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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