P-47 interconnecting engine controls

[Reaperr]

Ii wanna ask what is purpose and advantage and disadvantage  of interconnecting throttle and prop pitch,  with interconnecting turbocharger controls. And for better performance it should be mapped RPM/prop pitch control with and turbocharger to different buttons or interconnecting turbocharger and prop pitch controls should be mapped on the same button?

[Praetor]

Isnt prop pitch automatic?

[YankeeDoodle]

Generally speaking you are going to leave the controls disconnected for taxiing, takeoff, and landing. Rule of thump is to have full rpm during taxiing, takeoff, and landing so the prop blade angle stays lower and improves throttle response. In combat it's just a matter of preference. With the controls disconnected you'll be able to fine tune  you're engine for max performance, but your workload will be higher. With the controls disconnected you're workload is reduced but you will loose some performance, mostly in acceleration.

 

Preator, the propeller RPM effects the propeller blade angle or pitch of the propeller blades. High RPM will put the propeller blades into a lower angle, while lower RPM will put the blades into a higher angle. high blade angles are used for high altitude cruising, and low blade angles are used for things like landing and takeoff. This is a short and simple answer to a very complicated topic.  

[Rattlesnake]

Basically the faster a prop is moving through the airstream the easier it is to turn. So it needs to change angle to take a bigger bite as the plane gets faster, ideally.

Because of this all fixed pitch props are a compromise. If a fixed prop were pitched to let you use maximum engine power at climb speeds you would have to throttle back to avoid over-speeding the engine at level speed built up. And if a prop were pitched for high speed your climb would be reduced, since your engine would never get up to its maximum acceptable RPM. Of interest is that aviators were aware of this problem at least as far back as the Wrights. But it took awhile for technology to catch up to a solution.

The solution is a variable pitch prop. Now a prop can be made manually adjustable, wherein the pilot continually changes the angle as speeds change to keep his desired RPM, but by far the best system and the one almost universally used is a constant rpm prop, in which the pilot sets a desired RPM and the blade angle varies automatically to hold that speed.

 

[montag]

Just to clarify the prop control in the 47 sets the desired RPMs. There is a mechanism which then varies the prop pitch automatically to achieve that desired RPM. I don't ever connect the RPM control to my throttle in the 47 since it is something I already have bound for almost all of the russian planes anyways.

 

Also in the 47 you can turn off automatic prop control and change the pitch on your own if you feel like playing around with it. You can also do this in the 109s and I'm sure some other planes but I am not sure which ones.

[Bremspropeller]

9 hours ago, Praetor said:

Isnt prop pitch automatic?

 

Depends on what you mean by that.

 

The prop-governor tries to hold a certain RPM. In oder to do that, it automatically adjusts the pitch/ blade angle of the props.

Thatere's no *direct* control over the blade angle (like there is in e.g. german airplanes, where the prop governor job is done by the pilot).

 

The setting of the desired RPM is done by the pilot, though. If you link the RPM-liver to the throttle, you'll have low rpm at low throttle and hi rpm at high throttle.

That is sort of what you want on most occasions. If you want to max-perform the engine (no matter where: range, power-output, etc.) you'll have to take manual control of all levers and set them to each of their respective optimum positions.

 

[Siegfried]

I was trying interconnect the controls but I can't do it. There's a key for that? I try CTRL+S without result, maybe I am doing something wrong. I have all real in realism options.

[PainGod85]

You need to enable the interconnecting action with a keypress, and then you must manually move the levers until they're next to each other so they can be connected.

[Haza]

Just now, Siegfried said:

I was trying interconnect the controls but I can't do it. There's a key for that? I try CTRL+S without result, maybe I am doing something wrong. I have all real in realism options.

 

Go to engine control set-ups in the  key mapping area via settings.  Under the engine controls,  at the bottom of that page, the last 2 items relate to both interconnect controls.  You can select what you want or just use the default keys identified.

 

Hope this helps!?

 

Regards 

[Siegfried]

18 minutes ago, Haza said:

 

Go to engine control set-ups in the  key mapping area via settings.  Under the engine controls,  at the bottom of that page, the last 2 items relate to both interconnect controls.  You can select what you want or just use the default keys identified.

 

Hope this helps!?

