# Hawker Hurricane Mk.I Propellers



## Zipper730 (Aug 22, 2018)

Did the Hurricanes every operationally use the twin-pitched 3-bladed prop? Or was that for test only?


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## Shortround6 (Aug 22, 2018)

Hurricanes were using the two pitch prop until the summer of 1940. I don't know when the first constant speed props were introduced on the production line but there was a mad scramble with teams of DH propeller specialists traveling from airfield to airfield with truck loads of parts instructing the squadorn fitters how to convert the 2 pitch props to constant speed. The DH crew would make the first conversion with the RAF fitters watching, then they would work together and then the RAF fitters would do a conversion with the DH men watching, if that went well the DH men left enough parts to convert the reaming aircraft and the DH men were back in the truck driving to the next airfield. Hundreds of planes were converted in a short period of time. 
Most, if not all, of the Hurricanes in France had two pitch propellers.


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## Zipper730 (Aug 22, 2018)

Shortround6 said:


> Hurricanes were using the two pitch prop until the summer of 1940.


Okay, here's what I'm looking for...

I don't have any climb-rate figures for the twin-pitch propeller, and while I have figures that list speed, it doesn't seem to cover all altitudes. Here's what I have so far

Climbing Trials: K-5083 (the prototype)
0'...........2550 fpm...151.5 mph...2100 RPM...+6......psi

1000'.....2600 fpm...154.0 mph...2125 RPM...+6......psi
2000'.....2650 fpm...156.0 mph...2125 RPM...+6......psi
3000'.....2710 fpm...158.5 mph...2180 RPM...+6......psi 
5000'.....2810 fpm...163.5 mph...2235 RPM...+6......psi
6500'.....2880 fpm...167.0 mph...2275 RPM...+6......psi
7600'.....2950 fpm...170.0 mph...2300 RPM...+6......psi
10000'...2680 fpm...173.5 mph...2305 RPM...+4.15 psi
13000'...2370 fpm...177.5 mph...2305 RPM...+2.25 psi
15000'...2150 fpm...181.0 mph...2305 RPM...+1.1...psi
16500'...2000 fpm...183.0 mph...2300 RPM...+0.3...psi
18000'...1840 fpm...186.5 mph...2300 RPM...-0.5....psi

20000'...1620 fpm...189.5 mph...2295 RPM...-1.5....psi
23000'...1310 fpm...195.0 mph...2285 RPM...-2.9....psi
26000'.....990 fpm...199.5 mph...2265 RPM...-4.3....psi
28000'.....790 fpm...204.0 mph...2245 RPM...N/A
30000'.....570 fpm...208.0 mph...2210 RPM...N/A

Climbing Trials: L-1547
0’...........N/A......N/A.....+6.25 psi
1000’.....N/A......N/A.....+6.25 psi
2000’.....N/A......N/A.....+6.25 psi
3000’.....N/A......N/A.....+6.25 psi
5000’.....N/A......N/A.....+6.25 psi
6500’.....N/A......N/A.....+6.25 psi
10000’...296......2775...+6.25 psi
13000’...305.5...2850...+6.25 psi 
15000’...312......2900...+6.25 psi
16500’...317......2940...+6.25 psi
17500’...320......2965...+6.25 psi
18000’...319.6...2960...+5.8...psi
20000’...318......2935...+4.0...psi
23000’...312.5...2880...+2.0...psi
26000’...N/A......N/A.....N/A

Everything from 0-6500 feet has nothing except the boost figures which apply all the way up to FTH.


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## Greyman (Aug 22, 2018)

Hurricane squadrons went to France initially with fixed-pitch, 2-blade Watts props. These were upgraded during the Phoney War with two-pitch, 3-blade de Havilland props. They seemed to start getting constant-speed, 3-blade Rotol props in the spring, just before the Germans invaded.

Climb figures for;
Hurricane Mk.I - P5170 - (Cdn built)
Merlin III - de Havilland 2-pitch prop
6,584 pounds

_2,000 feet --- 1800 fpm --- 2190 rpm --- +6.25 boost
10,500 feet --- 2045 fpm --- 2470 rpm --- +6.25 boost
26,000 feet --- _540 fpm --- 2370 rpm --- -4.90 boost

Drawing a line between these three points should get you a reasonable rate of climb graph.

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## Shortround6 (Aug 22, 2018)

Look at the Spitfire trials.


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## Greyman (Aug 23, 2018)

Greyman said:


> Drawing a line between these three points should get you a reasonable rate of climb graph.



Forgot - I already did a quick graph a while back:

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## Zipper730 (Aug 23, 2018)

Shortround6 said:


> Look at the Spitfire trials.


Do the figures compare similarly (i.e. gain in speed per given altitude and RPM)?


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## Shortround6 (Aug 23, 2018)

Think of a propeller like a transmission in a car. 
Fixed pitch prop equals one speed transmission.
2 pitch prop equals 2 speed transmission.

Variable pitch props equal multi speed transmissions but be careful of differences.
A lot of the British props had a 20 degree limit between fine pitch and coarse pitch. 

One test of an early P-40 has a 25 degree difference ( blade angle range 24° to 49° at 42 inch radius) between fine and course and a later test of a P-40E has a 30 degree difference (24.5° to 54.5° at 42" radius). 

