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PROPOSALQuetzal-VTOL

INSTITUTO POLITÉCNICO NACIONAL

UNIDAD PROFESIONAL INTERDISCIPLINARIA DE INGENIERÍA CAMPUS GUANAJUATO

INSTITUTO POLITÉCNICO NACIONAL

UNIDAD PROFESIONAL INTERDISCIPLINARIA DE INGENIERÍA CAMPUS GUANAJUATO Av. Mineral de Valenciana No. 200. Fracc. Industrial Puerto Interior Silao de la Victoria, Guanajuato, Mexico.

Quetzal-VTOL Team

Developed as coursework for: Tópicos Selectos de Ingeniería II (Helicopter Design)

In response to the 31st Annual Student Design Competition of the American Helicopter Society

Faculty Advisor: KARAS Ondrej

CASTRO OLGUÍN Ana Cecilia

GASCA FLORES Jesús Francisco

GONZÁLEZ ONTIVEROS Karim Gilberto

IXTA BERNAL Axel Paul

MARTÍNEZ CASTILLO Fernando

OLMEDO GONZÁLEZ Adriana Paola

Table of ContentTheoretical Frame................................................................................................................. 3Overview Information...........................................................................................................3

Proposal Roadmap.............................................................................................................3Requirements of proposal.....................................................................................................4Preliminary Design................................................................................................................4

Power Plant........................................................................................................................ 4Airfoil................................................................................................................................. 5Preliminary VTOL Configuration.........................................................................................6

Calculations.......................................................................................................................... 6Wing Surface..................................................................................................................... 6Control Surfaces................................................................................................................ 6Power Required.................................................................................................................7

Flight Envelope.....................................................................................................................7Mission.................................................................................................................................. 7References............................................................................................................................ 9

THEORETICAL FRAME

VTOL is an abbreviation for vertical take-off and landing. This aircrafts have the ability to take off and land without a runway. In vertical flight, lift thrust is provided either by turbojet or turbofan engines. [1] The first practical VTOL was Hawker Siddeley Harrier. The motivation behind creating VTOL is to produce a craft capable of vertical takeoff, like a helicopter, while retaining the desirable features of fixed wing aircraft, such as

high cruise speeds.

There are two methods for VTOL technology, tiltrotor mechanism and vector thrusting.

A vector thrusting manipulates the direction of the thrust of engines to control the angular velocity.

In a Tiltrotor mechanism the aircraft have a couple powered rotors mounted on a rotating shaft at the end of fixed wing. For vertical flight rotors are angled so the plane of rotation is horizontal. As the velocity of the aircraft increased the rotors are tilted forward, with the plane of rotation in vertical direction.

Some VTOL aircraft can operate in other modes, such as CTOL (conventional take-off and landing), STOL (short

take-off and landing), and STOVL (short take-off and vertical landing).

A VTOL aircraft should possess a stable design, the thrust to weight ratio must be greater than one, and it should be stable while hovering and low speed; and conventional control surfaces are useless due to insufficient dynamic pressure. [2]

VTOL aircraft is preferred because it need very short runway and hanger which reduces the cost of runway, it doesn’t need conventional control surfaces which reduces the cost of the Airplane, VTOL aircrafts have high maneuvering ability and take off is very easy and low risk is there.

OVERVIEW INFORMATION

This is a proposal in attendance for the 31st American Helicopter Society Student Design Competition, which awards the innovation in design for specific requirements.

PROPOSAL ROADMAP

Goal of work: The main objective of the proposed research is to design and develop an innovating Vertical Take-Off and Landing aircraft, with better performance and capabilities than those existent nowadays.

Overcome the fundamental issues that limit vertical flight performance:

Retreating blade stall High parasite drag Low power loadings Inefficient lift in translational flight High empty weight fractions Vertical download

Figure 2. Yakovlev Yak-141. Use the technology vector thrusting.

Figure 1. Bell eagle eye. Use of a tiltrotor mechanism.

