Possible too slow roll rate.

I knew that roll rate for the k4 was about 4.5 seconds at 200-250 miles/hour or slower .Without rudder.

Regardless of speed i can't roll it quicker than 6 seconds or so in game.Again without rudder.

Is this just me ?

 

 

"Roll performance is similar to a Hurricane or elliptical wing tipped Spitfire. A full stick roll through 360 degrees at 460 kph [=285 mph] takes 4 to 4.5 seconds without using rudder, and needs a force of around 20 lbf. "

- Dave Southwood, test pilot.

 

This is probably E4 but AFAIK difference in roll rate between Emil and Kurfurst is minimal .

 

There was a diagram on ww2 aircraft performance with lots of roll rates but couldn't find 109 on it.

Should be a little worse than Full wing spitfire 9 (3.8 4 seconds) Afaik.

 

Is this just me guys?

Edited April 20, 2016 by otto

I compared the roll rate of the 109 in game to p51.Which should be similar at certain speed:

 

109 G:

"The roll rate is very good and very positive below about 250 mph. Above 250 mph however the roll starts to heavy up and up to 300 or so is very similar to a P-51. After that it's all getting pretty solid and you need two hands on the stick for any meaningfull roll rates. Pitch is also delighful at 250 mph and below. It feels very positve and the amount of effort on the control column needed to produce the relevant nose movement seems exactly right to me. The aircraft is perfectly happy carrying out low-level looping maneuvers from 300 mph and below. Above 300 mph one peculiarity is a slight nose down trim change as you accelerate. The rudder is effective and if medium feel up to 300. It becomes heavier above this speed but regardless the lack of rudder trim is not a problem for the type of operations we carry out with the aeroplane."

- Mark Hanna of the Old Flying Machine Company flying the OFMC Messerschmitt Bf 109 G (Spanish version)

 

 

 

 

 

 

P51 roll rate in game is 5-5.3 seconds .As far as i can tell should be more like 4 seconds at 300 mph. 109 roll rate is at least 6 seconds and should be closer to p51 at speeds lower than 300 mph.

You are kind of comparing apples to oranges here. The chart shows a P-51B which has different wing root chord and less mass in its wings than a D variant. For example the D has 3 .50s compared to the 2 .50s of the B. Also the chart is for IAS, so you would have to adjust for instrument/ position error.

 

Now for the 109 its really hard finding data on the rollrate. There are a few russian documents around and then there is the DVL data. Which was measured on a 109 F-2. This chart gives a maximum of ~82°/s at 550 kph, 3km height. There is a good chart by Ze Hairy on the BoS forums. These data are for TAS btw so dont confuse it with the NACA data above. Also it needs to be noted, that wing stiffness increased for G and K models, so the rollrate will be slightly higher. If the aileron deflection angle or mechanism changed as well I cant say from the top of my head.

Did you try it at 3000 m and with 500 km/h ? Both speed and altitude has its effect on the max. rate.

 

Increasing altitude also slightly increases roll rate (because of less dense air I suppose), though it cannot possible account for 50% difference in this altitude range.

 

p.s. the devs already have this report in full.

So, i've a question : How can you explain that a lot of 3rd Reich 109 fighter pilots prefere the Freidrich and early Gustav versions to the all mighty (don't get wrong about ''all mighty'', it's just my personal opinion ;)) G-10 and K-4, because of the lack of maneuverability of those last Bf-109 ?

 

I ask this question because one of you, Otto, said : ''This is probably E4 but AFAIK difference in roll rate between Emil and Kurfurst is minima.''

Edited April 21, 2016 by Jowen G. Bruère-Dawson

I just tested at ICAO ISA, 3000 m 550 kph TAS and got a roll rate of about 5.5 s/turn. That would be just short of 65.5 °/s. Now I dont have the full DVL report so I cant say much about the fuel load etc. If you could post it Kurfürst I would be glad. Also I dont know how strong the pilot is in DCS.

 

They talk about turning capability, because in general the heavier the plane the worse its turns. Roll rate is a completely different horse. While you would have worse turn radius with higher wing loading you will actually increase roll rate. One cant compare Doras-Emils to later variants though. Different Wing different roll characteristics.

Edited April 21, 2016 by rel4y

I just tested at ICAO ISA, 3000 m 550 kph TAS and got a roll rate of about 5.5 s/turn. That would be just short of 65.5 °/s. Now I dont have the full DVL report so I cant say much about the fuel load etc. If you could post it Kurfürst I would be glad. Also I dont know how strong the pilot is in DCS.

