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View Full Version : The ears know


jrohland
01-08-2007, 10:18 AM
I mentioned before my Razor makes a ringing noise which is very noticeable when it is side on (either side). I have decided this sound is the tail belt slapping the inside of the tail boom.

I wondered if mine was the only one doing this. I sought out the Razor videos for the nitro (http://www.helifreak.com/viewtopic.php?t=19221&highlight=razor+nitro) and stretched (http://www.helifreak.com/viewtopic.php?t=23163&highlight=razor+stretched) versions. Now that I know what to listen for, this sound is clearly heard on both videos. If it is the belt, you would expect the stretched version to have it worse. It does, the ringing sound is all over that video.

The sound is similar to a ring the tail blades make at times. However, it is different enough that I can distinctly hear the two sounds.

I have never noticed this on T-Rex 600s. I have heard many of them fly.

I wondered if this is a common problem with larger belt driven systems. As I don't have much time for this research just now, I went right to the Henseleit Three Dee MPe. This is also a 600 sized electric with a belt driven tail. The sound is not heard on any videos of the Henseleit I've found so far.

There are any of several possible reasons the 3DMP does not make this sound:
1) The tail boom is carbon fiber.
2) The tail belt is under greater tension.
3) The tail belt is made of a different material.
4) The design of the tail drive system is superior.
5) The videos don't reveal the sound.

Bottom line, I find the sound annoying. It actually sounds like something is loose and rattling on the heli. I have been unable to find anything loose.

jrohland

DavidH
01-08-2007, 10:27 AM
Bottom line, I find the sound annoying. It actually sounds like something is loose and rattling on the heli. I have been unable to find anything loose.


I will suggest just get use to it. Even the Kyosho Caliber 90 makes the slapping sound in a hover. I have judged at the World Championships for F3C. Even the finest pilots in the world flying a top of the line $3K model with belt drive have belt slap in a hover.

All tail belt drive machines I have been around or owned in my 16 years in the hobby have belt slap at times in a hover.

David

misskimo
01-08-2007, 11:32 AM
3Dmp , I wounder if the bigger tail boom is the reason , and also there ratio is slower. huh? I dont hear that on mine , but I did get a tail kick from a loose belt , my suggestion , tighten the belt