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RTWR 2006: On Aircraft Eligibility

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Hi All,Pending the return of our website, here is some more information:------------------------------------------------------------------RACE AIRCRAFT ELIGIBILITY.Each year the Committee must consider which aircraft are eligible for the Round the World Race. Our basic principles are "fun and fair" in that we want people to fly their favorite aircraft and that the process be fair for everyone. In addition, we stress realism to the extent that the race is still fun and fair.During the Race, the Committee will consider challenges. If anyone feels that an aircraft is not eligible for the race, you should submit a challenge. You should state your objection and include any relevant documentation. Others will have a chance to respond quickly. The Committee will take appropriate action.Here are some decisions made before the Race begins.AIRCRAFT TYPES NOT ELIGIBLE IN 2006:V-22 Osprey. Not enough examples in active service.The F2G (Goodyear's last version of the F4U Corsair). Ten were put in service, but those were in testing at Patuxent NAS and found deficient in handling--and decommissioned within two years. Its fame lies in low-level circuit racing.)Fw 190-D11 and Ta 152C. The D-11 is labeled as a prototype by Shockwave in their documentation. Apparently 7-13 were built (Shockwave says 7) but we don't know much for sure here--this being a late-war on-the-fly aircraft. The TA 152C is a prototype. (The Fw 190-D9, Fw 190-D13, and the Ta 152H are fine.)AIRCRAFT MODELS NOT SUITABLE FOR RTW 2006 RACING:The decisions here do not necessarily reflect on the overall quality of any aircraft model. The design of FS aircraft necessarily involves many compromises. Understandably, many designers choose not to design for performance right at the edge of the flight envelope. But that is where the Race is run. So we shall be in a position of finding some aircraft unsuitable for RTW Race even if they are otherwise excellent aircraft. And, of course, reasonable performance at the edge does not necessarily recommend the aircraft for other purposes.Beech Starship. (Mike Stone).See below.Piaggio P.180 Avanti. (FSD).See below.Lockheed Constellation L-1049G. (Mike Stone and Rey Lopez models.) Various reasons having to do with unrealistic power, speed, and fuel economy. Constellation pilots should use the Mike Stone visual model with the Wolfram Beckert airfile (and the Hansjoerg Naegele-Jan Visser panel). Look for vcon20.zip and follow the instructions carefully. A complete package of 3D model, airfile, panel, and sound is available at FligthSim.com. Look for Luis da Costa Pereira as the compiler of the packages for the L-1049G and EC-121.ATR72 (ARNZ) Jon Murchison. This ATR72 is 100+ kts too fast. There exist lots of realistic alternatives. For freeware, look for the excellent version by Francisco Sanchez-Casataner. The FlightOne payware version is a real favorite.Models by Kazunori Ito (several):Kazunori Ito is known for his outstanding 3d modeling and painting skills. However, our experience with his flight models indicates that they are not suitable for RTW Racing.--------------------------------FORMAL NOTICEBEECH STARSHIP (Mike Stone) and PIAGGIO P.180 AVANTI (FSD)The racing speed of aircraft is limited by both the power plant and the aircraft structure. The latter is governed by FS's "Overstress" parameters found in the aircraft.cfg file: max_indicated_speed and max_mach. (Also fromFS2002 in the airfile.) The best official sources for numbers such as these are the FAA Aircraft Type Certification Sheets (http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/MainFrame?OpenFrameSet )The maximum mach numbers (Mmo) need no explanation. The max_indicated_speed is more complicated. The current standard is the Maximum Operating Speed (Vmo). This is apparently what Microsoft uses for their default aircraft. However, the older standard is the Never Exceed Speed (Vne) which is also used by aircraft designers to limit the aircraft airspeed.THE BEECH STARSHIP (Mike Stone original & Alaskan Winds modification).The Mike Stone Beech Starship (including the version with the Herb Morse Alaskan Winds modification) is not only too fast (in terms of power plant) but it's max_indicated_speed is not close.For a comparison:FAA Starship: Vmo: 250 Mmo: 0.60Stone Starship: max_indicated_speed=385 max_mach=0.65Rather than ban the Starship or require that the max_indicated_speed be set to 250, the committee has decided on a compromise for this year's race.Pilots must edit the aircraft.cfg file and enter (or replace) the line max_indicated_speed=385.000000 // Original numberswith:max_indicated_speed=300.000000 // RTWR 2006 numbers(Look for "Reference Speeds". Be sure to make a backup before editing.) Pilots may not alter other flight characteristics in the aircraft.cfg file. This "Vmo/Vme" Speed Limit will be reported by the Duenna, but the system basically works under "pilot's honor".This one-year ruling allows pilots to fly the Starship at something approximating full speed but requires care at low altitudes.THE PIAGGIO AVANTI (FSD).The story is similar for the Piaggio Avanti.FAA Avanti: Vmo: 260 Mmo: 0.67FSD Avanti: max_indicated_speed=325 max_mach=0.70To fly the FSD Avanti, pilots must edit the aircraft.cfg file from:max_indicated_speed=325.000000 // Official FSD numbers to the following:max_indicated_speed=310.000000 // RTWR 2006 numbers These compromises are designed to allow two old favorites, the Beech Starship and the FSD Avanti, to compete fairly in this year's race. This is a one-off adjustment. The Committee promises much closer scrutiny to the issues of unrealistic speed limits and unlimited maximum power (full time combat power or WEP) in piston engines for next year.

