WWII Rate of Turns

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Okay, so I'll start with the Hawker Hurricane & Supermarine Spitfire and proceed from there...

Hawker Hurricane Prototype K.5083 (In the process of being edited... editing will be made under presumption of 0.477 gear ratio)
  • Speed Trials (Altitude/TAS/Engine RPM/Propeller RPM/Boost/Advance Ratio)
    • 0'...........253.0 MPH...2505 / 1194.9 RPM...20.7.. PSI / 42.15" MAP.....1.6892797329
    • 1000'.....257.5 MPH...2535 / 1209.2 RPM...20.7.. PSI / 42.15" MAP.....1.6989791546
    • 2000'.....261.5 MPH...2560 / 1221.1 RPM...20.7...PSI / 42.15" MAP.....1.708521737
    • 3000'.....265.5 MPH...2590 / 1235.4 RPM...20.7...PSI / 42.15" MAP.....1.7145633732
    • 5000'.....274.0 MPH...2645 / 1261.7 RPM...20.7...PSI / 42.15" MAP.....1.7326612674
    • 6500'.....280.5 MPH...2685 / 1280.7 RPM...20.7...PSI / 42.15" MAP.....1.747339748
    • 10000'...295.5 MPH...2785 / 1328.4 RPM...20.7...PSI / 42.15" MAP.....1.7746841329
    • 13000'...308.0 MPH...2870 / 1369... RPM...20.7...PSI / 42.15" MAP.....1.794971678
    • 15000'...314.0 MPH...2930 / 1397.6 RPM...20.7...PSI / 42.15" MAP.....1.7924655121
    • 16200'...315.0 MPH...2960 / 1411.9 RPM...20.7...PSI / 42.15" MAP*....1.7799492645
    • 16500'...315.0 MPH...2960 / 1411.9 RPM...20.4...PSI / 41.5"...MAP......1.7799492645
    • 18000'...313.5 MPH...2940 / 1402.4 RPM...19.0...PSI / 38.7"...MAP.....1.7835241545
    • 20000'...311.0 MPH...2910 / 1388.1 RPM...17.4...PSI / 35.4"...MAP.....1.7875416952
    • 23000'...306.0 MPH...2860 / 1364.2 RPM...15.25 PSI / 31.05" MAP.....1.7895513884
    • 26000'...298.5 MPH...2795 / 1333.2 RPM...13.3...PSI / 27.1"...MAP.....1.7862872728
    • 28000'...291.5 MPH...2745 / 1309.4 RPM...12.05 PSI / 24.5"...MAP.....1.7761718835
    • 30000'...282.5 MPH...2680 / 1278.4 RPM...10.8...PSI /.21.99" MAP....,1.7630817046
  • Climbing Trials (Altitude/Climb/TAS/Engine RPM/Propeller RPM/Boost/Advance-Ratio)
    • 0'...........2550 fpm...151.5 mph...2100 RPM / 1001.7.,.,.,20.7...psi / 42.15" MAP.....1.2066522270
    • 1000'.....2600 fpm...154.0 mph...2125 RPM / 1013.625..20.7...psi / 42.15" MAP.....1.2121338155
    • 2000'.....2650 fpm...156.0 mph...2125 RPM / 1013.625..20.7...psi / 42.15" MAP.....1.2278758131
    • 3000'.....2710 fpm...158.5 mph...2180 RPM / 1039.86.,,.20.7...psi / 42.15" MAP.....1.2160783413
    • 5000'.....2810 fpm...163.5 mph...2235 RPM / 1066.095..20.7...psi / 42.15" MAP.....1.2235705352
    • 6500'.....2880 fpm...167.0 mph...2275 RPM / 1085.175..20.7...psi / 42.15" MAP.....1.2277893186
    • 7600'.....2950 fpm...170.0 mph...2300 RPM / 1099.485..20.7...psi / 42.15" MAP*....1.2335784456
    • 10000'...2680 fpm...173.5 mph...2305 RPM / 1099.485..18.85 psi / 38.4"...MAP.....1.258975649
    • 13000'...2370 fpm...177.5 mph...2305 RPM / 1099.485..16.95 psi / 34.5"...MAP.....1.2880010241
    • 15000'...2150 fpm...181.0 mph...2305 RPM / 1099.485..15.80 psi / 32.2"...MAP.....1.3133982274
    • 16500'...2000 fpm...183.0 mph...2300 RPM / 1097.1.,.,.,15.00 psi / 30.5"...MAP.....1.3307976778
    • 18000'...1840 fpm...186.5 mph...2300 RPM / 1097.1,.,.,.14.20 psi / 28.9"...MAP.....1.3562500925
    • 20000'...1620 fpm...189.5 mph...2295 RPM / 1094.715..13.20 psi / 26.9"...MAP.....1.3810687712
    • 23000'...1310 fpm...195.0 mph...2285 RPM / 1089.945..11.80 psi / 24.0"...MAP.....1.4273720475
    • 26000'.....990 fpm...199.5 mph...2265 RPM / 1080.405..10.40 psi / 21.2"...MAP.....1.4732059843
    • 28000'.....790 fpm...204.0 mph...2245 RPM / 1070.865..........N/A / N/A...................1.5198565615
    • 30000'.....570 fpm...208.0 mph...2210 RPM / 1054.17............N/A / N/A...................1.5741997604
  • Notes: Diameter estimated at 11.03"
Hawker Hurricane Mk.I will be next
 
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Just to be clear on something, and this might sound stupid: The listed RPM -- is that the propeller's RPM or just the engine and how do you conclude the propeller's RPM if you have the engine RPM?
 
