Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: fscott on February 12, 2001, 11:08:00 PM
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Let me get my point across quickly and right to the data.
Flying the Niki makes you fell like it is being *jerked* around by the thrust of its engine, rather than the plane's weight determining holding back it's maneuverability. Get what I mean?
These numbers represent pounds per one horsepower. Obviously the higher pounds per horsepower, the worse the plane performs.
1 - Empty weights could be slightly different in some cases, but only marginally if not accurate.
2 - Weight does not include fuel load, ammo, etc.
3 - Horsepower is taken from maximum setting, including wep. Again some may have different numbers but it should be close if not accurate for most of these.
4 - These numbers alone do not represent propellor efficiency, wing loading, all of which affect an aircraft's ability to climb, dive, and it's general performance.
Nik1-J2:
5858 lbs
1990 hp
2.95 lbs/hp
A6m5c:
3920 lbs
1130 hp
3.47 lbs/hp
J2m3:
5675 lbs
1820 hp
3.12 lbs/hp
Ki84:
5864 lbs
1900 hp
3.09 lbs/hp
Yak9u:
5100 lbs
1650 hp
3.09 lbs/hp
Spit9:
5610 lbs
1660 hp
3.38 lbs/hp
P51D:
7125 lbs
1590 hp
4.48 lbs/hp
F6f5:
9042 lbs
2200 hp
4.11 lbs/hp
The Niki with 2.94 pounds per every horsepower. Now, could this explain why the Niki does what it does? It is basically being tossed around the sky in whatever direction the pilot wishes. I was amazed that it even has better lbs/hp than the Yak9u. I threw in the J2m and the Ki84 just to show that we will see more from where the Niki came from.
fscott
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Figures without fuel and ammo load are unfurtunatly useless. Think about it how little extra weight is added to lightly armed and small fuel capacity Yak9, compared to huge fuel capacity and 800+ rds of heavy 20mm in a niki or chog. So numbers in poor comparison are not applicable to our sitiuation. We need to examine the FM of this thing in detail to find out whats wrong, too many ppl notice it. Look at e retention and vertical performance of niki.
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fscott your headed in the right direction but GUNHERZ has a good point. If you can find the data that compare thrust to loaded weight of the AC's you will have it nailed. Try to find trust figures they are the real story. A plane like the F8F for example had a thrust to weight ratio greater than 1:1. That means that you could stand a F8F on the vertical and it would ACCELERATE STRAIGHT UP! That's wicked for a prop driven fighter.
[This message has been edited by Jimdandy (edited 02-12-2001).]
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Three quick points:
1) I did not intend this to be a flame war.
2) People will ignore their own intelligence and argue the same old opinions, if anything less than a divine revelation is brought to their attention.
3) GRUNHERZ, lets take your example then. Add 200 pounds to the yak weight, and add 800 pounds to the niki weight. These are just guesses. Look what happens. You get 3.21 lbs/hp for the Yak and 3.31 lbs/hp for the Niki. Still, you are talking relatively close numbers even adding 800 pounds to the niki. Even with 800 more pounds added, the Niki still is less than an empty Spit9. I'm sure these added weights are too little, but the point is, even if the Niki has 4x the added weight, it still remains excellent in lbs/hp when compared to all other fighters.
Someone with EXACT added weights of ammo and fuel could help here but HORSEPOWER is the most defining factor here.
fscott
[This message has been edited by fscott (edited 02-13-2001).]
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Fscott I can't verify all of your figures right now but your argument is flawless. The N1K2 does indeed have superlative thrust to weight ratio at low fuel loads, and thrust to weight ratio is how you make a "UFO", as the ACM-challenged like to call it.
[This message has been edited by funked (edited 02-13-2001).]
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Fscott- the Yak-9U is a bad comparison- it's good vertical performance is design not specifically power. It's Vk-107 motor actually only makes a relative 1500 hp at SL. Thats pathetic compared to radial's.
Better to compare radial planes like an F4U, F4F and La-7 or 190A-5 (A-8 is obviously too heavy).
Strip the ammo and fuel out of these planes and, surprisingly enough, they all have incredible hp/wieght ratios.
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If your in range, so is the enemy.
(http://www3.bc.sympatico.ca/sorrow/sorrow.gif)
[This message has been edited by Sorrow[S=A] (edited 02-13-2001).]
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A plane like the F8F for example had a thrust to weight ratio greater than 1:1.
LOL! Yeah, sure it did! (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
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Like an F-15 you mean? Hope PYRO will perk the F-15.
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Fw190A5:
weight unloaded 2900Kg: 6380lbs
engine power:1800hp
W/P: 3.54
Fw190A8:
weight Unloaded 3450kg: 7480lbs
Wngine power:1900hp
W/P: 3.9
2.98lbs/hp------->3.54lbs/hp
Oh, good difference, but doesnt explain why one is an UFO (according to Funked I'm an ACM challenged (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)) and the other not.
Ah, and BTW, where is that 2000hp engine torque?...I used to think that when one has a big prop that converts sheer power into thrust (as the n1k2 has), and a low mass like the N1K2 has, then one experiences one strong thing called "torque", that, between all the planes above put, in the N1K2 should be the biggest.
Where is it?
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I agree with Fscott and Funked that for comparison purposes, its best too look at "empty" weights.
Loaded weights are not good comparison points, due to the fact that they are variable over time (in combat), and subject to change depending on how the pilot loaded the aircraft initially. And these make a huge difference in combat.
For example lets look at the N1K2, that everyone is so fond of discussing.
The N1K2 is an extremely long range fighter. I forget the exact range (working from memory), but I believe it is somewhere in the 1200 mile range, which puts it in the same class as the P51, or considerably more than twice the range of your standard Yak-9U.
