p10232 system design review - rochester institute of ...edge.rit.edu/content/p10232/public/concept...

James Reepmeyer – Lead EngineerBrian Smaszcz – Airframe Design LeadAlex Funiciello – Airfoil Design LeadMichael Hardbarger – Flight Control Systems

P10232 System Design Review October 7, 2009 of 20

ContentsP10232 Project Background........................................................................................................................3

Project Summary.....................................................................................................................................3

Customer Needs......................................................................................................................................3

P09232 Senior Design Project..................................................................................................................3

Engineering Specifications...........................................................................................................................4

Sub-system specs........................................................................................................................................4

Body Structure.........................................................................................................................................4

Airfoil/Wing.............................................................................................................................................4

Propulsion................................................................................................................................................5

Landing gear............................................................................................................................................5

Flight controls..........................................................................................................................................5

P10232 Concept Generation.......................................................................................................................6

Aircraft Style............................................................................................................................................6

Airframe (key features)............................................................................................................................6

Airfoil.......................................................................................................................................................7

Landing Gear............................................................................................................................................7

Propulsion................................................................................................................................................8

Flight Control Actuation Systems.............................................................................................................8

P10232 Concept Selection...........................................................................................................................9

Aircraft Type............................................................................................................................................9

Airframe Design.......................................................................................................................................9

Tail Selection..........................................................................................................................................10

Airfoil Selection......................................................................................................................................10

Landing Gear Selection..........................................................................................................................11

Propulsion Selection..............................................................................................................................12

Flight Control Actuation System............................................................................................................12

P10232 Selected System Design............................................................................................................13

Selected Concept...............................................................................................................................13

System Architecture (Physical)..............................................................................................................13

System Architecture (Electrical).............................................................................................................14

Risk Management......................................................................................................................................15

Important Links.........................................................................................................................................17

Bibliography...............................................................................................................................................17


P10232 Project Background

Project Summary

The goal of the UAV Airframe C project is to provide an unmanned aerial platform used for an aerial imaging system. The airframe must support the weight and interfaces for the designed imaging system. The aircraft must be operated remotely and be a viable alternative to current aerial imaging methods. This is a second generation airframe, expanding on the previously laid ground work established by the P09232 UAV B Senior Design Project.

Customer Needs

Airframe must be able to carry a fifteen pound payload Easy integration with measurement controls box and different aerial imaging systems Ability to remotely control aircraft and activate payload Ability for flight communication between aircraft and ground relay Aircraft provides twenty minutes of flight time for local area photography Aircraft has the potential to take off and land on site Easy assembly and disassembly of the aircraft for transportation

P09232 Senior Design Project

The Unmanned Aerial Vehicle concept began with last year’s Senior Design team. The design used was a traditional monoplane powered by a two-stroke gasoline engine, with a small cambered flat bottom airfoil. Shortly after take-off on the plane’s first flight the pilot lost control of the aircraft during a banked turn. The plane proceeded to knife edge toward the ground, where the wings sheared off shortly before impact. The failure was determined to be from the bending stress applied to the wings during the banked turned. After analysis, it was concluded that the main fiberglass spar used to support the wing was not properly selected to handle the loads experienced in flight. Additionally, the deflection in the wing during flight reduced the effectiveness of the flight control surfaces thereby greatly reducing the pilot’s control of the aircraft.

https://edge.rit.edu/content/P09232/public/Home


Engineering SpecificationsThe following are the design specification for the Airframe C design.

1. The aircraft shall have a maximum weight of 30 lbs without payload2. The aircraft shall have a minimum flight ceiling of 1000 ft3. The aircraft shall be able to sustain a flight of at least 50mph in calm conditions4. The aircraft shall be capable of stable flight with a 15 lb payload5. The aircraft shall utilize an open architecture payload interface6. The aircraft shall provide a mechanical interface to the payload7. The aircraft will provide a stable platform for the photographic instrument payload8. The aircraft shall sustain steady flight in a controllable manner for at least 20 minutes9. The aircraft shall be able to re-launch as soon as it has been re-fueled or re-charged10. The aircraft shall be able to operate for at least 25 regular flights without needing routine

maintenance11. The aircraft shall be able to take off under its own power from a 1000 ft runway12. The aircraft shall be able to be transported in a motor vehicle when disassembled13. The aircraft will be easy to assemble and disassemble by one person14. The aircraft shall be able to navigate while on the ground15. The aircraft should have similar flight characteristics to a trainer RC plane16. Final cost must be less than the cost of renting a Cessna for a day (~$8000)

Sub-system specs

Body Structure The structure shall support 15lbs of payload. The structure shall have an accessible payload bay to contain the camera system. The structure shall connect to the other components in a manor such that a single competent

person may assemble/disassemble the plane for transport. The structure shall resist deformation under normal operation. The structure shall house the planes power system, and provide a mount for the engine. The structure shall be durable, enabling multiple flights without servicing.

