Yes and I don't think the differences will be worth the effort or necessarily more accurate. The current assumptions already give good agreement with in flight behaviors.

Propellers design is based on measured data. That is why you cannot work propeller theory accurately without it. That is also the reason why n=.8-.85 is a valid assumption. The design is reworked until it does achieve that level.

That was the biggest lesson of the NACA 16 series and subsequent airfoils derived from calculations. What you think on paper often does not give good agreement at that level due to compressibility.

Propellers spend most of their time in the transonic realm. Even today, the largest potential for error and the most difficult aerodynamic problems are rooted in our ability to mathematically model compressibility effects. Airfoils are designed around coefficients of pressure and our limitations for compressibility modeling hamper our ability to predict behaviors.

With the advent of CFD we are getting better but there are no CFD analysis of WWII era propeller designs.

Drag coefficient is wrong.
In level flight drag = thrust.
D=0.5*density*speed^2*drag_coefficient*reference_a rea
From the above equation calculate drag coefficient and use it to calculate drag at different speeds and altitudes. What you called as "drag coefficient" ans used throughout the different examples is not correct.

Yes, i just simplified the calculation.

For a certain aircraft, wing area is a constant, my compare/data is on the deck, so air density is also a constant(1.29kg/m^3). Therefore, my "drag coefficient"=real "drag coefficient"*constant. The final result will not be different if you use real drag coefficient in the formular.

Of course, but his approximation is not wrong and is based on the relationship of velocity.

There is nothing wrong with doing that as a ballpark of expected behaviors.

I was actually impressed that he did that. It shows an understanding of the relationships indicative of someone with formal education in aerodynamics or at least intelligent enough to work the relationships to conclusion.

Actually they already made the decision in WW1
 

Thanks again for this interesting topic.

I just want to remind that 4-blade propeller fighter aircraft were used before WW2, so perhaps it is not really something as revolutionary as we may think?

Some german design (not produced in great series or prototypes) using 4 blade prop in the 30ies are for instance DO C1 nightfighter (1931) , or Arado 64 experimental (1931).

The oldest fighter design i know using a 4-blade propeller is the german WW1 fighter Siemens Schuckert SSW DIII series (1917-1918 ), that was considered as a very capable fighter at the time, once its cooling problem solved.

The key is airfoil. IMO, at high speed above Vmax:

3-blade Gottingen=3-blade RAF=3-blade ClarkY=3-blade NACA16=4-blade Gottingen/RAF/ClarkY


However, 4-blade NACA16 is an exception. NACA16 was developed after 1939. There are three disadvantages of German propeller edficiency in late WWII AT HIGH SPEED ABOVE Vmax,ie 0.7Mach.

1)smaller diameter with same rpm as allied, so bigger advance ratio, less efficiency(maybe 10-15%). This is confirmed easily.

2) late period wide chord airfoil gives better performance within Vmax, but worse above Vmax(maybe 10%). This is also comformed.

3)allied 4-blade Naca16 outperforms 3-blade naca16 above Vmax. This has NOT been confirmed yet, but probably. maybe 7-10% efficiency improvement.


The third issue is very important, if it is confirmed, allied may have 30% efficiency advantage over German/Russia when above Vmax. If not, or 4-blade naca16 even worse than 3-blade naca16 at high speed. The allied advantage will not be profound.

30% efficiency advantage is around 500-600 HP in late WWII, hugh difference, key role in high speed dive/flight, vital for P47P51 high speed tactics.

Yeah I don't understand the fixation on 4 blades. It is not some magical performance enhancement or brand new technology. For some reason, people like to think that because some of the late war allied fighters went to a 4 bladed propeller that there was something wrong or obselete about a 3 bladed propeller.

You are making a tradeoff between power absorbtion and efficiency. It does not make any difference if you load more power but lose efficiency to convert it to thrust. It also does not make any difference if you increase power absorbtion by adding a fourth blade or widening the chord of the existing three.

WWII really reached the limits of piston engine technology and there is not much to choose or accurately depict in propeller designs. There is a reason n=.85 is valid.

Problem is the NACA 16 series did not realize it's predicted performance. According to the NACA, the Clark Y and Gottingen were equal or better.

Whether 4-blade Naca16 outperforms 3-blade Naca16 above Vmax is NOT confirmed, the confirmed fact is that 3-blade naca16=3-blade ClarkY and 4-blade ClarkY=3-blade ClarkY.

