Ivo21
Topic Author
Posts: 25
Joined: Sun Jan 13, 2002 8:52 pm

HMU/FADEC

Wed Jun 05, 2002 9:19 pm

I have a question,

On an HMU of any high bypass engine, the medium used to transmit any form of adjusting of the vanes and valves is done by pressurised fuel from the HMU.
But when fuel is pressurised at such an extend, it there a safety built in to protect the pressurised fuel lines from air/oxygen entering the fuel pressurised system. Because if air did get in, you would have not only an engine fire, but a wing fire I think.

What do you think??

Ivo 21
 
NKP S2
Posts: 1665
Joined: Mon Dec 20, 1999 3:16 am

RE: HMU/FADEC

Wed Jun 05, 2002 11:19 pm

It's a closed system...and in any event, "air" is just that: Air, a 21/78 O2/N2 mix...not 100% oxygen. The largest concern however would be a leak, in either the fuel lines, or the dynamic/static seals in a component; This is why line couplings for high pressure fuel running in the core (hot ) area are shrouded and provided with their own overboard drain system. This is also the case for the VBV and VSV actuators: They're constructed in such a way that a blown seal would be directed to a drain line or lines, and run out of the drain mast instead of spraying all over the hot core. Fuel pumps, and HMU's ( or MEC's, or FFG's, as the case applies ) etc are provided with drains as well if the shaft or other seals fail or "weep" fuel.

Who is online

Users browsing this forum: badgervor, Classa64, sharles, ucdtim17 and 1 guest

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos