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Apollo EP-5 ARF Sailplane

TooJung2Die

Active member
#1
I picked it up at a flea market last summer. I normally wouldn't look twice at an ARF but it is all balsa and ply and too cheap to pass up. It has a 72" wingspan and a hefty AUW of about 3 pounds. I can't find anything about this Taiwan made airplane on the web. At all. I've looked and looked. It's an old electric judging by the motor that comes with the kit. I was able to identify the motor because they're still available. Suggested use is an electric drill motor. Hmm, that's an odd choice.

IMG_0264a.jpg

Kit contents:
IMG_0267a.jpg

DC brushed motor:
IMG_0266a.JPG

Seems to be a heckuvalotta of motor for the 7" folding prop it came with. Motor weighs almost 1/2 a pound! At least it gives you a clue to what size brushless motor to use.
jon.
 
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TooJung2Die

Active member
#2
Let's get started.
First thing to do is fix the covering film. It sagged and some edges peeled up over the years as it sat in the box. It has an unusual PVC covering film. The manual warns in big bold letters, "Do not use a covering film iron for any reason on PVC covering film!" It says only use a heat gun. They're right about the heat gun when shrinking the open film areas. First the film sags and then it slowly tightens up. It gives off a smell I remember but can't quite place. I got one wing tightened up without burning the film.

Wing before:
IMG_0775.JPG

Wing after:
IMG_0778.JPG

The heat gun was no use where the film edges were peeling up or bubbled over sheeting. I had no other choice but to try the iron with a hot sock. With the iron set to medium heat I was able to stick down the loose edges. It worked to flatten out some bubbles on the wing sheeting and the fuselage. No damage done with the iron but it takes a while for the film to shrink after it goes through the sagging stage.

jon
 
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Joker 53150

Mmmmmmm, balsa.
Mentor
#3
AUW of 3 pounds? Sounds like it's made of lead! :) I wonder if you'll end up needing tail weight after replacing that big lump of motor. Maybe shifting the battery forward will compensate for the lighter weight components available today.
 

TooJung2Die

Active member
#4
The manual says AUW is 1350-1450 grams. Weight of the airplane parts without the motor, battery, electronics, etc: 2 lbs. I haven't even started looking at motors for it yet. Since it's a sailplane do you think I can use less than the 100 watt per pound rule of thumb? I'm baffled by the 7" propeller in the kit. It looks a lot like the one on my Sunbird and that weighs under 1 pound. Is that really enough prop?!

I'd like to use a motor that mounts behind the firewall like the chunky drill motor it came with. Suggestions and sources are welcome and encouraged. (y)
 
#5
So many motors to choose from! After searching a while my head is spinning. I never had an airplane this big and heavy so I have no experience. Most of my airplanes are well under a pound. I like the "Heads Up RC" site because they group motors by watts, airplane size or motor size designation. I'm almost ready to place an order for this motor. Leopard 2835/6T 1350KV Outrunner Brushless Motor

Leopard 2835-1350kv.jpg

Comments?
jon
 

rockyboy

Skill Collector
Mentor
#7
So many motors to choose from! After searching a while my head is spinning. I never had an airplane this big and heavy so I have no experience. Most of my airplanes are well under a pound. I like the "Heads Up RC" site because they group motors by watts, airplane size or motor size designation. I'm almost ready to place an order for this motor. Leopard 2835/6T 1350KV Outrunner Brushless Motor

View attachment 123790

Comments?
jon
I've got a Leopard motor from them on my Easy Stick 40 and love it - great motor without killing your wallet.

Looks like the size you've got there will be plenty for a 2 pound plane.
 
#8
Looks like the size you've got there will be plenty for a 2 pound plane.
I think you're right. That's the motor. I don't expect to achieve unlimited vertical flight. A healthy climb is the goal. The only parts I have on hand that can be used are the receiver and servos. Too bad Heads Up RC doesn't sell folding props. All my props fit 3mm motor shafts and the Leopard motor is 4mm. I won't know what size battery to buy until it is known much ballast is needed to make up for replacing the heavy motor and NiCd battery.
 
#11
I am fortunate to have this vendor in my town I order online skip the shipping by picking up on the way home. If I had not checked on the location of RMRC, I would not have know that they we available for local pick up. Fly On~!