Espritmodel.com Telemetry Radio
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Old Jul 10, 2012, 07:40 AM
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Vivab44,

I had a nose dive happen to me. The battery had slid forward in flight. I repaired and added Velcro to the battery and no problems since. The design allows the battery to slide after the foam has loosened.
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Old Jul 10, 2012, 09:07 AM
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The reason that manufacturers do not use separate BECs is partly economic. Using a combined ESC/BEC means one less component to install. It is also unnecessary if good quality ESCs are used. I build my Radians from replacement parts and use inexpensive but reliable Turnigy ESCs with on-board BECs. I don't know if there is a Spectrum issue but I use Futaba 2.4 GHz gear. Never had a problem I thought was caused by brownout or loss of signal.
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Old Jul 10, 2012, 09:50 AM
Bring It On !!!!!
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Newmarket, England.
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Quote:
Originally Posted by aeajr;


EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC POWERED FLIGHT
[url
http://www.wattflyer.com/forums/showthread.php?t=31368[/url]
http://www.rcuniverse.com/forum/m_7100376/tm.htm
That's just perfect AEAJR well done.

I like the way you didn't big yourself up and say "Here's what I wrote" You should do though it's just what we needed.

Excellent
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Old Jul 10, 2012, 11:58 AM
Tossing planes into the snow
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I think I've got this plane trimmed out pretty well, if being able to fly hands-free is a criterion of success. It's amazing how long it will go without any input. I'm sure it would come to a fairly respectable landing all by itself. I flew it stock a few times, and then added about 8 grams of mods to stiffen the tail. On top of that, I still had to add 5 grams of dead weight back there to get it to fly with a neutral elevator. The CG is about 10mm back of the factory spec.

So here's a loaded question...If I did the infamous mod, would it still fly by itself, or would it require more input from me?
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Old Jul 10, 2012, 12:40 PM
Zor
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Originally Posted by Jovanx View Post
I think I've got this plane trimmed out pretty well, if being able to fly hands-free is a criterion of success. It's amazing how long it will go without any input. I'm sure it would come to a fairly respectable landing all by itself. I flew it stock a few times, and then added about 8 grams of mods to stiffen the tail. On top of that, I still had to add 5 grams of dead weight back there to get it to fly with a neutral elevator. The CG is about 10mm back of the factory spec.

So here's a loaded question...If I did the infamous mod, would it still fly by itself, or would it require more input from me?
It likely would glide on its own after using some trim.
Elevator not in the same flat plane vs the stab.

The rate of decent would also be increased.

The lowest rate of descent occur near the best Lift to drag ratio at a wing angle of attacj just about 3 to 4 degress. This corresponds (results) at a specific gliding speed.

My Radian pro was measured at 3.8 degrees of decalage.
Designers tyically use these figures to optimize the design.
The Radian is likely close to that.

Removing this decalage results in trim requirement out of neutral.

Winning a contest reflects on the pilot abilities and the local atmospheric conditions (thermals) at the time of the contest. It does not reflect on the removal of the decalage angle.

Zor
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Old Jul 10, 2012, 12:43 PM
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Originally Posted by Jovanx View Post
So here's a loaded question...If I did the infamous mod, would it still fly by itself, or would it require more input from me?
After the mod mine flew as slowly and with the same low sink rate as before, which is to be expected because after adjusting the cg rearward and trimming it should be flying at the same Angle of Attack as the unmodified plane. The difference is that it will have less pitch stability. That will make it respond more quickly to AoA changes caused by thermals and gusts. In calm air it will fly much as before but in turbulence it may require more control input.
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Old Jul 10, 2012, 01:05 PM
Zor
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Originally Posted by kaptondave View Post
After the mod mine flew as slowly and with the same low sink rate as before, which is to be expected because after adjusting the cg rearward and trimming it should be flying at the same Angle of Attack as the unmodified plane.
It is difficult to judge the flying speed and sink rate.
I have to assume that you have an opinion to back up justification of the modification.

Quote:
The difference is that it will have less pitch stability. That will make it respond more quickly to AoA changes caused by thermals and gusts. In calm air it will fly much as before but in turbulence it may require more control input.
Which of the three types of stability are you thinking of ?
More control input is always needed in turbulence.
Stability is a slow responding process thus the need for more input control in turbulence.

It would be interesting to understand why the modification causes less pitch stability (if it does).

Zor
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Old Jul 10, 2012, 01:26 PM
Tossing planes into the snow
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Originally Posted by Zor View Post
It would be interesting to understand why the modification causes less pitch stability (if it does).
Throwing aside all theories about aerodynamics for a minute (I prefer to think of them as theories rather than facts), here is the obvious question...

