FMs for Nov 2008 version

[Mike Dora 171]

Hi Mike, I think mine are generally the same, but maybe more variation then TKs. Some of mine would be more like that, some less like that.

 

Just some more general comments :)

 

Although I agree with what you are saying (see below), my thoughts are that in real life these planes would have been thrown around quite a bit in dogfights, at least by 1917, and strong rudder would have been a part of evey manoeuvre. Despite some feeling that these planes fought in a sedate leisurely slow manner, I don't believe it. These planes were probably easily the most manoeuvrable planes flown in any war. And most were robust.

 

Its very unlikely these planes would lose wings etc from sudden extreme manoeuvres, or even say very extreme violent spins going for several thousand feet (tho engine recovery may have been difficult) - these don't cause the extreme stresses (high g's) on planes like for example pulling out from a high speed dive sharply. Sure some planes that first went into action had problems - as in every war - but many got sorted relatively quickly (except Nieups).

 

I'd guess a typical WW1 tactic would be to dive out of trouble, as in all wars. In real life I think what would happen is firstly the attacked plane would often dive then exit and survive to fight another day. The attacker probably would be wary of following a plane into a steep dive esp to low altitude - losing his wing mates, losing altitude advantage etc, being followed down by another EA (common). None of these actually are the case in the game, eg, a plane that dives comes back up to fight again, you can always find wing mates, dogfighting altitudes are too low in the game generally compared to what was happening in late 1917, 1918.

 

So its all a bit of a compromise, and if they didn't do extreme defensive manoeuvres in the game they are too easy to shoot down. Lots of compromises in this game, lots of compromises in every game.

 

 

Peter,

 

I've been thinking again (bad habit, I know, but can't seem to shake it). When you edit a Flight Model, which sections of the *DATA.INI file do you edit? Is it just the "FlightControl" bit, or the "AIData" too, or the "Dogfight*" sections too, or do you also edit the individual components' parameters?

 

I ask because I have edited all my FMs to adjust the strength and breakability of all the major airframe components, to give what I think is the best trade-off between target robustness, and bits flying off (the vanilla FE model was far too prone to airframes disintegrating after too few hits IMHO).

 

So what I'm thinking, is that if you _don't_ edit the component parameters, it would be relatively straightforward for me to copy in the bits you _have_ edited, so that I could benefit from all your good work while retaining my own versions of the damage effects.

 

Thoughts?

 

Mike

[+peter01 2]

FMs for Thirdwire's planes?

 

Generally most FMs are changed throughout, exception is a few of TKs, and its best then to add you changes to my FMs.

 

I stared responding but then realised that specific answers depend on which version you are using.

 

So, which version are you using?

[Mike Dora 171]

FMs for Thirdwire's planes?

 

Generally most FMs are changed throughout, exception is a few of TKs, and its best then to add you changes to my FMs.

 

I stared responding but then realised that specific answers depend on which version you are using.

 

So, which version are you using?

 

Thanks Peter,

 

Actually that answers my question.

 

The version I am using is the Nov 08 patch, but with your latest flight models for all relevant ac, whether TK or 3rd party, modified again by myself to adust the main components' resistance to combat damage (and also to G effects in certain cases, eg sesquiplanes' lower wings. Setting the latter's G limits to lower than the ac's overall G limit can lead to some interesting consequences during eg hard pullouts.. )

 

But I'm not going to make any further changes in the near future. As I write, my home PC is in the office with me, on its way to a computer repair facility at lunchtime to try to get the @#$%&^%@* C drive working again.. as of this w/e the blasted thing developed an "error loading OS" problem.

 

Good job I backed up a recent FE configuration. Now I only have to remember where!

 

Mike

[+Tailspin 3]

Peter. Is there any difference between the Oct. "b" patch and the Nov. patch? I had already started fiddling with the Oct. patch and never installed the Nov patch because the readme only states the Nov. patch fixed the quick mission CTD.

