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Old Dec 13, 2012, 11:37 AM
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Originally Posted by Phil.Taylor View Post
"Nay" !

only when everyone agrees that the crucial ingredient in the "dive test" - which is most often forgotten, is:
- when you have changed the CofG after the first (or subsequent) dive tests you MUST now RETRIM the Tx elevator trim so that the plane once again flies hands-off in level flight - before you do another dive test

Phil.
Yah, on my wee Alula, the elevator throws are so vastly reduced (1-2mm) that a single click of trim yields a (relative) heckuva lot of throw, making it time-consuming to move the cg teeny tiny amounts to match the trim one beep "this way or that".
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Old Dec 13, 2012, 12:45 PM
Red Merle ALES
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Quote:
Originally Posted by cityevader View Post
Yah, on my wee Alula, the elevator throws are so vastly reduced (1-2mm) that a single click of trim yields a (relative) heckuva lot of throw, making it time-consuming to move the cg teeny tiny amounts to match the trim one beep "this way or that".
Your Alula has a very short tail (moment), thus very minor changes in balance make a big difference!

Curtis
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Old Dec 13, 2012, 01:04 PM
Detail Freak
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A tailless plane is not really in the scope of this thread, which has more to do with decalage and CG.

R,
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Old Dec 13, 2012, 01:45 PM
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Originally Posted by target View Post
A tailless plane is not really in the scope of this thread, which has more to do with decalage and CG.

R,
Target
Kinda...
Just emphasizing one single point that was made regarding CG and trim....which has a LOT to do with why I started this thread...how to get my plane to fly right (neutralized) because it was always seeming to do something different than what I was wanting it to do.

Granted, the nit-pickers/forest for the trees type have created a stampede of "information" of which IS truly appreciated, but almost all of it hasn't helped because it turned into a whirlwind of stuff that is meaningless to a dummy like me.

On my "tailed" plane, the dive test/adjust/dive test/adjust method got my typical plane with typical pilot on a typical day quite happy indeed. (Ijust haven't had ANY chance to even fly, much less have enough wind to fly the inverted test.

Observation of what the plane is doing and changing it to do something better doesn't seem magical or have anything to do with unicorns. They fly better now!!!
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Old Dec 13, 2012, 01:47 PM
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FWIW, I have enough links and such here to last me awhile to read. I haven't read but a fraction, and may not at all....but that's just me...a dummy.

Thank you for all the input. Thread closed.
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Old Dec 13, 2012, 08:10 PM
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I was feeling quite a few different emotions as I closed this thread, and I think I did it immaturely... it just seemed to end up being a silly Ford vs Chevy-like pissing match. (Granted, I've involved myself in plenty of those over the years and so am just as guilty)

But the main feeling is guilt: for closing it immaturely because, A) I don't understand most of what y'all are saying, and B) Who am I to say that nobody else can learn from all of this?

I cut learning short because I stopped with what I was originally wanting to get out of this thread... getting my plane to fly better. Is it the best best now? Surely the answer is no! But am I pleased with it? Yes!!

So it all morphed into a life of its own and I shouldn't stunt its growth. I apologize for acting rashly.
We all have our views, can't exactly force someone to see it our way, and there's a good chance we won't change our minds...so what? Valuable information is being shared, and who knows? Maybe in time i'll read back on this thread with more in my head and have some Aha! moments myself.

Please carry on with discussion, please forgive me, and please be nice.
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Old Dec 13, 2012, 08:29 PM
MrE
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Thanks!
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Old Dec 13, 2012, 09:14 PM
Ricky Windsock
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Great .... The entertainment can resume....
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Old Dec 13, 2012, 10:02 PM
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The Middle East will be at peace before this war is settled, but they both started about the same time...
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Old Dec 13, 2012, 10:29 PM
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Slightly different direction...

I have a free flight Multiplex Fox (RC now and only tossed once/"landed" once) whose wing's incidence is notable higher than the stab.
What sorts of flight characteristics will this setup have compared to if/when I adjust the wing down to match the stab?

FWIW, the stab and wing are both up, so the fuselage is a bit nose-down when tail/wing approx level.
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Old Dec 13, 2012, 11:29 PM
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Originally Posted by cityevader View Post
Slightly different direction...