 

Regards 

 

YES!!! Thanks for the help. I didn't find that new keys in the bottom.

 

Thanks to both.

Edited November 24, 2018 by Siegfried

[Praetor]

I would think you always want highest safe RPM possible, even with low throttle so you have the power when you need it. 

[Warpig]

 

[Guest deleted@83466]

 

9 hours ago, Bremspropeller said:

 

Depends on what you mean by that.

 

The prop-governor tries to hold a certain RPM. In oder to do that, it automatically adjusts the pitch/ blade angle of the props.

Thatere's no *direct* control over the blade angle (like there is in e.g. german airplanes, where the prop governor job is done by the pilot).

 

The setting of the desired RPM is done by the pilot, though. If you link the RPM-liver to the throttle, you'll have low rpm at low throttle and hi rpm at high throttle.

That is sort of what you want on most occasions. If you want to max-perform the engine (no matter where: range, power-output, etc.) you'll have to take manual control of all levers and set them to each of their respective optimum positions.

 

 

27 minutes ago, Praetor said:

I would think you always want highest safe RPM possible, even with low throttle so you have the power when you need it. 

 

So the way I look at it is this:  for convenience, link the throttle and RPM if it suits you.  In combat, if you want 2700 RPM to be maintained, and don't want it to come back with the throttle, than just de-link it.  I ---think--- that by allowing the RPMs to retard along with the throttle, you are allowing the plane to be more aerodynamically efficient than having those big paddles out there windmilling, so if you want to "coast", it might be a good idea to keep them linked.  I think the advantage of having them de-linked, and behaving like most other planes, is that when you pull back your throttle, you'll have more of a braking effect from that big prop...this is correct, right, aerodynamicists?  That might be exactly what you want in combat, like for example, in a flat scissors fight. where you are trying to have as little displacement forward as possible relative to your enemy, and being able to decelerate slightly quicker is important. 

Edited November 24, 2018 by SeaSerpent

[danielprates]

I think @Praetor got this right from the start. In one sentence he nailed it on why binding the RPM lever is a weird thing. 

 

As far as linking the throttle with the supercharger, I think it makes sense to treat both levers as one single 'thing' since it all comes down to your desired manifold pressure. It makes no difference if your throttle is lower and boost is higher, or the other way around, if the MP needle is marking the same thing in the gauge. Save for specific situations (landing, high altitude etc), you just check your MP gauge and that's it, so moving them together is indeed a workload decrease - two levers at once and one instrument to check. The way I have been doing it, is to always have it interlocked as a rule, and only unbind them in some situations where I feel I must - rare, though! I imagine its more like a standard manufacturer procedure in specific situations, like, "in situation 'x', favor the use of throttle in place of the supercharger to avoid engine damage". 

 

However ...  binding also  the RPM setting? When you set it to an specific RMP it will remain there no matter what, save from overspeeding or low throttle, so what would be the point in any situation to keep increasing or decreasing RPM all the time along with your throttle? The way I see it:

 

1 - During landing you need low throttle and high RMP, so no interlocking is even possible here;

2 - In combat you set an ideal RPM and leave it there. I admit there are situations where you need to change your RPM to an specific intention, many stated above, but those situations won't necessarily coincide to where your throttle lever is at the moment. Besides, in combat you are constantly moving the throttle - imagine constantly changing the RPM to high-low-high-low-high all the time!

3 - In cruise, climb, or for that matter almost any situation, the manual indicates a correct RPM regime, which will not be in pair with the throttle lever setting most of the time. 

 

I am still to understand the 'why' on the RPM binding! I am sure there must be a reason, but so far it escapes me. 

 

 

[LukeFF]

19 minutes ago, danielprates said:

I am still to understand the 'why' on the RPM binding! I am sure there must be a reason, but so far it escapes me. 

 

Workload reduction. Simple.

[danielprates]

1 hour ago, LukeFF said:

 

Workload reduction. Simple.

 

That figures, but in what situations? 

[=362nd_FS=RoflSeal]

I don't know why the RPM control links with the throttle. In the manuals, it mentions that the turbo and rpm control can be pushed up with the throttle alone, but if the throttle is reduced, the RPM lever will stay where it is and has to be manually retracted. This is added to the aircraft can increase power to combat without detonation.

