Master_Presentation9a

advertisement
Senior Design Project
Cirrus Design
AEM 4331
Jon Anderson
Mike Asp
Kyle Bergen
Ejvin Berry
Cody Candler
Jim Forsberg
Mike Gavanda
Alex Messer
Dan Poniatowski
www.cirrusdesign.com
Agenda
•
Introduction
– Problem Overview
– Requirements and goals
– Program Plan
•
•
•
Wing Trade Study Overview and Results
Cargo Pod Design Overview and Results
FMEA and Conclusion
Problem Overview
• Wing Trade Study
– Improve wing performance and design high lift
devices that maintain current stall
performance.
• Cargo Pod Design
– Design a cargo pod for the SR-22 that is able
to carry two golf bags or two pairs of skis.
Wing Trade Study
• Requirements
– New wing design shall increase lift by 300
pounds at all flight conditions.
– High lift devices shall allow for the same stall
speed as the current wing.
• Goals
– No increase in drag
– No increase in wing area
– No increase in wingspan
Cargo Pod Design
• Requirements
– Pod shall not interfere with the safe operation of the SR-22.
– Pod shall be designed for optimum user utility.
– Pod shall not move the aircraft out of its intended center of
gravity limits.
– Pod shall be at least 8 inches from the exhaust.
• Goals
– Less than 15% drag increase
– Pod is capable of holding two golf bags or two pairs of skis.
– Pod is stylish and has good aesthetics
Program Plan
Program Plan Continued
Program Plan Continued
Wing Trade Study
Requirements:
•Lift 300 more pounds of payload
•Fly at same cruise speed and stall speeds
Results:
We were able to provide several solutions based on
hand calculations.
Our original approach using CFD failed.
Belly Pod design
Requirements:
• 2 sets of skis with equipment
• 2 sets of golf clubs (with drivers)
• Fishing poles
Results:
• Have a design that meets these goals
Alex Messer
FlowWorks Validation
90 hrs
Simulation in FlowWorks
Goal:
Reproduce data found from wind tunnel test in FlowWorks
Method:
• Build the same bodies that were tested in the wind tunnel in SolidWorks
• Simulate various ways of building the same object
• Simulate the same angles of attack and airspeeds used in the wind tunnel
• Test different mesh resolutions
• Compare resulting forces
Models
Open Return Tunnel:
Closed Return Tunnel:
Pressure differences between models
Drag vs. a
Lift vs. a
8Lift
3.0
6
2.5
Drag
2.0
4
1.5
2
a
1.0
0
-20
-10
0
10
20
0.5
-2
0.0
-20
-4
Lab Data
Model 1
Model 2
-10
Lab Data
0
Model 1
10
Model 2
20
a
Varying Reynolds Number
Re = 3.0x105
Drag vs. a
Lift vs. a
6
2.0
5
1.8
4
1.6
3
1.4
2
1.2
1
1.0
0
-20
-10
0
10
0.8
20 a
-1
0.6
-2
0.4
-3
0.2
-4
0.0
Lab Data
-20
FlowWorks
Drag
-10
a
0
Lab Data
10
FlowWorks
20
Varying Reynolds Number
Re = 3.4x105
Drag vs. a
Lift vs. a
Lift
8
Drag
2.0
1.8
6
1.6
1.4
4
1.2
2
1.0
0
-20
-10
0
10
20
0.8
a
0.6
-2
0.4
0.2
-4
a
0.0
-20
-10
0
10
-6
Lab Data
FlowWorks
Lab Data
FlowWorks
20
Varying Reynolds Number
Re = 4.0x105
Drag vs. a
Lift vs. a
Lift
12
Drag
3.0
10
2.5
8
6
2.0
4
1.5
2
a
0
-20
-10
0
10
1.0
20
-2
0.5
-4
-6
a
0.0
-20
-10
0
10
-8
Lab Data
FlowWorks
Lab Data
FlowWorks
20
Varying Mesh Resolution
Lift vs. a
Drag vs. a
Lift
6
2.0
5
1.8
4
1.6
3
1.4
2
1.2
1
1.0
0
-20
-10
0
10
0.8
20 a
-1
0.6
-2
0.4
-3
0.2
-4
0.0
-20
Lab Data
Resolution = 3
Drag
-10
a
0
Lab Data
10
Resolution = 3
20
Varying Mesh Resolution
Lift vs. a
Drag vs. a
Lift
6
2.0
5
1.8
4
1.6
3
1.4
2
1.2
1
1.0
0
-20
-10
0
10
0.8
20 a
-1
0.6
-2
0.4
-3
0.2
-4
0.0
-20
Lab Data
Resolution = 5
Drag
-10
a
0
Lab Data
10
Resolution = 5
20
Varying Mesh Resolution
Lift vs. a
Drag vs. a
Lift
6
2.0
5
1.8
4
1.6
3
1.4
2
1.2
1
1.0
0
-20
-10
0
10
0.8
20 a
-1
0.6
-2
0.4
-3
0.2
-4
0.0
-20
Lab Data
Resolution = 8
Drag
-10
a
0
Lab Data
10
Resolution = 8
20
Conclusions
What can we learn?
• FlowWorks does not give realistic lift results
• Drag results are reasonable
What can be done?
• Numerical approximation
• Xfoil
• Wind tunnel tests
Conclusions
CLmax
 S flapped 
 cos  H . L.
 0.9Cl max 
 S

