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Flight Model Verification and Data Analysis 101


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#1 J2_squid

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Posted 12 May 2010 - 18:47

Greetings Chaps and Chapeses!

As we all know there have been quite a few discussions of late about various flight models. One thread is already 14 pages long and the discussions have often been heated.

So whats Neoqb's take on it all?

As ever they are willing to listen and indeed have taken note of all that has been said. However the position (and I paraphrase) is this:-

Flight model changes will only be entertained on the basis of Numerical data. Anecdotal evidence will not cut it.

Therefore, I would invite you to do the following if you wish to have your opinion considered.

1) Provide numerical data, citing its source so it can be independently checked.

2) Present the data in a easily interpretated and clear manner. This is especially important given the international mix of the ROF community. Graphs, Charts and Tables are whats needed here. Again always cite the source for reference

3) If highlighting a issue in ROF for comparison, post either (Preferably) a track file showing the issue or at least a screen shot.


By adhereing to the above, you maximise your chances that your argument will be heard and seriously considered.

Well then, time to dust off the reference tomes, flight test data logs and slide rules! :)
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#2 Parazaine

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Posted 12 May 2010 - 19:35

There are already several posts that include 'real data'. I hope that they will be taken into account when FM's are reviewed.

http://www.hq.nasa.g...P-468/ch2-2.htm">http://www.hq.nasa.g...ffice/pao/Histo … /ch2-2.htm

http://riseofflight....erformance data">viewtopic.php?f=49&t=1319&hilit=aircraft+performance+data The First post has some interestind data AND SOURCES.

http://riseofflight....erformance data">viewtopic.php?f=49&t=2151&hilit=aircraft+performance+data
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#3 J2_squid

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Posted 12 May 2010 - 19:40

There are already several posts that include 'real data'. I hope that they will be taken into account when FM's are reviewed.

Indeed, but they are all over the show and the real data is hidden under a ton of opinion, supposition and heresay. Its often a case of cant see the wood for the trees.

The devs just dont have the time to trawl through a 19 page thread to find that one gem of useful information.
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#4 Parazaine

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Posted 12 May 2010 - 19:42

Bear with me, im trawling through the posts looking for those that present real data and providing links to them in my first post here.
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#5 J2_squid

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Posted 12 May 2010 - 19:52

Thanks parazine, thats gonna help considerably

S!
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#6 Parazaine

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Posted 12 May 2010 - 20:11

Ok, I couldnt find many but there are three there with hard data. Hope it's useful.
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#7 ImPeRaToR

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Posted 12 May 2010 - 20:50

This test shows decisively higher speeds at altitude compared to our current D.VII (and the old D.XII) despite running with the wrong fuel for altitude:
http://www.theaerodr...ted-allies.html">http://www.theaerodr...com/forum/aircr … llies.html

This post shows an attempt at deriving the true airspeed (and consequently engine power) (red graph) of the D.IIIaü engine running with the correct fuel at altitude:
http://www.theaerodr...900-post24.html">http://www.theaerodr...900-post24.html

For reference our current D.VII speeds:
Attached File  D.VII_speeds.jpg   6.89KB   4605 downloads

I hope this will allow Neoqb to estimate the appropriately corrected climb times as well.
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#8 O_Smiladon

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Posted 12 May 2010 - 21:07

S!

Hay thanks guys for your efforts in getting things right. Don’t get me wrong love the sim and the aircraft. But would be nice to know that it is as close as it could be to 100% correct in flight modeling.

