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Guest jonpoint

Break out the nitro pills, Jim - it's (almost) racin' t

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Yes folks, after a major breakthrough (getting over my stupidity), the GeeBee will be gracing the FU3 skies very soon. Sorry for the delays but things have been a bit hectic. Still a few little details to sort out but here's a peek of things to come :-beerchughttp://ftp.avsim.com/dcforum/User_files/3dd977006ddac156.jpghttp://ftp.avsim.com/dcforum/User_files/3dd978cc73fd8cf5.jpghttp://ftp.avsim.com/dcforum/User_files/3dd97903749493bd.jpghttp://ftp.avsim.com/dcforum/User_files/3dd9792b750d0faf.jpghttp://ftp.avsim.com/dcforum/User_files/3dd979577570b339.jpghttp://ftp.avsim.com/dcforum/User_files/3dd9798075f49022.jpghttp://ftp.avsim.com/dcforum/User_files/3dd979e57707220f.jpgA gratuitous sunset shot!http://ftp.avsim.com/dcforum/User_files/3dd97a1377679040.jpghttp://ftp.avsim.com/dcforum/User_files/3dd97a3f77d50a73.jpgJon Point*************************(effyouthree@hotmail.com)*************************

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Beautiful beast! (the plane, not you Jon). It looks like a fair proportion of the plane is just motor?

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Folks," a fair proportion of the plane is motor."Oh yes :-) About 450kg out of the ~900kg dry weight in fact :-eek. This has a number of effects:1. Land under power and don't touch the brakes until the tailwheel is on the ground.2. The above necessitates a much longer runway than you'd expect for something with a small wingspan. And don't bother with grass or dirt, unless it's 'ruler flat'. You WILL need at least 3kft.3. Due to the ridiculous amount of power available, simply rolling the throttle on too quickly at takeoff will cause a nosedive! Going straight from idle to full power will actually cause the plane to roll over :-eek4. Stall is ~100kts and if you ever get below ~120kts, make sure the power is ON. Below this, the plane slows quickly and falls like a stone :-(5. The light weight of the airframe causes it to be affected by turbulence and winds in a very 'ratty' way - everything happens quickly! Slow fps makes the plane appear to 'jump' around.6. Even though the fuse-mounted fuel tanks help to counterbalance the engine, keep the fuel load down because it actually makes the thing tail-heavy. FLYING with full tanks is OK, don't try landing or taking off though ;)7. After countless flights, takeoffs and landings, I am able to admit that I have only landed 'gracefully' on a couple of occasions and that many takeoffs resulted in a quick 'page up' before I slewed of the runway and hit something.8. From 7 above, it's obvious you need good rudder pedals if you wish to land or takeoff 'gracefully'. Keyboard commands just don't cut it.I hope that, rather than scare you all away, you now have so much adrenaline (OK, nitro for you, Jim!) in your systems from reading this, the only cure is to download the GeeBee when it's posted :-hahThat said, it WILL be an 'alpha' issue, released for comment and constructive input. Creating aircraft in your spare time is very time-consuming but rewarding (when it works). I cannot begin to fathom how much effort the 747 took for Ansgar - then he did the DC3!Counting down, I'll probably post it over the weekend or Monday. I'll have to 'coz I'm off to 'windy Wellington' (they had 160km/h winds the other day...) again for a few days next week.Jon Point*************************(effyouthree@hotmail.com)*************************

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This looks like a break-through!I'm curious about the flight dynamics. You explain the stall and minimum control speed above and your screenshots show it flying at 216 kias. I wouldn't expect it go that fast with non-retractable gear. I mean, while small wings allow (and, require) high speed there's this terrific parasite drag from the undercarriage. "Socks" on the wheels help streamline them though. I'm not pretending to know the Geebee at all -- I just see an aerodynamic paradox with small wings and non-retractable gear. It's clearly built for power and speed, yet the wheels are hanging out. Interesting :-)best regards,Hans Petter