Even assume 4-blade naca16 has no advantage above Vmax at all, that is to say, P47P51 is equipped with German old narrow chord Gottingen airfoil, P47 still has around 20% efficiency advantage(300-400HP) above Vmax, ie 0.7Mach.

So simply assuming 85% for all CSP when above Vmax is totally unacceptable for high speed tactic il2 players.

Not anything outstanding about the propeller and everything to do with the engine.....


This condition is key. Of course, above Vmax we are outside of the aircrafts design envelope and our efficiency curve no longer approximates a slope of zero. Instead it takes on a negative slope.

Just though as it is a good assumption to have a slope of zero in the envelope, it is also a good assumption that all CSP designs will have a similar negative slope outside that envelope.

See:


Now, that is not to say it would not be very cool to add the minor differences outside the envelope and some very basic assumptions could be made based on general propeller characteristics. A generic curve could be the thing that fixes the "supersonic dives" that are possible in the game.

I also think that individual and specific characteristic's are way more trouble than it is worth for dubious accuracy without the actual data. It would also open up a huge can of worms for your developers and people having to decide what data is applicable.

Look at all the arguments over such very well documented performance parameters as climb rates or Vmax. Now you want to add in propeller design?

The whining would never stop, not that it does now.

My suggestion would be to concentrate on accurately modeling the limits and behaviors found in the Operating Instructions.

I think it would be more realistic and easier to model the consequences of exceeding the dynamic pressure and mach limits of the aircraft than trying to find a generic braking point. You don't think, "my efficiency curve will drop off and drag rise due to compressibility will keep me safe" when you point an aircrafts nose down in a steep dive. You think, "don't exceed Vne...don't exceed Vne" as your butt cheeks suck up the seat.

For example, our FW190 tries to dive away from a P47. At ~466mphTAS, the FW encounters compressibility, and loses elevator control. The FW now happily sails to the dirt barrier or the pilot very very carefully uses the elevator trim to recover without overloading the airframe.

At 466 mph TAS, the P47 is in full control. He either:

1. Watches the FW hit the dirt barrier from the comfort of altitude.

2. Catches the FW on its straight path to the dirt barrier and shoots it down. His top speed is ~40 mph faster...

2. Follows the FW on its rather helpless recovery and shoots it down.


Diving away is a very bad option for the FW190 if the limits are accurately modeled.

The most important factor of a propeller is its size/diameter. if you fly your P47 with a 3.3m diameter prop instead of a standard 4m, you'll definitely lose more efficiency, perhaps 10%, at 0.7Mach(above Vmax).

efficiency is Y axis, advance ratio is X axis, although 3.3m prop share same slope curve as 4m prop outside the envelope, the 3-meters prop working point is on the right side of 4-meter due to higher advance ratio, which means less efficiency.

Yes, this efficiency curve is a Pandora box. If il2 FM gets improved in propeller efficiency curve, the drag coefficient of many aircraft should be different from ealier, otherwise, how could aircrafts get accurate Vmax as historical data? For many years, blue side fans and red side fans argued a lot about engine output, boost level such as 1.8ata, 21lbs ,25lbs boost etc..... Now what ? Taking away 500HP from my engine when high speed dive? To degrade my bf109G6as into a bf109G6? OMG, just kill me.

When dive to 800km/h, the real world air compressibility costs more 200HP power than il2's none compressibility FM. It's not news and is already known by many people. Forthermore, as you said, in il2 4.11m, fw190 still has good elevator control above 466mph=750km/h.

However, my interest is not above 750km/h, just between Vmax(680km/h) and 750km/h. Could P47 get more efficiency than fw190 when steeply dives to 750km/h and then maintains 740km/h for 30 seconds in a shallow 10 degree dive?

It is a good tactic for fw190 to dive away from spitfire. As <<Tempest in War>>said, many fw190 tried dive away when pursued by Tempestmkv, of course those fw190 usually got shot down. In history, those fw190 pilots succeeded in outdiving spitfire before they met tempest. That's why they tried dive away from tempest, they thought spitfire and tempest are similar in dive, but they were wrong.

Again, dive limit is NOT dive acceleration, IF my fw190 could dive faster than your P47 WITHIN 750km/h=466mph, I'll try dive away from P47 because that's a good idea. I'll keep dive speed within 466mph, so that your P47 has no chance to show higher dive limit. I'm sure I can get far away from your P47.

