The problem is that power varies with altitude and hence the speed and angle of bank for the best turn varies as well. You assume given speed and angle of bank which is not correct for this case.

Anyhow, incompressible flow theory may have been used by RAE or whoever - what is important for our game is what is the most close to reality.

Crumpp: Posting the NAVWEPS chart and showing the relationship between 21 s, 68 deg bank angle and the 115.6KEAS*1.37 shows you have no idea about what you are doing: That chart just shows the relationship between these variables in a stationary turn.

You use the unsupported preconception that the Spitfire can hold a sustained turn bank angle of 68 deg at 20,000 ft and this is where you go wrong. The RAE report R&M 2349 by Morgan & Morris actually states the bank angle for the Spitfire at 20,000 ft which is 51 degress, not the 68 degrees you pulled out of a hat. Now instead enter the RAE turn speed of 141 mph TAS and bank angle of 51 deg in that same chart. This gives us 11.4 deg/s. This is equivalent to a turn time of 31.5, not 21 s. You see now?

In addition, I really like the circular argument you use to MIG-3U's question about the impact of power: First you assert that the Spitfire will have a turn time of 21 s at 20,000 ft without any power analysis whatsoever, period. Now you suddenly claim it's dependant on which Merlin version was used, compressibility corrections etc. Are you perhaps beginning to feel the heat and want back away from the 21 s claim?

Which brings us to the question of proof: I don't think you understand how this works: You have made a claim that the Spitfire turn time at 20,000 ft is 21 s. If you want to convince us then YOU need to provide proof of this either through references or calculations showing where the RAE who claim 31.5 s got this wrong. I wish you good luck with that.

Personally, I'm comfortable with my simulation result of 31.65 s and seeing that this is in line with the Royal Aircraft Establishment result I'm placing my money on Mr Morgan & Morris and their figure of 31.5 s and I will not hold my breath until I see your "proof" for the 21 s claim.

I can add that the C++ code which validity you question (and that I use to come to the same conclusion about the Spitfire turn performance at 20,000 ft as Mr Morgan & Morris of the RAE) is an extension of the code I wrote for my Masters Thesis which was analysis of fighter jet performance and the influence of external stores on speed, climb and turn rate performance etc. This is actually a bit more complicated than analysing the Spitfire by the way since the external stores really mess up the area ruling and leads to complications, especially in the transonic range. However, seeing you are an expert in everything from 100 octane usage during BoB to turn rates I guess this falls far below the level of your extensive expertize.

I also notice that you are now "employed full time in aviation as a pilot" which was interesting to learn because previously, while you have generously shared your experiences and anecdotes of a life as a private pilot, posted pictures of small privare aircraft that you own etc., you have made no earlier mention of this that I recall. Would be interesting to hear which type of aircraft you fly on a commercial basis? Do you fly passenger or cargo services?

While you were quick to question my formal education, I notice that you have still not replied regarding your own credentials. When you do, In addition to the info about when you got your Msc and your experience in the aeronautical industry please add some info about what you did for your Masters Thesis. Based on your penchant and reliance on charts like the NAVWEPS, was it something to do with nomograms perhaps? :grin:

So what's your point?

Brag about some C++ analysis of yours of which nobody gives a flying frak...?
Generic harassment of Crumpp because a long time ago he dared to disagree with your opinion?
Assuming a hypothetical identity on the internet as an engineer who have been supposedly intimately involved with the design of Gripen?

This sounds like just a perfectly ordinary internet troll to me.

And again an interesting topic wasted on mutual personal disputes. Why not use the extraordinary pn system to settle your issues with certain people and leave the discussion to those who are genuinely interested in the topic?

Because the personal dispute is originated in one party's personal frustration and an acute desire for attention and approval.

The RAE's use of a single chart given the absence of any differientiation between power levels makes perfect sense with the Merlin XX predictions.

The Merlin XX was predicted to maintain similar power from sea level to 20,000 feet.

1020 Hp at Sea Level and 1075HP at 20000 feet:

http://www.enginehistory.org/members...a/Table-04.jpg

http://www.enginehistory.org/members...lysisR-R.shtml

Troll huh?

I think that criteria fits better on you yourself than anyone else here:

First of all both you posts are totally devoid of any content other than personal attacks. Secondly, you twist words: I have said I have worked on the Gripen, you inserted the word "intimately" to make it seem like I said something else.

And secondly, I'm not assuming any engineering identity or bragging: I responded to a claim by your 100 octane wingman that I "lacked formal education".

