Some complete newbie questions

[baltic_dragon]

Hey guys,

 

First of all - thanks a lot for the Gazelle. It is actually the first helo that really got my attention and as soon as my Crosswind rudder pedals arrived about the same time as Gazelle was out, I decided to give it a go... and realised I know nothing about piloting a helicopter.

 

I mean, I do understand the basics, like more collector power = going up and faster, nose down = more speed, nose up = slowing down etc. After some trials I managed to get Gazelle into the air without spinning like crazy, but I still seem to glide ahead before I take off and I can't slow down below 80 km/h, because if I do she starts doing some crazy things.

 

So I thought that I would need some really newbie advice and information (perhaps useful not only for me, but also others). And you helo-veterans should have lots of useful links, tutorials, documents etc. not only Gazelle specific, but also general ones.

 

So thanks in advance for a crash course in helicopter flying :thumbup:

[HoneyBadger]

This video is for the Huey but I feel it does teach the principles of helicopter flight well enough to apply to any heli-sim.

 

He stresses the importance of a FFB joystick, but you don't need to worry too much about them. If you can somehow get a decent one, nice, but me and everyone else I know doesn't have one and we do just fine in Heli's.

 

(ignore this) Another thing to note, the torque from the Huey's clockwise spinning blade (this is explained in the video) will push the heli right at low speeds so you need to apply left rudder to keep it straight. The Gazelle also spins clockwise but you need to apply right rudder to keep it straight for reasons that I'm sure someone more knowledgeable than me can explain. (ignore this)

Edited May 8, 2016 by HoneyBadger

[spiddx]

Huey's blades spin CCW... ;)

[HoneyBadger]

Huey's blades spin CCW... ;)

 

I haven't flown the Huey in awhile...

[YoYo]

Hey guys,

 

First of all - thanks a lot for the Gazelle.....

 

Hi Baltic, some of aspects of flying on helicopter I wrote in the text about Take on Helicopter:

http://yoyosims.pl/Takeonhelicopters.html

http://yoyosims.pl/TOHAddons.html

And UH-1/Mi-8 review: http://yoyosims.pl/dcs-uh-1h-huey

Maybe it helps a little ....

[Mt5_Roie]

Helicopters a different aircraft then planes in a lot of ways. But one thing I hear people say is they think the collective increases and decreases throttle. This is not true at all. Most helicopters have a set throttle that rarely gets touched in flight. What the collective does is modify the angle of the planes to increase or decrease pitch.

[baltic_dragon]

Thanks guys, will give it a try! After flying with Yurgon tonight I managed to land in one piece :) Great fun to fly a helo!

[Sryan]

Hey Baltic!

 

The collective lever is, like others have stated, not a synonym for throttle. It does not affect the engine output. They instead affect the Angle of Attack (AoA) of the rotorblades. Increasing the collective increases the AoA and therefore, the lift. A notable DCS module is the Ka-50. Where you can operate the throttle and the collective seperatly, although you typically use the automatic governors that apply engine power as necesary automaticly.

 

This is something important to understand if you would ever find yourself in a situation where you lose all engine power. The only way to survive is to enter a state of autorotation. If you lose all power but keep collective applied your blades will maintain their AoA, and provide lift. This spends energy that is stored in the momentum of the blades, energy that is no longer being refreshed by the engine. You can sustain flight for some time untill the blades lose enough energy to sustain flight. You can see the blades slowing down and you die unavoidably.

 

If you instead immediatly nullify the pitch angle on your rotorblades. You start losing altitude very fast. But as the rotorblades are not providing lift. They are not losing energy, not as fast as they would otherwise in any case. The loss of altitude may even send air "up" through the rotordisk providing additional energy. This is called windmilling. When you are in a suitable position. You can increase the collective, therefore increasing the AoA and lift and spend the little energy you have to bring the helicopter under control and do an emergency landing.

 

The joystick in a helicopter is not called as such in a helicopter. But a cyclic. The cyclic also adusts the rotorblade pitch and therefore AoA and lift. But instead of doing all the rotorblades at once, the cyclic only affects the rotorblade in a specific position in the circle. Therefore increasing lift locally causing the rotordisk to tilt and the helicopter to respond to the commands. In reality this is even more complicated than it already sounds. As the helicopter must also deal with manifestations from the laws of physics like gyroscopic precesion. Meaning the action will not become manifest untill 90 degrees further in the cycle from where the force is applied. So if I am not mistaken. If you want to bank the Gazelle to the right, the pitch action must occur in the front.