ref


Raymer, Daniel P. Aircraft Design: A Conceptual Approach, 4th ed., AIAA education series, Blacksburg VA, 2006
Baseline Wing
Derived requirements
Current Cl in landing configuration at sea level at 60 knots is 1.98
We want to carry 300 extra pounds, so we need a Cl of 2.16
Must increase Cl by .18.
From Raymer, we can calculate the increase in Cl due to the current
high lift system being used on the SR-22.
Derived requirements
From the current wing design at 60 knots, we have
From Raymer, using a fowler flap
Therefore,
So we need to design a high lift system that will increase Cl by .83
Fowler flap
Jonathan Anderson
Hours: 100
•Designed a fowler flap system which produces the required
Fowler flap
Ways to increase Cl
•Extend the offset hinge distance
•Increase the flap deflection angle
•Change the flap shape
•Change the flap cove shape
•Use a track system instead of an offset hinge
Experiments have shown that increasing the flap deflection angle to
40 degrees will produce the greatest
in many different airfoils,
(with a chord of .3c to .4c.)
Planes using flaps with 40 degrees deflection
Cessna 150, 172, 206,
DHC Beaver, Otter
Piper Seneca, Cherokee
The shape of the flap cove and the flap itself will also play a role in
determining the maximum flap deflection angle and
. Much of
my time was spent looking for the right shapes in Floworks.
Fowler flap
If we increase offset distance to 16 inches, and flap deflection angle to 36
degrees, we get a c’/c = 1.178.
In increasing the flap deflection angle to 36 degrees,
increase above 1.3.
will also
It is possible to get at least 1.5 depending on the design. More investigation
of these ideas will be shown, but the actual number (1.5) is based on
technical reports using Reynolds numbers within 10%.
With these considerations, we can solve for
We find that
using
Fowler flap
This requires a flap that is 111.2 inches long
• 5.2 inches longer than the current flap
•Would impede on aileron
Need to move aileron down by about 5.2 inches. This is possible
because there is 18 inches of room for the aileron to move.
Notes:
• if the same flap span were to be used, the hinge offset distance below
the wing would have to be 19 inches for a deflection of 36 degrees.
•If the current flap—12 inch offset distance, 32 degrees deflection—were
to be extended, it would need to be 145 inches long, pushing the aileron
all the way to the tip and shrinking it 37% in length.
Fowler flap
Offset hinge length is 16 inches
Flap deflection angle is 36 degrees
Length of flap is 111.2 inches
Aileron is moved 5.2 inches toward tip
Some Fowler flap systems
referance
Slotted
non-slotted
non-slotted
Clean
1
2
3
Dirty
1.7
1.27
1.4
dCl
3.4
3.17
3.4
1.7
1.9
2
deflection
35
30
30
3
"Wind tunnel tests of the GA(W)-2 airfoil with 20 aileron, 25 slotted flap, 30
Fowler flap and 10 slot-lip spoiler ", Wentz, W. H., Jr., 1977, NASA,
ID#19790001850
4
"wind tunnel tests on model wing with fowler flap and specially developed
leading edge slot", Weick and Platt, Langley, 1933, ID#19930084816
5
"Lift and Drag tests of three airfoil models with fowler flaps", Abbott and
Turner, Langley, 1941, ID#19930092770
Figure on right is from reference 1,
Reynolds number of 2.2e6
Slotted flap design guidelines
• Optimum position of flap leading edge depends
primarily on the shape of the slot, and is best
determined by experiment
• In general, moves inward when lip is increased
but is generally about .01c forward of lip
• Usually a slot opening on the order of .01c or
slightly more is best.
• Best Cl’s are achieved using flaps with a wing
shape. Avoid flaps with a blunt leading edge.
from “Theory of wing sections”, Ira H. Abbott and Albert E. von Doenhoff, p.
212-213. Dover Publications, NY, 1959. (reference 4)
Slotted flap design
Two different shapes of slots with different flap shapes. The one on the left is a
smooth slot with max cl=2.535, the one on the right has a small lip with max cl=2.57.
For this experiment, Cl clean at the same (or near) angle of attack is about 1.3, and
Reynolds number was about 8e6.
Slotted flap design
Slot with a larger lip and with a maximum Cl=2.65.
from “Wind-tunnel investigation of an NACA 23012 airfoil with various arrangements of slotted flaps”, Wenzinger, Carl J; Harris ,
