Jump to content
Y-29.Silky

Yakcopter or Automatic flaps? + Video

Recommended Posts

The thread I was responding to was locked but I just wanted to post something. 

 

I am by no means a Luftwhiner, I'm actually quite the opposite, but I do notice something..
When a Yak pilot forgets to raise his flaps while climbing straight vertical and comes out of it without stalling,
is a tad bit ridiculous and borderlines thrust vectoring.

 

Jj1klVr.png?1

 

I don't want this thread locked, not trying to start a flame war, I'm just posting evidence of something that I think should be looked at in general.

Quite honestly the problem could be in the automatic flaps function, the only reason why I was able to pull that loop in the 190 in the first place was due to my flaps. As it is the 190, every Luftwaffe pilot will say that's historically accurate, whether it really is, I don't know. It feels like the lift is instant when you initially deploy automatic flaps and as the Yak has better maneuverability, could make it appear to be very broken like this because you don't see these complaints with aircraft that have manual flaps. 

 

It could just be the Yak has a broken FM. I don't know.

I just know what I experience and that was a Yak barely stalling with fully deployed flaps in the straight vertical, coming out of that with speed and shooting me down.

 

In the end, something is wrong.

Edited by Y-29.Silky
  • Upvote 5

Share this post


Link to post
Share on other sites

Overall FM in BoS is very good IMO. But nothing is perfect. I think you have a point there about the flaps Silky. That looks a bit.. strange.

Share this post


Link to post
Share on other sites
It could just be the Yak has a broken FM. I don't know. I just know what I experience and that was a Yak barely stalling with fully deployed flaps in the straight vertical, coming out of that with speed and shooting me down. In the end, something is wrong.

 

Everything work as it should buddy :salute:

Edited by L3Pl4K

Share this post


Link to post
Share on other sites

I wonder, why should flaps help at all when moving in the vertical? The added lift that flaps provide should be perpendicular to the direction of flight, not just vertical. It's hard to tell on this first person video, but we should really run a recorded test and measure how far up one can travel in a vertical flight with and without flaps.

 

Also: please, please, please people refrain from making snarky remarks. There is no need to turn a technical discussion into a face-saving confrontation.

Edited by coconut

Share this post


Link to post
Share on other sites

I just did some tests. The lift vector appears to be correctly oriented (perpendicular to the flight direction). If you deploy flaps during vertical flight, you have to push the stick to keep going vertical.

 

The experiment:

  1. Quick mission, start level flight at 2000m. Minimum amount of fuel (10%, which is 40L for the yak). No ammo.
  2. activate compressor, close radiators, 100% throttle and RPM, mixture 100% (which is probably not optimal).
  3. Gentle dive to 500km/h
  4. Pull up to vertical. Try to keep this phase consistent across trials.
  5. Optionally, deploy flaps
  6. Do your best to stay vertical (not so easy)
  7. Look at altitude when you are at the top.

I did not see any significant differences between runs with flaps and runs without flaps. I ended up at about 3200m, maybe even a bit higher without flaps. I have a feeling that what you do in steps 4 and 6 weighs more on the final result.

Edited by coconut
  • Upvote 1

Share this post


Link to post
Share on other sites

Regarding the OP video: Why would a Yak not be able to pull up with full flaps if it has sufficient energy?

 

The Yak is not becoming over powered or an UFO by deploying flaps. Watch the epic ending dogfight in this video:

 

 

This fight is so long that you always know how much energy the 109 or the Yak have at any point.

I really can't see anything out of order here and the Yak pilot even knows much better when to deploy the flaps than the Yak pilot Silky faced ;)

Edited by NachtJaeger110

Share this post


Link to post
Share on other sites

According to a real Yak pilot nobody would deploy flaps in combat AT ALL, because it created so much drag. See the other thread for the original Russian quote.

  • Upvote 2

Share this post


Link to post
Share on other sites

I wonder, why should flaps help at all when moving in the vertical?

