Part 1: Deadline Wednesday 20: in my mailbox / e-mailed to me. No extensions; no excuses unless there is some major unpredictable event, in which case you should let me know ASAP. You need to be ready for that test on the 13th. Get moving quickly, please.

1. Announce your design team (who are the 2 people in your group?), your aircraft's name and its overall capabilities and the kinds of missions for which it is being designed.
  (what range, speed, altitude, how much payload,  one engine or two?)

2. Create web pages for your aircraft's design on your GT web page (discover how to do that), its OK to post the same on the web pages of both team members at this stage. Don't waste time on fancy gizmos: just post the basic information.  E-mail me the links to your pages so that I can post them next to your e-mail address on the AE1350 page.

3. Decide the gross weight of your aircraft, as discussed on the previous assignment sheet and in class: either a single-engined fighter of the 20000 to 23000 lb class, or a 2-engined fighter-bomber in the 60000-70000 lb class.

This is your "T.O.W."  or "W" for short, in the following:

4. Decide what wing loading to use (see other modern fighters in that class of missions/ weight range for guidance).  This is W/S.

5. From this find the wing planform area  S.

6. For the single-engined craft, the wing span is limited by the need to hide under a highway overpass: (please check the tail clearance as well,)  and limit the wing span to 30 feet.

  For the 2-engined aircraft, the wing span is limited to that of the F/A-18.

7. Find aspect ratio (AR)

8. In this fighter design, we need to check the requirements for several "design points" to see which demands the most powerful engine. The first such point  (selected for ease of calculation at this stage) is:

a) Design Point #1: Loiter at  5000 meters or above, at standard altitude, at Mach 0.3 or less.

a.1 Find the wing lift coefficient C_L needed to produce enough lift to support the weight of the aircraft under this flight condition. Note: use the Mach number and the speed of sound at 5000 meters  to find the flight speed. Use the density at 5000 meters, and the wing area S.

a.2 From this, and assuming that the "Spanwise Lift Efficiency Factor" is 0.98, find the Induced Drag Coefficient, C_Di.

The total Drag Coefficient is  C_D. = C_Di. + C_D0

Where . C_D0   is the "profile drag coefficient", here taken to mean that part of the drag which is there regardless of whether any lift is being produced.

For this aircraft,   C_D0 = 0.023 at low Mach numbers.

a.3 Find the total drag coefficient, and hence the total drag on the aircraft. To fly straight and level at this condition, this is also the Thrust Required. Note this result as well.

a.4 Given that the lift curve slope of the wing is 4.3 per radian  in this low-Mach number regime (pretty terrible, but then its designed for other conditions), and the zero-lift angle of attack is -4 degrees,  calculate the angle of attack needed to fly at this condition.

a.5  Use Excel. (Or the IBM Big Blue: I don't care).  Vary the flight condition (altitude in increments of 1000 meters,  Mach number in increments of 0.02 from 0.4 downwards) and plot the thrust required, the angle of attack, and the lift and total drag coefficients as functions of Mach number for various altitudes.

a.6  Also plot the lift coefficient and the Total Drag as functions of speed, speed in meters /second. Identify if there is a point of minimum drag in this region. If so, discuss why this occurs. (How can drag be miniumum except at a speed of zero?)

a.7  Identify the limiting lines where the angle of attack reaches 30 degrees (stalling angle of attack for this design for the present).

a.8 Identify the altitude where this limiting angle of attack is reached even at Mach 0.4.

Note: the above calculation assumes that even if the angle of attack reaches 30 degrees, the thrust has no component acting vertically. This is OK at this stage: we will explain this as being the result of having thrust-vectoring.

a.9  From the above, decide what is the thrust required at the highest altitude where you can loiter  at Mach 0.3

a.10. If this altitude is not even 10,000 meters, well, we'll have to change something, won't we?  Reduce the wing loading and start all over again. This is the beauty of using Excel, etc.  When I was a student, this would have meant another 3 days with a slide rule, with much frustration at the numerous errors I used to make (before reaching present state of perfection, that is).

1. An airplane has wings and tails as shown below. The  lift curve slope is 6.0 per radian for both the wing and the tail, and the zero-lift angle of attack is zero for both (symmetric airfoils used, with no twist, whatever that is). Neglect any effect of the wing on the tail.

Given the following facts:

a) the wing area is 4 times the tail area,  because the chord of the wing is twice that of the tail, and the span is twice that of the tail, and both are simple rectangular planforms,
b) the center of pressure of the wing is at 0.25 c from its leading edge, and likewise, the center of pressure of the tail is 0.25 c from its leading edge.
c) The distance from the tail c.p. to the center of gravity of the aircraft is 8 times the distance from the wing c.p. to the C.G.

Find the angle of attack of the tail needed when the wing is a 5 degrees angle of attack, to keep the aircraft stable.

If you need these (and I am not thinking about whether you really need them, but you really should):

The aircraft is built by UGA Buffalo Wings Inc.
The engines are built by Gator Marsh Gas Engines, Inc.
The aircraft weight is 70,000 lbs.
The aircraft is flying at Mach 0.3 at 20,000 feet standard altitude.
The wing loading is the same as that of a Lockheed P-3 Orion in cruise configuration.
 

2. The Planet Adminz (Now it can be revealed for the First Time) has an atmosphere surprisingly similar to Earth's. The composition is:

15% Oxygen ( O₂)
65% Nitrogen  (N₂)
10% Hydrogen  (H₂)
10% Carbon Monoxide (CO)

See the "Space Science" page on ADL for an explanation of what this is, and a bigger version of it.

a) Find the molecular weight of the "air" there. Note: the Universal Gas Constant is respected there too, as is Newton's Law of Gravitation and all other Laws of nature that we know here.

Surprisingly, the air gets hotter as you go up above Adminz. Thus, at sea-level on a standard day (the oceans themselves are 99% carbonated water and the rest is Secret Formula), the temperature is 220K, but rises at a constant rate to 350K at 10000 meters and remains constant for the next 100,000 meters. The pressure at sea-level is a nice 100,000 N/m₂.

b) Find the density at 5000 meters.

3. A space booster has an initial velocity of 100 meters per second, straight upwards. It has a weight of 5 million pounds, and thrust of 7 million pounds. Its mass is decreasing at a rate such that the specific impulse is 350 seconds.

Using the FULL statement of Newton's second law, (i.e., include the rate of decrease of mass in your calculation) find the acceleration, and assuming all things to hold constant for 0.1 seconds, find the velocity at the end of 0.l seconds.  How much difference does it make if you do not include the mass decrease term at all?

4. More to come here.....