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Correct, this ruling seems designed to give other teams an unfair advantage.Restricting Mike Stone's B2000 is correct though, as the flight dynamics on that one are completely unrealistic.In fact, I and several others on this team tested it individually for last year's race and decided to not use it because it was woefully unrealistic, despite giving performance that might have won us the day.Had the Avanti been similarly poor we'd have decided the same about that one.

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Jeroen and Jeff-First, I want to assure you that by no means was this an attempt to give the other teams an unfair advantage. Our only concern was ensuring that only realistic aircraft are allowed to compete in the race. This rule applies to all the teams, not just to Avsim.Secondly, in response to Jeff's statement that the real-life Avanti can fly faster than the FSD model: This is incorrect. The numbers quoted on the page Jeff linked to were groundspeed numbers. The numbers we were dealing with in the flight test were indicated airspeed numbers. The difference between groundspeed and indicated airspeed consists in two parts:Firstly, indicated airspeed must be corrected as the aircraft rises in altitude to true airspeed. Since the air gets thinner as one climbs, smaller amounts of air in the pitot tube represent the same speed. If you've flown on airliners in FS I'm sure you've noted that at cruise you may be at Mach .8, with a speed over the ground of over 500 knots, but your airspeed indicator rarely reads above 300 knots. This is because airspeed indicators are calibrated to read correctly at sea level. 300 knots of sea-level air is equivalent to 500 knots of cruise-level air. To see this relationship in action, check out this website: http://www.csgnetwork.com/tasinfocalc.htmlThe second part of the IAS to groundspeed conversion is tailwind, and the Avanti that Jeff linked us to almost assuredly had a tailwind on its record-setting flight: it was flying West to East across the heart of the US. This is typically where the jet stream flows, and the jet stream can add over 100 knots to an aircraft's speed.To prove to you that the real-life Avanti wasn't flying faster than 260 knots indicated, as both the Committee and the FAA say it isn't legally able to, here are the calculations showing how the groundspeed was achieved:The service ceiling of the Avanti is 41,000 feet. Let's assume that on the record-setting flight, Mr. Ritchie flew at 250 knots at 35,000 feet. Using the TAS calculator I linked you to, you can see that this gives him a True Airspeed of 425 knots. Add 75 knots of tailwind (which is completely in the realm of possibility when considering that the Jet Stream typically runs at over 100 knots and always runs from West to East - the direction of Ritchie's flight) and you get 500 knots: almost exactly what was reported by Ritchie as his speed. You too are allowed to do this same flight, and we've even allowed you to go up to 310 knots, in concession to the nature of the default FSD flight model. If we had allowed the FSD numbers, you would be able to go up to 340 knots of Indicated Airspeed. This would give you a speed of 578 knots, more than 150 knots faster than the actual FAA-mandated maximum value for the Avanti. This is clearly not realistic and clearly not appropriate for an event in which having realistic speeds is of paramount concern.I hope I've convinced everyone that we're not fudging numbers, and that the FSD numbers do in fact allow a pilot to fly well above the FAA's mandated maximum speed for the aircraft in question. I suspect that this was FSD's effort to guess where the Avanti would actually rip apart. Since no one was any way of knowing what this actually would be unless they're willing to sacrifice an airplane, it's clearly best to simply use the FAA's 'do not exceed' value, as this is a concrete, definitive number. In concession to FSD's value, we split the difference between the FAA and FSD numbers.I hope this clears everything up. If anyone else has any further questions or appeals, feel free to contact me via e-mail or forum.Best Regards-Matt SmithFor the RTWR Executive Committee

