P-40 Engine Settings as I found them (a bit weird)

August 19, 2016

A control rod movement of 2" will be still 2" whether the rod is 7" or 8" long unless something else has been changed.

Negative ghostrider.... The rod lengths reach different hook up points on the carburetor and shift the linkage calibration point.

Different combinations of the 1-3 or 1-4 linkage hook up along with specific turns of the adjustment screws create the desired manifold pressure.

For example to get to the USAAF 44.6"Hg, one would simply use Item 9, 1-4 and 1-3 linkage hook up. The adjustable stop screws would bottomed out.

Notice Item 12 brings a 56"Hg manifold pressure to 60"Hg simply by installing 1-4 rod lengths. If you only had 1-4 Rods left on the shelf in the parts supply room.....

Your boosting options are limited and only Item 10 allows you to adjust below the 56"Hg limit. Any sloppiness in the adjustment is going to produce a higher boost than the 56"Hg limit.

August 19, 2016

60"Hg was never approved by anyone for the V-1710F3R engine.

We all here know that 60"Hg was never approved by anyone for the V-1710F3R engine. Did you even read my previous post?

You have to wonder if all this 60"Hg just wasn't a maintenance error in ordering the wrong carburetor linkage rods. The rods would fit on F series engine are a preset length.

If you understand the details of adjusting the manifold pressure, it would be very easy to install the wrong preset length rods. Would not be the first time the wrong part has been installed in aviation or the wrong instructions followed.

It would be very easy to install the wrong preset length rods, right. However, this did not happen. Do you really think they approved War Emergency Rating 60"Hg because someone install the wrong preset length rod?

Critical altitude for 60 inHg/3000 rpm without ram for all V-1710s with 9-1/2 inches impeler and 8.80:1 Supercharger gear ratio is 2500 ft . So you CAN sit at sea level and get 60"Hg or more out of an Allison V-1710-F3R engine. Well, theoretically - sitting on ground will not provide sufficient cooling at this MAP. That's why i don't get your point, why would anyone want to just sit on the ground and use 60 inHg or more? It makes no sense.

You are talking about the V1710F4R which WAS approved for 60"Hg and I am talking about the V-1710F3R engine which was never approved for 60"Hg.

No, I am talking about all V-1710s with 9-1/2 inches impeler and 8.80:1 Supercharger gear ratio. I am NOT talking about limits, but power performance. I am talking about what the engine was capable of, NOT what was approved by manuals.

Unfortunately I do not have convenient power chart for V-1710-39, but it does not matter, I can show this on power charts for V-1710-35 (-E4) and V-1710-63 (-E6).

It most certainly absolutely does matter and is not applicable to a V-1710F3R installed on the P-40E.

Do your research, here is everything you need -

In a V-1710F3R engine adjusted for 56"Hg, you cannot get 60"Hg manifold pressure out of it under static conditions on a standard day. You could run it all day long and it will not get 60"Hg...end of story.

If it was adjust for the 52"Hg without a MAP, then you will only get 52"Hg static conditions on a standard day. There must be an airload on the propeller, rammed air, or al lower density altitude. Something must change the relationship in the real gas laws in order to see that manifold pressure change under static conditions.

That is the nature of a closed manifold pressure system and the point I made to you.

Manifold pressure (MAP) of V-1710 engine is regulated by a single butterfly valve (aka throttle valve). This valve is interconnected with throttle lever in cockpit. In airplane without automatic MAP regulator if this lever is in position "fully closed", throttle valve in engine is fully closed. If throttle lever in cockpit is fully forward ("fully open", "wide open"), throttle valve in engine is fully open. It looks like this -

Let's say we want fly on 42"Hg/3000 rpm. Critical altitude for this setting is 12 000 ft (all values in this post will be for 3000 rpm, without ram). How it looks without automatic MAP regulator -

Same situation with automatic MAP regulator -

What happens if pilot in cockpit set fully open throttle in 4300 ft (critical altitude for 56"Hg/3000 rpm) and at sea level? Without automatic MAP regulator, this will happen -

Same situation with automatic MAP regulator -

Now, let's say that we want restrict V-1710 without automatic MAP regulator to maximum MAP 52"Hg. Since highest manifold pressure engine produces at sea level, we have to do basically this -

What we just did? We limit maximum deflection of throttle valve in engine, which means that it can never be fully open. Normal critical altitude for 52"Hg/3000 rpm is 6100 ft, we shift this critical altitude to sea level. We significantly reduce power performance of the engine in altitude, because we shift whole altitude power curve to lower altitude. This means, that we cut 6100 ft from every critical altitude - for example, critical altitude for 42"Hg/3000 rpm will be 5900 ft instead 12 000 ft. Who would do such a stupid thing? USAAF? I don't think so.

Conclusion - there is no such thing as setting the engine without automatic MAP regulator on 52"Hg.

66"Hg is overboosting the engine because pilots were not pulling the manifold pressure back on a closed manifold system and Allison wrote the memo to tell those who did it to stop it.

That is correct, we know that here. What is your point?

It cannot be achieve under static conditions by any V-1710F3R engine.

