bongodriver

No, the MkXVI was a MkIX airframe in every way, the MKXIV that we are actually talking about is a Grifon Spitfire and has the larger tailplane accordingly, the point stands that CG limitations for that type are unchanged from wartime specifications. it's odd how you have misquoted me in that post.

I selectively read the relevant information, I certainly do not miss or try not to miss the important details. clearly the limits on a MkV were not the same as a MkIX as we have all seen a MkIX type certificate showing aft limits of 10.5" and 12.5" This is your claim on MkIX CG limitations from post No5 Yet we see modern day MkIX's with CG at 7.0" and this is the most limiting, you also seem to be confusing MkIX's with MkV's again as there has been no NACA report on a MkIX shown. Yes, I did misread the magnitude of adjustment, the important piece of information to take away from this is that the longitudinal instability was 'eliminated' with a minor adjustment of rearward CG, this completely flies in the face of your inherently unstable in normal CG ranges theory. No, there are no post war modifications, there are in service modifications which you have even included in your opening post that increase the stability margin and then in another post completely denied it and subsequently changed your mind again, not that you are backpeddaling to suit your agenda of course. it tells us plenty, it tell us that the elevator had no modifications, it tells us the aircraft is very close to full authentic wartime spec, it tell us that CG was unrestricted to any arbitrary civilian limitations I have read the certificate, that is how I know it says nothing about a wartime limit of 9.0" and the actual rearward limit of 7.9" is bang on the money for a standard elevator with no inertia weight and a DeHavilland prop, standard elevator being the mass balanced and not aerodynamically horn balanced one. As we can see G-AIST has the early type standard elevators and not the horn balanced late revision (you know, the same one on the MkIX that would have increased its CG to 9.0") Yes, yes it does, a wartime modified elevator that increased the stability margin. Is off topic and irrelevant to the Spitfire Mk IX. This one baffles me, you quoted yourself and declared it irrelevant, and the quote is not even something you actually wrote, I am in complete agreement of course but it is curious, it does lead us nicely in to the prolonged agony that is waiting for you to actually provide the data on an actual MkIX you claim to have. I didn't, I posted MkXIV data to illustrate further to you that wartime limitations are not restricted in civilian operations, I have posted data for most relevant marks highlighting this point that you so vehemently deny. A modification was tested yes, no modification was implemented, to date elevators remain to original wartime specification. Oh but I do, you only have to look and see it is the late wartime aerodynamically horn balanced elevator. Well we can clearly see now that you are incorrect on this, we even have videos of modern day pilots describing the mild effects of instability in an aircraft permitted to carry fare paying members of the public, I understand it is tough for you to let go of this fantasy of yours. I have produced several type certificates that detail precisely the configuration of the aircraft in question, there are no unknown modifications on the example in question, there is a full list of modifications and none involve post war revisions of the elevator design, half a rear tank is representative of a wartime aircraft with half a rear fuel load, you know, the configuration that combat was permitted. http://www.caa.co.uk/AANDocs/17661/17661040100.pdf What we must take away from all this research in to the modern day MkIX is that the CG range varies dependent on configuration, aircraft that carry more weight in the rear actually have less restricted CG rear limints, single seaters without rear tanks and standard elevators limited to the 7.0 to 7.2 range. http://www.caa.co.uk/AANDocs/22416/22416020000.pdf a single seater with no rear tank and no post war modifications of elevators with a 9.5 rear limit http://www.caa.co.uk/AANDocs/26450/26450020000.pdf and dual seaters getting up to the 8.0 range http://www.caa.co.uk/AANDocs/19022/19022000100.pdf http://www.caa.co.uk/AANDocs/20929/20929000000.pdf and a single seater with rear tanks and standard elevators reaching 12.5" aft of datum http://www.caa.co.uk/AANDocs/17661/17661040100.pdf on investigation including other marks it does show an inherent limit in the Spitfire design where instability begins to manifest, this instability is at worst mild when the limit is slightly exceeded, the limit in this case seems to be approx. the 7.0" aft CG, most of these reports show that a 7.0" aft CG is a range that is very easily kept within for a standard loaded Spitfire (equivalent to full fighter loads) with single occupant and no rear fuel, no instability manifests whatsoever within that range hence why the 7.0" limitation is imposed, they simply don't need to go beyond it. in the more tail heavy Spitfires that need to go outside that CG range it is clear that a level of instability is deemed acceptable and controllable or they simply would not allow the paying public to get in to one and this limit is allowed right up to 12.5" aft in the hands of civilian pilots. So Crumpp please, we emplore you, provide this mystery MkIX report you claim to have, I honestly would welcome it no matter what it proves.