Airfoil/Wing The airfoil shall provide enough lift to carry the craft weight (up to 30lbs) plus the payload

weight (15lbs). The airfoil shall minimize drag to enable the plane to fly for a minimum of 20 min. The wing shall be able to be disassembled to a size such that they will be transportable by motor

vehicle. The wing shall be structurally rigid and free of in flight flutter. The wing shall contain control surfaces capable of maneuvering the plane in a manner similar to

a trainer style aircraft.


The wing planform area shall be designed such that wing loading is kept under 20 oz./ft2. The wing shall be structurally sound, allowing for repeatable 20 min. flights without

maintenance. The wing shall resist deformation under loading allowing the pilot to remain in control of the

aircraft at all times.

Propulsion The propulsion system shall provide uninterrupted, constant power for at least 20 min. The propulsion system shall provide enough thrust to overcome drag and accelerate to flight

speed in the length of a 1000ft runway. The propulsion system shall be clean and easy to maintain. The propulsion system shall be reusable, only requiring refueling/recharging.

Landing gear The landing gear shall allow the plane to be controllable on the ground (taxi and takeoff). The landing gear shall protect the airframe, prop and payload during takeoff, landing, and

taxiing. The landing gear shall provide minimal resistance on a grass runway, allowing the plane to reach

flight speed in less than 1000 ft.

Flight controls The flight control system shall be able to actuate control surfaces, allowing the aircraft to be

flown like a basic trainer aircraft. The control system shall maintain reliable control for at least 20 min. The control system shall interface with the payload, triggering a camera system to take a

picture.


P10232 Concept Generation

Aircraft Style Monoplane – Traditional single winged aircraft design Biplane – Two stacked wings; same lift half the wingspan More than 2 wings - Same idea as a biplane, but 3 or more wings Delta Wing – Plane With a delta shaped wing design Flying wing – A plane consisting only of a wing structure; ie. No fuselage Dirigible – A lighter than air aircraft such as a blimp or hot air balloon Rocket – A rocket propelled craft Helicopter – VTOL style craft with horizontal blades and no fixed airfoils. Can have one or more

main rotors

Due to the variety of these options it was necessary to narrow down the overall direction of our research prior to generating sub-concepts. After some initial research it was clear we would be working with a fixed-wing aircraft (thus disqualifying the dirigible, rocket, and helicopter options). For more on the selection process please see the Concept Selection section.

Airframe (key features) Canards Motor / Engine placement

o Pusher – motor in back of the plane, pushes plane through the airo Puller – motor on the front of the aircrafto Multiple Power Sources

Wing Mounted – motors attached to wings instead of built into the fuselage Twin Fuselage – one motor on the front of each fuselage Push and Pull – one motor on the front, one motor pushing from the back

Winglets – Small vertical stabilizers on the wing tips Dual Fuselage – 2 fuselages running parallel, could hold cargo between them Twin Boom – 2 extended booms connect the wing / fore-plane to the tail Cambered (lifting) Tail V-Tail – Two ‘slanted’ tails; fighter-jet style H-Tail – Two vertical stabilizers / rudders on either end of the tail’s horizontal stabilizer T-Tail – A traditional tail design but with the horizontal surface at the top of the vertical

stabilizer Cruciform tail – Same as a T-tail but with the horizontal surface half-way up the vertical stabilizer Tandem Wings – one bottom mount front wing and one top mount back wing Swept Wings – Wings swept back fighter-jet style (supersonic wing design) Folding Wings – Wings that fold for transportation / storage


Airfoil Thin wing – Airfoil with a low thickness to chord ratio. Thick wing – Thickness to chord ratio of 12% or higher. Symmetrical Wing – Symmetric about chord line Cambered Wing – Curved airfoil to increase the nozzle and diffuser effects produced by the

wing. Flat Bottomed Wing – A type of cambered airfoil with a flat, or nearly flat bottom surface. Elliptical Wing – Theoretically ideal wing design with an elliptical planform shape. Rectangular Wing – Rectangular planform area. Tapered Wing – Wing with a longer chord at the root than at the tip. Trapezoidal planform

shape. Additional Lifting Surfaces (i.e. Canards) – Adds lift, allowing for a smaller main wing. Wing Mounting (top / center / bottom)

o Top – Wing is above the fuselage, above the centre of gravity.o Middle – Wing mounted to side of fuselage.o Bottom – Wing sits under the fuselage, below the planes centre of gravity.

