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Detailed Design Review
Project Review◦ Project Status
◦ Timekeeping
◦ Looking ahead to MSD II
Timeline
Test Plans
Revisions◦ Fuselage
◦ Landing Gear
◦ Reduced wing spar weight
◦ Wingbox Revisions and interface with other components
Final Subsystems◦ Tail and Tail Control Surfaces
Sizing
Design Details
◦ Wing Control Surfaces
Sizing
Design Details
◦ Payload Support Structure
Sizing
Design Details
◦ Bolting
Final Analysis Conclusions
Bill of Materials◦ Part Numbering
◦ Bill of Materials
Updated Risks
Where we are and where we are going
Design is “done” – revision need is expected
Drawing package is not complete. Most parts will be produced by non-official drawing by laser cutter.
Analysis suggests room to optimize substantially should there be time to do so
Gate Review is tentatively Wednesday of next week
Work plan is address problems that come up at this review
Looking ahead to MSD II: Opportunity to get ahead on our schedule on the next slide
Tentative MSD II PlanSeveral early key items are prime opportunities to get ahead of the
schedule and lessen the phase 2 and 3 time crunch
1/261/302/3 2/72/112/152/192/232/273/2 3/63/103/143/183/223/263/304/3 4/74/114/154/194/234/275/1 5/5 5/95/13
Final Paper to 75%
Final Paper Revision
Generate Production Prints (Autodesk .DWG)
Buy Material
Revise and Finalize waterjet and machining prints
Thrust Test Fixture Repair
Subsystem Level Preparation
Trust Test
Electronic System Test
Lasercut Parts
Machine Parts
Assembly of Fuselage
Assembly of Wingbox
Assembly of Wings
Subsystem Build and Test
Assembly of Tail
Assembly of Electronics into airframe
Final Monokote
Systems and Subsystem Level Build and Test
Aircraft Assembly
Aircraft Repair
Spring Break
Poster First Draft
Execution of Remain Testplan Items
Systems Level Test
Poster Final Draft + Print
Imagine RIT
Verification and Validation
MSD II Preliminary Plan
Test PlansThis document contains the plan for
the build phase and design. The document will be updated to keeping
scheduling on time.
The full system
Complete Aircraft
Beneficial iterations
Fuselage RevisionsThe Fuselage has been revised to
accommodate the payload support structure and to be more easily
monokote covered
Balsa SheathingBalsa Sheathing provides a more
uniform surface for the monokote to cling to
Front Bulkhead airflowElectronics get warm and wood glue is
flammable. We would like to have some airflow into and out of the electronics
bay to provide some thermal regulation
Magnetic Payload Bay TopTop Panel is transparent to show detail
of how payload support structure fits inside. Magnet connections on four
corners.
Revision two of Secondary Landing GearReduce weight by removing more
material.
Material: Aluminum 6061-T6
𝜌 [𝑙𝑏/𝑖𝑛3] 0.0975
𝐸 [𝑝𝑠𝑖] 1 × 107
𝜈 [−] 0.33
𝜎𝑦 [𝑝𝑠𝑖] 4 × 104
𝜎𝑉𝑀𝑚𝑎𝑥[𝑝𝑠𝑖] 831.12
Factor of Safety 48.127
Main Landing Gear ReinforcementReduce problematic stress by
increasing the bearing surface area
Spar Bending Moment DistributionEstimation of the bending forces applied on the
wing spars. Analysis assumes a constant, not tapering, moment distribution and applies the full
load to each individual spar.
Comsol stress analysis of unrevised forward spar
Spar is substantially stronger than is necessary for this loading
Comsol stress analysis of unrevised aft spar
Like the forward spar this member is substantially stronger and heavier
than it needs to be.
A0003 Spar Weight ReductionReduction of weight in the longer aft
spar. Similar efforts made in the shorter forward spar. Conditions good despite
worse-than-reality loading.
Material: Aluminum 6061-T6
𝜌 [𝑙𝑏/𝑖𝑛3] 0.0975
𝐸 [𝑝𝑠𝑖] 1 × 107
𝜈 [−] 0.33
𝜎𝑦 [𝑝𝑠𝑖] 4 × 104
𝜎𝑉𝑀𝑚𝑎𝑥[𝑝𝑠𝑖] 3586.9
Factor of Safety 11.15
Wingbox Load StructureAn aluminum inner truss supports the
wings and tail
Tail MountingThe tail is bolted into the rear
Spar MountingCaptive nuts to secure wing spars to
wingbox
Spar MountingThe wing spars meet in the center
and each have 2 bolts
Spar MountingLoad is transferred from the spars to
the fuselage supports
Last of the first revision design work
Tail Boom Loading
Tail Boom Stress Analysis
Tail StructureTail meets aerodynamic requirements
Tail StructureThe horizontal stabilizer has the
required taper
Tail StructureVertical stabilizer is rectangular
Tail StructureTail is secured by a sleeve around the
tail boom and a bolt to keep it in place
Lateral Stability RequirementsRequirements of Lateral Stability
Longitudinal, Directional and Lateral Control
Contributions to the controllability of the aircraft
Elevator Sizing Requirement
Criteria for the selection of the sizing of the elevator
Aircraft Stability and Control
Servo mountsServos have been moved into the tail
on advise from the aero club
RudderThe rudder rotates around a pivot
The control horn is at the base
ElevatorThe elevator is in one piece and has a
control horn near the center
Ventral Fin/BumperThe ventral fin slots into the base of
the tail. It’s primary purpose is to protect the tail from ground strikes.
