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Author Topic: Sabre FM Discussion  (Read 5561 times)

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JG14_Jagr

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Sabre FM Discussion
« on: June 08, 2011, 04:24:46 PM »

Obviously a broad topic given the range of Models...  just figured I'd start the first thread :)
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Lt.Wolf

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Re: Sabre FM Discussion
« Reply #1 on: June 10, 2011, 10:10:08 AM »

FM discussion about what?
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Batbomb

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Re: Sabre FM Discussion
« Reply #2 on: June 10, 2011, 12:17:50 PM »

I think he means the F-86 Sabre... but what is to discuss about it? The current Jetpack has the most accurate F-86 FM's EVER. Nothing to discuss about it... its based on original Flight Simulator FM's wich where worked out with the help of real Sabre Pilots. I don't think that there is anything to improve ;)
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SAS~Howlin

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Re: Sabre FM Discussion
« Reply #3 on: June 10, 2011, 01:06:07 PM »

dont feed the troll.
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Far77

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Re: Sabre FM Discussion
« Reply #4 on: June 10, 2011, 10:38:19 PM »

FM discussion about what?
In brief:
Why having about the same as Mig-15bis (or even a little worse for F-86a) sustained turn F-86a had much better horizontal maneuverability in real life and how to implement this into the game
http://www.sas1946.com/main/index.php/topic,15649.msg168711.html#msg168711

http://www.sas1946.com/main/index.php/topic,15649.msg175175.html#msg175175
http://www.sas1946.com/main/index.php/topic,15649.msg174209.html#msg174209
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SAS~Anto

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Re: Sabre FM Discussion
« Reply #5 on: June 11, 2011, 04:34:51 AM »

Won't be doing so today, but some day in the next week I'll dig out all the discussion in the 1956 release thread and drag it here.

As I understand there were two points up for discussion:
a) The 'valenkhza' phenomenon that occurred in some MiG-15s due to manufacturing defects (causing dangerous pitch up stall/spins at low level, due to airframe asymmetries)
b) F-86 horizontal maneuverability

In my honest opinion, if you can't out-turn a MiG-15bis in an F-86E, then you aren't flying it right :) Not the flight model isn't flying right.
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Lt.Wolf

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Re: Sabre FM Discussion
« Reply #6 on: June 11, 2011, 06:21:55 AM »

When going through the beta testing there was some issues raised by CsoCso and another about turn performance or lack of. I offered to take them into a server and had them follow me through certain turns in the correct conditions and they were convinced other wise and agreed that it was them selves.

I again think that this idea of taking people or neigh sayers into a server and dogfighting with them. Not to show if I am better but to test.

On offer.

I do consider that the FMs may not be 100% nothing ever will be. However you must also consider that you may be flying against and ai or your flight knowledge for that aircrafts performance in a turn whilst using that data maybe used incorrectly thusly you are not getting the results you desire, in other words to accuse the FMs of being in accurate you must also be willing to accept that you or who ever may not be flying them correctly until it is further investigated.
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Far77

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Re: Sabre FM Discussion
« Reply #7 on: June 11, 2011, 10:08:50 AM »

There is one more thing which concerns me about Migs and Sabres both. But I don't come to any solid opinion on this. Here it is.
It looks from this "game-tests"
http://www.sas1946.com/main/index.php/topic,15649.msg175054.html#msg175054
that turning with the stick at full corespondes with the sustained turn. It seems for me that if you pull the stick at full then the turn rate should be usually tighter (even with the price of loosing some speed). What do you think?
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Lt.Wolf

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Re: Sabre FM Discussion
« Reply #8 on: June 11, 2011, 11:57:31 AM »

Firstly the problem you guys are having with receiving a bad response from modders over FMs and any thing else to do with the aircraft is the following. Work on these aircraft from 3D, Coding, Skinning and FM have taken many months using most of people's available free time, 1000s of hours not to mention the research. I came to this project late having worked on the original PeterD FMs and knowing the effort put in already on the FMs by these guys and having spotted some problems I offered my help to work with them and rework the FM to what it is now. You guys need to learn the "Compliment Sandwich". Criticism is welcomed, just say what is good about the aircraft first so we don't go and change everything.  :D we only here bad things, if you guys are picking faults at the nitty gritty things then you must be satisfied with the whole picture right?

