CURRENT NEWS/Team Weekly BLOG
Updated: January 24, 2008
1/24/09: Happy (belated) New Year everyone! Big news and accomplishments from the beginning of 2009.11/03/08: And now the Blog is back on track! Please enjoy this most recent update provided by Jarryd!
Welcome back ladies and gentlemen to the weekly highlights of your own
CUDBF! Already done with PDR, CUDBF is getting ready to tackle the
tough opponents that are charging down the field this week. After their
short bye week, they are ready to sit back down and get back to work.
We begin our show with a glance back at the matchup with the PAB...
A quick play by play shows that many members were impressed by the
tough stand the analysis that the team went into took. Also, yards were
gained by the prototypes of the release mechanisms that were described.
However, many comments on the DBF telemetry system and the lack of
testing ideas and plans show the weaknesses in the DBF offensive line
and special teams. The defense needs to worry about that wingtip-hinge
design that the PAB capitalized on during the presentation.
The propulsions team coordinator Ross DeFranco has already selected and
purchased the motors for the aircraft (specifically Neu 1107 2Y type
engines) along with two different types of gear boxes. While the team
waits for the engines to come, last years engines, which are a very
similar model, will be tested with the gear boxes (4.4 and 6.7) to
determine which one will give the performance needed for flight. Ross
is also going to begin static thrust testing, and has also ordered 120
batteries to begin testing and soldering the packs. This should stack
up well for DBF going into next week.
Head special teams (i.e. aero) coach Shivali Bidaiah and the aero team
have sprung into action by finalizing the aircraft geometry (hopefully,
at this point!) by changing the sweep angle to 23 degrees to help the
aircraft fit into the box. This dedicated group is now beginning CFD
analysis, sizing the controls, and examining wing twist. They also hope
to examine wingtip stall from the CFD results, and build a scale model
of the aircraft to test in the wind tunnel. Really exciting news for
DBF.
DBF's high scoring offense (missions team) headed by Ben Kemper is
right in the middle of designing the mechanical and magnetic release
mechanism prototypes, and will begin actually building these this week.
They will also inspect how the aircraft will fit in the box. Really
promising for a strong offense to be so motivated late in the game.
The backbone of the team, the structures defense coached by Mark
Findley, is testing its indomitable strength by putting landing gear
into the Instron machines, testing the material properties, along with
foam/balsa blocks to determine their strength. SolidWorks is also
giving the team an FEM analysis of the structure, and much more testing
and analysis of the wing-hinge design are being performed.
Finally, Brett Miller is heading the avionics group that will be
looking further into the EagleTree telemetry system used to gather
in-flight data. The team is also concentrating on transmitter and
receiver selection, and awaiting the control surface sizing in the aero
team to select servos for the aircraft. Overall, an exciting week of
preparation leave everyone on their toes for how this team will perform
in the coming week. A lot on their plate, but the team is going to pull
through with a huge win this week.
-Jarryd Allison
09/08/08:
This week, DBF made progress on organizing the team and developing the
overall team goals and objectives. Our main goal is to enter and
compete in the AIAA Design/Build/Fly competition. Our personal reach
goal is to not only compete, but to take first place. Although the
project is not a failure if first place is not achieved, our goal is to
do our best to reach it. We will design an electric powered, R/C fixed
wing aircraft capable of carrying a 4L (water) simulated fuel tank with
4 wing mounted stores (Estes rockets). In one mission, the wing mounted
stores must be individually detached from the aircraft on the ground.
This years scoring focuses on aircraft weight and aircraft assembly
time. The aircraft and all flight components (payload, transmitter)
will be stored in up to 2 containers (maximum dimension: 2'x2'x4').
These will be weighed and become the rated aircraft cost (RAC). The
aircraft will then be assembled and the total assembly time factors
into the safety complexity factor (SCF = 1/RAC/Assembly time). This SCF
will factor into all three flight missions. First mission requires
flying 2 laps without payload and the score is SCF/Flight time. The
second mission requires flying 4 laps with the 4L full tank and the
score is SCF. Finally, the third mission requires flying 4 laps with
the wing mounted stores. Before flying the mission, the stores will
have a timed loading phase. The score for the third mission is
SCF/Loading time. Our goal is to optimize our design process in order
to maximize our score to become the winning team for DBF 2009.