Okay, speed and climb-trials are finished now I'll start setting up data on the Hurricane Mk.I... since I can't find much data on the twin-pitch propellers due to an inadequate supply of data, I'll go right to the constant-speed propeller data.

A/C:...Hurricane Mk.I (L.2026)
Date:..6/12/1940
Weight: 6316 lbs

Climb-Trials

ALT........R/C.....TAS.&&IAS...\\PEC & CEC...CAS.....RPM...Boost & MAP.....Diameter
0'........,,,2500*.............................................................2600.\\+6.25. & 42.65"....10'9"
1000'..,,,2610\\\167......169.5...-4.8 & -0.1............\\...2600.\\+6.25. & 42.65".... "..."
2000'..,,,2615\\\169.5...169.5...-4.8 & -0.1...........\\....2600.\\+6.25. & 42.65".... "..."
3000'..,,,2620\\\172......169.5...-4.8 & -0.1.................2600.\\+6.25. & 42.65".... "..."
5000'..,,,2625\\\177.5...169.5...-4.8 & -0.2.................2600.\\+6.25. & 42.65".... "..."
6500'..,,,2630\\\181.5...169.5...-4.8 & -0.3.................2600.\\+6.25. & 42.65".... "..."
10000',,,2640\\\191.5...169.5...-4.8 & -0.5.................2600.\\+6.25. & 42.65".... "..."
11600',,,2645\\\195......169.5...-4.8 & -0.6.................2600.\\+6.25. & 42.65".... "..."
13000',,,2485\\\197.5...167......-4.6 & -0.7.................2600.\\+5.25. & 40.72".... "..."
15000',,,2250\\\200.5...164......-4.3 & -0.7.................2600.\\+3.9... & 37.97".... "..."
16500',,,2080\\\202.5...161.5...-4.1 & -0.8.................2600.\\+2.95. & 36.14".... "..."
18000',,,1910\\\205......159.5...-3.8 & -0.9.................2600.\\+0.8... & 34.21".... "..."
20000',,,1675\\\209......157......-3.8 & -1.0.................2600.\\+2.0... & 31.97".... "..."
23000',,,1330\\\214......152.5...-3.2 & -1.1.................2600\\\-0.95...& 28.61"... "..."
26000'..,,,990\\\219......148......-2.7 & -1.2.................2600~~-2.55..& 25.45".... "..."
28000'..,,,755\\\223......145......-2.4 & -1.3.................2600\\\-3.6.... & 23.41".... "..."
30000'..,,,530\\\227......142......-2.0 & -1.4.................2600\\\-4.6.... & 21.48".... "..."

Speed Trials

ALT........TAS.&&IAS...\\PEC & CEC...CAS.....RPM...Boost & MAP.....Diameter
0'.......................................................................3000...+6.25. & 42.65"....10'9"
1000'.................................................................3000...+6.25. & 42.65"...."..."
2000'.................................................................3000...+6.25. & 42.65"...."..."
3000'.................................................................3000...+6.25. & 42.65"...."..."
5000'..,,,276......267......-10.0 & -0.8.................3000...+6.25. & 42.65"...."..."
6500'..,,,280.5...265.5...-10.0 & -1.0.................3000...+6.25. & 42.65"..~"..."
10000'...291.5...262......-10.0 & -1.7.................3000...+6.25. & 42.65"..~"..."
13000'...301......258.5...-10.0 & -2.2.................3000...+6.25. & 42.65"..~"..."
15000'...307......256......-10.0 & -2.6.................3000...+6.25. & 42.65"..~"..."
16500'...312......254.5...-10.0 & -2.9.................3000...+6.25. & 42.65"..~"..."
17750'...316......252.5.....-9.9 & -3.2.................3000...+6.25. & 42.65"..~"..."
18000'...316......252........-9.9 & -3.2.................3000...+6.05. & 42.25"..~"..."
20000'...314.5...243........-9.8 & -3.4.................3000...+4.85. & 39.8"....~"..."
23000'...310.5...228........-9.2 & -3.4.................3000...+2.5... & 35.02...~"..."
26000'...305......212.5.....-8.3 & -3.4.................3000...+0.75. & 31.46...~"..."
28000'...299.5...200.5.....-7.4 & -3.3.................3000....-0.35. & 29.22..~"..."
30000'...292.5...188.5.....-6.6 & -3.2.................3000....-1.4... & 27.08..~"..."

