Flagrum Posted September 22, 2014 Share Posted September 22, 2014 I have no real problem with the way the 21's bake system in conjunction with the rudder pedals work in oder to get around on the airfield. But I wonder how the system actually works. The braking logic is clear to me, I think. You steer with the rudder pedals and if you apply brake pressure, differential braking "happens". But I was a bit surprised, that I can also steer without differential brakes - just with the rudder pedals alone - given that you move at least at a certain speed. The turn diameter is then ofc much larger, but it works really well to align on the taxiway or the runway, etc. But how does that exactly work? Afaik the nose wheel is not steerable? So is the rudder alone, aerodynamically, responsible for that? If so, how can it be so effective - at such low speeds? Link to comment Share on other sites More sharing options...
Aginor Posted September 22, 2014 Share Posted September 22, 2014 Interesting question, I wondered that as well. I would love to know more about the system. :) DCSW weapons cheat sheet speed cheat sheet Link to comment Share on other sites More sharing options...
Corrigan Posted September 22, 2014 Share Posted September 22, 2014 It can't possibly be aerodynamics, that would be utterly unphysical. I was also surprised at what you're talking about. I assume that giving rudder input actually differentially brakes the undercarriage, but I'm not sure that it's working as intended. Was, like you, expecting having to brake with the lever and simultaneously give rudder to get ANY turning at all. Win10 x64 | SSDs | i5 2500K @ 4.4 GHz | 16 GB RAM | GTX 970 | TM Warthog HOTAS | Saitek pedals | TIR5 Link to comment Share on other sites More sharing options...
Grizzly1606688174 Posted September 22, 2014 Share Posted September 22, 2014 I've thought about this as well. No way it's aerodynamics, I can agree to that. Link to comment Share on other sites More sharing options...
MBot Posted September 22, 2014 Share Posted September 22, 2014 Very good question, I have wondered about it aswell. It seems that above about 65% RPM the nosewheel become steerable a little bit. Link to comment Share on other sites More sharing options...
Zooker Posted September 22, 2014 Share Posted September 22, 2014 The brake pads are activated by air pressure (pneumatic). Maybe there is a control valve that is link to rudder movement that directs the air pressure to either wheel and when the rudder neutral the air pressure is allowed to reach both sets of brake pads. I'm intrigued as well...Hopefully someone smarter comes a long...:helpsmilie: VF-111 Sundowners [sIGPIC][/sIGPIC] Carrier Group 1 - Battlegroup Delta Beware the lessons of a fighter pilot who would rather fly a slide rule than kick your ass! -Commander Ron "Mugs" McKeown, USN Commander, U.S. Navy Fighter Weapons School 2 Victories, Vietnam Link to comment Share on other sites More sharing options...
ff4life4 Posted September 22, 2014 Share Posted September 22, 2014 The manual stated that you should taxi between 30 and 50 kph in order to steer without brakes EDIT: should be 40-60 Link to comment Share on other sites More sharing options...
[DBS]TH0R Posted September 22, 2014 Share Posted September 22, 2014 Very good question, I have wondered about it aswell. It seems that above about 65% RPM the nosewheel become steerable a little bit. I too was under impression that at lower speeds you could be only able to steer with brakes. Then I read this: On the MiG-21 F/MiG-21F-13, the nose unit is castoring; steering on the ground is by differential braking. Late versions have a hydraulically steerable nose gear unit. Source: http://www.kamov.net/general-aviation/mig-21-landing-gear/ As it stands now, the plane with nose breaking disabled will turn even with rudder movement only at speeds lower than 5 km/h. P8Z68 | 2500k @ 4.5 | GTX 1080Ti | 2x8 GB @ 1600 | TM Hog (extended 7cm) & MFG Crosswind (S/N 007) | TIR v5 WWII bomber formations | DCS P-51D: [TEST] TO distance / gross weight / temperature Link to comment Share on other sites More sharing options...
Luzifer Posted September 22, 2014 Share Posted September 22, 2014 Very good question, I have wondered about it aswell. It seems that above about 65% RPM the nosewheel become steerable a little bit. That's been my experience, too. I was steering during taxiing without using the brakes unless I need to do a really tight turn. And I noticed that at lower engine RPM steering doesn't work as well or at all. Link to comment Share on other sites More sharing options...