-Dan Colwell
09/20/08:
Hello everyone to the 2008-2009 CUDBF team website. My name is Mark Findley, and as the new team's Webmaster I will be updating the website from here on. The site was originally designed and maintained by Stefan Elsener, a long time member and contributer to CU's DBF team. I hope I can carry on the task of maintaining the site well. If you have any questions or suggestions about the website, please feel free to contact me by email and I would be happy to give it a read.
-Mark
Mark as (Webmaster)
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Stefan as (Webmaster)
12/7/07:
Sorry for being light on updates... Thanksgiving week we had a successful first test flight. We found some minor issues with control surface sizing and propulsion components but for a first test flight we were 100% successful. We made the take off distance of 75 feet easily at 2/3 gross weight. You can see the video here. If weather permits we hope to get some more flying in before the end of the year so keep tuned to e-mail updates. CDR was presented on Tuesday and went pretty well. To wrap up the semester we will be doing some work on the payload system. Some payload rule clarifications came out this week that require retuning our restraint system. As always e-mails will be sent out about exact times and places.
11/13/07:
This week we received sponsorship from two companies in the way of Propulsion components. We want to thank Diversity Model Aircraft for offering discount Motors. We also want to thank Pro-Match Racing, who we have worked with the last two years, for providing discount matched, high performance battery cells. These companies links will be posted on our website for the remainder of the year for their generosity.
11/12/07:
Here is the update for last week and
plans for this week.
Update: Everyone is moving ahead with the critical design choices that must be
made. Propulsion is fairly set on a motor, and are working on getting test data
to validate their theoretical predictions from Ecalc. This is something that
the PAB and the contest graders will really like to see, so good work.
Structures has determined that Ansys is somewhat OK, but their MATLAB models
are working well. They have predicted less than an inch of tip deflection while
in flight, which is excellent. These models will be compared to actual wings to
validate the models. Avionics is still working on an angle of attack sensor for
us to use, and they are working with Eagle Tree Systems to get us a sponsorship.
Aerodynamics finished wing geometry and are working on stability and tail
sizing. They found that the plane is slightly unstable in a short-period mode
and a dutch roll mode, but ever so slightly. The instability is within error
for calculations, so it will likely not be a problem. They also found that the
plane needs just a very small vertical tail to be stable, and may not need one
at all.
We also have been making progress on the prototype. Josh was in over the
weekend to work on some methods for sheeting the wings. This is good progress
for testing how to make the wings.
Plans: This week is incredibly busy, we have but one week to get a flying
prototype by Thanksgiving. The analytical work for this model
is mostly done, and building is happening. If you have time this week, pop into
the lab and lend a hand. Aerodynamics is going to size the tail and control
surfaces, propulsion is going to get some test data and order components for the
final airframe, structures is going to work on validating their models and
helping build, fuselage is going to lead the building effort this week, and
avionics is going to get the telemetry system for us.
There is a lot of work to do, but we can do it. This is our only chance to fly
this semester, so let's not waste it. The prototype did not make enough
progress last week to get into a flying state, so if we want to make
Thanksgiving, we need to work hard and work fast to get this done.
Here again is the weekly update and plans for this week.
Organizational Changes:
The materials selection work has been moved to Fuselage in order to relieve
structures' workload.
Update:
Last week we got a lot done. Fuselage build a
prototype of the flying fuselage and the payload bay. They tested the
airbag restraint system, and it worked very well! There are still some
kinks, but the concept is there. The flying prototype is the first step to
getting a full flying prototype. They also have been working on gear
placement and vertical wing location for takeoff. Speaking of wings, aerodynamics
really worked hard to get the wings sized and airfoils chosen. Most of
their trouble came from trying to determine the proper neutral point location
(neutral point is the point on the aircraft where pitch moment doesn't change
with respect to angle of
attack). This is very important for aircraft stability, if the center of
gravity is not ahead of this point the right amount, the plane isn't
controllable. They figured this out, and are waiting on the systems
engineer to provide a more accurate estimate of weight so they can finalize the
incidences on the airfoils and the wing sweeps. Propulsion worked on testing
the thrust of a motor with and without fuselage interference, and found there
was about a 10% increase with no fuselage. This is a significant amount
of thrust and validates our choice to put the motors on the wings. Structures has finished their numerical models and are
waiting on information from aero to get
numbers from the models. They have also been working on how to build the
aircraft so that it is light and strong, and are moving towards that goal
rather well. Avionics has been talking to Eagle Tree Systems, a
commercial telemetry system maker, about sponsorship, which is progressing very
well.