Swept Wings – Wing tips are behind the wing’s root, swept back, decreasing the speed of the air across the wing.

Dihedral – Wing with a slight upward angle, with the tip higher than the wing root. Anhedral – Wing with a downward angle, with the tip lower than the wing root.

Landing Gear Number of Wheels

o 2 wheelso 3 wheelso More wheels

Non-Wheeled Landing Gearo Skis – intended for use on snowo Pontoons – for use on lakes (which are found near all nuclear power plants)o Skids – skid plates on the underside of the plane in place of landing gear

Retractable Landing Gear Wheel Placement

o Wing Mounted – anchored to the wings instead of the fuselageo Tricycle layout – font wheel turns, 2 wheels in the backo ‘Conventional’ layout – aka tail dragger, rear wheel turns, 2 wheels in front

Launch Assisto Car-top – released from the top of a moving vehicle (requires highway)o Catapult – instant launch from some sort of a stand. Crossbow design?

Brakes – reduced stopping distance ‘Leave-behind’ landing gear – plane would liftoff from a sled with wheels, leaving the sled

behind


Propulsion Power Source

o Electric Motor DC Brushless DC Brushed AC

o Fuel Powered 2-Stroke (chainsaw / weed whacker) Glow / Nitro fuel Wankel 4 –Stroke Diesel

o Rocket Rocket as main propulsion Rocket assisted launch

Exposed propeller Ducted Fan Multiple-Bladed propeller (>2 blades)

Flight Control Actuation Systems Servo Motor Stepper Motor Pneumatic Hydraulic EHA (Electro Hydrostatic Actuator)


P10232 Concept Selection

Aircraft Type

PlaneDirigibl

eHelicopte

r RocketDesign 0 + - - +Cost (initial) 0 - 0 +Cost (sustainable) 0 - - 0 - -Controllability 0 - - - - *Transport 0 - - + +Flight Time 0 ++ - *Payload 0 - - - -Airspeed 0 - - - ++Total 0 -7 -6 N/A

* Rocket fails to meet time and controllability specifications

As shown in the concept selection matrix, the fixed-wing airplane is considered the best option for a successful design given the chosen criteria.

Airframe DesignMonoplan

e Bi-plane DeltaFlying Wing

Tandem Wing Split Body

Boom Tail

Design 0 - - - - - - - - -Cost (initial) 0 - 0 + - - - - +Piloting Difficulty 0 - - - - - - + 0Transport 0 + - - - - +Flight Time 0 0 0 ++ + + 0Payload Flexibility 0 0 - - - ++ - -Payload Weight 0 0 0 + ++ + 0Airspeed 0 - + - 0 - 0Total 0 -3 -3 -4 -2 -3 -1

The monoplane aircraft design was the selected concept to carry into detailed design. The monoplane is the most commonly used airframe design in many applications, and to accommodate our short design and build lead time, this will allow for the highest chance of success.


Tail SelectionCambered H-Tail V-Tail T-Tail Crucifix Tail

Stability 0 + + - -Design Difficulty 0 - - - - - - -Weight 0 - + - -Controllability 0 + - + +Drag 0 + + 0 0Flight Envelope 0 0 0 + +Cost 0 - - - -Total 0 0 -1 -3 -3

We chose to use the Conventional tail configuration for UAV C. It will use a cambered horizontal stabilizer which will create reverse lift and help us to keep the plane stable in flight with varying payloads. This is the most commonly used tail configuration and also the most straight forward to design since no additional strengthened connection points are required.

- The twin tail or H-tail could work for our application but would increase the amount of design work and components increasing weight and reducing low speed handling.

- The T-tail would require an extremely robust tail piece in order to withstand the forces caused by the increased moment forces on the connection point of the fuselage due to being located at the top of the vertical stabilizer.

- The V-tail is cutting edge technology and would require a more advanced control system in order to experience the same control abilities of alternative configurations.