Dejjvid Posted September 22, 2014 Share Posted September 22, 2014 There's only one logical explanation. A pnuematic valve is linked to the rudder and applying the brake as you move the rudder. The maximum force that you can apply with rudder alone is limited, that's why you need to apply brake in order to turn tight. i7 8700K | GTX 1080 Ti | 32GB RAM | 500GB M.2 SSD | TIR5 w/ Trackclip Pro | TM Hotas Warthog | Saitek Pro Flight Rudder [sigpic]http://www.132virtualwing.org[/sigpic] Link to comment Share on other sites More sharing options...
Tango Posted September 22, 2014 Share Posted September 22, 2014 (edited) You are mixing multiple things. DIFFERENTIAL BRAKES are linked to the rudder, and require use of the brake handle, period. NOSE WHEEL STEERING LINKED TO THE RUDDER is something else entirely, and the aircraft behaves like this only connects at speeds > 40 kph (to me it seems more like 25 kph). Thus, when taxiing VERY SLOWLY, the ONLY way to turn is with DIFFERENTIAL BRAKING. At high speed (let's say 100 kph) then NOSE WHEEL STEERING is available. I'm very intrigued as to why it doesn't have full-time nose wheel steering, and how the system works. Best regards, Tango. Edited September 22, 2014 by Tango Link to comment Share on other sites More sharing options...
eyusuf Posted September 22, 2014 Share Posted September 22, 2014 There's only one logical explanation. A pnuematic valve is linked to the rudder and applying the brake as you move the rudder. The maximum force that you can apply with rudder alone is limited, that's why you need to apply brake in order to turn tight. Ok that does it. I'm going to watch some porn. Link to comment Share on other sites More sharing options...
Fishbreath Posted September 22, 2014 Share Posted September 22, 2014 The MiG-21 fighter maneuverability in today's terms document (or whatever it's called) in another thread claims that the MiG had extremely good low-speed rudder authority, down to as little as 30 kts (~50kmh). It could just be aerodynamics at fast taxis. (And presumably that's why the manual/procedures say to taxi at 50-60kmh, so you don't have to spend your compressed air on keeping centered on the taxiway.) Black Shark, Harrier, and Hornet pilot Many Words - Serial Fiction | Ka-50 Employment Guide | Ka-50 Avionics Cheat Sheet | Multiplayer Shooting Range Mission Link to comment Share on other sites More sharing options...
[DBS]TH0R Posted September 22, 2014 Share Posted September 22, 2014 Thus, when taxiing VERY SLOWLY, the ONLY way to turn is with DIFFERENTIAL BRAKING. At high speed (let's say 100 kph) then NOSE WHEEL STEERING is available. I'm very intrigued as to why it doesn't have full-time nose wheel steering, and how the system works. Not as it is currently simulated. In training taxi mission I can turn without brakes with or without nose wheel brake with as little as 10 km/h and power between 70-80%. If this is the correct behavior then obviously there is some kind of a pneumatic device that engages only after power is advanced to 70-80% and is linked to the rudder movement (i.e. nose wheel steering). P8Z68 | 2500k @ 4.5 | GTX 1080Ti | 2x8 GB @ 1600 | TM Hog (extended 7cm) & MFG Crosswind (S/N 007) | TIR v5 WWII bomber formations | DCS P-51D: [TEST] TO distance / gross weight / temperature Link to comment Share on other sites More sharing options...
ff4life4 Posted September 22, 2014 Share Posted September 22, 2014 FROM THE MANUAL "When the aircraft starts to move, press brakes again to check if braking is even and then release the brakes to continue your taxi. If you taxi straight from your parking place, allow the aircraft to gather about 40-60km/h (20-30nmi/h) then decrease the power to maintain that speed (~65%). At this speed you will be able to use the rudder to maintain direction, so you’ll avoid wasting compressed air when braking to maintain direction. However, if you are making turns, you need to decelerate to 15-20km/h (9-11nmi/h) and use rudder controls and brakes to turn the aircraft." Doesn't really explain much. I only wonder if the BLC system is somehow effecting this Link to comment Share on other sites More sharing options...
ff4life4 Posted September 22, 2014 Share Posted September 22, 2014 BLC blows air from the top of the flap. Could this air also make the rudder more effective?? If its modeled in the sim Link to comment Share on other sites More sharing options...