Thomas A, Langley Research Center, 1939, ID: 19930091739 (reference 5)
Conclusions
The design will produce the required extra lift to carry 300 more pounds
The aileron needs to be moved by about 5 inches
If aileron can’t be moved, then the offset hinge must be 19 inches long
•track system seems more practical in this case
Remark:
It is possible to get a higher
than 1.5, provided a detailed study of the flap
cove shape, flap shape, and location are optimized, therefore 1.5 seems like a
reasonable value, but experiments must be performed to confirm this.
Jim Forsberg
Hours worked: 107
• Designed a Plain Flap with leading edge slats system
that achieved the required
• Designed a Fowler Flap with leading edge slats system
that achieved the required
Plain Flap and Slat
Fowler and Slat
What will be considered to increase
• Extend chord length, by changing position of slat.
• Increase deflection angle (around
) on the Fowler
and Plain flap.
• Modify the shape of the Flap and Slat
Technical Reports
In these graphs
is around 1.4 for .16c
Schwier, W., “Lift increase by blowing out air, tests on airfoil of 12 percent
thickness, using various types of flap,” NACA Deutsche Luftfahrtforschung,
Forschungsbericht, 1947
Technical Reports (continued)
From looking at the table and other technical reports it is reasonable to
estimate that:
At a 16% chord increase
Quinn, John H. Jr., “Tests of the NACA 641A212 airfoil section with a slat, a double slotted flap, and boundary
layer control by suction,” NACA Langley Memorial Aeronautical Laboratory, Langley Field, VA, 1947
Plain Flap and Slats
Using this relationship:
With
and an increase in chord of 16%,
our
= 5728 in^2
This requires the Flap Span to be 118 in.; 12 in. longer than
the current flap span
Note: slat gets in the way of the transition cuff
Fowler and Slats
Based on Raymer, the optimal
for slats is 0.4.
• Looking at technical reports, and interpolating, the slats
need to produce around a 12% chord increase to get this
.
• Using the same relationship as before but now having
be 0.18.
This requires the slat span to be 92.6 in. long and the
Fowler Flap to remain at 106 in.
Drawback to having Slats
• Known to create some drag compared to a non-slotted
wing at cruise. Thus reducing the cruising speed.
• Heavier and more complex than other leading edge
devices (slots).
• Deicing gets more complicated
Conclusion
• Both the designs will produce the required 300 more
pounds.
• The Plain Flap and Slat system require to have 12 in.
more span than the current span.
Moving the Aileron toward the tip and getting in the
way of the cuff.
• The Fowler with Slat system requires no change in span
of the current wing and that the slat span does not
interfere with the transition cuff.
Conclusion
Going further:
• Experiment with the Fowler and Slat system, to get a
more accurate position for the Slat.
• Continued research in finding a more precise
for the Plain Flap and Slat system.
Michael Asp
Hours Worked 105
I was in charge of designing a
flapperon that would meet the design
requirement for CL.
Current Wing Configuration
Best Flapperon Configuration
Mechanical Configuration
Option 1
Option 2
*This would be investigated if we had more time to
determine which set-up is more effective
Comparison of Various Flapperon
Systems
Degrees of Flap Deflection
Type of Flap
20 deg
25 deg
30 deg
35 deg
40 deg
Plain Flaps
268.8 in.
(not
possible)
208.1 in.
182.9 in.
167.2 in.
208.1 in.
Fowler Flaps
163.7 in.
163.7 in.
161.5 in.
161.5 in.
159.4 in.
Slotted Plain
Flaps
166.4 in.
166.4 in.
166.4 in.
166.4 in.
166.4 in.
Table of Flap Spans Needed to Achieve Necessary Lift Coefficient
Conclusions
The best design will require:
– Removal of Flaps and Ailerons on current wing
– Implementation of an integrated (Flaps and Ailerons combined)
Flapperon that has a span of 159.4 in.
– Flapperon begins at the 36 in. Indentation from the root chord
already in place with current wing.
Drawbacks
• Adverse Yaw Effect at landing when flaps
are deployed and pilot tries to bank plane
– Can be overcome by pilot compensation
• Pilot does not deploy flaps part until lined up with
runway on final approach
Overall Wing Design Conclusion