- The cruciform is used to keep the tail out of the engines' wake or to avoid complex interference drag. It requires a more robust tail design and for our small scale would not see any great performance gains.

Airfoil SelectionHigh Camber- Flat Bottom

High Camber - Under Cambered

Low Camber Reflex Symmetric

Lift 0 + -- -- --Drag 0 + + - -Stall Angle 0 + - - 0Stall Speed 0 + - - 0Moment 0 - + ++ +Structure 0 - 0 0 0Total 0 2 -2 -3 -2


After critiquing last year’s design, the concept selected for the Airframe C’s airfoil is an under-cambered thick airfoil design. The more aggressive cambered airfoil will produce more lift, decrease stall speed, and decrease the required chord and wingspan compared to the UAV B; allowing the aircraft to manage the same payload with a smaller wing span and planform. Final airfoil selection will be based on XFOIL analysis. The wing will likely be rectangular in shape due to its ease of design and implementation. The planform area will be selected based on wing loading.

Landing Gear Selection

Conventional Tricycle Skid Plates Pontoon/Floats SkisFlight Drag 0 + + - - 0Ground Control 0 0 - - - 0Nose Over 0 ++ - 0 0Ground Loop 0 + - 0 0Cost 0 - + + -Load Handling 0 - + + 0Risk of Prop Damage 0 - - - 0Cargo Protection 0 - - - 0 0Operational Environment Restrictions 0 0 - - - - -Total 0 0 -5 -4 -3

As shown by concept selection matrix, either the conventional landing gear system or a tricycle style landing gear system would be appropriate for our system design. After careful consideration, the conventional style landing gear system was chosen as the concept to move forward with because it naturally lends itself to a better angle of attack on the ground, creates less drag, and better protects vital aircraft components in case of failure.


Propulsion Selection

Glow/Nitro Gasoline ElectricInitial Cost * 0 0Running Cost 0 0 +Controllability 0 0 +Power * 0 - -Weight 0 0 - -Design Flexibility 0 0 ++Fuel/Battery Consumption 0 0 020 min Flight Time * 0 0Vibration 0 0 +Reliability - 0 ++Maintenance 0 0 ++Total N/A 0 5

*Glow engines of the size needed are not readily available

Gasoline Motor Research

Name Volume PowerEngine Weight

Total Weight

with Fuel

Engine Price

Price to Power Ratio

Price to Weight Ratio

Power to

Weight Ratio

CC W kg kg $ $/W $/kg W/kgXY 50cc 50 3502 1.62 2.26 238 0.07 105.38 1550Turnigy 50 50 4103 1.38 2.02 240 0.06 118.9 2033DLE 55 4103 1.35 1.99 319 0.08 160.42 2063RCG 50 3879 1.36 2 209 0.05 104.58 1941Fuji BT-64 64 4252 2.28 2.92 450 0.11 154.19 1457FUJI 86 86 5222 3.2 3.84 800 0.15 208.41 1360Fuji 43 43 3133 1.8 2.44 450 0.14 184.54 12853W-55iUS 55 4476 1.9 2.54 625 0.14 246.21 1763

NameRPM/

V Volts

Constant

CurrentConstant

Power Weight Cost

Number of Cells Needed

Required Number

of Battery Packs

Total Weight

of Battery Payload

Total Weight

Total Cost

Weight To Cost Ratio

Power/ Weight

rmp/v V A W kg $ # # kg kg $ $/kg W/kgRim Fire 65cc 160 55.5 135 7500 1.4742 270 15 9 6.71 8.19 810 98.94 1117.26Rim Fire 50cc 230 55.5 110 5000 1.2474 250 15 8 5.97 7.21 720 99.8 837.95Turnigy Aero Drive XP 63-74 170 37 90 3250 0.8391 60 10 6 4.48 5.31 540 101.61 726.22Turnigy Aero Drive XP 63-64 230 37 90 3150 0.6889 60 10 6 4.48 5.16 540 104.57 703.87Exceed RC 245 33.3 60 2700 0.6464 50 9 4 2.86 3.51 330 94.12 944.06HXT 63-74 200 37 50 2400 0.7002 60 10 4 2.86 3.56 340 95.5 839.17Rim Fire 1.6 250 44.4 45 1665 0.635 140 12 3 2.14 2.78 210 75.54 776.23

Electric Motor Research

Number of Cell Packs Needed=1000×[Current Draw (A)× FlightTime (hours )BatteryCapacity (mAh) ]


Our research into the differences between the gasoline engines vs. the electric motors have not yet lead us to any conclusive results. More research and expert opinions will be sought before any decisions are finalized.

