which outrunner for graupner speed 600 geared 2.8/1

[NIGEL CASTLE]

Can anyone suggest an outrunner that will give a simalar out put to a Graupner Speed 600BB geared to 2.8/1

 

I want to replace this brushed motor with a brushless outrunner in a sailplane with an AUW of 1800grams.

 

What I am looking for is a good climb to height, not aerobatic performance, would like to use the existing prop 5mm shaft 14" x 8"

My battery selection could be either 2,3 or 4S, escape to match as required.

 

If someone can suggest a good motor that will not break the bank.........

 

Many Thanks

[ken anderson.]

hello nigel---i would suggest a 300 watt outrunner will give you more than enough power for watt you need...you will need to use a different prop...the motor will prob cost around about £20.00.....you will also need a controller(brushless)...as a starting point check out BRC Hobbies web site they do combo's...motor/controller for reasonable price's.....

 

 

ken anderson ne..1.

[Erfolg]

There is no one answer to your question.

 

There are a number of ways of approaching the question. Also any sound based replacement brushless system will provide an improvement in performance. Be the measure rate of climb or duration, as brushless motor systems are more efficient with the same energy.

 

Although many work on the 200w per kg rule, for gliders the rule can be amended to 100w per Kg, with a commensurate reduction ultimate climbing ability. I have a model following the 200w rule, where the climb is absolutely vertical. I have others on the 100w rule, which climb out with a degree of vigor, compared to a 600 model, lethargic compared to what is possible.

 

I suspect you may have to ditch part or all of your propeller. I have not seen any brushless with 5mm dia shaft, of course they are bound to exist, but not in any great number.

 

Out runners are generally considered the best if a large dia propeller is to be driven, with a low Kv, if there is the room to instal the beast. My own 600 appears to be 35-36 dia. On that basis many motor suppliers often describe the motor dia by the first two integers so a 35xx, is often a motor with a 35 dia case.

 

There tends to one problem with outrunners and that is getting the three motor wires from the motor to the ESC conveniently.

 

As an aside most inrunners will require a gearbox, although HK do high torque inrunners

[Andy Butler]

Nigel,

 

I'm currently building an Apollo, 91" span V tail designed for a 600 motor. I'm using a 3550 900KV which does have a 5mm shaft. A whopping £16 odd from the big fish shop.

It is slightly smaller than the 600 and the weight is about the same so shouldn't have any CG problems. I did try an outrunner (3542 1000KV) but I couldn't get the wires past the rotating can without rubbing. I only tried it on an 11 x 6 folder and got 225 watts at 20 amps so with a 12 x 6 you should be able to get 300ish watts I would think.

Hope this helps.

[Erfolg]

Yep

 

you are right, the first HK outrunner I looked at was a 5mm shaft, Turnigy G15, then the next outrunner.

 

I then looked at my own recent purchase an E-Power 2815 also 5mm shaft.

 

So it does seem the exist , probably in greater numbers than I at first thought. I do suspect that motor shafts are generally increasing in dia across the range. Probably as a consequence of complaints, with respect to bent motor shafts.

[PatMc]

Nigel, I did almost exactly what you're asking with my O/D 2.7m model, RelaxE. It started by being powered by 8.4v nicads, a Lightspeed 600 motor with a Master 3:1 gb driving a 12x8 prop. It now uses 3s 2300mAH lipos & a Keda 36-12L driving an 11x8 prop. AUW with the original was 1814g now is 1558g climb & duration are vastly better. I used the 11" prop in order to limited the current taken to about 30A & use a timer on my Tx to limit the total accumulated power run time as the ESC is a pre-lipo.

 

Both the lipo & motor were bought from Giant Cod. This motor I'm using -

http://www.giantcod.co.uk/a3612l-1000kv-brushless-outrunner-p-172.html

 

Message to mods - I've tried to provide the link using the approved method but when I try I'm getting a message telling me that I'm forbidden access to that area, perhaps it's because I'm recommending a power source that doesn't have any soul.

Oh dear, it seems smilies are also off limits.

 

Above is RelaxE in brushed motor mode

 

This is after conversion to brushless - nose has been lengthened.

Edited By PatMc on 08/09/2011 15:07:25

[Erfolg]

With respect to motors my 2m Sagitta has had a number of inrunners, satiating out life with a epicyclic gearbox and inrunner and motor. This I destroyed by abuse.

This was replaced with a second inrunner, which was under amped.

So was replaced with one of these 480L.

 

This motor pulls 260w, and takes the model up quite well.

 

The first picture below shows the original motor and gearbox, with the replacement motor.

The second the finished job with the 3rd 480L motor.

The final picture shows a Sagitta with inrunner close to the camera and far Sagitta is with a outrunner. The front end became far chunkier.

 

There are photos of how i installed the motors, as the very front of a Sagitta is a Pine block, with 1/8" ply sides. I glassed the outrunner model to improve the strength. The nose on a Sagitta is extremely narrow and fine, causing problems when converting to electric.

[PatMc]

The outrunner in RelaxE uses an "X" mount on to the front bulkhead so that the wires are at the rear. When the motor was in position I constructed a cowl from thin ply & balsa around it.

[NIGEL CASTLE]

Thank-you chaps, I will look at all the above mentioned options further over the weekend, it sounds like i'm not alone in updating older models to new technology.

I'll keep you all posted as to how I go on..........

[Erfolg]

Nigel

 

You are certainly not alone, although there are some limitations.

 

Competition gliders of the past, are over sparred, to take very high towline and the ping forces. They are possibly as strong as today's moulded wings. The big difference is the weight of the wings, probably twice that of a moulded wing and the lack of accuracy and smoothness of the wing section.

 

The other debatable issue is body strength, the old competition gliders were made for dorking, or forcing down into the landing circle. Particular where no air brakes were permitted. The bodies immensely strong, but relatively heavy by all the standards of today.

 

Once up though, these older gliders can hold there own, particularly in a good breeze or stronger, where the heavier wing loading +10oz ft^2. I guess why it has taken so long is waiting for the high powered motors at low weight and Lipos (better power density compared to Nicads).

 

One issue I have had is the even Lipos can be difficult to get into the body, as the cross section was normally minimised to that of the servos cross section and a minimum section Nicad for the Rx.

 

Do able, as I have done my EMP Algebra and a bigger sagitta.