In the Yak I typically take 100% fuel (I like to climb to 20k and then fly long missions), and its easily enough fuel to fly most arena missions. But I would bet that most N1K2 pilots take only 25%+DT for their missions of base defense or furballing. So when you engage most N1K2's they are relatively "fuel light" in comparison to a fully loaded takeoff weight.
So if you use loaded weights for comparisons, you will significantly undervalue the effectiveness of the N1K2, because you are fighting an aircraft that is comparitively much lighter.
This will then lead to cries of "UFO" because the actual performance disparity will be much higher than you expect.
"Empty Weights" are the way to go in discussions like this.
Edit: RAM while I won't argue the torque issue with you (I believe your correct to a certain point), I will point out that "lack of torque from a 2000hp engine" is something that effects most, if not all of the aircraft in AH at the current time
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Vermillion
**MOL**, Men of Leisure
[This message has been edited by Vermillion (edited 02-13-2001).]
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Originally posted by Vermillion:
Edit: RAM while I won't argue the torque issue with you (I believe your correct to a certain point), I will point out that "lack of torque from a 2000hp engine" is something that effects most, if not all of the aircraft in AH at the current time
I could not agree more with you (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Originally posted by fscott:
Nik1-J2:
5858 lbs
1990 hp
2.95 lbs/hp
I believe that there is a real problem using 1,990 hp for this engine. No Homare (I believe that this was the engine, I'm in the office and have no references here)ever made that much power on 87 octane avgas. I would estimate that the power available never exceeded 1,400 hp.
Here's what I'll do tonight: I will calculate the available hp based upon the N1K2's drag numbers and its known maximum speed, using full combat weight as the baseline. I'd wager large that this produces power numbers in the 1,400 hp range.
I'll post my findings on the BBS. I won't get to this until this evening at the earliest, so be patient. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
My regards,
Widewing
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Originally posted by Jimdandy:
fscott your headed in the right direction but GUNHERZ has a good point. If you can find the data that compare thrust to loaded weight of the AC's you will have it nailed. Try to find trust figures they are the real story. A plane like the F8F for example had a thrust to weight ratio greater than 1:1. That means that you could stand a F8F on the vertical and it would ACCELERATE STRAIGHT UP! That's wicked for a prop driven fighter.
[This message has been edited by Jimdandy (edited 02-12-2001).]
fscott I wasn't trying to flame you at all. As I said I think you on the right track. The only reason I suggest looking a the thrust to weight ratio is that it takes into account the ability to put the horsepower to use. You might say it accounts for the prop and the power to weight ratio. Just to give an example. If you have a 4000hp engine in a top fuel dragster and put bicycle tires on it it will never be able to put all that horsepower on the road. It will just spin the tires. You put big fat sticky drag slicks on it and it will fly down the trak. The prop on the engine is the way the horsepower is used to move the plane like the tires on a car. If you put a Piper Cub prop on a Bf 109 it will not perform like it does with the right prop. Some of the biggest advances in the performance in WWII aircraft were made by just putting on a better prop. Your on the right track just a small addition to the data will make your argument perfect. I bet the thrust to weight ratio of the N1K is excellent.
Vermillon the problem with empty weight is one many Army and Navy people found out early on when going out to buy a new aircraft. There are many cases where a great prototype made for a poor fighter because after they added the combat weapons the thrust to weight went to hell and they had a pig on their hands. A stripped down B17 will perform fantastically. Add all the 50's fuel and 6,000lbs of bombs and it's a tank. The way I have always compared aircraft was in a "clean" configuration with an agreed upon standard internal weapons load and fuel allocation. Here is an example of what can happen when the guns are changed on a plane and why you have to look at some type of weapon and fuel load or you get an unrealistic picture of what the plane will do in combat:
The Mitsubishi J2M started out as a pretty good performer then they added 4 20mm cannon. The addition of the guns restricted the performance of the plane so much that it no longer met the original demands so they added a turbocharger and it still wouldn't reach the B-29's. So they added upward firing 20mm cannon.
[This message has been edited by Jimdandy (edited 02-13-2001).]
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can you post the 109's info mainly the 109f, maybe with and w/o gondolas?
thx
Eagler
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Careful Widewing (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Your now delving into the same issues we have discussed repeatedly about the N1K2, the Ki84, and the Homare engine, and were the reasons I was looking for the post war US test documents for that bird.
I will certainly be interested in seeing what you come up with.
FYI Wells, Myself, and several others looked at the same issue, and came up with the opinon that the N1K2 at the stated horsepower of 1990hp, should easily be a 400mph plane.
Another bit of pertinent data I saw from a friend that lived in Japan, stated that he had documents that said that the official "top speed" that is typically published for the N1K2 (360ish? I forget exactly) was indeed taken with 87 octane fuel and in that particular set of flight tests, the engines were never set to full power. I'm paraphrasing, but the engines were run at what we would consider "Normal Cruise Power", and not at "Takeoff/Emergency Power", let alone at "WEP". I asked him to provide a copy to me, but unfortuneatly they were in Japanese, and he never sent them too me. Supposedly, he got the information (copies of originals from the Japanese War Ministry) from a Gentleman in his late 80's who actually flew the N1K2, but of course I couldn't confirm or deny any of it. But I will say that the person who claimed to have this, was not the type of personality that would leave me to believe that he was lying.
Just some more information for you.
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Vermillion
**MOL**, Men of Leisure
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Jimdandy, the problem with a "an agreed upon standard internal weapons load and fuel allocation" is that they can mean very different thing depending on the aircraft and what it was designed for.
If you decide your standard is %50 normal fuel loads, this can literally mean the difference in hundreds of gallons of fuel, depending on if the design of the aircraft is a long range fighter escort (ie P51's) and a short range air superiority fighter like a Yak-9U.
