Trying to break the engine

[NakedSquirrel]

I've been trying to find the engine limits of the P51 to include in a tutorial, but when I finally sat down to test the limits, I can't find any?

 

I wanted to test the engine at different throttle and RPM settings, but even on the deck through the gate (WEP) the engine lasted over half an hour (I ran out of fuel before the engine would break). I didn't think to take drop tanks or fill the fuselage tanks for these tests since I was going for "combat power". I thought it might have been something to do with the mission settings, so I went on a MP server and I found the same thing... I had my engine seize once during the MP session after 20 minutes of flying 67 manifold and 30 rpm. Then I thought perhaps it was because I was constantly over 300mph so I tried doing stalls and dropping flaps... my temperature went up, but my engine kept running. The second time, while stalling and flying at 100mph, the engine finally slowly quit after about 5 minutes of slow aerobatics. Surprisingly, it didn't seize up right away, it slowly died after sitting at 150+ degrees for 2 minutes.

 

Am I missing something?

 

Did Spinaltap tweak my P51?

 

Edited January 18, 2015 by NakedSquirrel

[sobek]

Are you sure you are flying in simulation mode with damage enabled?

[Exorcet]

For me the P-51 is pretty sensitive unless I manually open all the cooling. Then again I haven't done a stress test in a while so maybe the limits went up and I didn't notice.

[BFBunny]

cold start, roll to runway, rpm to max, slam throttle to max. Engine bang.

[PLP]

If I remember well another way to damage the plane is low rpm high manifold, although this does not kill the engine per se. As stated above full power low airspeed after takeoff does kill the engine in under 5' IIRC. Flying on a server changes the settings only if the hosted mission forces said setting, which is not automatic.

[Winston60]

P-51 engine damage model is porked in multiplayer. May have something to do with the high oil pressure bug. Some patches back I could fly 1 hour plus at the "all day" setting of 46 inches and 2700 rpm, but now I get random engine seizures at that setting.

 

ED is aware of this oil pressure bug. Once it's fixed hopefully engine reliability and the "all day" engine setting will return.

[Art-J]

The last time I tried killing the engine on purpose was in the 1.2.8 era. Running WEP with radiator closed manually was good enough to roast it in under 2 minutes, any other overheating scenarios were doing it slower, but apart from that, the engine was rather impossible to kill. I tried overboosting with all sorts of combinations of RPM and MAP, also with cold oil, yet the Merlin was ticking as if noting happened. A bit disappointing :D.

 

Don't know how much has changed since then, but I'd rather wait till the current oil bug is fixed before repeating similar tests.

[Solty]

You can kill your engine when going very steep vertical climbs easily. The manual says things that you should do because it shortens the engine life but in reality you can fly on high mp and rpm for very long time. Always look at the temperatures. You don't want to overheat.

[313_Nevo]

cold start, roll to runway, rpm to max, slam throttle to max. Engine bang.

how long is this implemented?

[Anatoli-Kagari9]

I recall we had some problem here, but at least as of the last release, which I do not think listed anything regarding the p51d, I do have to be careful with my engine management.

 

Even flying to my objectives, and while cruising, if I forget to get those temps within limits, I am up to a ditch somewhere, most of the time too close to the enemy line :-/

 

My only complaint is regarding damage inflicted to the engine. 99,99% my prop is jammed by Flak, and I lose control of the RPMs... And it's always the same ? Strange their precise aim and the way DM is modeled regarding it...

[BFBunny]

how long is this implemented?

 

Had a bit of a frustrating 15 min trying to make it do this again. Eventually managed to get it to pop after putting the temp to -40 and climbing straight off the runway down the dirt. It took a minute or so.

 

I recall it popped the engine after doing a full power acceleration on grass in my earlier reply, but maybe I had been flying a while before. Seems like you can full power it even taking off on the grass, but it refuses to start if the outside temp is 50 degrees. I feel like I've blown it before a number of times when I only had the free tf51 version and could not fly it seemed to explode a lot more and this full power issue seemed to happen more often.

 

Seems to go on forever if you keep the temp down. You can max power energy fight for ages as the heat you make going up is lost on the way down.

 

Maybe I just assumed if you red lined the rpm and manifold pressure it would self destruct so I never really have.

 

Although I started the 109 in the air, turned on the mw50, straight to max power, few seconds later it was a glider. That was new!

[Crumpp]

My only complaint is regarding damage inflicted to the engine. 99,99% my prop is jammed by Flak, and I lose control of the RPMs... And it's always the same ? Strange their precise aim and the way DM is modeled regarding it...