[+peter01 2]

Peter. Is there any difference between the Oct. "b" patch and the Nov. patch? I had already started fiddling with the Oct. patch and never installed the Nov patch because the readme only states the Nov. patch fixed the quick mission CTD.

 

I started doing the newer lot on the Oct 2008 version, then changed to the Nov 2008 version, and tested for changes extensively - have become a bit paranoid I guess . I don't think there is any difference in FMs and AI at all.

 

But whether there are other changes, don't know. Wouldn't be surprised though.

Edited February 25, 2009 by peter01

[+Tailspin 3]

Ok, thanks. It does rewrite everything though. Thats why I didn't bother with it.

[Ronbo 0]

Peter,

I noticed that there is only 1 spad 13 data file in your fms campaign for sept 08. the engine type shows 235hp Hispano but goes in the 220 folder? what about the 200 and 235 data files? did i miss something? or is it used for all 3 types?

[+peter01 2]

There is only one folder for the Spad13, so yes, one for all three.

Edited February 26, 2009 by peter01

[+Geezer 3,569]

True. Its the speed at which maneuvers are initiated. This is why care while diving is emphasized. The faster you are going the higher the potential G load. The manual says to initiate the loop at speeds above 75 mph. As Peter points out looping can be a relatively benign maneuver...unless, as the manual warns, the pilot is careless and with the controls. Don't forget also the Tripe was an exception in that it had an adjustable horizontal tail plane that enhanced vertical maneuvers.

 

Were these planes maneuverable? Yes. Indestructible during maneuvers? Still don't think so. Terms like robust are relative to the times. The Dauntless dive bomber of WWII was reportedly capable of pulling 12 Gs without failure. :)

 

I have followed this thread with great interest and finally found an old Air Enthusiast article that might be a LITTLE help. It might also muddy the waters too!

 

The article was an engineering analysis of WW1 single spar sesquiplane designs, with particular emphasis on the Albatross D.5. The article examined the dynamic loads imposed on Nieuport and Albatros aircraft and concluded that they were little better than death-traps in anything more than gentle dives. The author constructed a finite element model of the Albatros D.5 wing structure to illustrate the problem of lower wing flutter that was inherent in both designs. Note that flutter was not even recognized as a problem in WW1, let alone understood by engineers of that time.

 

Basically, the single spar sesquiplane wings failed due to SPEED, not G-loads. Acknowledging that his finite model was a bit of a WAG, the author estimated the failure speed to be anything from 118 mph to 135 mph for the Albatross D.5, and also stated that the Nieuport would have been roughly the same. The wings would flutter and literally twist off the airframe before exceeding their load factors (shot of finite element model below).

 

In one sense this only makes your efforts harder, but in another it may help you. This modern analysis confirms the conclusions you have come to about diving speeds, based on your reading. Very few WW1 aircraft could be dived at high speed - dynamic loads such as flutter would literally tear them apart before reaching their theoretical maximum load factor. Two exceptions specifically mentioned in the article were the SPAD 7/13 and Pfalz D.3 which would only develop flutter problems when their speed approached 300 mph. Even the aircraft that were considered structurally strong in WW1 (Fokker D.7, SE.5, etc) would experience flutter problems above 150 mph.

 

I don't know how much help this is, but I thought you might appreciate the information.

 

[+peter01 2]

Good post and interesting article.

 

Just some rambling thoughts, strictly my own, to add to the discussion.

 

I'd agree that the Nieuports, Alb D3 and Alb D5 probably did suffer from flutter. As you state, they are all sesquiplanes. The lower wings were weak, and/or the single v-strut was insufficient or not sufficiently reinforced.

 

Flutter due to fluid motion is true even of relatively rigid structures such as bridges and buildings. It is certainly true of all aircraft, but generally at higher speeds - it was a major problem in the post ww1 period right through to ww2, and beyond. P47s suffered from flutter - on elevators I think from memory at very high speeds - the P47 of course was about as robust as you could get. But flutter is also related to the strength/rigidity of structures, as well as control surfaces in planes - control surfaces can start twisting moments in planes.