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Vermillion
**MOL**, Men of Leisure
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Verm the fact is as I showed above there has to be an agreed upon standard. A plane can and will perform differently with guns and fuel in it. It wouldn't reflect anything close to a combat power/wieght ratio if you look at empty weight. Planes don't fly with no guns, armor, fuel, and oil in them. The standard I gave above is what I think is used. Any combat analyst would be lax in his duty if he didn't look at some kind of "norm" that would be expected to be seen in combat. Look at Westys post on the F8F. They guy talks about how much better the plane performs in the stripped down "civilian" version.
[This message has been edited by Jimdandy (edited 02-13-2001).]
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Please don't sway away from the original data. If you load one plane with weapons and fuel, then you have to do that with all planes. When you do this you see that the Niki still maintains nearly the best lbs/hp.
A plane with lower lbs/hp will accelerate better in snap turns and climbs.
Ram, I don't see your point comparison? The Niki gets thrown around the sky because it has more horsepower per weight, does this not make sense? 2.9 lbs to 3.5 lbs will have a huge impact on handling.
Personally, I'm convinced when I did these numbers last night. I *think* the general feeling among the whiners, is that the Niki is a big radial aircraft that should handle like a Hellcat, when the real truth is that it is a very light aircraft with a very powerful engine. I feel sad for them when the Ki84 comes to play.
fscott
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Originally posted by fscott:
Ram, I don't see your point comparison? The Niki gets thrown around the sky because it has more horsepower per weight, does this not make sense? 2.9 lbs to 3.5 lbs will have a huge impact on handling.
Hehe, Fscott, I was simply posting the 190A5 and A8 comparison, the "UFO" part was only included to add a nice (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif) to the "ACM challenged" comment by funked.
IMO the problem with the N1K2 is not so the good acceleration it has, but the lack of torque and the incredible E-retaining it has that allows it to turn 180º,zoom, and catch a plane that just bounced it. And dont tell me that this accounts for the acceleration ,because I have seen N1K2s doing it against 109G10s, and the powerloading of the 109G10 is the best of all the planes in this game.
other than that, I like this thread, its quite informative (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
[This message has been edited by RAM (edited 02-13-2001).]
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Originally posted by fscott:
Please don't sway away from the original data. If you load one plane with weapons and fuel, then you have to do that with all planes...
fscott
fscott I'll say it one more time. I'm not disputing your data. I'm sure the power to weight ratios are right. As I said it's the thrust to weight ratio that is the truer measure of performance. Even if you ONLY look at empty weight (and that's fine as long as we look at all of them empty) the thrust to weight will tell you more. I'll give one more example. Put a 4000 horse power dragster on Ice with slicks. It isn't going any place. All of that horsepower will just sit there because of the lack of friction and thus the lack of thrust. A more efficient prop will "grab" the air better and generate more thrust with the same engine. Look at it this way. Take the pop off of the plane. You can run that engine at max rpm all day long. It will still be capable of producing max horsepower but that plane isn't going any where because without the prop it can't generate thrust. Any way that's enough. You should be able to see what I mean. You are very close to being exactly right and if you find the thrust to weight ratios some place it may turn out that there is no denying the N1K. As it is now it appears you maybe right. Your on the right trail don't stop now.
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Jim your looking at "civilan-ized" versions of the data then, because "empty weights" include armor, guns, and oil.
They only lack fuel and ammunition.
And as I pointed out, fuel loads, especially if you state it as a percentage of total regardless of type, is wildly inaccurate. Plus it changes both before and during the flight. Ammo is the same way.
Now if you want to state the fuel loads as a component of distance, ie X gals of fuel to fly a range of 500 miles, and calculate the required fuel and weight, then I might start to an agreed upon standard. But otherwise it is fatally flawed.
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Vermillion
**MOL**, Men of Leisure
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Widewing you can also get a power estimate from the rate of climb. (I get about 1800 hp). If you say it only had 1400 hp then you are disputing the climb data as well as the power figure.
Be sure the drag figures you use weren't based on speed data in the first place.
[This message has been edited by funked (edited 02-13-2001).]
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Jimdandy, no WW2 fighter had any where near 1:1 thrust:weight.
Also you're going to have to show me a plane that had a big performance improvement just from a prop change. There is a lot of talk but not much engineering data in this area.
[This message has been edited by funked (edited 02-13-2001).]
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Originally posted by Vermillion:
Jim your looking at "civilan-ized" versions of the data then, because "empty weights" include armor, guns, and oil.
They only lack fuel and ammunition.
And as I pointed out, fuel loads, especially if you state it as a percentage of total regardless of type, is wildly inaccurate. Plus it changes both before and during the flight. Ammo is the same way.
Now if you want to state the fuel loads as a component of distance, ie X gals of fuel to fly a range of 500 miles, and calculate the required fuel and weight, then I might start to an agreed upon standard. But otherwise it is fatally flawed.
No Verm the civilized version was an example of one lacking the guns and ammo so it flies better.