The system which requires the least amount of complexity
and further investigation is the extended fowler flap.
This requires:
• 5 inches more flap span
• Longer offset hinge
• 4 degrees greater flap deflection
• Experimentation in flap shape and flap cove
Cargo Pod Design
Kyle Bergen
Ejvin Berry
Cody Candler
Mike Gavanda
Design Concept
• Ejvin Berry
• 96 hours
• Tasks
– Initial Aerodynamics Optimization
– Quick Prototype Modeling
– Final Concept Modeling
Cirrus SR22 Cargo Pod
Cargo Pod Guidelines
With 2 passengers (including pilot), 4 hours
of fuel, carry one of the following:
• 2 sets of skis with equipment
– Required volume of 12in x 6in x 77 in
• 2 sets of golf clubs (with drivers)
– Required volume of 35in x 11in x 50in
• Minimum 8” offset from firewall
– Exhaust Clearance
Pod on Fuselage
Clearance Envelope
Bottom View
Attachment View
Front Fairing (2)
Rear Fairing
Conclusions
• Demonstrates
– Practicality
• Meets required tasks, loads
– Ease of Operation
• Location specific, ease of entry
– Aesthetic Quality
– Aerodynamics
Recommendations
• Study feasibility of manufacturing
contoured pod surfaces to mesh with
fuselage.
– Increased capacity
– Fit CG envelope better
– Aerodynamics Improved
Attachment Methods
Individual Report by Kyle Bergen
80 hours worked
Attachment to Longerons
• Three points of attachment for stability and
ease of attachment
• Use longerons as hard points to anchor
mounting brackets which extend to belly.
• One piece assembly screwed to belly
attachment.
• Bolts secure attachment pieces together
from embedded pieces in pod fiberglass
Front Mounting Brackets (Two)
Rear Mounting Bracket (one)
Under belly attachment from
bracket to Pod (three)
Embedded in Top of Pod
Slides into underbelly attachment
Belly Plugs when Pod is not
attached
General Analysis
• Cosmos Express in Solid Works was used to
diagnose the stresses on parts
• Maximum forces were used with total weight of
Pod with load (120 lbs), with 4 G’s applied and
safety factor of 1.5. Total force of 720 lbs.
• C.G. of front loaded pod (two golf bags)
calculated
• 216 lbs on each front attachment and 288 lbs on
rear attachment.
General Analysis Cont.
• Total force in the direction of drag is estimated at
150 lbs. For 50 lbs on each attach point.
• As seen later this is 3.75 times the actual.
Means large safety factor.
• All bolts to the longerons and to the pod/belly
attachments are ¼ in.
• Screws to the belly bracket attachments are
3 in.
8
Allowable Loads
• Allowable Load=(Allowable Stress/Safety Factor)(Area)
• For Bolts and Screws of 304 Stainless Steel, Tensile
Strength Yield is used as 31200 psi, a shear strength of
half the yield is used, 15600 psi, though online sources
show it much higher, I will use a low number.
• Bolts through under belly attachments are in double
shear so we see an allowable load of 2297 lbs.
• Screws in Tension see the yield strength of 31200 psi,
we see allowable load of 2297 lbs as well. (since in
double shear we use twice the area and Yield strength is
twice the shear strength we see the same result.)
• These allowable loads are well above what the pod
would see.
Stresses in bolts to longerons
• Since there are two bolts into the longerons on each
front attachment we take the Total force on each bolt to
be 216/2 on the front for a force of 108 lbs. For the rear
bracket each bolt sees 72 lbs.
• These bolts have a smaller area so we see an allowable
load of 510.5 lbs in shear for each bolt.
• These requirements are met by the 304 Stainless Steel
bolts of ¼ inch diameter.
Deformation Picture of front
attachment
• Multiplied many times for show
• Safety factor of 2.47
Statistics
• Piece was run with both 304 S.S. and
Alloy 2018.
• 2018 is chosen because of lower weight
and higher yield
• Weight of Piece is .22 lbs
• Max Stress in Piece 18560 psi
• Max Displacement is .005 inches at base.
Deformation Picture of Rear
Attachment
• Lowest Factor of Safety in design is 4.82
Statistics
• Piece was run with both 304 S.S. and
Alloy 2018.
• 2018 is chosen because of low weight (3
times less) and higher yield
• Weight of piece is 1.4 lbs
• Max Stress in piece is 13880 psi
• Max Displacement is .005 inches
Deformation in Under belly
attachment to pod piece
• Safety Factor of 1.95
Statistics
