What motor should I get for this sailplane? - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
Jul 18, 2003, 10:17 PM
Segelflugzeug esgeht nach oben
AllThumbs's Avatar

What motor should I get for this sailplane?

I have a Premier Graduate in a box and I'm anxious to build it.It can be built standard Rudder/Elevator for winch/hi-start or with electric power.

What motor/prop/speed control should I be thinking about purchasing?

I have a Jeti 35 speed control that works great in my E. conversion Olympic 650....but
the Master Airscrew flight pack is staying put in the Oly.
I may consider reusing this Jeti 35 - or a Great Planes Electrifly "soft start" on/off
switch, but I'm open to suggestions for new speed control/motor/prop/combos ).

Thanks everyone.
Here's the details on this sailplane:
96 inch Wing Span
800 Sq.In.
40 Oz. +-
Airfoil appears to be a flat bottom E205
The instructions in this kit suggested a Graupner #1165 System, 9.6V Speed 700 Turbo...ungeared, direct drive with a simple mechanical on/off switch operated off the elevator servo.
Blip it up for "on",
Blip it down for "off".
Sign up now
to remove ads between posts
Jul 19, 2003, 09:07 AM
Registered User
Zoomer-Ron's Avatar
Yikes, that must be an old kit. About ten years ago I built one for a magazine review. Powered it with the Speed 700 turo motor on eight 1000 mah cells and 12x6 prop. I flew it regularly for about 5 years, now it's up in the rafters in the shop.

It's a OK kit, with pretty awful instructions, but it should go together like your Oly. I used the ailerons, but it needed rudder coordination. It is a good floater design. The wings need a tight covering material to prevent flutter. The three wire wing rods worked like a charm. They allowed a lot of flex without putting a strain on the wing panels themselves.

These days I'd use a Jeti Phasor 30/3 or Mega 22/30/3 in place of the Speed 700 (especially since yopu already have the right speed controller). Use 7 or 8 cells of 1700 mah capacity, the fuselage was pretty narrow. A 12x6 prop would be a good starting place, but these motors can handle a lot more current draw than the old Graupner "can" motors.

Good luck

Jul 19, 2003, 10:08 PM
Segelflugzeug esgeht nach oben
AllThumbs's Avatar

Thank You Zoomer.

Nothing like the voice of experience and I'm All Ears on this one.

I'll be paying attention the wing flex now that you mentioned it.
I'm satisfied with the Olympic 650 E. so far, but I'd like to put a little more zoom in this next electric project.
I really wanted a Standard size sailplane and this one looks like a sleek polyhedral - in some ways like the Sagitta 900, but with turbulated wings like a Riser.

I got this one on ebay, don't see a date anywhere but it looks old.
Hmmm..yes, there is an aileron "option" - with mini servos on each wing tip, how about that!(Thanks for mentioning it).

Do you think I should go for ailerons? I have a JR xp783 that could probably do rudder/aileron coupling...(I think).
I got some good suggestions from this Forum on the Olympic 650 E conversion and it worked out pretty well for me in the end.

I did the first couple of flights recently on the Oly and got a 25 minute flight on the first launch.....without even really nailing a thermal, just ranging around the field.
So far, I'm enjoying my foray into electrics now that I have one flying.
Although the 2M Oly went from 5.5 oz./sq.ft. to 10 oz./sq.ft. and flew a lot faster with all the weight, I had some fun I want to tell you.
Last edited by AllThumbs; Jul 19, 2003 at 10:21 PM.
Jul 20, 2003, 01:05 AM
Segelflugzeug esgeht nach oben
AllThumbs's Avatar

On the Phasor 30/Mega 22 .......

The Jeti Phasor 30/3 or Mega 22/30/3.....

Aren't they sensorless/brushless motors?

I believe they would need a matching sensorless brushless speed control, would they not?

My Jeti 35 ESC is for can motors.

(But I'll check into the Phasor and Mega nonetheless).
Jul 20, 2003, 08:59 PM
Registered User
Zoomer-Ron's Avatar
I don't think ailerons are necessary on this plane. I remember the rudder being plenty powerful for turning. But I do like the ailerons for holding a bank angle or keeping the wings level on landing approaches.

Jeti 35 brushed controller, sorry I missed that. You are right, I recommended sensorless brushless motors. They are somewhat overkill on the Graduate.

Well, we know that the Speed 700 turbo works. If they are still being sold, I bet the price is pretty attractive. A geared Astro cobalt 05 would work well. You would probably want the planetary gearbox to keep the motor on the centerline. I don't think a direct drive "can" motor is enough.

BTW, I remember there being some plastic hatch material, but I substituted 1/16 ply, mostly so I could extend it a little further forward.

Jul 20, 2003, 09:12 PM
Segelflugzeug esgeht nach oben
AllThumbs's Avatar

So that's what that plastic sheet is for....

...you have a good memory.
I'll go for wood, what ever saves weight.
Got this thing on the building board as we speak.

Gads, it's all in metic...millimeters!
Every part I'll have to loook for in the box and check with a metric converter.

Don't see any 1/4" stock...but there is some 3mm x 6mm x 910 mm stock.
(This is going to take awhile).

Yep. Hobby Lobby still has a 700 Turbo (How about that....looks direct drive).

I'm still interested in that Jeti Phasor after reading about it several months ago. Overkill prehaps....think it would overstress the wings?

If anyone has used E or Motorcalc I would love to see a prediction with a phasor set up.
May 24, 2008, 12:05 AM
Registered User
Please help!! i am anewbee and have crashed my multyplex several times, it
porpoises very badly and i cannot control it,does this have to do with the battery to much one way or the other,[balance]? Strubedo
May 26, 2008, 10:35 AM
Registered User
Originally Posted by strubedo
Please help!! i am anewbee and have crashed my multyplex several times, it
porpoises very badly and i cannot control it,does this have to do with the battery to much one way or the other,[balance]? Strubedo
Hi Strubedo,

Why not start your own thread . This maybe an old thread, BUT it is still "hijacking".

BTW, Multiplex is a company (not a plane) that makes all facets of RC equipment. What plane are you attempting to fly? Have you had it checked by an instructor?