Of course I'm talking about some kind of fuel load at a given range and alt that you you expect to encounter the aircraft. That is why I said "...Any combat analyst would be lax in his duty if he didn't look at some kind of "norm" that would be expected to be seen in combat..." Meaning that if your putting fighters up in a bomber escort mission for example what would you try to predict what you would encounter for enemy aircraft. The combat analyst job is to try to predict combat situations. So he would make some estimate of the type of aircraft, armament load, and fuel load they would have in the encounter for both sides. I assumed I will admit that empty weight was done as they do with a car and that means without fluids. It reflects a shipping weight. If you say that that isn't how they do it for aircraft I'll take your word for it. You can use the empty weights to evaluate the aircraft all you want. It still will not give an accurate account of the plane you will encounter. There is no way. But there are better ways than just looking at the empty weight. A plane has a radius of operation. You can assume it will limit itself to one that will return it home. Thus it will fly to it's "normal" operational alt and will have X amount of time for patrol or what ever. So you will more than likely encounter the plane with the fuel left in it to reach operational alt and a full load of ammo for a best case scenario for a clean aircraft. That will be the one that performs the best and the one you want to be most worried about. If it's loaded with bombs and rockets well... I would do my calculations based on what I said above on 50% fuel and a full load of ammo. No external weapons, bombs, or drop tanks. A plane loaded is a plane at a disadvantage in a dogfight. You could then evaluate it at all altitudes based on those criteria. If a P-51 holds more gallons of fuel than a 109F-4 at 50% fuel it's still a fair comparison. They both have the expected amount of fuel. This is only an example but you see what I'm getting at. All your doing is trying to get a better "feel" for what your opponent will be like. The only plane you will encounter with no ammo and fuel will more than likely be on the ground don't you think. And if he his very low on fuel and out of ammo it's not much of a threat now is it?
[This message has been edited by Jimdandy (edited 02-13-2001).]
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109 E7 (don't have weights for F, sorry)
Engine: 1,200 Hp
Weights: Empty 2014Kg (4,440 Lb); Max Take-off 2767 Kg (6.100 Lb).
This would make the HP per LB empty: 4,440/1,200 = 3.67
Less guns in the F4, 1x20mm and 2x7.99mm while the E7 had 1x20mm and 4x7.9mm and F version had a bigger engine. F probarly weighted a bit more.
(http://saintaw.tripod.com/jg5wilbus.gif)
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Rasmus "Wilbus" Mattsson
III/JG5 "EisMeer"
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One last time and then I will stop saying this. Thrust to weight ratio. Look at the thrust to weight ratio. That engine with 1000hp isn't doing a damned thing without a prop. The more efficient the prop the better the horsepower will be put to use. Any plane with a thrust to weight ratio greater than 1:1 will accelerate in the vertical. THRUST/WEIGHT (THRUST divided by WEIGHT). They didn't put those paddle bladed props on the P-47M and the P51H for no reason.
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Jimdandy the problem with your argument is that all of the planes in our sim had prop efficiencies that were in a pretty narrow range. Thrust:weight comparisons boil down to power:weight.
And I still don't know why you are talking about 1:1 ratios in the context of WW2. None of these planes were even close to that.
[This message has been edited by funked (edited 02-13-2001).]
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Jim, I would agree with you if the pilots in AH flew in a mission oriented or scenario environment, for instance P-51's always flew escort, or P-47's flew ground attack over the continent. Then yes, you could get a very good feel for the aircraft that way.
But thats not the way it works in AH, its a total free for all.
Pilots just go do what they want, with little regard for dying or completing a mission, as long as they feel they are hurting the enemy. For instance base defenders launching time and time again in minimum fuel N1K2's, fighting till they die or run out of fuel and launching again. They do this because they can, with little to no adverse effects. Why worry about possibly running out of fuel, if you can instantly respawn into the fight, and in the meantime you have shot down or damage two enemies who now have to fly another 10 minutes to attack your base.
My point is that the MA is not real life, and you can't accurately predict what fuel state or armament loadout an enemy is carrying at any time.
If regards to our discussions of weight, if you own AHT you can look at the weight breakdowns for "empty" or "loaded" weights, or you can also do the same at the naval aviation website to see flight test data that will explain the issue.
Here: http://www.history.navy.mil/branches/org4-8.htm (http://www.history.navy.mil/branches/org4-8.htm)
I do see your arguements, but neither way is perfect, and for a comparitive look at fighters I prefer the empty, because fuel loads have too great an influence on such numbers.
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Vermillion
**MOL**, Men of Leisure
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Originally posted by funked:
...And I still don't know why you are talking about 1:1 ratios in the context of WW2. None of these planes were even close to that...
[This message has been edited by funked (edited 02-13-2001).]
What I understand is that the F8F was over that. A P-51H was getting close from what I understand. Give me a break. If you know that much about it than you know I'm still right. It is the thrust to weight ratio. If comparable to the power to weight ratio wonderful. But thrust moves the plane. You can generate all the damn horsepower you want with that engine but that plane isn't going anywhere without the thrust generated by the mass flow produced by the prop. On top of that it I was talking about what the numbers were telling you. It's important I think to give someone a feel for what the numbers are telling them. You can punch numbers in a calculator all day but do you know what they mean. Because I'm writing to a general audience here and not a bunch of engineers I try to put it as simply as I can. Understand? Thanks for you interjection.
[This message has been edited by Jimdandy (edited 02-13-2001).]
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Gents,
We are all forgetting about one other huge factor affecting performance that is even more important than Thrust to weight.
DRAG
The NIK2 is a poor example because the performance, ie top speed is in doubt. But take two similar A/C and compare and you find out what the Thrust,weight and Drag ratio is and you get a better idea of how well an A/C could accelerate and pull UFO type maneuvers would be. Here is an example.
P51D
HP=1720 at sea level where air density is a constant.
Empty Weight= 7205lbs
Power to weight = 4.2 Rounded
Max speed at sea level = 370MPH
FW190A-5/U8
HP= 1755
Empty Weight= 6716lbs
Power to weight= 3.8 rounded
Max speed at sea level = 335MPH
So despite an edge in Power to weight ratio the Drag factor significantly reduces performance of the FW190A-5 relative to the P-51D. It is smaller and lighter, higher wing loading and more HP but still cannot come close to the performance envelope of the P-51D.
So take another hard look at the NIK2 before declaing it uber. It's top speed at sea level is no better than the F6F a very high drag airframe, even with less weight, better power loading and nearly a 2,000HP engine. It has a number of things that hold it back in performance numbers such as Fuel, lack of hyper-accurate data etc. however it cannot be said that this A/C exceeded the abilities of it's contemporaries based on what information is available.
