8 November 2007 Update

Frequently Asked Questions (FAQ)
2007/08 Competition Specific

Please check the FAQ often during the competition.  Please note that rules interpretation questions are not answered by e-mail until after the entry date (when all participant e-mail address are known), so that all teams will have equal access to all rules information.

*** All Rulings In This FAQ Supplement The Official Rules! ***

General Notes:

·        2.4 GHz ISM band radios are now legal for the contest.  They MUST be capable of implementing the full fail-safe sequence procedure outlined in the rules.  If you are going to use a 2.4 GHz radio please note it in the appropriate location on the entry form.

·        Brushless motors are now legal.

·        Ni-mH batteries are now legal.  Li-Poly batteries are NOT legal for use either as propulsion or RC batteries.

Payload Questions:

All payloads for this year will be provided by the contest administration.  Suitable payload definitions are given in the rules to allow teams to create their own payloads for testing.

1.     Question: Are the passenger collars used for a means of separating one another or are they for mounting purposes?
Answer: The collars will only be slipped over the bottles, they may not be secured to the bottles sufficiently for use as part of a retention system.

2.     Question: Can the collars of the passengers overlap?
Answer: No.

3.     Question: What is the ballast material (ie water, sand, other)?  Is the collar itself the ballast?  Will passengers that are heavier be identified?
Answer: The ballast will be water.  The weight of individual “passengers” will not be marked.  The collar is not part of the ballast.

4.     Question: Can you provide the exact size, shape and weight for the water bottle “passengers”?
Answer: The “passengers” may be comprised of any mix of commercial ½ liter water bottles.  They range from about 2.4 to 2.6 inches in diameter (61 to 65 mm) and 7.6 to 8.3 inches in height (194 to 210 mm).
Typical bottle shapes are shown in the attached figures.

"Passenger" with notional collar. Contest passengers will not be wearing glasses.

Flight / Mission Questions

1.     Question: Do we have to fly all of the different missions to get a score?
Answer: You will get a score for each mission you successfully complete.  The Delivery Flight must be completed before any Payload Flight(s) may be attempted.

2.     Question: Is there a minimum altitude for flying the course?
Answer: No. Altitude must be high enough for safe flight as set by the discretion of the Contest Director.

3.     Question: Can we tailor the configuration of the aircraft differently for the different missions?  For example, could we use different sized propulsion systems for each flight?
Answer: You cannot change the hardware configuration of the aircraft for the different missions.  You can however change the propeller diameter/pitch for each flight attempt.

4.     Question: At what wind speed will the contest be called.
Answer: It will be up to each team to determine whether they want to fly or not. The contest will be called if the wind speed exceeds 30 mph for a period of time sufficient to prevent all teams who are ready to fly from being assigned a flight time slot. The 30 mph limit is consistent with normal AMA competitions and is required to retain our contest insurance coverage.

5.     Question: For the rule requirement that the aircraft fit within a specified spot size, does the aircraft have to fit in this area fully assembled?  If so, does it also have to be flight ready or would something like folded, but attached wings be considered assembled?
Answer: It must be fully flight ready.

6.     Question: Is there a height limit for the aircraft to go with the spot size?
Answer: No

7.     Question: Is the “hatch open” payload test going to be done with holding the plane from wingtips, or from anywhere from the fuselage while hatch is open?
Answer: The airplane need not be held by the wingtips for this test, but can be held from any orientation that exposes the payload.

8.     Question: I have noticed that you have allowed the use of 2.4 GHz systems.  I currently own and work with these new transmitters and have found it to be that none of them actually have a full-fail safe system.  Mine, the Spectrum DX7 only has a fail safe with throttle only.  When the transmitter is turned off the airplane returns to engine idle.  Although I have flow my airplane over 50 times and not once got hit with a spike in signal or loss of control over various airports.  The system is virtually perfect.  What can we do about this system?  Are we still allowed to use this system or do we have to us FM bands only?
Answer: Not all of the 2.4 systems have the full fail safe feature that we require. Just like not all of the 72Mhz radios have a full failsafe.  The JR 9303 2.4 (http://www.horizonhobby.com/Products/Default.aspx?ProdID=JRP2910) has the full failsafe available.  The XtremeLink by Xtreme Power Systems (http://www.xtremepowersystems.net/index.php) also features a full failsafe option.  The Spectrum and Futaba 2.4 radios are throttle only.  To be legal for the contest a 2.4 radio MUST support the full failsafe sequence.

9.     Question: For mission one, do you have to be flying for five minutes or can you land prior to that?  Do you have to land within the five minutes?
Answer: You may end the mission prior to the 5 minutes.  The aircraft does not have to be on the ground within the 5 minutes.  The last lap COMPLETED within the 5 minutes determines the mission score.

Aircraft Configuration Questions

1.     Question: On the webpage it states that aircraft CANNOT be of rotary wing design. Rotary wing being somewhat defined in another section as 'vertical flight capability'.  However, thrust vectoring IS allowed, as are ducted-fan units.  Is vertical Take-off via ducted-fan units legal, or does that fall under the rotary aircraft definition?
Answer: A ducted fan configuration capable of thrust vectoring for short take-off but not true vertical flight would be legal.

