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Oct 31, 2010, 06:16 PM
i can't learn fast enough

gentle lady

Well a friend of mine just gave me a partial built GL.
Part of the fuse, is done, the Horizontal and Vert stabs are conpleted but not covered.
I was thinking of putting an E-flight 400 with a 1500 map and 2 9g servos'.
Not sure what prop to use?
I have some black and red monokote, would the colors be OK.
This will be my first glider.
Any suggestions and or guidance would be great.
Don't be baseful, heheheh
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Oct 31, 2010, 06:37 PM
Stick lift beats no lift
TexasJohn's Avatar

Gentle electric


Sounds like you are on the right path. I have the Sophisticated lady running on a geared long can 400 turning an APC 10-4.7 and pulling 9 amps/100 watts on a 3s lipo. Mine weighs about 1.5 pounds, so about 70 watts per pound. It is just about right. If memory serves the Eflight 400 will draw about 120 watts on a 10 inch prop, but that might be 9 inch.

I found I needed to open up and reinforce the bulkhead at the front of the wing so the battery would fit through, and cut away some of the canopy base for the motor. a 1.5 inch MPI aluminum spinner fits it very well.

If you search the gliders for sail, I mean sale for sophisticated you will find my plane. Need to close the thread since I really dont want to sell now.
Oct 31, 2010, 09:19 PM
B for Bruce
BMatthews's Avatar
Is this the motor?

If so then the suggested prop sizes given as examples would be where you should start. You'll want to find a prop in the 10x6 range that is a folder.

At a typical electric weight of around 30'ish oz a prop that forces the motor to pull around 9 amps from a 3S lipo pack will result in around 100 watts of power. That's a hair over 50 watts per lb. This will be enough for a moderate speed climb at around a 30 to 35 degree angle. You'd reach 400 to 500 feet in around a minute. If you prop it for a bit more current draw it'll speed up the climb but according to the specs on the motor there's not much more to give without it burning out.

Now TexasJohn seems to think it can pull an honest 120 watts without undue strain over the long term. This may well be as E-flite products do seem to be somewhat conservatively rated.

But you'll want to check this for yourself. A simple grass roots test to see if the prop is too big for the motor and battery combo is to ground run it at full throttle for about 50 to 60 seconds and then shut it off. Wait for 30 seconds for the heat from the inner core windings to seep out through to the outer bell. If at any time over the next minute to minute and a half the motor gets too hot to hold onto comfortably then I'd suggest that it is running too hot to ensure a long life for the windings. Keep in mind that the windings in the inner stationary core are obviously running hotter than you will feel on the outer motor bell. In that case reduce the prop size slightly and try again.

If it turns out that you manage to keep your model down closer to the same 1.5 lbs as TexasJohn then obviously your climb performance will be even better than it would be at the 30'ish oz mark. It'll also float like a dandelion seed. At the 26'ish oz that many pure glider GL's come out at the design is superb for calm to light winds. But if the wind gets up much above 5 mph then it becomes less and less fun to fly. By 10 mph you're in survival mode for the most part. But for a calm end of the day summer flyer you can't beat them.
Oct 31, 2010, 10:48 PM
Suspended Account
If you haven't got a motor yet, I would recomend this:

140 watts would give a better climb. However, if you manage the throttle you could even push crappy motors like an eflite beyond their rating. Keep run times down to 15 - 20 seconds and allow for a few minutes of cooling. Make sure you have an esc that can handle 30 amps or so. If you smoke the motor, just land.

The gl was the first glider I ever had back in the late 80s. I would push it really hard through some loops and watch the wing tips occilate. Traded it for a snowboard, I got the bad end of the deal.
Nov 01, 2010, 06:00 PM
Suspended Account
Terry, Himax makes a 200w motor that replaces the eflight. Check out MPI, maxxprod.
Nov 01, 2010, 06:46 PM
i can't learn fast enough
Thanks to all.
BMattews-- yes it is the mtr.
I think I will be able to use the e-flight, if not I have one just a little bigger, just can't remember the exact size.
Was wondering what a good combination would be for a folding prop w/ spinner, and related goods needed.
I was able to save the fuse., and wing, just figuring out the exact locations and install method for the pushrods, and the fuse is already sealed.
I only have 2 rolls of monokote, one red the other black. Which would be move visable on the underside of the GL.

Thanks much for the info, and your patience.
Nov 01, 2010, 08:40 PM
B for Bruce
BMatthews's Avatar
Definetly black underneath. However I would not suggest black for the fuselage. It'll get stupid hot in the sun during summer. Hot enough that it's uncomfortable to hold onto. I did ONE black fuselage plane in my days and it used to get so hot that I would bring a white towel to throw over it between flights. It was hot enough that I feared for the long term effects on the radio gear. A bit of black trim won't hurt anything but an all black fuselage is just cruel and unusual punishment for any electronics inside. Or perhaps black from the midline of the sides and down with red upper sides and top.
Nov 02, 2010, 10:41 AM
i can't learn fast enough
So if I do the top in red, and the fuse sides in red, and then all the underneath in black, inckuding the wing, it should be fine?
Or should I just break down and get another color or 2?

Any Ideas on the folding prop and spinner combo?
Do the spinners depend on the diam of the prop shaft? I hope not, and then I will not be able to change from different mtrs.
Thanks again
Nov 02, 2010, 11:12 AM
Suspended Account
Try this

I have been using the apc version and they seem to work well. You can get different collets for any size spinner.

