behavior of the Mustang while hard flying

I was flying along, and decided I would yank the stick, up and down, back and forth, not violently, but not smooth. I wasn't going full speed at all, probably 80 %. All gauges below red. On left fuel tank. Plenty of fuel in the tanks. 10k feet altitude. As I took the stick, up down back forth, not full, just enough to toss the plane, the Mustang lost power, lost speed, acted fuel starved, took a minute to recover rpm, speed, etc,, I dropped some altitude, leveled out, held steady, all was back to normal. I have never seen this happen before with the Mustang, in any sim I fly. it clearly acted like I was in a violent situation, but I was just throwing around a bit, but not much, and not upside down at all. :joystick:

Not upside down doesn't mean you didn't accumulated big negative G's, isn't it? I don't remember how long could P-51 fly inverted, but I don't think that's a very long time, provided you accumulated enough negative G's you left engine starved. IIRC also fuel movement inside tanks were modelled, also may be you managed to get fuel pumps working dry.

S!

I get it. It's just my opinion (and a ton of on line fliers on TS), but E.D. sold this plane short. I never use it for anything but single player ground attack. Anything else is just suicide.

It's fun to fly, but not in any situation where you have to push it. It's pretty useless at that point. Power problems, maneuverability issues a lot of the time. And after watching some others do it, I can only get this plane up to 20,000 ft. about 50% of the time. I would gladly post track of this problem if only ED would fix the Track issues. Every time I record it and look at the track, the plane just goes into the ground or whatever, I gave up on actually trying to make this module act like everything I have seen or read about the P-51.

I have been pretty happy with almost everything about DCS to this point. The P-51 however has been a major disappointment for me. Some others seem to have better experience with it.

Regards the getting to 20k ft are you ensuring your mixture is in the RUN rather than EMERGENCY RICH setting?

Yep, seems like someone flies with emergency rich. P51D has two stage two speed supercharger, you need to remember that between 10.000ft and 15.000ft it will loose power and until the second gear starts to work it will feel sluggish.

I basically think you may have broken something with your radical maneuvers :joystick:

The manual says a maximum of 10 seconds of inverted flight, but this is because ".. the oil pressure falls off, because no oil reaches the scavenger pump. For this reason, inverted flight must be limited to 10 seconds".

The Packard V1650-7 Merlin engine has, from my understanding, a Skinners Union Speed-Density carburetor, which is not affected by gravity at all, so beyond the reference to the oil pump, I don't believe there should be any affect from radical maneuvers, beyond air sickness :D

Edit: Dangit Solty, bustin' in there 10 minutes before me :lol:

Hard to tell, because the felt loss of power could be quite subjective. But yes, if you expect to accelerate at 10k the same as at 5k, you might easily register that.

I basically think you may have broken something with your radical maneuvers :joystick:

 

The manual says a maximum of 10 seconds of inverted flight, but this is because ".. the oil pressure falls off, because no oil reaches the scavenger pump. For this reason, inverted flight must be limited to 10 seconds".

 

The Packard V1650-7 Merlin engine has, from my understanding, a Skinners Union Speed-Density carburetor, which is not affected by gravity at all, so beyond the reference to the oil pump, I don't believe there should be any affect from radical maneuvers, beyond air sickness :D

 

Edit: Dangit Solty, bustin' in there 10 minutes before me :lol:

 

Hard to tell, because the felt loss of power could be quite subjective. But yes, if you expect to accelerate at 10k the same as at 5k, you might easily register that.

auf den Kopf gar nicht fliegen

I was not upside down at all

:doh:

No, lol, but before the SU carb and before the Tilly Orifice, the Merlin would stall if you nosed down quickly, because the carb float would flood the float chamber. When the negative G's abated, the over-filled float chamber would flood the engine. I remembered reading the 10 second rule in the manual, so I looked it up again and posted my findings.

The Tilly Orifice prevented the over-fill from flowing out quicker than the engine could use it, which prevented the flooding. That was were my thoughts were. So I did some research and found that the V-1650-7 Packard Merlin had the SU carburetor, which did not use a float chamber at all. Fuel flow was always in positive pressure and injected into the manifold. Flow was controlled through the mixture control, throttle, supercharged air pressure and temperatures and various other pressure and temperature measurements.

So basically, unless broken, you should be able to put the V-1650-7 Merlin through any attitude change, the P-51D could handle, without any performance degradation.

I still have some questions as to what actually happened. You said you were at 80% full speed. That would be about 330 AIS, considering 415 at sea level being considered max speed in level flight, which is pretty fast for level flight. What RPM and MP setting/readings did you have before you started the radical maneuvers?

You stated, "the Mustang lost power, lost speed, acted fuel starved, took a minute to recover rpm, speed". RPM is controlled by the prop governor, and unless you reduce manifold pressure far below 20" you should always maintain even 3k RPM. Did the RPM gauge actually drop below what you had originally set?

sorry, no track, but you guys are over thinking it,, cruzing along, good weather, 80% power, nothing over rev, over power, all good, al normal.. then took stick up down, back and forth, small travel, but quick in all directions, no upside down, just left, right, up down, etc..etc. for 10 seconds,,,

lost most power, but engine stayed running... dropped altitude because no power, checked al gauges, al gauges show engine trying to die, but kept running, as I dropped the throttle, pulled in pitch, lowered pitch.... leveled out, started giving throttle, leveling out, engine back to normal after a minute or two of calmly bring it back to normal... had fuel, did not run out of gas in any tanks... weather fine, did not over speed engine, prop, not deep dive, climbs, or rolls.. just brought it back to normal and then al was good, was along flight from 1/2 down to top to Krymsk area, killed some ground targets in on killing ground targets, like trucks, no guns shooting back at my targets.. practiced with friends with flying different aircraft and helos.

no reason for the Mustang to loose al power putter and try to die.. only that it didn't take the jerking around very well. IMHO

Well, may be we are overthinking, but you're underestimating the modelling in DCS. That back and forth control movements has an effect, yes you can accumulate enough negative G's that way leading to fuel pumps and oil pumps malfunction, fuel tanks starving, and yes in DCS all of that's modelled.

Should you do that in a real aeroplane, would you complain as "bad modelled" or "something is wrong with it" after you seize the engine?

You say "all gauges showed engine dying", so what was the fuel pressure? fuel flow? oil pressure? You have the clue there on what was going on.

S!