 

I believe the term "flutter" was coined in ww1. Although it wasn't well understood., and impossible to design against generally, designers were aware of what could cause flutter, and how to minimise the effects. The first theoretical research on flutter was started in ww1.

 

The N11 especially was an incredibly nimble plane (to me, possibly as maneuvrable as the Camel or Dr1), so very successful despite its shortcomings, until diving, robustness ceiling and climb (in case of n11) became more important factors in aerial warefare. So Nieuports stayed and were successful until a time when other factors made them obscolescent.

 

Pilots flying the Alb D3 during its peak ascendancy period jan-apr 1917 were told not to dive the plane. This structural weakness was later fixed. The later Alb Dvs did not have the flutter problems of the earlier ones. All relatively, of course, they were just more robust not simply robust.

 

The dr1 initially probably had flutter problems as well but in its case due to its ailerons - also fixed.

 

I'd agree that ww1 planes couldn't or didn't dive very fast, but not because of low flutter speeds alone. Due to the fact they had design dive speeds like every plane ever designed that pilots would have adhered to generally. Many planes could never achieve high speeds in dives anyway because of their design and/or drag - ww1 planes on the whole were not aerodynamically streamlined.

 

I'd be surprised if any ww1 plane could achieve a 300mph dive. Mainly due to drag.

 

I'm surprised that the author believes that the Se5 could only achieve a 150 mph dive safely. It was not a sesquiplane. It was considered robust, many pilots have written of taking planes considered less robust into dives of 180mph. It was ceratinly both powerful and heavy enough to achieve 150 mph very easily.

 

In FE as in most/all games you can't model flutter. Nor max dive speeds unfortunately. After Tailspin pointed out that you could get any plane to dive at 200-220 mph, I realised that Thirdwire has modelled this incorrectly. Some planes should not be able to dive beyond 150 mph (or even less), some probably could attain speeds 220-230 mph. Flutter or no flutter. The parameter that should control this doesn't work for a player flown plane - "MachLimit". It seems to work somewhat for the AI, if thats a consolation.

[+Geezer 3,569]

Pilots flying the Alb D3 during its peak ascendancy period jan-apr 1917 were told not to dive the plane. This structural weakness was later fixed. The later Alb Dvs did not have the flutter problems of the earlier ones. All relatively, of course, they were just more robust not simply robust.

 

Thanks for responding. I really don't have a position one way or another, I simply thought that you guys might find this information of some interest.

 

FYI, the techniques employed by the author - an aeronautical engineer - for modeling aero elasticity have only been in use since the 1960s, as the phenomenon is extremely complex and requires extensive computer horsepower to model accurately. The finite element model was constructed using industry standard techniques that employ MSC NASTRAN, a program originally developed by NASA, and referenced semi-empirical flutter analysis by the well known French engineer Professor Y Rocard. The original static load factor of the Albatros D.5's lower wing was only 1.2, and Idflieg requested an increase in strength to 1.7 which was confirmed in tests conducted in April 1918. Additional modifications improved the static load factor further to 2.5, but this was still inadequate when compared to the 5.3 static load factor of the Albatros D.1 of 1916.

 

The problem however had nothing to do with the inherent strength of the sesquiplane wing spars or attachment fittings. Idflieg torsion tests on the Albatros D.5 were conducted in May of 1918 and revealed that the plywood lower wing spar could twist as much as 79 degrees without splintering. Flutter of a hinged control surface is different from the aero elastic deformation of airframe structure - the structural engineers I work with often get sloppy and use the term interchangably and I confess I made the same mistake when I summarized the article. It would be better to describe the problem as vibration.

