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XyZspineZyX
09-04-2003, 07:01 AM
Salute All

I have been continuing my testing of the Brewster.

I originally did a series of tests based on the original Brewster company documents available here:

http://www.hut.fi/~ssipila/brewster/brewster-350.pdf

Page #4 of that document shown below:

http://members.cox.net/rowlandparks/b239.jpg


This lists a test at normal power for climbrate for an aircraft equipped with only a single .50 calibre gun and a single .30. This plane was loaded with only 110 gallons of fuel and weighed 5014 lbs or 2279 kgs.

Climbrates according to the document are estimated to be

2 minutes to 5,000 ft

6 minutes to 15,000 ft

That translates to a climbrate of 2500 ft per minute.

I did a series of tests at normal power which far exceeded the climbrate listed on the documents.

However, I was told by Jippo and other Finnish Flyers that the Brewster company documents are incorrect and do not relate to the Model 239 as received by the Finns. This despite the fact the above manual was supplied in the packing cases in which the Brewsters arrived in and are labeled for a Model 239 Brewster, and the Model 239 was not supplied or used by any other country but Finland...

Jippo provided another document which he specified showed the correct climbrate shown below:

http://www.kolumbus.fi/jan.niukkanen/BW.jpg


This chart shows a climbrate in either Meters per second, or climb times to altitude in meters.

He said this test was done with the aircraft fully fueled with 160 gallons, and equipped with four .50 calibre MG's. (and I quote Jippo)

"The plane is the BW-366. The take-off weight is not known in this case, but the Finnish tests I have read about different planes are usually flown with full fuel load and ammunition in standard (not specially prepared) plane. Typical take-off weight of thus loaded BW was 2415kg, (5313 lbs) and the plane in the test "..must have been between 2300-2400kg."

Manifold pressure was 93cmHg and rpm 2100, which is the 850hp setting at sealevel. I would like to remind that the maximum power was 1000hp, so there is still quite a difference to that. climbing speed in this test was 220kmh IAS at SL reducing to 180kmh at 5000m."

As mentioned above, Jippo says that the test was done at normal power rating, not WEP.

Although I have my doubts about this Finnish test being done with full fuel load and at normal power, I decided to do the tests again according to his criteria.

I used 100% power, full fuel load, full ammunition.

I started the test from Sea Level, right on the wavetops, at 300 kph according to the methodology used by Beta Testers according to Ian Boys.

I used a climb speed of 180 kph, and switched over to stage 2 of the supercharger at 9,000 ft. I did not change the fuel mixture from 100% and used that for the entire test.

I did the test 3 times and averaged the results.

The following were the times I got:

In Meters:

1,000 meters :58

2,000 meters 2:06

3,000 meters 3:23

4,000 meters 4:35


Jippo's chart shows the following times to altitude: (and its difficult to read being small so these are approximations)


1,000 meters 1:20

2,000 meters 2:30

3,000 meters 4:00

4,000 meters 5:30


If we look at the Meters per second rate on Jippo's chart, which is a little easier to read, we can see that between ground level and 2000 meters, the aircraft averages a climbrate of between 12.8 and 13.2 meters per second for an average of 13 meters per second.

Using the time to 2,000 meters from my tests, we get a figure of 15.87 meters per second.

Translating both of those figures into feet per minute we get a climbrate from Jippo's chart of 2559 ft per minute from sea level.

My tests show a climbrate of 3124 ft per minute from sea level.

Conclusions are obvious. Even if we accept that Jippo's chart is correct and that the Finnish test Brewster, loaded to 5313 lbs could climb better than the plane listed in the Brewster company documents which weighed 5014 lbs, we still can see that the FORGOTTEN BATTLES Brewster considerably exceeds even Jippo's chart for climbrate.

It is clearly overmodelled for climbrate.

I would also like to remind people that Oleg's Object viewer chart has a climb time for the Brewster to 3,000 meters of 4:12. Since Oleg normally uses WEP when calculating climbs, the figure of 3:23 for the current model of the Brewster, calculated at normal power, is far in excess of his listing.