 

I was on the DoW server the other day. Cold start, beautiful take off, got everything set and babying the engine in nice climb to altitude (15,000 ft) and cruise to the target area. Monitoring and pushing checklist just like when flying in RL.

 

Get over the target area and spot tracer fire along the ground. Just as I turned to investigate a big burst of flak goes off right next to my left wing. The aileron is missing and the plane looks like swiss cheese. Took out my hydraulics and I ended up bellying in after limping back home. 30 minutes wasted just to cost my team points for trashing the plane!

 

:mad:

 

Wish I had that Flak gunners luck and a lottery ticket! :P

[Art-J]

My only complaint is regarding damage inflicted to the engine. 99,99% my prop is jammed by Flak, and I lose control of the RPMs... And it's always the same ?

 

The "Porcelain Prop Governor" ghost, known from P-51s in good ole' Il-2 Sturmovik series, is haunting us in DCS P-51 as well :D. We gonna need programmer with strong exorcism skills to make it go away!

[julian265]

The "Porcelain Prop Governor" ghost, known from P-51s in good ole' Il-2 Sturmovik series, is haunting us in DCS P-51 as well :D. We gonna need programmer with strong exorcism skills to make it go away!

I thought the same thing :( It seems too common.

[NakedSquirrel]

Well I know the engine breaks if it gets hit by flak or shot. That is kind of given. I've read ED plans on improving the DM of their aircraft, especially the visual side of things sometime after EDGE (ETA 2 weeks of coarse)

 

I'm just asking if the internal wear and tear is modeled with these recent patches? I tested using my own mission in the mission editor, then decided maybe it was my mission settings and went to the "landing" final approach" instant action mission. I was able to do whatever I wanted with my throttle and pitch settings, the engine continued to run until it ran out of fuel. Same happened when I tried a MP server.

 

I remember being able to break it before if I ran at 61mp 3000rpm for 10-15 minutes. Using WEP, The engine would quickly break, but I never timed it. I always assumed it was 5 minutes (per page 30 in the AC manual) I used to be able to keep the engine going for about 1/2 an hour if I ran at 60 manifold and 3000RPM, but now those precautions don't matter? I can run full 67 MP and 30rpm without any worries at the moment.

 

Is there something in progress with the Mustang? I didn't see anything about the P51 in any patch notes, I didn't know the engine values were being tweaked?

[Solty]

The "Porcelain Prop Governor" ghost, known from P-51s in good ole' Il-2 Sturmovik series, is haunting us in DCS P-51 as well :D. We gonna need programmer with strong exorcism skills to make it go away!

 

It is almost as (in)famous as the 190 bar.

 

Well I know the engine breaks if it gets hit by flak or shot. That is kind of given. I've read ED plans on improving the DM of their aircraft, especially the visual side of things sometime after EDGE (ETA 2 weeks of coarse)

 

I'm just asking if the internal wear and tear is modeled with these recent patches? I tested using my own mission in the mission editor, then decided maybe it was my mission settings and went to the "landing" final approach" instant action mission. I was able to do whatever I wanted with my throttle and pitch settings, the engine continued to run until it ran out of fuel. Same happened when I tried a MP server.

 

I remember being able to break it before if I ran at 61mp 3000rpm for 10-15 minutes. Using WEP, The engine would quickly break, but I never timed it. I always assumed it was 5 minutes (per page 30 in the AC manual) I used to be able to keep the engine going for about 1/2 an hour if I ran at 60 manifold and 3000RPM, but now those precautions don't matter? I can run full 67 MP and 30rpm without any worries at the moment.

 

Is there something in progress with the Mustang? I didn't see anything about the P51 in any patch notes, I didn't know the engine values were being tweaked?

 

That is normal. The engine on any of the planes wouldn't "die" after 10min of using WEP. If you are flying level the engine can take a lot of abuse. The numbers in the manual are there to prolong the engine's life, so that pilot's wouldn't overstress it and it could serve longer without replacement of the whole thing. Of course it depends how much you can push the engine, on a lot of factors like humidity or temerature, pressure etc. But the engine can realy keep on going. If realy big abuse is given to the engine it will start to loose power and some issues may occur, but not immediately after few minutes.

Edited January 20, 2015 by Solty

[313_Nevo]

BFBunny I am asking because exactly the same thing happened to me during MP session after the last patch and I didnt notice it before patch. I am just wondering if it was some random failure or I was too rough to the engine.

Didnt have time to test it again :)

 

the other thing is this

Do not use HOT AIR at altitudes above 12,000 ft. Doing so may affect the carburetor's altitude compensation and result in an overly lean fuel mixture.

is this modeled? does it really 'affects the carburetor's altitude compensation'?

