by Mina Cappuccio

July 14, 1999

Hello,

I am Mina Cappuccio. I am the NASA research engineer on the low speed test of the High Speed Civil Transport (HSCT) Technology Concept Airplane (TCA) model. This is the fifth and last test in a series of tests with this particular model.

A little history:
The first two tests were done in the 14' by 22' wind tunnel at NASA Langley Research Center. The TCA-3 test was done in the Twelve-Foot Pressure Wind Tunnel at NASA Ames Research Center in 1998. Aerospace Team Online has a series of journals about this test at http://quest.arc.nasa.gov/aero/events/test.html. The fourth test went back to the NASA Langley Research Center.

If you recall, the TCA-3 basic low speed performance test tested a number of leading edge flap configurations with some additional flow visibility tests including pressure sensitive paint.

During the TCA-4 test at NASA Langley Research Center, they tested three different wing planforms. A planform is the shape of the airplane from above or below. See http://quest.arc.nasa.gov/aero/events/collaborative/help.html. The way they changed the planform was to change the wing tips. On the TCA model the wing is in two parts, the wing spar and the wing tips. They tested three different wing tips. The baseline tip was used in the first three tests, and they also tested two other wing tips that had different wing sweep angles. In that test they were looking at the effect of different planforms on the low speed characteristics, (landing and takeoff configurations) of the airplane. Another thing they tested was a canard on the forebody of the model. Canards are put on for stability and control in low speed flying. In this case, the canard was placed at mid-mount, or at the mid-point of the height of the fuselage. They also tested different flap angles.

TCA-5 Test Objectives
One thing that is important to understand is that the 14' by 22' wind tunnel is an atmospheric tunnel similar to the 40' by 80' wind tunnel at NASA Ames Research Center. This is to say the test was done at an atmospheric pressure of 14.7 pounds per square inch, psi, or in terms of dynamic pressure, 85 pounds per square foot, psf. The 12-foot pressure tunnel can test up to 6 atmospheric pressures.

In this test, we will be looking at planform effects on the low speed characteristics of the airplane using higher Reynolds Numbers. We will use the baseline wing tip and one of the other wing tips tested in TCA-4. A second objective for this test is to look at some different and new leading edge devices on the aircraft. In this test we will test a mid- and high-mount canard.

All of these objectives will be tested at one atmosphere and at 3.7 atmospheres, two different pressures. The type of data we will be collecting includes forces, pressures, and flow visualization.

We are going to do two different types of flow visualization. One type is called a surface flow visualization using an oil. During the TCA-3 test, they tried to do color oil flow visualization which didn't work very well. This time we will use a different method. The model is in the prep room now. They are painting the surface of the right side of model white. The oil mixture we plan to use is black so it should leave black streamlines on the wing. We will use a digital camera to capture this information.

The technicians are painting the right side of the model black for an off body flow field survey. We will be using a technique called laser smoke screen. We will be injecting smoke into the tunnel and shoot a laser beam on to the model and, with a video camera, we will be able to track the vortex off the canard. In TCA-4 the vortex went inside engine producing and undesired effect. We hope the high mount canard will change this effect.

This is my first High-Speed Research low speed test. I look forward to sharing the fun with you.