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Old Jan 18, 2009, 06:16 AM
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andreis's Avatar
Monza, Italy
Joined Dec 2006
129 Posts
Xplorer airfoils ??

Hy guys,
Does anybody already get the Xplorer airfoils along its wing, ie root, middle, semitip, tips..... ??

I have got half-idea to reveal its airfoil by a couple of semi diaphragms for each section.
I would made them by a couple of mm plywood or plastic sheet pivoted in front of the LE, with a shape roughly larger than its section, and with a cream of microballons-aerosil-epoxi in direct contact with the surfaces wing's .
Off course the surfaces wing's will be prevently protected by PVC film.
During the cream curing, the diaphram will be held in position by a second ref pins aft the TE....

Then after curing, the cream should be sanded @ uniform thickness, the same as sheet thickness of the diaphragms ......

@ the end, to get the bitmap airfoils, I would employ a std scanner, while to get the .dat coordinate, Profili2Pro can be perfect....

What do you think about ??
Any suggestion alternative , more easy, quicker, and more precise, to reveal such airfoils from composite wings, will be very wellcome !!!!!!
So please don't hesitate to give me your suggestions & comments

I would compare few XFLR5 simulations with some measures on the Xplorer tacke by UniLog and its Speed Sensor...

Antonio.
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Old Jan 18, 2009, 08:57 AM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
21,352 Posts
I think that just maybe, the designer may not want the profile "revealed"....

Regards,
Target
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Old Jan 18, 2009, 09:26 AM
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andreis's Avatar
Monza, Italy
Joined Dec 2006
129 Posts
Quote:
Originally Posted by target
I think that just maybe, the designer may not want the profile "revealed"....

Regards,
Target
Target,
Accordinlgy with the manufacturer/designer desire/need, I doesn't have any intention to reveal their own secret .

I simply need to use them for my own purposes, like the comparison between the UniLog measures and XFLR5 simulation .

Antonio.
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Old Jan 18, 2009, 09:47 AM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
21,352 Posts
Sorry, I misunderstood what you were after....
However, just by asking if someone else had done what you want to do, it implies a sharing of proprietary information.
I've found that the more people know secret information, the less of a secret it becomes, and the better chance of it becoming public there is.

Please procede.

Regards,
Target
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Old Jan 18, 2009, 10:46 AM
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andreis's Avatar
Monza, Italy
Joined Dec 2006
129 Posts
Quote:
Originally Posted by target
Sorry, I misunderstood what you were after....
However, just by asking if someone else had done what you want to do, it implies a sharing of proprietary information.
I've found that the more people know secret information, the less of a secret it becomes, and the better chance of it becoming public there is.

Please procede.

Regards,
Target
Yes, unfortunately often happen what you mean ....
But...... especially when the infos are clearly declared by the owner to be maintened "reserved", I believe that it must be TOP respected !!

The time will slowly revel quite any secret..., but often or almost always when, no longer keep the secret, so we musn't do anything else that meet the time to be .

I'm a veery satisfied and affectionate NAN customer, so I'll continue to employ their product, but also use them as best as can I do, so deeply sguizing all that I can from their product .

All that I whant to share is the method to reveal unknow airfoils directly from wing already manufactured .

Please go forward with suggestions & comments on the proposed method.

Antonio.
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Old Jan 18, 2009, 11:02 AM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
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Your method sounds ideal to me, Antonio.

Target
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Old Jan 18, 2009, 11:19 AM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,749 Posts
When people are profiling the wings of their full-scale gliders, they do the same thing in reverse. Over time and heat exposure, the composite structure shrinks, and the airfoil contour suffers, as does the performance... They have templates made for every 12 to 18 inches and mix up a bit of epoxy/microbaloons. They lay a bead of this on the wing and allow the protected template to sit in it until it cures. They crack out the templates and fill/sand to that contour... YES... it DOES take a while! Don't ask me how I know.

I'll be building a large model with a proprietary airfoil soon, but it won't be in anyone's hands but my own for a while, so I can probably keep the coordinates secret fro as long as I want...

Jack
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Old Jan 18, 2009, 12:09 PM
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Joined Jul 2007
2,805 Posts
Quote:
Originally Posted by mlee8249
Hi Dave Webb,

You wanted to know my aileron differential rate, and it is 100% up and 32% down. My aileron to rudder mix for cruise, is 45%, thermal is 53%, reflex is zero, and launch is 75%.

Jack, you wanted to know about my towhook position. I am 1/8-inch ahead of the CG. With that, the rotation is pretty much instant, but the launch is almost hands-off.

Tuan....nice ballast set-up, dude! Wayyyy nice! (We are truly sick people when you find that drooling over a threaded slug of metal is normal for us).

Mike Lee

Mike, thank you for the information on your throws. If its not too much of a pain to take a micromiter to the field on your next day could you tell me the actual travel in MM on just the ailerons up/down? The percentage you are using is specific to your servo travel and your radio and I using a Stylus so it is less accurate to try for 32% down. Thank you in advance MIke.

DW
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Old Jan 18, 2009, 02:21 PM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
21,352 Posts
Quote:
Originally Posted by webbsolution
Mike, thank you for the information on your throws. If its not too much of a pain to take a micromiter to the field on your next day could you tell me the actual travel in MM on just the ailerons up/down? The percentage you are using is specific to your servo travel and your radio and I using a Stylus so it is less accurate to try for 32% down. Thank you in advance MIke.

