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Old Mar 19, 2012, 12:38 AM
Less Work More Play
LWMP's Avatar
Australia, VIC, Ferntree Gully
Joined Jan 2012
88 Posts
Thanks, I will try removing some of that foam first,
I am pretty comfortable at 70mm so I stick with that for now.
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Last edited by LWMP; Mar 19, 2012 at 04:58 PM.
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Old Mar 19, 2012, 01:14 AM
Kool Kats Fly RC!! AMA 30462
sonny1's Avatar
United States, CA, Baywood-Los Osos
Joined Feb 2009
2,669 Posts
Quote:
Originally Posted by LWMP View Post
I have a question regarding larger batteries.

If I try to put my 1600mah 3s in the RP the COG shifts way forward (to about 60mm). I notice that many people are running 2200mah packs in theirs which would make them very nose heavy indeed. Are people digging out foam to get the CoG back or are they adding ballast to the tail? With my 1300mah Zippy pack it is smack on 70mm which from what I read in the previous posts is too far forward for many.
I use Enerland 2200mah packs, which are less narrow than typical 2200's so they fit into the RP, (barely, but they fit). My rx is a Hitec Minima, so it doesn't take up much room and there is nothing obstructing the battery tray. I use that size lipo only in windy conditions, precisely because it makes the plane nose-heavy so it will penetrate into a stiff wind, (I wanted to say "upwind", but I know I better not). Mind you, I almost never run the motor for longer than the initial 30 second climb-out and try to get back without powering up again, (if possible; in an ALES contest an "emergency" motor start after the initial climb of 30 seconds is a zero-round, so I practice using one climb-out per flight), so to get back home in windy conditions it's easier when it's a bit nose heavy. I normally use a 1300mah pack in average flight situations, but in addition to the 2200 I have also used 1600 & 1800mah packs and just trim as needed for the conditions. I suspect others who are using 2200 packs are doing so for the same reasons as I am.

Sonny
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Old Mar 19, 2012, 01:35 AM
Kool Kats Fly RC!! AMA 30462
sonny1's Avatar
United States, CA, Baywood-Los Osos
Joined Feb 2009
2,669 Posts
Hmmm, though I should mention that the ideal situation would be to add ballast to any sailplane at the COG to improve performance in windy conditions, but since that isn't so easy to do in the Radian Pro I simply use a larger lipo and fly the plane slightly nose-heavy. A few posters have mentioned using an iron rod in place of the carbon wing tube as a means of adding ballast, but barring that it would be difficult to add ballast at the COG on the RP without carving space in the foam for it.

Just a heads up...Value Hobby now stocks 50mm aluminum spinners, (the correct replacement size for the RP): http://www.valuehobby.com/accessorie...ding-prop.html, though for some reason it seems to only come with a 5mm shaft adapter. At least it's another possible source of the sometimes hard to find 50mm aluminum spinners, (though the adapter size issue would need to be addressed if using the stock motor).

Sonny
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Old Mar 19, 2012, 05:57 AM
Night flier
United Kingdom, England, Bromyard
Joined Mar 2008
824 Posts
Hi looking at buying this model for FPV. Wont buy the BNF version as i only use Futaba 10C tranny. But im wondering wot size battery will fit and wot flight time people are getting. Looks a nice model and from watching the videos at the start of this thread it looks like it could be a great model for FPV. Any info would be good. Thanks austin.
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Old Mar 19, 2012, 07:31 AM
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Joined Jan 2010
3,091 Posts
I will start by saying that I do not do FPV. but have done AP and know the requirements.

IMO the RP is far from the ideal FPV platform, mainly because there is not enough room for the necessary navigation and downlink equipment. As you can derive from the preceding posts it is possible to fit a 2200 mah battery but that will not leave room for anything else. If for some reason the idea of a sail plane is still appealing the standard Radian would probably be a better choice. You don't need full house controls for FPV, and the standard version is a more stable ship.
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Last edited by kaptondave; Mar 19, 2012 at 07:38 AM.
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Old Mar 19, 2012, 07:44 AM
Night flier
United Kingdom, England, Bromyard
Joined Mar 2008
824 Posts
Quote:
Originally Posted by kaptondave View Post
I will start by saying that I do not do FPV. but have done AP and know the requirements.

IMO the RP is far from the ideal FPV platform, mainly because there is not enough room for the necessary navigation and downlink equipment. As you can derive from the preceding posts it is possible to fit a 2200 mah battery but that will not leave room for anything else. If for some reason the idea of a sail plane is still appealing the standard Radian would probably be a better choice. You don't need full house controls for FPV, and the standard version is a more stable ship.
Thanks good point too. i like the look of the radian pro but i will check out the radian. thanks austin.
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Old Mar 19, 2012, 12:18 PM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,284 Posts
Quote:
Originally Posted by LWMP View Post
I have a question regarding larger batteries.

