Electro Power for small aircraft and drones

Hello Ivan,
Thanks for your reply.
It is all quite contradictory and criptic from what you say, and that´s why it doesn´t work.

You say: "Now that you have changed your target HP at Sea Level, what the manifold pressure really should be is YOUR guess. "
I´m not guessing - it´s what the simulator came up with.

You say: "The problem is that you seem to be changing so many different things all at the same time that it isn't clear what a good baseline version of this engine really is."
You suggested lowering Critical Altitude, so that at 100% throttle one would only get what would normally be got with 90% throttle, in order to avoid having to tap the "9" Key. This obviously entailed Hp adjustments, which in turn required Drag adjustments, and because Cd0 is 0.013 and can´t be changed, the other two Drag entries serve for that. Skin Friction DOES work very well, contrary to what you say. The frontal area is not implied by skin friction, just the polished (or not so polished) surface.

You had suggested that it was impossible for a 350 Hp Standard TIO-540 to attain N777XT´s performance, and the reference was the 90% throttle power needed for 90% throttle performance at 17500 ft: i.e. 402 or 403 Hp and 440 mph.
Power at S.L. came out to be around 400 Hp.
These two things then, were what I used as a basis.

Why else did you suggest I write down the Hp needed for 440 mph at 17500 ft?

You say: "If you were still trying for 350 HP at SL, I believe it is a pretty good guess. Now that you have changed your target HP at Sea Level, what the manifold pressure really should be is YOUR guess."
I was no longer trying for 350 Hp at S,L. but more, and that came out by itself as I have just said.

You say: "I am really not sure what you are doing at this point. You are doing something which changes Sea Level and low altitude (5,000 Feet) Horsepower and that is definitely out of scope for this exercise."
It is the result of having Full throttle giving only 90% throttle power at 17500 ft, which I thought that was the point.

You say: "The reason I do not believe you understand what I was trying to tell you is that if what I was suggesting was properly done, the Sea Level manifold pressure, Horsepower and speed DO NOT CHANGE.
I understood just the opposite.

You say: "Why would you equip the aeroplane with Water Injection? Why does it need water injection?··
I already explained that. It is a measure to separate 5-minute max. power (take off and extra climbing power) from max. continuous power, to prevent prolonged abuse of 100% throttle giving maximum power. I chose Option 2 of F10 Extra Power, which happens to be Methanol-Water, because if abused, it only destroys the supercharger, not the whole engine.
However, this Extra F10 power is easily deleted.

You say: "It is quite difficult without working on this flight model myself to see all the different things that may arise and tell you exactly what to do in each case, but it seems like that is what you are expecting from me. On top of that, you are also messing with induced drag and skin friction which may have some consequences you do not expect."
Well, I´m very sorry about that, but your explanations are difficult to understand.

So, if I understand correctly now, for this exercise, max. manifold pressure DOES have to be reduced (or not, depending on speed after the critical altitude is lowered), and most importantly, the exercise is done after all, with S.L. Hp ONLY at 350 Hp, the objective being to get 440 mph with 402 Hp at 90% throttle at 17500 ft.

Cheers,
Aleatorylamp.
 
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Hi Ivan,
Right then. This has gone around full circle again, because when you suggested this exercise, we were already at 402 Hp for S.L. You will see why:
I set S.L. power under full throttle back to 350 Hp again, with 39.5 Hg. At 17500 ft, 100% throttle achieves 403 Hp and 440 mph.
There is no way that reducing Boost Gain and/or Manifold pressure can get 90% throttle to achieve 403 Hp and 440 mph.
To obtain this kind of performance with 90% throttle, necessarily the Torque Curve must be increased, and the Friction Curve decreased.
This way 90% throttle at 17500 ft can give 403 Hp and 440 mph, with 35.4 Hg., (and full throttle delivers 251 Hp and 252.2 mph with 38.7 Hg).
However, Sea level power is obviously no longer 350 Hp as it was initially.
This time it is 394 Hp with 39.5 Hg, giving 379.5 mph. (With a small adjustment 381 mph can be got).
Now, rising to 5500 ft, full throttle will give 413 Hp, 399 mph and 39.5 Hg. (With a small adjustment, 402 mph can be got).
Quite honestly, I haven´t the faintest clue about how to achieve what you are suggesting. I just don´t see it. I´m sorry, I just don´t understand what you are trying to explain.
Cheers,
Aleatorylamp
 
Hello Aleatorylamp,
I don't know why you still don't understand. I am also running out of ways to explain without actually doing it myself.