Regards

RAF_Smiladon
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#9 WW1EAF_Ming

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Posted 12 May 2010 - 23:14

Almost nothing is as interesting as FM discussions for many people, I include myself in that number. Or indeed any discussion involving deep subjects like aircraft, physics, programming, virtual wind-tunnel testing and real-world simulations is fascinating

Out of interest I looked at the first report on the N28 and I see this

Included below is a summary of comparisions distilled from books that were written during or shortly after the war

A distilled summary, from books that were written. Twice-removed then from the original data

It's very difficult to find data that's over 100 years old now, but I think neoqb are interested in inspecting primary data. That would be photographs of aircraft-testing logbooks if the original data is locked away somewhere, or carefully copied records from Air Force Historians. Data which has had the greatest care taken in collecting

No worries Parazaine and I promise you mate I do not mean to be dismissive in the slightest, the first report turned out that way is all and it's late. It will be interesting to see if we can find reliable data that neoqb developers did not find. I'm 100% sure they looked, but we are many. And quite possibly Legend :)

Ming
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#10 SC/JG_Oesau

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Posted 12 May 2010 - 23:26

Good reports can be found here (you have to pay for them, and you have to cross reference where you can_) http://www.nationala...1.y=0&image1=GO">http://www.nationala...ves.gov.uk/cata … &image1=GO
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#11 Chill31

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Posted 12 May 2010 - 23:27

There are already several posts that include 'real data'. I hope that they will be taken into account when FM's are reviewed.

http://www.hq.nasa.g...P-468/ch2-2.htm">http://www.hq.nasa.g...ffice/pao/Histo … /ch2-2.htm

http://riseofflight....erformance data">viewtopic.php?f=49&t=1319&hilit=aircraft+performance+data The First post has some interestind data AND SOURCES.

http://riseofflight....erformance data">viewtopic.php?f=49&t=2151&hilit=aircraft+performance+data

I want changes as much as anyone on some of these models, but the NASA document is not real data per say. It is probably closer than any of the other data out there! but it is derived from aerodynamic formulae, not direct testing…so to say it is real as in direct testing is not 100% true.
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#12 Eldur

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Posted 13 May 2010 - 01:43

I'd like to have some clarification on the Mercedes engined planes and their performances. I wouldn't prefer Wikipedia as the best source, but lacking good books (and even those may be wrong) it's the only one I have right now, plus there are sources listed below all the articles.
There have been lots of threads concerning the performance of Mercedes engined planes and still there are some issues.

Now let's first have a look at the engine and it's different variants.
http://en.wikipedia..../Mercedes_D.III">http://en.wikipedia..../Mercedes_D.III

The original D.III was introduced in 1914, but did not see widespread use until 1916 when the fighters grew to need that level of power; earlier designs were generally powered by engines of about 110 hp. By 1917 the D.III was being widely used, most notably on the famous Albatros D.I. Production of this version was essentially wound down by May 1917, with only a handful continuing to be delivered until October. British HP ratings appear to be different than the German. It is probably that this engine would have had a slightly higher rating under British HP numbers.

This article has some very interesting statements, but first lets start with the initial D.III which had 160 hp as per German rating. The British rated it higher, but the article doesn't tell how much, so it may be 165-170 hp. It was being used mainly in the first Albatros D-Types. Production came to an end by May 1917 and just a little number had been delivered until October 1917.

Development of the basic design led to the slightly modified 170 hp D.IIIa, which took over on the production lines in June 1917. The main change was to change the piston profile to have a flat head instead of the former concave one, thereby slightly increasing maximum compression. Other changes were mainly in design details, notably a redesigned crankcase and new carburetor. Many of the accessories were also redesigned or moved around on the engine. This model was produced only briefly, for use on the Albatros D.III but there are indications that possibly some early Albatros (Alb.) made Fokker DVII's were also equipped but probably had the engines upgraded or replaced as quickly as possible. This engine has been referred to in postwar British analysis as generating 180 hp.

The D.IIIa then has been produced since June 1917, it incorporated flat piston heads instead of concave ones granting more power due to an increased maximum compression. Other changes were more concerning the overall design of the engine. The D.IIIa has only been used in a short period of time in the Albatros D.III and possibly some early Fokker D.VII that had been built at the Albatros Werke. Nevertheless the Fokkers weren't left with the D.IIIa for too long by either upgrading or replacing the engine. The D.IIIa is rated 170 hp by German numbers and 180 hp by British numbers.

