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How to convert an ic to electric?

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SIMON CRAGG14/10/2019 12:10:04
482 forum posts
15 photos

I have a Hobbyking PT-19 which I would like to convert to electric.

Weight with ASP.120FS = 4472 G

Weight of engine = 890 G

Ideally, I would like the same power from an electric motor if that is possible.

Does anybody know where I can find a comparison guide, which would tell me which electric motor equates to a 120fs?

RC Plane Flyer14/10/2019 12:18:10
655 forum posts
19 photos

Hi Simon I see lots of people advising to speak to 4 max for some guidance

( I have no link to this company only respect for help provided in the past )

DDH14/10/2019 12:45:02
35 forum posts
2 photos

1 hp = 750 watts approx

**LINK**

4Max link: **LINK**

Nigel R14/10/2019 12:49:13
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3109 forum posts
479 photos

Wet finger in air - about 1500W.

**LINK**

5055 430kv motor

6S lipo, around 5000mAh capacity

17x10 prop

80A ESC

Peter Miller14/10/2019 14:05:19
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10271 forum posts
1226 photos
10 articles

If you have to ask (I always DO!) phone 4-max.

I have no connection with 4-Max apart from being a very satisfied customer. Their phone number is on my phone!

Edited By Peter Miller on 14/10/2019 14:05:55

Edited By Peter Miller on 14/10/2019 14:07:06

Chris Walby14/10/2019 15:14:24
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1003 forum posts
236 photos

One consideration is how oily it is as it will make modification more difficult/extensive to the wood work.

At some point it would be easier to move the model on and start with fresh balsa smiley

Richard Wills 214/10/2019 15:39:09
avatar
178 forum posts
7 photos

I have converted a p-47 that had an asp 120 on it, and used the following which gave an approx equivalent power

5055 430KV

6s 5000 mah Pack

16x10 prop. The 17x10 gives way more thrust than the ASP ever could, the 16x10 is more similar, 15x10 was not very much less power than the glow flight time obviously increased as the prop size goes down.

Nigel had it pretty much spot on

SIMON CRAGG14/10/2019 16:06:56
482 forum posts
15 photos

Thanks chaps, think I will go for the 15 x 10 prop (where is the best place to get these, as my props are ic and much finer pitch?). I will only be flying it in a scale like manner, so presumably a 6s 4000 would be ok to start with? Also, I was going to fit an 80amp ESC, does that sound right? Big step after over 40 yrs ic!!.

Richard Wills 214/10/2019 16:24:54
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178 forum posts
7 photos

Simon I am mainly IC, so the easiest way I have found for me is to calculate the approx rpm from the motors KV and cell count of the pack to be similar to the IC engine it is replacing and then start with the same prop. the 430kv on 6 cells under load in practice gives about 8500rpm, so about the same as your 120 fs if you were running say a 15x8. What prop have you got on the 120 now?

SIMON CRAGG14/10/2019 16:42:55
482 forum posts
15 photos

Richard, just sent you a pm.

16 x 6 Master at present.

Edited By SIMON CRAGG on 14/10/2019 17:04:42

Tim Ballinger14/10/2019 18:39:31
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557 forum posts
229 photos

+1 for asking George at 4 max. Fast and in my experience usually spot on.

i also have and use Ecalc which also seems pretty accurate . Just google and download. There is a free version but the full job is not that expensive .

Tim

SIMON CRAGG14/10/2019 20:04:03
482 forum posts
15 photos

Well that's done it! Just sent for all the items I think I need to convert the model to electric. Exciting stuff!

Outstanding help from you guys as always.

Allan Bennett14/10/2019 20:22:09
1555 forum posts
39 photos
Posted by SIMON CRAGG on 14/10/2019 16:06:56:

. . . I will only be flying it in a scale like manner, so presumably a 6s 4000 would be ok to start with? . . . .

Remember, a different size/weight battery will move the c of g, so your battery bay needs to be able to accommodate a range of battery positions so that you can always position the pack to give you the right c of g. In my experience, all my glow-to-electric conversions require plenty of weight up front because the electric motor is lighter than the engine it's replacing, so don't go too small/light with your battery.

SIMON CRAGG14/10/2019 21:12:13
482 forum posts
15 photos
Posted by Allan Bennett on 14/10/2019 20:22:09:
Posted by SIMON CRAGG on 14/10/2019 16:06:56:

. . . I will only be flying it in a scale like manner, so presumably a 6s 4000 would be ok to start with? . . . .

Remember, a different size/weight battery will move the c of g, so your battery bay needs to be able to accommodate a range of battery positions so that you can always position the pack to give you the right c of g. In my experience, all my glow-to-electric conversions require plenty of weight up front because the electric motor is lighter than the engine it's replacing, so don't go too small/light with your battery.

Thx for that Allan. The battery bay is enormous and could take four 6s packs. The 120 was a very heavy engine so there may be a bit of jiggling about to be done!.

Erfolg14/10/2019 21:52:02
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11396 forum posts
1209 photos

The motor is one obvious issue, the next not so obvious, yet sometimes harder to solve is both the Lipo storage and then arming and disarming the model.

wp_20170228_09_51_04_pro.jpg

This my PT 19, a converted Stirling kit.

In my case i have arranged for the upper part of the front to be removable. In many ways this has been my easiest conversion. Although my conversion strted as a bundle of bits of balsa, if partially built it could be harder to do, without incurring a lot of work.

Julian Murch15/10/2019 08:50:14
35 forum posts
1 photos

There is of course an article about electric conversion in the recent RCM&E Special Issue.

Attilio Rausse15/10/2019 09:05:55
105 forum posts

Hi Simon

Just seen this post, I also fly the HK Pt-19 with an electric setup, I use a 5065 236kv up front for weight and reach (the cowl is very narrow at the front). Again, for weight I used a 12S setup (2 x 6S 3300) HV ESC mounted right up front. Don't know which battery you've gone for but with 6S you'll be drawing 70A at full throttle which will be pushing the limits of the motor.

Please keep us up to date with progress, I can provide photo's if required.

Til

SIMON CRAGG15/10/2019 13:49:54
482 forum posts
15 photos
Posted by Attilio Rausse on 15/10/2019 09:05:55:

Hi Simon

Just seen this post, I also fly the HK Pt-19 with an electric setup, I use a 5065 236kv up front for weight and reach (the cowl is very narrow at the front). Again, for weight I used a 12S setup (2 x 6S 3300) HV ESC mounted right up front. Don't know which battery you've gone for but with 6S you'll be drawing 70A at full throttle which will be pushing the limits of the motor.

Please keep us up to date with progress, I can provide photo's if required.

Til

Hi

Many thanks, just sent you a pm.

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