Edited January 20, 2015 by 313_Nevo

[Crumpp]

The "Porcelain Prop Governor" ghost

 

Part of this is the location of the governor and how our propellers work on the P-51.

 

In the Hamilton Standard, the governor, dome, and mounting pad fill the space of the "chin" between the carburetor intake and spinner. Kind of hangs out there begging to be shot if you take damage to the nose of the aircraft.

 

That big dome on the Hamilton Standard propeller front is filled with oil that the governor regulates the pressure and houses the mechanism that changes the propeller blade angle.

 

Here is the Hamilton Standard:

 

 

 

 

The Aeroproducts is a little better protected, it not only has an adapter assembly that fits on the Hamilton Standard governor pad to bring oil to its governor, the Aeroproducts Propeller governor is the pretty much the propeller back plate for the Aeroproducts prop.

 

It gets rid of the big oil filled dome out front of the Hamilton Standard and tries to hide some of it behind the propeller hub assembly.

 

 

 

 

[Solty]

The only problem is that I always loose the governor when my enemy is shooting from m six o clock-.-

[Crumpp]

The only problem is that I always loose the governor when my enemy is shooting from m six o clock-.-

__________________

 

Yep, things that make you go....

 

:doh:

 

I think the damage model is already on the list for the devs.

[Crumpp]

The numbers in the manual are there to prolong the engine's life, so that pilot's wouldn't overstress it and it could serve longer without replacement of the whole thing.

 

Depends on the settings. Anything at 100% and below, I would agree that the main purpose is best performance including engine life. Engine ratings above 100% design capacity I would disagree.

 

You fly around in any engine above the 100% capacity, you are risking an immediate and catastrophic failure. The limit is designed to avoid that immediate and catastrophic failure. Engine life is secondary as the rating is for emergency use only anyway.

 

Here is the RAF's General Pilot's Notes on engine limitations and why they are in place:

 

 

The P-51 Operators Manual also mirrors the warnings of immediate breakdown.

 

 

Here is a quick look at all the design changes necessary to the Merlin engine series to make +18lbs (67inHg) for 5 minutes acceptable reliability to avoid that immediate breakdown.

 

 

 

That being said, these ratings do greatly reduce the engine life which is why these highly over-boosted ratings well above 100% required logging of times and inspections.

 

Here is the inspections the P-51 Operating Instructions call for:

 

 

 

[Friedrich-4B]

That being said, these ratings do greatly reduce the engine life which is why these highly over-boosted ratings well above 100% required logging of times and inspections.

 

Here is the inspections the P-51 Operating Instructions call for:

 

 

 

Note: the entire section, including the section titled AIRPLANE, describes the standard inspection made after each flight, regardless of an 'emergency' or the use of WEP. (NB: These extracts are from the P-51D/K Maintenance and Erection Manual)

Edited January 21, 2015 by Friedrich-4/B

[NeilWillis]

I have found ploughing the plane into the ground does considerably more damage to the engine than trying to destroy it by pushing the limits. I guess we need to have cumulative damage modelling, so that if you abuse the engine on one flight, it'll be carried over to the next, and eventually the engine will give up on you when you need it most.

 

Just don't assume that they'll go bang just because you exceed the operational limits. The damage will be done, and the life of the engine compromised, but there are always safety margins, and they may not be visible within the duration of the flight. Is it fair to expect that to be modelled?

 

Instead of trying to test the limits of the plane, why not test your own limits, and expand your abilities instead?

[Solty]

I have found ploughing the plane into the ground does considerably more damage to the engine than trying to destroy it by pushing the limits. I guess we need to have cumulative damage modelling, so that if you abuse the engine on one flight, it'll be carried over to the next, and eventually the engine will give up on you when you need it most.

 

Just don't assume that they'll go bang just because you exceed the operational limits. The damage will be done, and the life of the engine compromised, but there are always safety margins, and they may not be visible within the duration of the flight. Is it fair to expect that to be modelled?

 

Instead of trying to test the limits of the plane, why not test your own limits, and expand your abilities instead?

That is a lot of work and makes no sense when during MP missons as we can always respawn and there is option to repair the plane on the ground. This would be just additional weight on the Devs and we have many more real problems with the sim. Additionaly. If the engine was too damaged, the ground crew would repair it. It is not the pilot's problem at that point. And if it was damaged beyond repair, they would just change the engine.

 

We have combat sim here, not a civilian one. You are not a owner of an old plane from 1944 in 2015. You are a pilot during 1944 (or rather 1945 period) and you have your ground crew.

[Crumpp]

ote: the section titled AIRPLANE describes the standard inspection made after each flight, regardless of an 'emergency' or the use of WEP.

__________________

 

No, that is actually in the next section..daily inspections.