Edited November 24, 2018 by RoflSeal

[Guest deleted@83466]

2 hours ago, RoflSeal said:

I don't know why the RPM control links with the throttle. In the manuals, it mentions that the turbo and rpm control can be pushed up with the throttle alone, but if the throttle is reduced, the RPM lever will stay where it is and has to be manually retracted. This is added to the aircraft can increase power to combat without detonation.

 

Yes, one of the manuals does say that it only goes forward and has to be pulled back manually. However, LukeFF has a picture of a P-47D throttle quadrant where it has a claw on the back of the RPM lever, in addition to the one on the front.  That means that on some planes,  it wasn't exactly as the generic manual stated it was, and it could obviously be fitted so that it went back with the throttle, as well as forward, if the pilot desired.

Edited November 24, 2018 by SeaSerpent

[Nocke]

I can only recommend to watch the video linked by Warpig. You are discussing stuff wrongly here which is being explained nicely there. Especially it makes clear that it is NOT ideal for power to link throttle and turbo. In reality, that is. Don't know about how it is simulated.

[Guest deleted@83466]

2 minutes ago, 216th_Nocke said:

I can only recommend to watch the video linked by Warpig. You are discussing stuff wrongly here which is being explained nicely there. Especially it makes clear that it is NOT ideal for power to link throttle and turbo. In reality, that is. Don't know about how it is simulated.

 

Who is "You"?  Me? 

[Nocke]

10 minutes ago, SeaSerpent said:

 

Who is "You"?  Me? 

No Someone saying its just about the manifold pressure and that it would not matter if you achieved it one way or the other.

[Guest deleted@83466]

Sorry, had a little Robert De Niro moment there.

[montag]

You never want the turbo ahead of the throttle. Also at high altitudes you will need to have it behind otherwise you will over-speed the turbo. Keep the light blinking.

[Willy__]

8 minutes ago, TheKillerSloth said:

You never want the turbo ahead of the throttle. Also at high altitudes you will need to have it behind otherwise you will over-speed the turbo. Keep the light blinking.

 

Im not used to the 47; if the light is blinking that means that the turbo is over-speeding ?

[YankeeDoodle]

The light will be solid if the turbo is idle or over-speeding. If it is blinking you are good.

[montag]

Blinking means it is good. Check video 3 I posted earlier in the tips section of the forum. The light is to reduce pilot work so you don't have to watch its exact speed at all times. The limit is 18250 , but there is a line for you to look at so you don't need to know this limit even if there was no light. The light will become solid once you are overspeeding. So reduce turbo or throttle and turbo to get it to stop blinking. This will only really happen at high altitudes. There's a lot of redundancy because that turbo is what really gave the 47 the edge and allowed its engine to operate at high power even up with the bombers. They didn't want pilots breaking the thing as it was a pretty advanced piece of equipment.

 

In the video the narrator states to just keep that light blinking and you are all good.

Edited November 25, 2018 by TheKillerSloth

[LukeFF]

4 hours ago, SeaSerpent said:

However, LukeFF has a picture of a P-47D throttle quadrant where it has a claw on the back of the RPM lever, in addition to the one on the front.  That means that on some planes,  it wasn't exactly as the generic manual stated it was, and it could obviously be fitted so that it went back with the throttle, as well as forward, if the pilot desired.

 

 

 

Edited November 25, 2018 by LukeFF

[Haza]

Just now, LukeFF said:

 

 

 

 

I notice that my in game water switch looks different, is that a different model throttle?

[Legioneod]

51 minutes ago, Haza said:

 

I notice that my in game water switch looks different, is that a different model throttle?

I believe that throttle is from the earlier blocks.

[[DBS]TH0R]

For max performance you don't want to link them together. Here is a post from a discussion about the problem earlier this year:

 

On 5/30/2018 at 10:33 PM, ZachariasX said:

 

You indeed do need two levers, one for throttle, and one for turbo.

 

If you have only one lever on your HOTAS, there are ways to deal with this.

 

Either you place turbo on any axis you have (this is ok since you will have to be operating the turbo lever as careful as with the Me-262's throttle) OR you can make a button that basically toggles your throttle lever as turbo lever, while leaving the other lever in place. This way, you can set throttle, then toggle the button to make your throttle lever to be the turbo lever and set that one accordingly. For common flight regimes, this will be okay.

