How do they work (Russian aircraft)

[Sov13t]

As far as gear, pictures in attachment, once again 27.

[59th_LeFty]

Fair enough, I think that could be a good idea.

About unprepared orations. I guess we start with MIG-29A

Well, I understand the landing gear is more robust. F-16 main problems is the mains. When the aircraft lands the mains just spreed outboard. This causes no problems when in paved surfaces and aircraft is moving forward, tire flexes and take the train on this. But in the dirt it would just dig in. Obviously landing gear is not that big nether ( even on later blocks) My main question is, can they take off with a full load of weapons? If not what are the weight limitations? Does it have to be on grass?

 

I'm quite sure that the Fulcrum is not designed to operate from grass fields, the MiG-21, and maybe the 23 were intended to do so. But I wouldn't be surprised if the Fulcrum is able to do it also. Well, at least once :D

About the strake intakes for MIG-29

Are those things spring loaded?

I remember seeing a video of a MIG-29 flying at low speed and you can see the strake intake flapping, let me see if I can find that

 

Sorry I know I'm all over the place, I did not lie when I said I had a lot of questions :D

Yup', they are spring operated. If you forget about them walking on the plane, you can easily have a bad day :) The shaft can be sealed from the intake when on the ground. About the intake doors, they have two basic functions, the ones described above, to avoid sucking in objects from the ground, and also working to drive the airstream which is required for supersonic flight. You can find graphics about t in the MiG-29-GAF manual.

 

As for the power sources, the MiG-29 has internal batteries for startup, as nscode said external AC is only preferred more. The reason is, that the generators can not charge the batteries... dunno why. Or dunno why didn't they put such batteries into it.

The onboard systems has a generator of 3-phase (3x36V) 115V 400Hz AC to power hyraulics and other power-hungry systems, and a 28V DC which is also responsible for APU startup, and acts as emergency power source.

[zakobi]

Not to derail, but this makes me think: how much can the A-10's gear take? I know there's something with a little part of the wheels not fully retracted as of emergency landing.

[mvsgas]

Not to derail, but this makes me think: how much can the A-10's gear take? I know there's something with a little part of the wheels not fully retracted as of emergency landing.

 

Not sure, I do not think it could take off fully loaded nether, you wouldn't have to, but I'm sure if it had to operate from dirt fields, only limited weapons and fuel load would be use. They posted the manual on A-10 in the forums, I will look it to it after the MIG-29 manual. I'm sure one you guys would find this before me. :joystick:

[mvsgas]

Every time I see or learn somethings I get more question, it's a vicious cycle I guess.

 

The wire coming from the bottom of the gear itself and touching the ground, that is the grounding wire correct? I bet they have to replace those all the time. We just use grounding wires, which are installed when and aircraft is parked.

 

Like I ask before, why only one chock? We normally use two per main tire, some places require one pair for the nose tire as well.

 

There is very little tread left on that tire for that much snow on the ground, normally we have different tire wear requirements ( wet and dry weather)

 

:thumbup:

Edited August 18, 2010 by mvsgas

[Groove]

It seems like they use "both" methods mvsgas:

 

[Fahhh]

The reason is, that the generators can not charge the batteries... dunno why.

 

The manual says that the batteries require higher recharge voltage than the generator is able to provide, and thus it cannot be used for this...

 

Another fact is that the fulcrum holds a huge advantage over previous russian birds in the relatively easier maintenance and access to aircraft systems. Replacing an engine in the Fulcrum by a well prepared team should not exceed few hours, while in the MiG-21 for example at least a day is required. The engines however have always been problematic. While they perform very well in the air(apart from smoking too much :P ) their life is short, and require frequent maintenance. That is why they are often tuned down by a further 5-10% in thrust in exchange for longer lifespan.

[JLZ]

As for the power sources, the MiG-29 has internal batteries for startup, as nscode said external AC is only preferred more. The reason is, that the generators can not charge the batteries... dunno why. Or dunno why didn't they put such batteries into it.

 

Since the charging voltage of the silver-zinc batteries is higher than the generator voltage, the batteries will not be charged when the generator power is available.

As far as I read, there is no AC/DC converter but DC/AC PTO only for case if AC generator failed.

 

In case of DC generator failure there are batteries. That's way is important to keep them fully charged...

 

EDIT: Man, I'm always late...

[mikoyan]

Here are my questions!

