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Old Jul 10, 2009, 01:30 PM
In F3J size does matter!
roydor's Avatar
Israel
Joined Nov 2006
852 Posts
Mario,
What are the weights of your 3.5 and 3.8 Xplorers?
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Old Jul 10, 2009, 01:48 PM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
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Target,

Yes, the airfoils are different, but I regularly flew my full-scale at -8 degrees flap. Cruising at 60 knots with 0 flap, and just going to -8 flap would add 20 knots to the airspeed, with no other trim changes. So, 6 degrees of reflex may cause the conventional wisdom crowd to wonder, but, it sure seems to help my model... Nothing ventured, nothing gained...

Try it... you'll like it...

Jack
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Old Jul 10, 2009, 01:51 PM
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Boca Raton, FL
Joined Apr 2009
107 Posts
Thanks for the prompt responses!
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Old Jul 10, 2009, 02:00 PM
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Encinitas, CA
Joined Jun 2007
176 Posts
I have no idea what the weight on these gliders are. I will check and let you know. What I have noticed is that I LOVE the way the 3.8 meter flies. It just floats FOREVER. I have flown it both with high start and winch in up to say 7-8mph wind. It is a bit, just a bit harder to land than the smaller version but if you are experience landing this thing is NO PROBLEM.
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Old Jul 10, 2009, 02:18 PM
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Joined Jan 2004
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"QUOTE :Also to get the max lift on launch(or very close to it) fly your X in launch mode and adjust elevator so it flies at minimum sink. My elevator adjusts also depending on the amount of launch camber I put in. "

Tuan,
This is good if you are launching at the same speed you are setting your elev.
Launch speed is much faster than min sink speed.
sj
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Old Jul 10, 2009, 02:59 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
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I just really don't think it's fair for you guys to have multiple Xplorers... WAH!!!

My boat is going up for sale so I may have one coming soon...;D

Jack
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Old Jul 10, 2009, 03:15 PM
RIP MC
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United States, CA, Midway City
Joined Dec 2003
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Quote:
Originally Posted by SmokinJoe101
"QUOTE :Also to get the max lift on launch(or very close to it) fly your X in launch mode and adjust elevator so it flies at minimum sink. My elevator adjusts also depending on the amount of launch camber I put in. "

Tuan,
This is good if you are launching at the same speed you are setting your elev.
Launch speed is much faster than min sink speed.
sj
This is just to get it trimmed out while in launch mode. Without initial settings how would one know where that elevator needs to be with say 15 degrees of flaps? I've tried a lot of different settings and methods now and this works oh so good.

The reason to go slow up on line is that the faster you go, the higher the percentage drag of not only the model but the line as well. You get all the speed you want the last second in the dip.

Don;lt think I can get out to fly this weekend. Building points for next couple weekends.
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Old Jul 10, 2009, 03:46 PM
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Joined Jan 2004
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Quote:
Originally Posted by fnnwizard
Don;lt think I can get out to fly this weekend. Building points for next couple weekends.
Your assuming the wife knows how to count and your points are valued the same as the wife values points

sj

who looks like he's going to fly Sunday any one up for Dollar landings?
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Old Jul 11, 2009, 08:33 AM
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Pontoise Vexin, France
Joined Jun 2004
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Quote:
Originally Posted by fnnwizard
Oooh, I forgot to mention, I had a chance to go down to my local park (1 block away) where I did some hand lauching to dial in my crow. Park is way to small for even a histart. It was quite windy yesterday (12-17mph) so I played with the reflex setting just using hand tossing. I found penetration to be decent with reflex at a whopping 4mm without any ballast. but at ground level it was turbulent so take this setting with a grain of salt.

The amount of reflex did seem too much to me until I came home and, using the "ruler's edge along the bottom of the wing found 4.5mm to be "flat against the straight edge"... so now this will become my zoom reflex. It was at 3mm before. I will now use 4.5-5mm and see what it does.

I wish Nan can post a theoretical analysis of the airfoil like Samba does with the Pike Perfect.
Sounds like this is too much reflex to me, even if i also find that the xplorer need more reflex than other gliders for the best transitions against the wind.
Here is my approach to find the best setting: to make a analogy with cars, elevator is the accelerator and camber is the gearbox. So i set the elevator first by searching the best "transition trim" for a given flap camber. Then, i try to find another setting with different camber. Then, i choose the best flap/elevator setting.
That's a long tuning where i think, elevator trim is more important (and more tricky) than flap setting. All of this considering that the plane is well ballasted for the wind. How much ballast ? Another big subject, that also d epend on your best transition flap/elevator setting !!


