- Beechcraft Baron 58
- Coleman Panther Navajo
- Piper Seneca III (PA-34-220T)
- Riems – Cessna F 406 Caravan
- Cessna 208 Caravan
- Cessna 310
Comparison
The results of plotting empty weight vs. gross weight are as follows:
FUSELAGE
Construction of the fuselage is of conventional formed sheet metal bulkhead, stringer and skin design. Inside cabin dimensions are 4.4 ft high and 5.4 ft wide at the front and rear spar bulkhead locations. Total length of the cabin from the front to the aft bulkhead is 35 ft 7 in. The cabin floor is flat with the exception of 2 feet in the aft cabin. This section is 5 inches above the main floor and makes up the aft cabin baggage area. The crew area is separated from cargo area by a cargo barrier/net system. The barrier and nets prevent loose cargo from moving forward into the pilot’s and the front passenger’s stations during an abrupt deceleration. The cargo barrier nets consist of three nets: one for the left sidewall, one for the right sidewall, and one for the centre. Entry to, and exit from the airplane is accomplished through an entry door on each side of the cabin at the pilot and front passenger seat location. A large cargo door is provided on the left side of the airplane. All doors can be opened with flaps up or down. The left crew door incorporates a conventional door handle, key operated door lock, conventional interior door handle and window with small triangular foul weather window. The foul weather window may be opened for additional ground ventilation. The right crew entry door incorporates a conventional outside and inside door handle and a manually operated inside door lock. The doors have a maximum width of 35.5 inches and a maximum height of 45 inches. Both doors will open 180 degrees forward to latch against the side of the fuselage. The primary opening is the two-piece cargo door installed on the left side of the airplane aft of the wing’s trailing edge. The cargo door is divided into an upper and lower section. When opened, the upper section swings upward and the lower section opens 180 degrees forward providing a large 49 in wide by 50 in high opening in the side fuselage which facilitates the loading of bulky cargo into the cabin. The door is flush with the floor and has square corners for maximum cargo loading capability.
COMPARISON CALCULATIONS
In the above comparison chart, many calculations had to be made. The calculations are as follows:
Baron 58
S = Wing Area
W = Weight
P = Shaft Horse Power
B = Wing Span
SHP = Shaft Horse Power
THP = Thrust Horse Power
ρ = rho
- Wing loading
Wing loading = W
S
= 5500 lbs
199.2 ft2
= 27.6lbs/ft2
Wing loading for the Baron 58 is 27.6 lbs/ft2
- Payload
Payload = Gross Weight – Empty Weight – (0.5 × METO) – Standard Male
= 5500lbs – 3481lbs – (2 × 300 × 0.5) –182lbs
= 5500lbs – 3481lbs – 300 – 182lbs
= 1537 lbs.
The maximum payload for the Baron 58 is 1537 lbs.
- Power Loading
Power Loading = W
P
= 5500lbs
600 SHP
=9.2 lbs/SHP
Power loading for the Baron 58 is 9.2 lbs/SHP
- Empty Weight Fraction
Empty Weight Fraction % = Empty Weight
Gross Weight
= 3481 lbs × 100
5500 lbs
=63%
Empty weight fraction for the Baron 58 is 63 %
- Aspect Ratio
Aspect Ratio = b2
S
= (37.833)2
199.2ft2
= 7.2
Aspect Ratio for the Baron 58 is 7.1
-
CLmax
q = 0.5 ρ v2
= 0.5 (.00238)(75 × 1.688)2
= 19.1 ft/s
CLmax = W .
= q × S
= 5500lbs .
(19.1)(199.2)
= 1.45
CLmax for the Baron 58 is 1.45
- Coefficient of Drag
Coefficient of Drag = 500 × 0.8 × SHP × 0.75 ×2
ρ (S (1.47 × v) 3)
= 500 × 0.8 × 600 × 0.75 ×2
.00238 (199 (1.47 × 163) 3)
= 0.055
Coefficient of Drag for the Baron 58 is 0.055
- Coefficient of Induced Drag
CDI = 48220 (wing loading)2
Aspect Ratio (.8) (v4)
= 48220 (27.6)2
(7.2)(.8)(163)4
= 0.0090
The CDI for the Baron 58 is 0.0090
- Zero Lift Drag Coefficient
CD0 = CD - CDI
= 0.055 - 0.0090
= 0.046
CD0 for the Baron 58 is 0.46
- Specific Fuel Consumption
Specific Fuel Consumption = US Gallons × 6 .