 

They talk about turning capability, because in general the heavier the plane the worse its turns. Roll rate is a completely different horse. While you would have worse turn radius with higher wing loading you will actually increase roll rate. One cant compare Doras-Emils to later variants though. Different Wing different roll characteristics.

 

600 kph = 91 deg/sec (1.6rad) - peak value for DVL evaluation 109F2 .

So, i've a question : How can you explain that a lot of 3rd Reich 109 fighter pilots prefere the Freidrich and early Gustav versions to the all mighty (don't get wrong about ''all mighty'', it's just my personal opinion ;)) G-10 and K-4, because of the lack of maneuverability of those last Bf-109 ?

 

I ask this question because one of you, Otto, said : ''This is probably E4 but AFAIK difference in roll rate between Emil and Kurfurst is minima.''

 

Depends on personal preference .I like the fw A a lot more than the d9.Some would prefer to fly d9 .

Same with ww2 109 pilots. I would say the g14 would be the best for me.

600 kph = 91 deg/sec (1.6rad) - peak value for DVL evaluation 109F2 .

 

No 1.42 rad/s -> ~82°/s (if in question always look at "gemessen") ;)

Understood, thanks

No 1.42 rad/s -> ~82°/s (if in question always look at "gemessen") ;)

 

That was ze hairi's post i found on the web. :D

I use 2*pi radians=360 degrees and Cross-multiplication.

I am not sure I get what you are saying. Your calculation is correct, you just need to look at the right curve. (gemessen) :o

Edited April 21, 2016 by rel4y

So, i've a question : How can you explain that a lot of 3rd Reich 109 fighter pilots prefere the Freidrich and early Gustav versions to the all mighty (don't get wrong about ''all mighty'', it's just my personal opinion ;)) G-10 and K-4, because of the lack of maneuverability of those last Bf-109 ?

 

I ask this question because one of you, Otto, said : ''This is probably E4 but AFAIK difference in roll rate between Emil and Kurfurst is minima.''

 

The Bf 109 put on a lot of weight going from the F-4 version to the K-4, along with vastly increased power output: up to 1450PS for the F-4, compared to the K-4's 1800-2000PS. Obviously more power means more prop torque. The roll rate pretty much stayed the same, but the plane's turning performance and pleasant handling were reduced.

 

Many RAF pilots also said they preferred the Spitfire Mk V to the much more powerful Mk XIV version. Its a similar situation to the 109: the Spitfire went from around 1300hp in the Mk V (depending on engine version) to around 2000hp in the Mk XIV and put on a heap of weight. The plane didn't fall behind on roll rate, but its other handling characteristics were made worse by the extra weight and power.

The DVL report however is in principle applicable, as it shows measured sustained angular velocity including roll inertia and sideslip.

 

Difference being here the model F-2 vs K-4. For which one has to consider different mechanical/structural features of the wing, different center of gravity, mass and power output. Also the maximum stick pressure of the DCS pilot has to be considered at higher velocity. A lot of hard to tell variables going on here and I have not yet seen the full DVL report.

 

Now mass increase (max 350 kg close to the center of rotation) and COG should only have marginal effect. Power settings can be manually adjusted once known, therefore the engine torque can be closely replicated.

Structural improvements and mechanical changes would lead to a stiffer wing and different de facto maximum deflection angles of the ailerons. Thus possible increasing rollrate, though the margin would be pure guesswork.

 

Not easy at all.

Hey guys!

 

So I tested a bit today and measured average time for a complete roll after about 45° of initial roll to ignore the time of acceleration to maximum roll rate. Weather was set to ISA conditions, starting altitude was 3050m, 500 kph TAS, engine was set to 1,0 ata, fuel was set to 5% and infinite fuel in the menu, MW50 was set to empty and total aircraft weight was 3001kg in the ME. I choose 500 kph because the DCS pilot strength is unknown and 20 kg (44 lbs) should not be limiting.

 

The aircraft weight for a fully loaded F-2 is stated as 2728 kg in this document (kurfurst.org/Performance_tests/109F1F2_Kennblatt/Kennblatt_fur_Bf109F1F2_DB601N.PDF).

 

So the weight difference between the tested aircraft is 273 kg.

 

The time for a full roll to the left averaged 5.5-5.6 s and to the right 5.1-5.2 s. Altitude loss for a full roll amounted to about 150-180 m. I tested 6 times in each direction and measured the time while reviewing the track. I didnt touch the rudder and had elevator trim set to -2.