They don't. Flaps are meant to increase lift at the sacrifise in form of drag penalty (extent depends on flap construction). The further flaps are deployed the more the gradient moves towards drag than lift increasement, means that full flaps will produce more percentage of drag increase than lift increase compared to normal, undeployed condition.

 

That effect is helpfull for landing as it increases the aircrafts sink rate and allows for steeper landing approaches. In air combat however they are totally contraproductive.

 

Issues a pilot normally would encounter in a real aircraft if flying in combat with high flap angles:

- lower Critical Angle of Attack (AoA = angle between air stream and airfoil chord)

- physical stress due to G-loads threatening to a) damage the flaps mechanism (= flaps get stuck), b) rip flaps right off and/or c) damage the wing's structure

- lower stability due to shift of Cente of Lift (CoL) (might vary depending on aircraft construction + airfoil + flap mechanism)

- exposure to enemy gunfire due to the large hitting area created by extended flaps

 

Regarding the vertical flight state any use of flaps is even more idiotic to consider. In the usual case an aircraft flying vetical has no upward pointing lift vector. In both, flaps deployed and undeployed state, this means it does not gain any upward lift helping to increase climb performance. However, the drag force is still effecting the plane in the vertical counterwise to it's flightpath (in this case downward). As result the aircraft should lose speed rapidly and not gain much altitude while climbing vertical with flaps.

 

If we take the other points mentioned above int account it's very unlikely a pilot deploying full flaps in horizontal flight is able to pull the aircraft up to the vertical before stalling the aircraft and entering a vicious spin.

Edited by Stab/JG26_5tuka
  • Upvote 5

Share this post


Link to post
Share on other sites
Exacly as you wrote Stab/JG26_5tuka.

But unforatunately it is not a case in BOS.  Most pilots used flaps in Yak-1 ( i do it myself when i fly it ) beacasue it give a lot of benefis  ( better turn, more stabilized flight in vertical manouvers at slow speed which help in aiming and better gunnery solution which is unfortunately absurd in these game)

Share this post


Link to post
Share on other sites

Well said, Stuka. As flaps are lowered, the critical AoA decreases, which is the last thing you would want in a turnfight. The fact that everyone is turning with flaps down shows that something is obviosly not OK.

Share this post


Link to post
Share on other sites

 

 

I did not see any significant differences between runs with flaps and runs without flaps.

 

I did the experiment again, with the instrument panel HUD. There is a significant difference: 2300m with flaps, 2890 without. When I did the test taking the flaps out before the dive I struggled to reach 500 km/h. The 2300m were taking the flaps out while pulling up.

 

The claims that you don't lose energy when you lower the flaps in a Yak, or that flaps would provide a helicopter effect when going vertical are incorrect.

  • Upvote 5

Share this post


Link to post
Share on other sites

 The fact that everyone is turning with flaps down shows that something is obviosly not OK.

 

I only use flaps for take-off (if needed) and landing.  Could it possibly be that people use flaps because they've read about it here and think - spuriously - that they're gaining some sort of advantage?

 

After reading this thread I did some tests similar to coconut's and came to similar conclusions.  Use flaps = loose energy.

Share this post


Link to post
Share on other sites

Can we veryfiy that with flaps down the critical AoA is smaller?

 

Maybe it's a conspiracy? A rumor spread by Axis flyers? Did you know that lowering the landing gear improves the Yak's turn rate?  :ph34r:  :lol:

Share this post


Link to post
Share on other sites

 


Issues a pilot normally would encounter in a real aircraft if flying in combat with high flap angles: - lower Critical Angle of Attack (AoA = angle between air stream and airfoil chord) - physical stress due to G-loads threatening to

a) damage the flaps mechanism (= flaps get stuck),

b) rip flaps right off and/or

c) damage the wing's structure - lower stability due to shift of Cente of Lift (CoL) (might vary depending on aircraft construction + airfoil + flap mechanism) - exposure to enemy gunfire due to the large hitting area created by extended flaps

 

Some great points!

 

Would the lower Critical Angle of Attack mean that attempting some of the instant full flaps turns we see made by the Yak in BOS should instead result in snap stall tendencies?

