Jay Carter, Founder &

CARTERAVIATION TECHNOLOGIES

An Aerospace Research & Development Company

Jay Carter, Founder & CEO

CAFE Electric Aircraft Symposium July 23^rd, 2017

www.CarterCopters.com

_©W₂₀i₁c_{5 C}h_Ai_Rt_TEa_{R A}F_Va_IATl_Il_Os_N,_TT_ECe_HNx_Oa_LOs_{GIES, LLC}

SR/C is a trademark of Carter Aviation Technologies, LLC

A History of Innovation

Built first gyros while still in college with

father’s guidance

Led to job with Bell Research & Development

Steam car built by Jay and his father

First car to meet original 1977 emission standards

Could make a cold startup & then drive away in less than 30 seconds

Founded Carter Wind Energy in 1976

Installed wind turbines from Hawaii to United

Kingdom to 300 miles north of the Arctic Circle One of only two U.S. manufacturers to survive

the mid ‘80s industry decline

SR/C™ Technology Progression

2013-2014 DARPA TERN

Won contract

over 5 majors

2009
License Agreement with AAI, Multiple Military Concepts

2011
2^ndGen First Flight Later Demonstrated
Find a Manufacturing
Partner and Begin
Commercial Development

L/D of 12+

2005 1^stGen

L/D of 7.0

1^stGen

First flight

1994 - 1997 Analysis & Component

Testing

22 years, 22 patents + 5 pending

11 key technical challenges overcome Proven technology with real flight test

1994 Company

founded

SR/C™ Technology Progression

Quiet Jump Takeoff & Flyover at 600 ft agl

Video also available on YouTube: https://www.youtube.com/watch?v=_VxOC7xtfRM

SR/C vs. Fixed Wing

• SR/C rotor very low drag by being slowed

Profile HP vs. Rotor RPM, PAV Rotor

Drag per WADC TR 55-410:

@ 250 kts @ SL

³1 4.6²

₀

C_DA

400 300 200 100

₀

HP 

HPo - Full HPo - Rot Only

Rotor RPM

• SR/C wing very small because rotor supports aircraft at low

speeds – wing can be sized for cruise

• Fixed-wing wing must be sized for low speed/landing • SR/C slowed rotor & small wing equivalent to fixed-wing’s

larger wing

SR/C Electric Air Taxi

Ø34’

SR/C Electric Air Taxi– Features

Slowed rotor enables

10’ diameter scimitar

tail prop rotates to provide counter torque for hover or thrust for forward flight
High inertia, low disc loaded rotor acts as

built-in parachute, but

safer because it works at any altitude /
Lightweight, low profile, streamlined

tilting hub greatly

reduces drag. No spindle, spindle high speed forward flight, low drag, low tip speed/noise, no retreating blade stall speed, and provides directional control housing, bearings or lead-lag hinges

Tall, soft mast isolates

airframe from rotor vibration for fixed-wing smoothness

Tilting mast controls

aircraft pitch at low speeds & rotor rpm for high cruise efficiency at high speeds

Mechanical flight

control linkages to optional pilot in parallel with actuators for true redundancy
Extreme energy absorbing fail safe landing gear up to
30 ft/s improves landing safety

Simple, light,

structurally efficient wing with no need for high lift devices
High aspect ratio wing with area optimized for cruise efficiency
Battery pack in nose to balance tail weight

Performance Parameters

Drag coefficients based on actual achieved data, not expected improvements 3200 lb empty weight with batteries 4000 lb max gross weight (800 lb max payload)

300 W-hr/kg battery energy density

Assumed margin for 0.5 Empty Weight Fraction at 600 ft/s tip speed Mission: 30 sec HOGE for takeoff, Climb at Vy to 5k ft, Cruise at 175 mph,
Descend at Vy, 2 min HOGE at landing (no reserve)

Empty Wt (w/o batteries) vs. Rotor
Hover Tip Speed
Range at 175 mph vs. Payload for
Various Hover Tip Speeds

2250 2200 2150 2100 2050 2000 1950
200 180 160 140 120 100
80

2213 lbs
159 miles

D=46 miles

113 miles

D=213 lbs

600 ft/s 550 ft/s 500 ft/s

450 ft/s

2000 lbs

Note: 150 mph cruise will extend range by ~10% at 800 lb payload

Air Taxi Concept Comparison

• Compared three different configurations
• SR/C • Hex Tilt Rotor

• ‘T’ Tilt Rotor

• Used common assumptions and methods for all three concepts
• Based drag coefficients and parameters

on measured flight data from PAV

Carter PAV L/D vs. IAS

Hex Tilt Rotor

Meas'd

Model
642

IAS, mph

Actual Measured Flight Data

Note: Data scatter mostly attributable to gathering data when developing rotor rpm / mast control algorithms and varying rotor rpm considerably

