals.com
Enter 222
because the processor code was written in LabVIEW FPGA, it was quickly converted to LabVIEW for Windows for development and testing, saving man-hours. An additional benefit was the ability
to make a graphical programming environment after they had the Windows-based emulator. The program could be display in an easy-to-read table and had a complete set of debugging tools including single stepping, break points, and probes. It is possible to watch in detail as each program executes and quickly debugs the FPGA- based processor module as well as the actual text-based programs. Next, the digital outputs were stored to digital waveforms and these
displayed in a digital waveform graph. By using CompactRIO, the aging
system was replaced and a complete compiler and programming environ- ment developed. Full flexibility enables the system to be changed as needed. The system will be developed in the future to control new and larger detectors.
National Instruments T: 01635 523545
Enter 221
Authors: Eric Lyness – Mink Hollow Systems David Rapchun – Global Science & Technology Inc./NASA Goddard Space Flight Center Alexander Kutyrev – University of Maryland/NASA Goddard Space Flight Center
Project helps to protect aircraft from lighting strikes
On average, commercial passenger aircraft are struck by lighting once a year, sometimes result- ing in delays for inspection and repair. Modern aircraft, however, have increasing amounts of lightweight composite materials, making them susceptible to direct damage at lighting entry and exit points, and potentially to indirect energy coupling effects into the electrical systems as current flows through the aircraft. It is therefore necessary to accrue data on actual in-flight strikes to understand the nature of the threat. So, Opera electromagnetic design software
from Cobham Technical Services is being used as a final element of the company’s work for the ILDAS (In-flight Lightning Strike Damage Assessment System) project. This project was conceived to develop an in-flight embedded system for measuring actual lighting strikes. The software was used to predict the lightning strike current flow patterns on structures with carbon fibre composite materials, helping ILDAS partners to select the best locations for sensors, then to compare current flow predictions against actual measurements. For this, Cobham Technical Services generated
an electromagnetic design model of a specific airframe configuration for an EC135 helicopter using CAD files from the Eurocopter. This part of the exercise mainly involved simplifying non- critical parts of the original design data to min- imise simulation times, while maintaining good
Powering flight and command computers Amplifiers for test flight applications
NASA has selected wind River VxWorks 653 as the real-time operating system for the flight and command computers in the Ares I and Ares V vehicles. This will be the cornerstone of the Instrument Unit Avionics (IUA), providing guidance, navi- gation and control capabilities. Ares I is a crew launch vehicle
Compact, light, yet rugged, Endevco’s airborne amplifiers are for use in demanding flight test applications. These operate from an onboard
for NASA’s Constellation Program and is the core of a system that will carry crewed missions to the moon and solar system. Ares V is a cargo launch vehicle.
Wind River www.windriver.com Enter 224
22
aircraft DC power source and are designed for use with piezo- electric microphones and accelerometers. The 2680M-XXX is a
charge amplifier with dual outputs, one biased and the other unbiased, both of which are adjustable. Model 2685V is a voltage amplifier for use with ISOTRON (IEPE) accelerometers,
www.cobham.com/technicalservices
representations of critical elements such as metal space frames and surface panels, carbon compos- ite panels, electrical bonding and cable harnesses. Once the model was ready, the simulation took
a little over a day to run on a PC. Real-life tests at Eurocopter’s Munich facility showed that the theoretical predictions of energy diffusion effects agreed very well with simulation predictions. “These real-life tests of ILDAS's embedded
monitoring system concept illustrate how airframe-specific lightning protection can now be accurately evaluated and optimised during the design cycle," said John Simkin of Cobham Technical Services (Vector Fields Software).
Cobham Technical Services
T: 01865 370151 Enter 223
providing a constant current power source to the transducer’s integral electronics, while maintaining a two-wire connection. Both units have a microcircuit construction. According to the company, the units have an output voltage proportional to input acceleration or sound, and amplifier sensitivity is not significantly affected by input cable capacitance.
Endevco www.endevco.com
MARCH 2010 Design Solutions
Enter 225
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60