gas to electric conversion help needed. - RC Groups
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Sep 10, 2001, 02:11 PM
Registered User

gas to electric conversion help needed.

I am a newbie building an Eaglet50 balsa trainer. Should weigh about 54 oz in gas trim. Any advise on motor, prop, servos, r/c, and batterys? I plan to use a 3 channel xmitter I have used on a Zagi wing. Looking for steady park flyer type of performance not 3d aerobatics. Thanks for any help. mflann.
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Sep 10, 2001, 02:36 PM
Mitch G's Avatar
What's the wingspan and wing area for the plane?

Sep 10, 2001, 03:03 PM
Registered User
columbiarcdude's Avatar
The Goldberg Eaglet 50 is a very good trainer/sport flyer. I'm sure you'll like it a lot. Be sure to keep the weight as low as possible. A Kyosho Magnetic Mayhem motor (reverse) with a Master Airscrew 3 to 1 gearbox and a MAS 11-7 or 12-8 prop should work great. I'd use at least an 8 cell 2400 mah battery pack too.
Sep 10, 2001, 03:08 PM
Registered User
It's a 48" span high-wing trainer.

Basic inputs: you need 50W/lb to fly, including the weight of your batteries, etc.

It will fly on a Magnetic Mayhem on 8-10cells geared... I don't have prop/gearbox recommendations for that powersystem, though... You should figure about 30A to get enough power to ROG.

to REALLY perform, get an ASTRO-15G, 14 cells and 11X7 or 12X8 prop.
(I have this plane and it works really well)

I converted mine to a taildragger to save weight, but it won't matter much.

One thing to do, though: If you haven't covered the wing, glue in additional shear webs... (Square pieces set vertically between the ribs, against the top and bottom spars). Double them up across 1/2 the span. I ALMOST folded my wing due to the extra weight! (I noticed an unusual amount of flex in the wing during a loop and cut the monokote to take a look... every shear web had cracked!)

Sep 10, 2001, 04:17 PM
Registered User
Thanks,folks. The wing is 8" x 48" which is 384 sq. in. The box says 450 sq in so I guess that includes the empanage? Two votes so far for the Magnetic Mayhem motor. Hey,columbiarcdude, what do you mean by reverse when you describe the motor? Thanks to Spam for the tip on adding wing shear webs. I haven't covered yet. Speaking of wings mine is not balanced port to starboard. the balance point is about an inch and a half to the left side. Should I try to weight the wing to compensate? All the dimensions measure evenly on each side. Spam, if I use the Astro-15g do I need a gear box or is direct ok. Also I know that for a given motor weight and performance are inversly proportional. If I add the wing shear webs do y'all have any suggestions about other areas for weight reduction?
BB manners question: Should I post all to the BB or reply to each via personal email? Thank again.
Sep 10, 2001, 04:32 PM
Registered User
Lot of questions :

Reverse means it's timed for using a gearbox. Direct drive timing is different.

The Astro 15G is geared. That's what the "G" means.

Please keep posting to the forum. If you go to email no-one else can see and get any benefit from the answers you get.

Sep 10, 2001, 04:57 PM
Registered User
Alan W's Avatar
Originally posted by mflann:
Thanks,folks. Speaking of wings mine is not balanced port to starboard. the balance point is about an inch and a half to the left side. Should I try to weight the wing to compensate? All the dimensions measure evenly on each side.
ABSOLUTELY balance left to right !! While not as important as having the CG correct, a Heavier "Side" will require compensation by trim settings - So, a wing that is built straight but not balanced may need aileron to compensate and fly level. This will cause un-needed drag and the plane will not fly up to its full potential.

final balance once everything is completed but uncovered. put the wieght as for out to the end of the wing as possible - the farther out the less you need = the better it will fly.

hope this helps

Alan W
Sep 10, 2001, 06:48 PM
Registered User
slewin: ok on posting. alanw: thanks I'll balance the wing and again before covering.This forum is great! Hope y'all don't mind if I ask for more hand holding as the project goes on. this is my first built kit. I did a zagi 400 with one of my sons and it flies well between crashes. thanks again.
Sep 10, 2001, 08:03 PM
Senior Member
Paul Penney's Avatar

feel welcome to post ANYTIME anyplace, or at least that applies to me