 

You're a known person on these forums for making campaigns. So you obviously understand what aircraft are about. I therefore I assume you understand what IAS, Indicated Airspeed means. Take a moment and think not about how IAS is applied to the helicopter as a whole, but to each individual rotorblade. If you are parked or in a hover, IAS is the same for every rotorblade, am I right? But if you start to move forward at a considerable speed. IAS is not equal everywhere anymore.. The blade that moves 'into the wind' has more IAS, but the blades that moves 'away from the wind' has lower IAS. This causes Dissymetry of Lift. A tendency for the helicopter to roll. If the speed is increased further. Tip stalling may occur. The tip of the retreating blade then stalls. This is noticed by extreme helicopter vibrations and serves as a 'last warning'. If speed is further increased Retreating Blade Stall will occur. A likely cause of death for that flight. This is the most important 'cap' on helicopter maximum speed.

 

However the most probable non-combat related helicopter fatalities is probably VRS, Vortex Ring State. When you are in a hover you may want to decent to land or to find cover. However if you descend to fast, you descend into your own 'bad' air. If you descend to fast in this bad air, that bad air will get sucked up straight up through the rotordisk. Nullifying it's effectiveness and causing you to crash like a brick. If you detect VRS Early

it's possible to overpower the effect. If you detect VRS late you must lower the collective and provide forward cyclic in order to escape from the bad air.

 

A wing that moves faster provides more lift, right? After all, planes standing still on the tarmac don't exactly fly? In helicopters this effect is further "boosted" by something called translational lift. Sucking in sufficient air is a problem for a hovering helicopter. however as speed is increased, this problem lessens, and it is easier to provide lift, at a certain forward speed, Finding fresh air is no problem at all anymore! If you want a demonstration of this. Put the helicopter in a hover. Try to climb as fast as you can. The results won't be that impressive. Now climb while in fast forward flight. Much better! Even without using zoom climb you can do way more meters per second in the vertical than you can ever dream of in a hover. What's important here is that the REVERSE counts as well! when you transition from forward flight into a hover you MUST expect to apply more collective in order to provide enough lift to sustain flight, otherwise you transition not into a hover but straight into a VRS :) This effect is why helicopters, like airplanes, like to take-off into the wind.

 

The last thing I want to talk about is torque. I assume you understand a little what torque does for a helicopter. The fuselage receives as much rotational force as the rotorblade does. The Fenestron tail must counter that torque. It's important to realise that every time you manipulate the collective, the total amount of forces acting on the helicopter changes. So everytime you touch the collective you should expect to manipulate the pedals as well. At a fast enough forward speed the horizontal stabilizer and the default tailrotor settings are typically enough to counter torque.

 

I hope this helps shed some light :) I used the 'lively' examples of dieing to highlight whats important.

 

I recommend you download the Ka-50 manual. Not to read about the helicopter but to read the chapter "helicopter fundamentals". I provided you with a download link. Immediatly navigate to page 50. You will see explanations like mine but more, including useful diagrams and visualisations of the effects at hand.

 

[ame=http://www.foinikas.org/ftp/public/DCS%20Blackshark/DCS-BS_Manual_EN.pdf]http://www.foinikas.org/ftp/public/DCS%20Blackshark/DCS-BS_Manual_EN.pdf[/ame]

 

xxjohnxx has a tutorial series on the gazelle: http://forums.eagle.ru/showthread.php?t=165761

 

I have also made a single tutorial about trimming for hover and flight: http://forums.eagle.ru/showthread.php?t=165978

 

I think John made a video about the same subject as well, though. I made mine a few days earlier. I haven't watched his so I don't know wich one is best. I only know mine works for me :)

 

I haven't tested the manifestations of the forces I explained in the Gazelle yet. I flew the Gazelle a lot when I bought it but I have been doing other things that kept me extremely busy ( you know exactly what ;) )

 

Hope it was helpful! have a nice day!

 

*Disclaimer, I am not a real pilot and gladly fix any mistakes in my explanations pointed out if I made any*

Edited May 9, 2016 by Sryan
spelling and grammar

[baltic_dragon]

Many thanks to everyone, now I am well equipped to go ahead and practice! Cheers!

[Flagrum]

some lecture :smartass:

 

FAA Helicopter Flying Handbook