I like the psycological assessement in your last post BTW,"is originated in one party's personal frustration and an acute desire for attention and approval"

Talk about pot calling kettle black.......

What Kurfurst neglects to mention is that he holds a grudge since I after several fruitless attempts to him personally was forced to contacted his ISP provider to remove my research material which he without my permission had marked with his own watermark and published on his site.

Now if you have anything constructive to contribute to the issue of 21 versus 31 s turn time for the Spitfire at 20,000ft then add that otherwize you can just bug off and leave the discussion to the grownups.

So how does the Merlin XX data you posted above support your 21 s claim?

The Merlin XX is what the RAE refer to in their report R&M 2349 as well. So you both use the same engine data but come to different conclusions.

Why do you agree on the low level results but come to different conclusions for 20,000 ft performance?

Remember the RAE result is that the Spitfire will sustain a loadfactor of n=1.57 (bank angle 51 degress) and turn time 31s at 20,000ft. You get sustainable loadfactor n=2.70 (bank angle 68 degress) and turn time 21s at 20,000ft. Both results refer to the same engine so please explain.

BTW: I note that while you are quick to question other peoples competence and credentials you have not provided anything of substance yourself to back up your claims and it's faily obvious you have nothing to show so I wont press you any more on that.

Let's see your diploma then.

I don't neglect anything at all, you don't own anything of that paper, and I simply get a feeling of puke when I see posts motivated by your most primitive feelings, the very grudge you wish to attribute to me and your perceivable frustration with life. Grudge can only exist between equals, and so in your case, its despise what I feel.

The papers you have mentioned belong to Stockholm Technical School and you have made unauthorized copies of them from without permission, as you have made it clear in your e-mails (and the fact that later despite numerous request, you refused to name the source), which holds them in their collection. You had become very nervous when I suggested to inquire the place about your activities there and your claim of copyright.

Of your character, it tells me a lot that well until that, you were busy kissing my underside in hope that I'd buy it and fetch some bones for your from my collection. We have traded a few items, and thankfully that's where our contact ended before I would begin to feel filthy.

When that cooperation ended, and your ego was hurt by my posts pointing out your immoral behaviour, you have reacted in the exact manner any dishonest freak would do: attempts at slander at various boards, about your allaged rights to certain papers you took photos off without the permission of their holding archieves.

You have tried to sell that story at various respected aviation communities, at allaboutwarfare.com etc. and other serious aviation sites/forums, where people quickly realized who you are and laughed, in distaste. You then disappeared from all these places, having successfully destroyed your own credibility once and for all. I think the most civilized comment you have received was that your behaviour reveals 'seriously bad taste'.

Your pitiful motive was that I stood up against your constant underhand attack on Crumpp, similar to that behaviour you display here. Your post history reveals that you have only registered here to 'get back' at Crumpp for the humiliating education you have received at his hands previously.

You see, that's exactly what motivates you, an overblown ego of the usual internet troll/nerd, wrapped in pompous sentences, and a made up identity.

Or else what happens you big big grown-up?

I just remembered this:

http://www.youtube.com/watch?v=TFl8X4y9-94

I think this "G" is in fact a Buchon.

1. The Merlin XX had a two speed supercharger. The first page you refer gives power at high altitude gear at sealevel due to analysis. See the appendix A at bottom of the second page for power at low altitude gear at sealevel.

2. Even at constant KEAS speed and constant power, the resulting force, thrust, decreases when the altitude increases because force is power divided with true speed. To maintain given angle of bank at given KEAS, power must increase with altitude.

IvanK,
Could you please post parts of the report on turning performance at 20k?

TIA

This is I think the only relevant bit that includes Sustained turn boundaries for 20,000',25,000',30,000', and 35,000'. "Angle of straight Climb" is Ps=0

http://i40.photobucket.com/albums/e2...pitturn20K.jpg
http://i40.photobucket.com/albums/e215/zulu64/condA.jpg

Thanks IvanK,

So power is higher, 1100hp at 20k, than 1050hp at 12k. Time to turn 360deg is about 30s at 20k, while it was 18.6s at 12k.

This video which claims to "proof" that the 109 was equivalent in turn to the spit is pretty much useless. The first interviewed guy never flew a spit as he admitted himself. The second guy we don't learn about his flight experiences. We therefore just learn that the 109 was a good turner (perhaps better than ingame but that's another discussion) and better turner than the P51. Now that is nothing new at all.