‘T’ Tilt Rotor

Analysis Methods & Assumptions

200 lbs per person

4 people max

Pilot/Pax Weight

(top 10% unuseable with rapid charge, bottom 10% unuseable to avoid current spike)

Useable Battery Capacity
Scaled Linearly with Max Continuous Power

Assumed motor could be overloaded 1.87x for 30 sec for OEI

Limited current to 40 amp per wire, running multiple wires per leg to reach full current required. Per N.E.C., used AWG-10 with Class C Insulator
Wiring Weight
Used same coefficients on all concepts & appropriately scaled misc drags as derived from calibrating model to actual flight data from PAV
Drag Coefficients Hover Typical Mission
Hover Out of Ground Effect (HOGE) at 6k ft with 1.1x margin
30 sec hover, climb, cruise, descent, 30 sec hover

120 sec hover, climb, cruise, descent, 120 sec hover

+Reserve: 120 sec hover, 2nm divert, 120 sed hover
Planning Mission

Common Footprint

• Footprint driven by interface with vertiports

• If certain size footprint can be justified, justification is applicable to all technologies

• Single Rotor SR/C & Hex Tilt Rotor have similar disc loadings

• ‘T’ tilt rotor has very high disc loading

‘T’ TR Hex TR SR/C

Rotor Area, ft² Disc Loading, lb/ft² Total Hover HP

30 sec OEI HP

Cruise HP at 175 mph
144.9
27.6
774.0

1869.6 467.8

240 240
791.5
5.1
368.4
907.9
4.4
424.0

•••

‘T’ TR Rotor Area only includes 4 lifting rotors (tails rotors for trim control only)

SR/C Total Hover HP includes tail rotor power to counter torque All Hover HPs include 10% lift margin

Comparison Preliminary Results

• ‘T’ Tilt Rotor has very high HP required due to disk loading – higher empty weight for installed HP • SR/C has better L/D @ 175 mph due to smaller wings & less wetted area from prop spinners, fuselage, & no LG sponsons

2,100 2,050 2,000 1,950 1,900

1,800 1,750

180 160 140 120

80 60 40 20

0
SR/C - 40 ft

SR/C - 37 ft SR/C - 34 ft Hex TR - 40 ft Hex TR - 37 ft Hex TR - 34 ft 'T' TR - 40 ft 'T' TR - 37 ft 'T' TR - 34 ft
SR/C Hex TR T TR

1.4 1.2
1
SR/C - 40 ft

SR/C - 40 ft

SR/C - 37 ft SR/C - 34 ft Hex TR - 40 ft Hex TR - 37 ft Hex TR - 34 ft 'T' TR - 40 ft 'T' TR - 37 ft 'T' TR - 34 ft
SR/C - 37 ft

SR/C - 34 ft

Hex TR - 40 ft Hex TR - 37 ft Hex TR - 34 ft 'T' TR - 40 ft 'T' TR - 37 ft 'T' TR - 34 ft
0.8

0.4 0.2

True Airspeed, mph

Payload, lbs

Comparison Preliminary Results

• SR/C has farthest range with least energy used in typical mission,

due to better L/D at 175 mph

• ‘T’ Tilt rotor has low useable energy because of high empty weight

fraction. Has low percentage of energy available for cruise because

of high HOGE power requirements for planning / reserve.

Useable Energy Budget, 800 lb payload, 34' width

180 160 140
R3. Reserve 2 min HOGE
120

100
80 60 40 20

R2. 2 nm reserve at best endurance R1. Reserve 2 min HOGE

Reserve

P1. 90 sec + 90 sec add'l HOGE for planning

5. 30 sec HOGE

Add’l HOGE for Planning

4. Descend to Ldg Altitude 3. Cruise at 5000 at 175 mph 2. Climb at Max ROC to Cruise Alt 1. 30 sec HOGE

Typical Mission

Extreme Energy Absorbing Landing Gear

• Extreme energy absorbing – 24” stroke for

Carter Smart Strut

descent rates up to 24 ft/s at touchdown
• Responds to impact speed for near constant

Belleville Stackup to control valve to keep pressure on piston near constant based on impact

deceleration across full throw of gear
• No rebound – no bouncing • Proven technology – used on all Carter

Air Over

Hydraulic for

Energy

prototypes
• Lightweight due to efficient energy absorption

Absorption

velocity

PAV Single Strut Design
Energy Absorbing
Cylinder
Automatic
Metering Valve

Hydraulic Pressure in
Lower Cylinder

for Gear Retract

Main Gear Trailing Arm

Torque Tube

Energy Absorbing Landing Gear Video

Video also available on YouTube: https://www.youtube.com/watch?v=MntCeJRl2YE

Energy Absorbing Landing Gear

Note near constant pressure over full stroke

100
95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10
5

Piston position (8.44" max) Valve position (.5" max) Pressure Top (3000 psi max) Pressure Bottom (3000 psi max)