RAF74 Buzzsaw

P.S. Anyone who would like a copy of my test records of the climbs, send me a PM and your e-mail and I will send them.

XyZspineZyX
09-04-2003, 07:01 AM
Salute All

I have been continuing my testing of the Brewster.

I originally did a series of tests based on the original Brewster company documents available here:

http://www.hut.fi/~ssipila/brewster/brewster-350.pdf

Page #4 of that document shown below:

http://members.cox.net/rowlandparks/b239.jpg


This lists a test at normal power for climbrate for an aircraft equipped with only a single .50 calibre gun and a single .30. This plane was loaded with only 110 gallons of fuel and weighed 5014 lbs or 2279 kgs.

Climbrates according to the document are estimated to be

2 minutes to 5,000 ft

6 minutes to 15,000 ft

That translates to a climbrate of 2500 ft per minute.

I did a series of tests at normal power which far exceeded the climbrate listed on the documents.

However, I was told by Jippo and other Finnish Flyers that the Brewster company documents are incorrect and do not relate to the Model 239 as received by the Finns. This despite the fact the above manual was supplied in the packing cases in which the Brewsters arrived in and are labeled for a Model 239 Brewster, and the Model 239 was not supplied or used by any other country but Finland...

Jippo provided another document which he specified showed the correct climbrate shown below:

http://www.kolumbus.fi/jan.niukkanen/BW.jpg


This chart shows a climbrate in either Meters per second, or climb times to altitude in meters.

He said this test was done with the aircraft fully fueled with 160 gallons, and equipped with four .50 calibre MG's. (and I quote Jippo)

"The plane is the BW-366. The take-off weight is not known in this case, but the Finnish tests I have read about different planes are usually flown with full fuel load and ammunition in standard (not specially prepared) plane. Typical take-off weight of thus loaded BW was 2415kg, (5313 lbs) and the plane in the test "..must have been between 2300-2400kg."

Manifold pressure was 93cmHg and rpm 2100, which is the 850hp setting at sealevel. I would like to remind that the maximum power was 1000hp, so there is still quite a difference to that. climbing speed in this test was 220kmh IAS at SL reducing to 180kmh at 5000m."

As mentioned above, Jippo says that the test was done at normal power rating, not WEP.

Although I have my doubts about this Finnish test being done with full fuel load and at normal power, I decided to do the tests again according to his criteria.

I used 100% power, full fuel load, full ammunition.

I started the test from Sea Level, right on the wavetops, at 300 kph according to the methodology used by Beta Testers according to Ian Boys.

I used a climb speed of 180 kph, and switched over to stage 2 of the supercharger at 9,000 ft. I did not change the fuel mixture from 100% and used that for the entire test.

I did the test 3 times and averaged the results.

The following were the times I got:

In Meters:

1,000 meters :58

2,000 meters 2:06

3,000 meters 3:23

4,000 meters 4:35


Jippo's chart shows the following times to altitude: (and its difficult to read being small so these are approximations)


1,000 meters 1:20

2,000 meters 2:30

3,000 meters 4:00

4,000 meters 5:30


If we look at the Meters per second rate on Jippo's chart, which is a little easier to read, we can see that between ground level and 2000 meters, the aircraft averages a climbrate of between 12.8 and 13.2 meters per second for an average of 13 meters per second.

Using the time to 2,000 meters from my tests, we get a figure of 15.87 meters per second.

Translating both of those figures into feet per minute we get a climbrate from Jippo's chart of 2559 ft per minute from sea level.

My tests show a climbrate of 3124 ft per minute from sea level.

Conclusions are obvious. Even if we accept that Jippo's chart is correct and that the Finnish test Brewster, loaded to 5313 lbs could climb better than the plane listed in the Brewster company documents which weighed 5014 lbs, we still can see that the FORGOTTEN BATTLES Brewster considerably exceeds even Jippo's chart for climbrate.

It is clearly overmodelled for climbrate.

I would also like to remind people that Oleg's Object viewer chart has a climb time for the Brewster to 3,000 meters of 4:12. Since Oleg normally uses WEP when calculating climbs, the figure of 3:23 for the current model of the Brewster, calculated at normal power, is far in excess of his listing.