A more "radical" upgrade was the 180/200 hp D.IIIaü, introduced in late 1917, the DIIIau was a standardized refinement of the DIII and DIIIa design and the u designation was never official. This engine changed the pistons again, this time to a domed profile that further increased the maximum compression – the ü was for "über", meaning "overcompressed". Additionally, a new altitude-compensating carburetor was added, which improved performance at higher altitudes. To support operations at these altitudes, water from the radiator was used to heat the air intake and prevent icing in the carburetor. The aü model (which included upgraded DIII and DIIIa blocks, was the most prolific German fighter engine of 1918 and designed into most fighter designs from late 1917 on. This included most of the entries in the First Fighter Competition at Adlershof in January 1918, notably the famed Fokker D.VII. In British post war evaluation the DIIIau actually exhibited by their standards 200hp.

Now later in 1917 the D.IIIa has been modified further, by changing the piston heads another time. Officially the model designation has not changed, but to differentiate it from the original D.IIIa, it was called D.IIIaü (it's also called "au" due to the lack of German Umlaute in the English language). This engine now had a power rating of 180 hp by German numbers and was rated 200 hp after the war by the British. Another improvement over the older variants was the new carburettor to improve high altitude performance and the use of radiator water to prevent icing at higher altitudes. So basically, apart from being more powerful in general, the D.IIIaü performs even better at high altitudes. D.III and D.IIIa engines could have been upgraded to D.IIIaü and this made it the standard fighter engine in 1918.

Confusingly, the "ü" was not an official part of the name. This leads to a number of problems in various references, which often confuse the IIIa with the IIIaü, listing the former as a 180 hp engine. It should also be noted that there are two D.IV engines, one the eight-cylinder based on the D.III pistons, and the later six-cylinder D.IVa which was essentially unrelated.

This is a very essential part of the article. The engine variants often get mixed up as there are different power ratings for each of them as well as the inofficially named D.IIIaü was still a D.IIIa by official means. So a "180 hp Mercedes" could be one of these:

- D.IIIa, British rating
- D.IIIaü, German rating

And a "D.IIIa" could be one of these:

- D.IIIa, 170 hp (180 hp by British numbers)
- D.IIIaü, 180 hp (200 hp by British numbers)

Basically, the most certain bet to get the right engine is to choose it by date. Until May 1917 it's the D.III rated 160 hp (170 hp by British numbers), used in Albatros D.I and D.II. After that it's the D.IIIa rated 170 hp (180 hp by British numbers), used in the Albatros D.III and the earliest of Fokker D.VII. Later in 1917 (not exactly specified in the article) it's the D.IIIaü rated 180 hp (200 hp by British numbers) with better high altitude performance, used in Albatros D.III, D.V(a), Fokker D.VII, Pfalz D.III(a) and Pfalz D.XII.

Now comes the hard part. Which plane when with which engine? And how should it perform?

1. Albatros D.II
Engine clearly D.III (160/170 hp)
Top speed given at the RoF site is 164 km/h, while Wiki says 175.

2. Albatros D.III
Engine mainly D.IIIa (170/180 hp), but there might have been a later series with D.IIIaü (180/200 hp) as it has been produced until December 1917. Most probably Daimler changed production from D.IIIa to D.IIIaü earlier. Some more exact dates would help a lot here.
Top speed given at the RoF site is 170 km/h, Wiki says it's 175 with 170 hp D.IIIa.

3. Albatros D.Va
Engine clearly D.IIIaü (180/200hp) as it has first been produced in April 1917. Here the Wiki article says it still used the D.IIIa which can't be right as Daimler switched to producing D.IIIaü only at least 4 months before Albatros started producing the D.V. But do not forget the fact that the D.IIIaü was officially still named D.IIIa which may lead to wrong hp numbers.
Top speed given at the RoF site is 170 km/h (and I really wonder why, it had been 186 for a very long time, but the plane never was that fast in RoF), Wiki says it's 187 with 180 hp D.IIIaü.

