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Old Feb 26, 2011, 08:03 AM
Rocket geek
Highlands Ranch, CO
Joined Dec 2007
651 Posts
Quote:
Originally Posted by kingsflyer View Post
Be sure you recheck your CG before you fly it that way. You have added some weight a long way behind the CG.

McD
Indeed, I have to bring the battery all the way out of the compartment to get 72mm CG. I think there's one more mod I need to make before the maiden, and that is to install some Velcro along the side of the forward compartment for the battery.
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Old Feb 26, 2011, 08:38 AM
Addicted to flight since 1944
rbrown3rd's Avatar
southern Florida
Joined Feb 2004
1,750 Posts
Quote:
Originally Posted by aeajr View Post
Note that wearing your pants low does not help with landing accuracy.
I am just not coordinated enough for competition sailplane flying. I can't keep my pants up just under my butt and fly at the same time.
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Old Feb 26, 2011, 10:22 AM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
Quote:
Originally Posted by Adrian A View Post


It's facing forward, but I stuck it on the top of the fixed part of the stabilizer. Seemed like the spot least likely to snag on anything. I need to post a picture. The silicon pressure tubes run all the way back to the sensor that I jammed behind the servos. I bought it for an Eagle Tree Elogger, but the first one I got was defective and I'm not really willing to wait for the replacement before the maiden. Eventually I'll have a ridiculous amount of data to share, though.
At the rear of the plane your data will not be so clean because of the turbulence generated by the plane. That's why the pitot tube is normally on the leading edge a little more than a prop radius out from the fuselage (for a propped plane), or in the nose for a pure glider.
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Old Feb 26, 2011, 10:23 AM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
Quote:
Originally Posted by aeajr View Post
Can it spot land well? Compare to what? Define the spot.

Do you mean a 100" AMA tape, spot landing for score? Or do you mean in a 10 foot circle?


I can put that Radian in a 10 foot circle pretty consistently and a 100" tape sometimes. I am sure I could land the Pro on a 100" contest tape using the flaps with a little practice.




Flying gliders is all about energy management. As you get better at it you can spot land these planes in a pretty small area with high consistency. But you have to practice and what you are practicing is energy management.

What is my approach speed?

Should I go around to lose altitude or should I come straight in?

When to I touch to slide into the spot. The ground makes a pretty good breaking system as the plane slides in.

When do I apply flaps? How much?

What is my best approach altitude? Should I come in steep or should I come in shallow?

Practice, practice, practice. That is how the power pilot learn to land their planes and that is how glider pilots learn to land their planes too.


THIS IS SPOT LANDING AND YES, YOU CAN DO THIS WITH A RADIAN PRO
No, you don't have to dork the nose into the ground silly!

Landing Practice – These guys are among the best in the world and they practice all the time. This is how you get good! Note that these guys tape their practice, probably so they can review and learn from what they did, to get even better.

If you want to be able to spot land your glider, you need to practice.

Expert and World Champion Daryl Perkins
http://www.youtube.com/watch?v=-7411...layer_embedded

World Class competitor Brendon Beardsley
http://www.youtube.com/watch?v=jy7yo...eature=related


Note that wearing your pants low does not help with landing accuracy.
Also note that they are not flying in a tight field. The pros know better.

It looks like they tend to use a very shallow approach slope and only use flaps/spoilers right at the end.
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Last edited by JumpySticks; Feb 26, 2011 at 10:39 AM.
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Old Feb 26, 2011, 11:40 AM
No risk, no fun
Siggy101's Avatar
Switzerland, VD, Chéserex
Joined Jan 2011
242 Posts
Back to Radian Pros for a few minutes lads...

OK, I just got out for an hour or so's flying with the RP today.
Only my second outing with a sailplane and somewhat more tricky this time...

There was a fair bit more wind today , I have no anenometer so can't say what speed, so things were more.... interesting.

First off, those of you who saw my maiden videos will know that my cg was too far back resulting in mild porpoising. I have since moved the battery forwards and am at the recommended cg now. This flight felt really odd in that the slight porpoising was a lot worse as if the cg had moved backwards. Mighty odd as I know it is spot on now.
As soon as I picked up any more speed than stalling the plane porpoised upwards and wanted to stall again. I found that she wanted to drop a wing very easily and controls were generally not nearly so responsive (maybe caused by the low speed because of the porpoising?). Can anyone help at all? I'm confused.
I did find that she did not want to raise the nose quite so much under power so that was an improvement.