Flight Control Actuation System

Electric (servo)

Electric (stepper)

Pneumatic Hydraulic EHA

Difficulty of Design 0 - - - --Complexity 0 -- - - --Quick Connect compatible 0 0 -- -- 0Weight 0 - - -- 0Power output 0 0 + ++ ++maintenance 0 0 - - -cost (initial) 0 - 0 - --cost (sustained) 0 - 0 - -Total 0 -6 -5 -7 -6

After considering the commonly used alternatives we concluded an off-the-shelf electric servo system would work best. Furthermore we have a (hopefully) functional servo system from Airframe B. This hardware will need to be analyzed and tested prior to use to make sure it matches our needs. Successful utilization of this hardware will help reduce the overall cost of our build.


P10232 Selected System Design

Selected ConceptThe selected system design for the P10232 project will be an electrically powered monoplane

with a standard cambered tail section. The airfoil will be under-cambered to provide more lift and reduce the wingspan. The wing will be rectangular for its ease of design and will be top-mounted to the airframe. A conventional landing gear system will be used to assist in short take-off and for its low drag properties.

System Architecture (Physical)


System Architecture (Electrical)

Risk Management

ID Risk Item Effect Cause Likelihoo

d Severit

y Importanc

e Action to Minimize Risk Owner

1 Flight Test

Failure Team fails to meet project

deliverable

Poor aircraft design, pilot

error, etc. 3 3 9

Design aircraft and associated tests correctly. Study weather

for optimal test conditions Lead

Engineer

2

Meeting Project

Deadlines

Project will run behind schedule, or project

deliverables are not met

Poor planning and poor execution 3 2 6

Create proper schedules with an appropriate buffer time

between dependent actions Team Lead

3 Component

Redesign

Forced project redesign can force the project to run

over deadlines

Aircraft was not designed with

proper components 1 3 3

Smart aircraft design with proper backing analysis.

Compliance with subsystem interface designs.

Entire Team and

Lead Engineer

4 H1N1/Illness Team members can fall

behind in work Germs 3 1 3 Proper cleanliness and Hygiene Entire Team

5 Build Time Runs Over

Delay in meeting project deliverable, flight testing does not run on schedule

Poor scheduling and poor work

habits 2 2 4 Begin build phase early and

maintain positive team morale Team Lead

6 Component

Testing Failure Delay in project deliverable

or testing schedule

Faulty component or poor system

design 1 2 2 Test parts early and properly

design all critical systems Entire Team

7 Miscellaneous Damages/Theft Loss of progress and time Negligence 1 3 3

Ensure all parts are properly stored and secured

Entire Team

ID Risk Item Effect Cause Likelihood

Severity

Importance Action to Minimize Risk Owner

8

Budget Increase Needed

Unable to purchase critical parts needed for aircraft design and build

Expensive design or over design 1 2 2

Have budget clearly defined and avoid expensive components where possible .

Team Lead and Lead Engineer

9

Budget Driven Redesign

Team will have to redesign aircraft systems, increasing time needed for completion

Improper knowledge of budget constraints or funding restricted 1 3 3

Have budget clearly defined and avoid expensive components where possible .


10 Part Lead Time

Parts required for assembly delay build progress

Parts were not ordered far enough in advance 2 1 2

Order parts at the end of MSDI and make sure all parts are ordered


11

Team Member Injury

Team member can fall behind in work resulting in a progress delay Multiple 1 2 2

Every team member acts in a responsible manner ensure work is done in a timely manner

Entire Team

12Critical Data Loss

Component re-design or analysis will need to be repeated

Hard drive failure or lost flash drive 1 2 2

All documents are backed up on EDGE

Entire Team

13 Winter Break Start Up

Ramp up time for project build is longer due to winter break

The break between Fall and Spring quarters 1 2 2

Continue work and project updates during the winter quarter

Entire Team

Important Links

P10232 Project Website - https://edge.rit.edu/content/P10232/public/Home

P09232 Project Website - https://edge.rit.edu/content/P09232/public/Home

BibliographyReyes, Carlos. Model Airplane Design Made Easy. Albuquerque: RCadvisor, 2009.

Ulrich, Karl T.; Eppinger, Steven D. Product Design and Development (4th ed.). New York, NY: McGraw-Hill, 2008.



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