Help with JBK. DC 6 please. What does MAP mean and how to use it

Gentlemen,

 

I have started flying the DC6. Reading the polit notes it talks of selecting, e.g. 33 inches of MAP......etc.

This is what I am having difficulty doing, as I don't fully understand.

Am I right in thinking MAP means mixture and pitch?

In the cockpit I see the green pitch levers, and I see ( lower down) some red mixture levers?

I can move each of these, of course, but how that gives me 33 inches of MAP or 36 inches of MAP etc, I do not know.

I see the rpm decreases etc on the engine dials, but don't fully understand the other dials.

 

What should I look for as I change these pitch and mixture settings as the flight progresses.

 

. Sorry if it's basic, but I feel so near to being able to fly this plane, but am stuck. Acronyms aren't my strong point😀

 

Thank you

MAP= MAnifold Pressure. It will take some practice adjusting Prop Levers (RPM for non-fixed props), red Mixture Levers ( for fuel mixture as you climb in altitude) and Throttle levers (Engine speed and MAP).

 

Plenty of info on all of this by using Google Search.

Edited June 7, 2020 by mrzippy
Corrected my mistaken identity of MAP!

MAP is short for MAnifold Pressure. It's a reading of the "vacuum" in the engine manifold.

 

On the panel there will be two instruments for each engine that are used to set the power: one is the MAP, or MP, gauge and the other is the tachometer. So with four engines there will be four MP gauges and four tachometers. The throttle is used to set MP and the prop control sets the RPM (Revolutions Per Minute) on the constant speed propeller. There is some interaction between them, so after adjusting one, sometimes you have to make a minor change in the other.

 

If you've flown the Mooney or the Baron, you've needed to use these gauges, too, to set the power.

 

In a normally aspirated engine (that is, not turbocharged or supercharged) you'll be able to set the MP up to around 29" to 30", or so, at sea level (lower at higher altitudes), and you might note that this is the same range as the altimeter setting/barometric pressure reading, which is because the current barometric pressure (actual, not adjusted like for an altimeter setting) is the maximum MP available to you. Thus at 5,000 feet you'll get a max MP around 23" to 24", due to the lower actual air pressure at that altitude.

 

But the DC-6 is supercharged, so you'll have more power (higher MP) available to you, even up to the much higher altitudes. With supercharging and turbocharging (two different ways of letting the engine get more power up high), many aircraft can maintain 30" MP up to some "critical altitude" which is often somewhere between 12,000 feet and somewhere in the 20s, depending on the specific design. Some can even "boost" up to 50" or a bit more (P-51, etc.), though many have a 30"-35" limit. Look it up on Wikipedia for more information on that.

 

As for how to use them, the prop(s) should be set for max RPM before takeoff (lever(s) pushed full forward), and the throttle(s) should be used to set power. Once airborne, the throttle(s) should be brought back to a more modest setting (in a Mooney or Baron perhaps 25"), THEN the prop(s) should be brought back to a climb setting -- perhaps 2500 RPM in a Mooney or Baron -- as recommended in the manual. There will be further changes when you level off for cruise and, depending on the aircraft and altitude, perhaps additional adjustment during the climb.

 

Mixture is a totally different thing, and is another subject.

 

Hope this helps.

Sorry, you're right, Larry! MAnifold Pressure. For some reason I always stick in Air?? I'll turn in my mechanic's license! :(

But the DC-6 is supercharged, so you'll have more power (higher MP) available to you, even up to the much higher altitudes. With supercharging and turbocharging (two different ways of letting the engine get more power up high), many aircraft can maintain 30" MP up to some "critical altitude" which is often somewhere between 12,000 feet and somewhere in the 20s, depending on the specific design. Some can even "boost" up to 50" or a bit more (P-51, etc.), though many have a 30"-35" limit. Look it up on Wikipedia for more information on that.

You will need more power than that to persuade a lumbering DC-6 to climb.

 

Typically, you need to climb at 41" MAP, 2400 RPM at between 700 and 1000 fpm initially (depends on take-off weight of course) and you can keep adjusting power to maintain that until above 11000 when the blowers can be switched in to give a little more. Even so, getting to a high altitude in a heavy propeller airliner is hard work and it is sometimes necessary to level off for spells to get some speed up to avoid stalling.

 

When you get there, you cruise at between 30 and 36" of manifold according to needs.