That is not correct. I believe that this sentence is the result of your erroneous assumption that the engines without MAP regulators were somehow regulated (limited) anyway. Well, they were not, limits in manuals are just numbers written on paper and there is no way how to prevent the pilot to use the overboost. Don't get me wrong - limits are of course VERY IMPORTANT, but from practical (mechanical) point of view, there was nothing that would restrict pilot from use of overboost if he for whatever reason decided to do it.

Edit: 9-1/5 inches impeler to 9-1/2 inches impeler.

Edited August 24, 2016 by Farky

August 19, 2016

Negative ghostrider.... The rod lengths reach different hook up points on the carburetor and shift the linkage calibration point.

I see your reading comprehension has not improved.

"A control rod movement of 2" will be still 2" whether the rod is 7" or 8" long unless something else has been changed"

August 19, 2016

Manifold pressure (MAP) of V-1710 engine is regulated by a single butterfly valve (aka throttle valve). This valve is interconnected with throttle lever in cockpit. In airplane without automatic MAP regulator if this lever is in position "fully closed", throttle valve in engine is fully closed. If throttle lever in cockpit is fully forward ("fully open", "wide open"), throttle valve in engine is fully open. It looks like this -

Ok, ignore the engine manual and think about what opens the butterfly....

Linkage?

August 19, 2016

Do your research, here is everything you need -

Is exactly the same source as this:

Now, let's say that we want restrict V-1710 without automatic MAP regulator to maximum MAP 52"Hg.

Not sure what your doing here but the discussion wasn't 52"....it was achieving 60" at sea level in the P-40E V-1710F3R

It would be very easy to install the wrong preset length rods, right. However, this did not happen. Do you really think they approved War Emergency Rating 60"Hg because someone install the wrong preset length rod?

What does the P-40K have to do with the P-40E?

Different engines and airplanes....

August 19, 2016

Farky,

Limit the discussion to the V-1710F3R as installed on the P-40E, please. Different engines and airplanes are NOT relevant in any way whatsoever to the V-1710F3R installed in the P-40E. Talking about them only confuses the issue and the reader.

I am simply explaining how it was technically possible to achieve the 60"Hg in that engine. That mistake violates the operating limitations and is the reason why Allison engineers wrote the memo warning of the practice in the first place. We will call it a mistake because intentionally violating type certificate limitations on an aircraft engine would be a crime both in the civilian world and the military. The only exception is an approved circumstances by the Type Certificate holder. Obviously, the memo proves this isn't the case with the P-40E V-1710F3R engines.

That linkage adjustment also very nicely explains why the USAAF Operating Limitations do not match the 52"Hg Type Certificate Limitation from Allison.

Once more, achieving the 45.5"Hg is a very easy adjustment. You do not have to fiddle with turning a screw a set number of degrees to achieve the 52"Hg. You simply mount the 52"Hg linkage rods and bottom out the adjusting screws!! No fuss, no mess, no time spent tinkering.....no looking at charts and trying to turn a silly screw a set number of degrees buried in an engine compartment.

http://forum.il2sturmovik.com/topic/21234-p-40-engine-settings-i-found-them-bit-weird/?p=375431

August 19, 2016

Do your research, here is everything you need -

Is exactly the same source as this:

Actually those pages are from two manuals, ALD-3F2 (F series) and 3E2 (E series). You don't even bother look at them, good to know.

Now, let's say that we want restrict V-1710 without automatic MAP regulator to maximum MAP 52"Hg.

Not sure what your doing here but the discussion wasn't 52"....it was achieving 60" at sea level in the P-40E V-1710F3R

Really? Your post today 15:50 -

If it was adjust for the 52"Hg without a MAP, then you will only get 52"Hg static conditions on a standard day. There must be an airload on the propeller, rammed air, or al lower density altitude. Something must change the relationship in the real gas laws in order to see that manifold pressure change under static conditions.

I was trying explain to you on this examle, that concept of "adjust for the 52"Hg without a MAP" (you mean without automatic MAP regulator here) is wrong and cannot work. You don't get it even with pictures, which is little disappointing. The same principles apply of course to any manifold pressure, 56"Hg, 60"Hg, 45.5"Hg ...

It would be very easy to install the wrong preset length rods, right. However, this did not happen. Do you really think they approved War Emergency Rating 60"Hg because someone install the wrong preset length rod?

What does the P-40K have to do with the P-40E?

Different engines and airplanes....

So you are talking about installation of wrong rods into P-40E then, really? What this longer rod do? Opens throttle valve more than fully open?

Manifold pressure (MAP) of V-1710 engine is regulated by a single butterfly valve (aka throttle valve). This valve is interconnected with throttle lever in cockpit. In airplane without automatic MAP regulator if this lever is in position "fully closed", throttle valve in engine is fully closed. If throttle lever in cockpit is fully forward ("fully open", "wide open"), throttle valve in engine is fully open. It looks like this -

Ok, ignore the engine manual and think about what opens the butterfly....

Linkage?

Can you show some picture of this linkage and explain how it works then? Not those pictures of linkage with automatic MAP regulator you constantly use here, linkage of engine without this device.

Limit the discussion to the V-1710F3R as installed on the P-40E, please. Different engines and airplanes are NOT relevant in any way whatsoever to the V-1710F3R installed in the P-40E

Not true, you've just decided that this is so because It does not fit into your theory. Yes, in this case P-40K is not relevant to P-40E. Honestly, I assumed that you know how throttle without automatic MAP control works and therefore you know that longer rod in P-40E is nonsense. For that reason I thought you are talking about P-40K (with automatic MAP regulator). My bad.