• Piece was run with both 304 S.S. and Alloy
2018.
• 2018 is demonstrated here
• Data taken was for 288 lbs, so pieces are not
exclusive to one attach point, three identical
pieces.
• Weight of piece is .31 lbs
• Max Stress in piece is 1798 psi
• Max Displacement in piece is .00005 inches
Displacement of Embedded Pod
Piece
• Safety Factor 25.48
Statistics
• The piece was run testing both 304
Stainless and Alloy 2018.
• 2018 is recommended because of its
slightly higher yield strength and much
less weight
• Weight of piece is .32 lbs
• Max Stress in piece is 1804 psi
• Max displacement is .00005 inches.
Pod Statistics
• We would use a fiber glass pod, with 10 plies. Which would be a
thickness of .099 inches.
• To show an example model of deflection
• We were not able to accurately run this with fiberglass, this is using
2018 at .1 inches thick, max deflection is .02 inches.
Final Statistics
• Total weight of the attachment method is 3.73 lbs
• 304 SS would have worked for all pieces as well, and
even reduced some of the displacement, however, the
weight would have been significantly increase.
• 304 SS is used for bolts since that is a primary use of
304 SS.
• Alloy 2018 is chosen because it is a high strength alloy.
It is very easily machined and is a tough alloy that can
be used for heavy duty structural parts.
Conclusions
• The attachment methods as designed work for the support of the
cargo pod.
• Front attachments are placed on the inside of the longerons at 19
inches behind firewall and rear attachment is placed between
longerons at 69 inches behind firewall. Inspection of longerons
looked to be good placement.
• Would have liked to do further analysis on the Longerons and get
more accurate dimensions.
• Wish we would have nailed down a design sooner since a lot of the
semester was spent on investigation of workable/do-able pod
designs.
• Further work would include optimization of current design pieces
and trying different designs.
• I would like to thank my team and Steve Hampton for all the support
throughout the project!
Individual Report
• Mike Gavanda
• 70 hours
• Worked on
– Ground clearance
– Tail strike clearance
– Size requirements
– Pod access
Solid works attached Pod model
6:01 AM
Clearance
6:01 AM
Solid Works model
6:01 AM
Clearance/ Tail Strike Envelope
Pod wheel Clearance
6:01 AM
Golf Bag
Average Golf Bag Size
6:01 AM
Width
10 in
Height Bag
34 in
Height with clubs
50 in
Golf Bag Clearance
6:01 AM
Skis
Length (cm)
173
180
Side cut tip(mm)
130
135
Waist (mm)
96
99
Tail (mm)
124
125
Weight (g for one ski)
1970
2210
6:01 AM
http://www.salomonski.com/us/products/XW-Sandstorm-1-1-1-788918.html
Skis and pod
Access
Access Seal
Camloc 4002 Studs*
2600 and 2700 series made of steel
Shear: 1050 lbs. (ultimate)
Tensile strength: 700 lbs. (rated)
Rated to 450° F
Example of watertight hatch seal**
*www.aircraftspruce.com/catalog/hapages/camloc4002.php
**www.trimlok.com/detail.aspx?ID=933
Conclusion
• Meets clearance and size goals
– Clears fully loaded landing
– Clears tail strike
– Safe distance from exhaust
– Fits a pair of golf bags or 2 pairs of skis
• Easy access
Recommendations
• Find more on how the exhaust affects pod
• See if clearance can be increased for
landing and tail strike
• More study of water tight seal on access
door
Individual Report
• Cody Candler
• 75 Hours
• Tasks
– Location of the center of gravity
• Ensure it meets ground requirements
– Aerodynamics Analysis
– Range Optimization
Reference points of the front and back of the cargo pod while attached
(Figure 6-1 out of the Cirrus Manual)
C.G. of the aircraft with the pod attached
C.G. of pod located at FS 148.0
Sample Loading
• Pilot – 200 lbs
• Passenger – 200 lbs
• Fuel – 486 lbs (full tank)
• Cargo Pod – 100 lbs
Center of Gravity Limits
• No Luggage
• Luggage – 25 lbs
• Luggage – 50 lbs
Moment Limits
Estimate CD for cargo pod
Used Component Buildup Method out of Aircraft Design: A
Conceptual Approach by Raymer
Approach used:
Find flat-plate skin-friction drag coefficient (Cf)
–
Assumed complete turbulent flow
Cf 
0.455
log 10 R 
2.58
1  0.144M 
2 0.65
Find the component “form factor” (FF)
–
–
estimates the pressure drag due to viscous separation
assumed the pod to be a fuselage

