Tag Archives: wind tunnel

Farnborough’s Older Buildings

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In my days working in aerospace, I dealt with people at the RAE/DERA, but I never had any visits there. I went to the show, of course, and BAe moved the headquarters there and I spent plenty of time in those offices, but I never was on the government side of the site. Now it has been handed over to private developers, you can drive around the various buildings. Much of it is new development or refurbishment of old buildings.

There are some of the old facilities still there, though. A couple of wind tunnel buildings are in place – one of which has camouflage paint for some reason! There are plaques on the various buildings to give a bit of their history. I know of many test programmes that were undertaken in these facilities, and I believe they are still in use since some of the capabilities are still in high demand.

One smaller building is the remains of a water test tank. This was apparently shortened at some point and now the building still has the tank profile inside while the outside has the test rails but seems to have been filled in. It is good that so much of the original facilities is still there even as redevelopment has taken place. Sadly, I won’t get to experience what it was like when it was at its busiest.

High Speed Intake Model

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The FAST museum at Farnborough has an extensive collection of wind tunnel models – both low and high speed. One that caught my eye was one that an old colleague of mine had worked on. It was a high-speed intake test model for what would become the Typhoon. You might be familiar with whole airframe wind tunnel models that are used to assess the aerodynamic characteristics of a plane. However, there are many different types of wind tunnel testing that get carried out. Intake testing is one of them.

This model served a number of purposes. There is the more obvious one which is assessing the quality of air coming down in the inlets as the aircraft changes angles of pitch and sideslip. A rake of probes will be set where the front of the engine would be located and then the test programme can assess how distorted the flow is as the aircraft manoeuvres. This is then compared to test data on what the engine can accept before it starts to have problems.

The Typhoon has the two engine inlets side by side. This can result in a problem with one engine affecting the other one. If an engine surges, a pressure wave will come back up in the inlet, and this can then affect the flow into the other engine. This surge interaction needed to be investigated prior to the plane flying.

One less obvious test programme related to the testing of air data system inputs. Fly by wire aircraft are very dependent on the quality of the measurements of the aircraft’s pitch, roll and sideslip. As the aircraft changes its angles, the readings at the location of the probes need to be calibrated. Flight testing will refine this information, but you need to have initial data for the first flights before calibration can be demonstrated. The intake model is the one that was used to verify the flow field around these sensors. I’ve included a shot of the sensors on one of the development aircraft to show where they are.

This model was very important in the preparation of the Typhoon for flight test. Great to see the model has been preserved.