However, V-1710-F4R (-73) is relevant, V-1710-E4 (-35) and V-1710-E6 (-63) too. I know you will not agree, but at this point I don't care.

I am simply explaining how it was technically possible to achieve the 60"Hg in that engine.

No, you don't, because you are clearly talking about throttle control with automatic MAP regulator. You are basically saying - engine without automatic regulator was somehow automatically regulated.

You are talking about this -

August 19, 2016

Farky, it is good to see some sense being promulgated in this thread. I've tried to beat some sense into Crump but I ended up wasting a lot of time and getting frustrated. Mea Culpa. Although I slightly disagree with your statement of temperature/engine failure correlation, it is fairly minor and is best reserved for a gentlemen's discussion, and not here.

August 19, 2016

Actually those pages are from two manuals, ALD-3F2 (F series) and 3E2 (E series). You don't even bother look at them, good to know.

I did look at them which is why I said the E engine does not apply. The page I posted is from the F series manual ALD-3F2.....

Really? Your post today 15:50 - If it was adjust for the 52"Hg without a MAP, then you will only get 52"Hg static conditions on a standard day. There must be an airload on the propeller, rammed air, or al lower density altitude. Something must change the relationship in the real gas laws in order to see that manifold pressure change under static conditions. I was trying explain to you on this examle, that concept of "adjust for the 52"Hg without a MAP" (you mean without automatic MAP regulator here) is wrong and cannot work. You don't get it even with pictures, which is little disappointing. The same principles apply of course to any manifold pressure, 56"Hg, 60"Hg, 45.5"Hg ...

Read the manual instructions. It is verbatim from the manual that only aircraft equipped with a MAP are adjusted to 56"Hg. Those without a MAP can only be adjusted to 52"Hg.

Right out of the manual.

August 19, 2016

Something must change the relationship in the real gas laws in order to see that manifold pressure change under static conditions.

If you look at the Allison supercharger, it vents the pressure after the impeller but before the fuel air mixture chamber. It is going to keep 52"Hg or whatever link rods and adjustment stops are set too from sea level to critical altitude regardless of whether the manifold has a map or not and any excess is going to be vented at low altitudes like almost every other supercharger design.

The 52"HG air is pushed into a fuel air mixture chamber and then into the closed induction manifold. Until a MAP is placed on that induction manifold, there is nothing past that single supercharger vent to regulate the pressure in that manifold.

Airload on the engine and propeller can then change the manifold pressure based on conditions. The MAP attaches a regulator to the induction manifold side AFTER the supercharger and fuel air mixing manifold to ensure that pressure does not change under airload.

August 19, 2016

If you look at the Allison supercharger, it vents the pressure after the impeller but before the fuel air mixture chamber.

How is it going to pressurize the intake runners, if it is venting to the outside atmosphere?

It is going to keep 52"Hg or whatever link rods and adjustment stops are set too from sea level to critical altitude regardless of whether the manifold has a map or not and any excess is going to be vented at low altitudes like almost every other supercharger design.

First, how is a throttle linkage going to somehow influence the pre-carburettor intake tract?

Second, by saying "like almost every other supercharger design" are you saying this is your wild guess or what?

The 52"HG air is pushed into a fuel air mixture chamber and then into the closed induction manifold. Until a MAP is placed on that induction manifold, there is nothing past that single supercharger vent to regulate the pressure in that manifold.

Well, GregP disagrees with you where the fuel comes in... [see attachment]

Airload on the engine and propeller can then change the manifold pressure based on conditions. The MAP attaches a regulator to the induction manifold side AFTER the supercharger and fuel air mixing manifold to ensure that pressure does not change under airload.

Partially correct, half right, but mixing wrong answers with correct ones...

August 19, 2016

Here is the supercharger:

Here is where the MAP is connected to read manifold pressure....

The supercharger already regulates the pressure going into the intake. The MAP regulates the pressure downstream of the supercharger in the manifold.

Well, GregP disagrees with you where the fuel comes in... [see attachment]

There is nothing that guys that disagrees or contradicts anything I have said.

August 19, 2016

Really? Your post today 15:50 - If it was adjust for the 52"Hg without a MAP, then you will only get 52"Hg static conditions on a standard day. There must be an airload on the propeller, rammed air, or al lower density altitude. Something must change the relationship in the real gas laws in order to see that manifold pressure change under static conditions. I was trying explain to you on this examle, that concept of "adjust for the 52"Hg without a MAP" (you mean without automatic MAP regulator here) is wrong and cannot work. You don't get it even with pictures, which is little disappointing. The same principles apply of course to any manifold pressure, 56"Hg, 60"Hg, 45.5"Hg ...

Read the manual instructions. It is verbatim from the manual that only aircraft equipped with a MAP are adjusted to 56"Hg. Those without a MAP can only be adjusted to 52"Hg.

Right out of the manual.

C'mon, these are just few random examples. I know that only engines equipped with a automatic MAP regulator are permitted to use 56"Hg. Did I ever say something else? Of course not, you can check my posts.You fight with something that does not exist, maybe you need to stop read between the lines.

Where in manual is something about adjusting engines without automatic MAP regulator to 52"Hg? Page number?