But the truth is that within 466mph, P47 still dives faster.

Not sure what you are trying to say here...

You do understand you cannot compare propellers at different advance ratio's???
It is not in any way or form valid.

I think this where you are getting confused.

Advance ratio is analogous to angle of attack.

If you looked at angle of attack in isolation as a measure of turn performance for example, you would erroneously conclude that the aircraft at the higher angle of attack can outturn one at a lower angle of attack.

This is patently false and has no bearing on turn performance.

You can only make a valid comparison of propellers at the same advance ratio. The fact other propellers can achieve higher advance ratio's has no bearing on their performance when compared to lower advance ratio propellers anymore so that wing angle of attack can be used for turn performance prediction.

Not at top speed or dive performance.

In general....Smaller disc = higher top speed because a large disc means more tip lose.

Larger disc means better low speed performance, ie take off, climb, cruise, and turn.

Examine the diameter of supersonic propellers.....

I can't compare 2 propeller efficiency by using a single propeller curve.

But fw190 advance ratio from 2.54 to 3 when TAS 680km/h to 800km/h. 0.46 is difference.

P47 advance ratio from 2.1 to 2.47 when TAS 680km/h to 800km/h. 0.37 is difference.

if both share same efficiency drop slope above vmax, fw190 lose 5% more than p47. btw, German wide chord prop lose 8% efficiency compared to old narrow design because of 4% Vmax lose.

so if p47 equipped with 4 meter German old narrow prop, p47 should get at least 13% efficiency advantage over fw190a8 new wide chord propeller at 800km/h. furthermore, German wide chord dosen't share same efficiency slope as narrow prop above Vmax because within Vmax wide chord is better and at Vmax wide chord is worse. so wide chord has a steeper drop slope than old narrow chord design.

that is to Say, p47 with old narrow German airfoil 4meter prop could get almost 20% efficiency advantage at 800km/h TAS which is smaller than 466mph IAS.
Attachment 10059
what allied propeller engineers did in WWII is just maintain German WWI standard airfoil performance? of course not.

story becomes complicated when allied developed naca16 and paddle wide chord propeller.

1944 early, both German and allied began to use wide chord airfoil in fighters:fw190a8 and p47d-25

with wide chord design,German get better climbe and turn performance, so was allied.

http://www.368thfightergroup.com/P-47-R2800.html

p47 got more than 10% climbe rate due to wide chord paddle propeller.

It is noticed that p47 propeller is so big that tip Mach too high, above 1 Mach, if you reduce rpm from 2700 to 2520(bigger advance ratio),you'll get 6% more efficiency at 800km/h. But that dosen't mean fw190 could get higher efficiency due to higher advance ratio than p47. fw190a8 prop tip Mach is usually less than 1 mach(1 Mach @800km/h). A bit complicated.
http://digital.library.unt.edu/ark:/...dc62616/m1/25/

Question:

1) Do allied wide chord paddle props suffer efficiency lose just like German wide chord cousin at 750-800km/h?

we don't know.

1) 3-blade naca16 is same as 3- blade clarkY at 750-800km/h. So is the 4-blade vs 4-blade compare?

we don't know.

But one fact is very clear: prop efficiency may lead to hundreds of horsepower difference above Vmax, so a simulation game must pay enough attention to detailed efficiency curve. otherwise, a big difference from history is inevitable.

those supersonic propellers max tip Mach is more than 1.3 while WWII p47 max tip Mach is below 1.15. quite different story.

Come on man....

You understand the basic's of rotational mechanic's right?

On any radius of the circle, the point closest to the origin travels at a slower velocity than a point distal to the origin.

That is why as a generality, a smaller disc is better for Vmax performance.

I am not exactly sure what you are looking at.

CSP's are not compariable at different advance ratio.

Attachment 10062
There are two shock wave areas in propeller.

One is near tip, the other is around root.

Ma----compound speed, =squareroot of (rotating speed^2+ TAS^2), Mach

Mak----critical shock wave stall speed for a certian airfoil, Mach

The propeller portion near root is usually thick and not very streamline, so Mak is quite low which means easily render shock wave. The tip portion, on the other hand, has a very high(near sonic)Ma, so shock wave inevitable although this portion is quite thin and streamline.

