P 16121 SAE Aero Aircraft Design Build Detailed

P 16121: SAE Aero Aircraft Design & Build Detailed Design Review

Agenda Project Review ◦ Project Status ◦ Timekeeping ◦ Looking ahead to MSD II Timeline Test Plans Revisions ◦ ◦ ◦ Payload Support Structure Sizing Design Details ◦ Bolting 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 Final Analysis Conclusions Bill of Materials ◦ Part Numbering ◦ Bill of Materials Updated Risks

Project Review Where we are and where we are going

Status Summary 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

Timekeeping 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

MSD II Preliminary Plan 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 5/95/135/175/21 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 Tentative MSD II Plan Several early key items are prime opportunities to get ahead of the schedule and lessen the phase 2 and 3 time crunch

Test Plans This document contains the plan for the build phase and design. The document will be updated to keeping scheduling on time.

Complete Aircraft The full system

Revisions Beneficial iterations

Fuselage Revisions The Fuselage has been revised to accommodate the payload support structure and to be more easily monokote covered

Balsa Sheathing provides a more uniform surface for the monokote to cling to

Front Bulkhead airflow Electronics 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 Top Panel is transparent to show detail of how payload support structure fits inside. Magnet connections on four corners.

Revision two of Secondary Landing Gear Material: Aluminum 6061 -T 6 0. 0975 0. 33 831. 12 Reduce weight by removing more material.

Main Landing Gear Reinforcement Reduce problematic stress by increasing the bearing surface area

Spar Bending Moment Distribution Estimation 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.

Material: Aluminum 6061 -T 6 0. 0975 0. 33 3586. 9 Factor of Safety 11. 15 A 0003 Spar Weight Reduction of weight in the longer aft spar. Similar efforts made in the shorter forward spar. Conditions good despite worse-than-reality loading.

Wingbox Load Structure An aluminum inner truss supports the wings and tail

Tail Mounting The tail is bolted into the rear

Spar Mounting Captive nuts to secure wing spars to wingbox

Spar Mounting The wing spars meet in the center and each have 2 bolts

Spar Mounting Load is transferred from the spars to the fuselage supports

Remaining Subsystems Last of the first revision design work

Tail Boom Loading

Tail Boom Stress Analysis

Tail Structure Tail meets aerodynamic requirements

Tail Structure The horizontal stabilizer has the required taper

Tail Structure Vertical stabilizer is rectangular

Tail Structure Tail is secured by a sleeve around the tail boom and a bolt to keep it in place

Lateral Stability Requirements 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 mounts Servos have been moved into the tail on advise from the aero club

Rudder The rudder rotates around a pivot The control horn is at the base

Elevator The elevator is in one piece and has a control horn near the center

Ventral Fin/Bumper The 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 Rod In order to avoid having soft balsa wood resting on threaded surfaces we will be using many custom fasteners such as this.

Payload Support Structure Payload 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.

Final Analysis Conclusions Looking at how and why the analysis went the way it did

Performance Revisited Aerodynamics Computational Method Comparison XFLR 5 vs. FLUENT Vortex Lattice Method vs. Navier-Stokes + Spalart-Allmaras Simulate aerodynamic performance of horizontal stabilizer using FLUENT to verify results from XFLR 5

FLUENT Flow Field Mesh: FLUENT Flow Field Boundary Conditions:

FLUENT vs. XFLR 5 Results Comparison

FLUENT vs. XFLR 5 Data Tabulation

FLUENT vs. XFLR 5 Conclusions Lift Prediction is virtually identical: - XFLR 5 consistently predicts higher lift - FLUENT predicts later stall angle - Max lift is virtually identical Discrepancy with Drag: - XFLR 5 consistently predicts lower drag - XFLR 5 erroneously calculates viscous drag FLUENT predicts higher max efficiency angle 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

Bill of Materials What we have and what we need

Part Numbers 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

Totals

Fuselage

Wingbox

Wings

Tail

Payload • Payload material itself has not yet been determined • Cost estimate of $20. 00 listed currently

Landing Gear

Electronics

Fasteners • 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

Risk Tracking Keeping our priorities well ordered

Risk Assessment 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

Risk Chart