 

In combat, there is a problem causing that neither this solution, nor direct linkeage of the throttle will be really useful. Here's why:

 

Know that you have to keep the turbo at least at a minimum speed for it to operate normally and to be able to spin up if you forward the turbo lever. Not doing so will give you the best of all "turbo holes", meaning it will take some time to come up to speed and it will sobstancially lag your input, especially if you forward it from a very low setting. You cannot make coarse movements with the turbo. You can with the throttle. but if you reduce throttle less than your turbo, you will cause excessive strain on your turbo. This will make youl go home at lower altitude.

 

If you have throttle and turbo linked, this might help you to not do something stupid when fighting for your life BUT you are at risk of overspeeding your turbo. Past 12'000 ft, the power from your engine is progressively generated by the turbocharger, at 28k ft, most of the power is actually made by the turbocharger. Up there, it is the speed of the turbo (and the bearing temperature) that sets the limit of your power setting. Above that altitude, your supercharger will not be able to produce full permissible MAP anymore. But you might be still in a position to make the turbo spin faster and you consequently will blow your turbo, not your engine.

 

You will see that when you climb, you rapidly approach an altitude where you have full throttle, and from then on, you can move the turbo lever forward until you reach an altitude where the turbo starts to overspeed. Having throttle hard linked to turbo, you will close the carb at an intermediate setting and the turbo will have a harder time providing full MAP. You are hurting yourself if you always keep this link.

 

Another problem is carb tempereature. If you advance turbo down low and MAP rises, so will carb temperature. The first stage supercharger gives you all the MAP you can have down low. Now if you have the turbo operating along with that, you will heat the air flowing into your engine even more and with rising carb temperature, there goes the efficiency of your engine. This means you have to balance turbocharging and supercharging such that you have an ideal carb temperature and then you are getting more out of your engine compared to the poor schmocks who can't fine tune their engine like that.

 

It's really cool.

 

 

In short, linking them together will give you famous turbo lag and less engine efficiency when you need the power the most.

 

I've yet to test the plane and how it handles in the sim.

Edited November 25, 2018 by [DBS]TH0R

[Legioneod]

19 minutes ago, [DBS]TH0R said:

For max performance you don't want to link them together. Here is a post from a discussion about the problem earlier this year:

 

 

 

In short, linking them together will give you famous turbo lag and less engine efficiency when you need the power the most.

 

I've yet to test the plane and how it handles in the sim.

 

You're going to have turbo lag regardless of whether you link them or not, it's just less noticeable when the turbo is spooled up.

 

It's less efficient when the turbo and throttle are linked the higher you get, It's best to leave them unlinked or unlink them when getting to higher altitudes.

Personally I do a bit of both, it just depends on if I feel like messing with the turbo or not.

 

The turbo modeling is rather "simple" (still the best I've seen) at this stage, so you don't have to worry about any ill effects of keeping the turbo full forwards all the time.

[Ehret]

The linked controls works well enough considering no turbo failures are modeled as now. To get maximum performance from your Jug you have un-link them; that's especially true when facing the UFO. When you get 40% fuel, carry 4 guns, keep throttle fully open, your rpm at 2500-2550rpm and fly at 7000m it's possible to keep up in level flight. Controlling the MP by the turbo lever is possible if one is delicate enough; you can use the RPM control for faster changes but keep the throttle open to nullify throttling loses as much as possible.

 

On autumn Kuban the Thunderbolt can run 587km/h at the deck in such manner. The pesky timer will kill the engine two minutes sooner (MP is going to be 67") but there is the possibility.

[PainGod85]

4 hours ago, Haza said:

 

I notice that my in game water switch looks different, is that a different model throttle?

 

It's from a plane without the K-14 gyroscopic sight.

[Rattlesnake]

6 hours ago, Ehret said:

The linked controls works well enough considering no turbo failures are modeled as now. To get maximum performance from your Jug you have un-link them; that's especially true when facing the UFO. When you get 40% fuel, carry 4 guns, keep throttle fully open, your rpm at 2500-2550rpm and fly at 7000m it's possible to keep up in level flight. Controlling the MP by the turbo lever is possible if one is delicate enough; you can use the RPM control for faster changes but keep the throttle open to nullify throttling loses as much as possible.

