Decelerating/Transitioning from Cruise to Hover

[CrimsonGhost]

As the title says, I am curious what procedure is typically used to decelerate quickly from cruise to get into position for hover? I have been pitching up and lowering the collective but it seems to take forever to bleed off airspeed. This typically works with standard configuration helicopters, but does the coaxial rotor system change this at all? Some pro tips would be greatly appreciated. Thanks.

Edited March 7, 2016 by CrimsonGhost
Title change

[Bucic]

Do you lower the collective all the way down?

If significantly lowered collective does not lead to satisfactory rate of deceleration, you're going to have to resort to sharp turns. Two quick ones should be enough to slow down even from maximum airspeed.

[CrimsonGhost]

Yep, been dropping the collective completely, and adding it back in as I get lower while making sure not to over torque. Will have to experiment with turns. I'll post what I find after some testing.

[Bucic]

During my very first flight hours in DCS I faced a similar problem. It took me too long to decelerate when a threat appeared around 4 km in front of me and if I tried to make a hard turn (to decelerate or change the direction of flight) I often found myself falling out of the horizontal plane too much. What I did to address that was at least an hour of the following exercise:

Flying over a rectangle marked by a typical airfield runway and the parallel taxiway more or less trying to:

- enter each corner at as high airspeed as possible (literally; not "comfortable for the next turn")

- execute each corner as tight as possible

- never pop over ~50 m of altitude

 

I also extended the rectangle from time to time if I wanted to practice breaking turns at an airspeed of more than 250 km/h.

Give it a try.

Edited March 7, 2016 by Bucic

[StrongHarm]

When I want to stop immediately I'll get the right side of the bird facing my direction of flight, roll the bird left(rotor facing away from direction of flight), then pump the collective. Kind of like sliding into homebase. You can stop pretty rapidly using this maneuver.

[StrongHarm]

I should have mentioned; pumping the collective works on level decel too. Drop the collective out then pump 1 or 2 second bursts of collective pull. Pumping the collective does not increase your altitude but rather acts like a brake. The alternative is to find the sweet spot in the collective to maintain altitude while still decelerating. Pumping gives you finer control, whether it's faster pumps or precision pump cycles.

[Nerd1000]

I use a tight 360 degree turn when I need to stop quickly.

[Raptor9]

Just lower the gear, touch down, and apply brakes :smartass:

[IonicRipper]

I think the reason why it takes so much longer to stop the Ka-50 compared to say, a Huey, is not because it doesnt slow down as fast using conventional technique but rather because of how fast the BlackShark can actually go. It doesnt take any longer to stop it from 100 kts then any other fling wing IMO. I think the best way to counter this is anticipate and start slowing down earlier.

[kilix]

and also, the Ka-50 is heavy. It is smaller, but heavier than a Mi-8 (without cargo). So aerodynamic drag is smaller, while it is a faster and heavier aircraft=more inertia. I started with Mi-8 just recently, but I immediately noticed how fast it is able to stop compared to Ka-50. I think, that a bigger rotor diameter counts when stopping/accelerating. Someone more knowledgeable should enlighten us, how single bigger rotor compares to two counter rotating smaller rotors acceleration-wise.

 

And as IonicRipper said, anticipate that and fly accordingly. For example, when you are in a battlezone and you expect you will have to do sharp turns or stop without warning, never go faster than 150~170km/h.

 

Also, I found out, that I am able to stop pretty fast doing this> 300-150km/h braking by pulling cyclic, nose to ~20-25°, collective down, watch VVI, not to climb or fall, adjust collective accordingly. At about 130-150kmh turn sharp left, nose to about 5°, collective up and stop by skiding to the side, like a skier, when he passes the finish line. Also, using this maneuver, you dont need to watch VVI religiously, you can look out of the big left window and estimate your vertical velocity by observing the relative ground movement below you. This works for me :)

 

I may review the exact numbers in this last paragraph when I get home and try this, I'm not exactly sure about the figures, I do it by 'feeling the right speed', so take it as a rough estimate :)

Edited March 8, 2016 by kilix
added last paragraph

[FeistyLemur]

I like to nose it up and to the left and flip it around hard with the ruder that has a tendency to really get rid of momentum, and you can see what you're looking for out your left window. Such as a FARP you're about to land at or possibly a target area you're preparing to funnel around. I'm only really beginning to learn and get more proficient at the funnel manouver, but it sure feels good when you pull it off properly.

Edited March 8, 2016 by FeistyLemur

[CrimsonGhost]

Thanks for all the suggestions. I will have to give these a try. If anyone ever cares to join up I can usually be found on the Open Conflict server after work each morning. Usually 1300Z-1500Z. This is my go to server to try out new modules and practice.

[StrongHarm]

FeistyLemur, practicing the funnel is when I truly started to understand the airframe. Before that I would 'transition' the flight controls smoothly like I was flying fixed wing.

