My first thought was that a helicopter's engine(s) probably don't suffer from FOD because the main rotor blade's downwash of air likely blows any foreign objects away from the chopper .... they've done a good job of blowing a lot of dirt into my face in the past.
However, the engines need to breath in air somehow, so I'm wondering .......
Are helicopters with turbine engines protected from FOD?
If they are, what method of protection is used?
Are there screens that cover the air intakes? (is that a good idea?)
Do turbine helicopters have inertia separators like many turboprops with reverse flow engines do? Can a inertia separator even help during a vertical takeoff & landing? (due to the low to zero forward speed).
I'm sure most turbine helicopters land on clean areas like airport ramps & Heli Pads, but for the ones that need to occasionally land in fields of dirt & grass for the purpose of a Medivac flight, etc .... do they need FOD protection?
777WT From United States of America, joined Jan 2005, 874 posts, RR: 1 Reply 1, posted (7 years 7 months 4 weeks 1 day 12 hours ago) and read 5127 times:
Quoting Mr Spaceman (Thread starter): Do turbine helicopters have inertia separators like many turboprops with reverse flow engines do? Can a inertia separator even help during a vertical takeoff & landing? (due to the low to zero forward speed).
Yes they do have inertia seperators. It does not matter what speed it's traveling at. It's the speed and velocity of the airflow going into the intake. There is also a screen filter in it too.
Some helicopters don't have them and it's just basically a cone screen like covering the intake.
Mr Spaceman From Canada, joined Mar 2001, 2780 posts, RR: 15 Reply 2, posted (7 years 7 months 4 weeks 1 day 5 hours ago) and read 5071 times:
Thank You, for you answer.
OK, so the engine's intake compressors suck air into the engine compartment fast enough that a foreign object with enough mass would pass through the inertia seperator vent and exit the intake compartment ...... regardless of the helicopter's speed through the air.
I just assumed that ram air speed for the intake flow had something to do with it because I was thinking about fast moving turboprops. I shouldn't assume.
I wonder how often medivac helicopters that land in fields need to have their intake screens checked & cleaned of leaves & grass, etc, if they're getting clogged up?
PS, do Bell 427 helicopters in particular have inertia seperators? I'm just curious because I really like those choppers.
Mr Spaceman From Canada, joined Mar 2001, 2780 posts, RR: 15 Reply 4, posted (7 years 7 months 4 weeks 1 day 3 hours ago) and read 5058 times:
Thanks for your explanation. I'm not sure what I was wondering about when I asked how often the intake screens are checked. It only makes sense that the intakes would be inspected prior to & after each flight ..... regardless of the flight's mission.