I personally would go with a lighter color on top of the wings. Red looks black to me at a distance on over cast days or whenever the solar irradiance isn't just perfect. It makes it hard to identify the low wing.
Nov 02, 2010, 01:45 PM
Stick lift beats no lift
TexasJohn's Avatar
I think the 30 ounce range BMathews mentioned is closer to my plane actual all up weight.

If you stick with your Eflight 400 you should have enough power under light wind conditions. Expect the nose to point up with power on and be wary of a nose-up attitude near the ground

After you get your battery as far forward as possible (you will need it there with such a light motor) then mount servos and pushrods close, aft of batt. Any mount and pushrod within reason will work. Many like to put side rails along the fuse and a thin (1/32 or 1/16) ply sheet with servo cutouts mounted to the rails either with screws or glued. My pushrods are wire on elev and 1.5 mm CF on rudder, both in tiny plastic housings. Good anchoring of the housings at both ends will help reduce slop and that other bad thing..hysterisis ??

With such a small motor, you may be able to access the battery via the canopy opening. Sorry I cant recal if the GL has a removale canopy/hatch?
Nov 02, 2010, 07:57 PM
B for Bruce
BMatthews's Avatar
Truth to tell red and black would not be my first choices. When I suggested what I did it was intended to make the best of what you wanted to use.

I've found that transparent red for the wings and stabilizer works extremely well for my own eyes. On top of that a white fuselage and fin is second in brightness only to the reflective tapes and such. For me the white fuselage really stands out and allows me to see the persepective of the model and not just a silhouette.

For solid wing colors anything dark on the bottom and white on top with some of the dark bottom color as trim works nicely and again when low and far the white top and dark bottom really aid in keeping your perspective in tune as to the model's attitude and direction when it's really small.

And TexasJohn raises an excellent point on the motor and battery pack placement. Do work as much as you can to keep the tail light. Up front the last bulkhead that the noseblock of the glider glues to should be replicated in 1/8 ply as the motor mount and doublers added to aid in further hardening the motor mount since it tends to take a beating from landings. The cowl around the motor can be made from a hunk of clear hardware store spruce or even fir so it is tougher than balsa and puts at least a few grams up front where it'll help. And if you're making a new fuselage or don't mind splicing a bit onto the sides up front adding a little length to put the motor mount an inch further ahead wouldn't be a bad thing at all.

Texas, yes the GL does have a removable hatch. It's just a flat plate that sits in the top of hte nose and it's held trapped down by a finger of wood at the front and by sitting under the wing's leading edge at the rear.

Speaking of this hatch it would not be hard to make a new one out of some 1/2 or 3/4 sheet and hollow it slightly to give you a little bit of a "canopy" looking nose hatch and again to further add a touch of at least semi useful nose weight to the model. And such a hatch could extend over the first part of the wing to act as a bit of a nicer looking cover for the wing rubber bands. It would then also allow for removal to access the motor battery without needing to remove the wing as it works normally.
Nov 02, 2010, 10:01 PM
Air PLAIN Crazy

GL and Elec. Power

I have been flying my 4 year old G.L. on electric for almost a year ( about 60 flights.
I would not use less than 150 -160 Watts. My G.L RTF (ready to fly) is a bit over 30 Oz.

I use a 9 X 6 folder from Hobby Lobby Using the Turbo 42mm Spinner and
aero-naut blades. The motor is not critical as long as you can draw less than 18 Amps I think. Stationary mine shows 165 Watts and am using a 3S 1200mAh Lipo. You don't need an expensive motor.

Try to stay away from the geared set up - keep everything simple.
A Kv in the range of 1000 to 1400 is about right. I use motors ans BP hobbies has a good motor that won't make you go broke.

If this is your first glider, put the CG stock as per plan.

The 9 gram servos is goinng a bit light. For the G.L. I use Hitec HS81 servos.
Hey this is not one of those tiny foamies.
Nov 07, 2010, 04:13 PM
i can't learn fast enough


Thanks to everyone for your input.
I just picked up some orange and yellow for the GL, and changed the servos, to a little bigger ones.
I will check on the other mtr I have so see what the watt ouptput is.
I will try and get some picks and then seek more advice, if you all don't mind.
Thanks again
Nov 07, 2010, 05:10 PM
Who said Kiwi's can't fly!
Grunta5's Avatar
Hi Guy's, just my 2c worth on the servos... I wasnt sure about the 9gm servos either but have been using the HXT 900's now for about two years on my electric ugly sticks ( about 400w up front and about 100 flights) my 55 inch hot liner and 2 Wanderer sailplanes with no problems... I did replace one servo on the rudder in my electric stick , mainly because I occasionally knock the rudder putting it in the car , and it has a steerable tail wheel on it also .. I noticed it was developing a little slop or play... otherwise I swear by these little $2.99 servos

Nov 08, 2010, 12:17 PM
Suspended Account
I am running a generic 9g servo(HS 55 knockoff) on the rudder of a 3M e-conversion with a pull pull system. It was suppose to be a temporary thing, but it hasn't failed after a number of rough landings so it is still there. I have been rather suprised. I am sure if it was on a pushrod setup it would be shredded.

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