Servo Motor Mounting Area Location for the motors accounted
mostly for feasibility. Also, provided the desired feature of a removable
hatch.
Overall View
Representative End Threaded RodIn order to avoid having soft balsa wood resting on threaded surfaces we will be
using many custom fasteners such as this.
Payload Support StructurePayload support structure allows the payload to be firmly centered within the bay. Also, if we need to
adjust our payload location within the bay it should be trivial to alter the shape of the wooden
supports.
Looking at how and why the analysis went the way it did
Performance Revisited
Aerodynamics Computational Method Comparison
XFLR5 vs. FLUENT
Vortex Lattice Method vs. Navier-Stokes + Spalart-Allmaras
Simulate aerodynamic performance of horizontal stabilizer using FLUENT to
verify results from XFLR5
FLUENT Flow Field Mesh:
FLUENT Flow Field Boundary Conditions:
FLUENT vs. XFLR5 Results Comparison
FLUENT vs. XFLR5 Data Tabulation
CL CD CL/CD CL CD CL/CD
0 0.011978 0.020634 0.580498 0.000000 0.011000 0.000000 NA 60.909148 NA
1 0.073237 0.021078 3.474571 0.065000 0.011000 5.909091 11.917215 62.834341 51.888493
2 0.134190 0.022225 6.037795 0.130000 0.012000 10.833333 3.171960 59.751644 56.849049
3 0.195450 0.024098 8.110632 0.195000 0.014000 13.928571 0.230503 53.010657 52.796282
4 0.256890 0.026707 9.618827 0.260000 0.016000 16.250000 1.203351 50.141663 51.267679
5 0.318020 0.029968 10.611986 0.324000 0.019000 17.052632 1.862870 44.796602 46.562331
6 0.379040 0.033913 11.176835 0.388000 0.023000 16.869565 2.336254 38.349762 40.595088
7 0.439680 0.038571 11.399238 0.452000 0.028000 16.142857 2.763323 31.758574 34.446322
8 0.499460 0.043841 11.392532 0.515000 0.033000 15.606061 3.063699 28.216707 31.212949
9 0.558400 0.049720 11.230893 0.577000 0.039000 14.794872 3.276378 24.165915 27.388081
10 0.616220 0.056217 10.961453 0.638000 0.046000 13.869565 3.473075 19.990804 23.423222
11 0.673130 0.063348 10.625908 0.698000 0.053000 13.169811 3.627665 17.788015 21.381187
12 0.729050 0.071043 10.262095 0.758000 0.061000 12.426230 3.893615 15.211711 19.077079
13 0.783480 0.079321 9.877334 0.816000 0.069000 11.826087 4.066322 13.917112 17.958027
14 0.836100 0.088007 9.500381 0.874000 0.078000 11.205128 4.432489 12.056118 16.466609
15 0.886300 0.097164 9.121691 0.930000 0.087000 10.689655 4.811980 11.037988 15.828950
16 0.933440 0.106660 8.751547 0.985000 0.097000 10.154639 5.375201 9.486399 14.842678
17 0.974760 0.116530 8.364885 1.039000 0.112000 9.276786 6.380105 3.964469 10.338036
18 1.006900 0.126760 7.943358 NA NA NA NA NA NA
18.5 1.023600 0.132390 7.731702 NA NA NA NA NA NA
19 1.034400 0.137880 7.502176 NA NA NA NA NA NA
19.5 1.018200 0.146180 6.965385 NA NA NA NA NA NA
20 1.020900 0.152000 6.716447 NA NA NA NA NA NA
% difference
CL/CDAngle-of-Attack (deg)
% difference
CL
% difference
CD
FLUENT XFLR5
FLUENT vs. XFLR5 Conclusions
Lift Prediction is virtually identical:
- XFLR5 consistently predicts higher lift
- FLUENT predicts later stall angle
- Max lift is virtually identical
Discrepancy with Drag:
- XFLR5 consistently predicts lower drag
- XFLR5 erroneously calculates viscous drag
Longitudinal Static Stability is Virtually Identical
Design Impact:
- Expected lift performance should be achieved, but may be smaller
- Drag is underestimated, so thrust power required should be increased
- Expect longitudinal stability should be achieved
FLUENT predicts higher max efficiency angle
What we have and what we need
We devised a simple part numbering scheme to assist in keeping track of our parts and files as they multiply◦ Designations:
A#### – Assembly
N#### – Multi-use
P#### – Fasteners
F#### – Fuselage
W#### – Wing
E#### – Electrical
G#### – Landing Gear
T#### – Tail
B#### - Wingbox
L#### - Payload
• Payload material itself has not yet been determined
• Cost estimate of $20.00 listed currently
• We anticipate receiving most standard fasteners free of
charge from MSD, the machine shop or Fastenal
• Estimated expense would be reduced by over $50.00
Keeping our priorities well ordered
Document can be found on Edge
Budget still a major risk
Reduced likelihood of two risks◦ Limited aerospace engineering knowledge
◦ Limited knowledge of model aircraft manufacturing