 

I practiced the funnel by orbiting various objects at the airbase while keeping my nose pointed at the object. I tried it at various speeds and altitudes, then entering and exiting funnel after a fixed amount of orbits. Eventually I found that rotor and fixed are vastly different where flight controls are concerned. Now, the only time collective/cyclic/rudders aren't all in constant motion is when I'm in straight and level flight. in my opinion, fixed wing is like playing the cello, rotor wing is like playing the drums.

[DieHard]

Just lower the gear, touch down, and apply brakes :smartass:

 

Yep!

 

And be prepared if you encounter the state where you just drop out of the sky (vortex ring state).

 

I can stop dead in hover in less than 30 seconds from full speed. I pitch up steeply, drop the collective dramatically (pump it), and click the trimmer, in about 3 or 4 sets.

 

I am usually in Flight Director.

 

I do use AP back to the airfield (if it is still working) once out of harms way and I am down low.

Edited March 12, 2016 by DieHard

[FeistyLemur]

FeistyLemur, practicing the funnel is when I truly started to understand the airframe. Before that I would 'transition' the flight controls smoothly like I was flying fixed wing.

 

I practiced the funnel by orbiting various objects at the airbase while keeping my nose pointed at the object. I tried it at various speeds and altitudes, then entering and exiting funnel after a fixed amount of orbits. Eventually I found that rotor and fixed are vastly different where flight controls are concerned. Now, the only time collective/cyclic/rudders aren't all in constant motion is when I'm in straight and level flight. in my opinion, fixed wing is like playing the cello, rotor wing is like playing the drums.

 

The funnel is tough to master, or at least I'm finding. The "shooting range" instant action mission provides a great practice environment. I like to practice circling all the dummy targets and killing the tanks from above in a funnel with 30mm AP from the cannon. It really does those dummy T55s in fast when you hit them from above and behind.

 

I've been doing the "deployment" campaign just now and I had a really fun mission experience. I was doing the 8th mission I believe it is. Where you have to fly through the high mountain pass from Nalchik and assault forces in a valley with the help of some SU24 bombers.

 

The air defenses were mostly out or so i thought, so I had just ordered my wingmen to open fire on all ground targets and I was at a hover nearby looking through my shkval about to line up targets myself when I saw an SA18 flying at me through the shkval. Well ****. It hit me and took out my hud, shkval, etc. So I limped into cover putting out flares and avoiding more SA-18s. So I'm sitting there behind a hill blind while my wingmen are ripping the place up. So I think **** it I'm going in rambo style. So I switched to KOM rockets and decided im going in and trying rocket runs with no sights.

 

So I got sprayed with machinegun fire from a BTR80 as soon as i came around the corner. That was it for the cannon and hydraulics systems as I saw those going. I dropped the gear immediately having learned to do that immediately when hydro is going. So I keep circling the field with no stabilization autopilot, hud or sights. Just my blind fire rockets by pointing the nose of my chopper at targets. I managed to take out that BTR and a few trucks while my wingmen mopped up the last of everything and the mission was a success. I had to give up and end the mission there with no way to make the long flight back to Nalchik without any instrumentation left working and barely able to hold the thing steady. But it was the most fun I've had with the black shark yet.

 

Come to think of it I haven't found any other module that's such a rewarding single player experience. The first campaign for the black shark is just a ton of fun so far.

Edited March 8, 2016 by FeistyLemur

[zerO_crash]

For those of you who don`t understand why it is as such, here are the main reasons:

 

1. Ka50`s rotor is leaned forward a fair bit more than that of the Mi8. This is a specific design feature, and therefore you have to remember that this should be counted when directly comparing both. The difference is minuscule, but still there. For you, this means in practice, pull slightly more on the cyclic when slowing down in Ka50.

 

2. Aerodynamic shape. The difference is huge between aerodynamic performance of Ka50 and Mi8, plus that the higher the speed, the more exponential this function becomes. Mi8 having bigger front, and bigger bottom, will indeed slow down faster as a matter of drag induced by front and lower body. The Ka50 is aerodynamically incredibly well performing.

 

3. You probably don`t notice this yourself, but with Ka50 you tend to fly faster than with Mi8, plus that you tend to fly with more weight, normally. With Ka50, you`d fly 250+ km/h fully loaded (regardless of loadout composition) around 10 500 kg - 11 000kg, whereas if you went with full Mi8 load (weapons/cargo) around 9 500kg - 11 000kg, she will start shaking above 210/220, depending on altitude and air pressure, this will naturally make you decrease the speed to a lower one. Keep in mind that if you tested Ka50 at the same speeds and weights as Mi8, you wouldn`t see much difference.