SHP × (range/ cruise)
= 194 × 6 .
600 × (1411 ÷ 163)
= 0.22
The Baron 58 has a specific fuel consumption of 0.22 lbs/hp/hr
*Note: checked data and can’t explain why the Baron 58 SFC is so low
The calculations for the other aircraft were completed in the same manner.
AIRCRAFT SIZING
Useful Load
Now that a good look has been taken from the competition it’s time to select the specifications for our aircraft. The company has decided that it would like to carry 1,000 lbs payload with a standard male and full of fuel. Our target cruise speed of 180 Kts will require approximately 5.5 hours of flying time. We also wish to add 45 minutes of reserve fuel. Therefore the total fuel time required is as follows:
Fuel Time = 1000 + 0.75
180
= 6.25 hours
Judging form the competition we have approximated a total of 700 SHP required for Buddy to do the fuel calculations. Now we can calculate the total load:
Pilot 182 lbs
Payload 1000 lbs
Fuel (700 × 0.5 × 6.25) 2188 lbs
Total 3370 lbs
Empty/Gross Weights
From the comparison aircraft, an average empty weight of 60% is calculated. The gross weight can be calculated as follows:
Gross Weight = Total Load
40%
= 3370
40%
= 8425 lbs
Therefore Buddy will have a gross weight target of 8425 lbs and an empty weight of 5055 lbs.
Wing Area
The comparison aircraft had an average wing loading of 29.4 lbs/ft2. Wing area requirements can be calculated in the following manner:
Wing Area = Gross Weight
Wing Loading
= 8425
29.4
= 286 ft2
Buddy will have an approximate wing area of 286 ft2.
Wing Requirements
Having found our required wing area and aircraft use, further wing design can be discussed. The span can be chosen. Buddy has to be fairly maneuverable; therefore we don’t want too long a span. From the comparison aircraft it is felt approximately 50 ft wingspan would be in order. If the Buddy had a longer wingspan it would be difficult to manufacture and would take away from our fuel capacity. A longer wingspan would increase the aspect ratio and therefore increase its stall speeds. Due to the utility function of Buddy, we won’t incorporate taper or sweepback wings. Both taper and sweepback designs tend to increase the aggressiveness of the stall characteristics. The Buddy’s wings will be designed with a slight washout, for better stall control. Buddy can’t get too complicated due to its size and function, therefore it will have plain flaps. Flaps can extend to 30o for low landing speeds.
Airfoil Sections
From the NACA report it was decided to use the following airfoils: 23018, 23012, 23015. The airfoil that best fits Buddy’s design is the 23018. This airfoil has better stall characteristics and is thick enough for easy manufacturing. It is also thicker for fuel loading. The CLmax of the three chosen airfoils are very similar.
For the NACA 23018 airfoil the following numbers apply:
CLmax = 1.42
CL(cruise) = 0.13
CL = 0.13
CD 0.0074
= 17.6
POWER REQUIREMENTS
With out aircraft specification entered into the “Aircraft drag and power required calculator” it is discovered Buddy requires 615.6 THP @ 180 Kts. The SHP can now be calculated:
Shaft Horse Power = THP
η(prop)
= 615.6
0.8
= 768.7 SHP
Our aircraft requires a total of 770 SHP. From this information we have chosen to equip Buddy with 2 Pratt & Whitney 385 SHP turbo-charged engines.