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Thank you F4UDOA. I'm glad to see someone else is thinking beyond hp/wt. Your right. Drag will greatly effect the plane. It increases with the square of the speed. So at lower speeds the planes thrust to weight ratio is very telling. This argument was started with low speed loops so I didn't worry about the drag to much. But thank you for pointing that out. So if I make a simple drag formula it would look like this:
F=KV^2
where K is a proportionality constant for the shape (frontal area) of the aircraft, F is the force of the liquid (in this case air), and V is the velocity of the aircraft. So lets just play with the numbers. Lets say our plane has a known drag of 1000lbs at 200mph. K=0.025lbs/mph. Now lets look at it at 400mph. F=4000lbs. The force really starts to increase with speed. That would also tell you that if you have 4000lbs of thrust generated by your aircraft you are at terminal level flight velocity. Your not going an faster than 400mph with out diving. Those are made up numbers just to show you where the formula takes you.
Edit: I made a mistake. The constant K should be 0.025lbs/mph^2.
[This message has been edited by Jimdandy (edited 02-13-2001).]
[This message has been edited by Jimdandy (edited 02-13-2001).]
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You forgot about induced drag. But that equation you have will work at high speed.
[This message has been edited by funked (edited 02-13-2001).]
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use this http://www.iit.edu/~buonmic/aircraft_test.xls (http://www.iit.edu/~buonmic/aircraft_test.xls)
only thing wrong in that spreadsheet is the prop efficiency stuff, which i made up
if you have real prop efficiency curves, gimme gimme gimme
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Thanks Zig, I forgot about that thingy!
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The N1K2-J used the same basic wing design as the A6M5 52 B, the later Zero's with the increased skin durability for faster dive speeds. The only real change in aerodynamic surfaces between the two are from the N1K2's ailerons and vertical stabilizer, the N1K2 aileron's are quite a bit shorter to utilize the butterfly flaps, and are hinged deeper in the wing. The N1K1-Ja and A6M5 used the exact same tail design, while the N1K2-J had a larger horizontal stabilizer and full length rudder to compensate torque better.
So if your looking to input wing data try what's available for the A6M5 and A6M6's with increased wing skin. Keep in mind the Zero's wing wasn't what limited it's diving speeds, the ailerons of the A6M2's and A6M5's were designed for under 200 mph flight, alot of the high speed control problems were solved with the clip winged A6M3 but manuverability apparently suffered. Of course the numbers won't be exact but using figures for the Zero's wing you could probably get very close in general ability, at least over the point where the flaps were deployed
Below 250 mph or so (I'm not sure what speed they came down at in level flight, since it was also AoA dependent) the N1K2 was an extremely unclean airframe, the butterfly flaps added alot of induced drag when they deployd. I believe this was the main reason for such a high powered engined intially, to offset the drag in it's manuvering envelope. Or actually a side effect, because it was originally to give a float plane near equal speed of the Zero fighter, the only way to do so with so much drag present.
Once the flaps are deployed, your going to see a great increase in wing area, lift, and drag, and I have no idea what the aerodynamic data would come out to with them deployed...it would probably go a long way towards offsetting it's power to weight ration though.
- Bess
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Here's some numbers I pulled off Joe Baugher's (http://www.csd.uwo.ca/~pettypi/elevon/baugher_other/n1k.html#RTFToC4) page:
Powerplant: NK9H Homare 21 18-cylinder radial rated at 1990hp for takeoff, 1825hp at 5740 ft, and 1625hp at 20,015 ft.
Performance: 369mph at 19,355 ft, 359 at 9,840 ft. Cruising speed: 230mph at 9,840 ft
Service ceiling 35,300 ft
Climb to 19,685: 7 min 22 sec
Range: 1066 miles 219 mph at 9840 ft, max range is 1488 miles w/drop tank
Weights: empty 5,858 lbs, loaded 8,818 lbs, max 10,714 lbs.
Dimensions:
Wingspan: 39 ft 4 7/16 inches
Length: 30 ft 7 29/32 inches
Height: 12 ft 11 29/32 inches
Wing area: 252.95 sq ft
Reading through the page it turns out only 60 were delivered by the end of 1944. 415 total were produced by war's end.
[edit] Some notes Mr Baugher has on the N1K1-J:
Since the Homare 11 had been accepted for production before the completion of its final tests, it was plagued with teething troubles. The early Homare engine failed to develop its rated power, the propeller torque during takeoff was excessive, and the visibility during taxiing was poor. However the aircraft had pleasant flying characteristics and the automatic combat flaps gave the aircraft exceptional maneuverability.
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Flakbait [Delta6]
Delta 6's Flight School (http://www.worldaccessnet.com/~delta6)
Put the P-61B in Aces High
"With all due respect Chaplian, I don't think God wants to hear from me right now.
I'm gonna go out there and remove one of His creations from this universe.
And when I get back I'm gonna drink a bottle of Scotch like it was Chiggy von Richthofen's blood and celebrate his death."
Col. McQueen, Space: Above and Beyond
(http://www.worldaccessnet.com/~delta6/htbin/delta6.jpg)
[This message has been edited by flakbait (edited 02-13-2001).]
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Originally posted by funked:
You forgot about induced drag. But that equation you have will work at high speed.
[This message has been edited by funked (edited 02-13-2001).]
Gee funked thanks. As I said if I were only discussing this with engineers I would go a bit deeper. There is a large audience reading this so a gave a simple equation that would demonstrate it sufficiently as I stated. Did you read it closely. No or you would have caught the dimensional analysis mistake I made. I'll let you tell them all about Bernoulli's equation and vortex shedding etc. I'm just trying to KISS it. Your great at making little comments let's see you take it over and blow me away with your fluid mechanics. I'm no expert so have at it.