I have a free flight Multiplex Fox (RC now and only tossed once/"landed" once) whose wing's incidence is notable higher than the stab.
What sorts of flight characteristics will this setup have compared to if/when I adjust the wing down to match the stab?

FWIW, the stab and wing are both up, so the fuselage is a bit nose-down when tail/wing approx level.
That's a good experiment. You will need to move the CG to achieve trimmed flight as you change decalage, and you will end up with different pitch stability. If you try and tell us what you see, it would be invaluable.
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Old Dec 14, 2012, 04:34 AM
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Originally Posted by cityevader View Post
I was feeling quite a few different emotions as I closed this thread, and I think I did it immaturely... it just seemed to end up being a silly Ford vs Chevy-like pissing match...
Hello cityevader

I think you were right to shut the thread. Think you got all the answers you wanted though you may not understand everything, it also applies to me. We've been served some good links from eg. CloudyIFR, http://www.moneysmith.net/Soaring/soaring8.html
Questions not answered within 10 pages here on RCGroups is not worth reading, but that's just what little I think.
I will continue to follow this thread, but mostly for entertainment.
Good luck and hope you / we become wiser after every post.

/Ville
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Old Dec 14, 2012, 10:20 AM
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In the year 1997...

Those articles were written from a perspective from the past. Past models past radio equipment hex even from a time when airfoils varied.
I doubt there was a carbon pushrod or digital servo in play for Bradley Smith.
There is some good general info for the novice there to bud on for sure.

His comment about the inverted test completely misses the mark , since it was done to determine incidence caused by excess nose weight - not to SET the deadly "neutral" balance point.

No contest pilot would ever want a sailplane that was harder to fly or took More concentration to fly well in all conditions! We want the EASIST flying ship we can get.

Balancing a task sailplane today takes only a couple of flights because we don't set CGs for some mystical performance advantage or to make our models do the flying for us. In those days a lot of time was spent diddling with CG since the alignments changed with air temps!

As long as the stab a full flying stab guys will be able to set it according to their "beliefs" versus for communication of lift and sink versus airspeed changes.

But as I mentioned earlier many of the latest ships are coming with fixed horizontal stabs and articulated elevators so those of you looking to use nose lead and decalage to do your flying will have to start shimming tail mounts.

If you believe in you words/replies sign your name to your posts and add your photo. Include your credentials...LSF Level, contest wins,articles published,and current contest ship being flown. So like readers can see ( like all the soaring world can see for me) how much value can be applied to your opinions.

Miami Mike - you somehow gleaned that I said I was a better contest pilot than Tom Kiesling because I was there in Calgary to root for our team... In fact I am not a very good contest pilot....and yet I managed many more than 3 LSF5 wins.
Because I studied and practiced.

I didn't stand against opposite opinions about balance, setups,practice regimes,landing patterns, etc -

I tested them. And it lead to wins.

I am not smarter than any one else, but likely I do have more thumb time with guys who are smarter than anyone else in the hobby.

Want to be a better sailplane pilot? Quit arguing, go to the field and test what I offer. Then bring back improvements to my tips.
Gordy
One more good day of soaring in Louisville left before the end of the world.
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Old Dec 14, 2012, 11:44 AM
Red Merle ALES
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Originally Posted by Francesco View Post
That's a good experiment. You will need to move the CG to achieve trimmed flight as you change decalage, and you will end up with different pitch stability. If you try and tell us what you see, it would be invaluable.
Would you please explain how chaning decalage affects balance or vice versa?

I can see how it affects trim; whether a full flying or articulated horizontal tail.

Thanks
Curtis Suter
Montana
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Old Dec 14, 2012, 11:47 AM
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Originally Posted by CloudyIFR View Post
Would you please explain how chaning decalage affects balance or vice versa?

I can see how it affects trim; whether a full flying or articulated horizontal tail.

Thanks
Curtis Suter
Montana
I didn't say it effects balance directly.
But if your plane is trimmed for a certain AoA, and you change its decalage, you will need to re-balance it if you want to be trimmed for the same AoA (in straight and level flight, that is). If you settle for a different AoA we're not comparing apples to apples.
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Last edited by Francesco; Dec 14, 2012 at 11:51 AM. Reason: Edit: sorry I misread your statement
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