 

The DVL report states an angular velocity of ~1.4 at 500 kph TAS. That is about 80°/s, so for a full 360° turn it would take an F-2 4.5 s at 500 kph TAS. From what I could gather the Frise type ailerons remained unchanged from F-2 to K-4. The wings were apparently strengthened for G & K in comparison to F models which would in turn mean less wing twist.

 

Is there any reason that a K-4 should roll about a second slower than a F-2 with a weight difference of 273kg?

You mean a reason apart from a different wing, different and powered up engine and increased weight and wing load from the lighter of the 109s like the F was? No, definitely no clue.

 

S!

The different wing should make it roll faster, different engine is totally irrelevant if torque is the same, for wing loading please read the first page and since that goes hand in hand with weight, weight increase is near center of rotation.

Edited April 28, 2016 by rel4y

Is torque the same with 1200 and 1800Hp?

 

Yeah, Emil and K 109 should perform the same roll rate, definitely. You're the expert but I don't see why increased wing load should enhance roll rate instead of downgrade it. Also I don't see why XXL size wing bulges (holding extra sized tires and rims and extra wide landing gear, that's weight in the wings) should help. Any light on that?

 

S!

Where am I talking about Emils? Engines can be set at only at full power? How do wing bulges affect roll rate? I think landing gear is the same width as for the F models.

 

Now the weight of the tires is reasonable and I actually havent thought about it. But we are talking 20% decrease of rollrate here. I am not saying its incorrect, I am merely asking for ideas.

Edited April 28, 2016 by rel4y

Where am I talking about Emils? Engines can be set at only at full power?

Sorry, you said about thread start and started with that, but you're right :smilewink:. Well you can set engine in many powers but I don't know if DB601 and DB605 should have same torque with same Ata setting (not to mention quite a different wide blade propeller also).

 

 

Now the weight of the tires is reasonable and I actually havent thought about it. But we are talking 20% decrease of rollrate here. I am not saying its incorrect, I am merely asking for ideas.

Actually K also wears extra weight from extra gear covers and retract mechanism. Usually extra covers were removed indeed but our model is a brand new and complete one. And Fug antenna, may be some equipment, was also there. Neither I say it's right or wrong, I don't know K4 roll rate performance charts, but makes sense to me the heavier 109 model loses performance from the lightest F2 model (I don't count Emil here being actually a different aircraft).

 

S!

Is torque the same with 1200 and 1800Hp?

 

Yeah, Emil and K 109 should perform the same roll rate, definitely. You're the expert but I don't see why increased wing load should enhance roll rate instead of downgrade it. Also I don't see why XXL size wing bulges (holding extra sized tires and rims and extra wide landing gear, that's weight in the wings) should help. Any light on that?

 

S!

 

I'm just looking to find out more.

Bulges on wings are irrelevant to roll rate.Aileron design,and force moment are more important.

Fw 190 V1(prototype) roll rate was 162° per second at 410 km/h. Roll rate remained the about the same for all Fw 190 A (table 868 previous page) even if they had a lot more mass with wing cannons and such.

Roll rate changed with d9 because of the shift of center of gravity .The changes were substantial compared to A model. Plane became more stable and rolled slower some say.Some, think it rolled same as Anton.

I just looked at the first page and indeed I mentioned the Emil, but that statement still stands true!

 

One cant compare Doras-Emils to later variants though. Different Wing different roll characteristics.

 

I used an ata setting (just below 1 ata) at which I could sustain 500 kph, the F-2 graph shown is for Steig und Kampfleistung I believe. Now I dont know how much torque a F-2 with its DB 601 N engine produces at 1.3 ata (2400 rpm, 1020 HP MSL), but I figured the torque produced by a DB 605 DB at sub 1 ata should not be higher (engine output below 1000 PS). At 1.45 ata the DB 605 puts out 1430 HP (MSL).

 

I believe the lengthened tail on the dora and inline engine compared to radial engine will have the highest effect. Do you have by any chance a figure for roll rates of different FW 190 models so we can compare how weight influenced this?

Edited April 28, 2016 by rel4y

I believe the lengthened tail on the dora and inline engine compared to radial engine will have the highest effect. Do you have by any chance a figure for roll rates of different FW 190 models so we can compare how weight influenced this?

Sorry mate, not right now. But sure there will be something at Kürfurst web.

 

S!