Subject: DBF Q&A #1
2004 DBF Q&A #1
3 Nov 03

There have been several versions of questions all asking in essence the same things which are paraphrased below.

Q: How many dump holes are we allowed?
A: One (1) with a round internal cross section a maximum of 1/2" in diameter.

Q: Is there a minimum water capacity that the plane must be capable of carrying, or that must actually be carried on a flight?
A: No

Q: When on the flight can the water be dropped?
A: Anywhere on the "downwind" leg.  The "downwind leg" is defined to start when the flag man lowers his flag as the plane exists the upwind turn and ends when the flag man raises his flag as the plane enters the downwind turn.  The "downwind leg" includes the 360* turn.

Q: Can we use a Venturi device to increase the rate of water flow through the exit orifice?
A: Maybe. 

You may locate the exit orifice anywhere on the airframe that you wish, so you may locate it in a local area of low pressure.  There is no restriction on the fuselage shape or local contours (which may or may not produce local pressure variations). 

You may not use a separate "Venturi tube" type of device with the exit inside the tube.  To determine if it is a "legal" outlet location, the orifice must be clearly visible when looking straight up at the under surface of the aircraft.

Q: Is there any restriction on the size of the fill opening in the fuselage?
A: No.  You may use any fill opening, you do not have to "back-fill" through the dump orifice.

Q: Is there any restriction on the size/location of the tank vent tube?
A: No.  Please see the FAQ item on using flight speed ram air to assist the vent tube (which is the only legal "pressurization" of the on-board tank.

Also, I had several of the welcome e-mails return due to bad addresses.  Please make sure that both your team contact address and your advisor's address received the welcome e-mail (and this e-mail) and send me any corrections.  Again, be sure all contest email has DBF in the subject line, and you include both your university and team name (I don't plan on searching through the e-mail address list to see which team you are).

-Greg
Gregory S. Page
ITT AES B210
2560 Huntington Ave
Alexandria, VA 22303
202-404-1251
202-767-6194 FAX

Contest web page: http://www.ae.uiuc.edu/aiaadbf/  ** NEW ADDRESS **