bongodriver

I am not chasing my own tail, I am successfully putting counter evidence to every single claim you make, it's easy really, I just don't cherry pick.

Yeah the math, a reduction of 5.2" from 12.6" is 7.4" aft of CG according to you own submitted Spitfire stability report on the MkIX, this ties in very nicely with the modern day MkIX's having the aft limit set to around 7.2" and the ones with rear tanks having a higher limit, I don't care what method you have used to complicate it, the real sauce is right there staring at us in the face.

but your linked report already shows that is not true, even in the worst case it's shown to be a reduction from 12.6 to 7.4 if all rear fuel is burned and that includes the weight of the empty tanks + plumbing.

it does not necessarily suggest that there was an issue with manufacturing tolerances, I'm sure now and again a complete lemon was made.....and shipped to the states so NACA could test it :harhar: it really just says that accuracy in manufacture is fairly critical....well duh!, at least we know the elevator itself is not responsible for the Stability of the design but more the controllability, be realistic, if it was already known that elevators needed to be made well and Spitfires were suffering for it then something would have been done to ensure quality. Ultimately even your linked report suggests the worst case is simply a limitation to the aftmost CG limits on production aircraft, limits that Spitfires were very unlikely to reach in combat, they only needed to burn half a rear tank worth of fuel and they were just fine for combat and well within the CG limits. Absolutely correct, the MkIX with a bigger engine had it's CG shifted forward (empty) and this means that loading it with fuel, ammo and a pilot did not shift the CG rear enough to maintain satisfactory handling qualities, therefore ballast is added to the rear to bring the CG in to the desireable range when loaded and ensure it doesn't shift too far forward with consumption of fuel and ammo. 25 pages and you still don't get it is even more ridiculous.

I didn't suggest you do. He joined in Dec 2014, but is a familiar character on most WWII aviation sim/discussion boards peddling the same message. I agree completely, absolutely no need for a thread like this one to be started at all.....unless they are trying to influence someone.

Apparently the only thing difficult about flying a Spitfire is getting someone to let you do it. Anyway, breathing deeply, aligning my chakras and contemplating the universe.

But that's the point, everyone who said they like the Spit say it because it's not tricky to fly, it is carefree in handling and gives plenty of warning of approaching stall. The reason this thread exists is because the OP has a personal hatred of the Spitfire and is obsessed with trying to influence developers to make his interpretation of the FM. There are people who flew the Spit in combat and loved it, there are people who flew aerobatics in the Spit and loved it, there are still people who fly Spits who aren't trying to kill anybody and they love it. I think I'm just being wound-up now, nevermind, we will see what we get.

Trust us, he is not describing a 'Chuck Yaeger' version of pleasant, the Spitfire is loved by all it's pilots and they are not all 'Chuck Yaegers', I have never read an account of a pilot not enjoying the Spitfires handling qualities and if there are such accounts they are in a very significant minority.

I'm jealous of him too, he could afford to pay for it :cry:, I make peanuts for doing the job.:pilotfly:

The one I fly is a 1942 N2S-3 Navy version, not quite as tidy as the one in your video, the Stearman is pure flying pleasure though. sorry about the music and 10 minute length, this is a vid of me (in the back) taking someone on a pleasure flight around the cliffs of Dover.

Actually it is logic, you don't add ballast in the back to increase stability, in this case the stability and controllability was the primary idea behind it, remember this is a fighter not a flying club aircraft. in the case of the MkIX the increased weight in the nose from the bigger engine increased stability and this was in fact undesirable, if an aircraft becomes too stable it loses manoeuvrability because it becomes harder to control because the stick forces are heavier (like the Me109) and has other detrimental effects too, the adding of ballast in the rear of the aircraft was intended to 'reduce' the stability (which is a sliding scale) by shifting the CG back closer to the Centre of lift (the engineering elite will call this Aerodynamic centre (AC)). A simple way to look at stability is: CG forward of AC = Stable condition CG equal to AC = Neutral condition CG aft of AC = Unstable condition The ideal situation would be close to Neutral, it gives absolute control without heavy stick forces and is not unstable, the down side is that the CG range must be carefully managed to ensure it won't slip too far in to the unstable range, and the aircraft is somewhat twitchy because of light controls, this is what the NACA MkV report suggests is the case. Instability increases manoeuvrability but causes the aircraft to become less controllable because the aircraft starts to over react to control inputs, that is why modern jet fighters are designed to be unstable, they just have to have computers to actually control them, the pilot is simply making a request to that computer when he makes a control input, because these conditions are a sliding scale of varying degree that means slight instability is not inhumanly possible to control but flying an unstable aircraft means the pilot will be overloaded and using all his skill simply in the task of maintaining control the aircraft and will not have the spare capacity for much else like combat/aerobatics etc etc (that doesn't sound like the Spitfire now does it?) but that is what Crumpp would like to see, Spitfires spinning out of control because the pilot coughs. This is a simplification, there are ways to overcome stability issues without messing with CG, but as we have seen in this discussion the thinking is based on the same airframe through the Merlin Spitfire marks, of course the MkV in the famous NACA report had an early elevator design so it's not as simple as taking MkV data and bingo we have a MkIX though I'm sure Yo-Yo is not telling us the full story of how he will achieve his results. Here's another video explaining some of the basic principles, the engineering elite need not jump up and down in disgust, centre of pressure and aerodynamic centre are always getting mixed up in these simplified instructional videos for student pilots, the point is that stability is a balancing act between the lift induced components and the gravity induced components.