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Jozef-I'm happy to discuss whatever part of this rule you'd like. Bear in mind that we're aware of the upset ourselves and are prepared to take corrective action if necessary. This said, we did put in a lot of thought on this rule and at this point we think it adds a lot to the race strategically.Initially after this was proposed I was cold to the idea, but after thinking about the strategic implications and possible fun challenges that it brought with it, I warmed up to the rule.Also, please keep in mind that this rule is a *special* rule for this year's race and will *ONLY* affect this year's race. It's not as if we're saying all RTW races henceforth must be conducted below 8500. It's just a special challenge for this year's race, to keep things interesting and challenging. We will undoubtedly go back to normal altitudes in future races.As I said above, if you have any specific objections to the rule (even if it's just that you think it's too onerous) I'm absolutely open to whatever you have to say.Best Regards-Matt Smith

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Just to make it official, shall I presume that the XF-84H Thunderscreech is still banned for being a jet-powered prop? (in addition to being an experimental aircraft of which only a few were ever built...)

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Matt,I was unaware that the jet stream winds frequently reverse direction in a single day. From the link:"1, 2, 3 records

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unacceptable. I've never been able to reach close to those numbers in the FSD model no matter what the winds.This is clearly an attempt at putting us at an unfair disadvantage, as has happened often in the past (including during the race by suddenly changing the rules on us).Your intent is clearly to this year not have a race that's an interesting challenge in planning and airmanship but a follow the leader in which one team needs all the help it can get to win.I'm not interested in such a charade. If the rest of this team stays I'll help them any way I can but I strongly suggest in that case that we refrain from ever taking part again in events like this as clearly the race organisation cannot be relied upon (as has already been indicated by their past decisions, this was merely the one that went too far) to be fair and unbiassed.

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Thanks Jeroen I can clearly see why one set of rules that extend to all teams could be construed as unfair and biased towards one team over the other...Tony G

