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Post by chamm37 on May 19, 2008 22:48:03 GMT 10
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Post by Pij on May 19, 2008 22:53:55 GMT 10
That's absolutely beautiful! I did my taping along the wing for a little extra strength, but your taping job is very attractive.
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Post by chamm37 on May 19, 2008 22:56:35 GMT 10
thanks man but it even looks alot better in the flesh ae......the purple strips with the yellow makes the overlaps look like a dark green which makes it look sweet as but yer it is better when you see it for yourself..... ;D ;D ;D
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Post by jase on May 20, 2008 20:40:39 GMT 10
nice job mate. looks great
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Post by Vanders on May 20, 2008 21:14:49 GMT 10
Looks good mate, what cg measurement did you use?
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Post by felix on May 20, 2008 21:29:46 GMT 10
very nice effort mate! should be very proud of that.
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Post by chamm37 on May 20, 2008 21:32:07 GMT 10
yer i am felix...i am very proud of it.....it took me 5 hrs to cover it.....uuuuuummmmmmmm the CG measurement is now 175mm from the tip point on the nose...
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Post by Vanders on May 20, 2008 22:36:49 GMT 10
Finished mine on Sunday after being grounded at home with what turned out to be a cracked brake caliper. Followed Karl's (on RCG) suggestion of 8.5" back from tip of nose, which means I actually need to add a fair bit of weight behind the CG. When I tried this in around 60kph wind it constantly wanted to do back flips like it needed more nose weight? ? Any ideas guys?
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Post by chamm37 on May 20, 2008 22:46:26 GMT 10
yer no that is where i had my CG until i went for a flight......like i said mine is 175mm which is 7inchs from the nose and i have got a 70gram lead weight there......the whole plane weighs 640grams i think off memory...... and even still just throwing it around in the street it still glides at least 100m but i have to use a little bit of alerion to keep it going but still it goes well......testing it on this weekend so i will let you know how it all goes Vanders....but it should fly very well with the weight in the front of it and not in the back like you had it....oh and what is the weight that you are using....i have put mine just above the battery and sits purfectly on the battery and i have shaped it to the aerofoil so that it fits perfectly and is no distraction to the flow of the air.....allright i will test it out on the weekend but yer you have it way to far back mate
Regards, Chris
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Post by sean on May 20, 2008 23:23:02 GMT 10
Hey Mark - that does sound tail-heavy!
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Post by Vanders on May 20, 2008 23:45:33 GMT 10
Felix, how much throw are you using on control surfaces?
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Post by felix on May 20, 2008 23:46:44 GMT 10
truckloads mate lol.......about an inch(i'm a little physcotic ).by the way mate my bee is a modified original not a beevo.
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Post by Vanders on May 21, 2008 19:38:32 GMT 10
Mate we''ll catch up on Sunday & you can have a play & see what you think.
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Post by chamm37 on May 21, 2008 20:50:44 GMT 10
yer ok........i will catch ya there mate ;D
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Post by Vanders on May 21, 2008 22:28:49 GMT 10
Just thought I'd post this here as it relates to this thread;
From "The Predator" on RCG.
If you have a CG 8.5" from the nose on a quality build and the correct throws it flies GREAT, peerless in my opinion, as a fighter as well if built at 18ozs. I've seen and had similar problems with TONS of pilots flying Predator Bees and wondering why their wings do not fly perfect. These ships are VERY high perfprmance builds and can only meet their performance goals with a very aggressive CG, 8.5+", in my case on a BeEvolution. I've found repeatedly that the real issue amoung frustrated pilots is the lack of a quality tuning process and this is THE KEY to getting any ship to responded to input EXACTLY and acurately as comanded. When you know EXACTLY how the ship SHOULD respond and it responds differently despite a PERFECT tune, that is giving you clues about the air mass since the ships ALWAY responds consistantly, must be the air and that info is HELPFUL!
I have been designing and prototyping countless high performance ships for the last 3 months, some VERY narrow corded planks being in that mix. These are BY FAR the most difficult to tune properly with the cg and the aerodynamic center being within a 1mm of each other. Perfect leverage ratios between servo arms and control horns is critical to finding ideal rates. AND just a slight bit of servo arm differencial, say one servo arm a TAD forward of center and the other a tad back will cause a wing with a perfomance CG to turn on ANY STRAIGHT hard pull at speed due to the mechanical diff. in the servo arms deflecting the control surfaces asymetrically. There are many variations of mechanical differential and fixing those types of issues can be complex and unintuitive to the uninitiated. Here is a tuning guide I worked up for pilots unfamiliar with how to do a PERFORMANCE tune:
Bee tuning and trimming!