Afterall, there is a trade off upon propeller's diameter above Vmax, if you use a bigger one, the shock wave area near tip is quite big, bad thing. But you get a smaller advance ratio, that's a good thing.The art is to find a optimum point where whole propeller reaches maximum efficiency at a certain speed above Vmax.

Speed is an important concept in combat, just like altitude. Pilots know what's the best altitude for their aircraft, eg, P47D, are willing to fight fw190/bf109 above 6000m altitude. If fly a La7, the lower altitude, the better. Why altitude is so important? one reason is "engine output".So is speed.

If your opponent will lose 500HP at a certian speed between Vmax amd Vne due to lower propeller efficiency, you also wanna drag him to such high speed and beat him in an energy fight style.


The samller aircarft, the lower drag coefficent and smaller weight, thus easier reach high speed and better output/weight ratio. One couldn't have it both ways.Shouldn't those tiny soviet/German aircrafts pay the price during high speed dive? :)

Right, as a function of angle of attack and not diameter....

You are getting into the weeds without keeping an eye on the big picture. Propeller designers are aware of of this and design accordingly. It is too easy to spot a bad propeller design very early on.

It is a general principle that smaller diameter is better for Vmax performance.

Keep the discussion to diameter effects.....

Take a lesson from Professor Von KlipTip.....:grin:

http://www.google.com/url?sa=t&rct=j...KCOmcUBIgbeK8Q

All of this comes out in standard performance calculations. In this case, subsonic incompressible flow theory works very well at predicting subsonic propeller design behaviors.

For example, you don't have to add anything when crunching the numbers for a FW-190 regardless of the propeller.

If you plug in the data for a metal propeller, your drag is less which means less lift and your sustainable turn performance envelope is reduced.

If you plug the data for a wide chord wooden propeller, your drag increases resulting in more lift and your sustainable turn performance envelope increases!

It is all in the math!

What is the basis you will manipulate the curve? Propeller design is extremely complex and once again, it is too easy to spot a bad design very early on. Like first flight early, LOL.

This appears to be a license to manipulate aircraft behaviors based on intuiation and supposition.

Propeller design is just too complicated and easy to spot a bad design. There is a reason why a generic curve is acceptable!

This is NACA16 airfoil 3-blade vs 4-blade efficiency compare at 0.4 Mach.

Obviously, 4-blade NACA16 outperforms 3-blade NACA16 WITHIN Vmax. There is 8% difference. What's the meaning of 8% efficieny for a 2000HP engine? 160HP!

What's the 18lbs spitfireXIV and 21lbs spitfire XIV Griffon 65 engine difference? （2220HP-2050）*85%=145HP!
What RAF did in order to achieve 21 lbs boost with spitfire XiV? Gear midification, 150 octane fuel, and so on.

Attachment 10100

But there is only 2% difference between 3-blade and 4-blade RAF6/ClarkY.
Attachment 10101
Attachment 10102
Attachment 10103

So NACA16 shows its outstanding/distinct character WITHIN envelope/Vmax.

RAF6, ClarkY and Gottingen airfoils are all conventional and of WWI peroid when biplanes dominated the sky. NACA16 was developed after 1939, new airfoil. And NACA16's advantage is NOT directly outperforms conventional airfoil in 3 blade configuration, its benefit only available when you add the fourth blade. There are two benifit:

1)Within Vmax. With the 4th blade, naca16 get 8% more efficiency while RAF6/ClarkY/Gotingen get 0% even negative.

2)above Vmax, with the 4th blade, naca16 could maintain stable efficiency（drops slightly） when advance ratio reaches 3.0. Those conventional airfoils usually in 3-blade configuration, and a 3-blade propeller efficiency drops sharply when advance ratio=3.

What are those picture telling us?

4-blade hamilton Standard 3155-6 outperforms 3-blade 6507A-2 above envelope.



OK, let's compare efficiency at SAME advance ratio. 4-blade Hamilton Standard 3155-6 could maintain 82% efficiency (in free stream)when advance ratio=3, that's a splendid achievement. How about 3-blade Hamilton Standard 6507A-2 at 3 advance ratio(J)?

V=J*(n*d)=3*23*4=276m/s=994km/h=0.81Mach

From the picture I posted, we can estimate 3-blade Hamilton get around 40% at 0.81 Mach.