So... what happens on the mig and su-27 when you loose an engine or both? do you loose power to the controls in a double engine flameout? I read that on the f-18 one of the engines provide power to the flight control system and if you loose it you loose control of the airplane? was that the case with the f-18 that crashed on San Diego? The report says that one of the engines was malfunctioning due to a fuel line problem and when the pilot was close the the base the other engine quit and he had no control after that.

Why most of the russian cockpits are painted blue? (the mig-35 has a dark cockpit way cooler to me)

What is the start up procedure for the su-27?

What happens after you pull to much (going slow) and override the stick bumper or pusher on the mig-29, does the airplane drops one of its wings violently like you can expect form a regular swept wing aircraft or it drops gently?

Is it possible to enter a flat spin on the f-16 or a wing rock? there is a report of an accident on wich an f-16 loaded with a ventral fuel tank crashed because the pilot lost control wile pulling to much and the airplane stalled and crashed into the sea, if that is the case; I tough that the f-16 flight control system would not allow you to get into spins.

[GGTharos]

The FCS helps you stay out of trouble, but it doesn't completely prevent it.

[Sov13t]

Believe it or not, light blue color of the Sukhoi cockpits is due to psychological study that blue promotes peace/relaxation and makes the cockpit feel more spacious than it really is. There is an institute in Russia that is responsible for ergonomics/layout of cockpits and other medical/human related things inside of airplanes.

 

Saw a small skit on it in one of the shows a while back, no sources beyond that. MiG's try to be different from Sukhoi ;) Little competition they got going.

Edited August 18, 2010 by Sov13t

[mikoyan]

mmm; maybe that is why I like to fly the su-27 more than the american jets in lock-on!

[JLZ]

Here are my questions!

So... what happens on the mig and su-27 when you loose an engine or both? do you loose power to the controls in a double engine flameout?

 

You have accessory gearbox which is responsible for driving all accessories. That gearbox is connected to engine gearbox(es) via clutch(es). By Default right side engine is connected for driving accessories gearbox. If there is 8% RPM more on left side engine then aircraft engages LS engine for driving accessory gearbox.

If you loose RPM on one engine, control and power systems continue to work. If you loose both engines you loose all accessories driving power (except battery driven ones).

 

I think that without hydrolics it is very hard if not impossible to maintain control of aircraft and/or land it. If you can't or doesn't have a time to restart engines there is only one solution: eject.

[IvanK]

" Believe it or not, light blue color of the Sukhoi cockpits is due to psychological study that blue promotes peace/relaxation and makes the cockpit feel more spacious than it really is."

 

Boeing came to the same conclusion for its modern airliner cockpits but decided on BabySh.t Brown !

[zakobi]

" Believe it or not, light blue color of the Sukhoi cockpits is due to psychological study that blue promotes peace/relaxation and makes the cockpit feel more spacious than it really is."

 

Boeing came to the same conclusion for its modern airliner cockpits but decided on BabySh.t Brown !

 

:megalol:

[EtherealN]

I think that without hydrolics it is very hard if not impossible to maintain control of aircraft and/or land it. If you can't or doesn't have a time to restart engines there is only one solution: eject.

 

I haven't looked at the Flanker's hydraulic layout, but I would assume that you'll be fine for at least a moment running your hydraulic actuators on acc pressure. Being economic with your control movements obviously becomes extremely important in such a case though, and I've really got no clue whether it would be in anything but really rare conditions that you might have enough pressure left in the accs to safely land.

 

I guess it might be at the level where acc pressure is enough to let you point the aircraft in a safe direction before ejecting.

[bumfire]

" Believe it or not, light blue color of the Sukhoi cockpits is due to psychological study that blue promotes peace/relaxation and makes the cockpit feel more spacious than it really is."

 

Boeing came to the same conclusion for its modern airliner cockpits but decided on BabySh.t Brown !

 

lol :lol:

[Boberro]

" Believe it or not, light blue color of the Sukhoi cockpits is due to psychological study that blue promotes peace/relaxation and makes the cockpit feel more spacious than it really is."

 

Boeing came to the same conclusion for its modern airliner cockpits but decided on BabySh.t Brown !

 

Many times I've been thinking about cockpit color... for me that blue is gayish. Grey is better IMHO (more quiet).

[mvsgas]

Thank for the info, That was going to be my next question Hydraulics. Using the F-16 and F-117 as sample since well I only work on them two.

 

So... what happens on the mig and su-27 when you loose an engine or both?

