CONTEST EMAIL ARCHIVES
Date: 03/14/2007
Subject: TARC Deadline is Approaching!
TARC Teams:
The deadline to submit qualification scores is quickly approaching! There are 3 things you need to know:
1) By March 15 your team should make your first qualification flight attempt in front of a NAR Senior member observer. You must make your final qualification flight attempt no later than Sunday, April 8th! The top 100 teams (announced on Friday, April 13th) will be selected on how close they come to the goals of the contest.
2) Due to the high volume of specific rocket motor questions we have added the following question to the FAQs on the website:
Q: The motor that I am interested in using for my TARC rocket has a slightly different manufacturer-labeled designation or total impulse than the motors on the TARC Approved Motor List. Can I still use it in my TARC rocket?
A: For purposes of determining if a motor is approved for TARC, only three things count: the manufacturer name, the labeled total impulse class, and the labeled average thrust designation. Some manufacturers, particularly Aerotech, have other additional labelled designations such as "W", "FJ", "Econojet", etc . The Aerotech letter coding is a proprietary indication of propellant chemical formulation and the extra words are just brand names. The codes that count for our official purposes are the first letter ("E", "F", etc.) which indicates the motors's total impulse class; and the one or two digits before the dash ("23", "24", etc.) which indicate the motor's average thrust in Newtons.
The final digit or digits after the dash in a motor's official designation indicate the motor's delay time between motor propellant burnout and ejection charge activation, in seconds. There are a few cases where the value we list for delay time on the TARC list is not the same as the delay time value that the manufacturer advertises in his catalog. This is because the motor delivered a different delay time (generally by one or two seconds) in the NAR's official certification testing, after the manufacturer printed his catalog. We allow such motors for use in TARC despite this minor delay-time marking discrepancy.
Concerning total impulse, some Aerotech motors were slightly redesigned for ease of manufacture in the last several years and their total impulse post-redesign is slightly different from the original design. Both old and new-design motors are in circulation. The TARC motor list reflects the original-design total impulse of these motors; we do not yet have official NAR data for updating the total impulse. It is important to teams to know the correct total impulse of the motor they intend to use, but either version is approved for use in TARC as long as the three key factors on the motor label match what is on the TARC motor list.
3) Please log in to your team information page (using the link and password in Step 6 of your Confirmation Email) and check to see if the list of students on your team is correct. You may not add or drop students from your team after your qualification flight! So make sure you fax all changes to 703-358-1133.
As always, please contact us at rocketcontest@aia-aerospace.org with further questions.
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