I had started typing a long explanation of the points I had explained before and that you seem to be not understanding.
I got interrupted and when I got back to this message, I ended up deleting most of it because I realized that I would not be writing anything different from what I had written in prior posts.

Again we are at an impasse as they say. I am pretty sure I know how to handle these issues but don't want to do the necessary research and iterative testing on a project that is not my own. I can't seem to find a way to explain how to do things in a way that you can follow along.

I do not believe I can post anything useful to you at this point because it would just be a repeat of what I have posted earlier.

- Ivan.
 
aleatorylamp said:
Right then. This has gone around full circle again, because when you suggested this exercise, we were already at 402 Hp for S.L. You will see why:
I set S.L. power under full throttle back to 350 Hp again, with 39.5 Hg. At 17500 ft, 100% throttle achieves 403 Hp and 440 mph.
There is no way that reducing Boost Gain and/or Manifold pressure can get 90% throttle to achieve 403 Hp and 440 mph.
To obtain this kind of performance with 90% throttle, necessarily the Torque Curve must be increased, and the Friction Curve decreased.
This way 90% throttle at 17500 ft can give 403 Hp and 440 mph, with 35.4 Hg., (and full throttle delivers 251 Hp and 252.2 mph with 38.7 Hg).
Click to expand...

Let's just address ONE issue, the one you list above.
I believe you are incorrect.
If you reduce supercharger boost, you reduce critical altitude. Below critical altitude, nothing really changes.
Now if I set critical altitude to 12,000 Feet, the power at 17,500 Feet will be different from if I set critical altitude to 15,000 Feet.
There will be a combination at which a critical altitude below 17,500 Feet gives 403 HP at 17,500 Feet at FULL THROTTLE.
You need to find that combination without messing with Sea Level power or Manifold Pressure limits.

- Ivan.
 
Hi Ivan,
I´m so sorry to disappoint you, and I know that it is costing you a lot of effort to try and explain. I constantly go back in the thread to try and make "head and tail" of what you mean, and just can´t see the light. I have no reference point to rely on, or what really to look for or to have as an objective.
Your last message just came in - thanks very much indeed for the effort.
I realize that if I reduce supercharger boost, I reduce critical altitude. Below critical altitude, nothing really changes.
But of course, lowering Critical Altitude we will no longer have the mentioned performance at the mentioned altitude at 90% throttle but at 100% throttle, i.e. we get Top Speed-Cruise at that altitude with full throttle instead of 90% throttle because we have lowered Critical altitude and that means that beyond Critical Altitude, Supercharger Boost has waned, and power will go down despite throttle being at 100%.
So, starting from the 350 Hp at S.L. basis again, with the 39.5Hg max. manifold pressure, the objective being 403 HP at 17500 ft at full throttle, the way to do it is to go lowering Critical altitude until this happens.
Let´s see what happens...
Anyway, your patience is commendable indeed!
Cheers,
Aleatorylamp.
 
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Hello Aleatorylamp,
I was just getting a snack after posting my message and checking my phone which was last on this this site.....

I believe that although you may understand what I was recommending now, you are starting with the wrong baseline.
The problem is that while 403 HP represented a 90% power against an earlier engine with over 400 HP at Sea Level and about 450 HP at 17,500 Feet, it does not represent the same thing with a 350 HP at SL engine.... Or does it?
I believe when you complete the exercise with the 350 HP engine, you will find yourself just about exactly where you were about two weeks ago.

- Ivan.
 
Hi Ivan,
So... What´s the right baseline?
The second line of my post #162 reads:
"I set S.L. power under full throttle back to 350 Hp again, with 39.5 Hg.
At 17500 ft, 100% throttle achieves 403 Hp and 440 mph."

So, here we already had the exercise objective accomplished without further doing anything at all !!