60
f 


FF  1  3 
600 
f

–
–
where
f 
l

d
l
4 /  Amax
Amax is the maximum cross-sectional area of the pod which is 3.224 ft2
l is the length of the cargo pod (6.583 ft)
CD Estimate cont…
Determine interference effects on the component drag (Q)
–
Raymer says if the component is mounted less than one diameter away from
the fuselage then the Q factor is 1.3
Find the wetted area (Swet)
–
Total exposed surface area
 Atop  Aside 
  29.674 ft 2
S wet ~
 3.4
2


Calculate total component drag
C 
D0 subsonic

C f  FF  Q  S wet
S ref
Sref of SR-22 wing is 144.9 ft2
Result:
CD = 0.002577
Extra power needed with pod attached
•
Use general power required equation
PR = TRV∞
•
In steady, unaccelerated flight
TR = Drag (in our case, drag is increased drag from pod)
•
For each altitude, I used the cruise performance data from the Cirrus manual
–
I only used data where engine was operating at 2700 RPM since the engine has a rating of 310
hp at 2700 RPM
This gives a conservative estimation of the additional power needed to travel at the same
velocity with the pod attached as when it isn’t attached
25
8
7
20
6
5
15
4
10
3
2
5
1
0
0
2000
4000
6000
8000
10000
Altitude (ft)
12000
14000
16000
0
18000
Percent Power Increase
Additional Horsepower
–
Effects on Velocity
•
Calculate an approximate CD of the SR-22 using the cruise performance data out of the
Cirrus manual
•
Add the cargo pod component drag coefficient to the total aircraft drag coefficient
•
At 2700 RPM and same power, calculate velocity of aircraft with the pod attached and
without the pod attached
Result
• 7% decrease in velocity with the pod attached
320
315
310
Velocity (ft/s)
305
300
Velocity w/o Pod
295
Velocity with Pod Attached
290
285
280
275
270
0
5000
10000
Altitude (ft)
15000
20000
Sample Pressure Distribution
on Pod
Sample Pressure Distribution on the pod with a crosswind
Crosswind
Crosswind
Maximum Speed with Cargo Pod Attached
Conditions:
•Get to a location as fast as possible
•4 hours endurance
•81 gallons of usable fuel
•Weight: 3400 lbs
•Take off from sea-level
•No wind
Results w/o Pod:
Optimal Cruise Altitude: 12000 ft
• Fuel to taxi: 1.5 gal
• Fuel to climb: 4.4 gal
• Fuel to cruise: 59.8 gal @ 15.4 GPH
• 45 min IFR fuel reserve: 9.8 gal
• Airspeed: 178 KTAS
• Range: 785 nautical miles
Adjusted results for attached cargo pod:
• Airspeed: 166.4 KTAS (7% reduction)
• Range: 730 nautical miles
• Endurance of 4.3 hours
Maximum Range with Cargo Pod Attached
Conditions:
• Maximum range
• 81 gallons of useable fuel
• Weight: 3400 lbs
• Takeoff from sea level
• No wind
Results w/o Pod:
Optimal Cruise Altitude: 14000 ft
• Fuel to taxi: 1.5 gal
• Fuel to climb: 5.3 gal
• Fuel to cruise: 57.8 gal @ 11.3 GPH
• 45 min IFR fuel reserve: 9.8 gal
• Airspeed: 169 KTAS
• Range: 1006 nautical miles
Adjusted results for attached cargo pod:
• Airspeed: 143.7 KTAS (7% reduction)
• Range: 935 nautical miles
•Endurance of 5.8 hours
Conclusions
• Due to the restriction of the center of gravity of the cargo pod (FS
148.0) a weight of at least 25 lbs must be added to the luggage
compartment for the SR-22 to be safe to fly
• A 4 – 8% increase in power is needed to travel at the same speed
with the cargo pod attached as it would without the pod attached
• The cargo pod decreases the velocity of the SR-22 by approximately
7% when attached
• The maximum range of the SR-22 with a full tank of fuel and the
cargo pod attached is 935 miles
• The customer would need to sacrifice range or use more fuel when
operating with the cargo pod attached
Recommendations
• Mesh top of pod to the bottom of the fuselage to
reduce the drag area and increase performance
– Free up room to move the pod further back on the