4. Fokker D.VII
Engine clearly D.IIIaü (180/200hp), but still would be correct to have an early D.VII with D.IIIa (170/180 hp). Wiki mentions the use of it in the first D.VII.

The very first production D.VIIs were equipped with 170-180 hp Mercedes D.IIIa engines. Production quickly switched to the intended standard engine, the higher-compression 134 kW (180-200 hp) Mercedes D.IIIaü. It appears that some of the early production D.VIIs delivered with the D.IIIa were later re-engined with the D.IIIaü.

Top speed given at the RoF site is 190 km/h, Wiki says it's 186 with 180 hp "D.IIIa" (which either may be the D.IIIa by British rating or the D.IIIaü by German rating! Primary sources need to be checked here)

5. Pfalz D.IIIa
Pfalz D.III would have the D.III (160/170 hp) engine, as it has been produced from April 1917 on which changed to Pfalz D.IIIa in November 1917 where the Merceded production was most probably completely switched to the D.IIIaü (180/200 hp) engine. So this is the correct one.
Top speed given at the RoF site is 168 km/h, Wiki says it's 185; interestingly, the German Wiki article says 169 for the D.III (160/170 hp) engined Pfalz D.III and 181 for the D.IIIa with "180 hp D.IIIa" which is indeed the D.IIIaü.

6. Pfalz D.XII
The first prototype flew in March 1918, so it's clearly the D.IIIaü (180/200 hp).
The RoF site still says it has the "D.IIIa" (which changed in 1.012), and it gives a top speed of 189 km/h. Wiki says it's just 170 while the German article says it's 180.

Now let's sum it up:

1. Albatros D.IIs may be too slow (they seem aerodynamically worse than D.III + less power = Wiki figure might be wrong or the D.III speed is too low over there)
2. Albatros D.III is a tad too slow
3. Maybe a late Albatros D.III with D.IIIaü engine should be introduced (only with better sources confirming there were such)
4. Albatros D.Va is definately too slow, most probably because it doesn't have the D.IIIaü modelled
5. Fokker D.VII seems to be OK, better sources needed
6. Pfalz D.IIIa is definately too slow, as it most probably has the performance of an earlier Pfalz D.III with 160/170 hp D.III engine
7. Pfalz D.XII should definately be re-introduced with it's correct engine, the D.IIIaü ( 180/200 hp).
8. The Pfalz D.XII we have now should stay as "Pfalz D.XIIF" or "Pfalz D.XII (BMW)", just in case it might have had some front service (at least the Anthony Fokker source telling of the removal of BMW engines from Pfalz D.XIIs to hang them into Fokker D.VIIs approves it's existence).
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#13 sundemon56

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Posted 13 May 2010 - 02:29

Great job, Eldur, putting it all together, there's just one thing I'd like to mention: Neoqb's version of D7 is late production, earlier production types would've had different engine panels

Attached Files


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#14 =Fifi=

=Fifi=
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Posted 13 May 2010 - 02:51

1. Albatros D.IIs may be too slow (they seem aerodynamically worse than D.III + less power = Wiki figure might be wrong or the D.III speed is too low over there)
2. Albatros D.III is a tad too slow
3. Maybe a late Albatros D.III with D.IIIaü engine should be introduced (only with better sources confirming there were such)
4. Albatros D.Va is definately too slow, most probably because it doesn't have the D.IIIaü modelled
5. Fokker D.VII seems to be OK, better sources needed
6. Pfalz D.IIIa is definately too slow, as it most probably has the performance of an earlier Pfalz D.III with 160/170 hp D.III engine
7. Pfalz D.XII should definately be re-introduced with it's correct engine, the D.IIIaü ( 180/200 hp).
8. The Pfalz D.XII we have now should stay as "Pfalz D.XIIF" or "Pfalz D.XII (BMW)", just in case it might have had some front service (at least the Anthony Fokker source telling of the removal of BMW engines from Pfalz D.XIIs to hang them into Fokker D.VIIs approves it's existence).