August 19, 2016

LOL, Crump.

August 19, 2016

Here is a November 1942 technical instruction on adjusting the pressure regulator to achieve higher boost ratings.

Note that Crump claims there were different "preset length rods" that could be installed

If you understand the details of adjusting the manifold pressure, it would be very easy to install the wrong preset length rods. Would not be the first time the wrong part has been installed in aviation or the wrong instructions followed.

Completely wrong: if Crump understood the details of adjusting the manifold pressure he would see that the boost adjustment is made by moving the rear end of the Cam Lever Connecting Link Part No. 1887532 from hole 3 to hole 4 on the Throttle Pivoting Crank Lever Part No. 1887489 (see page 2). Meantime, the front end of the CLCL is connected to hole 1:

Thus, 1-3 and 1-4 has nothing to do with different or "preset length rods", but the position of the Cam Lever Connecting Link on the Throttle Pivoting Crank Lever holes 3 or 4.

Allison V-1710 Adjustment of Regulator.pdf

Edited August 20, 2016 by NZTyphoon

August 19, 2016

Here is the supercharger:

Yes, there it is. However I see the fuel being sprayed before the impeller, and not in a "mixing chamber", which is what you said. I also see a one way INTAKE vent, not exhaust vent, probably to prevent suction lock on starting the engine...

Here is where the MAP is connected to read manifold pressure....

Oh? This is important and fundamentally alters the engine's function, how? I could take the pressure reading anywhere from the supercharger back to the cylinder head, would be the same.

The supercharger already regulates the pressure going into the intake. The MAP regulates the pressure downstream of the supercharger in the manifold.

This doesn't even make sense. The MAP regulates the MAP?

There is nothing that guys that disagrees or contradicts anything I have said.

Um, just have to look at GregP's quote in my post just above, and your post just above that...

You see, nothing has changed Farky.

Here is a November 1942 technical instruction on adjusting the pressure regulator to achieve higher boost ratings.

Note that there are no mythical

The adjustment is made by moving the connecting link Part No 1887532 from hole 3 to hole 4 on the throttle crank lever see page 2.

Allison V-1710 Adjustment of Regulator.pdf

Yes, the "Automatic Pressure Regulator for War Emergency Power", which the P40E never had........

TL;DR:

The P40E with V-1710-39 could produce far in excess of 60" manifold pressure as is, at sea level. And it could do it for quite some time without exploding. And with sufficient airspeed it could achieve these pressures quite a ways above sea level.

It was never "officially rated" for anything more than 56" but the pilots widely went way beyond that and multiple accounts say their engines didn't just "blow up".

Edited August 19, 2016 by Venturi

August 19, 2016

The 52"HG air is pushed into a fuel air mixture chamber and then into the closed induction manifold.

The fuel began mixing with the air before the supercharger impeller.

The text in the diagram says: fuel-air mixture to manifold. Nowhere does it say air-fuel mixture chamber.

edit: Oh, I see Venturi already commented on this.

Edited August 20, 2016 by MiloMorai

August 20, 2016

Yes, the "Automatic Pressure Regulator for War Emergency Power", which the P40E never had........

Should have read the fine print in my own document

August 20, 2016

It is like a tar baby with all the silliness and rabbit holes!

ere is a November 1942 technical instruction on adjusting the pressure regulator to achieve higher boost ratings.

Ahhh...the instructions are I posted from the April 1943 instructions and supercede the November 1942. They did not have different length rods apparently and those earlier instructions are definitely confusing as to what engines can use what. I see why Allison wrote the memo and clarified the instructions just a few months later.

Thus, 1-3 and 1-4 has nothing to do with different or "preset length rods", but the position of the Cam Lever Connecting Link on the Throttle Pivoting Crank Lever holes 3 or 4.

Which changes nothing.....

The reach of the linkage is adjusted and after reading that ball of confusion T.O. put out in November 1942, I certainly can see how some folks could have screwed up the settings.

The fuel began mixing with the air before the supercharger impeller. The text in the diagram says: fuel-air mixture to manifold. Nowhere does it say air-fuel mixture chamber.

And?

What is the hay you are trying to make? The supercharger was designed to deliver a given induction pressure into the intake and maintain it up to FTH like the majority of supercharged engines in World War II.

Allison regulated the pressure from the intake side of the impeller. Downstream of the impeller, there was nothing until the MAP was installed.

But obviously there was a program to install MAP's on every P-40E just like the overhaul manual states and we see it reinforced in the TO posted....

The P40E with V-1710-39 could produce far in excess of 60" manifold pressure as is, at sea level. And it could do it for quite some time without exploding. And with sufficient airspeed it could achieve these pressures quite a ways above sea level.

You kind of sound like you are trying to convince yourself of this Venturi.

Unfortunately it never happened....

The November of 1942 TO only shows the same exact 56"Hg as the overhaul instructions from April of 1943.

August 20, 2016

And?

What is the hay you are trying to make? The supercharger was designed to deliver a given induction pressure into the intake and maintain it up to FTH like the majority of supercharged engines in World War II.

Why am I not surprised that you do your usual dance to get out of admitting when you are wrong.

August 20, 2016

Why am I not surprised that you do your usual dance to get out of admitting when you are wrong.