The climb-figures for the Hurricane are unfortunately limited to 2600 rpm with +6.25 boost, if anybody knows how to calculate for 3000 rpm, reasonably speaking, I'd love to hear it: I figure I could graph the speeds between 0 & 4000 feet provided it follows some form of non exponential relationship.

Also I'm not sure what to make of the position error calculation and compressibility error calcuation. I figured I could just add or subtract the error and get the correct CAS, but the numbers don't seem to work.
 
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I'm looking at some figures and I'm getting some conflicting data as to gear-ratios and propeller diameter: The Hurricane prototype was stated to have an 11'3" diameter, so I guess I'll rework the numbers; as for the twin-pitch set-up they listed 11.03 feet. It should be what it sounds like 11 feet and 3/100ths of a foot -- is this in anyway an error of 11'3"?
 
swampyankee said:
Prop efficiency is advance ratio times (thrust coefficient divide by power coefficient), so thrust coefficient is equal to (efficiency times power coefficient) divided by advance ratio.
Click to expand...
Okay, so at the penalty of sounding stupid
  1. What does thrust coefficient mean in plain english?
  2. What does power coefficient mean in plain english?
  3. Out of all of this, where does exact thrust figures come out?
Additionally, I could use figures that are based around imperial/english units () since those were heavily used in WWII.

Thanks
 

Thrust coefficient, power coefficient, and advance ratio are non-dimensional coefficients; any consistent set of units could be used. Off the top of my head, I can't give you typical values for these.

Some sources could be:
Slavik, S. "Preliminary Determination of Propeller Aerodynamic Characteristics for Small Aeroplanes", https://ojs.cvut.cz/ojs/index.php/ap/article/viewFile/558/390
and
Hartman, Edwin P and Biermann, David, "The Aerodynamic Characteristics of Four Full-Scale Propellers Having Different Plan Forms", https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091718.pdf








 
Just to be clear, what I'm trying to compute is thrust -- pounds of thrust, newtons, etc, at given speeds. If you want to determine sustained turning performance and climb rates you need to know how much OOOMPF comes out the engines -- with jets it's just "pounds of thrust" or "newtons" depending on what measurement system you're using. I'm trying to get figures like that.
 
With a jet engine the pounds of thrust is not a constant either, it varies depending on all sorts of variables.
 
pbehn said:
With a jet engine the pounds of thrust is not a constant either, it varies depending on all sorts of variables.
Click to expand...
True, but you know what I mean -- I'm trying to determine pounds of thrust.

Advance ratios seem fairly generalized speed versus engine power and RPM. It seems to include exhaust thrust as that's part of the speed. I just need some way to take the advance ratios and turn that into thrust numbers.
 
You have been given them, as with almost every subject you want a simple solution to very complex issues. A jet engine thrust obviously changes with altitude, it changes with temperature, it changes with speed and it changes while manouvering from what I have read as airflow to the inlet changes. So for a jet you need an equation for actual thrust, the quoted thrust for a jet will be in a certain test condition, used to compare to other engines in the same/similar test condition.
 
pbehn said:
You have been given them
Click to expand...
No, I haven't -- at least I don't think I have

This link: Aerodynamic Characteristics of Propellers talks about efficiency, but I don't know what kind of efficiency we're talking about -- what does an efficiency of 0.8 mean? 80% of what?

This link: https://ojs.cvut.cz/ojs/index.php/ap/article/viewFile/558/390 talks about the propeller efficiency provided the blade angles and geometry are known. This is not data I have. I'm just trying to convert he advance ratio into thrust. Is there anyway to do that -- if the answer is no, I can probably still create some large graphs that would provide some use as they're large and highly detailed but would tell me I could avoid bothering trying to compute thrust; if yes -- I'm just trying to find a thrust figure.

T/W helps one determine the angle you could climb at without loss of speed, and would probably also help determine what would happen if the horsepower were increased and decreased. I'm sure that would be useful to somebody.
 
Efficiency is how good something is at doing something. If a gear box and differential is 90% efficient then 90% of the power going in is transmitted to the wheels, the rest is lost. I would say the rest of it requires a lot of knowledge/experience like a degree and cant be imparted in a single post. The blade angle of a CV prop depends on the power load at the time I believe.
 
pbehn said:
Efficiency is how good something is at doing something.
Click to expand...
I'm aware of that, the problem is 80% of what?

The issue isn't an understanding of something like efficiency, I'm just not even sure what the 80% even is for? Thrust to drag? And where do you get the thrust and drag from -- at least if I knew the drag I could probably get the thrust right?
 
Efficiency is defined as useful work out divided by energy in. For a propeller, that would be airspeed (in feet per second) times thrust (in pounds) divided by (horsepower multiplied by 550) or, equivalently, airspeed (in meters per second) times thrust (in newtons) divided by power (in watts).
 
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