Well, in fact for you almost all germans planes are too slow… :?
So i'm expecting to be outrunned by Pfalz and Albys soon or later in my Spad…cause it's already pretty hard to get them off our six, full throttle :roll:
Hmmmm…
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#15 WW1EAF_Ming

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Posted 13 May 2010 - 09:32

On interpretation of data and the meta-analysis

In 2001 two Danish medical researchers Asbjorn Hróbjartsson and Peter Gøtzsche became suspicious about the quoted '35% of patients' who would get better if told a dummy treatment they had been given was real. This 35% at that time was quoted everywhere they looked, in textbooks and journal papers, magazine articles

Eventually they tracked down the source of the statistic: Henry Knowles Beecher, 'The Powerful Placebo' 1955

It wasn't enough to convince Hróbjartsson and Gøtzsche so they carried out a meta-analysis on Beecher's data. This is what scientists do when they are faced with a long series of conflicting answers to a question: essentially it is a formalised way of analysing all previous attempts to answer the question. They examined the quality of each [dataset]: its experimental methods, its biases, its statistical analyses. The idea is to get a flavour of each set of results and then put them together in a way that reflects how much weight should be given to their stated results [Ming's emphasis] In the end, such a study makes some pronouncement about the overall weight of evidence for and against a hypothesis[/size]

Reference: 'Thirteen Things That Don't Make Sense' Michael Brooks, 2010: page 170

The study was over 7,500 patients

All data of every type can be useful to help prove or disprove a hypothesis. But some data can be seen to be more important than other data, more weight can be given to some conclusions

That's what we have in our flight-models case. We have masses of data but not much data as source material. We can sift through all the data and give more weight to data that's returned from primary sources


On the placebo effect btw interested reader, the reason for the meta-analysis above, the conclusion of the study was 'Over this wide spectrum of [medical] complaints, they found no evidence that placebo treatments had significant effects on health'

In 2003 the researchers re-visited the study, this time over 11,737 patients and their results were the same. 'Most patients are polite and prone to please the investigators by reporting improvement even when no improvement was felt… we suspect biased reporting occurred'

Ming
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#16 Eldur

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Posted 13 May 2010 - 10:09

Well, in fact for you almost all germans planes are too slow… :?
So i'm expecting to be outrunned by Pfalz and Albys soon or later in my Spad…cause it's already pretty hard to get them off our six, full throttle :roll:
Hmmmm…

Of course not… it's just that my post is about the Mercedes engine confusion that often leads to wrong data. There are lots of other issues like N.28 bad sustained turning ability, Dolphin too slow, Dr.I too fast at high altitudes, just to name some of the most obvious. These all should be fixed. And an Albatros D.Va will never outrun any SPAD, because it would still be a lot slower.
I'd also like to see some more Entente planes to fill up some gaps… S.VII, Sopwith Pup and Triplane and even the Snipe. I don't bother about 3km/h more or less, but having a top speed of 160 where it should be 186 is just way off. Same for the Dolphin… it's almost 15mph below it's specs.
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#17 WW1EAF_Ming

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Posted 13 May 2010 - 10:51

Parallel thread, I am Mington the truffle-hound :)

http://www.theaerodr...man-planes.html">http://www.theaerodr...com/forum/aircr … lanes.html

Ming
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#18 Vati

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Posted 13 May 2010 - 11:02

Parallel thread, I am Mington the truffle-hound :)

http://www.theaerodr...man-planes.html">http://www.theaerodr...com/forum/aircr … lanes.html

Ming
Lol, Hohun… please, for the sake of sanity, be careful with his 'calculations'. When I followed him on other sims, his 'proofs' were a mess. There is nothing more dangerous than a man with formulas which he does not understand :)
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#19 ImPeRaToR

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Posted 13 May 2010 - 16:53

Parallel thread, I am Mington the truffle-hound :)

http://www.theaerodr...man-planes.html">http://www.theaerodr...com/forum/aircr … lanes.html

