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Sig Komander electric conversion

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Old 11-02-2009, 10:48 AM
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LDreyfus
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Default Sig Komander electric conversion

I have been sitting on a Sig Komander kit for almost 20 years (!!) and I plan to start builing it this winter. I've been thinking of converting it to electric. Has anyone done this? The kit say i will build to 5 1/2 punds and recommends .40-.50 glow engine.
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Old 11-04-2009, 08:41 AM
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Default RE: Sig Komander electric conversion

Wow, a Sig Kommander! I had one of those in the mid-70's with a Fox 45 on it. Fantastic plane. Wish I could find a kit today. I don't know when they quit making them.

A quick look around leads me to a motor like this one. Jeff at HeadsUpRC gives lots of good advice here. I would think that if you build light and don't use too much paint, this should work fine. My Kommander was a lead sled, but still flew fantastic.

The biggest problem I see is battery access. Taking the wing off every flight is a bit of a pain, but that would be the simplest solution.

http://www.headsuprc.com/servlet/the...lectric/Detail

I'm thinking an 11x7 prop and 4 cells. Some serious power there.

Cliff
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Old 11-06-2009, 09:54 AM
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Default RE: Sig Komander electric conversion

Cliff,

Thanks for the reply and the information. I have 1 plane I'm finishing ahead of the Komander, but will probbaly start on it over the Christmas holiday. I can't wait. I'm glad I put it off, becaues I think it will make a terrific electric conversion candidate. I agree that keeping it light is going to be the trick. I don't have experience with sheated foam core wings, so I don't know if there is a significant weight differential between this design and a balsa built-up wing of comparable strenth. My sense is that the weight reduction can best be achieved in the fuselage. We'll see.

Again, Thanks for the info, the engince you suggested looks perfect.

Lawrence
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Old 11-07-2009, 10:17 AM
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Default RE: Sig Komander electric conversion

Lawrence,
It has been a long time since I built my wing, but I can tell you that the wing comes out VERY strong. I don't think the sheeting added much weight. Please post how things come out.

Cliff
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Old 11-07-2009, 11:02 AM
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Default RE: Sig Komander electric conversion

Cliff,

I definitely wil post the resultsl. I may even post a building thread! It would be my first. The Komander is such a classic, I think it would generate some enthusiam on the forum (provided I do a halfway decent job!!)

Thanks,

Lawrence
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Old 12-11-2009, 05:02 PM
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Default RE: Sig Komander electric conversion

I assume your going to build it as a trike? If so you will most likely be limited to say a 12" prop, give or take.

If you want to go 5S the E-Flite Power 46 will make over 1 KW of power on 5S with a 12x7E prop. Flys a Kaos very well.

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Old 12-12-2009, 01:23 PM
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Default RE: Sig Komander electric conversion

Got some good info on this thread. I am finishing a Goldberg Eagle 2 that a friend gave me an decided to try to convert it to EP. I went to the Heads Up RC site and learned everything I wanted to know. Now I just have to buy the stuff. I live in North Idaho and am looking for a plane other than my slimers to fly on a cold sunny day.
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Old 09-10-2019, 10:54 PM
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How did the electric conversion go? I have this kit and will be assembled by an experienced builder. It will be electric powered with a Power 46 as well. What size battery did you use? Do you have photos of where and how you located the ESC and Battery in your plane. Thank you for any information you have.
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Old 09-12-2019, 01:47 PM
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Ignore engine<>motor cubic inches equivalencies, they restrict your choice of motors needlessly. Ignore shops that try to advice you that way, they don't know their business.

Plane type and mass are leading when choosing power. See quote below.

Planes don't care about voltage, they care about power though.
Choice of voltage mainly depends an what you already have, and on what equipment is available.

Below an excellent quote about motor selection.
From
brushless motors Kv?.
Originally Posted by scirocco View Post
While an absolutely critical part of the system ...
... Kv is actually the item one should choose last.
  1. Decide your peak power requirement based on the weight of the model and how you want to fly it.
  2. Pick a preferred cell count (voltage) and pack capacity for how to deliver the power.
  3. Pick a prop that will a) fit on the model and b) fly the model how you want - often as big as will fit is a good choice, but if high speed is the goal, a smaller diameter higher pitch prop will be more appropriate.
  4. Look for a size class of motors that will handle the peak power - a very conservative guide is to allow 1 gram motor weight for every 3 watts peak power.
  5. Then, look for a motor in that weight range that has the Kv to achieve the power desired with the props you can use - a calculator such as eCalc allows very quick trial and error zooming in on a decent choice. For a desired power and prop, you'd need higher Kv if using a 3 cell pack compared to a 4 cell pack. Or for a desired power and cell count, you'd need higher Kv if driving a smaller diameter high speed prop compared to a larger prop for a slow model.

The reason I suggest picking Kv last, is that prop choices have bounds - the diameter that will physically fit and the minimum size that can absorb the power you want. On the other hand, combinations of voltage and Kv are much less constrained - at least before you purchase the components.

So Kv is not a figure of merit, in that higher or lower is better, it is simply a motor characteristic that you exploit to make your power system do what you want, within the constraints you have, e.g. limited prop diameter, if it's a pusher configuration, or if you already have a bunch of 3S packs and don't want to buy more, and so on.

Minor lay-out changes by RvS
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Old 09-15-2019, 03:55 PM
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Originally Posted by LDreyfus View Post
I have been sitting on a Sig Komander kit for almost 20 years (!!) and I plan to start builing it this winter. I've been thinking of converting it to electric. Has anyone done this? The kit say i will build to 5 1/2 punds and recommends .40-.50 glow engine.
Do you have any photos of your SIG Komander electric conversion. Where did you put the ESC, the battery access. What size motor did you use? Did you build a bottom hatch for the battery or use the top hatch?. Please advise of any modification you made for your electric conversion. Thank you.

Francois
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