HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old May 07, 2012, 12:58 PM
Tossing planes into the snow
Canada, BC, Smithers
Joined Nov 2011
2,939 Posts
Quote:
Originally Posted by kaptondave View Post
It is easier now to maintain slow gliding flight with minimum sink.
Does this also translate into slower landing speeds, possibly making it easier to hand-catch? How about wind-penetration...does the decrease in overall drag help it to go fast as well as slow?

I tried removing the 3 screws to see if the plastic parts were glued on and they are. How do you pry them apart without ripping the foam?
Jovanx is offline Find More Posts by Jovanx
Reply With Quote
Sign up now
to remove ads between posts
Old May 07, 2012, 01:21 PM
Closed Account
Joined Aug 2011
530 Posts
...
Radio.Active is offline Find More Posts by Radio.Active
Last edited by Radio.Active; Jun 13, 2013 at 06:46 PM.
Reply With Quote
Old May 07, 2012, 04:08 PM
Not a newbie anymore..
skyhawk newbie's Avatar
Ireland, Cork
Joined Oct 2010
2,027 Posts
Quote:
Originally Posted by Jovanx View Post
Can you tell me more about this system? I am thinking of getting a Futaba 7c, and would like to be able to fly my Parkzone planes with it as well. Does the module let you simply switch back and forth from Futaba to Spektrum receivers?
To be honest I don't know if you can swap modules back and forth..

Maybe you can ,
I had AR500 Rx's in a few of my gliders and had 2 DX5e,
But as I bought more glider I didn't want to buy any more Tx's and didn't want to re-bind evey time I swapped what I was flying....
Bought the Futaba 9c off E-Bay cheaper then a DX8
then bought the Spektrum module(futaba compatable) with a AR800 rx..

Sean.

.
skyhawk newbie is offline Find More Posts by skyhawk newbie
Reply With Quote
Old May 07, 2012, 04:14 PM
Not a newbie anymore..
skyhawk newbie's Avatar
Ireland, Cork
Joined Oct 2010
2,027 Posts
Quote:
Originally Posted by kaptondave View Post
I too have done the Paul Naton decalage mod and find it very satisfying. It is easier now to maintain slow gliding flight with minimum sink. My CG is at 83 mm, 20 mm back from the stock value. The rearward CG combined with neutral decalage has made the ship more sensitive to changes in lift caused by thermals, but along with that comes decreased stability, which I believe is the reason some say it is not for everybody. It is not dangerously unstable by any means but less experienced pilots need to stay on top of things to avoid a possible stall when an updraft is encountered.
Hi Dave
I'm glad your here ...

Dave is one of the Guru's on the Decalage Mod

I think after doing the decalage mod ,
you can see the wing react more when you hit a thermal
..
skyhawk newbie is offline Find More Posts by skyhawk newbie
Reply With Quote
Old May 07, 2012, 09:16 PM
Registered User
Joined Jan 2010
3,491 Posts
Quote:
Originally Posted by Jovanx View Post
Does this also translate into slower landing speeds, possibly making it easier to hand-catch? How about wind-penetration...does the decrease in overall drag help it to go fast as well as slow?
It glides smoothly at low speed but there is an increased risk of stalling because you are working closer to the edge of the stability envelope. I don't do wind very much but for optimum penetration I think you would want to shift the cg forward, perhaps by going with a larger battery. Again you might find it more easily upset by gusts. Overall I think the mod is better suited to light wind but do not have enough wind experience to know for sure.


