Frequently
Asked Questions (FAQ)
2004 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.
General Notes:
1. A
question was submitted asking if the Plattenburg “Graupner Style” motors are
legal for the competition. The answer is
No. Teams should make sure they have
documentation for their motor, preferably the purchase invoice(s) and the
manufacturers labeling should be easily visible to the judges during the
technical inspection. Teams may be asked
to remove their motor so the manufacturers label may be checked.
- We receive many questions
about using Ni-mH, or lithium batteries. We are well aware that battery
technology is making some significant improvements. We continue to monitor the capabilities
of these new chemistries (and use them in the UAV systems designed here at
NRL). While the other chemistries
offer improved energy density, and are making significant strides at
accommodating high current drains, they are still significantly more
expensive. For the present contest,
NiCad batteries remain the only allowed chemistry.
Payload Questions:
- Question: Are external
pods for carrying the cargo permitted?
Answer: External pods (wing or fuselage mounted) may NOT be used for carrying the payload. (rev 22Oct02) - Question: Does the internal water tank also have to be
fabricated from 2 Liter plastic soda bottle(s)?
Answer: No. The internal water tank may be of any construction as long as it’s capacity is 4 Liters or less (which will be verified during the technical inspections). - Question: Can we fabricate our own servo-controlled water
release valve or must we use a specific commercial component?
Answer: You may use a commercial electronically controlled valve, may fabricate your own servo controlled valve, or any combination of commercial and fabricated parts. - Question: Can we use a pump or pressurized tank to help EMPTY
the water tank?
Answer: No. The tank must be emptied by gravity alone. The sole exception is you may align the tank vent tube into the onset airstream, giving a very slight positive pressure assist. - Question: Can we have more than one water outlet?
Answer: No. The rules specify a single, round outlet with a maximum allowed diameter. - Question: Can the water tank(s) be
removed for the ferry mission?
Answer: No. The aircraft configuration for the ferry flight must exactly match the fire-fight configuration. For the ferry mission the tank MUST be empty. - Question: Can we use a pump to
assist in FILLING the aircraft with water?
Answer: Yes, you may use a pump that moves WATER to assist in filling the aircraft. You may not use a pump that compresses AIR and pressurizes the supply bottle to increase the filling rate. - Question: Is there a minimum
capacity of water the aircraft must be capable of carrying?
Answer: No. You may design the aircraft to carry less than the specified maximum capacity. - Question: Can we connect the soda
bottles together when using them to fill the aircraft? Can the outlet of the connected bottles
be larger than the outlet of a single bottle?
Answer: You can “connect” more than one bottle using any type of manifold/assembly you desire. The outlet of the manifold/assembly and the inlet of the aircraft are not regulated in size. You may not modify the soda bottle itself in any fashion, but you may modify the “cap” to accommodate your manifold/assembly. Also see the answer to Q&A #7 above. - Question: Can we swap out or
replace the aircraft’s internal tank between sorties instead of re-filling
it?
Answer: No. - Question: Can we seal the vent for
the water tank for the inverted lift test during the technical inspection?
Answer: Yes, you can seal the vent with a plug, tape, or other. You can also just leave it alone, as if the “outlet” is closed very little water would leak out when turned inverted for the short period of time of the test. - Question: Can we use a collapsible
or variable volume tank in the aircraft?
Answer: Yes, you may use a collapsible or bladder style tank as long as it is made from a non-elastic (ie. will not expand under pressure) material and it’s maximum volume does not exceed the allowed volume.
Flight /
- Question:
Does the ten minute mission window apply to one flight attempt (chosen
from
Answer: The 10 minute window is for a single mission event (A, or B). - Question: In the rules
examples, all the times are in round minutes. What accuracy will be used for
determining flight times?
Answer: It’s just to make the rules document cases simple. We will record times to the accuracy possible, probably to nearest second. - 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. - Question: How are the
turns made, and is there a set turn radius?
Answer: The turns may not be initiated until the turn judge raises his flag (for the two 180 degree turns), but may then proceed to be any turn radius and rate the aircraft is capable of. The 360 degree turn can be initiated anytime the aircraft is on the "downwind" leg and also may be any turn radius and rate the aircraft is capable of. - Question: In the
rules, it says that the flight time lasts "...until the aircraft
comes to a complete stop past the starting line at the completion of all
laps..." Does the ground crew have to return the aircraft to the
runway before the time is stopped?
Answer: If the airplane rolls off of the runway BEFORE reaching the starting line it must be returned to the runway to taxi or be carried to the starting line. If it rolls off of the runway PAST the starting line it does not need to be returned to the runway. - 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 administrators discretion. - Question: Can we tailor the configuration
of the aircraft differently for the Fire Fight and Ferry 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 could however run only 1 motor of a two motor aircraft for the Ferry flight, and run both motors for the Fire Fight flight, provided both motors and propellers are installed for all flights and you simply “shut down” one motor for the Ferry flight.
You can also change the propeller diameter/pitch for each flight. We will allow this “change” since it can be thought of as mimicking a variable pitch propeller and would be impossible for the judges to police anyway.
Report Questions
- Question:
For the “Testing Plan” section of the report in-flight tests are
required. Is there a point penalty
for not completing the in-flight tests?
Answer: To obtain the maximum points all information asked for in a section must be present. Point deductions will be determined by the judges based on provided-vs-missing information. - Question:
In the RAC is “motor controller” the same as “speed controller”.