 

The settings for a full flight are too complex to detail here, I recommend to the OP to take a look at the California Classics web site for more flying information and loads more lovely aircraft like this too.

 

Best regards,

 

John

I agree about the CalClassics site! I highly recommend getting the "Super Conny" to practice your engine/prop/mixture settings. If the prop RPM isn't brought down shortly after takeoff, you literally fall out of the sky!:eek:

 

I also highly recommend Manfred Jahn's C-47 to practice engine/MAP/prop control.

You will need more power than that to persuade a lumbering DC-6 to climb.

 

More power than what? If you'll re-read my post, you'll see that I very carefully did NOT specify any settings for the DC-6, since I know little about the airplane. Rather I offered information about what some/many aircraft will use. The only specifics I included were for the aircraft I know, such as Mooney and Baron. I DO know, though, that the big iron like that have totally different parameters than typical light aircraft, such as lower RPM and higher MP, but my specs were intentionally very generalized for the principle involved.

 

But thanks for adding settings for the DC-6 -- that should help the OP, too.

Sorry, you're right, Larry! MAnifold Pressure. For some reason I always stick in Air?? I'll turn in my mechanic's license!

 

Technically, MAP means Manifold Absolute Pressure, but the more generalized acronym I've always used, and what I learned about flying decades ago, is MP, or Manifold Pressure. The MAP term could easily be confused for Missed Approach Point, or even chart (map). I don't know why the MAP term is so common in simming, though.

 

If the prop RPM isn't brought down shortly after takeoff, you literally fall out of the sky!

Huh? That's not real world in any aircraft I've flown. Granted that reducing RPM after takeoff avoids excessive stress on the engine, and it reduces noise, but "fall out of the sky"?

 

I also highly recommend Manfred Jahn's C-47 to practice engine/MAP/prop control.

 

Could be good, but the Baron or Mooney would work as well, since they both have constant speed props and an MP gauge.

Well, when flying both the C-47 and the Super Conny, if the prop RPMs are not reduced down within about 6-8 minutes after takeoff, the engines quit producing power even though the props are still turning.

In the C-47 the engines catch fire and quit producing thrust for the props.

 

Had to dig way back in my photo archives for this shot! My point was that even though you can set MAP, prop RPMs, etc on the default Mooney and Baron, there are no consequences if you don't.

 

Edited June 7, 2020 by mrzippy

Thank you very much gents, This has helped a lot. After posting I did some (more) digging and found enough to make things reasonably clear.

I have since flown a couple of times using the DC6 pilot notes where there are recommended settings for climb and cruise.

However, what isn't mentioned is the zmixture settings. There are mixture levers , one for each engine, which at default I presume are "rich".

Am I right in thinking that as I climb then I move the levers in increments to "lean" the mixture, or are they left alone, or how are they used exactly. I have leaned them but not by a terrific amount and I haven't seen much difference in engine performance, i.e. It doesn't climb easier with mixture leaning.

I'll visit the recommended sites for more reading.

Thanks again

Well, when flying both the C-47 and the Super Conny, if the prop RPMs are not reduced down within about 6-8 minutes after takeoff, the engines quit producing power even though the props are still turning.

In the C-47 the engines catch fire and quit producing thrust for the props.

 

Had to dig way back in my photo archives for this shot! My point was that even though you can set MAP, prop RPMs, etc on the default Mooney and Baron, there are no consequences if you don't.

 

[ATTACH=CONFIG]219412[/ATTACH]

 

Ouch, that would ruin your whole day! Thanks for sharing that pic Charlie!

 

Rick :cool:

if the prop RPMs are not reduced down within about 6-8 minutes after takeoff, the engines quit producing power even though the props are still turning.

OK, they must be trying to simulate overstressing the engine (neat pic, BTW). And most engines DO have a maximum time for running at full power (often 5 minutes). And, of course, those big radials are much more sensitive to running them properly (or not) than the smaller ones in light aircraft. Have you tried reducing MP first, perhaps down to 25" or less to see if that will adequately reduce the stress and let them run longer before pulling back the props?

 

Since I don't have the aircraft you specify I was never aware how they behave.

Flight sim computer finally melted down. CPU cooling fan quit. No sim until I get a new Win 10 computer. Just using a Chromebook for now.