We know fw190 dive limit is 466mph=750km/h IAS=900km/h at 3000 m altitude. Let's exam 3-blade vs 4-blade configuration at 800km/h TAS, only 666km/h IAS @3000m altitude, it's very safe for a fw190, quite smaller than Vne, isn't it?

800km/h = 0.66 Mach

For 4-blade Hamilton Standard 3155-6, no worries, efficiency around 85%, well done.
For 3-blade Hamilton Standard 6507-A2, 70-72%, not bad.
For fw190 3.3m diameter 3-blade propeller, advance ratio=2.78, let's assume it performance just like Hamilton Standard 6507-A2 at 2.78 advance ratio(0.75 Mach), we get 52% efficiency!

There are 30% efficiency difference between allied 4-blade propeller and German/soviet 3-blade, 30%, wow, that's 500-600HP engine output bleeding, serious problem if allied aircrafts drag them to 666km/h IAS=800km/h TAS@3000 m/10000ft altitude. We know even La7 could withstand 666km/h IAS, isn't it?

Don't forget German wide chord airfoil even worse than narrow old airfoil at Vmax.


Crummp, I think I've expressed my opinion clearly with my proof/data, my suggestion is to take away 500-600HP from German/soviet aircrafts above Vmax and within Vne. If you could provide the evidence that 3-blade propeller achieve 80% efficiency at 2.8 advance ratio, you'll win. Now it's your turn.

You need to learn to read those plots. The 4 bladed propeller cannot reach an advanced ratio of 2.78 for much of the Cp range.

The blades stall and it produces no thrust!!!

Read the report!!!

Is not correct.

Let's looks at the report. The first thing that stands out as a glaring anomaly in the chart you posted is the fact a 4 bladed propellers appears to be more efficient than a 3 bladed propeller.

This violates a basic principle, sort of like all those people who want to claim their higher wing loaded aircraft can outturn a lower wing loaded airplane. Sounds nice but is not going to happen.

That principle is the fewer blades, the higher the efficiency.

The NACA is not claiming a 4 bladed propeller is more efficient. In fact, they quite notably point out several times in the report that none of the data is corrected for wind tunnel installation.

In English, it is not good for specific comparison and they plainly state that in the conclusions. They just hung the propellers and went with it to get an idea of the general trends.

The NACA conclusion are the ONLY thing that can drawn from this report.

You calculated for an advance ratio of 2.78. The 4 bladed propeller produces NO THRUST for most of the power loading conditions at J = 2.78.

When the polar line ends, the blade is stalled!!!

Your theory is not based on facts. It would be a fundamental error to toss aside convention of n = ~.85 for it.

http://img37.imageshack.us/img37/803...4bladeresu.png

This is not the same airfoil....

Will a 4-blade propeller outperforms 3-blade one?

It depends on many factors such as diameter, airfoil, revolution, chord width, blade thickness, TAS, an so on. You know propeller is very complicated.

But for Hamilton standard 6507A-2(~4meters, Naca16 airfoil), 4-blade configuration is better than 3-blade, this is a fact you should accept.

In fact, in late WWII, Rotel, the name is a contraction of "ROlls-Royce" and "BrisTOL", had introduced the first five-bladed propeller to see widespread use

http://upload.wikimedia.org/wikipedi..._with_crew.jpg

http://en.wikipedia.org/wiki/Rotol

21lbs boost Griffon 65 engine of spitfireXIV is around 2200HP, with a five-blade , wood propeller.

The fastest Mustang----XP51G, with a 2200HP engine, with rotel five blade wood propeller.

The XP-51G was a development aircraft that combined the light weight airframe developed for the XP-51F with an experimental Rolls Royce RM-14SM engine, capable of producing 2,000hp at 20,000 feet. The new aircraft achieved a top speed of 495 mph, and a climb rate of 5,000 feet per minute, well over 1,000 feet per minute faster than the P-51D. However, the new Rolls Royce engine was too complex and did not always produce its best power.

1945 early, the 13lbs boost TempestMKV, 2700HP sabreiib engine, with rotel five blade wood propeller.

After WWII, people developed 6 and even 8 blade propeller.


Attachment 10146
Attachment 10147

3-blade vs 4-blade compare when developing YP47M. Do you mean these are just to get an idea of general trends?


1350 rpm=23rps, 4 meter Hamilton standard 6507A-2, when advance ratio is 2.78, the TAS=2.78*23*4=256m/s=920km/h=571mph.

