Throttle and RPM

[Vortex01]

OK I know you use the throttle to go fast and control speed. But I am not clear on when and how to use the RPM settings. Any help would be nice thanks.

[Krusty]

RPM, basically, is related to power and to prop pitch. By reducing RPM you're lowering the revolutions per second (duh) which uses less fuel.

When you decrease RPMs past a certain point, your MAP (that your throttle controls) drops with it, further conserving fuel.

Also, as you reduce RPM, the prop pitch changes, reducing the amount of work the engine has to do.

You can watch this as you come in for a landing. Set auto angle (ctrl X) and pull up E6B. Turn engine off, and note speed. Now reduce RPM and watch your speed jump! Now increase RPMs to max again and watch your speed slow down (while in a descent)!

I think less RPMs = greater prop pitch, making the prop closer to being feathered than at full RPMs, which = narrower bite into the air for the prop, but creates an airbrake for the plane.

[Murdr]

RPM sets your prop speed, and indirectly your prop pitch.  You set the RPM (+&- on the numberpad) and the prop governor will adjust the pitch of the props so they will maintain that RPM.

What can you do with that?  Mainly, you can adjust RPM along with the manifold pressure settings to cruise at a better fuel efficiency than you would at full throttle and RPM.  

Also, you can use it to reduce drag when gliding.  At low RPM setting the blades have the slimmest profile with your direction of travel.  That means you'll have less drag with the power off and be able to glide further.  One note on that is if you're expecting to lose power from damge, you'll need to set your RPM before engine failure.  Otherwise you are stuck with the prop pitch that was set when the engine failed.




Sorry, same info in previous post.  My typing speed is ok but damn my spelling.

[SlapShot]

"By reducing RPM you're lowering the revolutions per second (duh) which uses less fuel."

[Krusty]

Yeah, that was just a brain fart. I meant "minute", of course.

[Vortex01]

you are still correct since a decrease in RPMinute is going to be directly preportional to the decrease in RPSecond. :-)

[Traveler]

So in Multi engine aircraft  in aces high if you are going to lose an engine, you should select the engine (Shift 1 or 2) reduce Manifold pressure and reduce RPM to the lowest setting , press the E key to shut the engine down in a feathered condition?

[4deck]

Yes, If you can, if you can shut the engine down because of damage abslutley. Theres a nother thread that was very good about that.

One of the biggest things I use it for is bombing.

Its the only time I really use every sortie. For instance. I have tables that i built at what alt, what RPM, and Manifold my true air speed will be for a B24/B17.

It helps your approach alot to slow down, if you have to make *suttle* changes going slower and still fairly accurate. ( J and L ) keys.

But if you can at 14-15k ( my prefered alt ) you should have a true airspeed indication of 246, but 244 is not uncommon. With RPM of 24 and 40 on the Manifold and doors open. That right there with a full load of ords is a very deadly speed for a Base hit. Anyway.

The bombing side of house should really get very familiar with these settings. Ina  fighter, the only benifit I see is exactly that. Shutting a damaged engine down, or trying to get home with 3-4 mins fo fuel.

I

[Krusty]

You usually don't have to do that for multi-engine planes. Most multi-engine planes allow for one engine to be feathered, in case it needs to be shut down.

[DweebFire]

now i've only flown fixed-pitch aircraft in real life so far so my understanding is limited.

Now does't reducing the prop pitch (which lowers RPM) also allow you to dive more quickly in some aircraft?

Also, do the aircraft in this game without Hamilton Standard props or any aircraft without a propellor that can maintain a set RPM have that disadvantage of actually having RPM fly all over the place?

[Benny Moore]

No, unfortunately all aircraft in Aces High use the same system (the American one).

[HomeBoy]

The RPM setting in Aces High is pretty well "gamed."  About all it does for you is save you fuel but pulling it back a little.   It doesn't work like a real aircraft.

The RPM setting in a real aircraft controls the variable pitch prop (if so equipped:  example Cessna 182) which works sort of like a gear shifter in a car.  Full RPM means the blades are at the flattest angle which produces the least resistance for the prop thus the most RPM.  This is like the low gear in a car.  It provides the most power but the least speed.  As you pull back on the RPM, you're increasing the pitch on the prop blades which causes more "bite" into the air which in turn causes the RPMs to drop but gives you  more cruising speed (to a point).  It's sort of like shifting into a higher gear.  If you increase the pitch too much, your speed will begin to drop back off because the engine is not strong enough to handle that much pitch.  That's like having to down shift as you go up a hill.  Finding the best RPM for a given altitude and barometric pressure is somewhat trial and error although the pilot's operating manual shows published RPMs and manifold pressures (throttle) for various conditions.

Personally, I'm glad HT has chosen to "game" a lot of this stuff as most of us enjoy fighting rather than fooling around with engine management too much.

[Benny Moore]

It actually works pretty much how it should, for American aircraft, except that it's "idiot proof."  In reality, the tricky bit was not having the MAP and RPM settings conflicting.  If they did, you could lose your engine.  The other problem is that we gamers fly around at full throttle all day, and thus ordinarily do not need to worry about lowering RPM settings.  In reality, you'd need to be changing them as you climb and dive, because you wouldn't be charging around with maximum power (unless you were in a fight).

The problem with the simplified version is that, although it obviously appeals more to the masses than would a realistic version, it makes the game/simulator less like flying and definitely less like flying a real warbird.  Since I want little more than to fly a real warbird, that saddens me.  I shall have to keep my fingers crossed for Knights of the Sky.

[HomeBoy]

Originally posted by Benny Moore
It actually works pretty much how it should, for American aircraft,  ....

Uh, no.  In AH, max RPM always produces maximum performance.  American or otherwise.  I don't call that "pretty much how it should work."

I'm not going to argue with you further about it though because it's not a big deal.  It's a game.