Helicopter rudder pedals
Join Date: Nov 2004
Location: Cambridgeshire, UK
Posts: 1,334
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for all the info, SASless. I took the route of engineer since that is where i am best applied, but i like to understand the Chook handling quirks. I'm starting to gain insight as to just how vital SAS is on large helicopters.
Was there a tendancy to use cyclic to correct for front translation with yaw? I imagine converting to tandem the first thing to get used to is sitting so far ahead of the CofG. Likewise i imagine that it took some discipline not to correct the thrust everytime pitch attitude was changed, like lifting aft wheels off the ground. I imagine getting the feel of the machine took a little time.
Was there a tendancy to use cyclic to correct for front translation with yaw? I imagine converting to tandem the first thing to get used to is sitting so far ahead of the CofG. Likewise i imagine that it took some discipline not to correct the thrust everytime pitch attitude was changed, like lifting aft wheels off the ground. I imagine getting the feel of the machine took a little time.
An interesting situation in Tandem Rotor helicopters is when one head enters translational lift and the other does not....which frequently happens if a takeoff at max possible weight (MPW) is attempted. MPW being where you exhale to lighten the load while creeping off as smoothly you can for any roughness of control touch results in a settling back to earth.
As the forward head enters ETL....the tendency is for the nose to climb as the forward head is producing more lift than the aft head....an application of forward cyclic cures the pitch up problem but also decreases lift in the aft head...if your rate of acceleration is insufficent to get both heads flying in ETL....major problem.
A very common techique for acheiving MPW performance was to use Yaw pedals to swing the aft head into clean air and combine the sideways rotation of the airframe and the cleaner air to bring the aft head into ETL at the same time as the forward head. Timing was of the essence in that maneuver.
It is great fun to find yourself behind the power/altitude/speed/experience/idea curve with the Mr down from 230 rpm to 190 rpm, gennies dropped off line, and SAS kicked out due to loss of electrics....while holding the thrust level up under your armpit and trying to think up a sound explanation that will satisfy the Accident Review Board.
MPW by the way is the real ACL (Average combat load) for the aircraft as found in reality vice the SOP's.
We asked a lot of the old girls and their held together pretty well considering the abuse they got.
As the forward head enters ETL....the tendency is for the nose to climb as the forward head is producing more lift than the aft head....an application of forward cyclic cures the pitch up problem but also decreases lift in the aft head...if your rate of acceleration is insufficent to get both heads flying in ETL....major problem.
A very common techique for acheiving MPW performance was to use Yaw pedals to swing the aft head into clean air and combine the sideways rotation of the airframe and the cleaner air to bring the aft head into ETL at the same time as the forward head. Timing was of the essence in that maneuver.
It is great fun to find yourself behind the power/altitude/speed/experience/idea curve with the Mr down from 230 rpm to 190 rpm, gennies dropped off line, and SAS kicked out due to loss of electrics....while holding the thrust level up under your armpit and trying to think up a sound explanation that will satisfy the Accident Review Board.
MPW by the way is the real ACL (Average combat load) for the aircraft as found in reality vice the SOP's.
We asked a lot of the old girls and their held together pretty well considering the abuse they got.
Join Date: Dec 2001
Location: Philadelphia PA
Age: 73
Posts: 1,835
Likes: 0
Received 2 Likes
on
2 Posts
SASless:
MPW - is that a certified, approved term???? (he said, tongue in cheek).
I'd certainly like to use it in future work - it really does say it all.
And wouldn't it be nice if the manufacturer gave you some indication of what sideslip angle gave maximum possible thrust when creeping out with everything on the red line???
MPW - is that a certified, approved term???? (he said, tongue in cheek).
I'd certainly like to use it in future work - it really does say it all.
And wouldn't it be nice if the manufacturer gave you some indication of what sideslip angle gave maximum possible thrust when creeping out with everything on the red line???
Join Date: Sep 2005
Location: US
Posts: 194
Likes: 0
Received 0 Likes
on
0 Posts
Sasless "What bothers me to this day is the guy at the other end did not even know me....and he tried to kill me. I could understand it if he actually knew me."
I know the feeling Sasless. I was growing up in Laos at the time the B52's were dropping more bombs than WWI and WWII combinded down onto Laos' soil. Those guys didn't know me neither, my dad nor my grandpa. I was only three-four years old at the time and from what I heard Laos has never ever attacked the US.
Anyways, grandpa always said that if he ever wanted a new pond, all he had to do was light a small bonfire at the spot that evening and the next morning there'd be a fresh new pond all dug up nice and round for him. I think Nick Lappos knows what I mean by that.
Monk
I know the feeling Sasless. I was growing up in Laos at the time the B52's were dropping more bombs than WWI and WWII combinded down onto Laos' soil. Those guys didn't know me neither, my dad nor my grandpa. I was only three-four years old at the time and from what I heard Laos has never ever attacked the US.
Anyways, grandpa always said that if he ever wanted a new pond, all he had to do was light a small bonfire at the spot that evening and the next morning there'd be a fresh new pond all dug up nice and round for him. I think Nick Lappos knows what I mean by that.
Monk
Join Date: Nov 2004
Location: Cambridgeshire, UK
Posts: 1,334
Likes: 0
Received 0 Likes
on
0 Posts
SASless, thanks again. I always enjoy reading your posts. A lot of experience there - both good and bad...
TheMonk, it is interesting to hear your viewpoint. In Britain we owe a great debt to aviators who in the 40's kept our country free. That was before my time, but i still like make sure that pilots feel the risks they have taken earned my generations respect.
TheMonk, it is interesting to hear your viewpoint. In Britain we owe a great debt to aviators who in the 40's kept our country free. That was before my time, but i still like make sure that pilots feel the risks they have taken earned my generations respect.
Last edited by Graviman; 22nd Sep 2007 at 13:29.