 

The problem with the Nieuport and Albatros lower wings was that they were single spar designs, which have a natural tendency to twist around the horizontal axis that extends along the length of the spar itself. The small auxiliary strut introduced on the Albatros D.5a was an attempt to damp this twisting motion caused by inflight vibration. Unfortunately, because vibration-caused deformation was NOT understood in WW1, the auxiliary strut had no effect whatsoever. The problem was that the lower wing's center of gravity for both the Nieuport and Albatross was located aft of the spar's horizontal twist axis. In this case, aerodynamic loads interact with airframe vibrations and cause the lower wing to both twist and flex in flight - the faster the aircraft's speed, the faster the wing will twist and flex until it fails. The shot of the finite model demonstrates this fatal twist and flex that is caused by speed and vibration interacting to produce dynamic loads that no structure can withstand - the wing breaks off DOWNWARDS.

 

You mentioned that some WW1 aircraft could be dived faster than 150 mph and you are absolutely correct. All aircraft experience vibration-induced aero elastic deformation, but the twisting and flexing is generally minor thoughout the aircraft's normal speed range - the deformation only becomes a problem at speeds greater than what the aircraft usually flies. As you correctly pointed out, the drag of most WW1 aircraft prevented them from reaching this critical speed range. Most, but not all.

 

Some WW1 aircraft designs had inherent aero elastic flaws that were not apparent until the aircraft was dived at higher-than-usual speeds. This was the starting point for the generalization about 150 mph - the author stated in the article that this estimate was a ball-park guess because each aircraft would have to be extensively analyzed and modeled to determine it's unique critical speed. Because the author had done precisely that with the Albatros structure, he could accurately predict failure somewhere between 118 and 135 mph. So...my statement that all aircraft would experience these problems above 150 mph was correct, but I should have added that it is not clear HOW MUCH above that figure.

 

I am not trying to create a controversy here, and I readily admit that my summary of the article may be of no real use to you guys. I simply hoped that you would be interested in an analysis of WW1 structures by a modern aircraft engineer (the author's credentials: Staff Engineer, Lockheed Martin, 1994-1995. Structural Engineer, Space System Division, General Electric Company, 1985-1994. Structural Engineer, RCA, 1983-1985. Product Research Engineer, The Budd Company, 1978-1982).

 

Interestingly, the fix for the single spar lower wing would have been cheap and easy, had it been understood in WW1. By simply attaching a few pounds of lead weights under the leading edge, the wing's CG would have been shifted forward AHEAD of the wing's twist axis, and the problem would have been eliminated completely.

 

I love what you guys are trying to do with FMs, and I wish you guys success.

Edited February 27, 2009 by Geezer

[Heck 496]

Great posts, Geezer. Thank you. According to Peter Gray, Albatros engineers finally figured out what was causing this problem in the fall of 1917. It took them so many months because they were inspecting crashed airplanes, and it wasn't immediately obvious in a bad crash what had caused the failure. As you pointed out, the wings static tested just fine. When they did figure it out, they took two steps to cure it. First, they fitted a metal box sleeve around the first two feet of each lower wing spar where it entered the fuselage to keep that section from twisting. Second, they fitted an auxiliary strut from the interplane strut to the wing leading edge to keep the outer portion from twisting. They began, according to Gray, to apply these at the factory in the late fall and early winter of 1917. Since there were so many Albatros fighters of all marks already in service, they began to manufacture and issue kits of parts to the squadrons, so the squadrons could fix this problem in the field. The problem was, that in order to fit the metal box sleeves, the aircraft had to be dismantled and reassembled. When Albatros engineers visited the Jastas in February of 1918 to check on how this work had proceeded, they were shocked. Very few Jastas had taken the time to complete both fixes. Some had done no work at all, but most had attached only the auxiliary strut, because it didn't involve dismantling the aircraft, something the groud crews of most outnumbered and hard pressed Jastas felt they didn't have time to do. What shocked the Albatros engineers was that they felt they had come up with a cure, but wing failures were still occurring, because the Jastas had not taken the time in most cases to apply the complete fix, and quite a number had done nothing at all.