Ming

You could have waited for some results before you revealed our secret inquiries :P


Anyway Eldur, I think you have to be careful with the speeds given on wikipedia since they might be TAS and the altitude is not always given so you have to take them with a sack of salt. The list of engines is pretty good otherwise I believe, although there may have been a few "subversion" in between, I was hoping somebody else would step in and explain it, your time line might be a bit off though:
Some of the Pfalz D.IIIa and D.Va might have received the D.IIIaü at the end of their production, they definitely received replacement parts and engines upgraded to the new standards. However the Pfalzes might not have received many of them since they were removed from active service a lot sooner than the D.Va. This could of course have other reasons as well though.
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#20 HotTom

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Posted 13 May 2010 - 17:03

Thanks for the link, Ming.

Excellent discussion!

HT
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#21 ImPeRaToR

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Posted 13 May 2010 - 17:30

The Pfalz D.IIIa is definitely too slow btw ;) The climb rate fits the D.IIIa I believe but the top speed is more like that of the Pfalz D.III. Hopefully it will be made somewaht harder to fly before it gets a higher speed.
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#22 J2_squid

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Posted 13 May 2010 - 17:32

The Pfalz D.IIIa is definitely too slow btw ;) The climb rate fits the D.IIIa I believe but the top speed is more like that of the Pfalz D.III. Hopefully it will be made somewaht harder to fly before it gets a higher speed.

Prove it Imp ;)
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#23 Chill31

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Posted 13 May 2010 - 17:46

It would take some research, but I think if NEOQB was interested, there are enough people with WWI airplanes that would be able to do direct testing. Granted most are reproductions, but even that data is better than "i think" or "I believe" data that people often show around here.

It is probably more difficult to get than simply reading a thousand books by joe schmo who made estimates of estimates…but I will see if I can get some data from a few people or at least find out what it would take to get them interested in providing data…

In the US alone, i think there is at least one flying reproduction of all aircraft currently in RoF….
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#24 J2_squid

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Posted 13 May 2010 - 17:53

Be careful though Chill, a repoduction with a modern engine (even one designed to be close to the original) is going to be quite different from the original.

Mikeal Carlsons DR1 actually has a Le Rhone engine, on his website he lists the cruise speed (whatever that is) of it as 160 Kph. http://www.aerodrome...&id=10&Itemid=8">http://www.aerodrome...index.php?optio … 0&Itemid=8
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#25 Chill31

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Posted 13 May 2010 - 17:54

Squid, I imageine 160 is correct for the cruise speed of the Dr1….thats about 100mph.

I would say that any direct testing with a close engine approximation is better than anyones "best guess" on this forum

**He is running a 110 Le Rhone!! why would you doubt his cruise speed? (that is if you were doubting) I would take that as gospel…160 in cruise for the DR1…it would be worth asking him (with NEOQB backing or directly asking) for more data
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#26 ImPeRaToR

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Posted 13 May 2010 - 18:00

The Pfalz D.IIIa is definitely too slow btw ;) The climb rate fits the D.IIIa I believe but the top speed is more like that of the Pfalz D.III. Hopefully it will be made somewaht harder to fly before it gets a higher speed.

Prove it Imp ;)


Eldur listed a ton of claims without posting proof… I was just adjusting them.
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#27 J2_squid

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Posted 13 May 2010 - 18:03

I would say that any direct testing with a close engine approximation is better than anyones "best guess" on this forum

**He is running a 110 Le Rhone!! why would you doubt his cruise speed? (that is if you were doubting) I would take that as gospel…160 in cruise for the DR1

Well define cruise speed. I wouldnt of thought is the same as full out top speed. Also cruise speed at what altitude? It looks like a good ballpark figure, but we have to also figure which ballpark it refers to.