Depending on how the fixed pitch or two pitch props were set up they could equal the top speed of the variable pitch propellers. However they limited take-off, climb and acceleration just like trying to drive a single or two speed car. Think of trying to climb in an airplane like trying to climb a steep hill in car, in low gear (if you have a two pitch prop) you may be winding the engine up to max rpm and yet still not moving very fast. In high gear you are lugging the engine, low rpm as you are not moving fast enough to get the engine up to where the power is.
Or the same coming out of a turn, airspeed is 200mph when your max speed in level flight is over 300mph. But your prop is either pushing air sideways and thrashing or you have to reduce throttle (rpm) to let the prop 'grab' the air to get best climb or acceleration. A constant speed prop can suit it's angle of attack to the speed of the aircraft and the speed of the engine. ANd then keep advancing the pitch as the aircraft speed increases, keeping the engine at the desired power level and the prop at an efficient angle of attack to suit the aircraft speed.

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## Zipper730 (Sep 15, 2018)

I'm in the process of creating a pair of graphs which are designed to cover Altitude & RPM and Altitude & Speed. The idea is that I can graph everything from 0-feet to 50000 feet, and TAS from 0 mph to 550 mph. Since some of the graphed speeds seem to list miles per hour to 1/10 mph but altitudes are listed in 50 foot increments so I basically created both graphs 5200 pixels high by either 3700-5700 pixels (RPM 3700, MPH 5700) which allows for 100 pixels on all sides for marking such as altitudes, and also the grids are coded in shades of black/gray to mark off 50', 100', 1000' and 5000' increments. The RPM chart has markings for 10 RPM, 100 RPM, 500 RPM, and 1000 RPM, with the speed chart having 10 pixels for every mile an hour to account for decimals, and markings for 1 mph, 10 mph, 50 mph, and 100 mph up to 550 mph.

The problem with this chart is basically that the basic graph is about 134MB and I figure I could probably reduce the size by converting from XCF (GIMP), PNG, or GIF


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## MIflyer (Sep 15, 2018)

Up to at least 1942 almost all British built multiengined aircraft did not have fully feathering props, including the Whirlwind. The Manchester was about the only exception.

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## Zipper730 (Oct 14, 2018)

This might be slightly off topic, but did the Spitfire use twin-pitch props at any point, or did they go straight to variable-pitch? I do know on WWII Aircraft Performance there were tests done on the twin-pitch propeller...


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## fubar57 (Oct 14, 2018)

Stories of the Battle of Britain 1940 – Constant-Speed Propellers — Battle of Britain | 1940 | Reference | Spitfire Mk. I
https://forum.axishistory.com/viewtopic.php?t=134649
Spitfire Mk.I two bladed propellers
Gooooooooooooooooooooooooooooooooooooooooogle

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## Zipper730 (Oct 27, 2018)

Deleted


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## Zipper730 (Dec 16, 2018)

Deleted


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## Shortround6 (Dec 17, 2018)

wrong thread


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## Zipper730 (Jan 23, 2019)

Here's a downsized version of the graph (24% scale): If I posted this at full scale, I think the forum moderators would lose their mind 

Altitude vs RPM






Altitude vs Speed


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## Zipper730 (Feb 1, 2019)

Greyman said:


> Climb figures for;
> Hurricane Mk.I - P5170 - (Cdn built)
> Merlin III - de Havilland 2-pitch prop
> 6,584 pounds
> ...


And I could simply adjust the lines with what existed for the Hurricane I in the WWII Aircraft Performance page and that should line everything up?

When it comes to indicated airspeed and position & compressibility errors: When they say -1.7 for position error, that means I just take 1.7 mph off the indicated airspeed reading? Does the same apply for compressibility readings?


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## Greyman (Feb 2, 2019)

Zipper730 said:


> And I could simply adjust the lines with what existed for the Hurricane I in the WWII Aircraft Performance page and that should line everything up?



Everything should be in the graph I put in post #6.


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## Zipper730 (Feb 2, 2019)

Greyman said:


> Everything should be in the graph I put in post #6.


The twin-pitch prop seems to have some RPM variances that don't show up in your chart.

I'll put up the data that's from WWII Aircraft Performance and I'll see what can be done


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## Zipper730 (Feb 4, 2019)

Greyman said:


> Forgot - I already did a quick graph a while back:
> 
> View attachment 506730


Where did you derive the data from your chart? Since I have a fairly large graph -- I can do it with more detail and I figure the more detail, it'd be better off.


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## Greyman (Feb 4, 2019)

A&AEE tests. I think almost all of them are on Hurricane Mk I Performance

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## Zipper730 (Feb 4, 2019)

Greyman said:


> A&AEE tests. I think almost all of them are on Hurricane Mk I Performance


I checked the charts, some of the data you have isn't on the list


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## Zipper730 (Feb 15, 2019)

G
 Greyman


So far, from what I graphed, I have the following (I might be off by a bit as I should have measured the slope on the graph), what's in blue is what came right off WWII Aircraft Performance

ALT........TAS
0'...........263
1000'.....266
2000'.....269.5
3000'.....273
5000'.....279.5
6500'.....284.5
10000'...296
13000'...305.5
15000'...312
16500'...317
17500'...320
18000'...319.6
20000'...312.6


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## Zipper730 (Apr 3, 2019)

Here's a mini version of my chart...


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## fubar57 (Apr 4, 2019)

To be readable without a lot of scrolling, the chart should be half as high


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## Zipper730 (Apr 4, 2019)

fubar57 said:


> To be readable without a lot of scrolling, the chart should be half as high


I had miscalculated how small it'd have to be to fit on the screen. That said, I thought of just sending full-sized versions upon request to anybody who asked (just send me a PM with your e-mail address).


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## Wurger (Apr 4, 2019)

The same suggestion I have posted in the Huge Performance Graphs thread.


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## Zipper730 (May 27, 2019)

I'll just compress the files before posting them, that should reduce most problems


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