DW
I was beginning to wonder if I was the only one thinking this...
Percentages mean nothing, unless they are of actual measurements. If the servo arm is offset differently, or the end points not set to the same angular degree, it means nothing.
I'm glad to know that somebody else caught this as well, I was starting to feel like a nerd (More like a nerd, that is.)

T
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Old Jan 18, 2009, 05:07 PM
Win=span\massXpractice+lu ck
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Quote:
Originally Posted by target
I was beginning to wonder if I was the only one thinking this...
Percentages mean nothing, unless they are of actual measurements. If the servo arm is offset differently, or the end points not set to the same angular degree, it means nothing.
I'm glad to know that somebody else caught this as well, I was starting to feel like a nerd (More like a nerd, that is.)

T


Dude, nerds are the new jock now. Nerds/geeks get the decent jobs, attract the hot girls who think smart is sexy and typically take advantage of the whole football team at the grad reunion because most of them are already too drunk to talk before dinner is served...easy pickings (if any of the girls you thought were cute are still cute that is)

Mike will inform us shortly of that I am sure.

I took the time in sun to get several flights off again....the differential settings are important but not as important as spotting that your aileron to flap coupling was moving in the wrong direction...doh Good thing it was only 20 % PAH!

Funy enough but the next couple of flights were way longer! Caught a 20 minute flight at 2 pm with ice still on the field....boooya!

I think I am going to go for a 106-107 CG I set it up for 108 but the plane is a bit twitchy.
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Old Jan 18, 2009, 05:13 PM
Detail Freak
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Harbor City, CA
Joined Oct 2003
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Thanks David, you made me laugh!

Good to hear you had a successful maiden and caught your programming mistake.
One of my buddies had somehow programmed some serious amount of snapflap in the flaps into his Ceres (like 3/4") on aileron throw.... His flies MUCH better now that we spotted THAT.

I'll make a note to start a little forward of the 108mm spot, thanks for the heads up.

Target
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Old Jan 18, 2009, 06:49 PM
RIP MC
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United States, CA, Midway City
Joined Dec 2003
3,198 Posts
Man, are we all that much alike here... Today I got some winch launches in and I was having a hard time flying smooth circles. Turns out I had 100% diff in that my ail only move up. I had accidentally programmed launch mode as my normal mode.

After getting that sorted out I, On my 4th launch I skied out and handed the tx over to a friend and he noted that the XPlorer was somewhat "twitchy", yep those exact words. I am at 107-108.

Anyway, he proceeded to sky it out even more and mentioned he might have just experience a 2.4g lockout, brought it straight down vertical with full crow, seemed like an eternity and by the time he got it down, seemed like a flap servo burned up (JR 3421).

I had to called it a day, but am thrilled at the flying characteristics even though only got in one decent flight.

Oh yea, I had not programmed in ele/crow compensation yet and he complained loudly about that. I am seriously thinking about going to 761.
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Old Jan 18, 2009, 07:00 PM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
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Hmmm, that's weird. The 3421 is just dead now?

T
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Old Jan 18, 2009, 07:02 PM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
7,749 Posts
Maiden!

I put mine up on an abbreviated high start today. Only got in one flight but it was 18 minutes from a 150' launch. This model slows much more than I'm used to so I stalled in from about 3' and stripped gears in the aileron servo... ...

Launch was straight up and hands off, (thanks Mike). I even got a good ping off the high start. It indicates lift about like my Houston Hawk... which is pretty good... ... and I have to say that it should come with a warning label... "Caution, flying this model may deepen your addiction to R/C Soaring!"

All-up weight for mine is 71.5 oz. It took .5 oz. to get her to balance at 108mm behind the leading edge. I need to tone down my control throws to some extent and add more down-elevator compensation to my crow. At that balance point, for me... it's just "twitchy" enough, so I won't be playing with that. I believe the stab and balance point were spot on when I got there. I have 1.5 degrees positive decalage, and she flew very well at that set up.

My antenna arrangement is inside the fuselage with 1/2 a length added and about 8" hanging out the base of the fin post. I did a full range check and was pleased with the result. Having specked her out on her maiden voyage has proven that set up to be OK.

OK... to be honest... it really flys like crap... don't waste your money... (Just kidding of course... I really just don't want anyone to know how much difference a GOOD model can make... ... It's all the pilot... yeah, that's the ticket!)

Se ya at SWC!!! (I sure hope I get some practice between now and then...)

Jack
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Old Jan 18, 2009, 07:14 PM
RIP MC
fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
3,198 Posts
Quote:
Originally Posted by target
Hmmm, that's weird. The 3421 is just dead now?

T
Well it just hums now and no response to movement of sticks. These were from a batch I bought I think 1.5 years ago. "Someone" told me there was a bad batch of them, but I don't know. I removed the covers to examine and they were very hot. I removed the other one and it was hot, but not as much. So no one assumes anything, there is no binding, but at max flap throws it is hard on the servos. I even "sanded" the hingeline to help loosen the flaps up a bit.

Will replace the one and see. To be fair, I had very close to 90 degrees of flaps and had not finalize my flap/crow yet, so there was stress on them servos for a good minute or so as he took that long to descended vertically with full flap thrown in.

Oh yeah, the RDS works perfectly. I love it. Now I will wait til I get me winch back from the installs of real balls and see if I can stress this thing out some. So far, it's solid.
Also, have I mentioned how linear the ail throws are , that's a good side benefit to RDS. And I don't have to mess with any servo connectors.
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