[This message has been edited by Jimdandy (edited 02-13-2001).]
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Originally posted by funked:
Widewing you can also get a power estimate from the rate of climb. (I get about 1800 hp). If you say it only had 1400 hp then you are disputing the climb data as well as the power figure.
Be sure the drag figures you use weren't based on speed data in the first place.
(Please excuse any typos. This online format makes it a pain in the neck to review a post prior to clicking 'send')
I have not been able to locate specific drag numbers for the N1K2. However, we can make some well founded judgements based upon aircraft of similar size and configuration, for which, I do have data.
To begin, once you know the drag coefficient of the aircraft, you can calculate the flat plate area.
Cdo = Drag Coefficient
Sw = Wing area in square feet.
Cdo x Sw = flat plate area.
Now, take the known horsepower and divide it by the flat plate area. This gives us the available HP per square foot of flat plate area, or HP/f.
Let's look at the F4F/FM-1. It has a zero-lift drag coefficient of .0253 and a flat plate area of 6.58 sq/ft. With 1,200 hp available, the HP/f is 182. This allowed for a max speed of about 320 mph.
How about the P-47B? Its Cdo was .0213 (its wing was especially clean and thin) and a flat plate area of 6.39 sq/ft. With 2,000 hp on tap, the HP/f is 313. This aircraft was capable of speeds just over 420 mph.
Now, let's look at the lowly P-39D. Its Cdo was an excellent .0217 and a flat plate area of 4.63 sq/ft. Having 1,150 hp, this provides for a HP/f of 248. Max speed was 368 mph.
Finally, we can look at the N1K2. Based upon camparible raial engine fighters, I will give it a generous Cdo of .0240. We find that the wing area is 253 sq/ft.
So, 253 x .0240 = 6.07 sq/ft.
Let's assume for a minute that the Homare radial actually generates 1,990 hp.
1,990/6.07 = 328 HP/f
That's considerably higher than the P-47B, yet the Thunderbolt is more than 50 mph faster! How can this be? Simple, the Homare was not making anything close to 1,990 hp.
Let's plug in 1,500 hp into the equation.
1,500/6.07 = 247 HP/f.
At this point, let's go back to the P-39D with its HP/f of 248. The P-39D could manage 368 mph. The N1K2 could reach only 369 mph.
Do you see the correlation? Based upon this method, the Homare was making no more than 1,525 hp, which is fully 465 hp less than rated.
This may be a backdoor method of calculating approximate horsepower, but I'll wager large that it stands up well to any other methodology used for the N1K2-J.
Now, as to climb. This is largely determined by weight and power. However, drag is also a critical factor. Let's compare the Bell P-63A and the N1K2.
Normal combat weight for the P-63A is 8,800 lbs. The N1K2 weighs in at 8,818 lbs loaded for combat (no external stores, full fuel and ammunition for both). It takes the N1K2 7.36 minutes to get to 19,685 ft (6,000 meters). The P-63A gets to 20,000 ft in 5.72 minutes. The Bell has only 1,325 hp available. So why does the P-63A climb so much faster than the N1K2 if it has more power and equal weight? The answer is that the N1K2 had much less power than rated. Moreover, the P-63A has much lower drag numbers.
Cdo = .0182
Sw = 248 sq/ft
Flat Plate area = 4.51 sq/ft
HP = 1,325
HP/f = 293
If the N1K2 was making 1,990 or even 1,800 hp, it would climb as well as the P-63A. The fact is that it does not even come close. So,
this tends to support the 1,525 hp estimate.
For JimDandy:
Power is determined by HP and propeller efficiency. Typically the WWII fighters had prop efficiencies in the 80% range, give or take 2%. Based upon this, Francis (Diz) Dean provides a simple formula to determine drag as equalized by thrust.
Thrust (in pounds) = 375 x prop efficiency x horsepower/TAS (true airspeed).
His example is that of a P-40 maintaining a constant 280 mph with 900 hp.
T = 375 x .80 x 900/280 = 964 lbs of drag, which must be equalled by 964 lbs of thrust to maintain a constant speed.
No WWII fighter ever produced thrust equal to its weight. Even the F8F would require over 10,000 lbs of thrust to accelerate straight up. Let's assume he is climbing at
125 mph, and not accelerating.
T = 375 x .80 x 4,500 hp/125 = 10,800 lbs, which is pretty close to weight + drag.
This would allow for a climb rate of about 11,000 ft/min., straight up. This is not out of line for the hotrod F8F that set the time to 10,000 ft record of just under one minute. However, this was a stripped down fighter making nearly 4,000 hp. We know that the production F8F could manage 4,570 ft/min. with 2,100 hp. Surely, it had nowhere near a 1:1 thrust to weight ratio. 1:2 at the very best.
Data sources:
America's One Hundred Thousand by Francis Dean
The American Fighter by Angelluci and Bowers
The Complete Book of Fighters by Green and Swanborough.
My regards,
Widewing
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Thanks Widewing. I must have been the data on that hotrod version I was looking at. I appreciate the explanation. As I said originally my intention was more to show that as the ratio went past 1:1 a plane could accelerate in the vertical. I had wrongly thought that the F8F had a greater than 1:1 but I never thought that it was the norm anyway. I also wanted people to look past the simple hp/wt and see that the prop has to use that power efficiently or the horsepower is wasted. hp/wt is a very good sign of a hot plane but it isn't the end all to making work. You can have a 10,000hp car but if your using smooth steel wheels in ice your not going anywhere.
[This message has been edited by Jimdandy (edited 02-13-2001).]
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Heheh FYI JimDandy (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Most of the people that respond to the techno threads like this, are Engineers of one discipline or another.