Yes, arguing against it despite all the evidence. None of the stuff you just quoted appears in the AAN for the MkIX you just linked to, you are just making stuff up now.

apology accepted

Yes, that one after it's conversion back to full wingtips and it's subsequent airworthiness approval note in 1999, 3 years after your attached photograph. http://www.caa.co.uk/AANDocs/23951/23951000000.pdf Nobody is swapping anything, you just seem to be referring to the AAN issue2 which is a document covering this aircrafts withdrawal from airworthiness, probably due to subsequent export. this in in your issue 2 AAN What you seem to be conveniently ignoring is the original issue AAN states clearly the non-clipped wings minus bob weight and it has the 3.5" to 9.0" CG range still, pictures show clearly it has elevator of the late war mod 789.

So clipped wing Spits were perfectly stable, that was the magic bullet all this time? Anyway this is a Spitfire MkVc G-BUWA, I think it has now moved on from the UK and is N registered, plain to see are the regular wingtips and elevator mod 789. Lets see the difference between clipped wing and regular wing shall we? I see the regular wingtip version is allowed an extra 2" forward CG but has the same 9" aft CG. Oh and it still has no inertia weight. http://www.caa.co.uk/AANDocs/23951/23951020000.pdf I really can't wait to hear the next excuse :wallbash::wallbash::wallbash:

You just don't know when to give up. Elevator mod 789 is the horn balanced late war type as described in your opening post. you can see clearly that the Fighter collections MkVB EP120 has the late war elevator design. now have a little think about life as you read through its Airworthiness note, paying particular attention to the weight and balance where it specifies the elevator specific modification as the reason for increase in CG range, note the specific detail of 'no' bob weight installation. http://www.caa.co.uk/AANDocs/29299/29299000000.pdf

:thumbup:

of course you have just confirmed everything you have been arguing against, the MkIX is more nose heavy and becomes too stable, they add ballast to return it's 'desireable' stability and control characteristics.

Not quite what I was getting at, I have argued from the beginning that stability increases with forward CG, something that Crumpp has denied in the case of the MkIX, I also understand the function of the elevator balance. The elevator mod I mention does allow an increase in aft CG range according to provided documentation though, the same modification is present on the Fighter collections MkVB EP120.

I raised most of those points, yes the late war horn balanced elevators (Spitfire mod 789) are a significant factor that allowed the CG to move further aft to 9.0" in a MkV, the same elevator used in late MkIX's I understand you say the MkV is Neutral and there is no issue with that, it is Crumpp's claim that the spitfire is unstable in normal CG range that is the questionable theory.

OK, sorry, hopefully it is much clearer now? Again, sorry. I personally am not a console gamer and agree the thumbsticks would be practically impossible for me to get my head around, I don't just fly vintage tail draggers, I teach other people to fly them too, I should know the difference between aviation 'easy' and layman's 'easy'. Blimey, another apology, not meant to be facetious, I type much of my stuff while smiling because I think I'm being funny....someone has to think so eh?

Obviously for a trained pilot, why would they be drawing conclusions for people not likely to be flying an aircraft? Obviously the comparison is for contemporary aircraft, the test was done in wartime and NACA did not have time travel technology to determine if they would be making recommendations for game console players. Yes, apparently the key to success is to have a full mock up of each cockpit in game, that shouldn't alienate a majority of flight simmers at all, not that the requirement for scale hardware is strictly correct, you can be delicate with a short stick and get the same results.

you can discuss it all you like of course, it is however incorrect, the horn extensions on the elevators do increase the area of the elevator, there are simply no modifications to enlarge the tailplane, only Grifon powered Spits had a larger tailplane and it didn't even happen with the first versions. Yes, aerodynamic balancing. Is one of the possibilities, it also is used to reduce flutter, it all depends really, some aircraft have no balancing on control surfaces at all. Oh yes lets..... a single inertia weight with experiments at different weights on a few tests, none ever making production on a MkIX and only extensively used as a stop gap measure on MkV's due to bad loading habits creeping in to front line squadrons, there are even documents stating that the inertia weight is not to be fitted with a horn balanced elevator. 2 attempts, mass and aerodynamic horn, the latter being the continued choice. obsessive redesign is sort of the point of tolerance testing, however only 2 designs made production. I really don't think it took 70 years to create an elevator magic bullet. No evidence of this is provided in any form, none, nada, diddly squat, zero, sweet FA! Post war aircraft are regularly flying with wartime limitations in place, even the engine handling limitations are the same as wartime. Drum roll please....... :suspect: Fixed that for you, as it has been shown that within 7.0" inches aft of datum the spitfire is stable on all Merlin powered marks, the normal range of a Spit falls well within this range with exception of late Grifon powered variants.

a picture of the actual aircraft with the early standard elevator is not enough for you? it is the standard non horn balanced elevator as illustrated in a previous post, no Spitfire ever had a straight hinge line elevator, the earliest type has the 45 degree hinge break and is the standard. Absolutely not So, you get it now?, no horn balance, meaning the standard elevator with 45 degree hinge break. No bob weights are fitted, fuselage length is the same but the front cockpit is moved forward slightly, look forward to the data you gather and share though. I have not seen a single wartime limit that exceeds anything listed a modern example, so your claim here is just plain nonsense, we have however seen clear evidence of instability being eliminated at CG ranges of 7.0, this is not the normal range of a Spitfire and it does render your claim of Spitfire instability at normal CG range completely invalid. it was correct for that specific MkV, it's applicability to the MkIX is very tenuous at best

No, there was a wartime modification of the elevator that increases the area by including balance horns.