Question: How stiff are the pedals on your helo?
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Question: How stiff are the pedals on your helo?
Just curious about how stiff the pedals are on the helicopter you usually fly, and do they have any weird quirks like a center detent or anything?
I.e. is it stiff enough to give you leg cramps like a Cessna or light enough that you don't get much tactile feedback from the pedals?
Thanks!
I.e. is it stiff enough to give you leg cramps like a Cessna or light enough that you don't get much tactile feedback from the pedals?
Thanks!
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I've never flown a helicopter on which stiff pedals were the norm. If they're stiff, something is wrong. And I've never heard of a "center detent" in one. Some have lighter pedal forces than others, but they shouldn't be stiff. Smaller helicopters have direct coupling, but larger ones require hydraulic assist. The forces on these can usually be adjusted to some extent.
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Pedal force requirements are not constant. In the hover I don't want over sensitive light pedals if I'm trying to hold a heading but if transitioning to the hover I don't want to faint from the effort of moving the pedals. Gazelle had hydraulic dampers in the pedals to modify the forces depending on how fast you moved the pedals - although probably more to stop block footed pilots starting a left yaw too fast and precipitating the phenomenon known as Fenestron Stall (it doesn't actually stall of course)). Aircraft with levels of augmentation can have some variation in force too - some have force breakouts which hold the pedals still so the AFCS can do its thing but transparent release if the pilots chooses to take over. Others have micro switches which have sudden change between the two modes - not so cool.
I think a consistent high force chosen at the design stage would rapidly annoy pilots whereas light firces light be just described as twitchy. When comparing with fixed wing, they don't have to make spot turns in the hover, nor level out from an autorotative descent. When they do need lots of pedal they have rudder trim (light piston twins).
If your helicopter suddenly has stiffer controls its definitely bad but differences between types not so clear cut.
I think a consistent high force chosen at the design stage would rapidly annoy pilots whereas light firces light be just described as twitchy. When comparing with fixed wing, they don't have to make spot turns in the hover, nor level out from an autorotative descent. When they do need lots of pedal they have rudder trim (light piston twins).
If your helicopter suddenly has stiffer controls its definitely bad but differences between types not so clear cut.
On the Huey, with the engine running (and hydraulics on) you could tap one pedal (with the feet off the other pedal) and it will motor all the way to the stop - causes some consternation to ground crew if you are sitting on PSP or some other slippery surface.
As Gomer says, there is little feel to a hydraulic pedal, and even on the R22 there is almost no feel - when in a stable hover it is possible to lift the left foot off the pedals, and the right foot is applying just a little pressure to hold the position (which is left pedal forward a bit, of course - but the pedals want to go further left-forward, so the right toe stops this.)
As Gomer says, there is little feel to a hydraulic pedal, and even on the R22 there is almost no feel - when in a stable hover it is possible to lift the left foot off the pedals, and the right foot is applying just a little pressure to hold the position (which is left pedal forward a bit, of course - but the pedals want to go further left-forward, so the right toe stops this.)
When we received our OH-58A's which had un-boosted Tail Rotor Pedals but the standard Jet Ranger style boosted Cyclic/Collective system....coming from the Huey to the Kiowa took some getting used to as the Pedals were hard to move on the Kiowa and very light on the Huey. The mismatch between the boosted flight controls (very light) and the Pedals (Hard to move) confused the Monkey Memory skills for a while.
If you add in Force Trim as on the Huey, 212, 412 and other Types of Helicopters then you can get a "Detent" effect when you reference the controls by means of the Force Trim system. That Detent moves with each application of the Force Trim system by either the On/Off Switch or the Cyclic Release Switch.
The Hughes 500 Pedals were easy to move but sometimes due to T/R rigging would want to creep in one direction or another and had to be braced with a Toe to prevent that.
If you add in Force Trim as on the Huey, 212, 412 and other Types of Helicopters then you can get a "Detent" effect when you reference the controls by means of the Force Trim system. That Detent moves with each application of the Force Trim system by either the On/Off Switch or the Cyclic Release Switch.
The Hughes 500 Pedals were easy to move but sometimes due to T/R rigging would want to creep in one direction or another and had to be braced with a Toe to prevent that.
The control linkages for the foot pedals installation are identical to the basic helicopter, with the exception of a pedal friction mechanism with a preset friction tension. The pedal friction mechanism (500N only) offers the pilot an artificial feel or workload of a conventional tail rotor system.
http://download.mdhelicopters.com/et...0/67203040.pdf
Anti−Torque Pedal Friction Installation
(1). Using two pieces of wood and C-clamp or rope, secure pilot's pedals in mid position so they are aligned within 0.50 inch (1.27 cm) of each other.
(2). Install washer, bolt, bushing, and link assembly to bracket assembly on instrument console.
(3). Install brace and clamp arm assembly to anti-torque tube assembly.
(4). Install friction disc, link, retainer and spring, install washer (shim washers if required) and nut.
(5). Torque brace and arm assembly bolts 30 - 35 inch-pounds (3.39 - 3.95 Nm). Torque nut against washer to obtain a pedal friction of 5 - 8 pounds (2.27 - 3.63 kg)
http://download.mdhelicopters.com/et...0/67203040.pdf
Anti−Torque Pedal Friction Installation
(1). Using two pieces of wood and C-clamp or rope, secure pilot's pedals in mid position so they are aligned within 0.50 inch (1.27 cm) of each other.
(2). Install washer, bolt, bushing, and link assembly to bracket assembly on instrument console.
(3). Install brace and clamp arm assembly to anti-torque tube assembly.
(4). Install friction disc, link, retainer and spring, install washer (shim washers if required) and nut.
(5). Torque brace and arm assembly bolts 30 - 35 inch-pounds (3.39 - 3.95 Nm). Torque nut against washer to obtain a pedal friction of 5 - 8 pounds (2.27 - 3.63 kg)
Last edited by Senior Pilot; 17th Jan 2016 at 19:34. Reason: Fix cut and paste pagination!
Paradoxbox - if you are experiencing a 'centre-detent' feeling in your yaw pedals, it could be due to Brinelling.
When the tail rotor drive shaft - the bit actually attached to the TR and driven by the TR gearbox - rotates in its pitch change bearings in the same position (cruise flight at constant speed for example) the bearings can wear a groove in the drive shaft - the is Brinelling.
We sometimes saw this in the Wessex and it manifested itself in the 'centre-detent' feeling where more force was required to get the bearing to 'climb out' of the groove.
When the tail rotor drive shaft - the bit actually attached to the TR and driven by the TR gearbox - rotates in its pitch change bearings in the same position (cruise flight at constant speed for example) the bearings can wear a groove in the drive shaft - the is Brinelling.
We sometimes saw this in the Wessex and it manifested itself in the 'centre-detent' feeling where more force was required to get the bearing to 'climb out' of the groove.