Losses due to interactional aerodynamics Power losses

REQUIREMENTS OF PROPOSAL

Table 1. Specific Objectives of the Project

Sustained high speed at true airspeed * 300 kts. - 400 kts

Hover efficiency25% of the Ideal Power Loading at

ISAL/DCRUISE ** >10

Useful Load Fraction >40%Payload Fraction >12.5 GW

* The 300-400 knots speed requirement is a sustained cruise capability, and not just a short duration dash speed.

** The criterion is a peak L/D for Vbr.

The technologies should be proven at relevant scale on a manned or unmanned flight demonstrator aircraft, which must have the following characteristics:

Table 2. Properties of the demonstrator

Demonstrator Aircraft Gross Weight

10000 lbs - 12000 lbs

Demonstrator Load Margins * -0.5g -- 2g

* The aircraft will be designed with sufficient load margins to be able to safely demonstrate maneuvers at least up to these load limits at maximum gross weight under different flight conditions. The accelerations are representative of being able to demonstrate maneuverability during takeoff, hover, transition to and from forward flight, and to perform coordinated turns, etc.

PRELIMINARY DESIGN

POWER PLANT

In order to select the best engine for helicopter configuration, we considered the parameters shown in table 3 and table 4, both GE CT700 and TV3-117VMA-SBM1V deliver the same power, but the first one shows to have a better weight to power ratio, so the second engine was discarded. The chosen engine was the TV7-117V, which allows to have a smaller and lighter rotor (see Fig. 3). Is important to observe that we supposed FM=.75.

Table 3. Engine Parameters Comparison

Table 4. Engine Parameters comparison

5 10 15 20 25 30 35 40 45 50 550

500

1000

1500

2000

2500

3000

3500

GE-CT700

TV7-117V

Rotor Radius [ft]

Pow

er P

i [H

p]

Figure 3. Power vs. Radius

Thus, the rotor would have radius=21 ft and the induced power would be 1350 HP.

AIRFOILThe airfoil for the wing was chosen after the analysis and comparison between five different airfoils. Their characteristics and the behavior of the CL in terms of the AOA for max L/D (cruise) and, and the CLmax (stall).

Table 5. Compared airfoils

NACA 64-214

NACA 63-212

NACA 66-210

ENGINE

Max. Power

SL [hp]

Cruise Power [hp]

SFC [lb/shp

hr]

Weight [lbs]

GE-CT700 1994 1500 0.465 456TV3-117VMA-SBM1V

2000 1500 0.485 650.36

TV7-117V 2800 2000 0.485 793.66

ENGINE W/P P*FM

GE-CT700 3.29 1125TV3-117VMA-SBM1V 2.31 1125TV7-117V 2.52 1500

NACA 63-208

NACA 64-212

Table 6. Comparison between airfoils, at cruise conditions.

CRUISE

Airfoil V [ft/s] CLbrAlfa[°]

S[ft2]

NACA 64-214 675 0.593 2.1 91.6

NACA 63-212 675 0.592 2 91.74

NACA 66-210 675 0.598 3 90.82

NACA 63-208 675 0.689 2.9 78.83

NACA 64-212 675 0.598 2 90.82

Table 7. Comparison between airfoils, at stall conditions.

STALL

Airfoil V [ft/s] CLmaxAlfa[°]

S[ft2]

NACA 64-214 220 1.473 15 130.33

NACA 63-212 220 1.475 15 130.15

NACA 66-210 220 1.479 15 129.80

NACA 63-208 220 1.389 14.5 138.21

NACA 64-212 2201.381 14.5 139.01

Considering this data, we can see that the airfoil NACA 66-210 allow us tu have the smallest wing area, so the next step is to plot the corresponding charts of this airfoil.

The airfoil for the wing is then NACA 66-210.

-5 0 5 10 15

-1

-0.5

0

0.5

1

1.5

ClCl

Figure 4. Lift curve for NACA 66-210 Airfoil.