Not the case, no merlin powered spitfire has an increased elevator and taiplane, and the size increase on griffon powered spits is not a post war modification, there is no such thing as a griffon tail plane on a merlin spit.

it is the addendum to the last issued type certificate where the rear CG limit was increased because it has the rear fuel tanks fitted, really nothing to do with elevator design. complete enough. Proof enough that you are incorrect about restrictions on wartime CG ranges, this aircraft is now with planes of fame I believe, maybe you have more opportunity to investigate. Post war elevator modifications that don't exist on these marks? they all have standard elevators. many WWII fighters don't, including German ones, I have already linked a MkI certificate with no restriction on CG range and it is operated in wartime configuration guns and all, there is no mention of elevators being of a modified specification, I guess you need to get in touch with our authorities and tell them that they are just wrong.

No, they limited Vne because they only tested up to 340KIAS, they limited the CG by .5 inches which is nothing (sorry if that makes you insecure) to eliminate completely the adverse effects of instability.

I haven't linked a doc for a MkXIV, that was for a MkXVI. Here is one for a MkXIV which is even less restricted than your estimation. http://www.caa.co.uk/AANDocs/26870/26870000000.pdf interestingly though going back to your theory, yes they increased the tailplane area on the Grifon powered Spits yet that proved to limit the stability margin even more, yet another inconsistency to your theories.

Heres an interesting certification for a MkXVI (essentially a MkIX) with full wartime CG limitations and it is the bubble canopy version which was understood to present lateral (directional) instability at rear CG limits, not significant enough to limit it's civilian operations clearly. http://www.caa.co.uk/AANDocs/21359/21359020000.pdf

Heres an interesting report showing how a MkV Spitfire with absolutely miniscule adjustment to the wartime rear CG limit had all the minor adverse conditions presented by instability cured. http://www.caa.co.uk/AANDocs/21053/21053000000.pdf

Ok, heres some quantifiable data on the approval of full wartime CG limits on a modern MkIX Spitfire, sorry it takes me time, I don't have any of this stuff pre prepared to satisfy any obsessive campaign and I have to look it up in real time. http://www.caa.co.uk/AANDocs/17661/17661040100.pdf

I really don't see where the instawin uberplane idea comes from, nobody is asking for that, simply resisting the other argument is not asking for that, I want an accurate spitfire vices and all, I just don't believe the alternative argument and have more than enough information toto satisfy me that the other argument is pure fantasy.

Why are they less restricted for earlier marks? http://www.caa.co.uk/AANDocs/29100/29100000000.pdf interesting to read that in the absence of proper Mk1 documentation they have used MkV examples instead citing that a Mk V is just a Mk1 with a Merlin 45 arguably Mk IX's were just MkV's with Merlin 66's etc etc I think you will find they refer to the best available military certificates and apply accordingly, this really leaves much of the 'hard data' that gets thrown around here as somewhat redundant as some of it is clearly not the same data that official establishments use. A note from one certificate for another mark http://www.caa.co.uk/aandocsindex/21880/21880000200.pdf Really just shows that they will approve on the basis of safely demonstrated previous experience within the military and no restrictions are based on its civilianisation. It does leave the CG limitations on the current MkIX's a little bit of a mystery though they are hardly radical impositions.

hey it's not my video, what you call mistakes I call simplifications, and I am trying to help out a guy who doesn't seem to be familiar with the topic, my firs instinct is not to go knuckle deep into the guts of aerodynamics. it doesn't alter the concept of stability,

I assure you it's the message not the messenger.