 

If not then, what about slow speed high AOA maneuvers with full flaps - as they seem pretty stable as well?

Share this post


Link to post
Share on other sites

The Angle of Attack is the angle between the flow and the chord of the wing. The chord of the wing is the line between the leading and trailing edge. If you lower the flaps, the trailing edge goes down, giving the chord a higher angle of incidence by default. So flying level, the AoA is already increased compared to flaps up flight. On top of this, the new "shape" of the wing, cannot fly at the critical AoA of the "normal" wing, so in a word: yes. Pulling crazy maneuvers with flaps down should carry an extremely high risk of stalling out. 

Share this post


Link to post
Share on other sites

Flaps on Yak will not tear off sooner then ailerons.They are fixed to the wing very strongly,even better then ailerons.Check the drawings.

Flaps will not get "stuck" ,pneumatic system has safety valve (in fact several),check pneumatic scheme.

Share this post


Link to post
Share on other sites

I did that a while ago, there was no safety valve. Can you please show the pneumatic scheme that shows several safety valves for the flaps actuation system?

  • Upvote 1

Share this post


Link to post
Share on other sites

Nothing to add to what Reflected said, just a anecdote of my times as a midgrade flight student.

 

In one of the tests I have passed the question appeared, whether it's possible to avoid stalling the airplane by deploying flaps in a climb at critically low airspeed. As a sim pilot seing it happening often in MP and even people teaching to drop flaps during manouvres at critical speed I answered "yes".

 

Afterwards when my flight t eacher went over the test he said "No, deploying flaps is the very last thing to do in this flight state! You'd stall out imedently once you attended so.".

  • Upvote 2

Share this post


Link to post
Share on other sites

Flaps on Yak will not tear off sooner then ailerons.They are fixed to the wing very strongly,even better then ailerons.

In this case it's likely that the wing structure is taking damage under heavy stress induced by flaps under air combat conditions.

Share this post


Link to post
Share on other sites
Flaps will not get "stuck" ,pneumatic system has safety valve (in fact several),check pneumatic scheme.

 

Because hidraulic systems are very reliable, yes :rolleyes: . Just because there is a "safety valve" doesnt mean the system is immune to failures. It can and it should (!) suffer failures (being stuck is one of them) if they are operated not correctly. Something that BoS does not simulate. I know that flaps jam on the 190, but it never ever happened on the Yak...

Edited by istruba

Share this post


Link to post
Share on other sites

When the pressure of air applied on flaps surface is higher then set in pneumatic system,they will retract.

When ailerons are fully deployed,they will not damage the wing.When you pull the stick fully back,you will not tear off the tail of the plane due to elevator.


Because hidraulic systems are very reliable, yes :rolleyes: . Just because there is a "safety valve" doesnt mean the system is immune to failures. It can and it should (!) suffer failures (being stuck is one of them) if they are operated not correctly. Something that BoS does not simulate. I know that flaps jam on the 190, but it never ever happened on the Yak...

Check the pneumatic scheme of the Yak.I have nothing else to add here.

Share this post


Link to post
Share on other sites

 

Jj1klVr.png?1

 

 

 

Well, as "consolation" you can do the same thing seem in this video with Bf 109 with full flaps deployed...  :cool:  

 

They don't stall and fall of sky, just became lose speed after a while - what Yak'copter apparently don't do.  :biggrin:

Share this post


Link to post
Share on other sites

Relevant bit of Yak-1 pneumatic system - no valves. Also a sketch from Yak-9 manual - no valves. I'd be more than happy if you showed a schematic from a Yak-1 or another early version that shows the relief valves you keep mentioning.

post-627-0-33551100-1445271048_thumb.jpg

post-627-0-52302700-1445271402_thumb.jpg

  • Upvote 4

Share this post


Link to post
Share on other sites

None of those pictures is a pneumatic scheme.Technical manual of Yak-1 is available on web.