Which changes nothing..... The reach of the linkage is adjusted and after reading that ball of confusion T.O. put out in November 1942, I certainly can see how some folks could have screwed up the settings.

I certainly do admit that I misread the adjustment instructions. The linkage reach is not adjusted by changing a rod but rather by moving that rod to different attachment points on the arm.

That has nothing to do with end conclusion of you cannot get 60"Hg at sea level under standard atmosphere static conditions out of a V-1710F3R. The relief valve will open on the upstream side of the impeller (intake side). There is nothing that regulates the pressure on the downstream side (intake manifold) unless a MAP is installed.

It is just that simple. Your attempt at a strawman over my mistake in how the linkage is changed does not effect the end conclusion.

August 20, 2016

Strawman Crump?

Where did I mention 60" of Hg?

A better diagram than the one Crump posted,

As can be seen fuel mixes with the incoming atmospheric pressure air before reaching the supercharger impeller.

Crump: "The 52"HG air is pushed into a fuel air mixture chamber and then into the closed induction manifold."

Your so called 'fuel-air mixture chamber' is the output end of the supercharger ducting and the fuel has already been mixed with the incoming air.

It is just that simple. Your attempt at a strawman over my mistake in how the linkage is changed does not effect the end conclusion.

Agh? Your are losing it Crump.

August 20, 2016

Where did I mention 60" of Hg?

Read the thread.

The entire argument was based on Venturi's statement that the V-1710F3R produced boost pressures of 60"Hg static power on a standard day.

Your so called 'fuel-air mixture chamber' is the output end of the supercharger ducting and the fuel has already been mixed with the incoming air.

OMG guy....You really think I did not know that?

August 20, 2016

The P40E with V-1710-39 could produce far in excess of 60" manifold pressure as is, at sea level. And it could do it for quite some time without exploding. And with sufficient airspeed it could achieve these pressures quite a ways above sea level.

If you use the given supercharger characteristics, the maximum manifold pressure achievable at sea level in standard atmosphere is about 65-66". Assuming speeds of around 540, ram air would allow you to maintain this up to 2000-3000 feet. It's interesting that the theory matches the description by Hazen, if you follow the syntax as suggested by Farky in post #610.

August 20, 2016

First of all some terms for avoiding confusion.

Automatic manifold pressure regulator (automatic MAP regulator) was also called PRESSURE CONTROL. If I mention pressure control or automatic MAP regulator, I am talking about same thing.

If I mention butterfly valve, throttle valve or carburetor throttle, I am talking about same thing.

MAP stands for Manifold Absolute Pressure (sometimes inaccurately for Manifold Air Pressure).

So do me a favor Crump and stop use term MAP for automatic manifold pressure regulator please, because this lead to confusion.

---------------------------------------------------------

Manifold pressure (MAP) of V-1710 engine is regulated by a single butterfly valve (called throttle valve or carburetor throttle). Carburetor throttle (red arrow on picture) is the ONLY thing for regulation of MAP in engine, there are NO other ways for regulation of any kind (NO devices, holes, valves or waste gates).

Since we got theory here, that at supercharger is something for regulation of MAP, let's take a look at this area -

As you can see, there is nothing for regulation at all. Supercharger seal vent works with ATMOSPHERIC PRESSURE (green on picture) not with manifold pressure, so this theory is wrong.

As you can clearly see Crump, supercharger seal vent is NOT some kind of a waste gate. Maybe i will explain to you someday what is it and what supercharger seal ventilation do.

Meet automatic MAP regulator, pressure control PC-1 -

It looks familiar Crump, right? Yes, you are talking about automatic MAP regulator all that time and you don't realized that.

How automatic MAP regulator (pressure control) works? I will not go too much into details, they are not important right now. For details see pictures.

Connection of regulator to the engine looks like this -

Note air supply lines (red), they feed regulator with MAP from engine. Also note green arrows, they show the CARBURETOR THROTTLE control lever.

What is going on inside the automatic MAP regulator? Regulator simply constantly compares momentary MAP in the engine with MAP selected by the pilot using the throttle lever in the cockpit. If regulator find out that MAP in engine is lower than MAP required by throttle lever, he opens carburetor throttle (throttle valve) in engine more. Take a look at picture details 2 and 3 for whole description.

And that's it, this is whole magic of automatic MAP regulator.

Can we now please finally stop this nonsense talking about automatic MAP regulator Crump?

------------------------------------------------------

On engine without automatic MAP regulator, carburetor throttle in engine is interconnected with throttle lever in cockpit and all "throttle work" does pilot without any help. He directly opens a closes the carburetor throttle in engine as he moves throttle lever in cockpit back and forward. Simple, just like on this awesome and highly detailed picture -

Bonus -

August 20, 2016

Read the thread.

The entire argument was based on Venturi's statement that the V-1710F3R produced boost pressures of 60"Hg static power on a standard day.

OMG guy....You really think I did not know that?

Reading comprehension problems still.

Well if you did know it then why not say its correct name.

August 20, 2016

If you use the given supercharger characteristics, the maximum manifold pressure achievable at sea level in standard atmosphere is about 65-66". Assuming speeds of around 540, ram air would allow you to maintain this up to 2000-3000 feet. It's interesting that the theory matches the description by Hazen, if you follow the syntax as suggested by Farky in post #610.

The discussion has been obtaining 60"Hg static manifold pressure at sea level on a standard day.