0 0.02 0.04 0.06 0.08 0.1 0.12

-1

-0.5

0

0.5

1

1.5

Cl/ Cd

Figure 5. Polar curve for NACA 66-210 Airfoil.

PRELIMINARY VTOL CONFIGURATION

CALCULATIONS

WING SURFACEFor the wing plant form a Taper Ratio= 0.6 was selected because it makes the wing to approximate a lot to an elliptic one improving the Oswald’s factor value.

Since the higher the aspect ratio, the lower the induced drag, we selected a AR= 8 predicting that the structure will support the loadings and stresses but with the less induced drag possible.

As it is shown in the graph below (Figure 7), as the Aspect Ratio increases, the Lift coefficient also increases, but the slope of the lift curve, is reduced; so that, some of the advantages of this configuration are that the wing`s Aspect Ratio is big enough to have an efficient behavior, but not too large to decrease the structural limits.

0 2 4 6 8 10 12 14 16 180

1

2

3

4

5

6

7

CL_alpha vs. Aspect Ratio

Figure 7. Cl_alpha vs. Aspect Ratio

Applying Polhamus formula we knew the Clα of the wing:

Clα= 2 πAR

2+√[ A R2(1−M 2)K2 ]∗[1+

tan2 Λ .5

1−M 2 ]+4

=5.28

K=1.08

Based on the basic equation for lift, we obtain an equation in order to know the needed value for the wing surface.

L=12ρ v2CL S

S= 2 Lρ v2CL

S= 2∗11000 lbs

(8.9 x10−4 slugft3 )(220 ft

s )2

(5.28 )(.2762)

S=129.8 ft2

CONTROL SURFACES

We have to determine four parameters for the aileron design:

1. The aileron platform area Sa.2. The aileron chord and span ca, ba.

3. Maximum aileron deflection ±𝛿𝐴𝑚𝑎𝑥.

4. Location of inner edge of the aileron along the wing span bai.

Table 8. General statistics for aileron to wing ratios.

Sa/S 0.05-0.1ba/b 0.2-0.3ca/c 0.15-0.25bai/b 0.6-0.8

±𝛿𝐴𝑚𝑎𝑥 ±30°

Sa=(0.1)(129.8 ft2)

Sa=12.98 ft2

Sa2

=6.49 ft2

For the aileron span;

ba=(0.25)(b)

ba=(0.25)(39.54 ft )

ba=9.885 ft

ba2

=4.9425 ft

For the aileron chord;

ca=(0.25)(c )

ca=(0.25)(3.28 ft )ca= .82 ft

POWER REQUIREDFrom the parabolic drag equation we are able to calculate the power required since Preq= L for straight-leveled flight.

CD=CD0+ClπARe

CD=.022+ .2762π (8 )(.75)

=.026

D=.5∗6752∗8.89∗10−4∗130∗.026=686 lb

Preq=Dv326

=686∗400326

=841.44HP

RATE OF CLIMBThe procedure to obtain the Rate of Climb was found in reference [1]

CLBCR=√3CD0πAe

CBCR=√3 ( .0022 ) π (10.25 ) ( .75 )=1.26

v=√ 2WρSCLBCR

v=√ 2(11000 lb)

(.0765 lbft3

)(164 ft2)(1.26)=211.605 fts

CD=CD0+CLBCRπAe

CD=.22+ 1.26π (10.25 ) ( .75 )

=0.087

D=WCDCLBCR

D=( 11000 lbm )(32.174 fts2 )( 0.0877

1.26 )=24633.53lb f

THPreqd=Dv

THPreq=(24633.53 lbf )(211.605 fts )=5212578.11 lb ft

2

s3

RC=(THPav−THPreq)

W

RC=(16988160 lb ft

2

s3 −5212578.11 lb ft2

s3)

(11000 lb)(32.174 fts2

)=33.27 ft

s

FLIGHT ENVELOPE

MISSIONThere is a proposal for an application for the Quetzal-VTOL aircraft: Rescue and extraction either soldiers or civilians in war zones such as Aleppo, Homs, Damascus, Mosul, Arbil, Kirkuk, Baghdad and Kerbala.