When P47 dive to such speed, no propeller thrust? How does il2 FM calculate propeller in this situation? Still 85% efficiency?

The test air speed is below 0.4Mach or 0.2 mach . Of course, 0.4 Mach is just a cruise speed, at medium-low speed, 3-blade CSP could get constant propeller efficiency within envelop.

4-blade propeller efficiency drops from 90% to 85% while 3-blade remaining constant 81%.....


If you test propeller with slow air speed and small propeller rpm, a 4-blade propeller could maintain constant efficiency up to 3.6 advance ratio.

It is the high Mach number decrease propeller efficiency. No air compressibility, no significant effociency drop.

Btw, in late WWII, almost 100% allied aircrafts equipped with 4-blade propeller.

Note that ClarkY 4,6 blade test was carried in a low speed wind tunnel, only 110mph, only 550rpm. So there is no air compressibility in the test, 4-blade propeller could maintain 80% efficiency up to 3.6 advance ratio.


I have no direct proof of 4-blade NACA16 efficiency at high Mach number. I just suspect that 3-blade 3.3m propeller lose efficiency much more than a 4-blade Naca16 around 0.65-0.75 Mach----above level speed envelope, within dive limit.

XP-51G max level speed=495 mph, P-51D=442 mph.

If everything being equal, XP-51G need (495/442)^2= 125% engine thrust of P51D. Obviously, 2200HP Rolls Royce RM-14SM is around 125% output of 3000 RPM and 67" stanard Merlin(1760HP at altitude).

Roughly, we can say Britain Rotel 5-balde wood propeller is as effective as those 3-4 blade CSP at speed envelop. Namely, around 80% efficiency at 495mph=800km/h TAS.

It seems that allied believed in wwii that 4 or 5 blade propellers are better than 3-blade when speed is high(>700km/h?).

Yes

Power absorbtion is what they were going for....

3000 hp engines where the next step on the horizon.

Large amounts of effort for little gain in a 3000 hp piston engine aircraft.

Jets eclipsed any further piston engined development.

I think you answered this one yourself.

1945 version Dora, 2200HP. 3-blade propeller.

1944 late Spitfire XIV, 2200 HP, 5-blade propeller.
http://www.spitfire.dk/Grafik/5blade_prop.jpg
1945 version Spitfire XIV,2200HP, 6-blade(2X3-blade contra rotating ) prop. To remove massive torque.
http://www.spitfire.dk/Grafik/MkXIX_Contra1.jpg
http://www.spitfire.dk/Grafik/MKXIX_Contra2.jpg

3-bladed hollow Aeroproducts prop in 1944 for max speed of 491 mph
 

It is interesting to note that there was also attempts to switch back to 3 bladed-prop during the developpement of the famous P51.

The lightweight XP-51F, just as XP-51G, is a completely new design, NOT a modified P51D: can we just compare them to the D series?

The XP-51F apparently used a 3-bladed hollow Aeroproducts prop in 1944 for max speed of 491 mph.

Would be interesting to know more about this propeller too.

6 blades!!!

No, that is TWO 3-bladed propellers turning in opposite directions from each other.

:)

* * * *
*
Some resource pointed out that xp-51f is 20-30mph slower than xp-51g. Only 466mph=750km/h TAS.
btw,750km/h TAS is not a very high dive speed.


Engineering inspections were held in February 1944. The first XP-51F was flown by Bob Chilton on February 14, 1944. The second and third XP-51F flew on May 20 and 22 of that year. Equipped empty weight was about 2000 pounds less than that of the P-51D, and combat weight was 1600 pounds less. The engine was the Packard Merlin V-1650-7 engine of 1695 hp, same as the powerplant of the P-51D. Considering that the equipped empty weight was about a ton less than that of the P-51D, the performance improvement was not as spectacular as might have been anticipated-- maximum speed was 466 mph at 29,000 feet.


The second XP-51G was shipped to the United Kingdom in February 1945. This plane was also named Mustang V, and bore the RAF serial number FR410. It is widely reported to have achieved a speed of 495 mph during tests at the A&AEE at Boscombe Down in February 1945, although NAA claimed only 472 mph for the other G at the same altitude. However, by this time RAF priorities had changed, and no further flight testing took place. The fate of FR410 after the end of test flying is uncertain.