NASA-CR-201062 Development for

and

Testing

High-Altitude

of Airfoils Aircraft

Final

Report ,f

for the September

Submitted

to:

Attn:

1,

Period

1994

NASA

-

May

Dryden

Steven

Yee,

31,

Flight

Grants

Research

Technical

Monitors:

Robert Fluid

Center

Officer

Contract Management MS D1044 Edwards,

1996

Branch/XAA

CA 93523-0273 Geenen,

and

Flight

Al

Bowers

Mechanics

Branch/XRA

MS D2033

Submitted

Grants

by:

Officer:

Department Massachusetts

of Aeronautics and Astronautics Institute of Technology

Cambridge,

MA 02139

Ms. (617)

Principal

Investigator:

Charlotte 253-3529

Associate (617)

Morse

Professor

253-0067

June

1996

Mark

Drela

1

Completed

Essentially addressed. posal

all the work proposed in the proposal has been Additional work on heat-exchanger aerodynamics

was

also conceived

A summary detailed results they

Work

became

are given

and

executed

with

the

agreement

completed or adequately not in the original proof the

Technical

Monitor.

of the specific tasks accomplished is given below. The corresponding have been transmitted to Dryden personnel via e-mail as soon available.

in the

All e-mail

Appendices,

transmissions

along

with

have

relevant

been

plots,

saved,

figures,

and

and

the

papers

as

key ones

which

were

generated.

1.1

Airfoil

The

Apex-16

tended

design airfoil

altitudes,

In the

course

Mach

number

airfoil

thickness,

of the

optimization

numerous

1.2

and

for that

identified

be required,

condition

(by

the

target

candidate

dictable

behavior

NACA

1410

APEX

were

Also

design

the

Apex-16

use and

at

program.

made

considered

the

final

operating over

the

were

the

was

made

resolve

airfoil

the

geometry,

on

value

achievable

to be a strong since any

definition).

pullout

constraint

airfoil

pullout,

by the Apex-16

in level

on the flight,

has little

A workable

maneuver

pullout

then

sort

data

of lift

capability

approach

acquire

(or any

maneuver.

some

or no excess-hft

aiternative

but then

airfoil

which

in windup

was turns

CL.

Selection

Several

for the

Limited

B shows

is to be acquired

is to use wing lift to achieve

to achieve

1.4

if data

aircraft

It is in-

polars.

M2CL

was found

that

would

at its ceiling

1.3

matter)

concluded

Appendix

vehicle.

behavior.

[1] to fine-tune

constraints

parameter

test

studies

of interest.

off-design

performance

of airfoil ceihng

augmentation

LINDOP

objective

extensive

ranges and

requirements.

computed

Fairly

number

APEX

for lighweight

research

airfoil,

moment,

driver

for the

required

primary

this

Reynolds

conflicting

maximum

It was

is the

pitching

Study

airfoil

which

and

specifically

of airfoils

of designing

coordinates,

The

designed

to be representative

extreme

The

was

of tail airfoils

airfoils

for the

at low Reynolds and

2410

Examination

airfoils

of wing

tail

were

examined.

numbers, (inverted)

and

The

good

primary

tolerance

were identified

goal

to flap

as good

was

pre-

deflections.

candidates.

twist

A number

of issues

related

to wing

twist

obtaining

a uniform

local

cL across

the

were test

examined. section,

These

obtaining

included: a high

simplicity, overall

CLm,,_

for the

pullout,

avoiding

tip

In the

end

computationally. compromise

between

wing

--

halves

1.5

Test

It was

decided

pressure

stall.

all the

that

taps,

wake

the

complexity. the

The

A design

design

1.6

guide

are

wind

configuration, related a crucial program. integrating

tunnel

APEX

aspect The the of the

for the

tests,

of designing

Journal

a reasonable mold

was

for both

on Aurora's

high-altitude

due

with varying degrees for use on APEX. the

rakes

was

B and

C.

wakes

also

to weight

spanwise

of Aircraft

The

Theseus

aircraft,

results

of

unifor-

anticipated

prepared.

at test

The

layouts

tests airfoil/heat-exchanger

aircraft.

of heat

[2]. This

and

of compactness.

Although

exchangers

and

hence

not

has been

is relevant

have paper

already is attached

appeared

directly

identified

as

to the ERAST

studies and tunnel tests have proven the with the wing airfoil to achieve surprisingly

numbers.

gauges.

measurement

to verify

for an integrated

the aerodynamics

of surface

skin-friction

rejected

rakes

to capture

performed

consist

rake for accurate

integrating

integrating

would and

was

fixed wake

as Appendices

computational heat exchanger

examined

to verify spanwise uniformity, but data bandwidth available. Using a

traverse

specifically

is currently

at low Reynolds

'96 issue

desirable limited

multiple

designed

test

was

use of one

section

airfoil/heat-exchanger

which

to the

deemed of the

and

attached

the

wing

were

layout

test

layouts were designed, by Dryden personnel

guide

Integrated

A modest

levels

was

flat

microphones,

to use a single

defect,

rake

for the

on a mechanical

test section was selected

wake

altitudes. and

mounted

momentum

mity. Several One of these

allowed

and

surface-mounted

It was decided

wake

and

options

saving.

instrumentation

rakes,

washout

a simple

instrumentation

wake

rake

and

that

requirements, cost

Using multiple wake rakes was was found to be too demanding single

washin

it was decided

a significant

section

Both

validity of low drag

in the

as Appendix

Jan-Feb D.

References [1] M. Drela. 93-0969, [2] M. Drela. Aircraft,

Design

and optimization

method

for multi-element

airfoils.

AIAA

Paper

Feb 1993. Aerodynamics 33(2),

Mar-Apt

of heat 1996.

exchangers

for high-altitude

aircraft.