 

On autumn Kuban the Thunderbolt can run 587km/h at the deck in such manner. The pesky timer will kill the engine two minutes sooner (MP is going to be 67") but there is the possibility.

Am I the only one now officially confused AF about how to manage the engine in the Jug?

[ZachariasX]

2 minutes ago, CMBailey said:

Am I the only one now officially confused AF about how to manage the engine in the Jug?

On Berloga, just move both all the way to the front and use the boost switch as blip switch.

 

[Rattlesnake]

5 minutes ago, ZachariasX said:

On Berloga, just move both all the way to the front and use the boost switch as blip switch.

 

I’ve been turning my turbo all the way up, linking throttle and prop and running at about 87% on both for high cruise, turning on the boost for “Combat” (it lasts awhile that way) and then just firewalling the throt+prop for WEP. But if I understand this issue correctly, I am potentially losing horsepower by using turbo to gain MP that engine supercharger could give me by moving the throttle farther forward??? I dunno.

Edited November 25, 2018 by CMBailey

[Ehret]

Just now, CMBailey said:

Am I the only one now officially confused AF about how to manage the engine in the Jug?

 

In short... (at least worked for me including successful escapes from UFOs)

 

There 3 ways; each next increase performance but adds to workload:

- link everything

- link the throttle and boost only; set rpm to 2500-2550 for best level speed up to 7-8Km; set rpm to 2700rpm for best acceleration at any alt

- when chased by the Haunebu set rpm as above; the throttle full open and manage MP by the boost lever only

 

For oil radiator: 100% for climbing; 50% for level flying.

Inter-cooler: 50% for the whole sortie.

Front cowls: 0% when running/diving; 0% when climbing on water injection; increase as needed when climbing without water. (the latter especially important when higher - a sudden overheat can seize engine if you don't react quickly)

 

When on the water injection set mix to 100% - will increase power even more and there is no point saving fuel as boosted time is so much more precious. Remember to set mix back to 85% when done with the water injection.

 

Just now, CMBailey said:

I’ve been turning my turbo all the way up, linking throttle and prop and running at about 87% on both for high cruise, turning on the boost for “Combat” (it lasts awhile that way) and then just firewalling the throt+prop for WEP. But if I understand this issue correctly, I am potentially losing horsepower by using turbo to gain MP that engine supercharger could give me by moving the throttle farther forward??? I dunno.

 

Superchargers always incur losses when throttled. It can be as much as 10% of total power and throttling a turbo is even worse - throttling the latter can damage it. That's why the boost lever shouldn't be moved past the throttle; in the sim it's not so important because we don't have turbo failures modeled, yet. Linking is safe and convenient but will cost some performance. If it's worth to un-link will depend on circumstances.

Edited November 25, 2018 by Ehret

[Rattlesnake]

I thought the rich setting was only for when the autorich is malfunctioning...another deviation?

[=gRiJ=Roman-]

I hope Requiem makes one of his stunning videos soon. 

[ZachariasX]

1 hour ago, CMBailey said:

I’ve been turning my turbo all the way up, linking throttle and prop and running at about 87% on both for high cruise, turning on the boost for “Combat” (it lasts awhile that way) and then just firewalling the throt+prop for WEP. But if I understand this issue correctly, I am potentially losing horsepower by using turbo to gain MP that engine supercharger could give me by moving the throttle farther forward??? I dunno.

No, the point is that the supercharger requires a lot of force to spin it. The force required to spin that impeller is rpm dependent. This means, it will always eat 300 hp off your shaft hp at 2700 rpm regardless of your throttle setting. Propeller rpm settings matter here. Conversely, at 2200 rpm it will eat less hp.

 

Now, you going at 2700 rpm, throttle lever to 30 inches or so, the engine then will produce 1200 hp (just guessing) minus 300 hp eaten by the impeller giving you a net power of only 900 hp. This means the efficiency of your engine is only 75%. If you shove the throttle forward it will produce 1800 hp (as example) minus 300 hp, lifting efficiency to 84% or so. It comes now as logical when the supercharger has an easier job giving more power to the more efficient engine to obtain a certain power output. The 9% difference you will gain on the prop shaft. See, that’s a lot. Does that make sense?