Plans:
The aerodynamics team is going to finish wing sizing ASAP and move to control
surface and vertical tail sizing this week. The goal is to finish that
this week in order to build prototype wings. Structures will continue working
on their models and begin building some test articles to learn how to build a
foam-core wing. Propulsion is going to get batteries ordered and decide
on components and get those ordered so that we can get the propulsion set-up
tested. Fuselage will be working on landing gear placement and material
selection for the aircraft. There isn't a lot written here, but its a lot
of work, and represents the bulk of the remaining design work.
Update: Last week was pretty crazy, we made another design
change so that the front wing is on the top of the fuselage. This will
reduce landing gear size, weight, and drag. However, after a lot of
heated discussions, we made this decision. From there, we moved to span
optimization. Right now it looks like a 5 ft span was the correct
solution, but structures and propulsion need to finish their parts. This
was the main focus of the team last week.
Plans: This week there is a lot to be done. The span optimization
needs to be done so that every team can move forward with designing.
Aerodynamics will be working on airfoil and incidence selection.
Structures has a pretty good MATLAB model going, they will continue refining
that and making materials choices. Propulsion is working on component
selection. Fuselage is working on their part of the prototype aircraft as
well as placing the aft wing to allow for rotation. There is a lot of
design work being done this week, and we will move fast. After this week,
we will have a pretty complete picture of the final design, and can start wing
prototyping.
10/25/07:
In yesterday's general meeting our team name was decided. For the 2007/2008 contest year we will be building the AirBuffs A420 due to the the "Passengers and Cargo" payload requirement. To come up with the A# it was decided to use the contest date, as that would be the date that we will make our attempt at grabbing the first place prize.
10/21/07:
Update: Last week we were fairly quiet as the seniors have
been attending PDR presentations. This gave everyone a short breather
until we make the final push to the end of the semester. One thing of
note is that the aero team discovered that the PDR design was too stable, and
would not be able to pitch correctly. This has led to a redesign of the
aero, structures, and propulsion subsystems which is ongoing. Stefan,
Josh, and I made a 1/4 scale version of the current design and glide tested it
with excellent results. See the videos here: http://dbf.colorado.edu/lock
Plans:
For the upcoming week, there is a lot to do. The
seniors do the PDR presentation Oct. 22 at 4 PM in ECCR 245. Anyone who
wishes to come is welcome.
Also, all teams will be doing design work in order to get
enough information to build a prototype. All teams will be working first
on span optimization in order to determine what the best span of the aircraft
should be. With that, the chords and sweep angles can be sized for each
wing. Also, the structures team will begin working on more polished
structural models of the aircraft. Missions and fuselage will work on
fuselage design and sizing as well as payload restraint prototyping.
Propulsion will be working on redesigning their systems and integration into
the aircraft. Avionics will continue working on choosing a system and
beginning to work on testing procedures.
By the end of the week, the goal is to have the geometry of
the wings and tail done and have a good idea on the airfoils and
incidences. Also, testing protocols will be written for each subsystem so
that tests can be documented.
There is a lot of work to do, and so I encourage everyone to attend subsystem meetings since there will be a lot of work done in those this week.
Update: Last week was a flurry of activity as the seniors
prepare for the Preliminary Design Review. This review is to demonstrate
the feasibility of the project, and present the initial design, and defending
why we chose that design. The presentation is up to 90 slides right now
(including appendices) and represents the work we have done over the last 4 or
5 weeks. Obviously, that is a lot of work.
I want to commend everyone for all their work and help that they gave through
this entire process, the seniors really do appreciate your input. So not
much to report, except that the PDR is 98% done, and will be turned in tomorrow
by
Plans for the week: This week is going to be quieter than previous weeks,
because the seniors will be attending PDR presentations for other teams.
This removes most of the meeting time for the week. We will still have
the Wednesday general meeting at
Aerodynamics will be working on sizing and airfoil selection to prepare to
build the first prototype.
Avionics will be nailing down telemetry specs and deciding on a telemetry
system to purchase or acquire.
Missions & Fuselage will be working on an initial shape and size of the
fuselage for the first prototype.
Propulsion will be working to get motors and props selected for static testing,
and helping decide on a power system for the prototype aircraft.
Structures will be refining their analysis and beginning FEM work in order to
decide on materials for both the prototype and final aircrafts.
The big push right now is to build a prototype and test it by
Thanksgiving. This is only 5 weeks away, not much time. Flying this
early will reveal a lot of information about the aircraft and greatly aid the
design process by incorporating real-world data into the design.