2.     Question: We have talked with an outside vendor and they posses a manufacturing technique and material that we are not capable of producing here at the school.  The design of the part would be done by us, with manufacturing done by them..  Is this permitted by the rules?
Answer: No.  The rules (sponsor section) say “All design, analysis and fabrication of the contest entry is the sole responsibility of the student team members.”  Commercial components may be used if part of the manufacturers public product line.

3.     Question: Since the hatch holds no load can it be magnetically constrained?
Answer: The mechanical fastener requirement does not apply to elements of the aircraft outside the payload retention system.

4.     Question: Are gyros legal for stability purposes?
Answer: Yes

Report Questions

Report format rules are significantly changed from prior years.  Be sure to follow the current rules.  Being allowed in prior years is not grounds for expecting the same item to be allowed this year.

1.     Question:.
Answer:.

General Questions

1.     Question: Is it safe to assume that if the rules do not explicitly forbid something, it is allowed?
Answer: The rules are intentionally designed to not impose too many limitations while allowing each team an equal chance. If something adheres to the "spirit" of the rules it is likely to be allowed. If you have any specific questions you would like clarified they may be addressed in a private e-mail to the contest administrator. Ideas will not be disclosed to other teams if they represent a legal and innovative approach. If it is deemed to be not legal, it may be added to this FAQ or posted to the other teams at the administrator’s discretion.

2.     Question: What would constitute “non-critical” versus “significant damage” on landing as described in the rules?
Answer: The decision will be at the discretion of the flight line judges.  In general, “non-critical” damage would allow the aircraft to be easily returned to safe flight status. A couple of examples of “non-critical” damage would be a broken propeller, bent landing gear, sheared nylon bolts or minor scratches to the finish. If any component is structurally damaged and would be considered a hazard to safe flight then it will be considered as “significant damage”.

3.     Questions: Can there be thrust vectoring via rotating the engine, nozzles, blown surfaces etc.?
Answer: Yes. Any of the above options is allowed, and may be varied during flight. However, "rotary wing" vehicles are not allowed, so you may need to consult the judges with your specific design and it's thrust levels to be sure it doesn't cross over the line into vertical flight capability.

4.     Question: Do all of the team members need to be student members of AIAA?
Answer: Since the DBF is part of the AIAA competitions sanctioned by the Student Activities Committee and the AIAA Foundation, all team members should be student members of the AIAA.

5.     Question: What was the maximum number of people that can make-up a team.
Answer: There is no specific limit on team size. It is up to the team itself to determine a size sufficient to meet the required tasks and small enough to remain manageable. It is expected most teams would fall in the 5 to 10 member size range, but this is only an estimated guideline.
There is a maximum size of the flight crew (pilot and assistant) and ground crew (3) for this years competition. Please see the RULES section for more details on the limitations on the flight and ground crews.

6.     Question: Is it necessary to list all team members on the entry.
Answer: Yes, we need to know all the team members to verify the under/upper classmen rule. Teams will be allowed to revise/update their official membership one time in February.

7.     Question: What is meant by "Upper and Under Classmen"
Answer: Upper Classmen are (for purposes of the contest) seniors and/or graduate students. Lower Classmen are Freshmen, Sophomores and Juniors.

8.     Question: Does the 1/3 under classmen rule apply to the people present at the fly-off site?
Answer: No.  The 1/3 , 2/3 distribution applies to the team as a whole, from the entry date through the end of the contest.  Not all team members must be present at the fly-off.

9.     Question: Is it allowed to have/declare more then 1 pilot in a team (in case one of them can not go to the contest, or simply have a back-up pilot)?
Answer: Yes, teams may register multiple pilots as long as each meets the requirements listed in the rules.

10.                        Question: Can we have corporate sponsors? If so, can we put their logo on the UAV at any place that pleases them?
Answer: Teams may solicit and accept sponsorship in the form of funds or materials and components from commercial organizations. All design, analysis and fabrication of the contest entry is the sole responsibility of the team members.

Sponsor and university decals or logos may be placed as desired. Teams should make sure that the final color scheme of the aircraft provides good visibility of the aircraft location and orientation for the pilot.

11.                        Question: Our team has completed our design calculations and we have found a manufacturer that carries wing components that will meet our design criteria. Can we purchase components (i.e. foam cores and skins) to construct the wing for our UAV, or are we required to build it from scratch?
Answer: You may use unassembled components such as wing cores providing they are integrated in a way that results in the final configuration being an original design.  You may also have components of your design machined to your design specifications by an outside contractor if the team and/or university does not have the required machining facilities.

12.                        Question: How is the radio fail-safe described in the safety supplement to be implemented.
Answer: This is a feature available in many production RC radio systems. It is required that your radio system be able to provide this function.

13.                        Question: When you check the CG, what kind of a point will you use? For example will it be checked with fingers or dowels or something even sharper?
Answer: The CG check will be coincident with the structural verification test described in the Safety Requirements supplement to the basic rules. Specifically, two team members will be asked to pick the aircraft up by the wing tips using their hands (usually a clenched fist placed under the wing at the desired location works well). They will (gently) lift the aircraft at it's full contest weight by the wing tips at the marked axial CG location. For aircraft configurations where the CG is not within the chord of the wing tips, a third lift point, located as far from the CG as possible, will be used to balance the aircraft.

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