Notwithstanding, I did it again, and this time it was:
With Boost Gain at 2.6, Torque and Friction Graphs set for 350 Hp at 500 ft.
Remember that Cd0=0.013 (AirEd=26)
All with 100% Throttle:
__500 ft: 350 Hp, 357 mph (a bit slow), 39.5 Hg, 36.8 prop.
_5500 ft: 368 Hp, 388.4 mph (very slow), 39.5 Hg, 40.6 prop.
17500 ft: 404 Hp, 440.7 mph (acceptable), 38.7 Hg, 45.0 prop.
Any reduction in Boost Gain just brought reductions in power and speed. I tried 1.8, 2, 2.2, and 2.4...

With Boost Gain 2.57 and minor power adjustments, it was very slightly different, but not worth setting up a list for.

So I repeat: What is the right baseline?

You say: "I believe when you complete the exercise with the 350 HP engine, you will find yourself just about exactly where you were about two weeks ago."
So... What IS the point? I ask again, because I must confess I can´t help getting feeling I´m being led up the garden path here... no offense meant. This is just tortuously going round in circles.

Could it be possible that what you are trying to achieve (by making me do all the reiterative tests) won´t work?

Incidentally, I eliminated the trailing-edge wingroot-fairing bleeding through the fuselage seen from above.🛩️

Cheers,
Aleatorylamp.
 
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Hello Aleatorylamp,
The BIGGEST problem here is that you seem to have great difficulty actually following directions.
When I suggest something to do, it is in a certain context. The problem is that you generally do something else first because it is "logical" or "necessary" at which point the original context for the instructions is invalidated. Ir MIGHT still work, but usually it doesn't.

This latest deal with playing with reducing critical altitude is a perfect example. When I gave you that advice, you had a aircraft that was doing slightly over 400 MPH at 5,000 Feet with about 470 HP and with about 450 HP at Sea Level. It was overly fast at 17,500 Feet but was pretty much matching the spec at 90% Throttle.
So, I suggested observing the power level that was being achieved at 17,500 Feet at 90% Throttle (403 HP) and reducing the Critical Altitude until that was the new limit. Note that with just the Critical Altitude changing, the difference in power between the maximum at the new Critical Altitude and 17,500 Feet would have been pretty close to 90% Throttle.
Instead, you spend a couple days changing all kinds of other stuff and messing with the Sea Level power and changing drag numbers with skin friction and induced drag before you finally understood what my original advice was.
By the time you tried to take my advice about critical altitude, it probably wasn't applicable any more because so much else had changed. THEN is when I tell you that we already were here a couple weeks ago and this was a waste of time.
The problem is that the engine parameters and power curve were not at the same starting point as when the advice to adjust critical altitude was given to you. I believe it was good advice at the time but not after everything else changed.

- Ivan.
 
Hello Ivan,
No. The BIGGEST problem here are the ambiguous and cryptic comments surrounding the directions you give. I KNOW that eleven days ago we were no longer talking about 350 Hp at S.L., but just over 400 Hp, so WHY now mention the 350 Hp again and again recently, if that has already been surpassed?
So now it´s back to the 402 Hp at S.L. OK.
Going in circles made me quite dizzy.

Update: OK, it worked.
I lowered Boost Gain from 2.56 to 2.34 and adjusted Torque and Friction curves again for 401 Hp at 500 Ft, leaving Max MP at 39.5 Hg, Cd0 at 0.013, and putting Induced Drag at 5785, Skin Friction at 200, with the hope of some extra speed.

I suppose the 444 mph speed peak at 15000 ft and a 455 Hp power peak at 14000 ft means it´s Maximum Power and Top Speed at around the new Critical Altitude. Above and below these altitudes, performances are lower. Then, going up to 17500 ft, speeds gradually become Top Speed-Cruise. Below the new Critical Altitude, they would also be Top Speeds, of course.

At 17500 ft, 401 Hp and 440.3 mph are happening with 34.8 Hg at full throttle.
Previously, full throttle here was giving 452 Hp and 452.2 mph with 38.3 Hg, which now is history.
At 5500 ft, 420 Hp and 401.7 mph with 39.5 Hg
At 500 ft, 401 Hp and 382.2 mph with 39.5 Hg

So what does all this mean?
Technically, the simmer can go 100% throttle continuously at Top Speed-Cruise above Critical altitude, but only for 5 Minutes at Maximum Top Speed below Critical Altitude.

