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WWMaxGunz
10-18-2005, 01:27 PM
I really do like the pre-stall buffets.

And I do see nice that AOA does mean more now, not a big swing but a small change.

However I am still finding that I need to know more about power, thrust and AOA.
Maybe too what kind of full power stall speeds these planes were capable of.

Should I be able to climb at 130 and 140kph IAS in 109G-6 Late and La5FN?
Not run level or very little climb but watch altitude click by +10m every few seconds?
Few as in not many, you try. Hardest part is not rolling over, easier in La than Bf.

Somehow I thought that climb is a power thing and induced drag should eat that but hey,
there must be way more thrust than I think even at such sppeds, even over 3km altitude?

Hey, just curious and not using the B-word that ends in G. I am not 100% sure so I ask.

faustnik
10-18-2005, 01:45 PM
Neal,

I also have some questions about low speed climb. My impression from reading a lot about the subject, is that high powered prop fighters had serious torque issued at high power settings at low speeds. In PF all a/c can climb at full power at super low speeds without even rudder input. Is this realistic?

WWMaxGunz
10-18-2005, 05:11 PM
I tried the P-51C and was able to climb at 160kph, even very slowly at 150 on the speedbar.
But then that's not much slower than good takeoff speed though at takeoff the plane is not
pitched upward so steeply. I doubt that running a real P-51C with the default load in PF
at 100 mph and 90% power would have been a bright idea, but would it have been able to climb?
Maybe so. I can say it was hard to keep it from rolling but then this joystick I have is
about shot, I had to put in about 40% deadzone on the twisty to get the rudder to center
when I let loose in calibration. No deadzone on the other axes as they're not so far off.
Maybe new springs would really help but it's a Logicrap, could I even get new springs?

Are the Saitek X-45's okay or do they have problems with IL2?

If I could get a stick made that used a mouse inside, could I program the HOTAS to see that?

JG5_UnKle
10-18-2005, 06:09 PM
Yep this one is a golden oldie, low speed climbs have been iffy for a good long while.

Basically Faustnik - erm... no it isn't realistic. I just don't buy an aircraft like the K4 being to go full power at 160Kph and keep it pulling into a climb.

Big-*** radials like the the R2800 should throw some serious torque into the mix... the list goes on.

I'm not sure about the stability thing, but the lack of torque is clear. I'm not sure what Olegs thinking is, maybe it's a side effect of other properties, like reduce the weight of a/c = Low speed climb goes up etc.

It would be good to measure low speed vs High speed climb rates. Try a G6 at say 270Kph and then try it at 250 and 290 and 320 etc.

JG5_JaRa tested this back in the day and you should see the chart below.

http://aa.1asphost.com/pinetrees/crd2.JPG

If we could test some more maybe we would see if this effect has changed http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Kuna15
10-18-2005, 06:11 PM
@ WWMaxGunz If you seriously think about X45 you better have some pedals for rudder, or else... you wont be able to handle the plane properly. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I have X45 and Cyborg EVO. Currently X45 (brand new, I used it for about one month, untill I get myself EVO) is collecting dust and I'm using EVO.
X45 rocker rudder is simply unusable as good rudder control IMHO.

faustnik
10-18-2005, 09:25 PM
Originally posted by WWMaxGunz:


Are the Saitek X-45's okay or do they have problems with IL2?



I know a lot of people that have problems with the X-45. I'm sure there are a lot that think it is great though. You might want to take your time and really research the available setups.

I wouldn't change my MSFFB2 stick for anything, I even have a spare on the shelf. You can still find them on E-Bay.

faustnik
10-18-2005, 09:29 PM
Originally posted by JG5_UnKle:


Basically Faustnik - erm... no it isn't realistic. I just don't buy an aircraft like the K4 being to go full power at 160Kph and keep it pulling into a climb.

Thanks Uncle. I have a problem with that because light a/c can climb at high AoA forever with plenty of control. This results in an advantage over a/c that must B&Z. The light a/c can just point its nose at the B&Z plane and get a shot any time.

p1ngu666
10-18-2005, 10:31 PM
i think its harder todo that than before.

il2I dies in the vertical

the hang on the prop trick was a spitfire late mark trick (especialy), but then those where effortless in teh climb, anyone whos been to duxford can tell u that

true of japanease planes as they are light, and probably 109s too

just general interceptor thing really

in the "interceptor" missions ive run on HL germany is best so far, russia second and america 3rd

there not identical, i should probably standize them. britain, japan, italy, poland yet tobe made or run.

WWMaxGunz
10-19-2005, 08:59 AM
Yeah, I can't get away with as much when trying things I think may be impossible.

A Definite Improvement from my POV.