It looks familiar Crump, right? Yes, you are talking about automatic MAP regulator all that time and you don't realized that.

No, you did not read what I wrote. I have been talking about the false claim that the engine obtained 60"Hg static manifold pressure at sea level on a standard day.

o do me a favor Crump and stop use term MAP for automatic manifold pressure regulator please, because this lead to confusion.

Hasn't happenend...

August 20, 2016

It looks familiar Crump, right? Yes, you are talking about automatic MAP regulator all that time and you don't realized that.

Yeah...you can see attached to the 2. Carburetor Throttle Rod is the 3. Adjustable Stops....

I kind of know what I was talking about Farky. In fact, I can legally work on and return to service an Allison V-1710F3R...can you?

They are not part of the MAP regulator but the MAP regulator gets plumbed into the linkage circuit because without it....you would just have the Carburetor Throttle Rod with guess what?? Adjustable Stops!!

What do you think moves that butterfly you are fascinated with? Magic? Butterfly Fairies? How about linkage and linkage that is adjustable, has stop screws just like it shows in the nice diagram you posted?? Crazy idea I know but kind of how aircraft carburetors have worked since the dawn of powered flight. Only on these forums would that be an argument or an issue!

Why is it an argument and an issue? Because people want their airplane to do magic things it could not.

MAP stands for Manifold Absolute Pressure

.

The Automatic Pressure Regulator is a MAP regulator. Venturi and I started using just MAP for short many pages back. Sorry if that confused you.

There is three different kits that all accomplish the same thing but are mounted slightly differently depending on which kit is ordered.

Back on topic...

The V-1710F3R engine could NOT develop 60"Hg static manifold pressure at sea level. End of story.

On a second note...

The MAP regulator is what the TO discusses and just as it mentions in the Overhaul instructions.....ALL V-1710F3R engines were equipped with a MAP when they went to Service Level or Depot Level maintenance...

In other words, as soon as the aircraft came in to a shop equipped to do it....it got a MAP regulator!

Edit' to add one "Regulator" in front of a MAP so nobody gets confused....

Edited August 20, 2016 by Crump

August 20, 2016

When the manual says the engine is adjusted to achieve 52"Hg without a MAP regulator or 56"Hg with a MAP regulator....

It means that is what it will achieve static power on a standard day. That is where the stop screws on the fuel metering linkage do not allow the butterfly to open anymore....

It is complete and total fiction to say:

So you CAN sit at sea level and get 60"Hg or more out of an Allison V-1710-F3R engine.

Almost every airplane engine in existence can be overboosted under the right conditions of density altitude, rammed flight, and propeller load but to paint a picture that P-40E V-1710F3R engine developed 60"Hg static power at sea level or was ever approved to do that is not true.

August 21, 2016

Yeah...you can see attached to the 2. Carburetor Throttle Rod is the 3. Adjustable Stops....

I kind of know what I was talking about Farky.

"Kind of" being the operative words - it took other people to point out to Crump that he completely misunderstood both the Technical Orders and their diagrams, although he's now pretending that he knew what they meant all along. How typical of Crump.

In fact, I can legally work on and return to service an Allison V-1710F3R...can you?

"Legally" there are no laws preventing anyone from working on whatever engine they please - Crump can "legally" work on an Allison V-1710F3R or a Briggs and Stratton lawnmower engine - whether they would ever return to service after Crump's attention would be another matter entirely.

I have no doubt that Farky and many other forum members would be able to work on and return to service a V-1710F3R, given the service manuals that are available.

August 21, 2016

"Legally" there are no laws preventing anyone from working on whatever engine they please - Crump can "legally" work on an Allison V-1710F3R or a Briggs and Stratton lawnmower engine - whether they would ever return to service after Crump's attention would be another matter entirely.

No, I can exercise the privileges of my A&P license and with a signature, return the engine to service. You cannot.....

August 21, 2016

I have no doubt that Farky and many other forum members would be able to work on and return to service a V-1710F3R, given the service manuals that are available.

Only under the supervision of an A&P if he allows you to do the work.

The holder of a mechanic certificate or an inspection authorization may approve an aircraft, airframe, aircraft engine, propeller, appliance, or component part for return to service as provided in Part 65 of this chapter.

https://www.law.cornell.edu/cfr/text/14/43.7

A certificated mechanic may perform or supervise the maintenance, preventive maintenance or alteration of an aircraft or appliance, or a part thereof, for which he is rated (but excluding major repairs to, and major alterations of, propellers, and any repair to, or alteration of, instruments), and may perform additional duties in accordance with §§ 65.85, 65.87, and 65.95.

Almost every airplane engine in existence can be overboosted under the right conditions of density altitude, rammed flight, and propeller load but to paint a picture that P-40E V-1710F3R engine developed 60"Hg static power at sea level or was ever approved to do that is not true.

Stands as fact,

August 21, 2016

Yeah...you can see attached to the 2. Carburetor Throttle Rod is the 3. Adjustable Stops....

...

They are not part of the MAP regulator but the MAP regulator gets plumbed into the linkage circuit because without it....you would just have the Carburetor Throttle Rod with guess what?? Adjustable Stops!!

...

When the manual says the engine is adjusted to achieve 52"Hg without a MAP regulator or 56"Hg with a MAP regulator....