 

I think taking the tack of causing wing failures by G force is the only way to go, because TK's sim can't model torsional effects due to speed, which was the real cause of the problem. The only dive speed I've ever read by a pilot of the time was Duncan Grinell-Milne's reference to a wild dive in an SE5a, during which his speed indicator read 275mph, but Grinnell-Milne admitted that it would have been inaccurate, because it wasn't corrected, as they put it at the time, and the instrumentation of the time really wasn't that accurate, no where near as precise, or accurate as the instruments used during the Second World War. That's why you always read references in WW1 to "uncorrected barograph."

 

The information you've presented is tremendous. Thanks again. I love reading material where people appy science to the study of these WW1 aircraft, because it furthers our understanding of them. And I have a sneaking suspicion that if I asked one of the pilots at Old Rhinebeck Aerodrome if he's ever taken one of the aircraft there up to 200, or 250mph, he'd just laugh at me and say, "next question?"

[+Tailspin 3]

Thanks for that Geezer. I had already read the flutter theory on the net somehwere...lost the link...and basically agreed that was the problem IRL with the sesquiplane design. However knowing, as Peter pointed out, that flutter was not modeled in the sim I figured the only way to practically restrict diving speed in the sim was to try and add in a stress factor that caused negative consequences to the player for not adhering to some sort of speed restriction. (Seems like we both reached that conclusion, separately). Since the stress is based on G-load, that can also factor (perhaps unrealistically) into combat maneuvering. However if you can't dive over a certain speed then it follows (to me at least) that you can't perform drastic maneuvers at high speed either. What I did find was that lower threshold G-limits didn't necessarily cause damage at normal combat maneuvering speeds. They do require you to keep an eye on your airspeed indicator.

[+Tailspin 3]

Heck. You bring up a good point about the Old Rhinebeck Aerodrome planes and their pilot's flying experiences. Although they do give a fair account of basic flying, I'm sure those pilots didn't put much stress on their A/C. You don't get that from reading their accounts anyway.

[Ronbo 0]

Since dive speeds for each aircraft (VNE) are not modeled, actual combat tactics or restrictions are not possible Im finding out. when a spad 13 has a dr1 on his tail, he should be able to dive away and leave the Dr1 behind. Not so here, Ive had a Dr1 stuck to my tail and couldnt shake him until too late. the drag on the 3 wings would have kept the Dr1 up high, not sitting on my tail at at 160+mph or whatever i was doing.

 

But all in all, this is still a good dogfight simulator, and I enjoy it more as i mess with it..

[+peter01 2]

Heck. You bring up a good point about the Old Rhinebeck Aerodrome planes and their pilot's flying experiences. Although they do give a fair account of basic flying, I'm sure those pilots didn't put much stress on their A/C. You don't get that from reading their accounts anyway.

 

Yes I agree Tailspin. Probably for good reasons - regulations, and from a business perspective.

 

However, this was not always the case.

 

I have read at the Aerodrome Forum of a retired United Airlines pilot that flew a Nieuport 11 and a Spad 7. Can't remember his name, in the 1970s.

 

His show involved doing continuous barrel rolls and loops in those planes, all under 500 feet.

 

As you could imagine, the people that saw it thought it was incredible to watch.

Edited February 27, 2009 by peter01

[+Geezer 3,569]

When they did figure it out, they took two steps to cure it. First, they fitted a metal box sleeve around the first two feet of each lower wing spar where it entered the fuselage to keep that section from twisting.

 

That's fascinating stuff that I did not know about - the Albatros engineers kind of backed into a workable solution. It probably didn't "fix" the problem but delayed the onset of the torsional flutter to a speed that was higher than normally encountered in combat. The problems with installation of the field mod kits are also very interesting, and illustrate the vast gulf between guys working in an orderly factory environment, and what happens in front line units experiencing the pressures of daily operations. At work, I am one of the few guys who has actually served a hitch in aircraft maintenance so we often have heated discussions when I attempt to introduce a reality check.

