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Old Dec 11, 2008, 06:16 PM
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sylifis's Avatar
So. Calif.
Joined Nov 2008
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Quote:
Originally Posted by beginner4life
What do you guys think about a 1500 mah 3s?
I see a lot of different posts regarding the size of the battery...the trade off is how light do you want your sailplane to be, the CG doesn't seem to be an issue as it can be adjusted either by moving the battery forward or aft and if necessary a counter weight, like a penny taped in place. I really enjoy this Radian and I have been using a 2100 mah 3s Align battery from day one (never used the smaller one that it came with) that weighs 5 oz, and it lasts me most of the day, I usually tire out before the battery. Purists may say that it glides better with the less weight especially in a thermal. But, my experience is that it glides just fine with the 2100mah. In addition to the 2100mah I also have a flycamone2 about six inches out from the fuse and a magnet holding a small nut/bolt on the other wing to counter balance. The flycamone2 weighs in at 40 gm. the way I mounted it and the nut/bolt is exactly 40 gm. also. I find that the Radian handles better with a little extra weight, otherwise with any wind in excess of 8-10mph it tends to get blown around a lot.
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Old Dec 11, 2008, 06:48 PM
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eagleswings's Avatar
United States, CO
Joined Dec 2006
986 Posts
Quote:
Originally Posted by sylifis
I see a lot of different posts regarding the size of the battery...the trade off is how light do you want your sailplane to be, the CG doesn't seem to be an issue as it can be adjusted either by moving the battery forward or aft and if necessary a counter weight, like a penny taped in place. I really enjoy this Radian and I have been using a 2100 mah 3s Align battery from day one (never used the smaller one that it came with) that weighs 5 oz, and it lasts me most of the day, I usually tire out before the battery. Purists may say that it glides better with the less weight especially in a thermal. But, my experience is that it glides just find with the 2100mah. In addition to the 2100mah I also have a flycamone2 about six inches out from the fuse and a magnet holding a small nut/bolt on the other wing to counter balance. The flycamone2 weighs in at 40 oz. the way I mounted it and the nut/bolt is exactly 40 oz. also. I find that the Radian handles better with a little extra weight, otherwise with any wind in excess of 8-10mph it tends to get blown around a lot.
Thanks S!

VERY good news for me. I standardize my entire fleet on 1800 lipos and really don't want to buy any more batteries. That's good to hear your great report!

Thanks again,
Mike
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Old Dec 11, 2008, 07:03 PM
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Fairfield, CA
Joined Apr 2002
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sylifis: Yep, there is no doubt that the plane will fly well with a 5oz battery. Actually, thats pretty light for a 2100. The 3S-1300s range in weight from 3.4 to 4.4 (typically, including deans connectors.).

Opps...I guess I forgot to mention, I converted the plane to runs on the Deans connector.

Anything larger than 3S-1300 just extends the flight time, and adds weight to the plane. But even if sylifis adds 5 oz battery instead of 4 oz, that still a pretty light plane.

- Richard
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Old Dec 11, 2008, 07:06 PM
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United States, CO
Joined Dec 2006
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It looks like my 1800's weigh in at slightly over 5 ounces...so I still should be okay!

Take care,
Mike
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Old Dec 11, 2008, 07:24 PM
It works, don't touch it.
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Joined Dec 2007
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My parkzone 1800 weighs 4.8 ounces or at least that is what my scale says and i am going to get a 2200 soon which supposedly weighs 6 ounces.
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Old Dec 11, 2008, 08:54 PM
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Fairfield, CA
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Yah Guy....I wouldn't sweat it. You will have to carve out a bit of foam to fit a bigger battery. No biggie. Go have fun!!! - Richard
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Old Dec 11, 2008, 11:22 PM
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C Carlton,

1) I don't know if you realize it, but those are excellent RC plane photos. Maybe the best I've seen. Especially the ones looking down on the plane, as, its looks like the photos are taken from a second plane above.

2) You should inform your son, how lucky he is to have a dad, who has made available a nice new plane, that, he can borrow, walk up a hill, and fly. Certainly, worth a sincere hand shake, a smile, and a "Thanks Dad".