You only have to see the level of obsession with this particular topic this poster shows across the internet, we don't even have a Spit in game yet so why start this topic? No aircraft flew on rails, there were instabilities in the Spit with a rearward CG just like any aircraft, it's the Spitfires light controls that made handling those instabilities require a touch of finesse, the same lightness made handling those characteristics so easy, you can hear Al Pinner say as much in the video, you could pitch too much with ease, you could correct it with similar ease, as mentioned the lightness was 'desireable' in a fighter and is primarily the aspect of the handling that Spitfire pilots both modern and historic would romanticise about, it's also what made the Spit harder to aim than more stable platforms ( note something being more stable does not make the Spit unstable) but certainly not very difficult, even English 'island monkeys' could shoot something down in a Spit. Yes I have faith in Yo-Yo and ED to create a spectacular version of any aircraft, I hope they cannot be influenced to neuter or boost any aircraft, they cannot ignore anecdotal evidence if the end result of cold hard data is wildly at odds with it, when it comes to validating a Spitfire FM then it should be easy to configure an in game one to a modern day spec and compare. I am in 7th heaven with DCS right now, absolutely fantastic warbirds and in VR :joystick: its the next best thing to the real deal, Crumpp's version of a Spitfire would not be. to clear up any ambiguity here is a video explaining aircraft stability that I believe is the hymn sheet everyone is singing from.

Indeed we do agree, it's just what Crumpp is trying to achieve is to make the Spitfire difficult for everyone no matter what level of experience. Anyway, we are not off the beaten track, we are still discussing Spitfire stability and handling characteristics.

Well if I ever do I wont be concerned about it, everyone I know who flies them certainly have no reservations about it's capabilities, you'd be surprised just how close to the edge modern day Spits have been flown by some of the private operators, the BBMF are certainly more cautious.

Most if not all Spitfires have wing tanks in place of guns so not far off, not flow the Spit yet myself. oh...:music_whistling:

Al Pinner is a colleague of mine, I have spoken to him about the Spitfire and will take his word over anybody here waving charts and raw data at me. They now allow the fare paying public to fly in Spitfires in the most unstable condition it is ever likely to have faced.

Sort of, stability is easy to handle for anyone right up to neutral, once entering the unstable range the test of ability begins, it is literally like and often demonstrated as balancing a ball, with more experience at balancing a ball one becomes better at it no? the stable condition is a ball in a bowl, you need some extra special skills not to be able to handle that, neutral stability is a ball on a perfectly flat surface, you have almost total control over its condition, instability is balancing the ball on top of a convex plane (finger, other ball etc) it can be done with relative ease subject to how far in to the unstable region you go and your capacity for balancing gets better with exposure.

It shouldn't be a stretch to do this retrospectively when that time comes (DCS 1946 :music_whistling: )

??? you seem to have completely misread it seems or are overcomplicating it. experienced = experienced i.e. someone who is regularly flying the type like an average line pilot would be, there is no mention of piloting 'skill' at all No, the 3 states are absolute according to the definition in science. No

yes it's a sliding scale, nobody is really suggesting otherwise, it ranges from stable to neutral to unstable.

if the recommendation was for line pilots to engage in combat with that fuel load then it's not difficult, the term experienced pilot is not meant as anything above average in skill, simply a pilot who is in current practice with experience, just as the typical squadron line pilot would be. I don't know if they had rear tanks in 44.

Doesn't matter if it does get the rear tank, once 34 gallons have been burned then there should be no difficulty in handling the aircraft.

OK, people who regularly fly spitfires tend to have experience on some of it's contemporary aircraft, there is one comparison for you. I didn't quite see you bicycle argument as helping the point either for what it's worth.