Help to identifiy gear ratio on a 600e

[shamen222]

How do you find out (figure Out) the gear ratio on a razor?

I bought a used razor and would like to tear it down and rebuild it. It has a few well loved parts that need to be replaced, but I would like to learn as much as I can about how it works first. Since I did not do the build on this and I am unsure of what the original owner did with it,(or ordered) my question.

I mean since its got the motor main gear, down to the pulley, the belt, back up to the main gear and so on. I am trying to check out what this razor is built with and I do not know where to start. I know its a hacker 16s, with a CC85, 3700 lipos and that means the suggested gearing is 8.1 or 8.4 but that may not be the case if someone got tinker happy, is there a way to find out? or do I just have to take the pieces off and start counting teeth?

I have ask others in a PM that Owns a RAZOR and they thought it best to post here. I have scoured the forums but I have yet to find the answer. I will be using the VERY detailed instructions to rebuild the heli so that should not be a problem.
I am very Green to this hobby but I think that this Heli is more than any Noob could wish for and I will try not to cut my own head off with about 1200mm of spinning death.

It is not to often that when a person invests in something they invest in the best. I feel I have done so in the Razor600e.

Regards,
Shawn

[mudbogger2]

start counting teeth?

If you don't know the ratio this is the only way to find out.

[shamen222]

How do you find out (figure Out) the gear ratio on a razor?

Let me put it this way, I would calculate ratio by taking the teeth on the motor gear and divide that by the teeth on the main gear- 100 teeth main/10 tooth motor = 10 gear ratio. so I know to start counting now, then what.

[jrohland]

Hey shamen222,

I finally had a few minutes to cogitate on this one. Why don't you put one end of your flybar parallel to the tail boom, put a mark (or some tape) on the motor pulley and, start turning the motor pulley until the head makes one full revolution. Count the number of turns the motor pulley made and, estimate the amount of the final rotation.

If you believe the ratio is 8.4/1, the motor pulley should turn almost 8 1/2 times with one turn of the main rotor. If 8.1/1, it will turn just over 8 turns, etc...

jrohland

[shamen222]

That makes sense.
I have been thinking about this alot and I think I may have figured it out.
On the razor it goes motor down to pulley, belt, pulley, up to what should be the final motor pinion and onto the main gear.

So Jroh tell me if you think this is right.
Working backwards from the MA web site. 8.4 to buy the kit is a 28-20 I can only think this is the size or teeth for the two lower pulleys. 28/20 =1.4. Now if the final motor pinion is 15 tooth 15/1.4 = 10.71. 90/10.71 (the main gear) =8.4
I think I am doing this right. For some reason I was concerned about the 75tooth belt as if it had any thing to do with it.

Now my next question is could you not just change the the final pinion to a 13 tooth or whatever to change the ratio as well as the pulleys?

[jrohland]

That makes sense.
I have been thinking about this alot and I think I may have figured it out.
On the razor it goes motor down to pulley, belt, pulley, up to what should be the final motor pinion and onto the main gear.

So John tell me if you think this is right.
Working backwards from the MA web site. 8.4 to buy the kit is a 28-20 I can only think this is the size or teeth for the two lower pulleys. 28/20 =1.4. Now if the final motor pinion is 15 tooth 15/1.4 = 10.71. 10.71/90 (the main gear) =8.4
I think I am doing this right. For some reason I was concerned about the 75tooth belt as if it had any thing to do with it.

Now my next question is could you not just change the the final pinion to a 13 tooth or whatever to change the ratio as well as the pulleys?
The length of the belt is not a factor in the ratio.

The ratio between the pulleys is actually determined by the circumference of the two pulleys. However, the number of teeth can be used as a proxy for the circumference. So, counting the teeth on the pulleys will work.

The ratio between the counter shaft pinion and the main gear cannot be changed. If you look at the frame, you will see the counter shaft bearing blocks cannot be moved forward or backward. This indicates the pinion and main gear are fixed in size. So, their ratio is set at the factory.

The only way to change the final drive ratio is to change the size of the two pulleys. When you change the pulley sizes, you may need to change the length of the belt because the motor can only move a short distance fore and aft.

Your math appears to work fine. Calculate the ratio of the main gear and counter shaft gear: 90/15=6. Now get the ratio of the two pulleys: 28/20=1.4. Multiply the two ratios and you get: 6*1.4=8.4. You can verify by doing the actual rotation counts I described in my post.

jrohland

[shamen222]

I will be doing that tonight, It seems to be a real quick way to tell what your ratio is on an approx. level
I will be able to tell what the ratio is by seeing if it spins 8 and a very little to be 8.1 or 8 and about a half to be 8.4.
thanks for all the Help

[shamen222]

worked like a champ. 8.4