Fun to watch but not even anecdotical evidence on how close the Spit and the 109 were.

It's a bit offtopic, but I never quite understood this 'Buchon' thing. Sure the Buchon handles slightly differently (from what I gather, directional stability was worse than on the 109, which already exhibited low directional stability characteristics), but in essence it was just a German built G-series airframe, with a very similar Merlin/HS engine wrapped onto it.

A Merlin installation v a DB605 installation is significantly different though.

Though I havent seen any Specfic excess power differences between the two I am sure they would be significant thus affecting sustained turn and climb performance. My Gut feeling is the DB605 variant would be the lesser performing aeroplane.

The additional data posted by IvanK now gives the engine power as well and the turn time at 20,000 ft can as MIG-3U points out be read out of that figure to be in then order of 30 s. In fact the same report contains an even more precise figure of radius 1045 ft, bank angle 51 degrees and turn time 31.5 s in table 4 on page 4.

While we are waiting for Crummps 21 s 68 degree bank proof here are some C++ simulation results showing the relative performance between the 1.3 ata Me109E and Spitfire Mk1 at +6.25 boost:

As expected the Spitfire is somewhat better at 20,000 ft due to the lower wing loading. However, the interesting thing is however that at low level (1 km) my simulations show that while the Spitfire turn better at low speeds, the Me109E turns better than the +6.25 boost Spitfire Mk1 at TAS speeds over 290 Km/h. However, if one assumes the +12 boost then it is of course no contest, either at low or higher speeds.

Hello Holtz,

Do you consider 109 slats in your simulation?

Yes, slats are in there implicitly but not modelled as such: I assume a power off low Mach Clmax of 1.45 and since the slats on the Me109 start to come out at around Cl=0.8 and IIRC are fully deployed at 1.2 they can be said to be modelled.

I know this very well MIG3.

If you look at the thread before my altitude conversion there is only one document from this report posted.

Page 16 is when IvanK posted one snippet from the report:
http://forum.1cpublishing.eu/showthr...=32285&page=16
Page 17 is when I showed Kurfurst how to convert performance to altitude from that snippet:
http://forum.1cpublishing.eu/showthr...=32285&page=17

Here it is the only information in the thread at the time I replied:

http://img823.imageshack.us/img823/3811/turnwitflap.jpg

There is not enough information to do any kind of detailed analysis.

None the less, I knew Holtzauge would be up to his old tricks again as soon as he posted. So I included the answer to specific performance in my very next reply.

http://forum.1cpublishing.eu/showpos...&postcount=170

But Mr Holtzauge ie Msc Aeroengineering blah blah blah did not understand.

There is no power information provided and the report is obviously discussing theory and not reality with the different degrees of flap. So when I answered Kurfurst question about how to change altitudes, there was nothing to convert in terms of power to get specific performance.

Holtzauge is not some engineer. He is an internet troll plain and simple.

Why do I know this?

I rather long history of dealing with him. Let's look at how to vary thrust production with altitude. This is from the old Ubizoo board. The discussion comes about because some folks cannot seem to line up power in terms of Equivalent Airspeed. They kept coming up with a load factor that was way too high when they used EAS. Why? They knew how to parrot some TAS formulation but did not understand the theory behind it. Therefore when they went to convert EAS back to TAS, they did not convert their power and ended up with much higher load factors.

A basic aircraft performance text, Perkins and Hage, "Aircraft Performance, Stability, and Control:
http://img10.imageshack.us/img10/708...epowerwith.png

http://forums.ubi.com/showthread.php...=1#post2939042

Holtzauge says:

http://forums.ubi.com/showthread.php...=1#post3177597

That is why I ignore the guy.

:cool:

Maybe this is one the lesson in aerodynamics at the IL-2 General Discussion Forum that Kurfurst was refering to earlier? The problem with that lesson was that you did not only loose me but also Wurkeri, JtD and FatCat_99 who did not understand that lecture either.

http://forums.ubi.com/showthread.php...soviet+fw-190a

One thing that escapes me is where you have hidden the proof for the 21 s turn time for the Spitfire Mk1 at 20,000 ft you claim? I can't see the forest for all the trees.

Can you point that passage out please?

Also: I notice you are back to calling me a troll and no engineer and claiming I have no Msc degree. The irrefutable proof for this seems to be that I don't agree with you right? Where is your resume?

How about staying on topic and nailing down the 21 s turn time proof instead?