I was flying in the same spot as the maiden but there was a light breeze blowing up the hill today. I was still able to see loads of large birds thermalling in the same place as I caught that winner thermal on the maiden so I guess it is a regular occurence. Note for the future! Today the thermals seemed to be breaking off as bubbles as I could see all the birds staying inside a clearly defined 'sphere'.

I was very hesitant to land today due to the lack of stability/control but when I did, all went perfectly well and no wing catches at all, most satisfying.
I did find that a bit of wet mud was left on the bottom of the fuse so decided not to land on the ground anymore. Seems yucky

So I dedicated the rest of the session to practicing hand catches. I just kept throwing, flying a circuit and then catching again. The plane did not touch the ground for the rest of the session and I think I counted over a dozen catches in all. I did have to relight the motor and go around on about 4 or 5 of them so not quite perfect yet.
I was playing with flaps vs crow. I found the need to vary between the 2 depending on headwind velocity and approach speed/attitude but by the end I felt perfectly comfortable with either flying the plane into my hand in a climb up from waist height or allowing it to stall into my hand over my head and catching under the belly.
I found a nice method in keeping the plane aimed straight at my head (ie: I couldn't see the fuselage) on approach then drop down below waist height to track along level for about 20m to assess approach speed followed by a flare about 5m out. I was using a mix of crow/flaps on the initial descent and the flare. I often found it better to retract all flaps/crow on the 'low tracking' especially if airspeed was a little low.
I have no idea if what I'm doing is right but it seems to work for me as I didn't have a single botched catch. I did see that I was clearly short on some approaches and chose to relight and go around in plenty of time.

All in all, I am very pleased indeed with the catching progress. I am looking at building a DLG next so need to master hand catches pretty sharpish.

I am slightly purturbed by the odd porpoising as I expected the opposite. I was expecting it to feel nose heavy but that was not the case. Anyone care to enlighten me as to what went on there?
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Old Feb 26, 2011, 12:10 PM
Rocket geek
Highlands Ranch, CO
Joined Dec 2007
651 Posts
Here's my pitot tube installation:



I used a soldering iron to melt a channel for the tubes, and then used Gorilla glue to fill it in. They're reasonably flush, but I'm planning to cover the tail sometime which will make it prettier.



I wanted to make sure that it was located somewhere where it wouldn't interfere with hand catches, it had reasonably clean airflow, and didn't add any difficulty to installing the wings. That's about the only spot that meets that criteria. It is a little extra mass in the wrong spot, though. I think I would have to have a severe angle of attack for the flow there to be affected by the rest of the plane. More discussion of tail-mounted pitot tubes on full size aircraft:

http://www.homebuiltairplanes.com/fo...mesis-nxt.html
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Old Feb 26, 2011, 01:30 PM
Registered User
Phoenix, Arizona
Joined Apr 2009
256 Posts
Radian Pro Simulation

For all you Radian Pro wannabes, here is a fairly decent simulation you can fly on your PC. http://www.rcdeskpilot.com/node/4137
BTW, the download also includes a sim of the original Radian.
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Old Feb 26, 2011, 01:38 PM
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KDunk's Avatar
Joined Jan 2011
32 Posts
Porpoising and CG
I am having the same issues. To get the GC into range I had to move the batt so for forward it's touching the ESC. CG is now perfect but I'm still having trouble with the porpoising. Also when I climb out at 3/4 power I have to keep pushing the nose down to keep it from going vertical, stalling and droping a wing.
My only thought is that the porpoising seems to be worse the higher I am so I wonder if it's because I can't see the plane as well and making sloppy inputs.

Siggy101 have you decided on a DLG Model?
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Old Feb 26, 2011, 01:49 PM
Registered User
Phoenix, Arizona
Joined Apr 2009
256 Posts
Quote:
Originally Posted by Siggy101 View Post
,,,I am slightly purturbed by the odd porpoising as I expected the opposite. I was expecting it to feel nose heavy but that was not the case. Anyone care to enlighten me as to what went on there?
Porposing is often a symptom of too much up elevator trim (to compensate for a nose heavy condition). Try setting your elevator dead level with the horizontal stab and toss the PRO straight out on a windless day. If it tends to dive, move the CG back until you get a perfect (long) glide.
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Old Feb 26, 2011, 01:57 PM
Registered User
Phoenix, Arizona
Joined Apr 2009
256 Posts
Quote:
Originally Posted by KDunk View Post
Porpoising and CG
I am having the same issues. To get the GC into range I had to move the batt so for forward it's touching the ESC. CG is now perfect but I'm still having trouble with the porpoising. Also when I climb out at 3/4 power I have to keep pushing the nose down to keep it from going vertical, stalling and droping a wing.
My only thought is that the porpoising seems to be worse the higher I am so I wonder if it's because I can't see the plane as well and making sloppy inputs.