It means that is what it will achieve static power on a standard day. That is where the stop screws on the fuel metering linkage do not allow the butterfly to open anymore....

What are you talking about? Adjustable stops ARE part of the automatic MAP regulator (follow red arrows). Very important part, because front stop screw is crucial for setting of maximum MAP for automatic regulator. Stop talking about automatic MAP regulator please.

I kind of know what I was talking about Farky. In fact, I can legally work on and return to service an Allison V-1710F3R...can you?

No I can't, good for you. But you never work on this engine, just like me. I don't care about your experience or certificates. It doesn't matter here if you are 12 or 60, combat pilot or old lady working in a department store. Only shown knowledge counts here.

What do you think moves that butterfly you are fascinated with? Magic? Butterfly Fairies? How about linkage and linkage that is adjustable, has stop screws just like it shows in the nice diagram you posted??

I am fascinated by your idea of limitation movement of throttle so that it can NEVER be fully open. Madness.

When I wrote "carburetor throttle in engine is interconnected with throttle lever in cockpit", what do you think i mean by that? Use your imagination. Or common sense.

Linkage is adjustable, that is correct. Almost always is. But this wasn't used for limitation of maximum MAP.

On a second note...

The MAP regulator is what the TO discusses and just as it mentions in the Overhaul instructions.....ALL V-1710F3R engines were equipped with a MAP when they went to Service Level or Depot Level maintenance...

In other words, as soon as the aircraft came in to a shop equipped to do it....it got a MAP regulator!

Manuals say SOME V-1710-39 (-F3R) are equipped with automatic MAP regulator, NOT ALL. Even manual issued February 1945 say that. What if this note is about engines used in P-51? Since no V-1710-39 (-F3R) was produced with automatic MAP regulator, when they change engine in P-51, they need equip this "new" engine with regulator. Because regulator is part of the engine, not part of airplane. Just think about it.

With regard to Technical Order No. 02-5A-47 - you don't know what this Technical Order says, so how do you know it means instalation of automatic MAP regulators into P-40E? I don't know what it says neither, but I am sure that this T.O. do NOT approve or order instalation of automatic regulator into airplane. It probably approve instalation of automatic MAP regulator on engine, which is NOT the same thing. How i know that? Because Technical Orders with first number 02 are always ONLY about engine, not the airplane. If you need approve anything on airplane, you need Technical Order with first number 01. No exceptions. Instalation of engine equipped with automatic MAP regulator into P-40E was approved by T.O. No. 01-25C-112, issued autumn 1943.

Almost every airplane engine in existence can be overboosted under the right conditions of density altitude, rammed flight, and propeller load but to paint a picture that P-40E V-1710F3R engine developed 60"Hg static power at sea level or was ever approved to do that is not true.

Stands as fact,

No, it doesn't. Facts are supported by evidence, not by repeating something over and over again. You don't showed any evidence, THAT is a fact. If you now like to write "I showed them many times" - than show them again, all of them.

Last try - extrapolate this power chart for V-1710-39 (-F3R) and you will see you are wrong. Just for the record, this chart is without ram.

August 26, 2016

No I can't, good for you. But you never work on this engine, just like me. I don't care about your experience or certificates. It doesn't matter here if you are 12 or 60, combat pilot or old lady working in a department store. Only shown knowledge counts here.

Which you haven't shown much except to try and advance a gamers theory for some fantasy overboost system for your Allison engine.

My qualifications represent both education and experience. It allows me to seperate the "wheat from the Chaff" and recognize baloney when it is thrown my way. How can I tell your baloney and that of other in this thread who are trying to say the engine should develop more than the Operating Specifications allow and the Overhaul instructions show it being adjusted to produce?

1. Your theory of infinite throttle movement....

I am fascinated by your idea of limitation movement of throttle so that it can NEVER be fully open. Madness.

MMMmmm

Go check any engine....throttle movement is not infinite so why are you trying to make a case that is somehow infinite in the Allison V-1710-39 series?

It is not. The throttle linkage is fixed by the settings it is adjusted too and will only open so far. It opens to the manifold pressure the mechanic adjust's it too IAW with Type Certificate and Engine Maintenance instructions.

The math works IAW the science of engines. If our maximum power is produced at Sea Level, then it will vary IAW density altitude. That is a fixed physical relationship.

Now lets see what Allison says the Full Throttle Height of the V-1710F3R engine is at 52"Hg without a MAP regulator.....

The rated Altitude is Sea Level on a standard day. That kind of eliminates the entire thought process of it develops any more manifold pressure than the 52"Hg that is set by the linkage to produce at the throttle stops. That is a fact straight from Allison's own documentation. No conspiracy theory required, although I did enjoy your nifty hand-drawn diagrams of throttle butterflies despite the fact it had nothing to do with the conversation.

Just to cross check that fact, let's look at the normal relationship and see what manifold pressure develops at a density altitude of 3000 feet as the Allison Engineers warn us in their previous memo this overboosting will occur!

The same engine with a MAP regulator installed is allowed to produce 56"Hg manifold pressure.

52"Hg/ 56"Hg = .92857

.92857 is the density ratio difference.

Engine power varies by the reciprocal of the square root of the density ratio.

So....