At last....😰
Thank you very much again, indeed.
The long, torturous track through the fog led to a refreshing, sunny lake.
Cheers,
Aleatorylamp
 
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aleatorylamp said:
Hi Ivan,
I,,,,,
So, starting from the 350 Hp at S.L. basis again, with the 39.5Hg max. manifold pressure, the objective being 403 HP at 17500 ft at full throttle, the way to do it is to go lowering Critical altitude until this happens.
Let´s see what happens...
Anyway, your patience is commendable indeed!
Cheers,
Aleatorylamp.
Click to expand...

Hello Aleatorylamp,
This is from the tail end of post number 165.
I don't know WHO is typing this stuff if it isn't you. This is a message from YESTERDAY.
How would YOU interpret this message?
This is why I wonder WHY THE HECK you are going back to the old 350 HP engine.
This was ONE DAY AGO, not two weeks. Care to explain????

- Ivan.
 
Hi Ivan,
Sure. There were several comments referring to the 350 Hp at S.L. that I misunderstood and which totally threw me off - and I thought the thing to do was to get the 350 Hp at S.L. back in again, which I found very strange, as we had already passed that point 11 days ago with my Post #150.

From your Post #160:
>>> If you were still trying for 350 HP at SL, I believe it is a pretty good guess. Now that you have changed your target HP at Sea Level, what the manifold pressure really should be is YOUR guess.
... Here I thought the implication was that it was a mistake to change it.
and:
>>> Why would you use a more expensive custom Thunderbolt version?
... So I thought a cheaper standard 350 Hp Thunderbolt version was more logical.

From your Post #166:
>> The problem is that while 403 HP represented a 90% power against an earlier engine with over 400 HP at Sea Level and about 450 HP at 17,500 Feet, it does not represent the same thing with a 350 HP at SL engine.... Or does it?
... This comment I thought implied that I should be using 350 Hp for SL again - or not.
and:
>>> I believe when you complete the exercise with the 350 HP engine, you will find yourself just about exactly where you were about two weeks ago.
... Here I didn´t understand anything anymore, because it seemed to infer doing the exercise in order to get to the point we were 2 weeks ago, which was bizarre... Whatever for?

It just seems that I don´t understand some things you say, and understand just the opposite. Sorry about that.
Maybe I can´t see the forest because there are too many trees, or perhaps the neurons work differently, or maybe they are starting not to work at all. I´ve always had problems with abstract things, but it seems to be getting worse. I must be getting old.

Anyway, at the end, it is interesting.
Flying the plane this way, one must only be careful to use 100% throttle for 5 minutes up to 14000 ft. Beyond that, the 39.5 Hg manifold pressure starts waning, and one can fly full blast flat out all the time, all the way up to the ceiling (which appears to be 25000 ft).

I made a new speed/power vs altitude chart, but I don´t know if it is really of interest. I could put it into the next message if you want.

Cheers,
Aleatorylamp
 
Hello Aleatorylamp,
There is this concept of cause and effect.
You specifically asked about whether 39.5 inches Hg was a good Manifold Pressure to use.
Post 160 that you are quoting here was a response to that:
"If you are still trying for a 350 HP engine, then it makes sense. Now that you are trying for a different power engine, what the Manifold Pressure should be is your guess."

I had already hinted to you about 10 different ways as to what the manifold pressure was more likely to be. That is what looking through the Type Certification Data Sheets is about. You need to use what data is available to you, not just tweak Air file parameters.

The rest of my comments came AFTER you were stating you were restarting with a 350 HP engine which of course made no sense.

- Ivan.
 
Hi Ivan,
Like I´ve already said, I misinterpreted all those comments on the 350 Hp at SL engine and thought that for the exercise that´s what it had to be, which obviously was nonsense, because we were long since already upto a 400 Hp at SL engine.

Update:
Regarding Maximum Manifold Pressure, if 39.5 Hg was your good guess for the 350 Hp engine, although this also seems to work for the 400 Hp engine, possibly 40.7 or 42 Hg could be better for that one, as the extra 50 Hp have to come out of somewhere, I suppose.
There wasn´t a TCDS for a 400 Hp TIO-540 Lycoming, although as I said some time ago, I found manifold pressures quoted for different lower powered engine types, ranging from 36 up to 44 Hg, but none for a combination of Hp and RPM as the souped up TIO-540-NXT.

