pzar

I have a GP Spirit Elite ARF. Used a micro radio and 1/2 size battery for weight. Looks great except for balancing it to meet the CG of 3.5". The nose is way light...I installed a fullsize battery 4 AA nicad and a 1 inch stack of washer and it is still tail heavy. This is supposed to be a glider ? To get this thing to balance it weighs a ton ? Any thoughts ?

Tall Paul

That's the way those things are coming out..
I was appalled to see the Elite ARF glider weighs more than my kit-built Elite, which has an electric motor AND battery for the motor!

BarracudaHockey

My Feedback: (11)

I replaced the metal push rods with carbon rods and put a 600Mah battery as far forward as I could get it. It still needed just a bit of lead in the nose but not much. I'm also looking for a carbon rod to replace the wing rod. I use piggy back launch and not winch so that shouldn't be a big deal. Check out rcgroups.com There's an EZine article on lightening that glider up.

Mine is still a bit heavier than I like, but it flys really well.

rscarawa

There is a doc on fixing that. let me find it. I one of the fixes was doing the carbon push rods for the elevator and another was pull-pull strings for the rudder (no clevises.).

BarracudaHockey

My Feedback: (11)

I did 2 push rods, although the pull pull probably would have been even lighter I didn't bother with it. Here's the article.

http://www.rcgroups.com/links/index.php?id=4102

rscarawa

http://www.rcgroups.com/links/index....at=251&id=4102

this may be the same article.

My only concern is that when he sets up the pull-pull, he does not offset the horn holes behind the rudder hinge line. This is a good practice since it will allow a small amount of slack to develop as the rudder is deflected. If you try to get it with 0 offset, you risk the possibility of having the holes offset infront of the hinge line. The consequence of this is that the strings become tighter and bind the servo as you defelct the rudder. You do not need much offset behind the rudder line, just a little to make sure you will develope some slack.

aeajr

My Feedback: (2)

Can you photo your internal set-up? maybe there is something that can be done by moving things around.

Done stock, my GP spirit 2MRES needed 4.5 oz to balance. after I moved some stuff around I got it down to 1.1 ounces.

danoman

In my personal opinion, you NEED a glider to have a little weight behind it... There have been many, many times that I've needed the extra weight behind a heavier glider model, when thermaling, the weight will help you "punch" through (especially punching OUT of) some of thoses stronger thermals. Here where I live (mid-Maine, USA) when you start getting season changes, the winds can be pretty strong and unpredictable.

If your concerned about having the ability to thermal because of the weight of the plane, (so long as it's not a 2M-10lb model... hehehe) Don't worry a bit... good thermaling ability is acquired when you get really used to your particular sailplane, and have the trim settings adjusted into the model. That's the key to thermaling... you want the model to fly absolutely straight without any input from the transmitter to keep it flying at level "predictable" slope.

Now that it's flying exacially where you have put it, and are used to your sailplane, move the CG back just a tad... you know you'll have it right when you can see the wingtips "lightly" lifting higher on one side or the other, or rocking a little on absolute level flight. Usually you can "see" the thermal by the wingtips... it will push the plane away from the thermal that you just saw the wingtip lift from... just try to turn the sailplane as flat as you can back into where you saw the wingtip lift... with a little practice, you'll be able to fly several hours from one toss or high start. (that is if you have some thermaling where you are that day)

On windy days, of strong thermaling days... you'll be glad your model weighs what it does. Belive it or not, sometimes you need to even add up 8 ounces of extra weight around the CG to get the model to penetrate some of these thermals. Some are too strong to even enter into without the extra weight. Gliders are a different animal than normal "powered" aircraft. In this one case, sometimes the extra weight gives you a better day at your favorite flying field.

I know alot of this dosen't make much sense, but... it's absolutely the truth.

Danoman...

aeajr

My Feedback: (2)

Danoman speaks truth, but of course we want to have weight under control.

That plane is targeted at about 40 ounces, I believe. What is your total weight with the plane balanced? What weight were you expecting?


What have you done to move weight as far forward as possible?

What have you done to keep weight from behind the CG?

Did you build it stock or have you modified it?

Weight is not always a bad thing. My 3M Legend weighs around 5 pounds. Flies great!

My 2M spirit is around 30 ounces, but when the wind comes up I add 3-8 ounces of lead to it to get better stability and wind penetration. That puts me up in your range.

Fly it, you'll like it!