1/SQRT(.92857) = 1.0377 SMOE

3000ft SMOE - 2000ft SMOE / 1000ft = 1.0454-1.0299 / 1000 = .0000155

3000 ft SMOE - 1.0377 = 1.454 - 1.0377 = .0077 / .0000155 = 496 ft density altitude increase

56"Hg represents a density altitude increase of 2504 ft over the sea level 52"Hg.

Well that keeps with what the Allison engineers say about 60"Hg representing a density altitude increase of over 3000 feet AND considerable overspeeding of the engine!

52"Hg / 60" Hg = .8666

1/SQRT (.8666) = 1.0742 SMOE

If you extrapolate, that gives you a density altitude requirement of 4980 ft density altitude increase. That is over 3000 feet density altitude increase required. So yes, Allison engineers were correct when they state to achieve such a high overboosted condition required considerable overspeeding AND an over 3000 foot density altitude increase.

In other words, the pilot has to work very hard to overboost the engine to 60"Hg. It is not going to happen sitting on the ground and not likely to happen in flight except under extreme conditions.

With regard to Technical Order No. 02-5A-47 - you don't know what this Technical Order says, so how do you know it means instalation of automatic MAP regulators into P-40E? I don't know what it says neither, but I am sure that this T.O. do NOT approve or order instalation of automatic regulator into airplane. It probably approve instalation of automatic MAP regulator on engine, which is NOT the same thing. How i know that? Because Technical Orders with first number 02 are always ONLY about engine, not the airplane. If you need approve anything on airplane, you need Technical Order with first number 01. No exceptions. Instalation of engine equipped with automatic MAP regulator into P-40E was approved by T.O. No. 01-25C-112, issued autumn 1943.

Separate discussion that has NOTHING to do with what your Allison V-1710F3R engine should produce or how it produces power nor is it applicable to your game.

I will simply point out that you are taking the instructions for the PC-1 regulator...ONE of FOUR different regulators that can be mounted and attempting to apply the fact SOME PC-1 regulators were fitted at the factory and SOME PC-1 regulators were fitted IAW the Technical Order at service or Depot Level maintenance as applying to ALL four MAP regulator designs.

Your theory that the V-1710F3R engines did not recieve a MAP regulator in USAAF service is not factual. The Technical Order is very clear, all V-1710F3R engines will receive a MAP regulator when they undergo service or depot level maintenance.

End of Story.

Edit'd - Did not upload the Standard Atmosphere Table so reader could see the SMOE values.

Edited August 26, 2016 by Crump

August 26, 2016

As for the Mystery of the RAF vs USAAF manifold pressure settings....

Density altitude effects....

52"Hg / SMOE 11000 feet = 52" /1.1822 = 43.9"Hg

End of Story.

52"Hg is what the non-MAP regulator equipped Allison V-1710F3R engines produced at sea level.

August 26, 2016

The rated Altitude is Sea Level on a standard day. That kind of eliminates the entire thought process of it develops any more manifold pressure than the 52"Hg that is set by the linkage to produce at the throttle stops.

August 26, 2016

At this point it's entertainment value from Crump, only.

How? It's Perfectly Logical. If Allison Considered 56" the absolute Operating Limit for this engine, To set it up statically at 52", so that inflight 56" would be the Maximum during Flight at normal Speeds. That is the correct way a Mechanic would set it up. What is the point in 2000ft more if Allsion can't guarantee safe operation.

Same as the Russians and the Germans Did. The VK-105s could run higher settings, but were limited to a Continuous Rated Power. Same for 109s. The DB601 and 605s were constantly in development, and the Pilots had to abide by the given limitations.

So why should we get an incorrectly Set Up Aircraft just because it was done sometimes deliberatly or as a Mistake?

The story as I see it:

52" on the Ground Static as buffer for

56" as Maximum achievable on a standard day, Absolute Never Exceed Limit.

43.9" or 42" @ 11,200 feet as Critical Altitude guaranteed Power to the the USAAF

Since this Setup seems to me to be for reasons of Safety, I guess that 52 and subsequently 56" were also still deemed safe, so that when the Pilot goes full throttle on a standard Day he wouldn't exceed the Limits deemed Safe. Since 56" would only be reached within a very narrow speed and altitude band it wouldn't really be reasonable to set it up as a setting on it's own.

This leads me to think that around some corners they approved of 52" and 56" for 5 Minutes, since they did put the throttle Stops at Safe Positions, which wouldn't allow the engine to exceed safe limits.

Edited August 26, 2016 by 6./ZG26_Klaus_Mann

August 26, 2016

Is it me or Venturi delete his post about "entertainment value only"?

August 26, 2016

I quoted him, so it's still there. But I think my Summary is quite valid.

August 26, 2016

It is valid. The math proves it....

P-40 Engine Settings as I found them (a bit weird)

Recommended Posts

Crump

Farky

MiloMorai

Crump

Crump

Crump

Farky

Venturi

Crump

Crump

Venturi

Crump

Farky

Venturi

NZTyphoon

Venturi

MiloMorai

NZTyphoon

Crump

MiloMorai

Crump

MiloMorai

Crump

JtD

Farky

MiloMorai

Crump

Crump

Crump

NZTyphoon

Crump

Crump

Farky

Crump

Crump

Crump

6./ZG26_Klaus_Mann

Crump

6./ZG26_Klaus_Mann

Crump

Browse All

Activity