I just did some game tests with the MiG-15Bis and F-86A-5, these FMs are probably more accurate for all numbers climb, roll, top speed etc than the others followed by the MiG-17 and all other Sabres. This is due to the fact that with limitations of the game, things start to get a little bit more blured, tweaking and trickery to get the values comes as a compromise.

Results of the tests
F-86A
25.33 Turn Time
670Kmh IAS
250m
4.9 Gs

MiG-15
25.75 Turn Time
670 IAS
250m
4.8

F-86A
22.45 Turn Time
520Kmh IAS
250m
4.4Gs

MiG-15Bis
22.68 Turn Time
520Kmh IAS
250m
4.4Gs

F-86A
48.99 Turn Time
6250m
570Kmh IAS
3.4Gs

MiG-15Bis
47.027 Turn Time
6250m
570Kmh IAS
3.4Gs

F-86A
65.25 Turn Time
9500m
570Kmh IAS
2.8Gs

MiG-15Bis
59.82 Turn Time
9500m
570Kmh IAS
2.8Gs

These tests were averaged over 3 turns. As you can see that the lower you get the more closer matched and better the Sabre is than the MiG-15Bis. As you get higher the advantage goes to the MiG and not by a lot until you are over 25Kft, 30Kft and above the MiG out performs much more as to be expected.

Best turn performance for these aircraft range from 520Kmh - 570Kmh IAS

There is going to be an update - The speed brakes are a know issue already, I left them at a high value part of the old FM and people complained before that realistic values in PeterD FM didnt bleed E enough. I must confess that in the original they were half the RL size and now they have been reduced to correct size, just remember that when you apply the brake in a car you have to take the foot off of the accelerator. MiG-17 airbrakes although correct size already, they are more effective than they should be and have been reduced to a more realistic number.

The most important thing with these jets is they have there advantages over one another but are comparable. I have seen people online flying these jets and complaining fo blackout, over G neg G wing rips, and the problem is you are not in a Spitfire or 109.

There is one more thing which concerns me about Migs and Sabres both. But I don't come to any solid opinion on this. Here it is.
It looks from this "game-tests"
http://www.sas1946.com/main/index.php/topic,15649.msg175054.html#msg175054
that turning with the stick at full corespondes with the sustained turn. It seems for me that if you pull the stick at full then the turn rate should be usually tighter (even with the price of loosing some speed). What do you think?

Firstly in documentaries such as Dogfights or historical data the described fights rarely speak of height, speed and pilot skill/strenght so question the data you are reading until it can be backed up by several sources.

The turn depends as you can see above on different factors, aircraft weight, height, speed, enemy weight, height speed etc. If you are travelling at speed then your G you are pulling is higher, energy bleed higher, turn circle wider and time is longer, blackout occur. There have been reports of aircraft that are not know for being turny out turning another simply by using a high yo-yo. Another factor in the fight which is one of the most important advantages in my opinion when it comes to dogfighting jets is the thrust to weight ratio. The MiG has a much higher thrust to weight so its engine can push it around turns at lower speed better, better thrust to weight means you can recover from a turn fight quicker and trade the E for verticle fights where you will kill a Sabre straight away after a turn fight or use it to out accelerate.

From tests you can see that the aircraft are similar and have their advantages, you just need to change your attitude and fight differently, energy fighting. Here is a few good and bad points to consider in human vs human.

MiG-15Bis Better climb, Better acceleration, holds energy, better thrust to weight can recover from fights well, climbing turns beat Sabre quickly but Sabre turns better before it will stall.

