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LLv34_Stafroty
06-13-2005, 12:15 PM
When got hit at engine, oil on windscreen and some grey smoke coming out, RPMs jumps at really high and engine just goes on and on without any failure, top speed is reduced some 130kmh at deck, but thats almost it. engine will not Fail after diving till RPM:s are way over 4500rpm. It doesnt lose power or anything. i got track where i fly witht it over 10 mins doing some maneuvers and put it at really high rpm:s. is this same bug with other P51 engines as well?

Sidenote. Noticed with other planes like hurricane, that when ur RPM control gets hit and rpms goes up, u can fly really long time still with over 1000rpm boost no problem. Why is 109 engine so sensitive to high RPM while other engines are not? is there any logical reason for this?

new-fherathras
06-13-2005, 12:39 PM
interesting point!

stathem
06-13-2005, 12:45 PM
http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif http://forums.ubi.com/images/smilies/51.gif

DB series engines are a far larger capacity than Merlins, and big capacity engines don't do high RPM. Don't know the stroke but I'd be guessing it's a very long one. It's also very highly stressed for it's design capablilty, especially later in life. Remember racing Merlins are still running today way over their design specs.

LLv34_Stafroty
06-13-2005, 01:00 PM
well at WW2 time 109 engines had quite long life span aye? That also tells something about it. still DB aint so much bigger capacity engine that other engines would have such an advantage over it. if Allied engines were able to withstand those RPM:s,. why didnt they then run engines at those higher rpms to get MUCH more horsepowers out from em.

stathem
06-13-2005, 01:38 PM
27/39 , virtually 50% bigger.

Stafroty, if you want to understand the answer to this you're going to have to take your Blue-tinted specs off.

I haven't got to time now to put a more complicted explantion together, I'll try to do one tomorrow, but I sure someone more knowledgeable than me will jump in with a better explanation.

stathem
06-13-2005, 02:01 PM
Sorry, 37 for the Db605 - still considerably larger, but it's the bore and stroke that's more important.

crazyivan1970
06-13-2005, 02:07 PM
If it`s a bug, add it to bug thread, provide track file. Jeez guys, for 101 time i am repeating this ... if you want something to be looked at, please keep it in one place...

p1ngu666
06-13-2005, 02:37 PM
the larger pistons and other moving parts would be heavier, so the forces on everything increase with revs, ud shake the engine too pieces from the inside.

db engines are more fragile to over rev because otherwise ppl would abuse the prop pitch system massivly.

the sabre in tiffy and typhoon could be revved to 4000rpm, due to sleave valves, fancy design, small cylinders (main thing with rev limit) and the engine block was really strong aswell.

3.0 litre V10 engines in F1 do 19,000RPM or more, produce some 900hp+ and weigh around 90kg. lots of exotic materials, and phumanic valves, rather than the classic poppet valves which cant move fast enuff http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

most powerful sabre produced 5500bhp with 4200revs and some really high boost, no special fuels tho http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

showed signs of stress at 4500rpm...
sabres about 36-7 litres btw http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

LLv34_Stafroty
06-13-2005, 02:50 PM
3.0 litre V10 engines in F1 do 19,000RPM

U got any idea how long strike those pistons make on those formulas? http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif Its "bit" different scale than we got here and "bit" different thing than AC engine.
Is here anyone who can HOST my Track??

Can anyone explain why its possible to keep RPMs ver 4000 all the time till running out of fuel without engine damage? doesnt it make much more power, moer revs more power, so its like over 30% power boost instantly, when can rev engine that high revs without fear of failure http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif sure its not bug http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

So anyone wanna host?

lbhskier37
06-13-2005, 02:56 PM
the point is you have oil all over your windscreen, so oil pressure must be gone with some seal blown, and running way over redline. I can totally understand the DB being more suseptible to high rpm (like harley big twin, those really don't like high rpm). But with the merlins in the hurricane (has been like this since FB I think) and now I see the Mustang III, these engines will run far over redline for seemingly unlimited time with only a small drop in performance. A F1 engine may able to do 19000rpm, because it was designed for that, but how is it "luftwhining" to think an engine designed to run at 3000rpm(not sure what the normal redline is, just a guess), that is damaged no less, would die reasonably fast when running at above 4500rpm? Plus, shouldnt the thrust go down by a lot when the prop governor is shot off, the prop would go to full fine pitch producing very little thrust unless you were at a really low speed.

stathem
06-13-2005, 04:32 PM
Originally posted by LLv34_Stafroty:

doesnt it make much more power, moer revs more power, so its like over 30% power boost instantly, when can rev engine that high revs without fear of failure http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif sure its not bug http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif



more revs more power?

No. Engines have a power curve. after a certain number of revs for a specific design power drops off, or at least levels.

High RPM isn't a good thing for aero engines, it requires complex reduction gearing.

Ibhskier - The Harley V-twin is a radial engine, surely you knew that? http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

LLv34_Stafroty
06-13-2005, 04:36 PM
the larger pistons and other moving parts would be heavier, so the forces on everything increase with revs, ud shake the engine too pieces from the inside.

Pingu, so in other words, you are sayin that DB should be more durable under gunfire cos of heavier parts/design? ?