3) When you took your photos, any special tricks/suggestions to get such a clear focus and centered photo of a moving rc plane with a digital camera? Did you use a zoom feature?

4) If a battery weighs a little more or less than the Radian oem, is there enough room in the cockpit, to move it forward or back, to keep the CG exactly the same as from the factory, or as calculated by the NASA CG calculator? ... Or, was that what you meant, when you said something about carving out the foam? (and after carving, and maybe laying in some velcro (?) then the optimum cg would be able to be maintained with different battery wts/sizes in the Radian?)

5) Does the prop seem sturdy enough to take hard nose landings on unplanned occasions? Did it come with a spare prop? If not, would it be wise, to order a second prop for backup with the initial plane order?

6) What's that nice looking twin engine plane in the last photo? Foam, or ? Wingspan? Motor/battery type size? Price? Experience level required?

7) Just a thought, ... how about bright yellow stripes on the bottom of the main wing, that match the size and placement of the red stripes on top, maybe with a thin black line (permanent felt tip marker) on the edge of the yellow on the sides where it meets the white?


8) Any tips, on how to fly a 3 ch dihedral wing glider successfully, upside down? I tried once on my 55" 3 ch. dihedral wing Wild Hawk, without success (broke wing in half, broke fuselage half in half, quickly, long story). Another more experienced person tried it with my plane a while ago, and I think he was able to do it, but, as I recall, it didn't seem fly very long upside down.

---

Look forward to your comments, in a 10 mph or so wind test flight. It may blow it around a bit. ... But that's not bad, that's just what happens with a lighter plane, light on its feet/wings so to speak, to allow it to hang lighter, longer, in the air.

My 3 ch. $65 RTF 55" Wild Hawk (about 22 oz. or so, with the 7 cell ni-mh oem battery) is like that, in winds. Its flyable in faster winds, but requires faster reactions, and is tossed around a bit, & harder to land. ... If its windy, it depends on my mood, if I fly or not, ... i.e., if I'm so desperate to fly, because I have not flown for a while, I'll fly it anyway, even though I know I'm going to have a challenging risky flight, and be tossed around. Using a heaver battery on windy days, seems to stabilize it a little. But, even with the heavier battery, it's still a more attention demanding in higher winds, as would be expected. In a way, the faster winds are good flight training, as long as one uses extra care, and can get lucky enough to fly and land without damage.

I re-checked my cg with the online NASA CG calculator, and it seemed a little off with my rough battery placement. After making the right battery shift adjustment, it did indeed fly better.

CG is so important. It may be the most important single factor, on a plane. Being new rc flying, I have learned its wise, to re-check it from time to time, to make sure, the cg mark I make under the wing is right, and its flying (any plane) with its optimum cg. And to watch the planes' flight, and attempt to tweak the cg, to each planes ultimate optimum for best possible flight.
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Old Dec 11, 2008, 11:34 PM
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Joined Dec 2008
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Radian Sale

FYI I just bought the Radian PNP at Ultimate Hobbies in Orange California for $124.99. It is on sale but I don't know for how long.
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Old Dec 12, 2008, 12:23 AM
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Fairfield, CA
Joined Apr 2002
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1) I don't know if you realize it, but those are excellent RC plane photos. Maybe the best I've seen. Especially the ones looking down on the plane, as, its looks like the photos are taken from a second plane above.

Slope Soaring Field. We were at the top with the Camera.

3) When you took your photos, any special tricks/suggestions to get such a clear focus and centered photo of a moving rc plane with a digital camera? Did you use a zoom feature?

The camera is a Nikon D80, with a variable zoom lense with built in image stabilization. We shoot the camera is "Sports Mode" for faster shutter speeds. .


4) If a battery weighs a little more or less than the Radian oem, is there enough room in the cockpit, to move it forward or back, to keep the CG exactly the same as from the factory, or as calculated by the NASA CG calculator? ... Or, was that what you meant, when you said something about carving out the foam? (and after carving, and maybe laying in some velcro (?) then the optimum cg would be able to be maintained with different battery wts/sizes in the Radian?)