Journal

of

6 in

5

4

0.3 in. I

m

2

m

m

m

airfoil baseline

-1 m

m

m

-2

-3

APEX Drag Full size Mark Drela 12 Dec 95

Rake Layout

-

5

in

4

3 m

2 m

m

4.8 in

m

airfoil

baseline

m

-1 m

-2

APEX Integrating Full Size Mark Drela 19 Jan 96

Rake Layout

support

sting

°°°' o.-° °o

°°°°°°.o°°°'+°°°°°

o°o°°°°

. ........

Stanton • _.•

tubes

m

integrating

rake

°° °o °°°-°"

°°°°°+.°

o°°°°.°°°°°°'°°*°°°°°"

°°.°°'°°

,:;_'o

Microphones "*_.

support

sting

°

• •.

'O°oooo+ Ooo_+,. "..

0

wake rake rake statics °°° °°

°°°.°°.+o°.°,°°°

°°°°°°°°'

........ "Pressure pl)rts

APEX

Instrumentation

Layout

(proposed) Mark Drela 7 Feb 96

support

sting

Stanlontubes ,

support

sting

integrating

.., ..,.•

rake

Microphones 0

support • O00eO00000

•

•

sting (lightweight)

_

wake rake rake statics °.o"

Pressure

ports

support

sting

1,1,,I,,,,1''1

APEX Instrumentation (proposed)

Layout Mark Drela 9 Feb 96

II

Stantontubes support

sting

integrating

rake

"'Y"_'-L • Microphones support °°@°eOo°@°@

•

sting (lightweight)

°

m

wake rake rake statics

.°° °,

°°°°o°°

oo•o**

•

•

•

•

•

°°o°

•

•

°oo_o.°°'°'_°°°°°°°"'°°°

*oo*•oo_.*o*

Pressure

*

•

•

•

•

ports

support

APEX

sting

Instrumentation

Layout

III

(proposed) Mark Drela 9 Feb 96

Appendix

C:

Integrating

Rake

7

Design

Document

Integrating Mark

Rake

Drela, 10

MIT Dec

Design

Aero 95

& Astro

Ue

_.

¢

I

I (y)

I

rhi

I_ I [

L

I I I I

1 Ay

Z d_T____.___

Figure

1

Basic

and total

rake

in Figure

equal

to the

pressure

rake

layout

and

dimensions

Relations

An integrating as shown

1: Integrating

seen

consists

of an array

1. Assuming edge

value

by the

that

pe, the

of pitot

tubes

all feeding

static

pressure

across

the wake

velocity

profile

u(y)

=

½Pu2(y)

+

=

difference

non-uniform Poiseuille po - p,,

po(y)

_Pu2(Y)

will produce

flow in each where

entire

will produce

wake

reservoir, is constant

a y-dependent

pe

(1) 1

The

the

a common

tubes: po(y)

developed

into

Pr is the

+

a mass

tube,

this

mass

reservoir

Pooo

2

_pu_

flow rh_ in the

(2)

i'th

flow is proportional

pressure

tube.

Assuming

to the

driving

fullypressure

to be measured.

_r d4 rhl At steady-state, the

same

diameter

all the d and

tube length

mass 2, the

-

128 ve (Po, - P,.)

flows

must

pressure

add

(3)

up to zero,

differences

must

and add

if all the up to zero

tubes

have

as well.

N

Era, i----1

= 0

(4)

N

(po,- ;,) = 0

(5)

i=1

Substituting constant

for Poi in terms tube

spacing

of the

local

velocity

ui,

and

multiplying

by

the

presumed-

Ay, we get

N 1

2

- _pue+ po_- p,) ay = o

(6)

i=1 N

E (e_ - p_) Ay = 2(po_- p_)L

(7)

i=1

where N

L =

_Ay

NAy

(8)

i----1

is simply

the

the

height

of the

N-tube

The lefthand side summation momentum+mass defect

rake

as shown

in equation

in Figure

(7) is seen

pu_(o+ _') -

with

the

constant

tube

spacing

Ay,

For the most local-static Poo.-P_

accurate pressure

are

direct

2

Near-wake

Note

that

the

lems, from

estimate accurately

measurements

the

measured

calculation. the

shape

result

with

(9) (10)

is

_ 2(po_-p_)L

(11)

__

(12)

po_-p, L po o_ - P_

of 0 + g*, it is clearly to the

for

freestream no bias

total

best

to reference

pressure

the

Poo_, so that

reservoir

and

po_-p_

and

uncertainties.

Corrections rake

are to be used

since the

transducers

integrating

measurements

0+_*

measurement

integration

pu_)Ay,

the final

p_(0+_*) or

to be a midpoint-rule

f(pu_ - pu2(y))dy _(pu_-

so that

1.

sum

If the

not

give

minimum

the

0 + g* can simply H = 5*/0 velocity

Umin

momentum

or validate

goal is absolute

parameter

if only the

does

to support

drag

be compared

drag

measurement,

to deduce in the

=

min

the

wake

(_ee)

thickness

calculations,

isolated

with then

in isolation. this

the

causes

If the few prob-

corresponding

it will be necessary

0. This

can be done

sum to fairly

is known. (13)

Measuringthis will typically require a separatetotal pressuretube to the

wake

Assuming

the

approximated

minimum

by the

velocity

Coles

is known,

cosine

a wake

velocity

sufficiently

close

1[

_ is the

wake

half-thickness.

5" =

profile

is then

quite

closely

profile

u(y) _ Um_n+ (1 -- Cmln)_ 1 - cos _ Ue where

placed

centerhne.

From

1- -

the

;

definitions

-5

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