Two bases are supposed to be located, one in Kuwait and the second one in Jordan.

Point A Point B Max. Range n.m (Max. Distance)

Base Kuwait Base Jordan 502.16Base Kuwait War zone (Iraq) 415.77Base Jordan War Zone (Syria) 415.77

Table 10. Mission fuel requirements per engine

Table 9. Mission Ranges

EngineRequired Mission 1

Fuel(503 NM) + 20 min reserve

Required Mission 2 & 3Fuel (415 NM) + 20 min reserve

GE 1221.212 lb 1029.90 lbTV3- 1271.3 lb 1072.50 lbTV7 1271.3 lb 1072.50 lb

Figure 8. Mission overview Map

Table 11. Mission I profile description

FIRST MISSIONTIME [MIN] CONDITION

Start-up/Warm-up/Taxi 10 Engine Idle, SLSHOGE Take Off 1 95% Max. Power, SLSClimb 15 To Best Alt., Vbroc

Cruise 30 Best Alt., ISADescend To SLS, Vbroc

HOGE Land 1 95% Max. Power, SLSBoarding 3HOGE Take Off 1 95% Max. Power, SLSClimb 15 To Best Alt., Vbroc


HOGE Land 1 95% Max. Power, SLSShutdown/Taxi 5 Engine Idle, SLS

Figure 9. Mission I Profile Graphical Description.

Table 12. Mission II profile description

SECOND MISSIONTIME [MIN] CONDITION

Start-up/Warm-up/Taxi 10 Engine Idle, SLSHOGE Take Off 1 95% Max. Power, SLSClimb 15 To Best Alt., Vbroc


HOGE Land 1 95% Max. Power, SLSBoarding 3 Static GroundHOGE Take Off 1 95% Max. Power, SLSClimb 15 To Best Alt., Vbroc


HOGE Land 1 95% Max. Power, SLSBoarding 3 Static GroundHOGE Take Off 1 95% Max. Power, SLSClimb 15 To Best Alt., Vbroc


HOGE Land 1 95% Max. Power, SLSShutdown/Taxi 5 Engine Idle, SLS

Figure 10. Mission II Profile Graphical Description

Figure 11. Mission Profile Proposed in the Requirements Graphical Description.

Table 13. Mission Profile Proposed in the requirements.

Mission Segment Time [min] Condition

Start-up/ Warm-up/ Taxi 10 Engine Idle, SLSHOGE Take off 1 95% Max. Power, SLS

Climb To Best Alt. VbrocCruise Out 1 Vbr, Best Alt., ISA

Cruise Out 2 15 Max. Sustained Speed, 95% Max. Power, Best Alt., ISA

Descend To SLS, Vbroc

Mid Mission Hover 15 HOGE with Full Payload, 95% Max. Power SLS

Climb To Best Alt., Vbroc

Cruise In 1 15 Max. Sustained Speed, 95% Max. Power, Best Alt., ISA

Cruise In 2 Vbr, Best Alt., ISADescend Vbr, Best Alt., ISA

HOGE Land 1 95% Max. Power, SLSShutdown/ Taxi 5 Engine Idle, SLS

REFERENCES[1] Aircraft Aerodynamics and Performance. (p.p. 399) Jan Roskam. Design, Analysis and Research Corporation.

1997.

[2] Dragan Fly. Innovative UAV Aircraft & Aerial Video Systems [on line]. Update: 2014. [Accessed: 22 of February of 2014]. Available: http://www.draganfly.com/news/2009/05/13/all-about-vtol-uavs-and-vtol-aircraft/

[3] Juyal M., Prakash V., et al. Design and fabrication of VTOL engine. University of Petroleum and Energy Studies. 16th November of 2010.

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