2009-09-10.pdf

4 Linemen & A&Ps sPeAk 4 Over the mOOn 4 FLy tO AcAdiA nAtiOnAL PArk sePtember/OctOber 2009

The Magazine for Adventure Flying

Air rAce sPeciAL

Pilots, Pylons & Power!

Champion Racer puts you

in the pilot’s seat!

$ 7.95 US

WOrking beAvers in Fiji

» Better

engineS

through

raCing

Page 20

FrOm the AirWAy tO the FAirWAy

Mooney aCClaiM to tPC SCottSdale

Working Beavers

in Fiji

A Beaver gently banks overhead, engine romantically rumbling.

Never in our wildest dreams did we imagine to ind a North

American icon in the South Paciic.

Photo by John Parker

PILOTMAG J u ly / A u g u s t 2 0 0 9

SEPTEMBER/OCTOBER 2009

The MAGAZINE AND ONLINE Guide for Adventure Flying

FeaTUres

ConTenTs

www.pilotmag.com

Like a

MoTh

To a

FLaMe

On any given Sunday

throughout the country,

an audience of millions

is captivated by the

“kisses” of NASCAR or

a running-back breaking

through the defensive

line. But why aren’t more

people watching air

racing?

5 CONTRIBUTORS

7 PUBLISHER’S NOTE

DeParTMenTs

9 ECOSYSTEM

13 PRODUCT REVIEW

The almighTy TUg

18 FUTURE FLIGHT

20 ENGINE MAINTENANCE

how To keep engines prime for racing

24 UFO

windersTarT in german

28 NTSB INSIDER

65 over The Moon

Once in a blue moon, we are reminded that mere

mortals learned to take aim at the sky and ling

a small metal capsule at the heavens. The

moon’s inspiration still exists.

aircrafT salvage

31 AERODYNAMICS

34 LINEMEN, A&Ps, AIs

41 SITE PICTURE

74 TRAVEL

fly To acadia naTional park

96 NAHI

The heriTage Trophy aT reno

98 ZENITH AIRCRAFT

a life BeTTer lived

104 FINAL APPROACH

74 aCaDia

naTionaL Park

Welcoming more than two million

travelers a year, Acadia covers

more than 40,000 acres. The park

encompasses nearly half of Mount

Desert Island, a scattering of smaller

islands, and the Schoodic Peninsula.

Take a light to Bar Harbor–Hancock

Airport for some fresh lobster.

76 a PerFeCT Drive.

a PerFeCT Day.

On the white tee of the famous 15th hole of

the Tournament Players Club Stadium Course

in Scottsdale, Arizona, looking down the long

verdant fairway, straightening my green plaid

knickers and Polo a la Payne Stewart, I swear

that the towering prickly Saguaro cactus is

lipping me the bird as I try to keep my rusty

game together.

About the Cover: Favored to win the

Unlimited Class at this year’s 2009 National

Championship Air Races in Reno, the P-51D

Mustang, Strega, and Bill “Tiger” Destefani

prepare for a heated battle in the desert.

Photo by Tyson Rininger

s E P t E M B E R / O C t O B E R 2 0 0 9 PILOTMAG.cOM

A I R C R A F T E N G I N E S

B e t t e r

EnginEs

t h r o u g h

Racing

By Steven W. Ells

Air racing is the proving ground for air-cooled aircraft innovations. Consider this:

In 1947 the Professional Racing Pilots Association formed rules for “midget” racing. The goal was

to reduce the cost of air racing. Goodyear Tire and Rubber provided sponsorship and just seven

months later 13 airplanes crossed the starting line in Cleveland for the inaugural race, which was

won by pilot William Brennand in “Buster,” a Steve Wittman design. The winning speed was

165.9 mph.

Initially midget racing engines were limited to 190 cubic inches. Continental’s C- 85 engine it

the bill but after a couple of decades serviceable components-especially crankshafts—be-

came as scarce as an NDB approach. In mid-1968 the F1 ruling body OK’ed the use of the

affordable and plentiful Teledyne Continental Motors (TCM) O-200 engine. This engine is

best known for powering Cessna’s C-150 trainer. It’s rated for 100 horsepower at 2750

rpm. At about that time the class was oficially recognized and renamed Formula 1.