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Jeroen:First, PLEASE read through this entire post. I'm not sure you've read everything I've said to this point, as if you had I'm pretty certain you wouldn't be quite so angry, but it's important that you read everything I have to say in at least this post.For your and everyone's benefit, I will post here what I sent to Jeff earlier (he sent me the same post via e-mail)://Begin Quote//Jeff,Denver to Omaha: West to East.Omaha to Chicago: West to East.Denver to Chicago: West to East.http://maps.google.comNot sure where you're getting the notion that Denver is east of Chicago.Also, it doesn't say that the flights happened on the same day, does it?At any rate, the flights are all with the Jet Stream, as I said.If you can find me evidence that suggests that the Avanti will fly faster than the FAA's Maximum Operating Speed of 260 knots I'm more than happy to hear it.As for your inability to come close to those speeds: this is really a result of the aircraft's thrust/drag ratio as modeled. The only change we ask you to make is to the speed at which the airplane overstresses. This won't affect whether or not you'll be able to get up to those speeds. The speed the engines give you has nothing to do with the modification we're asking you to make. Seriously, this is a whole lot of fuss about nothing. You're going to get exactly the same performance you've always gotten. As long as you've not been crazily overspeeding (going more than 100 knots above the red line, and from what you say this doesn't even sound possible) you'll not see any difference whatsoever. So I'm not sure what the objection is.The link you sent me doesn't work. If you could copy and paste what it says that would be better.I sense a tone of anger on your part, and I'm not certain why. I'm happy to discuss this and any other issues you have with you, and in fact enjoy exchanging thoughts such as this. I hope I've not been patronizing or impolite to you. If I have been, please accept my deepest apologies.Best Regards,Matt//End Quote//In response to your allegations that we're putting you at a disadvantage, I'm honestly baffled as to how you could possibly construe this from what we've done. Seriously. The modification we're asking you to make has to do with the speed at which the aircraft overstresses. It has absolutely nothing to do with the speed that the airplane can achieve in level flight at maximum thrust - or at any attitude and thrust, for that matter. We're not slowing your engines down, we're not adding drag, we're not encumbering you in any way! Unless you're in the habit of flying more than 100 knots overspeed, you will see no difference whatsoever in the flying characteristics of the Avanti. Let me state it again, for the record:THE AVANTI WILL BE AS FAST AS IT HAS EVER BEEN IN THIS YEAR'S RACE. THE ONLY MODIFICATION YOU ARE MAKING HAS TO DO WITH WHEN THE AIRCRAFT OVERSTRESSES, AND DEALS WITH A REALM OF FLIGHT THAT YOU WOULD ONLY ENTER IN A SUICIDE DIVE.WHAT WE HAVE DONE DOES NOT SLOW YOU DOWN. IT ONLY SPECIFIES THAT IF YOU GO TOO FAST, YOU OVERSTRESS. IF YOU FIND THE PLANE TOO SLOW, TALK TO FSD.Seriously, fellows, this is a lot of hullabaloo over what amounts to nothing in the end. You're going to be going the same speed as always.If there is still anger or dissatisfaction over what we're asking you to do, I'm happy to address it, but PLEASE, PLEASE state specifically what you're objecting to and why.You state that we've acted against you in the past, or that we've 'suddenly changed the rules on you.' I have not the slightest clue as to what you may be referring to. I swear to you, I've never willfully made any decision to hurt your or any other team. We set the rules for everyone, and we do our best to make them impartial. If we suddenly change the rules, which we do our level best not to do, we change them on EVERYONE, not just on Avsim.You accuse us of trying to hurt you. What would my motivation be? I don't run in the race anymore, I don't cheer for any team, I don't care who wins! My only concern is a fair race. Further, Mike MacKuen is on the Executive Committee and he DOES race for Avsim! Do you think he's going to stand idly by if we're trying to screw his team over?I understand that you're very passionate about the race, and that's awesome. We all appreciate your enthusiasm. I also understand if, due to a misunderstanding, you've been given to believe that we're trying to hurt your team with rules. Please take a minute to examine everything I've said and examine exactly what the rules say and mean. I'm positive that you'll find that we've not hurt Avsim in the least.Finally, I want to let you know that your comments have hurt me in a deep and personal way. My only goal is to serve the community by running a fair and fun race. I've spent much of my free time over the last few months working through proposals and rules drafts, setting up the website, and preparing for the race. It hurts me when you say that, in spite of all my hard work, what we've done is 'unacceptable' and that we're 'clearly' biased against you. I swear to you that I'm not trying to hurt your team and that I'm just doing my level best to make the race as good as it can be. It hurts me when you attack our hours of hard work in such a callous and thoughtless manner. I say this not because I object to criticism. I call for it, because it's needed to make the race better. I do, however, object to unfounded attacks on my own integrity. I use the word 'thoughtless' because I think that if you had actually thought through the issue instead of hastily posting an attack, you would have realized that we're not actually doing your team any harm relative to the other teams. Also, you probably would have realized that Chicago is east of Denver and that therefore Jeff's argument is completely unfounded.I apologize for whatever miscommunication on our part caused you to be so angry with us. I ask that you examine this issue and reconsider your position on it.On a personal note, I hold no grudge from this exchange. I know that you're a passionate person and I appreciate that about you. I hope that we'll be able to come to terms over this and move on to enjoy this year's and future races.Yours in the hope of reconciliation-Matt SmithPS - As you may or may not have heard, we've received the 'Avsim proposal' and are giving it full consideration. As I mentioned to Chris in my reply, I promise that we won't reject it outright but will open a dialog with you if we find it unacceptable (Note that I'm NOT commenting on whether or not we're likely to find it unacceptable, I'm just stating what would happen if we did.) I hope that this further shows our open-mindedness and goodwill toward Avsim. (Note that this extends to all teams, not just Avsim.)

