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Aug 31, 2011, 09:09 AM
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fly2bob's Avatar
Sorry guys I've been ignoring this thread I started. Ok, so I ended up buying a used regular old Radian for my girlfriend to learn on, stock prop is on it I believe. We are going to use a HK turigy (something like that) 3s 2200 lipo on it. I took it and her to Blossom Valley here in San Diego to test it out and see if I could get here some stick time in. BV is a 1000' inland slope w/ great thermals. It was too crowded for her liking to feel comfortable flying since there were diapers in the air too, but I test flew it just as a sloper and got it trimmed out. Flies great, just like that sort of glider should. It reminds me of back in the days when I started out learning to fly on a Wanderer. I'm gonna do the horizontal removable stab modification on it for her so it will all break down back into the box for her. We'll probably go electric fly it this weekend. I also do have a Easy Star that I am modifying to a brushless system, but that is for my nephew. His will use a 3s 2500 pk. I was gonna use the new 2200 packs I bought for that one, but weighed them both, and they weigh the same. The 2500 are old, so he gets those. I was even concerned about the EZ * using the 2200 pks until I read the article on the conversion and the author used a 3s 1600 pk and had to add some nose weight to balance it. Also I saw everyone else was using 2200 pks. That is probably why....you can either use a 1600-1800 pk and add nose weight to balance it, or just use a 2200 pk and not have to add nose weight.

Cheers,

Bob
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Aug 31, 2011, 01:56 PM
Registered User
By the way, you guys are comparing a model from 10 years ago, to now.. Just saying..

Oh and They are both great, but I like working with elapor and it's repairs are easy. Radian you get locked down to epoxy (heavy).

But overall the radian is better to start with, it has.. well everything :-)
Aug 31, 2011, 09:31 PM
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alibongo's Avatar
Quote:
Originally Posted by fly2bob
Well I think the original Radian will be a good first glider for my girlfriend. It'll straighten itself from a banked turn more so than a Radian Pro. That could be her second glider.

Bob
I bought a Radian Pro, couldn't work out how to program my radio (I'm new to them, working on it), so bought a pair of Radian wings.Bit of work with a knife and a hot screwdriver blade, and they plug in nicely.I put a bit of masking tape on each side where wings join fus, but doubt if I really need it.Reckon I have the best of both worlds.
Aug 31, 2011, 11:24 PM
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fly2bob's Avatar
Quote:
Originally Posted by ZSimon
By the way, you guys are comparing a model from 10 years ago, to now.. Just saying..

Oh and They are both great, but I like working with elapor and it's repairs are easy. Radian you get locked down to epoxy (heavy).

But overall the radian is better to start with, it has.. well everything :-)
actually i think you can use ca
Sep 01, 2011, 12:10 PM
Foam flogger
3s 2200 will make the Radian nose heavy. Probably ok for a beginner or sloping, but it won't float as nice as if you were running a 1300 and might porpoise a bit.
Sep 01, 2011, 01:18 PM
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fly2bob's Avatar
Quote:
Originally Posted by Belem
3s 2200 will make the Radian nose heavy. Probably ok for a beginner or sloping, but it won't float as nice as if you were running a 1300 and might porpoise a bit.
With a little bit of foam removed from the rear (in front of the servos) it balances out ok. This will be my girlfriends first attempts at flying, so a little nose heavy will be good. People use 2200 pks in their Easy star, because if they don't, they have to add some lead to the nose to balance it out. It flies fine like that and it has a much shorter wingspan. And my 4m Alpina weighs 12lbs and it thermals great, so I'm sure it'll be fine. Later on when she gets better we can try using a 1300 pk more forward towards the nose when she gets the desire to try thermaling. I understand w/ a lighter weight it will fly slower which is good for a beginner, but also w/ a higher capacity battery she'll get more climbs in each flight. Like I said, I'm sure it'll be fine.

