Whats in a Number

[cptozzy]

What makes a "120" a 120 ? Whats the difference between a 300, 450 or 500 How do they come up with the numbers?

[windwizard]

Here is some general info a guy gave me,

This is a can of worms !!

The 500 size is the same as 425 rotor blade. the two seem interchangeable for some reason.
originally the term came from the size of the brushed motor that would fly it, but this is so out of date is isn't true..

so lets start at the start.

These are the align models insert T-Rex before each one.
100
250
450
500
550
600
700

100 to 500 refers to motor size as it was in the stone age.

550 and up refers to the blade size so a 550 has 550mm blades and is the same size as an old school .30 nitro.
600 is a .50 size with 600mm blades and 700 the same .90 size 700mm blades.

the confusion really sets in when the manufacturers come up with other naming conventions. gaui 200 x5 etc.. thunder tiger e325, logo 500 etc...

now basically I look at the specs and see what length of blade the bird runs and then come to my own conclusions unfortunately the align models are pretty much the benchmark for most conversations so you will hear the 500 and 450 terms bandied about more than my 325 heli.

anything with 550 and up rotor blades is a size that you used to see in nitro.

but don't be fooled a 500 size bird is a lot smaller than a 550. the same goes for 500 - 450 it is a big jump in size.

it is becoming a lot more clouded with high voltage setups being used in smaller helis these days but a look at the specs should tell you roughly how big a helicopter is, if it runs on 6s 5000, 3s 2200 you can quickly get an idea of the size.

there are no hard and fast rules and it drives people insane but we are stuck with it until the manufacturers agree on a universal naming convention.

i hope this helps



Wiz

[KRYPTO316]

Very well said.

[rojack]

...and so, as you'd imagine, a Blade or Walkera "120" is likely to be a bit larger than an "Align T-rex 100", and smaller than a "Blade 130 X".

...but there is no official standard for naming these, other than what windwizard said, where there is a comparison made to existing Align T-rex models, nitro motor sizes, or blade length in millimeters.

For example there are several helis billed as "370" or "400" size, which are a little smaller than an Align T-rex 450, and larger than the "T-rex 250". The manufacturer most likely chose the number for their marketing purposes.