RAF74 Buzzsaw

P.S. Anyone who would like a copy of my test records of the climbs, send me a PM and your e-mail and I will send them.

XyZspineZyX
09-04-2003, 07:14 AM
Salute

As test pilot for the Royal Navy, Eric Brown flew scores of aircraft from many nations. He wrote short essays on 36 of them for Wings of the Weird and Wonderful, published by Airlife in Britain and Tab Books in the U.S.

Capt. Brown flew a Belgian-order Brewster 339 at Royal Naval Air Station, Yeovilton, early in 1941, along with a Grumman Martlet, as the British called the F4F Wildcat.

"They were both tubby little single-seat fighters with a very purposeful air about them..."

Brown noted that there were 40 of these Model 339b planes, acquired when Belgium fell to the Germans, and shipped to Britain aboard HMS Furious. They were assembled at Burtonwood, later a huge American base--near Manchester. He obviously had his notes in front of him as he wrote the Buffalo chapter:

"Once in the cockpit I found the view ahead rather poor because of the aft position of the pilot and the high position of the nose. In spite of this, the aircraft was very easy to taxi, as the brakes were smooth and very efficient.
On take-off the throttle had to be opened carefully as there was no automatic boost control, and the stick [had to be] moved forward to get the tail up and improve acceleration. The rudder control was very good in keeping the aircraft straight on its short run.
The climb was steep and initially at a rate of 2,000 ft./min. but soon began to fall off noticeably as altitude increased. The longitudinal stability was decidedly shaky and would make instrument flying very difficult. [Commenting on another a/c, Brown noted that longitudinal instability was a good feature in a fighter.] It was also apparent that there were [exhaust] fumes coming into the cockpit....
In normal cruise at 160 mph the aircraft was longitudinally unstable, laterally neutral stable, and directionally positively stable. Maximum speed was 290 mph at 16,500 ft. and the service ceiling was only 25,000 ft. Not very impressive performance. However, it was a different story when it came to handling, for the ailerons were highly effective throughout the speed range, the elevators almost equally so, and the rudder very good too.
The all-up stall occurred at 76 mph with a sudden but mild wing drop followed by the nose. The all-down stall was at 67 mph with similar but slightly more pronounced characteristics.
For landing the undercarriage was lowered at 95 mph followed by the slow moving flaps at 90 mph. An approach speed of 80 mph gave a reasonable view, but needed almost full backward elevator trim. Touch down occurred at 75 mph with a good pull back on the stick to achieve a three-pointer as the power was cut. Once on the ground the aircraft could be kept nicely straight on rudder with a discreet touch of brake.
My feeling after flying the Buffalo was one of elation tinged with disappointment. It was a true anomaly of an aeroplane with delightful manoeuvrability but poor fighter performance. Indeed above 10,000 ft. it was labouring badly."

A few comments about the Belgian model 339B:

This aircraft was not as bad as the British and USN models, falling between them and the Finnish model for weight.

It had an empty weight of 4019 lbs, compared to the Finnish empty weight of 3744 lbs.

It had a higher horsepower engine than the Finnish model, rated at 1100 hp for WEP and 900 hp for normal operation. This compares to 1000 and 850 for the Finnish Model 239.


RAF74 Buzzsaw

XyZspineZyX
09-04-2003, 07:54 AM
Crusade against BWhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

BW is easy to avoid if you want to. It is so slowhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

XyZspineZyX
09-04-2003, 07:56 AM
Salute

More testing of 339b's:


"Take-off - The take-off is very smooth and straightfoward, with no tendency to bounce or bucket. After opening the throttle the throttle the tail remains down for about 30 yards, but holding the stick right forward brings the tail up very smoothly. The elevator control is not too sensitive as on the Spitfire or too sloppy as on the Hurricane. As the speed increases the aeroplane has a slight tendency to swing, which, however, is very easy to control. . . . The aeroplane flies off without assistance after a take-off run which is short than that of either the Spitfire or Hurricane; when airborne it increases speed quite rapidly and has a good initial rate of climb.
Landing - The approach glide at 90-95 m.p.h. is steep, making the landing easy and giving an excellent view of the aerodrome. Because of the slight sinking impression the pilot tends to flatten out slightly higher than usual, but the aeroplane settles down after a small float with no bounce, bucket, or swing. The brakes can be used after touching down, they operate smoothly and effectively and the ground run is not very long.
Taxying - On the ground the aeroplane is very maneuverable--it can easily be turned in its own space with the aid of a little braking, which is most effective and quite smooth, the tail wheel is not steerable. The view is good except directly ahead where it is obscured by the high position of the nose.
Ailerons - Tests in the speed range from the approach glide to 400 m.p.h. showed the ailerons to be exceptionally effective; they are crisp and powerful, and the stick forces are not too light at low speeds nor too heavy at the greater speeds. The pilots considered them to be a very definite improvement on the Hurricane and Spitfire fabric covered ailerons.
General - There is no tendency for any control to oscillate snatch or take charge at any speed. The pilots considered that with this aeroplane a definite advance had been made in fighter controls."


RAF 71 Squadron was formed in September 1940 at Church Fenton in Yorkshire with American volunteer pilots. They were given three Brewsters, which must also have been 339Bs. The squadron leader was Walter Churchill, credited with 4-plus victories during the Battle of France; he filed this report in October.

"It is strongly recommended that this type should on no account be considered as a fighter without considerable modification.
The wings are not bolted to a centre section but appear to have a common main rear spar located through the fuselage. Changing wings in the event of accidents will therefore be uneconomical and slow.
The elevator is actuated by a push-pull tube. While this is a positive method of operation it is feared than an explosive shell or even a bullet . . . may shatter or collapse it. Experience has proved how much punishment the twin cable can stand without breaking down.
The electric system instead of having dual cables is of the one wire earth return [negative ground] type, which means that a chafed lead may cause fire and will in any case blow the fuse in the given circuit.
The fire power of two .5 Colt and two .303 Browning guns is inadequate.
No reflector sight.
The side panels of the windscreen are at such an angle that it is difficult to see through them.
The armour plated seat is not thick enough or high enough to protect the head. It should stretch from one side of the cockpit to the other. It is submitted that the side panels on the fuselage adjacent to the seat be armour plated in view of the number of arm wounds which have been received in other single seat fighters.
The [primer] is not positive like our Ki-gas and it has a habit of sticking in the off position. It incorporates a rubber gland which perishes and has to be removed.
The undercarriage actuating lever is so small and sharp that it is both difficult as well as painful to operate. . . . The same applies to the flap operating lever. [He didn't like the seat adjustment lever either.]
The top straps of the Sutton harness should be fed through the back of the seat instead of over it. In its present position the pilot is only securely held when right way up. In the inverted position the straps give enough to allow him to hit his head on the hood.
The control column with firing button on top . . . does not give such good firing maneuverability when fighting as the spade grip, with the firing button in the front.
The R/T controls are on the right hand side, necessitating changing hands to operate [the radio], and is so placed that the pilot's elbow hits the seat every time he changes from send to receive.
The oxygen is regulated automatically instead of manually, where the pilot can turn it on a bit more for fighting.
The clock itself is of no value without a trip indicator which this one has not got.
The rudder has only one instead of two control cables. It should have three hinges.
The inertia starter is not so good for quick take-offs as the battery starter.
There is no automatic mixture control with the supercharger in high gear. There is no exhaust gas analyser by which to judge the mixture control.
There is not automatic boost control. This means that in a battle climb the throttle has to be adjusted continuously in order to avoid exceeding maximum possible boost.
The fuel tanks appear to be of the integral type built into the spar. A bullet hole in the tank will therefore mean changing the wings.
The flaps are not large enough and only work for 60 [degrees} of travel, with the result that the glide is somewhat flat and the aircraft trundles a long way on landing.
When landing or taxying the tail wheel wobbles on its caster and rips the rubber of the tyre.
As a trainer the aircraft is delightful. It behaves with the ease of a [Gloster] Gladiator and is just as simple to aerobat. So far we have found no vices."