Flight sim computer finally melted down. CPU cooling fan quit. No sim until I get a new Win 10 computer. Just using a Chromebook for now.

 

Try replacing the cooling fan?

Sorry to hear that, Charlie. Guess you'll have to change your signature line... :pilot:

Poetic, happens just when posting about fan rpm.:D

Try replacing the cooling fan?

 

Old computer and RGB monitor discarded at the local electronics recycle center.

Thank you very much gents, This has helped a lot. After posting I did some (more) digging and found enough to make things reasonably clear.

I have since flown a couple of times using the DC6 pilot notes where there are recommended settings for climb and cruise.

However, what isn't mentioned is the zmixture settings. There are mixture levers , one for each engine, which at default I presume are "rich".

Am I right in thinking that as I climb then I move the levers in increments to "lean" the mixture, or are they left alone, or how are they used exactly. I have leaned them but not by a terrific amount and I haven't seen much difference in engine performance, i.e. It doesn't climb easier with mixture leaning.

I'll visit the recommended sites for more reading.

Thanks again

Glad you are getting on OK.

 

In the real world you have three or four position mixture levers which are not reproduced on the models, although they can be represented by add-on panel gauges. These would be used at Auto-Rich and Auto-Lean positions in flight, you use Auto Rich on climb and also on finals (in case of going-around) but otherwise you have the choice of doing as you are, or using Microsoft's automatic mixture option which can be set tow ways. Change for all aircraft in Settings or by inidvidual aircraft with a simple setting change in the aircraft's aircraft.cfg file. Under [piston_engine] look for fuel_air_auto_mixture=0 and change it to fuel_air_auto_mixture=1. Running fully auto is the method recommended at California Classic.

 

If you fancy a 15 hour flight (OK, I'm joking) you could do worse than watch this video on YouTube, search for "Why is this vintage airplane full of Dogs and going to Norway?" And yes, that DC-6 really did fly non-stop for 15 hours just a few days ago! Wow . . .

Best regards,

 

John

 

PS:

Inuss - I meant more power than you were referring to. I could say read my post properly too but . . .

:)

Glad you are getting on OK.

 

In the real world you have three or four position mixture levers which are not reproduced on the models, although they can be represented by add-on panel gauges. These would be used at Auto-Rich and Auto-Lean positions in flight, you use Auto Rich on climb and also on finals (in case of going-around) but otherwise you have the choice of doing as you are, or using Microsoft's automatic mixture option which can be set tow ways. Change for all aircraft in Settings or by inidvidual aircraft with a simple setting change in the aircraft's aircraft.cfg file. Under [piston_engine] look for fuel_air_auto_mixture=0 and change it to fuel_air_auto_mixture=1. Running fully auto is the method recommended at California Classic.

 

If you fancy a 15 hour flight (OK, I'm joking) you could do worse than watch this video on YouTube, search for "Why is this vintage airplane full of Dogs and going to Norway?" And yes, that DC-6 really did fly non-stop for 15 hours just a few days ago! Wow . . .

Best regards,

 

John

 

PS:

Inuss - I meant more power than you were referring to. I could say read my post properly too but . . .

:)

 

Thank you John. I had a go with non auto mixture and it was ok. However, I "lost" an engine (4) doing that because it seems I lean d it too much on the levers and it shut down!

However, I did land Ok😀

Btw two things, does the DC6 have airbrakes( you can see I've com from jet airliners😀)

And where can I get some good sounds for the engines for the db6 for FSX running on XP

 

Thanks again

The DC-6 has the same type of air brakes as most any piston aircraft with a constant speed prop, that is reduce power -- an engine with a constant speed prop at an idle power setting adds a LOT of drag (jets aren't that way), so you can get a steeper descent than you might want just by bringing the power back. However, you also have to remember to do things gradually or else the engine could cool too quickly resulting in potential engine damage. Of course that big iron is worse about that than the lighter aircraft, but most any piston engine aircraft with cowl flaps (and some without) has that problem to some degree, depending on the specific aircraft/engine design (yes, even the Mooney or C-182).

A few propeller airlines use their main undercarriage (but not the nose wheel) for braking (the DC-7 is one) but you can't do that on any old aircraft because most are not strong enough to cope with the airflow against them. Cowl flaps cause air resistance too, on some aircraft you are directed to use the cowl flaps as additional braking.

 

Best regards,

 

John