So, I´ll try out 40.7 and 42 Hg, which are the next two MP values in the engine types list, and see what happens. Perhaps 42 is already too high.
You already mentioned many times I should look up max. MP in the TCDS, but what good would that do? There is no TCDS for the engine needed, thanks to the secretive TIO-540-NXT modders. Who says they didn´t use max. MP at 41.0 Hg, or 41.5 Hg for a 400 Hp version?

At least your 39.5 Hg guess for a 350 Hp engine was mentioned for one of the engines on the list, which made it quite plausible, and in effect, proved to be a very good guess.

My guess would be that 40.7 Hg would be OK, and 42 Hg would be too high, so at most it might be 41.5, which is on none of the published TCDS for these engines. Speculation and guesses again...
Another Update:
Well, I just tried out 40.7 Hg max. manifold pressure, and had to keep the same Boost Gain of 2.34 as before. Performance at 17500 ft didn´t change, but I got a few more Hp and mph at S.L. and at 5500 ft altitude. So this could be a plausible possibility too, perhaps more appetizing for the simmer, who would probably value some more power at low altitude.

Cheers,
Aleatorylamp
 
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Hello Aleatorylamp,
Part of the ability to make a good guess is to know a little about OTHER engines that exist and their characteristics.
You actually have an awful lot of information available to you with the TCDS on other TIO-540 engines.
Think about what you know or can guess: None of them probably run any kind of ADI. That means that even the highest manifold pressure listed in those TCDS (44 inches Hg) is not sufficient to require ADI. Is that consistent with other air cooled single stage supercharged engines?

If you think 39.5 inches Hg is reasonable MP for a 350 HP engine do a little experiment from there. Treat this as you would if you were an engine tuner instead of a Air file tuner. How do you increase engine power up to 400 or 450 when you have a basic 350 HP turbocharged engine???
1. You already know you can't change the dimensions (no boring or stroking the engine).
2. You can't raise the RPM. 2700 RPM is going to be the limit.
3. Friction reducers such as Roller Lifters and Roller Rockers are not going to actually gain you any noticeable power. Figure if you get more than about 5-10 HP, you will be lucky.

You need to probably replace the fuel pump to something with much greater capacity and pressure capability, maybe increase the fuel injector size and duration. If it is already a turbo engine, I am not convinced a cam change will help much.
The important thing is that you probably will need to replace the Turbochargers with something bigger to increase the boost (Manifold Pressure).
When we are just flight simmers, all we really need to do is mess with the Manifold Pressure limit.
Try this out and see what you come up with. Raise the Manifold Pressure perhaps 1/2 inch at a time and do a quick engine power test at 500 Feet and note it down in a data table. See what it takes to get up to 400 or 450 HP.
When you get that list, how do those number compare to real engines that need ADI and ones that do not?

- Ivan.
 
Hi Ivan,
I remember my old BMW 2.4 Turbodiesel I had until 4 years ago. It was the first Turbodiesel that BMW built (1985), and the 6-cylinder inline engine delivered 115 Hp. There was also a model with a non-turbo diesel version of the same engine, delivering 85 Hp, 30 Hp less, i.e. two thirds of the power of the turbodiesel, so I can well understand what a turbo supercharger can do for an engine.

So regarding the manifold pressure increase for the 400 Hp engine.

Leaving all else the same, (Boost Gain still at 2.34), my first max. MP increase trial was +1.2 MP (from 39.5 to 40.7).
- At 500 ft through 5500 ft, this gave increases of 16 Hp and 4.4 mph.
- It also shifted critical altitude downwards by 1000 ft.
- At critical altitude, there were 13 hp and 1.2 mph increases, and
- at 17500 ft, performance was identical to the previous performance with 39.5 max. MP.

Thus, instead of having 401 hp and 382.2 mph at 500 ft, there are now 417 hp and 386.6 mph,
and instead of having 420 hp and 401.7 mph at 5500 ft, there are now 436 hp and 406.3 mph,
which personally suits me fine now, as I like it more than before. Further increasing it I think would not be very realistic for the N777XT.