I am going to trade out those nasty servos for better ones though and make the horizontal stab removeable w/ magnets. Do you guys just use the stock prop blades, or do most upgrade to a larger or higher pitch prop?

thanks,

Bob
Sep 01, 2011, 04:12 PM
Registered User
Quote:
Originally Posted by fly2bob
People use 2200 pks in their Easy star, because if they don't, they have to add some lead to the nose to balance it out.
thanks,

Bob
Huh?? I use 1500 25C lipo in my EZ and have never had to add ballast... There's so much room I can move it forward or backward to get the 78mm CG based on which camera I have mounted
Sep 01, 2011, 05:27 PM
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fly2bob's Avatar
Quote:
Originally Posted by rtbates
Huh?? I use 1500 25C lipo in my EZ and have never had to add ballast... There's so much room I can move it forward or backward to get the 78mm CG based on which camera I have mounted
Well if you have a camera mounted on it, maybe that's why the 1500 is a large enough battery to balance it.
Sep 01, 2011, 07:34 PM
Drone offender FA377YHFNC
Quote:
Originally Posted by fly2bob
I am going to trade out those nasty servos for better ones though and make the horizontal stab removeable w/ magnets. Do you guys just use the stock prop blades, or do most upgrade to a larger or higher pitch prop?

thanks,

Bob
Bob, I'd nix the magnets. One thing you don't want to do with a Radian is add weight to the tail. I'd stick with Scotch tape to hold the stab in place. It weighs nothing, is plenty strong (use four strips, top and bottom) and easily removable.

Once she gets experienced with the plane, I found that the sweet spot for the CG is 70mm aft of the leading edge of the wing. Seemed like my sink rate was cut in half, while the plane remained quite controllable. I had trouble flying the thing at 72mm because it really stopped caring whether it flew straight or sideways. It demanded much more active flying then and wasn't comfortable in a turn at all. With more experience on my part, 72mm might be fine. But 70mm was quite stable and what it did to the sink rate was magic.

I agree with you on the servos. A pair of HK15178s would be a great tradeout and $1.69 per servo is pure joy.
Sep 01, 2011, 09:21 PM
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fly2bob's Avatar
Quote:
Originally Posted by Rockin Robbins
Bob, I'd nix the magnets. One thing you don't want to do with a Radian is add weight to the tail. I'd stick with Scotch tape to hold the stab in place. It weighs nothing, is plenty strong (use four strips, top and bottom) and easily removable.

Once she gets experienced with the plane, I found that the sweet spot for the CG is 70mm aft of the leading edge of the wing. Seemed like my sink rate was cut in half, while the plane remained quite controllable. I had trouble flying the thing at 72mm because it really stopped caring whether it flew straight or sideways. It demanded much more active flying then and wasn't comfortable in a turn at all. With more experience on my part, 72mm might be fine. But 70mm was quite stable and what it did to the sink rate was magic.

I agree with you on the servos. A pair of HK15178s would be a great tradeout and $1.69 per servo is pure joy.
They are two tiny rare earth magnets, quite light. Not worried about it. I can always have the battery not as far back. I'll have to check where I have the CG right now, and I'll report back. And I'll keep your sweet spot suggestion in mind for later. Thanks, Bob
Sep 02, 2011, 10:31 AM
Drone offender FA377YHFNC
Quote:
Originally Posted by fly2bob
They are two tiny rare earth magnets, quite light. Not worried about it. I can always have the battery not as far back. I'll have to check where I have the CG right now, and I'll report back. And I'll keep your sweet spot suggestion in mind for later. Thanks, Bob
I did the rare earth magnet bit. Even though they were only quarter inch diameter, you'll need to use at least four of them to do the job, two in the stab, two on the stab mount plastic. Even then you'll have more movement than you had with scotch tape. It really isn't satisfactorily stationary unless you've used a total of 8 magnets, two on each side of the vertical stab for each horizontal stab and plastic stab mount.

Okay, my magnets are .25" diameter and .125" thick for a total of 11 grams apiece. Eight of them was a ridiculous 88 grams on the exact wrong part of the plane! The Radian has a pretty long tail moment, so that was truly unacceptable. I ended up removing all tail weight from my plane and using four magnets, still weighing 44 grams, still weighing more than an ounce and a half. Then I was no longer happy with the rigidity of the assembly.