Since I don't know exactly where the line is regarding full power at lowspeed with
these planes, I don't know when to say "please more change" and when it may be so
close the next step may be pleasing but not real. I've never handled such power in
props and never handled a plane in such regimes myself and don't have data there
either. The only sims I've flown in those ways, may not be valid there either so
what is left but to ask those who should or can *know*.

Perhaps to recreate in-game climb at speed curves the answer will become more obvious
as such are available for at least some of the planes. The shape is I think more
important than exactly the data points, but a big shift up or down is also not great.

No matter what, I feel that things have gotten some better in this area at least.
It is nice to feel forward progress... are we there yet?

JG5_UnKle
10-23-2005, 11:01 AM
Originally posted by WWMaxGunz:
I've never handled such power in
props and never handled a plane in such regimes myself and don't have data there
either.


Well to be fair me neither, I don't think the Chipmunk counts http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif
http://www.littleafrica.co.za/images/RAF%20Chipmunk.jpg

Viper2005_
10-24-2005, 08:42 AM
Originally posted by faustnik:
Neal,

I also have some questions about low speed climb. My impression from reading a lot about the subject, is that high powered prop fighters had serious torque issued at high power settings at low speeds. In PF all a/c can climb at full power at super low speeds without even rudder input. Is this realistic?

Well let's do some sums.

Spitfire IX

~1700 bhp @ 3000 rpm/+18 psi

With a reduction gear ratio of 0.466 this turns the prop at 1398 rpm.

This results in a torque of 8661 Nm or 6388 lb-ft.

To maintain level flight the wing must supply an equal and opposite rolling moment.

If we assume that this takes the form of a point load acting at the wingtips, then in the case of the Spitfire, with a wingspan of 36'10" we end up with a force of 174 lbf acting at each wing tip.

Considering that the aeroplane weighs about 7500 lbs, the extra lift required from the critical wing only amounts to a 4.6% increase in the lift required (or a 2.3% increase in the stall speed if we're aileron limited).

Torque isn't quite as dramatic as you might expect.

The critical case is takeoff where a significant differential load is applied to the undercarriage.

IMO in flight however, propwash effects are probably more significant - they're certainly the only reason to apply significant rudder with power (unless you're correcting wing-drop at the stall).

JG5_JaRa
10-24-2005, 03:38 PM
Originally posted by Viper2005_:
Considering that the aeroplane weighs about 7500 lbs, the extra lift required from the critical wing only amounts to a 4.6% increase in the lift required (or a 2.3% increase in the stall speed if we're aileron limited).

Torque isn't quite as dramatic as you might expect.

That's a bit oversimplified: not the whole wing counters torque but rather the aileron section alone. If that section contributes (just a humble guess) 1/3 of the whole lift and you place the center of lift of that section at 2/3 of the wingspan, then the torque already eats ~20% of the level flight lift of that section. This gets noticeable as the maximum available aileron torque decreases with airspeed.

However, the horizontally asymetric thrust distribution of the propeller disc due to the superposition of the propeller pitch angle and the aircraft AOA leading to different propeller AOA for the blades rotating upwards on one side compared to those rotating downwards on the opposite side ("P-factor") can, as reported, overcome full opposite rudder effectiveness in a slow and steep high power climb. This is noticeable in the game for taildraggers during takeoff roll as long as the tail is still down, takes quite some rudder to keep them straight as expected, but once airborne the effect is practially gone and can only be seen when carefully observing the instruments. It would be interesting to see that one coming as it is one many good reasons why in real life, WW2 fighters in combat didn't hang on the prop near stall speed all day.

Another problem in slow speed climbs in this sim is that generally, the thrust-drag difference at slow speed is too high, i.e. too much thrust and/or too little induced drag as can be seen by the excessive slow speed climb rates compared to real data. Due to the restrictions of the propeller, thrust can't approach infinity as speed goes towards zero, as would be needed to keep the engine power output constant. The converted power at low speed should drop significantly.

Viper2005_
10-24-2005, 05:48 PM
Certainly it's a gross simplification, but I don't think that the conclusion is incorrect.

Taking your 20% figure, it follows that aileron authority will become insufficient at ~ 1.095 Vstall in level flight.

Still not a dramatic effect.

In unloaded flight, aileron effectiveness will be sufficient to counteract torque at quite surprisingly low airspeeds.

Torque simply isn't the bogeyman it's made out to be, largely because most fixed wing aircraft run their props at reasonably high rpm.

The real demons are propwash, and as you point out, P-factor.

WWMaxGunz
10-24-2005, 10:18 PM
La5FN and 109G-6 Late climbing (slowly but not too slow) with speedbar at 130kph.
That's with less than 100% power, btw. 90-some percent.

That's right about 80mph. You won't take off at that speed but then you don't get
that much AOA on the runway past tail up.