Share this post


Link to post
Share on other sites

Oh, but the left one if from the technical manual of the Yak-1 and is labelled pneumatic scheme. Put up or shut up. :)

  • Upvote 1

Share this post


Link to post
Share on other sites

if it interesting for someone, here is opinion of =MG=Dooplet11 about correctness of work of Yak-1 flaps -

 

 

"На Яке закрылки работают неверно, поэтому позволяют с успехом пользовать их при нужде в бою. .....................

 

1. Нет нейтрального положения крана. Соответственно, нет ситуации , когда нет управляющей нагрузки на штоке цилиндра щитков.

 

2. Скорость выхода щитков занижена на выпуск и сильно занижена на уборку. Неправильная зависимость скорости выхода/уборки от скорости полета. Отсюда неправильная реакция самолета на выпуск/уборку."

  • Upvote 2

Share this post


Link to post
Share on other sites

Oh, but the left one if from the technical manual of the Yak-1 and is labelled pneumatic scheme. Put up or shut up. :)

Up to 60s series there was one inbetween compressor AK-50 and filter/separator and second at the side coupling for external pressurisation of the tanks - when ac was on the ground.From 60s onward it was placed directly at pressure tank (there were 2,main with 12l volume and emergency 6l).Valve type PK-50. Technical manual page 136-141 with all schematics  ;)

Share this post


Link to post
Share on other sites

flaps will increase AoA only of the part of the wing that the flaps span. the tips remain as is and, as a result, are now at a degree of washout, which actually helps prevent tip stalling. this is why hang gliders (with fixed wing shapes) rely so heavily on the wing tips being twisted forward. the method to land the hang glider is to push the wing forward to produce a high AoA, which effectively slows the gilder and allows the wing to still fly at slower speeds (it would stall at the same AoA). the washout (forward twist)  on the tips is essential to avoid tip stalls. reason this works is because, as the wing root is pushed very close to and approaching stall, the tips are at a lower AoA and can continue to fly longer.

. thus, flaps down, should allow a wing to be less likely to tip stall than an unmodified wing.

.

another consideration is that this YAK was not "in a climb at a critically low airspeed". it was at low level flight, probably full throttle, and pulled up abruptly to meet the descending 109. it is very possible the yak deployed flaps to help initiate the climb, or to increase the rate of the the pitch change. or, he may have had them deployed already, as a low altitude may indicate loss of energy already.

.

in that OP video, i did not see anything unusual. the 109pilot was diving, which is increasing the merge rate. the yak pilot's flaps is decreasing his climb rate. we cannot really see 'how' the yak is acting in this video. all we see is that it begins to climb, with flaps down, as the 109 is diving towards it.

.

i know i've heard of actual fighter pilots, both american and german, describing the use of flaps in combat to assist in turn fights. i'm not sure if "their flaps" (combat flaps?) were that much different from the yak 1's flaps or not. i'd imagine it would be nice to deploy an adjustable amount (like the la5) rather than all-or-nothing. i certainly don't thing flaps employed at an 85deg angle (ie spitfire) or 90deg would be of any use except to slam on brakes, but flaps at 45deg (or less) would certainly be of assistance to 'lift' at slower speeds or turning radius. the yak's flaps in that video look like more of a 45deg case. if one stops the video as the yak is in the lower right glass panel of the 109, the flaps do not appear very offset from the wing at all.

.

Share this post


Link to post
Share on other sites

Up to 60s series there was one inbetween compressor AK-50 and filter/separator and second at the side coupling for external pressurisation of the tanks - when ac was on the ground.From 60s onward it was placed directly at pressure tank (there were 2,main with 12l volume and emergency 6l).Valve type PK-50. Technical manual page 136-141 with all schematics  ;)

OK, I guess I learned some Russian just now, I thought this were pressure reduction valves, but apparently they aren't. And you think that, given the lever is in flaps down position, these relief valves are directly connected to the flaps actuation cylinder? I understood that the control valve was a one way street, but don't know how I arrived at that conclusion. I'd prefer a second opinion over reproducing mine. Edited by JtD

Share this post


Link to post
Share on other sites

JtD dont worry mate, the Yak flap system is immune to failures, accordingly to Brano.  :salute:

Share this post


Link to post
Share on other sites

The Russian did because of the resistant against cold climate conditions. 