Finally I concluded that aeajr was right. Tape weighs nothing. It is many times more rigid than the magnets. It's no big deal to carry a roll in the flight box. I just don't see any justifiable reason to use the rare earth magnets unless it's just for the cool factor "look! I used magnets!" Since the magnetic flux density is directly related to the weight of the magnets, using smaller ones would only make the airframe less rigid than I had when I didn't think it was rigid enough. If you put a flight load on the elevator, the stab could move (usually twisting), changing the elevator position. That's called loss of control and a possible situation where in a fast dive you could lose any elevator authority.

Keep it simple! Tape rules over all! My magnets are in a box on my bookshelf. They work very well there.
Sep 02, 2011, 02:10 PM
Volts>amps
stgdz's Avatar
Sonny over in the radian pro thread put a graupner 11x7 prop and al spinner on it.

He posted a video on it. It was a dot in the sky from launch after about 45 seconds.
Sep 02, 2011, 05:21 PM
Registered User
fly2bob's Avatar
Quote:
Originally Posted by Rockin Robbins
I did the rare earth magnet bit. Even though they were only quarter inch diameter, you'll need to use at least four of them to do the job, two in the stab, two on the stab mount plastic. Even then you'll have more movement than you had with scotch tape. It really isn't satisfactorily stationary unless you've used a total of 8 magnets, two on each side of the vertical stab for each horizontal stab and plastic stab mount.

Okay, my magnets are .25" diameter and .125" thick for a total of 11 grams apiece. Eight of them was a ridiculous 88 grams on the exact wrong part of the plane! The Radian has a pretty long tail moment, so that was truly unacceptable. I ended up removing all tail weight from my plane and using four magnets, still weighing 44 grams, still weighing more than an ounce and a half. Then I was no longer happy with the rigidity of the assembly.

Finally I concluded that aeajr was right. Tape weighs nothing. It is many times more rigid than the magnets. It's no big deal to carry a roll in the flight box. I just don't see any justifiable reason to use the rare earth magnets unless it's just for the cool factor "look! I used magnets!" Since the magnetic flux density is directly related to the weight of the magnets, using smaller ones would only make the airframe less rigid than I had when I didn't think it was rigid enough. If you put a flight load on the elevator, the stab could move (usually twisting), changing the elevator position. That's called loss of control and a possible situation where in a fast dive you could lose any elevator authority.

Keep it simple! Tape rules over all! My magnets are in a box on my bookshelf. They work very well there.
Ok, ok, I think you've convienced me. I'll have to rethink it. I'd just like it to break down some. Maybe I'll go w/ a removeable fin. I'll see, thanks.
Sep 02, 2011, 06:06 PM
Drone offender FA377YHFNC
Quote:
Originally Posted by fly2bob
Ok, ok, I think you've convienced me. I'll have to rethink it. I'd just like it to break down some. Maybe I'll go w/ a removeable fin. I'll see, thanks.
Hmmm. .. Seems to me that a removable fin a shoulder mounted horizontal stab might be problematic. It would have to be mighty stiff. Just a suggestion, but if I were going to add weight to the thing it would be to make the fuselage stiffer from the wing back. After all, if you keep the stab removable you can use the box for storage and with a little reinforcement of the box it will do for a very long time.

Somewhere around here I have a You Tube video on reinforcing the fuselage using carbon tow and epoxy resin. When I find it I'll post it here.
Sep 02, 2011, 08:40 PM
Registered User
fly2bob's Avatar
Quote:
Originally Posted by Rockin Robbins
Hmmm. .. Seems to me that a removable fin a shoulder mounted horizontal stab might be problematic. It would have to be mighty stiff. Just a suggestion, but if I were going to add weight to the thing it would be to make the fuselage stiffer from the wing back. After all, if you keep the stab removable you can use the box for storage and with a little reinforcement of the box it will do for a very long time.

Somewhere around here I have a You Tube video on reinforcing the fuselage using carbon tow and epoxy resin. When I find it I'll post it here.
You tube is where I saw the video on the removeable stab. Seemed like a good idea to me to be able to use the box for storage and transportation.

Bob


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