AIRCRAFT PEFORMANCE
Buddy’s zero-lift drag coefficient is calculated in the following manner:
- Coefficient of Drag
Coefficient of Drag = 500 × 0.8 × SHP × 0.75 ×2
ρ (S (1.47 × v) 3)
= 500 × 0.8 × 770 × 0.75 ×2
.00238 (286 (1.47 × 180) 3)
= 0.0403
Coefficient of Drag for the Buddy is 0.0403
- Coefficient of Induced Drag
CDI = 48220 (wing loading)2
Aspect Ratio (.8) (v4)
= 48220 (29.46)2
(8.74)(.8)(180)4
= 0.0057
The CDI for the Buddy is 0.0057
- Zero Lift Drag Coefficient
CD0 = CD - CDI
= 0.0403 - 0.0057
= 0.0346
CD0 for the Buddy is 0.0346
From Buddy’s performance numbers the following induced, parasitic, and total drag versus true airspeed is produced:
The minimum drag value, L/Dmax and minimum airspeed has been shown on the graph above.
From our aircraft information the following power required vs. true airspeed graph has been produced:
The minimum power required and best range power setting has been marked on the graph above.
Climb Performance
Best rate of climb is when excess power is at maximum as shown on the graph below:
Rate of Climb = Pavailable - Prequired × 33000
Weight
= 770 SHP × 0.8 – 205THP × 33000
8425
= 1610 ft/min
Therefore Buddy would climb at a rate of 1610 ft/min at sea level. The clean stall speed has been marked on the graph above.
SUMMARY
Our aircraft is a non-pressurized twin piston turbo charged high winged with retractable landing gear. The aircraft is certified for two persons including minimum crew of one. The power plant consists of two Pratt and Whitney of Canada piston turbo charged engines mounted on the leading edges of each wing. Certification basis is to North America FAA FAR requirements: day, night, VFR, IFR and flight into icing conditions when equipped with appropriate options.
Design Weight and Capacities:
Maximum Ramp Weight 8455
Maximum Takeoff Weight 8425
Maximum Landing Weight 8250
∗Standard Empty Weight 5055
Maximum Weight into icing 8300
Capacities:
Maximum Fuel 375 Gallons
Usable Fuel 365 Gallons
Oil 14 Qt.
Power plant
Pratt and Whitney 385 @ 2300RPM
Propeller:
McCauley Constant Speed Full Feathering, Reversible, 3 blades, 91 in. Diameter
Loading:
Wing 29.5 lbs/ft2
Power 10.9 lbs/HP
Approximate Dimensions:
Overall Height 15 Ft 5 in
Overall Length 41 ft 7 in
Wing
Span (overall) 50 ft
Area 286 ft2
Sweepback 0o
Dihedral 2o
Aspect Ratio 8.74
Cabin
Height (footboard to headliner) 4.4 ft
Length 17 ft
Width 5.3 ft
Landing Gear
Tread 11.66????
Wheelbase 14.5
Tire Size (main) 9 × 10, 60 psi
Tire Size (nose) 22×9, 40 psi
PERFORMANCE
Performance figures are based on the indicated weight, standard atmospheric conditions, level hard-surface dry runways and no wind. They are calculated values derived from flight tests conducted by the manufacturing company under carefully documented conditions and will vary with individual airplanes and numerous factors affecting performance.
Speed (max ramp weight in lbs.):
Maximum Cruise at 10,000 ft. 175
Range
With 2190 pounds usable fuel and fuel allowance for engine start, taxi, takeoff, climb, descent and 45 minutes reserve
Maximum Cruise Power @ 10,000 ft. 860 NM
Maximum Range Power @ 10,000 ft. 960 NM
Rate of Climb
Sea Level 1610 ft/min
Takeoff Performance
(Sea level, take off weight)
Ground roll 1400 ft
Total Distance over 50ft. Obstacle
2500 ft
Landing Performance
(Sea level, max landing weight, no reverse)
Ground Roll 915 ft
Total Distance over 50 ft. Obstacle
1740 ft
Stall Speed
Flaps Up, Idle Power 74 Kts
Flaps Down, Idle Power 64 Kts
CONCLUSION
Now that Buddy has been created and designed on paper in this formal report, we can search out investors and manufacturing ideas. With hard work and persistence we can make Buddy a reality, which in turn will make J&E Air Cargo Specialists a reality. With the success of J&E Air Cargo Specialists our future plans may change with the continually transforming aviation industry. Who knows J&E Air Cargo Specialists may be the next FedEx.
∗ Standard Empty Weight Includes unusable fuel, full operating fluids and full engine oil