fuselage, which would move the C.G. aft and maybe
eliminate the need for a requirement of 25 lbs of
luggage
• Spend more time studying pressure hot spots
– Contour the front of the pod more to further reduce
drag
– Revise the back half of the pod to prevent flow
separation and reduce drag
Individual Report
• Dan Poniatowski
• 86 hours of work
• Accomplishments
– Documented and managed schedule and Gantt Chart
– Documented requirements
– Facilitated communication between the team and the
sponsors
– Coordinated trips to the Cirrus factory in Duluth
– Facilitated FMEA and Environmental/Societal Impact
analysis
– Produced a Design Summary for the belly pod
consistent with Cirrus’ method of documentation
Failure Modes and Effects Analysis
Problem
Probability
Severity
High Lift Device Flutter due to failure
Low
High
Pull Parachute.
High Lift Device Flutter due to
aerodynamics
Medium
High
Test for natural frequencies. Avoid frequencies of prop and install
dampening.
Cable/Mechanical Failure
Low
High
Pull Parachute.
High Lift Device
Extension/Retraction Failure
Low
Low
Install mechanical indicator to inform pilot.
Medium
Medium
Install warning placards and mandate anti-spin pilot training.
High Lift Device Detachment
Low
High
Design fasteners to release when a partial failure occurs. Pull Parachute.
Icing
High
Varies
Collision Damage
Medium
Medium
Wing Detachment
Low
Very High
Internal Fuel Leak
Low
Medium
External Fuel Leak
Low
Low
Lightning Strike
Medium
Medium
Heat Damage
Medium
Low
Probability
Severity
Medium
Low
Low
High
Medium
Low
High
Medium
Medium
High
Designed to withstand a 3G manuever.
High
High
Warn the pilot in the Pilot's Operating Handbook and install placards.
Spin Entry
Problem
Pod hits the ground
Partial Attachment Failure
Foreign Object Collision
Front End Overheating
High G Failure
CG Out of Balance Due to
Loading
Mitigation
Incorporate existing deicing equipment into new design.
Reinforce leading edge. Pull Parachute.
Pull Parachute.
Install fluid detector and warning device.
Instruct pilot to deactivate electronics and land immediately.
Instruct pilot to land immediately.
Install dissipating mesh in the wing and high lift devices.
List warnings in Pilot's Operating Handbook.
Mitigation
Fasteners designed to shear off and release pod.
Remaining attach points designed to shear off.
Reinforce the nose of the pod.
Attach a metal heat sheild to the nose.
Environmental, Societal, and Global Impacts
Problem
Category
Severity
Mitigation
High performance wing causes society to
distrust general aviation as a result of
accidents.
Society
Low
Press releases on the advantages of the new wing design.
Wing performs well enough to edge
competitors out of the market.
Global
Low
Sharing of new wing technology.
Complexity of high lift device
design deters new pilots.
Society
Low
Simplification of pilot interface.
Problem
Category
Severity
Pod is used for smuggling drugs.
Society
Low
Pod is used by terrorists to deliver
weapons.
Society
High
Pod is used as a chemical distribution
tank.
Environment
Medium
Additional power required for use of pod
consumes more fuel.
Environment
Very Low
Mitigation
Make pod easy to remove when not in use.
Pod Design Summary
• Follows Cirrus’ Method of Documentation
• Documents design requirements and
goals.
• Documents the design concepts along
with pros, cons, risks and mitigation.
• Documents the design process to provide
insight to further investigation.
Pod Design Summary
Design Summary
ATA
: Add ATA 4 Digit CodeAdd ATA 4 Digit Code
Project
: SR24
Title
: SR-22 Cargo Pod
Author
: Daniel Poniatowski
Created
: Nov. 4, 07
Modified
: Dec. 12, 07
Concept 2: Streamlined Closed Pod.
Sketch
Pod Design Summary
Pros