Loc
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Old Jul 13, 2009, 02:01 AM
RIP MC
fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
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Ok, I went out today and did some launches with the zoom in reflex of 4.0mm-5.5mm (there's play in the flaps so no idea how exact the measurement is but minimum is 4mm max is 5.5mm) All downwind launches today so harder to compare from baseline, but it seems to carry better in the zoom.

Also I noticed there is less tendency to over rotate, but it could be due to downwind launches.

From what I have read to be preferable, one would want zero lift in the zoom if one was to zoom vertically. I guess it also goes that if one were not in a vertical state, then one would want some lift in the wings, for example, for a 45 degree zoom. I'm purely speculating here as I have no basis for any aerodynamic theories.

I would love for any experts to comment.

Tonight I took the center panel from a Pike Perfect and an Xplorer and traced the airfoil at the joiner end. The Xplorer airfoil is about 1mm thicker toward the bottom of the airfoil, 30mm from the LE. To me, it looks to have more camber (at least in this section). It does have larger chord and flaps.

The original zoom settings on the Perfect recommend 3mm reflex, so to me it certainly looks about right with the Xplorer having 4mm given the larger chord and additional camber.

I am waiting on the software Profili Pro to do some airfoil comparisons.
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Old Jul 13, 2009, 09:33 AM
RIP MC
fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
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Think we need to start a new Xplorer thread with just building flying tips? This one is gettting long...

Anyway, I made a new template to help get my flap throws more aligned. Havent used it yet, but it basically goes in between the center panel and each tips. You'll need to print it on some 8x11 card stock.
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Old Jul 13, 2009, 10:37 AM
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S. FL
Joined Jan 2007
854 Posts
Quote:
Originally Posted by fnnwizard
Ok, I went out today and did some launches with the zoom in reflex of 4.0mm-5.5mm (there's play in the flaps so no idea how exact the measurement is but minimum is 4mm max is 5.5mm) All downwind launches today so harder to compare from baseline, but it seems to carry better in the zoom.

Also I noticed there is less tendency to over rotate, but it could be due to downwind launches.

From what I have read to be preferable, one would want zero lift in the zoom if one was to zoom vertically. I guess it also goes that if one were not in a vertical state, then one would want some lift in the wings, for example, for a 45 degree zoom. I'm purely speculating here as I have no basis for any aerodynamic theories.

I would love for any experts to comment.

Tonight I took the center panel from a Pike Perfect and an Xplorer and traced the airfoil at the joiner end. The Xplorer airfoil is about 1mm thicker toward the bottom of the airfoil, 30mm from the LE. To me, it looks to have more camber (at least in this section). It does have larger chord and flaps.

The original zoom settings on the Perfect recommend 3mm reflex, so to me it certainly looks about right with the Xplorer having 4mm given the larger chord and additional camber.

I am waiting on the software Profili Pro to do some airfoil comparisons.
From your trace of both airfoils I get roughly ;
Pike= 8.9% thick, 2% camber @ 26% cord
Xplorer= 9% thick, 1.8% camber @ 22.5 cord
I used a straight edge and mm measurments. I hope they are close
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Old Jul 13, 2009, 11:07 AM
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fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
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Quote:
Originally Posted by Libelle201B
From your trace of both airfoils I get roughly ;
Pike= 8.9% thick, 2% camber @ 26% cord
Xplorer= 9% thick, 1.8% camber @ 22.5 cord
I used a straight edge and mm measurments. I hope they are close
Wow Libelle, thanks for the info. I would have bet good money that the X had more camber, or at least under-camber, sure looks that way from the tracing.

Noticed the X airfoil near the flap curves up above the centerline. Also if I lay a straight edge under the wing the X flaps deflect up ~4.25mm to lay flat with the ruler while the Perfect is about 3mm. I'm trying to learn this new to me stuff and appreciate all comments.
Here's a better picture
T
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Old Jul 13, 2009, 01:08 PM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
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There's a good chance that both of these foils are much different at both the tips and the roots of the center panel....

Just a heads up.

T
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Old Jul 13, 2009, 01:14 PM
RIP MC
fnnwizard's Avatar
United States, CA, Midway City
Joined Dec 2003
3,281 Posts
Quote:
Originally Posted by target
There's a good chance that both of these foils are much different at both the tips and the roots of the center panel....

Just a heads up.

T
For sure the Pike is different, Pk, gives 5 sections for analysis.

Don't know about the X. I just used the center section of each to give a reason that 4.5mm reflex seems reasonable. Ya missed some of the action yesterday .

Ok, I'm off to the garage!
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