Siggy101 have you decided on a DLG Model?
Sounds to me as if the motor has too little down thrust. This can easily happen if you had a "lawn dart" experience that compressed the nose. On the PRO, this generally results in tipping up the nose (ask me how I know). If your canopy no longer fits perfectly, you probably should do the hot water treatment (after removing the motor and ESC, of course).
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Old Feb 26, 2011, 08:33 PM
too cheap to be a Plus user
dougbo's Avatar
USA, WA, Richland
Joined Nov 2009
1,260 Posts
Couldn't wait any longer ... Radian Pro maiden today. Temperature around 31F & winds blowing 10 - 20mph. Fun flights with hovering landings. The Radian Pro is a fun piece of foam.

Doug B.
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Old Feb 26, 2011, 08:56 PM
too cheap to be a Plus user
dougbo's Avatar
USA, WA, Richland
Joined Nov 2009
1,260 Posts
Quote:
Originally Posted by jchunter View Post
Porposing is often a symptom of too much up elevator trim (to compensate for a nose heavy condition). Try setting your elevator dead level with the horizontal stab and toss the PRO straight out on a windless day. If it tends to dive, move the CG back until you get a perfect (long) glide.

Thanks for the tip. I set my CG to the manual specification however I have a touch of up elevator which is probably causing a mild porpoise. The wind was very gusty today so I wasn't sure if the elevator trim was an issue. I'll remove the up trim & test fly it on a calm day.

Doug B.
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Old Feb 26, 2011, 10:15 PM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
I was hoping for another "Big Sky" thermal attempt today, but the wind came up, contrary to forecast.

So I took her out to the levee and gave slopin' a try. As expected, the trees paralleling the levee did not provide a slope effect on the levee itself, but I did get a few 5 minute near hovering flights over the tree line. Winds were SW about 15 gusting to 20 out there. There was a good wave of lift at about twice tree height, and that's where I spent most of the flights. I tried getting up some speed running parallel to the tree line in order to build up some dynamic momentum, but the trees being of differing heights made the wave very unpredictable. The plane would get real squirrelly passing through such turbulence.

Futher, I could not make dynamic turns into the wind because of the tree/canal problem, so I settled for drifting back and forth, near hovering(some negative groundspeed on the gps plots), in a couple of spots where the wave was consistent . As discussed before, on the other side of the trees is a canal, where I did not want the plane to end up, so I was somewhat cautious. Especially being that this was my first slope flying ever.

Once I would get too far on the lee side of the trees, over the levee or behind the levee, the winds became very turbulent...as in rotors, where the plane would drop or roll violently and I would have to add power to recover. For that reason I could not land safely without power, and so...no "Big Sky" flights to report (Sorry AEAJR).

Landing on the levee was not easy. It's a 25 degree slope, not much less than the glide slope of the plane with flaps. I ended up with full flaps struggling to get her on the ground safely. No way to land on the back side of the levee or the trees due to the strong rotors.
2 KMZ files attached, but it's a lot of spaghetti in a small area.
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Last edited by JumpySticks; Feb 26, 2011 at 10:28 PM.
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Old Feb 27, 2011, 07:13 AM
Heli's and gliders, what else?
BarnOwl's Avatar
Nederland, GE, Slijk-Ewijk
Joined Apr 2006
747 Posts
Quote:
Originally Posted by Adrian A View Post
The aileron linkage is both tall and long. I used the F18 servo covers from a few pages back. There's a place that makes lots of blow-molded servo covers.
http://www.morganmill.com/RC/rc-site-10-7-08_024.htm

When I got them I thought they were oversized, but I think they may be the only ones they have that aren't too small.
I purchased these covers as I could not find another adress that makes them....
How did you stick them to the wings? Did you use ca or double-sided tape?
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Old Feb 27, 2011, 07:44 AM
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1911tex's Avatar
Joined Nov 2010
287 Posts
I used the same servo covers (#17).......used Gorilla white. Perfect.
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