Here is the KEY to getting this stuff perfect. Start off with a CG of 8.5” and center ALL the radio gear! Then sub trim the servo arms so that they are about 10 degrees forward of straight up (angled toward the nose) and perfectly symmetrical. NOW, mechanically set up your push rod lengths so that the elevons are positioned for flat and level flight, about 15 degrees of reflex (angled up) from straight back and symmetrical to one another while the servo arms REMAIN about 10 degrees forward of straight up.
Then lower the rates, I recommend about 35% for ailerons and 25% elevator (if you followed the Predator Bee instructions concerning lever arm lengths on your horns and arms) now if you stuff the stick into a back corner it will not whip stall your wing from excessive rates/throws! It will also fly MUCH faster with minimume induced drag for manuvers while remaining AMAZINGLY agile! You'll see! Give it a toss; figure out what adjustments you need to get it trimmed out flat and level with Tx trim tabs THEN do it ALL AGAIN mechanically to get flat and level in the elevon configuration AND also returning the servo arms just how you set them up the first time, the position they should ALWAYS be so that they are about 10 degrees forward of straight up (angled toward the nose) and perfectly symmetrical if trimmed for flat and level flight. Repeat until flat and level flight is achieved with the mechanical adjustments. Then fine tune your rates to your specific flying preferences. Dive/tuck tests and inverted flight tests are the best ways to verify optimal CG placement and often ideal is behind 8.5”. Your ship should hold a dive without tucking (tail heavy if tucking) or pulling up (nose heavy if pulling up) and inverted flight should not take much forward stick at all for fast efficient inverted flight. Now you’re ready to KILL! and you can STUFF the stick for a FAST recovery and not have to deal with some funky whip stall either! Hope that helps! Karl
This stuff is COMPLEX and took me a few years of hands on experience in conjunction with training from one of the MOST technically minded mentors ever, Deamon/Ian. If you feel like an idiot for not getting this all right, I MUST BE a super idiot since it took me YEARS!
Long story short- I've had TONS of pilots get a kit or RTF from me, build it PERFECT, had it built PERFECT, and then lack the tuning skills to get it flying as inteneded. Then they tell me all about how I messed something up. To date, I have NEVER had a BIG build issue with an RTF EVER and if the P Bee instruction are SIMPLY followed the wing flies GREAT every time.
I simple verify CG, tune the mechanical and rates and, it flies PERFECTLY always. It is tough for me to stay positive and helpful when I get scape goated for turning out consistantly GREAT builds and giving solid advice. These ships are tough to tune, like ANY set up for super high perfomance!
About 80-90% of my flights now include DSing and my desigs have evolved to enhance this area of my flight with HUGE speed ranges and super agressive tunes on super aggressive ships (many quite high aspect ratios). The fly GREAT for their intended purpose with their intended pilot. Basically, my little and big freak wings and planks have turned me into a FREAK pilot.
I love this, it feels magic to percieve breaking the laws of physics or coming REAL CLOSE. I do not expect anyone who does not fly with me to understand this but, it IS the same reason these same pilots do not completely get the perfomance tune, it's a sensitive FREAK O Nature just like me! LOL
The truth is, I could never pull off some of the stupid stuff I do without a PERFECT performnce tune!!! I doubt ANY pilot could with a poorly tuned ship, its IMPOSSIBLE to retain energy on a draggy ship or have an acurate pull on a poorly tuned ship. Understanding trimming and tuning down to its essencial basics WILL improve you piloting accuracy BIG TIME, WAY MORE FUN and SATISFACTION or just get that little sucker flying at all to start with.
I really hope all this helps, it has taken me YEARS and 1000's of piloting hours to completely understand all these relationships completely with their affect on the flight and flight response itself. If I am consistantly doubted and blamed for giving good advice, I must stop.
I do this only to spread the love and enjoyment of our hobby. If my advice is misleading or not helping in any way I'm missing my goal and would serve us all better by just evolving in a vacum as I have been lately. I get a bit tired of being doubted despite huge repeated efforts to help as best as I can.
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