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LOL, not many retractable gear ships in the early 1930's Hans...Don't forget there were two versions of this aircraft the R1 and the R2...The R1 had a 770hp engine and was built for close course racing (Thompson Trophy) and the R2 had only 450hp and was built for cross country racing (Bendix Trophy) with a more steamlined cowl and larger fuel tanks. Don't forget, horsepower does little to increase top speed, it takes drag reduction to do that.The R1 did set a straight line speed record in `32 of 294+ however. Not bad for lower altitude flying :-) Not sure where the specs are set on this FU3 model but I do know that the newest replica flying can land in only 1300 feet... touch down at 120 mph with a stall speed of 100 mph.(there's another item for the FU model, in this time period gauges read in MPH rather than knots).I did get to talk with Delmar Benjamin (who flys the replica) at the Cleveland Air Show and he says the new one is always landed on the main gear and never a three point landing as the originals were. A lesson learned early on it seems :-)As for sensitive controls, where is the CG set at on the model ?Original aircraft had it set at 22 - 24 % of the cord and the replica made first flights flying with it set to about 21% , still quite sensitive but better than orginal. They calculated and wanted to get it at 18% so that's not a bad idea for this one I'd say.If it's not there, some washout in the wings will also help with stability of the FU model.Climb performance should be at least 4000 ft per minute and this is where power to weight ratio really comes into it's own. Level flight speed of 270 mph should be had at about 30 inches of manifold with an available 40 inches. Here's a shot I took of Delmar Benjamin with his "baby" waitng to fly :-)http://ftp.avsim.com/dcforum/User_files/3ddbb3597f718e57.jpg

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Staggerwing wrote: Don't forget, horsepower does little to increase top speed, it takes drag reduction to do that.Yes, that's my point exactly and that's why I was surprised that a fixed gear aircraft would go this fast. I'm looking forward to trying out the Geebee :-)Hans Petter

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Oh yeah - lotsa drag :-) This makes it accelerate like crazy but hit a 'brick wall' at high speeds. You can really feel it. It's tricky on the ground (light, unstable), becomes a joy upon lift-off (like it's on rails) then...The drag is very obvious at higher speeds. Above ~160kts the plane starts to 'wiggle', as though about to 'trip over' the landing gear. This makes the tail jump from side to side which would probably be quite punishing to a pilot - you sit 'in' the tail... Delmar must wear shoulder pads :-lolIt's all power vs. weight. Lots of power to get the thing moving fast enough to use the surfaces. As mentioned here, the climb rate is out of this world! In fact, with full power on, it's virtually impossible to stall below 6kft ;) It does drop in turns though so watch those pylons :-eekMy reference to 3kft landing space is a recommendation for first time tryout. I'm certain, with practise, one could land this thing on a dime (well, maybe a quarter) - it's just very nervous during landing. As Delmar mentions in his book, flying it is fun but landing requires a 'Samurai's approach'. The elevators are subject to control reversal at high angles of attack so forget the 3-point landings - take your time and allow lots of space. I just didn't want you all smashing it on the first flight OK?This all just makes it lots of fun :-hah Please remember that this is an 'alpha' issue, based on the Mustang flight model. I welcome all and any feedback so that I may get it to a 'finished' state as soon as possible. The initial release uses some 'iffy' textures which are being sharpened as we speak but are still a couple of weeks away. So is the full cockpit. Looks like tomorrow to post :-beerchugJon Point*************************(effyouthree@hotmail.com)*************************

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>It does drop in turns though so watch those pylonsIs there provision to add lift from the fuselage ? The GeeBee has lots of lift from the fuselage shape and will do knife edge flight rather well..Looking forward to flight tests.. :-)As far as being based on the P-51 model... It has been stated that in use, the GeeBee wingloading is like a P-51 without the use of flaps. I'm sure it's not suppose to "wiggle" at high speed though :-lolWatching for the upload..

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Yes, it does knife-edge quite well. In fact, you can do endless rolls without too much pushing and pulling and it flies upside-down all day!The flight model DOES need cleaning up and I'm relying on feedback for that. Ansgar has explained that whilst we cannot alter the prop direction, it should be possible to reverse the engine torque characteristic. Just have to look at the existing differences between left and right then reverse them I guess. The 'wiggle' isn't THAT bad but it's noticeable. I find that backing off the power a bit from 100% helps a lot (would make the engine last longer too...). It's all too much right now - let's get it in the air and see what happens.It IS a lot of fun to fly, even if it's not 100% accurate.Jon Point*************************(effyouthree@hotmail.com)*************************

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Wonderful Jon! I am arranging to bring in a few extra emergency vehicles, and set up a medical tent at McChord. They have a nice long runway to test fly at.Jim

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Great news Jim!I've just been doing a bit of fiddling with the flight model. The breakup data and contact points were a bit strange (my fault). I decided to finish the crash models last night and, when testing them I found that things were a bit screwy - every time FU3 placed you on the ground, the tail broke off. I think it's OK now - I just have to land it (successfully) to prove it. If it's still weird, I'll just delete those contact points.Jon Point*************************(effyouthree@hotmail.com)*************************

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