If I try to put my 1600mah 3s in the RP the COG shifts way forward (to about 60mm). I notice that many people are running 2200mah packs in theirs which would make them very nose heavy indeed. Are people digging out foam to get the CoG back or are they adding ballast to the tail? With my 1300mah Zippy pack it is smack on 70mm which from what I read in the previous posts is too far forward for many.
I wouldn't remove foam from the fuselage. The structure is weak enough as it is. I would add ballast to the tail, or just trim it when using a heavier battery.
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Old Mar 19, 2012, 01:15 PM
Somewhere lost in Texas
United States, TX, Flower Mound
Joined Jan 2011
276 Posts
Quote:
Are people digging out foam to get the CoG back or are they adding ballast to the tail?
I dug a bunch of foam out in order to get the larger battery to fit/work for those windy conditions which we tend to have here from about March to mid-May. I also CA'd in some 1/2mm carbon rods into the foam from the cowling to the back of the wing for added strength in the fuz.. Also for added ballast when needed, I substitute the CF spar with a 3/8 steel rod.. Works great..
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Old Mar 19, 2012, 02:01 PM
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Joined Jan 2010
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Quote:
Originally Posted by JumpySticks View Post
I wouldn't remove foam from the fuselage. The structure is weak enough as it is. I would add ballast to the tail, or just trim it when using a heavier battery.
I respect your opinion but I have removed quite a lot of foam between the battery and servo compartments and have seen no problem.
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Old Mar 19, 2012, 02:07 PM
I Fly!
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United States, AL, Huntsville
Joined Jan 2011
1,053 Posts
My Tenergy 11.1V 2100mAh 35C seems to fit in the spot fine and slides back far enough to allow almost the same CG as the stock 1300 packs. It is a bit nose heavy, but then again with this larger battery the plane is heavier and I can tell the difference now.

My weekend flights were timed perfect to my battery use, the last flight up the wind picked up a bunch and the RP was perfect with the added weight for the wind conditions. I flew the first 2 flights with stock 1300 and had great flight times and fun with the lite wind conditions.
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Old Mar 19, 2012, 05:00 PM
SSP ASP#88
labrown's Avatar
United States, NC, Durham
Joined Apr 2009
86 Posts
Oleg Golovidov won the first annual East Coast ALES contest this weekend flying a slightly modified Radian Pro!
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Old Mar 19, 2012, 07:35 PM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,284 Posts
Quote:
Originally Posted by labrown View Post
Oleg Golovidov won the first annual East Coast ALES contest this weekend flying a slightly modified Radian Pro!
Very cool. Everyone gonna have to make winglets now!

Congratulations Oleg!
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Old Mar 19, 2012, 10:45 PM
Seeker of Thermals
botulism's Avatar
United States, MT, Kalispell
Joined Aug 2004
581 Posts
Quote:
Originally Posted by JumpySticks View Post
I wouldn't remove foam from the fuselage. The structure is weak enough as it is. I would add ballast to the tail, or just trim it when using a heavier battery.
I've removed foam from the inside of the fuse in order to use 2200 maH packs. If I want to use 1300 or 1600 packs, I have to add little hunks of foam to keep it from sliding around. I don't think removing a few thin slices of foam from that area inside the fuse compromises the integrity of the fuse, as long as you don't overdo it. My 2200 packs fit rather snugly, so I've removed the least amount of foam I could. I'm totally against adding weight to the tail for cog balance unless absolutely necessary. Sometimes it's unavoidable though.

--
Greg
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Old Mar 20, 2012, 05:28 AM
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Norway, Akershus, Frogner
Joined Jun 2010
920 Posts
I just add a bit more trim. Works just fine for the plane
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Old Mar 20, 2012, 10:58 AM
Zor
Suspended Account
Ontario,Canada
Joined Feb 2007
9,742 Posts
Quote:
Originally Posted by botulism View Post
I've removed foam from the inside of the fuse in order to use 2200 maH packs. If I want to use 1300 or 1600 packs, I have to add little hunks of foam to keep it from sliding around. I don't think removing a few thin slices of foam from that area inside the fuse compromises the integrity of the fuse, as long as you don't overdo it. My 2200 packs fit rather snugly, so I've removed the least amount of foam I could. I'm totally against adding weight to the tail for cog balance unless absolutely necessary. Sometimes it's unavoidable though.

--
Greg
Hi Greg,

It is difficult for me to understand your reluctance to add a bit of weight to the tail for C og G balance when you are already adding lots of weight with a larger battery pack.

Zor
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