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Jeff,I'm sure you got my e-mail so I won't repeat myself there. Your link now appears to work, however, so I'll comment on that:The speeds listed are 'Speed over a recognized course' - in other words, groundspeed. This is exactly what I said they were above. As I explained above, it's eminently possible to acheive these speeds while remaining under the FAA Vmo of 260 knots. The fastest speed listed is 927.4 km/h just over 500 knots (http://www.google.com/search?hl=en&q=Convert+927.4+km%2Fh+to+knots&btnG=Google+Search)- this is consistent with what my calculations predicted was achievable. Our modification changes only the Vmo value: it sets it at 310 knots instead of the FSD value of 325 knots. All this means is that your aircraft will overstress in flight simulator if you exceed 310 knots of indicated airspeed as opposed to 325 knots before the change. The FAA value for this speed is 260 knots. As you've said, the FSD model doesn't even let you get close to 310 knots, there is no effect on the speed you'll be able to fly at in the race. We're asking you to do it for the sake of realism.Hope this clears things up,Matt

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The VMo value set in FS causes immediate catastrophic structural failure. As we've encountered many times in testing as well as during the race last year this can be reached easily by accident even when staying far below the stated value due to sudden pressure or wind changes caused by weather updates.I've crashed frequently when flying at speeds BELOW the barberpole due to this phenomenon.The FAA value is set at the value at which the aircraft may start to accumulate structural damage and needs to receive a thorough check if exceeded.This is far from the same thing. Effectively it means that below that speed the aircraft is certified to not get damaged due to aerodynamic forces or engines performing over their rated maximums.I appreciate your effort but the rulings of the race comittee over the last several years have left a bad taste in my mouth and at some point you just took it over the edge.The restrictions you're placing now seem to restrict aircraft you know we (as this team) prefer while allowing aircraft possibly preferred by other teams that we know are far less realistic.(For example as you may have been made aware of the new freeware P-47 which was allowed for the race despite being introduced too late which during our testing was found to be heavily overpowered while at the same time having a fuel burn which is far below that of the real aircraft. This meaning that this model will achieve speeds far in excess of what it should while maintaining greater endurance than it should, the exact same reason you're restricting one of our favourite aircraft, yet this model receives no such restrictions whatsoever).At the same time the altitude restriction hampers the use of turboprop powered aircraft, effectively reducing them to performance at or below that of reciprocating engines, again this team used in the past a larger proportion of turboprop powered aircraft than any other.Nothing personal, just a general feeling increasing over time that there is a bias among the race organisation.

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I stand corrected on direction of flight. I do not agree with the mod.I will not use the Avanti in the Race.Finally I would like to state that I do NOT think any member of the Race Committe is acting in an unfair manner. I think the enitere approach of aircraft certification for a race is problematic. Good luck to you.Jeff

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MattI did my own testing last night and can confirm all you said is true. This change only affects the plane if it goes over the barberpole (which "realistic" pilots wouldn't do any way). In fact managed to get 540knts out of it at FL360 witha high tailwind :)This is all a little irrelevant anyway, as no-one will be using the Avanti anyway with a 8500ft limit, as it's a tortoise at this altitude

