User Panel
User Panel
User Panel
|
Posted: 4/11/2014 6:05:28 AM EDT
[#1]
Easily one of my favorite badass scout helicopters.
|
|
|
|
Posted: 4/11/2014 3:04:18 PM EDT
[#2]
What is the pitch range of something like that? What is the negative pitch capabilities for a regular bird, I assume would only be used for autos?
|
|
|
|
Posted: 4/11/2014 11:40:50 PM EDT
[#3]
You mean pitch on the blades? Helicopter blades don't go negative pitch.
Minimum thrust is generally a couple % of the max aircraft weight and max thrust varies a lot, from 80% of the gross weight up to maybe 200-300% depending on what it's designed for and how much load it's carrying. |
|
|
|
Posted: 4/11/2014 11:46:35 PM EDT
[#4]
The lynx is a bad bird! World record holder as fastest helicopter from what I recall. These dudes are nuts though! |
|
|
|
Posted: 4/11/2014 11:52:05 PM EDT
[#5]
Quote HistoryQuoted:
What is the pitch range of something like that? What is the negative pitch capabilities for a regular bird, I assume would only be used for autos? The pitch change links are adjusted for a certain rotor RPM range in an autorotation by the MTP. Its based on DA and weight. As for the angle of incidence to be negative, well, I have heard of some Navies setting the aircraft up so they would "stick" to the deck if needed. For the rest of us its just basically flat pitch. In the Kiowa we were prohibited from pulling negative Gs. The Apache can pull some. It puts a lot of stress on already highly dynamic components. |
|
|
|
Posted: 4/12/2014 3:09:36 AM EDT
[#6]
As far as stress on the aircraft, the attitude of a helicopter matters very little. Upside down, right side up, whatever. The biggest factor by far is the aggressiveness of a maneuver and the resulting pitch/roll/yaw rates of the aircraft.
Virtually all helicopters with more than 2 blades can easily do any basic aerobatic maneuvers. There's no practical need for it and helicopters fly close to the ground, so minor errors in such maneuvers have bad outcomes. So aerobatics are rarely done in helicopters. 2 bladed helicopters must maintain significantly positive G at all times. Given the low airspeeds and draggy nature of helicopters, this makes even 1 g aerobatic maneuvers too difficult and risky to attempt. |
|
|
|
Posted: 4/12/2014 3:18:47 AM EDT
[#7]
Mast bumping and cutting your tailboom off are fun things you can do in a helicopter if you exceed design limitations.
|
|
|
|
Posted: 4/12/2014 3:44:03 AM EDT
[#8]
FRANK MURPHY: "MEH...any tub of $h1t can do that..."
Seriously, what an amazing bird, and amazing flying 
|
|
|
|
Posted: 4/12/2014 12:23:06 PM EDT
[#9]
Quote HistoryQuoted: The pitch change links are adjusted for a certain rotor RPM range in an autorotation by the MTP. Its based on DA and weight. As for the angle of incidence to be negative, well, I have heard of some Navies setting the aircraft up so they would "stick" to the deck if needed. For the rest of us its just basically flat pitch. In the Kiowa we were prohibited from pulling negative Gs. The Apache can pull some. It puts a lot of stress on already highly dynamic components. Quote HistoryQuoted: Quoted: What is the pitch range of something like that? What is the negative pitch capabilities for a regular bird, I assume would only be used for autos? The pitch change links are adjusted for a certain rotor RPM range in an autorotation by the MTP. Its based on DA and weight. As for the angle of incidence to be negative, well, I have heard of some Navies setting the aircraft up so they would "stick" to the deck if needed. For the rest of us its just basically flat pitch. In the Kiowa we were prohibited from pulling negative Gs. The Apache can pull some. It puts a lot of stress on already highly dynamic components. So typically an auto rotation would be 0 pitch to start? |
|
|
|
Posted: 4/12/2014 1:38:49 PM EDT
[#10]
Define 0 pitch.