The spot where the battery is placed is designed for a 3S-1300. If you stuff a bigger battery in it, then the battery CG is moved forward, moving the whole aircraft CG forward. Alternatively, you can cut the rear of the battery compartment to make room for a larger pack.


5) Does the prop seem sturdy enough to take hard nose landings on unplanned occasions? Did it come with a spare prop? If not, would it be wise, to order a second prop for backup with the initial plane order?

The plane lands so slow, that I don't think there is going to be a problem with the prop getting broken. That being said, a good pilot should try to cycle the prop so it is sideways before landing.


6) What's that nice looking twin engine plane in the last photo? Foam, or ? Wingspan? Motor/battery type size? Price? Experience level required?

That Photo is a Grumman S-2 with the aforementioned CDF paint Job. 43 foot wing span, Aluminum and steel construction, the plane are FREE to CDF, except they contract Dyncorp to retrofit turbine engines, radios, tank, etc. So they are a minimum of 3 million each (probably a lot more). CDF requires applicants to have a multi-engine commercial rating and atleast 2500 hour of flight time.


8) Any tips, on how to fly a 3 ch dihedral wing glider successfully, upside down? I tried once on my 55" 3 ch. dihedral wing Wild Hawk, without success (broke wing in half, broke fuselage half in half, quickly, long story). Another more experienced person tried it with my plane a while ago, and I think he was able to do it, but, as I recall, it didn't seem fly very long upside down.

Flying the Radian right side up... is very easy...pretty much hands off. Flying it upside down takes constant corrections, and I find it more difficult than flying a helicopter. It wasn't design for that. The plane constantly wants to "roll out" and correct itself to upright level flight.
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Old Dec 12, 2008, 12:35 AM
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Fairfield, CA
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CG is so important. It may be the most important single factor, on a plane. Being new rc flying, I have learned its wise, to re-check it from time to time, to make sure, the cg mark I make under the wing is right, and its flying (any plane) with its optimum cg. And to watch the planes' flight, and attempt to tweak the cg, to each planes ultimate optimum for best possible flight.

Mr Cash,

Your a bit obsessed with the CG. 32.5% is NOT the correct center of gravity for every wing, on every plane. The CG depends on the design of the wing, and is a conversation for another thread elsewhere. For RC pilots, we start with the manufacturer recommend CG, and then adjust that CD to change the performance of the aircraft to fit out flying style. Consider this...most of the IMAC Aerobatic pilots, burn gas, or nitro, and as the fuel burns off...the CG on their planes can change. They try to minimize this, but it happens. But they still win championships, etc.

The CG can move on your plane, and you won't be struck dead.


So Back on to the Radian, the manufacturer CG is right on he money. :-)
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Old Dec 12, 2008, 01:27 AM
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Adelaide Plains Australia
Joined Dec 2007
3,434 Posts
hi guys, after a little help please

I'm looking for batteries for this glider, i found a few different ones available but wondered about a couple of things i can't find the info for. Can someone please tell me the dimensions of the stock S-1300

the batts I'm looking at are: 1500mah 11.1v 25c Size : 67mm 34.5mm 22.5mm and weigh 110g

also does it matter what C rating you use, the ones i am looking at are 25C but i did notice some S-1300 batts were as low as 10C do you need a certain C rating for this glider? would 15C be enough?

thanks for any help you can offer

cheers chuck

PS. Captain Carlton great report and photos
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Old Dec 12, 2008, 02:35 AM
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Captain Carlton's Avatar
Fairfield, CA
Joined Apr 2002
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Hey Chuck,

The "C" rating does matter. So you looking for a battery like this...

http://www.hobbycity.com/hobbycity/s...C_Lipoly_Pack_

or this

http://www.hobbycity.com/hobbycity/s...idProduct=6308

The dimensions are right on this pack, and 20C would be good. 15C is boarderline.

