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EMP Apex 98" How do I convert to Electric?


Stuart Z
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I bought one of the above at the Sandown Expo m-a-n-y years ago.  I would like to put an electric motor on it, not the over wing pod type.  

 

How do I set about it.  No doubt a bit of maths needed.  New to gliders so all a bit of a mystery at the moment.  

 

Hope you can help.

 

S

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I've just acquired an unstated kit of the 98" Radio Sailplains Sirroco from the same era. I did build one back in the 70's together with the Wildfleken. Back then I had a pod with a small glow engine but like you, Stuart, this time I'm intent on electric in the fuselage.

 

You can be quite crude & bolt something like a 3542/900Kv motor on the nose with a 12x6 on 3 cells & it should perform OK.

 

I'm looking at something a bit more elegant by burying the motor in the fuselage. There is not much room so a hybrid or a geared out runner look favourite. I've a couple of geared Hackers in flying wings which go well. I also like Axi motors & have narrowed it down to either:

 

https://www.electricwingman.com/model-motors-axi-280824-cyclone

or

https://www.hacker-motor-shop.com/Brushless-Motors/Typical-gider-drives/Glider-3kg/A20-6-XL-10-Pole-EVO-kv2500-4-4-1.htm?shop=hacker_e&SessionId=&a=article&ProdNr=97800029&p=7201

 

Neither is a cheap option but either should be just about invisible in flight with a folding prop.

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Thanks for the input folks.  It is a glass or similar fuselage but I do fancy the idea of an internal motor.  Just wondering how to assess the cut.  Not keen on keeping it for bungee or tow launches as I’d rather be lazy and launch from a standing position.  No longer built for hurrying around a field.  I have an Ares Alpine which is great fun and wanted to do something similar.  Already have a RES Eagle and motor in the queue.  Found the Apex in the loft and was looking how to go about putting a motor in that as well.

 

S

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That's a big glider for a 2s battery, you will need around 150 Watts I guess as a minimum, I'm guessing around 1.5kg flying weight? The Eagle is about 550g flying weight? 

If you do use a 2s battery it will need to have a fairly high capacity, a 1.3Ah battery will get you about 3 minutes powered flight but would probably be too big to be used in the Eagle as well so it may not be possible to have interchangeable batteries. 

I'm building an electric res glider using a wacker geared motor and a 3s battery, 0.45Ah for weight saving and it will give me 2 x 30 second runs for competitions, may increase the capacity a bit if it's tail heavy, battery weight more useful than lead. 

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Thanks Shaun

Very good info, when my back let’s me I’ll try and get back in the loft to have a look and get some weight.  Being ARTF it will be a good guide straight out of the box.

I’ll also have to get into the maths of electrics.  Used IC most of the time so what motor or battery works, I’ve never thought about.  The size and space will probably allow a 3S set up but when I get it out I’ll get a better idea.

I appreciate your help so far.  I’ll revert in a couple of days.

S

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Rather than hack an ARTF fuselage around for a motor it might be easier to make a new fuselage to use the wings.  Then you could revert to a glider again if required.  

 

The 4Max website has lots of info on setups for different models although not many large gliders.  Lots of other info there too.   An email to 4Max should get info on suitable motor setups if you specify weight and size etc.

 

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  • 3 weeks later...

Correct, iirc, it was a 540 can motor on the fin with a bit of a fairing and a 7 cell SCR pack under the wing joiners. 

 

A neater way to go might be a power pod secured over the wing dowels like the one for the MFA High Sierra. A 3 or 4S Lipo would go in the fuselage between the wings, bring the wiring for the motor out through one of the extra holes in the fuselage side and run it up the leg of the pod. 

 

Folding prop, possibly 11 x 5 or something. 

 

 

 

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Thanks for the continuing input folks. 

 

I know a power pod was the design option, it is illustrated on my instruction sheets.  I wanted to hide the motor if possible.  The article by Chris Williams sounds like it may be of help.  Does anyone know where the Chris Williams article can be found?

 

Many thanks

 

S

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