Power

who like those power ratings for mustang ??

Not sure if I understand your question?

Not sure if I understand your question?

90in/3000rpm with water injection 2160hp at 10kft

Do we have tha P-51H or any plan for it in DCS World?

Ohh, no, nothing.

So, about what is that question?

Do we have tha P-51H or any plan for it in DCS World?

Ohh, no, nothing.

 

So, about what is that question?

question is simple do you like it or not.

did you notice how ram air is cripling power output below critical alt for supercherger

question is simple do you like it or not.

did you notice how ram air is cripling power output below critical alt for supercherger

Oh yeah. I noticed it. Probably because the airflow at that particular speed isn't compatible with the RPM setting of the supercharger at low altitudes? There may be an interaction with the water as well, I'd say?

In a gas turbine, there are some similar behaviors, but I believe the airflow is too great for that particular supercharger setting. When you increase the mass flow, the turbine requires more horsepower to drive the compressor, the extra mass flow comes from the high speed and water injection (water injection works like an injected mass flow system), so perhaps that's why we see a loss of horsepower in those graphs.

Oh yeah. I noticed it. Probably because the airflow at that particular speed isn't compatible with the RPM setting of the supercharger at low altitudes? There may be an interaction with the water as well, I'd say?

 

In a gas turbine, there are some similar behaviors, but I believe the airflow is too great for that particular supercharger setting. When you increase the mass flow, the turbine requires more horsepower to drive the compressor, the extra mass flow comes from the high speed and water injection (water injection works like an injected mass flow system), so perhaps that's why we see a loss of horsepower in those graphs.

In case turbine engine that would be partialy true becouse you can compensate this by increaseing fuel distribution to engien creating more power at higher air speeds like in planes for example

but in piston engine its difrent story air flow thorugh out piston engine is determined by engine rpm and manifold pressure and you are limited for example to 61in/3000rpm so whne engine supercharger face rammed air you cant let that air go in to supercharger becouse it would increase manifold pressure, so at the supercharger intake there is a throttle connected to boost pressure regulator. in case ram air this throttle would be closed even more to throttle down supercharger and throttled supercharger will take more power to boost up to 61"(significant icing may occure behind throttle becouse rapid pressure drop) this effect passing away when supercharger hitting it's critical alt in that case ram air helps boost up to 61" lifting max throttle alt by a lot at high air speeds

another way to control boost would be air bleed valve at the supercharger outlet in that case things would be just like you said more air mass flow more power required to boost up, but this solution is no go becouse carb is mounted at spuercharger intake so plane would bleed out air fuel mixture

and the third way to control boost is to set supercharger speed idepedently of the engien crank shaft like germans did in bf109

ok i got it ram air increasing energy and throttle dont change much in that case. so this slight increase in power while climbing is becouse throttle efficiensy rising up while beeing open more and more while climbing do i get this right ??

In case turbine engine that would be partialy true becouse you can compensate this by increaseing fuel distribution to engien creating more power at higher air speeds like in planes for example

but in piston engine its difrent story air flow thorugh out piston engine is determined by engine rpm and manifold pressure and you are limited for example to 61in/3000rpm so whne engine supercharger face rammed air you cant let that air go in to supercharger becouse it would increase manifold pressure, so at the supercharger intake there is a throttle connected to boost pressure regulator. in case ram air this throttle would be closed even more to throttle down supercharger and throttled supercharger will take more power to boost up to 61"(significant icing may occure behind throttle becouse rapid pressure drop) this effect passing away when supercharger hitting it's critical alt in that case ram air helps boost up to 61" lifting max throttle alt by a lot at high air speeds

another way to control boost would be air bleed valve at the supercharger outlet in that case things would be just like you said more air mass flow more power required to boost up, but this solution is no go becouse carb is mounted at spuercharger intake so plane would bleed out air fuel mixture

and the third way to control boost is to set supercharger speed idepedently of the engien crank shaft like germans did in bf109

Yes. Fuel flow increases with speed, as well as to maintain AFR near the stoichiometric region.

Either way, nice comment Yo-Yo. Thanks!

Yo-Yo pls tell me in merlin 66 there are 2 steps in cooling air first is interstage cooling between 1/2 stage of supercharger and second is aftercooler(using coolant for heat exchange. question is this coolant circuit is it connected to engine coolant or is it seperate system??at first look looks like seperate system) another question in v-1650-7 in p-51 is this setup is similar or quite difrent ??

You mean 46/2700 in Mustang?

i can see the slight power increase at every each power setting is it pumping loose due to throttling ?? or something else??

at 46/2700 looks like good 50hp difrence maby little more

from 0 to crit alt ft very similar from high blower switch point to it's crit alt

i understand that those graphs corespond to net power.

the same thing - if you keep MP constant, charge temperature decreases with altitude. So, charge density increases.

i alwayes think that during climb air at spuercharger inlet change but it cant realy :P same flow speed same pressure only temp is changing. so supercharger alwayes works with full power in p-51 when engine is at 3000rpm:doh:

natural aspirated engines(SI) while running below max power encounter pumping losses(throttle partialy closed) but in supercharged ones it must be mitigated then.

what about DB605 and its supercharger ?? So if i uderstand this in case of bf109 faster you flying more power you get becouse bf109 has ability to lower superchargher speed.

so for example at constant ata 1.2 supercharger will gradualy slow down while accelerating. So bf109 is able to avoid this overboost power drop. i assume thast bf109 has somekind ram intake ??

It uses STATIC pressure.

no ram air and it can maintain full boost up to 24k ft that is crazy

It used ram but the hydro-coupling used static pressure to control.

so ECU had static pressure sensor for reference but ECU had to have pressure sensor in manifold to control MP so if ramm air was a thing in bf then while accelerating it should somehow unload supercharger or in some case supercharger wasnt even needed when ram air was enought to provide little boost like in shalow dive at very low ATA bearly exeeding outside pressure for example.

If you take a look at the DB flow chart you can see which device is in charge of supercharger speed and of MP limiting.

Ok i have general idea looks like this was responsible for MP