Engine vibration in 3 minutes of dust - why?

[VS461]

Hi girls and guys,

 

I made a training run based upon a custom LOFC mission called Valley of Death (remember when you had to run through canyon-like valleys in an A-10 to mess with some Smerch launchers, and when you're back to Sukhumi, it's occupied by a Tor, a Shilka and a Strela-10. Never was able to get rid of all of them:music_whistling:).

 

It's easier to stalk close with a Ka-50, so finally I can destroy the GBAD, but last time I just closed in at 3-4 m and about 30 kph, and suddenly Rita said it's vibration in the engine and the right one slowed down to idle (I think both had vibration but didn't remember). After the emer landing (well, I found myself on the ground with broken gears and blades...:D), the right one was in flames, and after ten secs she exploded although I had initialized the fire ext'er.

 

I don't know why I had vibration: I didn't set failures. I found on ED forums that dust or ice can cause vibration and I didn't turn on the PZUs. Both icing and dust can cause engine stops, pressure oscillation (don't know the English term for it), and dust can cause the compressor blades' increased wear, reduced pressure ratio, EGT and performance. But in such a sort period of time (3-4 mins)? It must be hours of hard dusty or sandy operation to happen this last thing (you know, the Russian steel :)).

 

And vibration? I can imagine that dust wear can unbalance the compressor blades but it shouldn't cause longitudinal vibration; TV3-117's IV-500E (if Ka-50s have this type; Mi-24s do have) vibration check unit detects only this longitudinal ones (for example, at both engines' vibration at same time you should suspect main gearbox failure and land ASAP).

 

So, I don't know if this is an IRL stuff, although I haven't spent hours and hours in dusty and sandy areas with TV3-117s. Yet...:noexpression:

 

Any ideas or arguments?

Cheers!

 

PS: Any A-10 jock who completed Valley of Death in LOFC: how can I get rid of these air defense guys, particularly the Tor stuff :) ?

Edited September 16, 2009 by VS461
unspecifying

[Laud]

Let the Tor shoot at you, then turn ECM on and turn beam or cold (depends on your distance, normally you can beam, return head on again and then turn cold. So two missiles spoofed per approach). Watch the missile explode. Repeat until it's empty. -> KILL IT!

 

:)

[159th_Viper]

Another approach is to Draw the first launch at RMAX and toggle ECM on/off. Take note of the radius and fly a lazy circle just in RMAX but further than the TOR Kill-Zone, toggling ECM as you go. Count 8 Self-Destructs, Land and cap him with your 9MM Service Pistol :D

[Laud]

But for circles you need a safe area around/behind the TOR!

 

Killing him with your Beretta - priceless... :)

[Sarge55]

Have to ask. "Turn cold" is a new phrase for me. What does it mean?

[TKMR]

Another approach is to Draw the first launch at RMAX and toggle ECM on/off. Take note of the radius and fly a lazy circle just in RMAX but further than the TOR Kill-Zone, toggling ECM as you go. Count 8 Self-Destructs, Land and cap him with your 9MM Service Pistol :D

 

Win.

Damnit. Already gave you rep somewhere else. =(

 

Aim for it, and eject? XD

[159th_Viper]

Have to ask. "Turn cold" is a new phrase for me. What does it mean?

 

Turn 180 degrees and extend out of the Engagement Zone.

[VS461]

Hi,

 

seems the thread doesn't reach its original goal :D.

 

Thanks for the A-10 jocks anyway, I'll try it ASAP :thumbup:.

 

Cheers!

[AlphaOneSix]

I don't have any proof, but I do get the feeling that in the game, the effects of staying in the dust too long without your PZUs running is exaggerated. I don't particularly mind because it's a good reminder to use the PZUs down low.

 

I'm pretty sure all TV3-117s come with the IV-500E, we have them on our Mi-17s as well.

[VS461]

I don't have any proof...

 

Well, you're right. I should ask for lifetime wear modelling as well... periodic maintenance... 25 hours check... rotor blades on cone... :D (I won't!).

 

Just curious about this vibe issue...

 

Cheers!

[AlphaOneSix]

pressure oscillation (don't know the English term for it)

 

If this is what I'm thinking of, we call the oscillations "surges" and we commonly have issues with surging on older engines. We use the term specifically when referring to oscillations in Ngg RPM.

[TKMR]

Have you done any tests to reproduce?

 

eg Find an empty field, get down low, and hover in the dust. See how long it takes. I would think it would take a couple hours, but what do I know.

[Bulletstop]

When you are in the dust, isn't there a dust filter switch? I thought I read you should engage them while in the dust. If I remember it cause the engine to run hotter?

 

Bullet

[miguez]

When you are in the dust, isn't there a dust filter switch? I thought I read you should engage them while in the dust. If I remember it cause the engine to run hotter?

 

Bullet

 

Hi Bullet,

 

Extended English manual, page 6-43, "Engines de-icing/dust-protection systems switch". It's on the right side of the overhead panel, and it is a three-position switch. Middle is off, Up is de-icing, down is dust-protection.

 

And yes, when either de-icing or dust protection are on you'll see a rise in EGT.

[VS461]

Hey guys,

 

I cannot reproduce this thing, although I spent twice or threece (OK, language reform off, three times:D) the flight time in loads of dust at near hover but didn't happen. I will work on it, in the same mission.

 

Miguez, Bulletstop, you're right. Both engine de-icing and PZUs (dust separators) drains air from the compressor (can't remember from which stage), so if you switch them on, to maintain the same drag on the rotor, EGT must be increased a bit to spin up the engine (the compressor), to draw the plus necessary airflow.

 

Cheers!

[Bulletstop]

Ah I thought I had read it, thanks and now when I am inb to a grassy area I will switch it on. Thanks for the reply :)

 

Bullet

[AlphaOneSix]

drains air from the compressor (can't remember from which stage)

 

Actually comes form the combustion section. :)

[VS461]

Actually comes form the combustion section. :)

 

:poster_oops:

 

Well, seems I should re-read some technical stuff... to be on holiday week after week...:D. Thanks!

 

Btw... to the PZU either?

[AlphaOneSix]

:poster_oops:

 

Well, seems I should re-read some technical stuff... to be on holiday week after week...:D. Thanks!

 

Btw... to the PZU either?

 

Yep, the same pipe that feeds anti-ice also feeds the PZU.

[26-J39]

Reading this thread i became curious.. I tried the experiment, hovered about 1-2m above the ground and tried to slowly move backwards as to not let the dust escape the intakes, anti-dust off.. Have an engine vibration and crash :doh: after only about 15minutes ;)

I included the TRK.. Cheers

26-J39-ENG-VIB-NO-ANTIDUST.trk

[RvETito]

The compressor deterioration by dust is made such on purpose for gameplay reasons- to avoid people flying unrealisticaly in the RIG zone all the time. No real pilot does that exactly because the dust affects powerplant's performance in long term.

 

Not 100% sure but I doubt that the Ka-50 is equipped with IV-500E vibration monitoring system. It rather has IV-79P-V-2 but functionality is similar- one sensor on the each engine's forward mount.