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Jeroeon,Thank you for clarifying your position.All you had to do was challenge our ruling on the Avanti with that objection and appeal to get the freeware P-47 disqualified.I can only act about what people tell me. Please don't think that because we didn't rule on the P-47 we're in some way biased, it's just that no one challenged it. The reason the exception was made about allowing the updated model was that we released the rules ourselves after the 14-day deadline, so clearly we couldn't expect people to comply with it this year. If there's an aircraft you want to use that was released after this deadline I'm happy to extend the same courtesy to you.Here's where we stand now: I will speak with the Committee about the modification. If we determine that what you say is true and the Vmo value can cause crashes at speeds below Vmo, we will change things.Do you wish to officially challenge the eligibility of the P-47? You claim to have data showing that it is unrealistic. I would be most interested to see it.Best,Matt

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Jeroen,As we've encountered many times in testing as well as during the race last year this can be reached easily by accident even when staying far below the stated value due to sudden pressure or wind changes caused by weather updates.I've crashed frequently when flying at speeds BELOW the barberpole due to this phenomenon.I find this suprising and interesting.I've flown the FSD Avanti for a few hundred hours and had less than five crashes due to overspeed. In last year's race I made three flights where I kept the aircraft within one or two kts of overspeed. (Only one was an offical flight - one was a test and one I blew the landing).I never use the autospeed - when flying near the barberpole I keep my hand on the throttle ready to pull back and pull back on the props if the speed jumps. For normal flying I set my speed 30 kts below the barber pole - which is approximately where the real world Avanti pilots I get to talk with tell me is a reasonable speed - and the FS weather changes have never caused an overspeed / overstress crash at those settings.There is also a setting in FSUIPC to smooth the sudden weather changes which helps with the hard boundaries FS has for weather stations.Frankly in my testing, the Mike Stone Beech Starship with the Alaska Winds config file is much more prone to overspeed crashes than the FSD Avanti at altitude.You've reported issues with this aircraft several times over the past year - issues which almost no one else seems to be able to confirm. I'd like to have a side discussion with you after the race is finished - specifically about your system configuration and some of your addons.Let me know if you are available.Thanks,Reggie

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Several people last year (and again this year during training) encountered sudden overstress situations in the Avanti when flying her below the barberpole (which is set well below the structural limit of the airframe as we all know).Usually these seem to happen just after a weather update or moving from one reporting station to another, making me believe it has to do with pressure differentials.These we have now identified are also the most likely cause of the problems with Concorde when crossing the Atlantic. They always during our testing appear at the same points on flightplans (flying the same plan several time the problems happen at just about the same distance from the same waypoints when approaching the US/Canadian coast whenever there is a low pressure area over the first reporting station after the Atlantic weather gap).Even more damning, two people crashed last year in the Avanti due to this phenomenon in roughly the same spot over the North Sea when one took off to replace the other on the flight from Norway to the UK.I was one of those people... And that was the third I think crash I had during the race flying the Avanti, and at the time I never flew her above the barberpole.The aircraft has now among us gained a reputation as being a speed demon but very sensitive to overspeeding, and I for one will constantly fly with one hand on the throttle to avoid that (I too don't use the autospeed setting on it).

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Yes the hard boundaries of weather zones are well documented, at least in the AI community.The "border" around the UK is one - the North Sea change can be drastic. That was the only time I slowed my flight out of ENOV when I came to that boundary - also flying at FL270-290 was faster that night than higher up. Having a scout 30 minutes ahead really helped. Still wish I hadn't hosed the landing at EGLC.Another boundary is within about 200 nm of Greenland where those weather stations kick in.And as you noted near Canada.One of the biggest "issues" with FS is mid-ocean weather stations a few hundred miles from any other weather station. Bermuda is one of those.Of course in general the higher the latitude - the more likely there will be significant changes in weather.One of the techniques I use is to check my route on the weather map screen and see if there are weather stations which will be near my long overwater flights. That gives me a special warning to be prepared for sudden changes. Just part of my pre-flight planning routine.

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>> the Thunderscreech is still banned Aww no, can I appeal.... again? ;-)

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I'm actually just about to start to run a series of tests in the Avanti in various scenarios, using both the default numbers and the RTWR'06 mandated numbers. Will take several hours, of course, but will report on my findings......

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