F-86 Sabre good zoom climb, better dive speed, better deceleration with brakes, bleeds e well. Good in the horizontal, energy must be kept high and not baited into sustain turn fights, always leave enough E to trade for a loop. Split Ess will pull more G and tighter turns, MiG will black out in such a high speed turn.

The 'valenkhza' phenomenon - There are limitations on how much of the aircrafts airframe you can design and it remains symmetrical, we are aware of this affect, the FM is based on how the designers intended it to be without the production flaws. Adding those random flaws is something that has to be implemented using Java not via FM and amount of affect could be applied randomly.

I was in favor of using a more complex/realistic engine characteristics but was out voted.

Hope that helps with some of the issues.
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Far77

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Re: Sabre FM Discussion
« Reply #9 on: June 11, 2011, 12:37:51 PM »

I should clarify. I write about the matter not because "I can't shoot damned Migs/Sabres..." but for historical/technical accuracy. I am interested in the game from this aspect first (for example I use a keyboard to play a little...).

I can repeat what I wrote many times - current Mig model is the best I  saw... Hoping to help make it even more better.

It would be nice to have the "random-force" valezhka.

If you need some more technical info on Mig-15/17 (like for example, its deceleration with airbrakes)- please let me know and I will try to check manuals.

Thank you for the game!
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Lt.Wolf

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Re: Sabre FM Discussion
« Reply #10 on: June 11, 2011, 02:02:43 PM »

Deceleration would be useful thankyou and any thing else
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Far77

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Re: Sabre FM Discussion
« Reply #11 on: June 11, 2011, 10:19:23 PM »

From the 1953 Mig-15 manual.
Mig-15bis
airbrakes total square =0.5sq.meters.
maximum angle of deflection = 55degr.

In 1952 (year) version of production Migs total square was 0.8  sq.meters (Mig-15bis data is given for 0.5sq/meters)

DECCELERATION WITH airbrakes 0.5sq.m from Vmax to 0.7*Vmax
Engine idling unless otherwise stated.

H=2km --> 0.7min (engine at full thrust)
H=5km --> 0.42min
H=11km --> 1.02min

WITHOUT airbrakes
H=2km --> 0.74min
H=5km --> 0.96min
H=11km --> 1.87min

Speed IAS decrease (kph) from Vmax for 30seconds WITHOUT airbrakes
H=2km --> 198
H=5km --> 139
H=11km --> 51
Speed IAS decrease (kph) from Vmax for 30seconds WITH airbrakes
H=2km --> 236 (engine at full thrust)
H=5km --> 271
H=11km --> 79.5
-------------------------------------------------------------
Data on Mig-17a (from the 1971 manual on Mig-17)
airbrakes total square =0.88sq.meters.
maximum angle of deflection = 55degr.
(first production version has total square 0.52sq.m  and maximum angle of deflection = 50degr.)
DECCELERATION WITH airbrakes 0.88sq.m from Vmax (1042kph for H=10km, 1094kph for H=5km) to 0.7*Vmax
Engine idling unless otherwise stated.

H=5km --> ~0.3min
H=5km --> ~0.93min (engine at full thrust)
H=10km --> 0.5min
H=10km --> ~2.2min  (engine at full thrust)

WITHOUT airbrakes

H=5km --> ~0.83min
H=10km --> ~1.26min

========================
There are much more data in the manuals (see links below). Some of the data is rather specific - just for experts (for example I don't completely understand what it means).
If you download the manuals and would like to ask "what does it mean in English" I (and probably some other forum visitors) would be glad to try to help with translation.

Techical manual for Mig-15bis (in Russian) can be downloaded from here:
http://1.airwar.z8.ru/bibl/mig15bis_to.zip

Data on Mig-17a (in Russian Mig17 usually means Mig-17a) is in a techical manual (in Russian) which be be downloaded from
here:
http://1.airwar.z8.ru/bibl/mig17to.zip

Online version of the 1955 manual  on MIG-17 and some Mig-17 versions with an afterburner can be obtained from
http://www.aviation.ru/Leonid.Mehanikov/MiG-17_Flight_Manual/contents.htm .



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