Maximum fall speed of a helicopter with disabled rotors
Thread Starter
Join Date: Jun 2012
Location: Netherlands
Age: 42
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Maximum fall speed of a helicopter with disabled rotors
Hello,
Does somebody know the maximum falling speed of a heli like a bell222, with engine off and disabled rotors? If I have this variable I can calculate the air resistance for the heli flight simulator I'm making...
Regards,
Nathaniel
Does somebody know the maximum falling speed of a heli like a bell222, with engine off and disabled rotors? If I have this variable I can calculate the air resistance for the heli flight simulator I'm making...
Regards,
Nathaniel
Take a set of streamlined car keys and drop them......that would be pretty close I think!
The Vmax of a falling human body is about 120mph or 10560ft/min so a helicopter with rotors stopped will fall at around that speed assuming it falls from a height which allows it to reach terminal velocity.
HF
HF
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 429 Likes
on
226 Posts
120 mph for a human meat bomb, yes - but terminal velocity of a falling object varies with the individual item being dropped.
For example, Barnes Wallis designed a streamlined bomb that was designed to reach supersonic speed in free fall from 40,000 feet (it didn't because there was no suitable aircraft to lift it high enough to accelerate for long enough).
But even 120 mph with the rotors stopped will make the pilot's eyes water.
For example, Barnes Wallis designed a streamlined bomb that was designed to reach supersonic speed in free fall from 40,000 feet (it didn't because there was no suitable aircraft to lift it high enough to accelerate for long enough).
But even 120 mph with the rotors stopped will make the pilot's eyes water.
Would not most any velocity normally achieved in a rotors stopped free fall event be considered "terminal"?
Be kind to the guy - he is obviously not a pilot and English may not be his first language. I would guess his question is really referring to autorotation (disabled rotors = disengaged rotors = autorotating ??? - he did not say "Rotors stopped")
I don't have a figure for Bell 222 but would guess at around 2 500 feet per minute in a stabilised auto ??? Sure someone will give you a more accurate figure
I don't have a figure for Bell 222 but would guess at around 2 500 feet per minute in a stabilised auto ??? Sure someone will give you a more accurate figure
Last edited by farsouth; 25th Jun 2012 at 22:52.
That would make better sense than what most of us thought he meant. Someone with a 222 or 230 manual handy?
One test is worth 1000 expert opinions.
IFMU
IFMU
Join Date: Mar 2007
Location: London
Posts: 198
Likes: 0
Received 0 Likes
on
0 Posts
But even 120 mph with the rotors stopped will make the pilot's eyes water.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 429 Likes
on
226 Posts
One test is worth 1000 expert opinions.
Most Bell 206 comments i found doing a google search shows about an average 1800 Feet Per Minute Rate of Descent.
I would guess.....for the 222 it would be from about 1600-2500 fpm depending upon collective setting and main rotor RPM.
I would guess.....for the 222 it would be from about 1600-2500 fpm depending upon collective setting and main rotor RPM.
I don't think he/she is asking for rate of descent in autorotation. My guess is that the question refers to helicopter drag (air resistance), in particular the drag created by the airframe shape itself. I'm not sure if any of the helicopter manufacturers publish such data but in any case it would really depend on which way the airstream is hitting the fuselage.
His initial question....which we should interpret as being authoritative descent rate....and from that ....he can do his calculations.
Does somebody know the maximum falling speed of a heli like a bell222, with engine off and disabled rotors? If I have this variable I can calculate the air resistance for the heli flight simulator I'm making...
Awlrite......"a u t o r o t a t i v e".....down to one eye right now and sometimes I don't see what i actually typed....old age and Cataracts!
Last edited by SASless; 26th Jun 2012 at 22:28.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,576
Received 429 Likes
on
226 Posts
Those predictive text brains are not always so user friendly... 
Chief Bottle Washer
In the meantime you are talking to each other, as is so often the case with newbies who visit once in a blue moon and don't have the courtesy to return and acknowledge the advice they have sought