Quote:
I tried removing the 3 screws to see if the plastic parts were glued on and they are. How do you pry them apart without ripping the foam?
Mine did not have a lot of goop so came off easily.
kaptondave is online now Find More Posts by kaptondave
Reply With Quote
Old May 08, 2012, 08:38 AM
More Altitude, Less Attitude!
chickenwing's Avatar
United States, SC, Ninety Six
Joined Mar 2008
547 Posts
Quote:
Originally Posted by skyhawk newbie View Post
I think after doing the decalage mod ,
you can see the wing react more when you hit a thermal
..
This is true. There is also a more pronounced reaction of the tailplane when passing through a thermal. Last outing, I was cruising along when suddenly, the tail was yanked straight up! I have also observed that I can make tighter, flatter turns in the core. It's a beautiful thing to watch the Radian get higher and higher with every turn.
chickenwing is offline Find More Posts by chickenwing
Reply With Quote
Old May 08, 2012, 11:42 AM
Closed Account
Joined Aug 2011
530 Posts
...
Radio.Active is offline Find More Posts by Radio.Active
Last edited by Radio.Active; Jun 13, 2013 at 06:46 PM.
Reply With Quote
Old May 08, 2012, 12:13 PM
Tossing planes into the snow
Canada, BC, Smithers
Joined Nov 2011
2,939 Posts
Hi Alan
Here is a picture showing the relative wall-thickness of 3 tubes. The one on the left is the stock fiberglass spar from the Radian Pro. The one in the middle is the CF shaft I am using now, and the one on the right is an arrow shaft. Even though the arrow shaft has much thinner walls, it is still a bit stiffer than the stock FG rod. It would probably be the ideal solution for someone who wanted the plane to be as light as possible for competition thermaling.

My aim was to get rid of the wing flex, and the one in the middle works better than you can imagine. It is WAY stiffer than the stock one, and still 13 grams lighter. No more flapping wings for me. It can crank super tight loops and turns and the best part is the aileron response is more positive. Although that doesn't apply to the Radian, the stiffer wings will still make it fly better.

After watching a video of my plane cranking a bunch of tight loops, Jumpysticks decided to put an arrow shaft in his because he couldn't find a thick-walled CF tube. As expected, it only made a marginal difference to the wing flex. Then he got another arrow shaft and put it inside the first one, and that did it. He was so excited about how well it flew, and so am I.
Jovanx is offline Find More Posts by Jovanx
Reply With Quote
Old May 08, 2012, 12:47 PM
Not a newbie anymore..
skyhawk newbie's Avatar
Ireland, Cork
Joined Oct 2010
2,027 Posts
Quote:
Originally Posted by Radio.Active View Post
Okay FWIW. here's an image dumpster of all my Radian mods

https://skydrive.live.com/?cid=DBDE7...65DDCB92%21672

The image names sort of describe the point of the picture.

Some mods are common to the 2 Radians I have left - Gold N Rods, CF arrow replacing the factory installed boom stiffener, Dubro hinges everywhere except on the factory HStab, CF rod in VStab, Futaba and Orange RX in the cockpit.

Other mods randomly appear on the 2 fuselages.

The DIY HStab is 3/32 balsa with UltraKote top and bottom and Dubro hinges and is rigid enough to not need CF reinforcement.

The DVS130M Parkzone digital metal gear servos are from the wings of a deceased Radian Pro ( same physical size as OEM PKZ servos) and require 50% End Point programming.

One has the decalage mod and the other; not so much but a little which was all accomplished with the gluing of the CF arrow and not moving the HStab plastic saddle.

2" aluminium hub version has rare earth magnets on tail to adjust GC.

Varoius blue and white velcro strips on wing saddle and canopy are for 808 Key Cams and their external battery packs. The weight of the 800mah 1S external camera LiPo battery is also used to adjust CG by repositioning on the velcro.

3 images show an old Radian Pro servo bay and how I fixed the 2 Futaba antennas when I put the RX in the servo bay when the servos are both moved aft. For Spektrum users, the Futaba and Orange RX has 2 antennas on long pigtails and no satellite RX needed to get antenna diversity and the desired 90 degree offset.

At this time I have one mod on my todo list other than add some color. It has to do with the wing flex. I do not believe that the excess flex is due to the wing spar being too weak all though that can contribute some. I believe the compression of the foam surrounding the wing spar, particularly near the wing root and at the top of the spar, when experiencing high-G contributes move flex. I will try to solve this by gluing a tubular insert into each wing root for about the first 6" or so. The lighter, thinner walled wing spar that comes with the Radian ( as opposed to the heavier, thicker walled one that comes with the Radian Pro ) will allow me to insert a Caleba CF arrow into it. I have flown with the factory CF tube AND the CF arrow inserted and have found little difference. i.e. the foam can still compress above the spar near the root. So I will cut about 6" pieces of the Radian spar and glue them into the wing and then use the CF arrow as the spar. It will be somewhat loose on the outer wings as its OD is aproximately the same as the ID of the factory spar. BUT, the spar near the root will have to deal with both the compression on the upper surface and sheer on the lower. The flexing wing should encounter more resistance around the root with the glued-in insert rather than just having to compress the foam above the spar. Small movement near the root translate into big wing flex near the tips.

