DL767captain From United States of America, joined Mar 2007, 2539 posts, RR: 0 Posted (4 years 2 months 1 week 6 days 5 hours ago) and read 1708 times:
today at school there was an osprey flying very low over my school, I have never seen one in person and it was very cool and surprisingly quiet. I don't know if there are any based around here but does any one know where it was from or where it was going?
UH60FtRucker From , joined Dec 1969, posts, RR: Reply 1, posted (4 years 2 months 1 week 6 days 3 hours ago) and read 1681 times:
Quoting DL767captain (Thread starter): I don't know if there are any based around here but does any one know where it was from or where it was going?
Umm, no offense, but how long have you been living in Solana Beach?
Ever heard of Miramar Marine Corps Air Station? Or the San Diego Naval Base? Two areas crawling with Marines and Sailors. In fact, the southern California region may be home to the most stateside Marines, compared to any other major USMC posting.
But anyway, yeah they're pretty cool. If you ever get to go in one, they're a lot smaller in person, though. One of the reasons it is more quiet than some helicopters is the lack of a tail rotor. On a helicopter that tail rotor is rotating much faster than the main blades, sometimes 4x as many rotations. The tail rotor creates a great deal of noise.
ShyFlyer From , joined Dec 1969, posts, RR: Reply 2, posted (4 years 2 months 1 week 6 days 2 hours ago) and read 1660 times:
They can also be pretty loud too. They frequently train at an airport near my home and they'll drown out the TV when they are overhead. From my own observations, the amount of noise generated is related to the angle of the prop-rotors. With the rotors down, they are super quiet and they literally sneak up on you. With the prop-rotors up, they rattle the windows and any loose dental work. I love it.
Tugger From United States of America, joined Apr 2006, 3557 posts, RR: 4 Reply 3, posted (4 years 2 months 1 week 6 days 1 hour ago) and read 1655 times:
Quoting DL767captain (Thread starter): I don't know if there are any based around here but does any one know where it was from or where it was going?
Go south young man, I watch them many days doing practice maneuvers into Miramar. They are pretty cool. The surprising thing is how short they look. From a distance they look so distinctive because they fly like an airplane but they just look short like a helicopter.
Tug
everything I have learned I have learned by mistake
JakeOrion From United States of America, joined Oct 2005, 1226 posts, RR: 2 Reply 4, posted (4 years 2 months 1 week 5 days 17 hours ago) and read 1574 times:
Quoting DL767captain (Thread starter): I don't know if there are any based around here but does any one know where it was from or where it was going?
Dragon6172 From United States of America, joined Jul 2007, 1142 posts, RR: 0 Reply 5, posted (4 years 2 months 1 week 5 days 11 hours ago) and read 1511 times:
Quoting JakeOrion (Reply 4): Yes and no. On the ground, they are loud as hell, but in the air, they are fairly quiet.
Quoting ShyFlyer (Reply 2): With the rotors down, they are super quiet and they literally sneak up on you. With the prop-rotors up, they rattle the windows and any loose dental work.
As I recall the prop rotor RPM while in airplane mode is only 81% of helicopter mode. That slows the tip speed of the blades down and is one of the big reasons why it is more quiet in airplane mode.
Quoting UH60FtRucker (Reply 1): One of the reasons it is more quiet than some helicopters is the lack of a tail rotor.
True in the sense that you dont have that high speed tail rotor making noise, but a H-46 doesn't have a tail rotor and they are about as loud as any conventional helo. In fact I would say the H-60 is much quieter than a H-46.
HaveBlue From United States of America, joined Jan 2004, 1981 posts, RR: 1 Reply 6, posted (4 years 2 months 1 week 5 days 10 hours ago) and read 1488 times:
Quoting Dragon6172 (Reply 5): True in the sense that you dont have that high speed tail rotor making noise, but a H-46 doesn't have a tail rotor and they are about as loud as any conventional helo. In fact I would say the H-60 is much quieter than a H-46.
And the Chinook is very loud, like a Huey in stereo.
I first saw the Osprey in the mid 90's when I was working near Eglin AFB. I was going down either SR85 or 123, been a while, but anyways was on the road on the north side of the base when I saw him coming in with the engines in transition for landing. Always having a camera loaded and ready in the backseat I managed to get a picture of it, shitty as it may be. Also saw one flying overhead at altitude while at the USAF Armarment museum there, standing by the SR-71 heard it and looked up. Another shitty picture heh. The cool thing about it was that at that time, very few people had seen it and it definitely wasn't making public appearances yet. I don't recall what it sounded like.
UH60FtRucker From , joined Dec 1969, posts, RR: Reply 7, posted (4 years 2 months 1 week 5 days 6 hours ago) and read 1429 times:
Quoting Dragon6172 (Reply 5):
True in the sense that you dont have that high speed tail rotor making noise, but a H-46 doesn't have a tail rotor and they are about as loud as any conventional helo. In fact I would say the H-60 is much quieter than a H-46.
I've noticed that the H-46 creates an extremely great deal of noise from it's engines. When ever I hear those things landing, that is what I hear the most. I always mean to ask the pilots when I am around them, but I keep forgetting, I'd like to know the typical engine RPM. I'm willing to be it's very high.
Quoting HaveBlue (Reply 6): And the Chinook is very loud, like a Huey in stereo.
Actually, on the decibel scale, it's not.
People will sometimes assume that larger aircraft = louder noise profile... which is completely baseless. The loudest aircraft in the US Army is actually the UH-60, much in part due to the tail rotor. Followed by the AH-64, then the CH-47, the UH-70, and finally the OH-58
What gives people the impression that the CH-47 is "louder" is the human interpretation of "thickness noise". The mind interprets this noise as being loudest, due to the fullness of the sound. However, the higher frequency of the noises produced by the tail rotor and blade vortexes are louder when measuring decibels.
Dragon6172 From United States of America, joined Jul 2007, 1142 posts, RR: 0 Reply 8, posted (4 years 2 months 1 week 4 days 16 hours ago) and read 1366 times:
Quoting UH60FtRucker (Reply 7): I've noticed that the H-46 creates an extremely great deal of noise from it's engines. When ever I hear those things landing, that is what I hear the most. I always mean to ask the pilots when I am around them, but I keep forgetting, I'd like to know the typical engine RPM. I'm willing to be it's very high.
As I recall the gas generator operated somewhere in the area of 26,000 RPM, and the power turbine was somewhere around 19,500. A lot of background noise you hear comes from the transmissions, believe me I have been in them when the engines shut down and it does not change the noise level much.
Quoting UH60FtRucker (Reply 7): What gives people the impression that the CH-47 is "louder" is the human interpretation of "thickness noise". The mind interprets this noise as being loudest, due to the fullness of the sound. However, the higher frequency of the noises produced by the tail rotor and blade vortexes are louder when measuring decibels.
I interpret how loud a helicopter is by how far away I can hear it (because honestly that is what matters when you are looking for that element of "surprise" during an insertion).
Sponsor Message: 
From United States of America, joined Mar 2007, 2539 posts, 
I love it.
Sponsor Message: 
Printer friendly format