Why is it that everybody who has done the infamous mod has been pleased with the results? (including Paul who wins contests using that mod...we know he is a skilled pilot, yet he still does it).
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Old Jul 10, 2012, 01:47 PM
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Old Jul 10, 2012, 02:04 PM
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I modified my Radian and the Radian Pro to 0* decalage as I do with almost all gliders I own. I reworked my Easy Glider Pro to a floating tail to eliminate the argument all together. In all cases I also move my CG as far back as I like to fly at. In dead air all modified gliders can fly dead slow, slower then originally did mostly due to rearward shift in cg. The huge difference is that now the glider does not plow through the air over stabilized, it feels much more nimble, reacting to air currents and signaling lift. Also when hitting turbulent air it rises up and down fairly level not just nosing up and down creating the usual up down oscillations of a nose heavy machine with every change of speed. Of course full power climb is just a strait line holding tiny bit up in my case.
As a side note I modified several of these foamies and I stiffen the fuse first and then measure the decalage, each one proved to be a little different angle. It is better to leave a bit of a positive angle rather then go to far which creates a bit unpleasant flying glider.
One of my friends has unmodified Radian but very rearward CG, in dead air, side by side, his sink rate and speed is comparable with our modified ones, but it does not signal air changes as well and once upset by gusts, his corrections are much more difficult then ours, due to instant humping up and down and as a result he always losses more height then we do. It all also depend on flying experience, few years ago I did not see or feel much of this, but now I do and I know what I am looking for, but still learning every day.
By the way my fully floating tail on my EGP, after I got it to fly to my liking and measured the decalage angle it is nearly 0 and so is my newly motorized Aguila Woodie gas bag.



Quote:
Originally Posted by Zor View Post
It is difficult to judge the flying speed and sink rate.
I have to assume that you have an opinion to back up justification of the modification.



Which of the three types of stability are you thinking of ?
More control input is always needed in turbulence.
Stability is a slow responding process thus the need for more input control in turbulence.

It would be interesting to understand why the modification causes less pitch stability (if it does).

Zor
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Old Jul 10, 2012, 02:12 PM
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Originally Posted by Zor View Post

Removing this decalage results in trim requirement out of neutral.

Zor
Not quite, Zor. It's the other way round. If you remember Paul suggested the decalage mod be done because he moved his CG farther to the rear. If you do that you will find that the Radian then requires trim compensation to counter the forces induced by the excessive decalage angle which were required to compensate for the excessive nose heaviness of the Radian and allow the bird to fly with a neutral elevator. Reducing the decalage angle after moving the CG back will then eliminate the out-of-trim condition and allow the elevator to be brought back to the neutral position.

If you don't move the CG back, you want to leave decalage alone.

Cliff

PS to any Noobie reading this. If you elect not to do any major surgery on you bird at least try moving the CG back a half inch or so in baby steps. You will be very pleased with the result.
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Old Jul 10, 2012, 02:17 PM
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Old Jul 10, 2012, 02:54 PM
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Originally Posted by Radio.Active View Post
As I recall, you mentioned that your Radian already had a reduce decalage out-of-the-box because of that stupid PKZ composite non-glued stiffener.

I've found that when I add my CF arrows I don't need to do the decalage mod as the tail boom is vertically straight on the bottom, the elevator is pulled down and the decalage is then near zero.
Thank you for confirming what I was suspecting. The fiberglass "stiffener" that comes out weighs about 12 grams with glue, and it is not straight. It is curved so that when in position, the ends are bent up higher than the middle to conform with the curved underside of the fuselage.

The benefits of replacing the existing FG junk with a CF arrow shaft are a whole other story, just in terms of the increased control you get from the elevator and rudder, but here we also have a decalage adjustment. When I put that straight rod into that curved slot, the ends were still sticking out. I wrapped some tape around the ends of the rod to hold them while the glue was setting up. The decalage was reduced by forcing the fuselage into another position. It flies great!!
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Old Jul 10, 2012, 04:12 PM
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Originally Posted by Jovanx View Post
Throwing aside all theories about aerodynamics for a minute (I prefer to think of them as theories rather than facts), here is the obvious question...

Why is it that everybody who has done the infamous mod has been pleased with the results? (including Paul who wins contests using that mod...we know he is a skilled pilot, yet he still does it).
The other question is: Why is it that the ONLY person that incessantly rails against the mod it the one who has never done it, never even seen a modified Radian, and knows absolutely nothing about it? This person keeps repeating the same tired argument that the modified plane flies faster and has a higher sink rate, neither of which is true.

Those that have done it are pleased because it flies better, which is the reason Paul advocates it and the reason he wins contests with it.
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Old Jul 10, 2012, 04:48 PM
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Naked-Eye Flying, my Parkzone Radian

Parkzone Radian New World Record High Altitude Flight (21 min 55 sec)
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