This page contains a Flash digital edition of a book.
FOSSETT LSR


Rear view showing off the wider track and structural changes to the rear suspension and parachute fittings as well as the revised wheel fairings


that Craig Breedlove’s own 2014 project is a twin-engine design.) One of the first areas that


Ahlstrom’s team focussed on was what they felt caused the 1996 crash. ‘Looking at the data from the tests we decided we would have to look at the steering system and the steering geometry,’ he explains. ‘It seemed to us that this is what caused the issues at Black Rock. So to test the steering we simply hauled the car out into the parking lot and pushed it at a whopping 5mph. It didn’t steer. It was completely unstable. So we re-designed it until it was stable and self-correcting. On top of that, we found and fixed five other flaws that would have caused an accident at over 700mph. That was probably the most


the test programme, and the first thing on the schedule was low-speed testing of the steering and braking systems. We would run in increments starting at 200mph and working our way up. At each increment we would have tried to turn the car. We had equipped it with GPS, attitude, accelerometer and wheel load sensors and we would rapidly turn the car from side to side with the response of the car vs the demand of the driver monitored. If there was an instability, we would hopefully find it at low speed before finding out at high speed, as Breedlove did. It is funny because in land speed racing nobody seems to test the steering – just mentioning this part of the test programme to other teams alarmed them. They


“It is funny… in land speed


racing nobody seems to test the steering”


extensive and difficult part of the project. We were proceeding down a path and we thought we had something that was working but, when we got into it, we discovered it was not working and we had to back right up. ‘Around the time of Steve’s death we were about to enter


just presume that as the car is going straight that everything is fine. Had Thrust SSC not had steering issues they would not have done steering tests either.’ When Breedlove lost control at


Black Rock, many put the problem down to aerodynamic instability, and it was no surprise that the


10 www.racecar-engineering.com • January 2012


The cobalt-chromium ‘Flintstone’ skid brake proved good for -0.26g at any speed. Note there is almost no wear after 20+ runs


Fossett team made substantial modifications to the bodywork of the car with that in mind. But Ahlstrom maintains that actually aerodynamics were not the root cause of the issue: ‘The idea of an aerodynamic instability was absolutely preposterous to us. Everyone outside the team thought it was an aerodynamic issue, but CFD was performed in late 1996 that showed no lifting of the back end and that the design was highly stable. The whole concept is focussed around drag vs stability, which is quite unlike any other competition car. Everywhere else designers are restricted by rules that are trying to keep the car slower and slower, until you reach a point like they have in F1 where all of these tiny things become critical. If you


look at the aerodynamics for a road vehicle they will focus on downforce to generate traction and, as a result, there is not a single aerodynamically stable vehicle on the road today. At 1000mph we don’t have that traction requirement, the only thing we have to do is go straight and not fly!’


AERODYNAMIC RE-WORK With this in mind, the aerodynamic re-work of the Fossett LSR gave rise to a very different looking vehicle, somewhat reminiscent of the never-built Bluebird CN8. ‘The vertical stabiliser that was on the car originally was well forward of the rear wheel fairing, and the stabiliser is only as effective as its area multiplied


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  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100