Excellent aerodynamic performance

Holds goal cargo in one pod

Excellent Aesthetics
Cons

Sealing the pod to the fuselage is high risk.

Pod has poor utility.

Pod is not optimized for user friendliness.
Risks & TBD & New Items
1. Sealing the pod to the fuselage is expensive and prone to major failure during use.
2. Pod will not be a success with consumers because it is difficult to use.
Risk Mitigation
1. Change design to a closed pod to remove the need for a seal system.
2. Closed pod design will increase user friendliness and accessibility. Aerodynamics has become secondary
to utility, safety and user friendliness.
3
Detail Design / Model
Drawing File

File Names:
Key Characteristics
1. Pod satisfies design requirements.
2. Pod satisfies design goals.
3. Pod has acceptable aerodynamic performance while optimizing user friendliness and utility.
4. Pod is optimized for ease of production and profit.
5. Pod is optimized for ease of removal to give the consumer flexibility and increase satisfaction.
Compromises
1. Less than optimal aerodynamic performance.
2. Pod is less stylish than previous designs.
Design Review: Comments & Sign Off.
Text.
Design CE:
____________________ Date: ________________
Tool Lead:
____________________ Date: ________________
Production Lead:
___________________ Date: ________________
Conclusions and
Recommendations
• Gantt chart was useful for planning purposes
• Wiki was useful for common file sharing
• Requirements were recorded in a common
location, a more stringent process would be
useful.
• Schedule more time for risk mitigation
• Schedule more reviews during the design
process
• Be more aggressive in achieving results and
ensuring metrics are being met.
Download