Art-J Posted September 22, 2014 Share Posted September 22, 2014 It is modelled, but I struggle to see how it would affect rudder, being a bit too far away and blowing in different direction. i7 9700K @ stock speed, single GTX1070, 32 gigs of RAM, TH Warthog, MFG Crosswind, Win10. Link to comment Share on other sites More sharing options...
ff4life4 Posted September 22, 2014 Share Posted September 22, 2014 Its blowing straight back from the top of the wing Link to comment Share on other sites More sharing options...
Justin Case Posted September 22, 2014 Share Posted September 22, 2014 Maybe, when LN started to make their first flight test model they started with a simple propeller driven aircraft. And since then they forgot to delete the prop wash and that's what we are seeing here, it makes perfect sense! Case closed, move along guys. http://www.masterarms.se A Swedish Combat Flight Simulator Community. Link to comment Share on other sites More sharing options...
WildBillKelsoe Posted September 22, 2014 Share Posted September 22, 2014 You need to apply partial brakes (not reaching 50% even) and keep speed below 50 km/h (65% or less power) to have sufficient nosewheel steering. I don't have problems taxiing this bird but I takeoff without holding the brakes but gradually till reaching full afterburner. AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow. Link to comment Share on other sites More sharing options...
Art-J Posted September 22, 2014 Share Posted September 22, 2014 (edited) Ff4life4, yep it does, back and down along the top of blown surface, like every blown flaps system, or even normal slotted or Fowler flap, just harder. In either case, the air ends up under the elevators and clearly nowhere near the rudder. WildBill - nobody has problems taxying this bird, we're just curious what makes the plane turn at low speeds even WITHOUT using brakes, when: a) nose wheel is supposedly free-castoring; b) rudder ain't working, because there's clearly not enough airstream hitting it. Edited September 23, 2014 by Art-J i7 9700K @ stock speed, single GTX1070, 32 gigs of RAM, TH Warthog, MFG Crosswind, Win10. Link to comment Share on other sites More sharing options...
Corrigan Posted September 22, 2014 Share Posted September 22, 2014 Maybe, when LN started to make their first flight test model they started with a simple propeller driven aircraft. And since then they forgot to delete the prop wash and that's what we are seeing here, it makes perfect sense! Case closed, move along guys. Clearly I'm the annoying person. Win10 x64 | SSDs | i5 2500K @ 4.4 GHz | 16 GB RAM | GTX 970 | TM Warthog HOTAS | Saitek pedals | TIR5 Link to comment Share on other sites More sharing options...
[DBS]TH0R Posted September 22, 2014 Share Posted September 22, 2014 WildBill - nobody has problems taxying this bird, we're just curious what makes the plane turn at low speeds even WITHOUT using brakes, when: a) nose wheel is supposedly free-castoring; b) elevator ain't working, because there's clearly not enough airstream hitting it. That! P8Z68 | 2500k @ 4.5 | GTX 1080Ti | 2x8 GB @ 1600 | TM Hog (extended 7cm) & MFG Crosswind (S/N 007) | TIR v5 WWII bomber formations | DCS P-51D: [TEST] TO distance / gross weight / temperature Link to comment Share on other sites More sharing options...
Tango Posted September 22, 2014 Share Posted September 22, 2014 WildBill - nobody has problems taxying this bird, we're just curious what makes the plane turn at low speeds even WITHOUT using brakes, when: a) nose wheel is supposedly free-castoring; b) rudder ain't working, because there's clearly not enough airstream hitting it. Fixed! :P Best regards, Tango. Link to comment Share on other sites More sharing options...
Art-J Posted September 23, 2014 Share Posted September 23, 2014 Oh dear, how the hell did this "elevator" slip in here? I think I'll better read what I write before hitting "post" button :D. i7 9700K @ stock speed, single GTX1070, 32 gigs of RAM, TH Warthog, MFG Crosswind, Win10. Link to comment Share on other sites More sharing options...
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