All helicopter blades are twisted so an entire blade is never at the same pitch. The minimum pitch of a helicopter rotor will always generate some thrust in order to be capable of autorotating. When autorotating you constantly change the collective pitch to keep the rotor speed where you want it. |
|
|
|
Posted: 4/12/2014 4:06:43 PM EDT
[#11]
Quote HistoryQuoted: Define 0 pitch. All helicopter blades are twisted so an entire blade is never at the same pitch. The minimum pitch of a helicopter rotor will always generate some thrust in order to be capable of autorotating. When autorotating you constantly change the collective pitch to keep the rotor speed where you want it. Zero pitch would be zero lift, provided we are talking a symmetrical blade. |
|
|
|
Posted: 4/12/2014 4:59:08 PM EDT
[#12]
No symmetrical blades on any modern helicopter. And all blades are twisted, so you can't have 0 lift everywhere on a blade.
|
|
|
|
Posted: 4/15/2014 3:57:04 AM EDT
[#13]
Here are some pitch ranges for some modern helicopters.
R22 Beta [+1.5 +14.5]; 300C [+3 +15]; Bell 412 [0 +16]; MD500E [0 +14.3]; CH-53E [-1.4 +19.6]; BK117 [-1.8 +13.3]; BO105CB [-0.2 +15]; UH-60A [+9.9 +25.9] |
|
|
|
Posted: 4/15/2014 12:12:41 PM EDT
[#14]
Quote HistoryQuoted:
Here are some pitch ranges for some modern helicopters. You need to clarify your verbiage. "Pitch range" is ambiguous at best. Throwing numbers like that around only muddies the water, they're meaningless without context. If you mean the angular range of how much a blade can physically change AOA, then what is 0 and where is the measurement taken? What position are the controls in when the measurements are taken? Where in the rotation axis are the blades? All those things change the numbers. You're basically saying a 300lb guy is better at football than a 250lb guy. Is that true? Obviously the answer is "it depends". |
|
|
|
Posted: 4/15/2014 4:14:56 PM EDT
[#15]
Quote HistoryQuoted: Here are some pitch ranges for some modern helicopters. R22 Beta [+1.5 +14.5]; 300C [+3 +15]; Bell 412 [0 +16]; MD500E [0 +14.3]; CH-53E [-1.4 +19.6]; BK117 [-1.8 +13.3]; BO105CB [-0.2 +15]; UH-60A [+9.9 +25.9] Thanks for the answer. Wow, 26 degrees of pitch for the UH-60. I was just up close with a UH-60 rotor head today, sexy piece of engineering.  I watched a CH-53 land on a golf course next to my apartment about 6 years ago. It drew a lot of attention, that thing is a beast. |
|
|
|
Posted: 4/15/2014 5:48:31 PM EDT
[#16]
Quote HistoryQuoted:
Wow, 26 degrees of pitch for the UH-60 Sometimes I wonder why I even bother. |
|
|
|
Posted: 4/15/2014 5:55:25 PM EDT
[#17]
Quote HistoryQuoted: Sometimes I wonder why I even bother. Quote HistoryQuoted: Quoted: Wow, 26 degrees of pitch for the UH-60 Sometimes I wonder why I even bother.  |
|
|
|
Posted: 4/15/2014 7:40:55 PM EDT
[#18]
Quote HistoryQuoted:
You need to clarify your verbiage. "Pitch range" is ambiguous at best. Throwing numbers like that around only muddies the water, they're meaningless without context. If you mean the angular range of how much a blade can physically change AOA, then what is 0 and where is the measurement taken? What position are the controls in when the measurements are taken? Where in the rotation axis are the blades? All those things change the numbers. You're basically saying a 300lb guy is better at football than a 250lb guy. Is that true? Obviously the answer is "it depends". Quote HistoryQuoted:
Quoted:
Here are some pitch ranges for some modern helicopters. You need to clarify your verbiage. "Pitch range" is ambiguous at best. Throwing numbers like that around only muddies the water, they're meaningless without context. If you mean the angular range of how much a blade can physically change AOA, then what is 0 and where is the measurement taken? What position are the controls in when the measurements are taken? Where in the rotation axis are the blades? All those things change the numbers. You're basically saying a 300lb guy is better at football than a 250lb guy. Is that true? Obviously the answer is "it depends". You are exactly right. I just provided mechanical numbers with no context. But that is what the OP asked for This chart may help the OP. Helicopter aerodynamics aren't the most simple of things.
|
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