Then I increased MP by an extra 0.5 Hg, and got an increment of 7 Hp and 2 mph. This means increments of 14 Hp and 4 mph per inch of MP.
So, to bring our 401 Hp engine to 450 Hp, we would need 3.5 extra inches of MP. As we already had 401 Hp with 39.5 Hg, so with max. MP at 44 Hg, we would get 450 Hp. The sim, in effect, gives 460 Hp with max MP at 44 Hg. Would that be Ram effect, perhaps?

Anyway, I´m falling asleep on the computer. Perhaps tomorrow I´ll do the table with increments of 0.5 inches MP.
What this has to do with engines needing ADI or not, for the moment, I fail to comprehend, but for this engine I don´t think it is important.

Cheers,
Aleatorylamp
 
Hello Aleatorylamp,
An interesting thing is that the base model engine on my Wife's Honda Accord is a little tiny 1.1 Liter Turbo engine with a chain drive CVT transmission. It puts out 197 HP. Not bad for 1.1 Liters and this is nothing special for a modern family sedan. The latest Toyota is a couple HP higher. This is the level of power that would surpass a 1960's V-8 engine.

For this exercise, you are starting at the wrong point. You should start the experiment with a 350 HP engine at 39.5 inches Hg.
I am not convinced that 39.5 inches Hg is the correct manifold pressure for 401 HP at 500 Feet. That is the point of this experiment.

- Ivan.
 
Hello Ivan,

OK, I was just making sure that this time it was 350 Hp to start this 2nd exercise with. It won´t take us to 450 Hp, only to a bit over 400.
I suppose we are not testing with max. MP above 44 Hg.

So: We have our old 350 Hp TIO-540 engine at 500 ft, starting with max. MP 39.5, Torque and Friction Graphs adjusted for 350 Hp, and with Boost Gain 2.34 but probably irrelevant, and Cd0 at 0.013.

This is what I got:
MP 39.5 hg: 350 hp, 357.6 mph, 37.0 prop
MP 40.0 hg: 357 hp, 360.1 mph, 37.5 prop
MP 40.5 hg: 363 hp, 363.0 mph, 37.9 prop
MP 41.0 hg: 370 hp, 365.0 mph, 38.3 prop
MP 41.5 hg: 376 hp, 365.6 mph, 38.6 prop
MP 42.0 hg: 383 hp, 370.2 mph, 39.2 prop
MP 42.5 hg: 389 hp, 377.0 mph, 39.8 prop
MP 43.0 hg: 396 hp, 380.4 mph, 40.1 prop
MP 43.5 hg: 402 hp, 382.5 mph, 40.2 prop
MP 44.0 hg: 409 hp, 394.4 mph, 40.3 prop

It looks like the 0.5 Hg increments provide 6-7 extra Hp, and normally 2-4 extra mph, although there is one 0.6 mph increment, another of almost 7 mph, and the last one of almost 12.

Update:
I was wondering if a next possible exercise could be setting Torque and Friction graphs to get 450 hp at 500 ft with 44 Hg as a starting point, and then working downwards in 0.5 Hg steps to 39.5 Hg, to see what MP comes out for 401 Hp.
P.S. In my Post #175, it was not very clear, but the trial I did was with Max. MP at 40.7 Hg, and the performance increases mentioned were with Max MP at 40.7.

Cheers,
Aleatorylamp
 
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Hello Aleatorylamp,
You STILL can't seem to understand the point of the exercise!!!
For this exercise, you DO NOT mess with the Torque and Friction graphs. That is what has been getting you into trouble.
You should take it AT LEAST to 450 HP and up to 500 HP if you have the patience.
This is for you to figure out what the real engine tuners had to deal with. It is NOT ANOTHER EXCUSE TO SCREW with the Air File to come up with Torque and Friction numbers that are not going to make sense in the long run.

I am not really interested in what numbers you are getting with 40.7 inches MP because I don't think how you got there actually makes sense. This exercise was supposed to give you some insight into what level of actual manifold pressure it might REALLY take to get to 450+ HP.

When I asked you earlier why you were using Water Methanol Injection, the correct answer was: Because the manifold pressure was getting into the range in which the engine might experience detonations without ANTI DETONANT INJECTION.