Would love to hear Mikaels take on all this though.
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#28 Chill31

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Posted 13 May 2010 - 18:05

Agreed. It needs to be quantified…but i think you and I are on the same page as far as noting that there are people out there with THE airplanes who can provide THE data that simulator programmers would be interested in…
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#29 WW1EAF_Ming

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Posted 13 May 2010 - 18:12

I've no idea how practical that is Chill, but it's a very good idea

cruise speed

Hmm :)

Ok who's going to ask Mikeal Carlson if he can run some tests for us

I'm serious, he may even discover Rise of Flight is interesting. I'm not assuming that he knows about Rise of Flight and summer's on the way

I'll truffle him out and drop him a line in a day or two if no one knows how to contact him

Hang on I shouldn't be lazy, I'll do some legwork…

My email client isn't set up to directly send him an email from this page, can someone please dig out his email address for me? and I'll contact him on behalf of neoqb forums members

http://www.aerodrome...id=16&Itemid=13">http://www.aerodrome...index.php?optio … &Itemid=13

Our European Air Force C/O is in Sweden. With a stopwatch if I have my way :)

Replica Pfalz D.IIIa must be another story she's not the prettiest. Sorry old girl :)

Ming
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#30 J2_squid

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Posted 13 May 2010 - 18:13

Agreed. It needs to be quantified…but i think you and I are on the same page as far as noting that there are people out there with THE airplanes who can provide THE data that simulator programmers would be interested in…

Totally, I think Womenfly2 tried to contact Carlson a while back but didnt get very far. Couldnt hurt to try again.

mikael@aerodrome.se <mikael@aerodrome.se> thats his address Ming :)
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#31 ImPeRaToR

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Posted 13 May 2010 - 18:15

Looking at my copy of Peter L Gray's "The Pfalz D.III" (Profile Publications no.43), 1965:

British figures from a captured D.III (160 hp Mercedes)

Max. speed at 10,000 ft. 102.5 mph, at 15,000 ft. 91.5 mph. Climb to 5000 ft in 6 min., to 15,000 ft in 41 min. 20 sec.

German figures (not sourced)

Max. speed 165 km. hr. (103.12 mph). Climb to 1,000 m. (3,280 ft.) in 3.25 min., to 2,000 m (6,560 ft) in 7.25 min., to 3,000 m (9,840 ft.) in 11.75 min.

http://www.theaerodr...8421-post4.html">http://www.theaerodr...8421-post4.html

As you can see, the performance of our D.IIIa seems to be modelled after the D.III which had a weaker engine. Climb times for the two tests are roughly matching, british max speed is TAS, german speed IAS at sea level.
D.IIIa (175/180 hp Mercedes): at a loaded weight of 911 kg. (2,004 lb) made test climb to 5,000 m (16,400 ft.) in 33 min. on 4th Feb. 1918.

Ours takes 28mins. looks like the engine curve is a bit weird I guess. Seems to have level speed of the D.III and climb performance of D.IIIa.
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#32 J2_squid

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Posted 13 May 2010 - 18:18

Quote:
Looking at my copy of Peter L Gray's "The Pfalz D.III" (Profile Publications no.43), 1965:

British figures from a captured D.III (160 hp Mercedes)

Max. speed at 10,000 ft. 102.5 mph, at 15,000 ft. 91.5 mph. Climb to 5000 ft in 6 min., to 15,000 ft in 41 min. 20 sec.

German figures (not sourced)

Max. speed 165 km. hr. (103.12 mph). Climb to 1,000 m. (3,280 ft.) in 3.25 min., to 2,000 m (6,560 ft) in 7.25 min., to 3,000 m (9,840 ft.) in 11.75 min.


http://www.theaerodr...8421-post4.html">http://www.theaerodr...8421-post4.html

As you can see, the performance of our D.IIIa seems to be modelled after the D.III which had a weaker engine. Climb times for the two tests are roughly matching, british max speed is TAS, german speed IAS at sea level.
Quote:
D.IIIa (175/180 hp Mercedes): at a loaded weight of 911 kg. (2,004 lb) made test climb to 5,000 m (16,400 ft.) in 33 min. on 4th Feb. 1918.