The question is why no other nation did it when it work so pretty well, because pneumatic systems was really troublesome because of leaks and malfunctions.

The answer flaps from the yak compare to the La-5 are correct what mean this? la-5 have the same wrong flap system to reality?

Still want to play the whiner about the Flaps have really good pilots (not me :)  ) with me the can overcome the flaw about the yak's in turning fights.

But when i start BOS from two months ago that was the first thing that was I noticed that feel really unrealistic a the start, have also real live flight experience.

Edited by 9./JG27MAD-MM

Share this post


Link to post
Share on other sites

Oh mine,I did not tell that it is immune to failures.Anything can break.Tubes,actuator,compressor,valves,levers,pressure tank.....Devs also stated openly that damage model of the flaps is not modelled "to the very detail".Do we realy need that? I dont think so.

 

Does someone know what was the liftime for AK-50 compressor? How much pressure could tubes withstand? For how long? Was the pressure tank sealed enough? Were valves working ok all the time?....do you have MTBF charts for this aeroplane systems? You just ask smtg that is completly out of scope of this game.You rather buy yourself real warbird,cause that wont be modelled anytime soon :P

 

 Pneumatic system in Yak,and as any other system under pressure,was equipped with valves to keep the set pressure inside.So if there was not enough pressure,valve would allow to get it thru (switching on the compressor as exp.).If there was too much pressure = in our case flaps were pushed back when deployed by airstream,it released the excessive pressure/air to maintain set value.And ofcourse air is also compressible,which adds to the effect.

 Actuator was operated 2-ways.When you want to deploy the flaps,the air was pushed inside against the bottom of the actuator,pushing it forward and letting the air in front of it to get out.When puting flaps in closed position,the air was pushed to the actuator from the inlet/outlet,which was in previous deployment step used as an outlet.

Share this post


Link to post
Share on other sites

What would you expect from Mark? He writes:

 

The Klimov M-105 P engine is one of the most beautifully designed aero engines we have ever seen, it was built to incredibly high engineering standards and is a true work of art and is exceptionally well finished.  It puts to shame many allied and axis classic engines of the 2nd World War.

 

But we all know from this forum that Yak is a plywood bucket and only devs can make her fly by tweaking the FM.

Share this post


Link to post
Share on other sites

Guys, you are barking up the wrong tree. It's not about pneumatics, systems and whatnot, it's basic aerodynamics. The more you extend the flaps the more the climb rate should decrease, as well as the critical AoA. Not to mention drag. If it was all modelled well, nobody would ever think of extending their flaps apart from landing.

Share this post


Link to post
Share on other sites

Pneumatic flaps on F4F Wildcat were used in combat all the time as 'auto flaps' it was standard procedure, as with F6 hellcat although with a slightly different system, but with same 'auto' functionality and widespread use in combat

 

Everyone (some) keep saying that the Yak full flaps don't give drag...but you don't have full flaps above landing speeds due to pneumatic operation

 

Cheers Dakpilot

Share this post


Link to post
Share on other sites

Everyone (some) keep saying that the Yak full flaps don't give drag...but you don't have full flaps above landing speeds due to pneumatic operation.

Due to developers interpretation of pneumatic operation, unproven & contradicting the manual.

Share this post


Link to post
Share on other sites

So I wrote this guy (Mark Jefferies) here: http://www.yakuk.com/aircraft-details/. I provided him with a link to this forum and my email. Maybe we will get a response from a real Yak pilot.

My bet 1$ to brainless flaps behaviour of Yak in this "game"..  :biggrin:

Edited by MK_RED13

Share this post


Link to post
Share on other sites

So I wrote this guy (Mark Jefferies) here: http://www.yakuk.com/aircraft-details/. I provided him with a link to this forum and my email. Maybe we will get a response from a real Yak pilot.

Awesome. I really hope he comes and clarifies. One way or the other and hopefully puts an end to the discussion and stupid flap behavior. No matter the plane.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...