F1 rules spell out wing size, minimum aircraft weight, minimum fuel quantity and

other parameters but in spite of these constants the fact remains—in

1996 the qualifying speeds at the Reno F1 race were over 100 mph

faster than the speed of the top qualiier in 1947 on an engine that

has only 5 percent more displacement.

Improvements in airframe construction methodologies and

materials have made a huge difference in reducing drag but

the following sentence sums up the gist of F1 engine

improvements:

“Since an aircraft engine is nothing more than an air

pump the eficiency at which an engine draws in and

expels air determines its overall performance”--John Schwaner,

“Sky Ranch Engineering Manual”

Volumetric eficiency is the ratio between the theoretical

amount of air drawn into the engine and the actual amount

of air drawn in. A higher ratio yields more power.

PILOTMAG.cOM s e p t e m b e r / o c t o b e r 2 0 0 9

A I R C R A F T E N G I N E S

F1 RaceRs

Formula 1 engines can be modiied, but not as much as might be ex-

pected. F1 rules that aim to keep F1 racing affordable require that the

weights and sizes of major power components must conform to limits

and that compression ratios can’t be greater than the stock number of

7.0:1. Out-of-the-pump avgas must be burned. So how do they get so

much power out of an O-200? By increasing volumetric eficiency and

installing specially-built propellers which free the engines to spin up to

between 3800 and 4400 revolutions per minute (rpm).

O-200 manufacturer TCM publishes 3300 rpm as the over-speed limita-

tion for the O-200. Spin an O-200 installed on a certiied airplane faster

than 3300 rpm and you’re advised to remove, tear down and inspect

the engine and accessories for damage. How do F1 engine builders

keep their engines together? It all boils down to the expertise of the

engine builders. According to one of the builders the task of lying in

close proximity to other racers at speeds of to 280 mph automatically

relegates engine management chores to the basics. Push the throttle

forward as far as it will go and lean to a best power mixture (70 to 80

degrees rich of peak) and try to keep up.

Increases in volumetric eficiency cause dramatic increases in engine

output as fuel lows increase to 14 to 15 gallons per hour—roughly

twice the normal fuel low of a stock

O-200. More fuel also causes more

heat--cylinder head temperatures often

top 500 ° F.

Are special parts used? Yes, to some degree,

but it’s not a free-for-all. F1 racers must use TCM

factory or oficially approved parts but they may

change “any it, clearance, or oil lube hole to compensate

for increased heat and rpm.” Higher rpms are a function of

higher volumetric eficiencies.

ImpRovIng volumetRIc eFFIcIency

Port polishing and low porting is the practice of smoothing the inner

surfaces and ine-tuning the it between induction system components

to lessen airlow discontinuities. According to Schwaner the goal is to

reduce the “pressure differential that exists between the intake mani-

fold and the cylinder during the intake stroke.”

Other processes used to improve eficiency are increasing intake valve

size and matching lifters and camshaft lobe proiles so that all cylinders

breathe evenly and produce the same power. Valve timing is sometimes

advanced to compensate for the reduced valve-open periods due to

higher rpms, and intake valve seat angles are ine-tuned to further re-

duce restrictions to air low. A ive-angle valve seat cut—instead of the

three-angle cut common on FAA certiied engines--increases eficiency

by lessening the angles of airlow change. Visualize the low of water

down a rock-strewn creek bed and compare that to the same low

down a smooth gutter. More water can low faster down the smooth

gutter. It’s that simple.

With every tune, there’s always a back beat. As RPM is increased

volumetric eficiency decreases simply because the time window for

the fuel/air charge shrinks. Research shows that the stoke time at 2400

RPM is 12 hundredths (0.012) of a second. At 3600 RPM the interval

shrinks to 8 thousandths (0.008) of a second—one tenth of the time.

Counter that engine operating whipsaw with the fact that increases in

horsepower and RPM increase dynamic forces on mechanical compo-

nents. Not only must the components be able to withstand higher loads

but they must be lighter in weight to successfully compete. What steps

do builders take to insure durability?

FIt and FInIsh

“You can’t be clean enough or careful enough,” says Monty Barrett

Sr. of Barrett Performance Engines (BPE) when talking about building

engines. “It’s not quite a clean room but there’s nothing in there except

the tools—there’s no eating or drinking.”

Ken Tunnel of Lycon Aircraft Engines says his shop does “extreme

s e p t e m b e r / o c t o b e r 2 0 0 9 PILOTMAG.cOM 21

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