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Old 10-02-2018, 04:36 PM
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I am confused by the way numbers are used to discribe engine sizes. For example, what is a 120 size or a 190 size? I understand a 26cc or a 35cc but when it comes to 120-190 etc I don't get it. Why are these numbers used? And why would a plane be called a 40 or 60 size when they can theorectically use a larger engine? If one has the owners manual then choosing the specified engine size is easy, without this information one could concievably pick the wrong size. I have a DLE 35 and want to purchase a battery powered starter for but the information on this starter only states that this starter is for a 120 -190 size engine, this is where I am at a loss to knowing the correct starter which would match my needs. Any suggestions?
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Old 10-02-2018, 05:30 PM
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In your example, a 120 is 1.2 cubic inch displacement which would be 20cc. That being said, you will get mixed advise about using a starter on a 35cc gasoline engine. Personally I do not reccomend the use of a starter on any 2 stroke gasoline engine. When correctly adjusted gas engines are very easy to start by hand and are quite safe when doing so. Odds are that if your engine does not start easily then something is wrong that needs correction or your starting procedure is incorrect. If you can describe the issue you are having in as much detail as you can I'm sure some of the knowledgeable guys here will be able to give advise that will lead to a fix. Of course if a starter is needed due to physical limitations I would suggest a Dynatron starter with a large starter cone installed and run off a 4 cell lipo battery.
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Old 10-03-2018, 07:57 AM
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120, 190, 40, 60, etc are hundredths of an inch. We are still under the assumption the United States uses the inch system instead of the metric system. And the airplane size is the minimum engine size that is recommended - most people use a larger engine because they like to overpower their planes.
Electric motor sizes are another story. They can be anything including the size of the can and most mean little regarding what the motor can really be used for. You have to read the reviews to find out how useful any specific motor is.
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Old 10-03-2018, 12:09 PM
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In the old days, pretty much everything engine wise was marked/labeled in a fraction of a cubic inch. A .61 (often referred to as a 60 or 61 today) is 10 cc. From there you should be able to ball park any engine size from whatever it's labeled to something you can understand. Do the math!

So, a 120 is really a 1.2 ci or roughly 20 cc. My OS 320 is 3.2 ci or around 53 cc. And so on.

With the gassers and their Asian chain saw/leaf blower heritage, they were marked in cc. So your DLE 35 divided by 10 equals 3.5. Multiply that by the .61 ci that is 10 cc and you get an inch equivalent of 2.13 cu.

I personally prefer cubic inches. After all, Americans and their engines have always been about the Cubes! Even today my Harley has 103 on the engine vice the 1688 cc parts of the world think it is.
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