Anyway, the track i got, anyone intrested? pager me and ill send it via Email if its SO hard to understand.

Willey
06-13-2005, 04:40 PM
old one. Any Allison or Merlin engined planes have this... RPM governor destroyed, rpm go up, but no engine damage results...

stathem
06-13-2005, 04:43 PM
Stafroty, pop to the Tempest thread and look at some of the info Pingu posted in there,, notably the bottom of the first photo of text on pg20 about lighty built DB engines and heavily engineered British ones.

LLv34_Stafroty
06-13-2005, 04:52 PM
Stathem, U say thsoe engines should run forever with high rpm??? O_o oh C‚¬īmoon, dont be such a...
U say its realistic?

stathem
06-13-2005, 05:09 PM
I was replying to the line "Why is 109 engine so sensitive to high RPM while other engines are not? is there any logical reason for this?" in your first post - I thought you had a sensible question, not simply a moan about the other guys DM

Do you want the Merlin to go bang or the DB to run at 4000rpm? Make your mind up.

p1ngu666
06-13-2005, 06:13 PM
Originally posted by LLv34_Stafroty:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">the larger pistons and other moving parts would be heavier, so the forces on everything increase with revs, ud shake the engine too pieces from the inside.

Pingu, so in other words, you are sayin that DB should be more durable under gunfire cos of heavier parts/design? ?

Anyway, the track i got, anyone intrested? pager me and ill send it via Email if its SO hard to understand. </div></BLOCKQUOTE>

depends which way u look at it http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif
depends most on the outer casing or parts u could knock off easily. if u get a bullet or whatever in the workings of a engine u will most likely screw it up.
from overrev theres the acceloration, decceloration and rotational forces, they will go up like G forces, u could also get valve float, on the linked system of the db the manifold pressure could also increase leading to detonation which can spot heat parts massivly.

ingame, the performance drop from cps failure was pretty big (my pc is broke so i cant play 4.0 or 3.0)

also i dont think u can get a similer failure on the DB engine or 190

LLv34_Stafroty
06-13-2005, 06:22 PM
stathen, im not asking that we would get that prop pitch cheat back in use, im asking that merlin as well would seize form that damage, and im askin that some other engies would not able to withstand such high RPMs cos those other engines werent made used on such hi rpm.

performance failure werent BIG imo, if i still can go some 440kmhias at deck. and u can run like that with no fear or overheating what soeverm with no oil.. . Get realistic, aint it bit Wrong?

VW-IceFire
06-13-2005, 09:39 PM
Originally posted by LLv34_Stafroty:
When got hit at engine, oil on windscreen and some grey smoke coming out, RPMs jumps at really high and engine just goes on and on without any failure, top speed is reduced some 130kmh at deck, but thats almost it. engine will not Fail after diving till RPM:s are way over 4500rpm. It doesnt lose power or anything. i got track where i fly witht it over 10 mins doing some maneuvers and put it at really high rpm:s. is this same bug with other P51 engines as well?

Sidenote. Noticed with other planes like hurricane, that when ur RPM control gets hit and rpms goes up, u can fly really long time still with over 1000rpm boost no problem. Why is 109 engine so sensitive to high RPM while other engines are not? is there any logical reason for this?
It sounds like the overreving you get with a Spitfire or any of the other Mustangs except that the engine blows up when they are finished. And this one does not...interesting.

I can tell you that the Spitfire Merlin does definately overrev and blow up. I did test that to confirm...so it seems to be only the Mustang Mark III (and not all Merlins anyways).

lbhskier37
06-13-2005, 09:51 PM
Try it in a hurricane icefire, the last time I checked they will run forever without a prop governor.

Stafroty It's not really that the DBs are built heavily so much that it has a very long stroke. Engines with long strokes don't like high rpm because the pistons have to move a long way. The merlin has a shorter stoke, so it can run higher rpms. Its kinda like how you can run really high rpm in a Yamaha R1 because it has large diameter short cylinders, while in a harley big twin you have small diameter long cylinders.

Stathem Yup, the two cylinder radial is a thing of beauty. I know quite a bit working for them. There actually is a kit out there to use a harley big twin for a small aircraft engine. Not something I would try with a shovelhead, but the twincams are pretty reliable.

Tvrdi
06-14-2005, 01:39 AM
why wer talking about DB engine...initial post was about merlins and their bug..indeed you can drive with merlin for a long time after taking damage in the machine area...its an old bug and its really strange that they didnt fixed that in the long fixing period...

JG53Harti
06-14-2005, 02:00 AM
@LLv34_Stafroty

you found a host for your track ? If not let me know.

LLv34_Stafroty
06-14-2005, 06:57 AM
NO, ive have not find a host. If u can host it, i sure will send it to u for chekin.

Vipez-
06-15-2005, 03:33 AM
pist√¬§ mulle lobbyss√¬§ joskus ni voin pist√¬§√¬§ ne sivuilleni..

JG53Harti
06-15-2005, 07:11 AM
LLv34_Stafroty you has PM http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

JG53Harti
06-15-2005, 07:48 AM
Here you can download the .ntrk for this Bug (http://frank.equitatura.de/engine.ntrk)

LLv34_Stafroty
06-15-2005, 07:54 AM
Thx Harti!!