 

Once again, I cheerfully admit this info may be of little use, but I am glad that you appreciate it. In the article there was also a finite model of the SPAD 7/13 wing cellule for comparison, and the SPAD's wingtips did not fail due to torsional flutter until a theoretical speed of over 300 mph. As terminal velocity of a SPAD would be less than 300 mph, the SPAD was - for all practical purposes - immune to flutter. The article also singled out the Pfalz D.3 for having similar qualities - an extremely strong aircraft that could dive at high speeds for prolonged periods of time.

 

Thanks for your comments - now it's back to the Fokker textures.

[Heck 496]

Heck. You bring up a good point about the Old Rhinebeck Aerodrome planes and their pilot's flying experiences. Although they do give a fair account of basic flying, I'm sure those pilots didn't put much stress on their A/C. You don't get that from reading their accounts anyway.

 

Back in the dark days of the Seventies, they had just completed a Camel built from Sopwith drawings that had a rebuilt Clerget 130. I believe, if I remember the pilot's name correctly, that Dick Day was flying it when I saw it. Being one of my favorite WW1 aircraft of all time, I was watching this bird every second it was in the air. Then the announcer told us that Dick was going to make a pass over the aerodrome and demonstrate the Camel's fabled right turn. Cole Palen was still running the place in those days and the announcer told us that Cole would only let Dick do one of these turns per show, because it was so dangerous that low to the ground. If Dick lost it in the turn, he would spin it into the ground and kill himself, or possibly spin it into the crowd, which wouldn't have been much of a crowd pleaser. Dick came down the length of the aerodrome and right in front of the crowd went into what seemed a seventy degree bank, they said it was about 4g, and I don't know what the actual radius was, but from the ground it looked like it was turning through ninety degrees in it's own length. The little beast whipped through that 360 degree turn in seconds, and for the first time I was seeing the Camel that I had imagined, from all those years of reading. I remember distinctly, because up to that point the Camel had disappointed me, because it really didn't fly anything like I had originally imagined it would. It was painfully slow climbing out after take off, but that was simply because it's real life climb didn't match what I imagined I would see. And traveling the length of the aerodrome it didn't seem as fast I had imagined it would be, but when it did that turn, the Camel came alive in that moment when the little beasty seemed to turn around and bite it's own tail, and I realized that I was seeing real life, not what I had imagined in all those years of reading. I will never forget that day.....

[+Tailspin 3]

That reminds me of the NASA site where they used aerodynamic data and computed things like turn rates and such. The best of them were near or slightly over 80 degrees/sec. The worst was the Fokker E at around 50/sec. Accounts of the time say the N11 could turn twice inside Fokker's turn. Perhaps an exaggeration but not too far off the mark. I don't think that data took into account things like torque effect, ect. that made the Camel turn right so quickly so a right turn at a rate higher than 80/sec. is likely.

[+peter01 2]

Attached a Se5a FM, and modified Se5a_AVIONICS file.

 

The Se5a has become one of my favourite planes, but has always been very tricky to get right. A pity, as its a very nice 3-D model and cockpit.

 

This Se5a FM is a stable gun platform, and its stable in flight without being too smooth or uninteresting. Well, thats my view. Its probably as good as I can do, and I think its very good .

 

Its a capable plane for the player and as AI. I tested this against the Alb D3 I made available in the early FM set for the Nov 2008 version - its a level or two better of course. How it fits with Thirdwires other planes from an player or AI perspective I'm not sure, but its probably okay.

 

The Se5a_AVIONICS file is included as the Aldis was not a telescopic sight, so tried to eliminate magnification. Its not spot on, but its better to my way of thinking, not so distracting. If you don't like it, just delete the file, it will revert to the stock standard settings.

 

Place the two files in your Se5a directory. Perhaps backup your current directory by a simple copy before doing so, just in case.

 

SE5a.zip

Edited March 1, 2009 by peter01