Wie funktioniert der Triebwerkstart einer F/A-18?

[Alonzo]

Hoi zäme

 

Frage: Wie geht eigentlich der Triebwerkstart einer genau F/A-18 vor sich?

 

Bei der F-16 gibt es dafür den JFS (Jet Fuel Starter, arbeitet mit Druckluft), der ganze Startvorgang ist unter http://www.f-16.net/f-16_forum_viewtopic-t-200-start-0.html sehr anschaulich erklärt. Für die F/A-18 konnte ich jedoch nirgends eine vergleichbare Erklärung finden - wie funktioniert es da? Braucht es externe Power/Luft o.ä., oder kann eine F/A-18 ihr Triebwerk autonom starten? Und woher kommt das charakteristische Tuten beim Triebwerkstart?

 

Besten Dank für klärende Infos!

[Boelkstoff]

Soweit ich weiss,(und im Militär gesehen habe), haben die eine Hilfsturbine,welche elektrisch gestartet wird. Damit werden die Triebwerke dann "angepustet". Der Ton den du meinst stammt angeblich von der Luft, die durch Bypässe gedrückt wird. Genauer kann ich es nicht sagen, war nicht bei den Hornets, durfte "nur" an den Tigerlis rumschrauben:rolleyes:

 

Gruss Marcel

[D-EBIP]

Die Hornet hat eine eigene APU (Auxiliary Power Unit) knapp hinter dem Hauptfahrwerksschacht, und kann damit die Triebwerke auch autonom starten. Die Ein- und Auslässe der APU sind an der Rumpfunterseite angebracht:

 

Bild vom APU-Lufteinlass, Blick in Flugrichtung:

http://personal.eunet.fi/pp/vmhalme/hornet_finnaf/073hornet_swissaf.jpg

 

APU-Luftauslass oben links, Blick in Flugrichtung:

http://personal.eunet.fi/pp/vmhalme/hornet_finnaf/074hornet_swissaf.jpg

 

Bildquelle: http://personal.eunet.fi/pp/vmhalme/hornet_finnaf/index.html

 

 

Mit der kompletten Startup-Sequenz kann ich leider nicht dienen, sorry.

[Young Pilot]

Auszug aus dem Superbug FA18 Manual:

 

8.0.2.1 APU START

A self-contained (battery/APU) start is the primary method for starting the

engines. The aircraft also has provisions for starting on opposite engine bleed

air (crossbleed) for circumstances when that may be appropriate (e.g., alert

launch, low battery, maintenance, engine restart after APU shutdown, etc.).

With an external power start, all electrical systems are operative. With a

battery start, power is available to operate the APU and engine fire warning

systems, the caution lights panel and the EFD backup display.

The right engine is normally started first in order to provide normal hydraulics

to the brakes. During first engine battery start, the EFD RPM indication

typically jumps from 0 to 5 or 10%, and light-off is indicated by TEMP rising

from a minimum reported value of approximately 190°C. When the

corresponding generator comes online (approximately 60%N2 rpm), the

engine crank switch returns to OFF. After both generators are online, the APU

will run for 1 minute and then shut down automatically.

 

Engine start checks -

[ ] PARK BRK handle FULLY SET

[ ] BATT switch ON

[ ] Battery gauge CHECK

 

Nominal voltage for a "good" battery should be 23 to 24 vdc. Minimum

battery voltage is that which provides a successful engine start (i.e., APU

remains online and the EFD remains powered to provide indications of RPM

and TEMP). EFD blanking and/or uncommanded APU shutdown should be

anticipated with a battery voltage at or below approximately 18 vdc. If a weak

battery results in an unsuccessful engine start attempt, the battery should be

charged or replaced prior to takeoff, since the battery provides the last source

of electrical redundancy for the FCCs.

 

With external electrical power -

[ ] EXT PWR switch RESET

[ ] GND PWR switches 1, 2, 3 and 4 B ON

[ ] L® DDI, HUD, and MPCD knobs ON

VRS F/A-18E Superbug Section VIII: Checklists

267 Checklists

[ ] COMM 1 and 2 knobs ON

[ ] LT TEST switch TEST

[ ] DDI/MPCD/UFCD ENTER DESIRED WPTS

All starts - ON

[ ] FIRE test switch TEST A

[ ] FIRE test switch NORM

[ ] FIRE test switch TEST B

 

During a successful FIRE warning test ALL of the following lights should

illuminate in each TEST position: both FIRE lights, the APU FIRE light, and both

L and R BLEED warning lights. Additionally, the following voice aural warnings

should be heard in order: "Engine fire left, engine fire right, APU fire, bleed air

left, bleed air right" (each repeated twice).

[ ] APU ACC caution light VERIFY OFF

[ ] APU switch ON (within 30 seconds)

[ ] RGEN switch ON

[ ] BLEED AIR knob R-OFF/OFF

[ ] Right throttle IDLE

[ ] ENG CRANK switch R (10% N2 minimum.)

Oil pressure should be a minimum of 10 psi within 30 seconds. Maximum

transient EGT during start is 871°C.

[ ] Battery gauge VERIFY 28 vdc

[ ] L® DDI, HUD and MPCD knobs ON

EFD - CHECK (ground idle) -

[ ] RPM 61% min

[ ] TEMP 250-500c

[ ] FF 600-900 pph

[ ] OIL 35-90 psi (warm oil)

[ ] NOZ 77% to 83%

If external power start -

External electrical power DISCONNECT

[ ] BLEED AIR knob NORM

[ ] LT TEST switch TEST

VRS F/A-18E Superbug Section VIII: Checklists

268 Checklists

[ ] ENG CRANK switch L

[ ] Left throttle IDLE (10% N2 minimum.)

[ ] ENG CRANK switch CHECK OFF (prior to lightoff)

[ ] EFD CHECK

 

8.0.2.2 CROSSBLEED START

[ ] APU switch OFF

[ ] BLEED AIR knob NORM

[ ] ENG CRANK switch L®

[ ] Operating engine throttle 80% N2

[ ] Starting engine throttle IDLE (10% N2 minimum.)

[ ] ENG CRANK switch CHECK OFF

[ ] EFD CHECK

 

Happy New Year,

 

Roman