If it works... I'll report back. If it is NG I won't will admit it was a dumb idea and won't will report back


Thanks

This is a great post ..
Loads of info with photos..



Sean.


.
skyhawk newbie is offline Find More Posts by skyhawk newbie
Reply With Quote
Old May 08, 2012, 12:49 PM
ich bauen groß modell flugzeug
Keenan smith's Avatar
United Kingdom, London
Joined Dec 2010
6,830 Posts
Well im a Glider pilot in training and id say flying hands off and having the tailplane incedence set correctly can make a load of differance

Keenan
Keenan smith is offline Find More Posts by Keenan smith
Last edited by Keenan smith; May 08, 2012 at 10:15 PM.
Reply With Quote
Old May 08, 2012, 08:15 PM
Chess club geek with wings
blunight's Avatar
United States, FL, Cape Coral
Joined Aug 2008
1,054 Posts
I flew my Radian for the first time today after completing the mods Paul Naton recomended - I set my CG at 3.5" from the LE.

The wind was 7 mph with frequent gusts to 15.

After getting it trimmed it was a pleasure to fly. It flys much closer to stall speed and indicates lift much better now. Penetration into the wind seems better although I suspect it's more due to it's reluctance to porpoising as it did before the mod - it now just flys straight ahead.

Full power now requires a touch of up elevator - that's going to take some getting used to.

If I were buying a brand new Radian I'd perform these modifications before flying, they make that much of a difference.
Trent
blunight is offline Find More Posts by blunight
Reply With Quote
Old May 09, 2012, 07:51 AM
turn, turn, turn.
Athol, Massachusetts
Joined Oct 2005
10,262 Posts
Why don't you guys just dial in a bit of down elevator?
Kenny Sharp is online now Find More Posts by Kenny Sharp
Reply With Quote
Old May 09, 2012, 09:00 AM
Registered User
Joined Feb 2006
579 Posts
Quote:
Originally Posted by Kenny Sharp View Post
Why don't you guys just dial in a bit of down elevator?
Kenny asks the right question. The most important part of the recommended mods is the movement of the CG to the rear. The stabilizer decalage is much less important and may not give a significant difference in performance. There has been endless discussion on RC Groups about the stab decalage. Much of this discussion about achieving improved performance has become confused because the decalage was changed and the CG was moved at the same time.

See the writeup by MIT chaired Professor of Aeronautics and Astronautics Mark Drela.

http://www.polecataero.com/handlaunchu/cg-location
williamson is offline Find More Posts by williamson
Reply With Quote
Old May 09, 2012, 09:44 AM
Not a newbie anymore..
skyhawk newbie's Avatar
Ireland, Cork
Joined Oct 2010
2,027 Posts
Quote:
Originally Posted by williamson View Post
Kenny asks the right question. The most important part of the recommended mods is the movement of the CG to the rear. The stabilizer decalage is much less important and may not give a significant difference in performance. There has been endless discussion on RC Groups about the stab decalage. Much of this discussion about achieving improved performance has become confused because the decalage was changed and the CG was moved at the same time.

See the writeup by MIT chaired Professor of Aeronautics and Astronautics Mark Drela.

http://www.polecataero.com/handlaunchu/cg-location
I like this part the best in his write up...

Where you want the CG to be should depend on personal preference and flying style. Some people fly with the CG well forward. Others seem to fly with the CG as far back as is tolerable.

Each to there own....

.
skyhawk newbie is offline Find More Posts by skyhawk newbie
Reply With Quote
Old May 09, 2012, 09:49 AM
Not a newbie anymore..
skyhawk newbie's Avatar
Ireland, Cork
Joined Oct 2010
2,027 Posts
Does anyone fly a no decalage mod , but has there CG set aft ?

or it anyone flying Decalage with stock CG ?


.
skyhawk newbie is offline Find More Posts by skyhawk newbie
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question I Need Competition Mods for a Radian Pro Kenny Sharp Electric Sailplanes 4 May 02, 2012 07:08 AM
Help! Lost post on Radian Pro mods - just found it! JBGROS Sailplane Talk 1 Apr 02, 2012 07:27 PM