That is a very good question... but are you asking about Hydraulic power or electrical power?

I'm wondering about hydraulics, how are they structure or designed? How many pumps? At what pressure do they operate?

 

For comparison, on the F-16, there are 3 pumps, two main ones that provide pressure to flight controls and one of the main pumps also provides pressure for things that are not really required for flight ( gun spin, landing gear extension, etc) Everything has a back up. The last pump is emergency and will provide hydraulics pressure even if the engine is out or off.

 

F-117 had 4 main pump and one emergency.

Is it possible to enter a flat spin on the f-16 or a wing rock?

Yes, there is a video on you tube where you can see and F-16 depart flight

it has been posted here several time I think ...

The DFLCC/FLCC will do every in can to stabilize the aircraft but i will not prevent bad pilot inputs and aircraft still susceptible to aerodynamics.

[mvsgas]

I wish I can rep you guys more thanks for the insight.

EtherealN, Do you have the flanker hydraulic lay out? Would it be possible to share with us?

Edited August 19, 2010 by mvsgas

[JLZ]

I haven't looked at the Flanker's hydraulic layout, but I would assume that you'll be fine for at least a moment running your hydraulic actuators on acc pressure. Being economic with your control movements obviously becomes extremely important in such a case though, and I've really got no clue whether it would be in anything but really rare conditions that you might have enough pressure left in the accs to safely land.

 

I guess it might be at the level where acc pressure is enough to let you point the aircraft in a safe direction before ejecting.

 

AFAIK hydraulic doesn't accumulate pressure as pneumatic does. Accumulated energy in oil transfers through heat into fuel (which is deliberately used as oil cooling medium) so you need pump to "inject' energy into oil (pressurize it) back.

(I'm sorry if I missed some concept. Correct me please)

 

Anyway, emergency topic is on 200th page of MiG29 manual. I read it now but maybe I excluded some more info.

 

To make it short:

Both engine flameout - If neither engine relights passing 6 500 ft AGL, an immediate ejection is recommended.

 

29's have Main and Boost hydraulics and Emergency one (They operate at P from 19Mpa to 22MPa). With Emergency one, only severely degraded aircraft controllability is available (Emergency one operate at P up to 24MPa but with limited delivery rate output).

If you regain one hydraulic system - Prepare controlled ejection

If you lost all hydraulic pressure - Throttles OFF, Eject

 

These were procedures from flight manual.

 

mvsgas, what is driving that emergency pump (the last) one? I doubt there is enough battery power on aircraft for it's prolonged operation.

[mvsgas]

mvsgas, what is driving that emergency pump (the last) one? I doubt there is enough battery power on aircraft for it's prolonged operation.

With the engine off, Hydrazine and I'm not talking JAVA, :D

http://www.f-16.net/f-16_forum_viewtopic-t-1056-postdays-0-postorder-asc.html

Edited August 19, 2010 by mvsgas

[mvsgas]

What powers the MIG-29 emergency pump? ... Oh I almost forgot I got the manual to :book:

[AlphaOneSix]

AFAIK hydraulic doesn't accumulate pressure as pneumatic does.

 

True, liquids are not compressible (or at least, in relation to gases, compress so little as to be useless in the context of this discussion).

 

However, pretty much all hydraulic systems on aircraft incorporate some kind of accumulator system to either dampen or store hydraulic pressure. In many cases, this is done by forcing hydrualic fluid into a chamber that contains a gas-filled bladder. Liquid entering the chamber compresses the bladder and the gas within it (usually nitrogen). If the normal hydraulic pressure system (the pump) fails, the compressed bladder will force the hydraulic fluid into the system for a short period of time (until the bladder expands fully into the chamber).

[mvsgas]

AFAIK hydraulic doesn't accumulate pressure as pneumatic does. Accumulated energy in oil transfers through heat into fuel (which is deliberately used as oil cooling medium) so you need pump to "inject' energy into oil (pressurize it) back.

(I'm sorry if I missed some concept. Correct me please)

This sentence is confusing to me, I have been trying to make since of it. Maybe we lost something in translation. You talk about both pressure and temperature.

Hydraulic systems and fluid do heat up due to compression but pressure are normally regulated to stay about the same (what ever pressure the aircraft needs) so temperature has little effect on pressure ( within the context of aircraft hydraulics I work with, obviously thermodynamics apply to fluids all the time and affects their characteristics) ... :joystick: I think I just confuse myself :noexpression::D