Time (s)

Data from drop test shown in previous slide

Carter Scimitar Propeller

• Highly swept to reduce apparent Mach number

– Allows higher CL’s, faster tip speeds, & thicker

airfoils

– Swept tip reduces noise

• Twist a compromise between high speed cruise & static/climb

• Lightweight composites 1/2 to 1/3 the

weight of conventional designs

• 100” diameter prop shown weighs 42 lb

• Tested at Mach 1 for cumulative 10 minutes

• Wide chord – blade not stalled

• Spinner nearly flat at prop root

– Reduces decreasing pressure gradient, keeping good airflow on prop root

• Cruise efficiencies of 90+%

• Static/climb efficiencies on order of 30%

better than conventional designs

Scimitar Propeller – Bearingless Design

• Pitch change accomplished by twisting the spar • Eliminates spindle, spindle housing, and bearings used on conventional propeller – simple & lightweight

• Similar design used on Carter rotors which further eliminates lead/lag and coning hinges

Video also available on YouTube: https://www.youtube.com/watch?v=scrXVfwJ7hY

CARTERAVIATION TECHNOLOGIES

An Aerospace Research & Development Company

Jay Carter, Founder & CEO

CAFE Electric Aircraft Symposium July 23^rd, 2017

www.CarterCopters.com

_{SR/C is a trademark of Carter Aviation Technologies, L}1_LC9

Backup Slides

Mission Definition

• Using same typical & planning missions as McDonald and German*

• Typical mission for operating cost only requires 30 sec hover for T.O.

& landing
• Worst case mission for planning (i.e. charge required before taking

off to fly a given mission) requires 120 sec T.O. & landing for given

mission + 120 sec T.O. & landing for reserve + 2 nm reserve cruise
• For sizing, assuming 4 min continuous hover

*McDonald, R. A., German, B.J., “eVTOL Energy Needs

for Uber Elevate,” Uber

Elevate Summit, Dallas, TX, April 2017.

Cruise Performance Model

• Analysis conducted with Carter’s proprietary cruise analysis model

• For SR/C, developed mainly for cruise when rotor is unloaded

• Model calibrated to measured flight data for PAV. Inputs were scaled

Carter PAV L/D vs. IAS

appropriately for these concepts.

• Had to estimate drag contributions from different elements, since the aircraft is only instrumented to measure overall thrust*

• Interference & separation drags can

account for up to ~1/2 of total aircraft drag, and must be accounted for to allow accurate L/D prediction (based on flight test experience by Carter and

Bell Helicopter / Ken Wernicke)

Meas'd

Model
642

IAS, mph

• Air taxi analysis breaks flight into short segments, incorporating climb, descent, and reserves

Note: Data scatter mostly attributable to gathering data

when developing rotor rpm / mast control algorithms

and varying rotor rpm considerably
* Overall drag is calculated based on thrust adjusted for rate of climb/descent – report with methods is available

Battery Assumptions

• Using same rationale as

McDonald and German*

for useable battery capacity

• Top 10% & Bottom 10%

of capacity inaccessible

• 80% capacity accessible

DOD = Depth of Discharge

• Ignoring internal

resistance losses for this

analysis

Ignored for this analysis

*McDonald, R. A., German, B.J., “eVTOL Energy Needs for Uber Elevate,” Uber Elevate Summit,

Dallas, TX, April 2017.

Motor Overload Capacity

• Overload capacity very dependent on specific motor – see examples below from various

sources (only shown to illustrate behavior – these aren’t the motors being used)

• Model with a simple empirical curve that mimics those trends, where C is a constant

퐶
푇푖푚푒 =

퐼
− 1

퐼_{푟푎푡ꢀ푑}

• Based on text in ‘Uber Elevate’, assume a motor that can be overloaded 1.5x for 90 seconds

(paper stated 1–2 min). Matching above formula to that data point, C = 22.5

t, sec I/Ir

15 2.22

Thermal Limit assuming 90 sec @ 1.5x

120 100
80

30 1.87

45 1.71

60 1.61

90 1.50
120 1.43

240 1.31

480 1.22

1.87x for 30 sec OEI 1.31x for 4 min HOGE

I / I_rated

Data from manufacturer needed to improve this estimate

Empty Weight Estimation

• Weight estimate for all concepts used same methodology

• Structures & Equipment Groups based on method in
Chapter 15 of Raymer, Daniel P: Aircraft Design: A Conceptual Approach

• Structures weights multiplied by 0.50 to reflect gains from carbon-

Jay Carter, Founder &

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