Remember this plane sucks up 18 Amps, given the opportunity. I cannot vouch for Hobby City Batteries. Sometimes they are fine, sometimes they stink. I fly NEU Energy Batteries or Thunderpower. But its hard to go wrong for $13.00

If money is no object, look at these...specifically the TP1320-3SPL, which is third down on the right list.

http://www.thunderpowerrc.com/html/prolites.html

- Richard
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Old Dec 12, 2008, 04:50 AM
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Adelaide Plains Australia
Joined Dec 2007
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Thanks for that CC

just might treat myself to this glider for Christmas i have an AR6100 and just needed a battery so i can buy the pnp version

again thanks for the help

cheers chuck
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Old Dec 12, 2008, 08:33 AM
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United States, TX, Highland Village
Joined Jan 2003
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Quote:
Originally Posted by Captain Carlton
CG is so important. It may be the most important single factor, on a plane. Being new rc flying, I have learned its wise, to re-check it from time to time, to make sure, the cg mark I make under the wing is right, and its flying (any plane) with its optimum cg. And to watch the planes' flight, and attempt to tweak the cg, to each planes ultimate optimum for best possible flight.

Mr Cash,

Your a bit obsessed with the CG. 32.5% is NOT the correct center of gravity for every wing, on every plane. The CG depends on the design of the wing, and is a conversation for another thread elsewhere. For RC pilots, we start with the manufacturer recommend CG, and then adjust that CD to change the performance of the aircraft to fit out flying style. Consider this...most of the IMAC Aerobatic pilots, burn gas, or nitro, and as the fuel burns off...the CG on their planes can change. They try to minimize this, but it happens. But they still win championships, etc.

The CG can move on your plane, and you won't be struck dead.


So Back on to the Radian, the manufacturer CG is right on he money. :-)
Particularly for sailplanes CG is subjective. I prefer an aft CG as the airplane will indicate lift better, but it is harder to fly. Of the guys I fly with, we all have a different, very subtle preference. Some will change based on conditions, I do not.

In general, manufactures suggest a more conservative CG. I flew my old spirt for years this way, plowing around the sky, never finding lift, until I found the interent and read a bit!

So experiment with it, move it back as far as you can stand it, then nudge it forward, all based on test flights.

Word among guys who I condider world class sailplane pilots is that the Radion flys real nice with a quater taped to the tail ...... we'll see, give me a week or so with mine.
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Old Dec 12, 2008, 09:28 AM
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So. Calif.
Joined Nov 2008
464 Posts
For purposes of comparison, here is a website that shows the battery I am using, the Align20C (I originally used this on my Trex 450) and they show the wt. to be 140gm which is 4.93oz without Deans, I added Deans connectors and get an even 5oz. on my scale.

http://www.completeheli.com/index.ph...fec7c3732b630d

I added a small piece of foam about 1/2 inch thick to the bottom recess of the cockpit to push the battery forward and marked that spot with red ink. I added an additional velcro horizontally anchored to a post that is crazy glued, this runs across the top of the battery; so I have velcro length and width. It is very secure as I like to do a few loops and upside down flying once in a while. I might mention that any upside down flying should be done at a sufficient height to allow recovery as the Radian definitely tends to roll off and drop quite a bit. My only crash so far has been not following my own advice and being too low. It is a sailplane first and foremost, but the rolls and upside down flying is just a way of increasing my handling responses. The metal clevis's give me greater security and seem to be more responsive, I also used one size larger piano wire which fit into the existing pushrod tubes, it seems to help hold the elevator and rudder positions without impinging on the servo movements. I might also mention that, although the flycamone2 and the counterweight are removable, I purchased a second set of wings from Horizon so that I have a clean wing surface depending on wind conditions on flyday.

Here are a few pics.

#1 Align 2100mah 5oz. 20C battery
#2 metal clevis used on both elevator and rudder soldered in place.
#3 rare earth magnets super glued in each wing to hold wings together (previously wings slipped out too easy)
#4 flycamone 2 (40gm) mounted (the blue tape is my 2.5inch measured CG)
#5 counterweight (same distance out) on opposite wing (nut/bolt) 40gm held by two super magnets embedded and super glued into the wing.
#6 the two magnets embedded in wing to hold counter wt.
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