Funked, Wells, Niklas, Zigrat, Myself, and I'm sure there are others that I'm forgetting at this exact moment.
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Vermillion
**MOL**, Men of Leisure
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Here's some food for thought. I took film of my little jaunt in an N1K2 loaded with a pair of 551 lbs bombs. Even with an extra 1,102 pounds on board it still handles like a dream.
Niki flight (http://www.worldaccessnet.com/~delta6/htbin/niki.zip)
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Flakbait [Delta6]
Delta 6's Flight School (http://www.worldaccessnet.com/~delta6)
Put the P-61B in Aces High
"With all due respect Chaplian, I don't think God wants to hear from me right now.
I'm gonna go out there and remove one of His creations from this universe.
And when I get back I'm gonna drink a bottle of Scotch like it was Chiggy von Richthofen's blood and celebrate his death."
Col. McQueen, Space: Above and Beyond
(http://www.worldaccessnet.com/~delta6/htbin/delta6.jpg)
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Extremely interesting analysis Widewing. Much food for thought here.
I suppose part of the 'problem' (if one exists) is that we have no real idea how the FM's of the AH aircraft are generated. Let's look to history a little.
Back in the days of AW I understand it used a simple 'table-based' flight model. This enabled the aircraft to hit the right numbers, but basically consisted of a number of lookup tables for the aircraft.
So, a particular aircraft, at a particular weight, at a particular angle of attack with a particular throttle setting and at a particular altitude would generate a specific climb rate.
Now lets fast forward to AH. IF the Nik had more engine power than it should, the AW based system would still let it hit the right numbers for top level speed, climb rate etc. I would imagine that the only place that the incorrect engine power would show up would be in acceleration, vertical performance and the ability of the aircraft to replace lost energy after maneuvering (somewhat similar to E retention).
Now whether the same thing applies here in AH I do not know. But the concept certainly is interesting.
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When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things.
Chapter 13, verse 11
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Originally posted by Vermillion:
Heheh FYI JimDandy (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Most of the people that respond to the techno threads like this, are Engineers of one discipline or another.
Funked, Wells, Niklas, Zigrat, Myself, and I'm sure there are others that I'm forgetting at this exact moment.
Thanks Verm I didn't know that. I still don't think it's a bad idea to KISS on here so those without the background can get some enjoyment out of it. Admittedly there are times where that's almost impossible but I'm sure there are some plane nuts and budding engineers that would like to know so I try to make analogies. What pisses me off is when I make a point of saying things like "...if I make a simple drag formula..." and some know it all pops in and tells me what I missed. Well NS buddy I just said it was simplified. Or ask's me why I'm talking about 1:1 thrust ratios when I'll I said was "...Any plane with a thrust to weight ratio greater than 1:1 will accelerate in the vertical..." Just wonted those that didn't know what the relationship of the numbers meant when they found the data. I think Widewing made a good argument against the N1K using comparative data and some good rules of thumb. It does bring into question the performance. My insistence on the thrust/wt was to try to see if that would show the reason for the increased performance. As you know hp/wt isn't showing it all. Maybe there was something to be gained in looking beyond that. I don't work with this stuff every day but I do know the plane doesn't magically move thru the air based only on the hp/wt. The prop is pretty important in making things happen.
[This message has been edited by Jimdandy (edited 02-14-2001).]
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Sorry Jimmy I have habit of reading the equations and skipping the roadkill. Comes from grading too many papers I think. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
I just thought it was funny that you would tell Fscott he had oversimplified (ignored variation in prop efficiency) and then threw induced drag out the window. Carry on.
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Originally posted by funked:
Sorry Jimmy I have habit of reading the equations and skipping the roadkill. Comes from grading too many papers I think. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
I just thought it was funny that you would tell Fscott he had oversimplified (ignored variation in prop efficiency) and then threw induced drag out the window. Carry on.
Yes I see where your comeing from. NP.
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PS Jim I didn't know you were an engineer and probably know more about this stuff than I do. There are often some very cheesy interpretations of physics in this forum so I have become quite cynical in my reponses after long-term exposure to this. (http://bbs.hitechcreations.com/smf/Smileys/default/frown.gif)
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Jimdandy, as an engineer u have my respect, but where on earth did u get the idea that a Bearcat had a T2W ratio of approx 1:1? That 1 musta been a RATO assisted model ;-) ..
Whoever said the J2M could not reach the altitude of the B-29 was wrong.To say the addition of cannons wrecked performance & there4 required the installation of a blower is also a little silly.The J2M3 was able to climb to B-29 alt handily.Unfortunately, its top speed at that alt was only slightly greater than the B-29 itself, which is why the J2M5 was built (although in too small a number be4 the war ended), which brought a significant increase in performance thanks 2 a new turbo-supercharger.
Standard J2M3's or M5's did NOT use "Schrage Musik" type upward pointing fuselage cannon.If a small number were so modified, it was not because the J2M could not reach the required alt, but because attacking a Superfortress from below afforded a better element of suprise, and the weight of defensive fire from below was not as great as it would've been from a co- or higher alt. The problem with the J2M3 was not its ability 2 reach B-29 operational alt - its climb rate was excellent 4 a late-war Jap interceptor.Its problem was once up 2 alt, its speed was not sufficient (as I mentioned, this being the reason the J2M5 was introduced).
Btw, although there have been some disparaging statements made about the J2M's handling (including statements attributed 2 Japanese pilots!), a USAAF test-pilot who flew a J2M3 captured in an outlying suburb in the Philippine capital, Manila, described the Raiden as a joy to fly, & the best Japanese fighter he had yet flown (apparently he had flown most of them 2 that time).Its only real vice was that the ailerons became very heavy above 300mph IAS, which was made worse by the fact that the Raiden could pick up considerable speed in a dive & made a change of direction difficult at high speeds.He also complimented the Raiden's excellent rate of climb, which was according 2 him far superior 2 any of the then operational US fighters.