Ours takes 38mins.

Nice one :)
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#33 ImPeRaToR

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Posted 13 May 2010 - 18:19

I was mistaken about the climb time of our D.IIIa to 5km so I edited my post accordingly. Now we need to find the level speed of the D.IIIa ;)


Hmpf, this makes no sense. If the governing factor is HP/weight and the HP rose the speed must have increased, especially since the weight did not change. All I can find says more less that the speed of D.III, Albatros and D.IIIa was about the same. Then again, these planes could all have been equipped with D.IIIa or D.IIIaü engines by 1918.


Can't think of anything else at the moment, but themaximum speed of the D.IIIa was 112 mph at sa level - not terribly impressive, but better then the 102.5 mph generally attributed. (As shown in your post, this lower figure was at 10,000 feet)

That sounds more like it, 180km/h, close enough to the D.VII that currently has a D.IIIa engine. Both Albatros D.III and D.Va do not have the speed of the D.IIIa engine either but they don't have to if they are portraying early production planes while the Pfalz D.IIIa always had this engine.
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#34 Chill31

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  • Posts: 1891

Posted 13 May 2010 - 18:28

I would let NEOQB act or direct your actions on contacting someone for them…

Its different if youre an individual asking rather than a company asking. Some people are nice and helpful regardless, and some people dont respect the little man…

Just me, I'd let NEOQB drive the show on this. There should be a test profile for items of interest and unless you know how they are computing the aerodynamics for RoF, you probably wont know the exact info they need…
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#35 WW1EAF_Ming

WW1EAF_Ming
  • Posts: 2565

Posted 13 May 2010 - 18:29

Cool thanks squid

Here's my action-this-day email on our group's behalf to Mikael

Hi Mikael summer is on the way :) and I am wondering sir

Do you have flight-test records of your Dr.1 that you can make available to me and my friends at the Rise of Flight forums please?

We are discussing your aircraft there and thinking that maybe our group of WW1 aircraft fans can help neoqb find useful information that will clarify (for them and for neoqb forum members) how accurate their wonderful flight-sim is compared to your even-more-wonderful Dr.1

We're discussing our WW1 planeset here-

http://riseofflight....php?f=49&t=9812">viewtopic.php?f=49&t=9812

The C/O of the European Air Force (virtual squadron, online) is in Sweden with a carrier pigeon on standby :)

Thanks Mikael and best regards,

Peter (EAF19_Ming)

Ming
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#36 WW1EAF_Ming

WW1EAF_Ming
  • Posts: 2565

Posted 13 May 2010 - 18:31

I would let NEOQB act or direct your actions

How's that ^ :)

Ming
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#37 BroadSide

BroadSide
  • Posts: 2057

Posted 13 May 2010 - 18:31

This site has quite a bit of data. Someone looking for data on a specific engine/plane might find it here:

http://www.crossandc...e.com/index.asp">http://www.crossandc...e.com/index.asp

and their link page also has some great sites:

http://www.crossandc....asp?Display=23">http://www.crossandc....asp?Display=23


I think this is a great idea, one thread to post data, so that we can get to the core of some of these issues and see some adjustments where needed.

Sure would like to see the SE5a have a tougher engine….just gotta find the data that supports that.
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#38 J2_squid

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Posted 13 May 2010 - 18:32

Top Bananna! :D
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#39 Chill31

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Posted 13 May 2010 - 18:32

Sounds nice Ming, I hope he is receptive!
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#40 WW1EAF_Ming

WW1EAF_Ming
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Posted 13 May 2010 - 18:38

What I should tell you Chill and what you might not know because they have been too busy to talk to us much since last year- neoqb are a special team.

They will be very interested to hear any primary information, even from a replica plane. The number-crunching is something that neoqb is very good at, that's obvious. But any and all information is useful when given its correct weight. Mikael's plane is not flying in WW1 but it's an accurate model I should think and seeing comparative flight-test data in itself will be very interesting

Ming
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