You are thinking too much about Air Files. You need to think about engines and what is reasonable there.

- Ivan.
 
Ivan,

In your Post#176, you said "You should start the experiment with a 350 HP engine at 39.5 inches Hg.", and now you say: "It is NOT ANOTHER EXCUSE TO SCREW with the Air File to come up with Torque and Friction numbers that are not going to make sense in the long run."

I am NOT LOOKING FOR EXCUSES TO "SCREW" with the Air File. YOU WANTED a 350 Hp engine at S.L. again, so now you tell me HOW THE HECK ELSE am I to get this bugger down to that power again WITHOUT "SCREWING" with the Torque and Friction Graphs ???

HOW do you expect to get 350 Hp from an engine that has Torque and Friction Graphs set already for 402 Hp at 500 ft??? I would think that the whole point of having these graphs is to set required HP.

If you are so sensitive about the Torque and Friction Graphs, YOU tell me what values YOU WANT to have in them. There are only a few columns in each graph anyway, so it won´t put you out too much.

Then you added: "When I asked you earlier why you were using Water Methanol Injection, the correct answer was: Because the manifold pressure was getting into the range in which the engine might experience detonations without ANTI DETONANT INJECTION."

NO, that was not the reason! AS I ALREADY SAID, all I wanted was to separate 5-minute Take-off power into F10 to prevent abuse of full power, and WEP Type 2 is the only option that won´t destroy the whole engine - it only destroys the supercharger if abused.
However, I am currently NOT using WEP type 2 any longer for these exercises anyway.

BTW: Can you hear the detonations in CFS???

Then you said "I am not really interested in what numbers you are getting with 40.7 inches MP because I don't think how you got there actually makes sense. " So WHY did you say it is MY guess regarding what max. MP to put in for a 401 Hp at S.L. engine? I mentioned that I had tried higher values than 40.7 that proved to be excessive for the performance we expected. Take into account that you had already said 39.5 Hg was insufficient.

Aleatorylamp.
 
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Ivan,
In my Post #177, the speed in the last test result line is wrong. Instead of 394.4 mph it should read 384.4 mph, and then, the explanatory comment regarding a 12 mph increment is also erroneous.

So, I suppose we ARE testing above 44 Hg Manifold pressure then...
Anyway, here´s the continuation of the Manifold Pressure variance table exercise, now taking it up to 500 Hp, like you said.
It is done with the same Torque and Friction graphs that were screwed with - sorry, modified - in order to lower S.L. Hp to 350 hp again, with 39.5 Hg, for the purpose of this exercise, which started in Post #177.
Perhaps you can still tell me which other way I should have done it to get the required 350 Hp with 39.5 Hg back again without messing with Torque and Friction graphs...

MP 44.5 hg: 415 hp, 386.6 mph, 40.5 prop
MP 45.0 hg: 422 hp, 388.0 mph, 40.6 prop
MP 45.5 hg: 428 hp, 389.8 mph, 40.7 prop
MP 46.0 hg: 435 hp, 391.6 mph, 40.9 prop
MP 46.5 hg: 441 hp, 393.4 mph, 41.0 prop
MP 47.0 hg: 448 hp, 395.2 mph, 41.1 prop
MP 47.5 hg: 454 hp, 395.4 mph, 41.2 prop
MP 48.0 hg: 461 hp, 395.4 mph, 41.2 prop
MP 48.5 hg: 467 hp, 396.2 mph, 41.3 prop
MP 49.0 hg: 474 hp, 397.9 mph, 41.5 prop
MP 49.5 hg: 480 hp, 399.6 mph, 41.6 prop
MP 50.0 hg: 487 hp, 401.3 mph, 41.7 prop
MP 50.5 hg: 493 hp, 403.1 mph, 41.8 prop
MP 51.0 hg: 500 hp, 404.8 mph, 42.0 prop

One thing that strikes me as obvious here, is that the first part of the exercise increased mph by 26.8, and the second part, only by 18.6 mph, but this is logical because of air resistance rising in a geometrical progression, and power rising in an arithmetical progression, causing a progressive loss in speed gain for each increment of 0.5 inches of mercury manifold pressure.

Aleatorylamp.
 
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