 

!Rotor layout has nothing to say in this case as although they work completely different, the effect is the same lift mechanic. Therefore, if anything, the difference lies in disc area, which is approx. Ka50 (330m^2) vs Mi8 (350m^2). This then means that Mi8 has can induce more drag with it`s rotor when braking and accelerating. Keep in mind that this only counts when both helicopters are measured with similar respective weight. As Mi8 can weight max. in at 13 000kg (vs 10 900kg of ka50), the extra 20m^2 of disc area will make it have lesser ratio of disc area to gross weight. Just a side note. Also, the "official" max. weights can by bypassed, so that`s yet again something to count in.

 

These are the basic reasons, there are of course more things that come into play such as: altitude tested, degree of pitch, air pressure, ambient air temperature, etc.....

 

For you to know how to handle a quick deceleration in Ka50, it`s a matter of performing the right manoeuvres depending on the situation and effect desired. You can trade KE (kinetic energy - velocity in any horizontal vector) for PE (potential energy - altitude) by pulling on collective, or even more efficient pulling on the cyclic and gaining altitude while loosing speed. It all depends on what environment you fly in and thus what manoeuvres you restrict yourself to.

Edited March 8, 2016 by zerO_crash

[StrongHarm]

So I keep circling the field with no stabilization autopilot, hud or sights. Just my blind fire rockets by pointing the nose of my chopper at targets. I managed to take out that BTR and a few trucks...

 

That reminds me.. another practice that helped my funnel maneuvers was to turn heading and alt autopilot off. I keep pitch and bank AP on.. but turn heading and alt off. The bird is still perfectly stable, but you don't have to fight the AP. I've bound AP channels to my TM Warthog as follows:

 

CMS FWD - HDG

CMS LFT - BANK

CMS RGT - PITCH

CMS DWN - ALT

CMS PUSH - Emergency off

 

The only time I use emergency AP off is when I'm evading a missile or something extreme like that. After turning off my AP HDG and ALT, I felt like a real fool for holding my Trim for literally hundreds of hours previously. Particularly because when you turn HDG AP back on, your AP locks the new heading (just as trim does)

[kilix]

or you can fly with FD on. I do, I think it is more natural to my tastes. I can fly perfectly well without it, but it doesn't feel right for some reason. Only transitions between known safe WPs are done without FD.

 

ofc, any maneuver is done better when you don't have to fight the AP and hold the trimmer down for the entire duration of said maneuver.

[FeistyLemur]

I definitely fly in flight director mode most of the time now. I love it. I haven't compared to turning off the individual channels but I'll have to try that as well. Once the hydro system is dead though it really becomes interesting to fly.

[Rogue Trooper]

Lots of good advice here... each needs confidence but all advice is gold.

In an emergency slow down due to targets or threats then I reach for one switch... all APs go offline immediately.

After that all the above suggestions are is easy to achieve on the width of a dime:smartass:

 

I like to turn with hard rudder, speed loss is violent but allows you to transition forward speed into lateral speed so that VRS is not a threat. Within a second you are funneling your hover point and then sliding in side ways into position whilst simultaneously re engaging the APs and trimming to hover.

 

Cyclic control

Collective control

Rudder control

Track IR or some other ease of use viewer.

 

Each and every one of the list above are vital adjustments that effect each other in a chopper.

 

I got a feeling a vibro seat might join that list soon (for me at least).

[Toast]

A tip for transitioning to a hover is once you get under 50 kph, a line will appear in the center of the hud, (you have to be in the main hud mode, backspace will get you back to main hud mode) that line is an aid that will help you get into a hover. Simply apply cyclic in the opposite direction of the line, and the length of the line is the how much cyclic to use.

[StrongHarm]

A tip for transitioning to a hover is once you get under 50 kph, a line will appear in the center of the hud, (you have to be in the main hud mode, backspace will get you back to main hud mode) that line is an aid that will help you get into a hover. Simply apply cyclic in the opposite direction of the line, and the length of the line is the how much cyclic to use.

 

Yes! I was happy when I figured this out. I use it to determine if I have drift while in auto-hover. It allows you to trim up if wind or terrain are causing issues staying in one spot. Prior to figuring this out I used to stare down at the ground until I was sure I wasn't drifting hahah.

[Bushmanni]

http://forums.eagle.ru/showpost.php?p=2033616&postcount=1035

 

http://forums.eagle.ru/showpost.php?p=2033734&postcount=1037

[StrongHarm]

No matter whether you use the pitch method or the roll/yaw method, pumping the collective will stop you about 50% faster. When I say pump, I don't mean frantically like you would a Swedish made pe.. nevermind that.. what I really mean is that you slowly lower and raise it. The pump rate depends on a lot of factors... but it should be in constant motion until you are stationary.

 

EDIT: Although this is a fixed wing throttle rather than a collective, this video displays what I mean by pumping the collective: https://gfycat.com/HappygoluckyFrenchBluefish

Edited April 5, 2016 by StrongHarm
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