Answer: Yes, the two terms could be taken interchangeably. - Question:
In the RAC do electric brakes count as a type of controller
Answer: Yes. A single servo or solenoid controlling air or hydraulic brakes would count as one controller. If a separate electric actuators are used for each wheel, that would count as two (or more) controllers - Question:
The RAC states: "A "V" tail is considered to be a Vertical
surface without control (5 hr) plus a horizontal surface with controls (10
hr), for a total of 15 hrs"
.How is the horizontal span of the V-tail applied under the
provision that: "A horizontal surface is a 'wing' if it is more than
25% of the span of the greatest span horizontal surface."?
Answer: For the “25% span” rule the horizontal projection of a V-tail will be used as the effective horizontal span. - Question:
Could you please define "control volumes" as stated in the
Rules, Design Report section, paragraph 5
Answer: These are the classic static control volumes, (Surface_area x Lever Arm)/Reference_length - Question: How will the maximum exposed wing chord
would be measured for a flying wing.
For payload considerations, it is stated that the
"fuselage" is the inner most 9" of semi-span. Does this also apply for the maximum
exposed chord measurement, or will the max chord be measured at the
centerline (if this is the largest chord length).
Answer: For “All Wing” configurations the maximum wing chord will be measured 9” out from the centerline or at the largest chord location that is MORE than 9” out from the centerline.
General Questions
- Question: 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. - 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. - 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. - 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. - Question: What is
meant by "Upper and Under Classmen"
Answer: Upper Classmen are (for purposes of the contest) seniors and/or graduate students. - 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. - 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. - Question: What is COB
in the submission dates mean?
Answer: COB - Close of Business: data must ARRIVE by 5 PM local time at the specified location. - Question: The contest
day is graduation. Is there any possibility of moving the contest.
Answer: In selecting the contest date we have tried to minimize the conflicts with graduation, finals, mothers day,... We can't miss all possible conflicts as each university is on a slightly different schedule. Moving the date earlier would greatly increase the risk of unacceptable weather, and further shorten the time available to design and build the entries (which will seem VERY short by then). - Question: We were
wondering if it wouldn't be easier to just send an official representative
from the competition to our school, fly our plane, and take down the
score. Then compare with all the other schools competing(they'd probably
be on home turf as well), and make the final decision that way?
Answer: The single site -vs- fly-at-home issue was discussed much by the contest organizers prior to selecting the current contest structure for many of the same reasons you raised. We realize that it is difficult for students to obtain funds for fabricating an entry, even without the added costs of travel. In the end we selected the single-site format for mainly two reasons: (1) the single-site format will allow the teams to see each others entries and learn from each other and will add to the competitive fever always present when pitting your best efforts against others; and (2) the single site is the only way to assure a level playing field for all entries, as weather variations at multiple sites and days would inevitably help some entries and hinder others. - 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 (and the rain date used) 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. - Question: Will a hard
runway be used?
Answer: We will select a site that provides a paved runway. Note that a "smooth" paved runway for manned aircraft may still seem "rough" for contest aircraft. - 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. - Question: Does the
plane have to be an external propeller plane, or can it be a duct fan UAV?
Answer: Ducted fans are also legal if they use a commercial fan assembly. - Question: In terms of
propellers. Can they be any kind of Gas engine propeller if we wish? Or do
they have to be Electric motor propellers? And if we can only use electric
motor propellers, can we cut them? Basically, if we wish to, can we use
any kind of non-electric motor propellers if they are commercially
available?
Answer: Any commercial propeller for either gas or electric models may be used. Props may be cut to reduce their diameter but the blades may not be reduced in thickness (such as by sanding the airfoils to a new profile) or in chord (such as by trimming the trailing edges). - Question: What
constitutes "over the counter" batteries, and does this apply to
the battery pack or to the individual cells?
Answer: The "Over the Counter" refers to the individual cells. This is a change from the rule for the 1996/97 contest year. - 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. - Question: Can we construct
a composite can for an otherwise stock over the counter model motor?
Does the motor controller have to be an over-the-counter controller?
Answer: The motor and/or controller must be an unmodified commercial product. The intent of this rule is to prevent excessive cost, and to provide all teams access to equal propulsion technology so they can concentrate on the aircraft aerodynamics and structural aspects. - Question: Do the
wires and connectors have to be commercially available?
Answer: Yes - 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. - Question: Will the
payload be supplied by the team or the contest administration?
Answer: By the team. - Question: If battery
power fails can an immediate landing be made without making a complete lap
(question paraphrased by editor)
Answer: First priority is safety of personnel, followed by minimizing damage to facilities and equipment. If power fails unexpectedly the pilot will setup for as safe an emergency landing as possible. If the plane does not pass the downwind pylon that sortie's payload will not count, but any prior sorties will still be credited toward the overall score. - Question: Will there
be a maximum altitude, other than the visibility requirement?
Answer: There is no specific numerical altitude limit. It would be very difficult to enforce a rigorous altitude limit without altitude telemetry equipment on each aircraft which would be a significant expense burden. The contest flight judge will enforce maintaining a "safe" altitude for both personnel/ground and flight visibility reasons, and may order the pilot to descend if he feels the altitude is too high. In general, altitudes of 300 to 500 feet are probably nominal, and altitudes near 1000 feet are likely to have the judge order a decent. - Question: Would we
ever have to make any vertical loops with the UAV?
Answer: No
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