XyZspineZyX
09-04-2003, 07:58 AM
Salute Masi

Not a crusade.

An attempt to get the aircraft modelled correctly.

Right now it clearly performs much better than it did historically.

Whether you take Finnish sources or Brewster Company sources.



RAF74 Buzzsaw

XyZspineZyX
09-04-2003, 08:03 AM
I'm not doupting your testshttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif
There are many other FM things that need tuning also.
And belive me, BW is closest to reality in FBhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

XyZspineZyX
09-04-2003, 09:37 AM
LeLv28_Masi wrote:
- I'm not doupting your tests/i/smilies/16x16_smiley-happy.gif
- There are many other FM things that need tuning
- also.
- And belive me, BW is closest to reality in FB/i/smilies/16x16_smiley-happy.gif
-
-

Not sure about being THE closest as absolute performance, but at least very accurate when comparing its performance to Brewsters main adversories like Hurricane and early-VVS planes.

Relative performance is what matters most.

XyZspineZyX
09-04-2003, 10:18 AM
i would also ask Oleg to check the sustained climb of IL-2, especially the early series. They climb almost like 109E /i/smilies/16x16_smiley-wink.gif

for the time being, in V1.1b there are several planes overmodelled in climb:

Brewster,
LaGG3 66th series,
IL-2,
La-7 (somebody measured 29m/s at SL),
109G2 (somebody measured 22m/s as average climb from 0 to 5000m, it gives 3:48 min to 5000, should be 4:40 min to 5000m).

Undermodelled are 109G-6s: 16 m/s at SL.

But I don´t know exactly at which power setting these numbers were measured, whether 100% or 110% so take the numbers only as orientation.



<center>http://www.kurita.sk/PRIVATE/pictures/sig_il2.jpg

XyZspineZyX
09-04-2003, 11:44 AM
That RAF guy seems to be right about climbrate. If those gametests are correct then it climbs little bit too fast (error is minor) and maybe it will be fixed. Hopefully there is lots of testflights against I-16 and all other opponents when fixing it, so that relative performance of each plane would be at least near to RL.

But that is only one plane of FB's huge collectionhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif


We have seen lots of differend kind of FM's during the journey from IL2 box version. I'm ready for idea that there would be a game which would not be patched at all. No matter whatkind of FM it would havehttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif At least there would be a stable base for squads training and onlineflying for more than two months.

Generally about the FM's. First check out this trackfile:

http://koti.mbnet.fi/hllv21/bwstart.ntrk

You will notice that i set 110% power and 100%prop pitch when starting and never touch power again. Only thing i have to remember is to take gears up and again down when landing. Also i may use flaps if i remember those when landing.
The problem conserns many planes and not just Brewster. I have been able to fly many succesfull combat missions in VOW just remembering to lower gears when landing. I have used constant 100% prop pitch and constant 110% power during hole missionhttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif
So what?
That this is not possible with real fighter with powerfull engine (not even with cessna152).

I think that this is bigger problem if you are interested of it...
I don't know that will this be ever fixed (maybe it takes whole new sim to fix it, who knows) but currently only thing i have to remember is to start engine, set full power and lower gears when landinghttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif) It is nice that we have complex engine management and all kind of knobs to tune but in longer run it doesn't feel very realistic if you don't need even throttle after takeoff...

More experienced people will realize what this means about FM's...
You just can't get it all at once. Let's be happy with this one.

:Sami







Message Edited on 09/04/0311:44AM by LLv26_Sami

XyZspineZyX
09-05-2003, 06:35 AM
Look at this topic

http://www.vow-hq.com/index.php?page=forum&action=topic&id=1828&PHPSESSID=af1760feb8443c0cca1b81e291c85717

and tried the compare-program found there:
http://www.sukhoi.ru/forum/attachment.php?s=b6219ea0d649831f4e233dceceff8b95&postid=186323

I-16 vs Brewster for example! Whaaaaa???? Brewster loses in every aspect now!! Great work Buzzsaw!!