So I guess 2 many Jap IJNAF pilots who'd flown Zekes & Shidens, the Raiden was a bit of a pig as far as handling was concerned.However 2 a US pilot used 2 far less maneuvrable fighters (though superior in performance), the J2M was a joy.
It has 2 be said, however, that IJNAF experten (again, another bloody Teutonic word 2 describe something Japanese ;-D ) used the Raiden 2 its fullest. Aces like Ensign Sadaaki Akamatsu taught the younger IJNAF pilots 2 use Boom'n'Zoom tactics that utilised the J2M's strengths, its high climb rate & excellent dive 2 the max.
In one famous encounter Akamatsu displayed his superior aerobatic abilities (and raw courage, when on April 19, 1945, the 34 yr old Raiden ace flew his J2M against a gaggle of USAAF 45th FS P-51Ds.He forced the Ponies down 2 low-alt & then dispatched 2, with a 3rd claimed as a probable.
[This message has been edited by C_R_Caldwell (edited 02-15-2001).]
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Originally posted by funked:
PS Jim I didn't know you were an engineer and probably know more about this stuff than I do. There are often some very cheesy interpretations of physics in this forum so I have become quite cynical in my reponses after long-term exposure to this. (http://bbs.hitechcreations.com/smf/Smileys/default/frown.gif)
Ya when funked gets too cylindrical..I take a slice off of him to settle him down.
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Originally posted by C_R_Caldwell:
In one famous encounter Akamatsu displayed his superior aerobatic abilities (and raw courage, when on April 19, 1945, the 34 yr old Raiden ace flew his J2M against a gaggle of USAAF 45th FS P-51Ds.He forced the Ponies down 2 low-alt & then dispatched 2, with a 3rd claimed as a probable.
According to Carter and Mueller and Craven and Cates for 4/19/45:
Fighters from Iwo Jima carry out 106 effective strike sorties against Atsugi-Yokosuka area. 24 airplanes are claimed destroyed in the air and 14 on the ground. One P-51 is lost to ground fire and a second fails to return for reasons unknown. 8 P-51's from Iwo Jima bomb and strafe Futamiko. All return to base.
I don't know what P-51s Akamatsu supposedly tangled with, because these were the only P-51s operating independent of high altitude escort duty on that date.
Don't trust Japanese claims.
My regards,
Widewing
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The J2M3 would be nice - maybe a bit slower than the N1K2-J, and with inferior armament, but it would climb at the same rate as the George - with only military power! (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
PS: The J2M5 flew in May 1944 - before the B-29 appeared over Japan in June. Also it had a Mitsubishi MK4U-4 Kasei 26a engine with a mechanical supercharger, rated at 1820hp for takeoff, with military rating of 1510hp at 9185ft, 1400hp at 22,310ft, and 1310hp at 23,925ft. It was the fastest Raiden model, reaching 382mph at 22,300ft. 34 examples were made. This model might be nice as a possible Japanese perk plane. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
The J2M4 actually came after the J2M5 in August 1944, and it was the one with the Mitsubishi MK4R-C Kasei 23c engine with a turbocharger, rated at 1820hp for takeoff, with military rating of 1420hp at 30,185ft. Top speed was 362mph at 30,185ft. It had 4 cannon in the wing, and 2 fuselage mounted oblique-firing cannon behind the cockpit. Only 2 prototypes were completed.
[This message has been edited by juzz (edited 02-15-2001).]
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Originally posted by C_R_Caldwell:
Jimdandy, as an engineer u have my respect, but where on earth did u get the idea that a Bearcat had a T2W ratio of approx 1:1? That 1 musta been a RATO assisted model ;-) ..
Don't ever forget that engineers don't know everything. That has to be one of my BIGGEST pet peeves when someone says "Well your an engineer you should know that." LOL! God there is so much out there to know. I'm a Mechanical Engineer and yes someone in my profession could design propellers, internal combustion engines, irrigation canals, your chair, a nuclear power plant generally structural/civil/mechanical type of things. Even at that those are specialized fields. You can break structural, civil, mechanical, and electrical engineering into at least a dozen specialized fields for each. You learn all the basic design stuff in school and you might take some specific classes that lean toward your hoped for first job. After you get that first job your generally stuck in that field because now that's where you have experience. So you forget half of what you learned because you never use it any more. LOL. So you guys teach me stuff a lot of times. I had read some place in one of the posts the figures for what turns out to be a stripped down record setting F8F. My first love isn't planes it's cars so I don't have a great feel for the data. I just thought it was a bad bellybutton plane and didn't go any farther. Hell I work piping and pipe hangers, thrust, water hammer, friction factors, blah blah etc etc boring crap that pays me money to do what I like. (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif). So please don't wonder how I got the idea as if I should know because I'm an engineer. I never look at prop efficiencies and unless I have the desire to set down and pencil out the problem I'm not going to look that deeply into it. People that love things as a hobby can be just as expert as the experts at times. Hell those old pipe fitters know as much or more a lot of the time about pipe than I do. I guess what I'm saying is engineering is just a job like a pipe fitter, auto mechanics, or hairdresser. Each has the expertise in their field. BTW I was a diesel mechanic before I went to school to be an engineer so I can tell you for a fact just because someone is a mechanical engineer doesn't mean they know about cars. Engineers are the WORST people to have bring in there car. They always think they know more then the mechanic and 90% of the time there wrong LOL!. I know you were just ribbing me but I just hate that! LOL! (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
[This message has been edited by Jimdandy (edited 02-15-2001).]
[This message has been edited by Jimdandy (edited 02-15-2001).]