How does this sound after changes?

[Caj109]

I've just put my specna back together after changing to 13:1 SHS gears and shimming them for the first time(hopefully good enough) and regressed new gears and compression parts.

 

Motor is an SHS high torque.

 

Running on fully charged 7.4 lipo

 

After any advice to see if it sounds good enough or any issues please? First time doing this.

 

Thanks

 

https://imgur.com/a/Pk6hcXx

Edited May 23 by Caj109

[DanBow]

Sounds alright to me.

[Pseudotectonic]

Oh no not another, SHS high torque is not high torque

 

But yours sounds nice

 

But don't be tempted to go 11.1 with this, you will get PME

[Caj109]

41 minutes ago, Pseudotectonic said:

Oh no not another, SHS high torque is not high torque

 

But yours sounds nice

 

But don't be tempted to go 11.1 with this, you will get PME

Good to know it's not high torque, take it will be fine for the gearset still?

 

What's PME? What would cause it? And how to avoid it?

 

only run 7.4v at the moment have no need for more batteries thankfully 

Edited May 23 by Caj109

[Pseudotectonic]

PME means pre-mature engagement, that is when your ROF approaches about 30, your sector gear will be too fast and will try to engage the piston while it is still travelling forward i.e. the sector will slam into the middle of the piston rack and chewing up gear teeth

 

Since SHS "high torque" is actually a 16 TPA high speed, I think with 11.1 and 13:1 gears it will probably go over 30 RPS, hence the PME risks

[Caj109]

21 minutes ago, Pseudotectonic said:

PME means pre-mature engagement, that is when your ROF approaches about 30, your sector gear will be too fast and will try to engage the piston while it is still travelling forward i.e. the sector will slam into the middle of the piston rack and chewing up gear teeth

 

Since SHS "high torque" is actually a 16 TPA high speed, I think with 11.1 and 13:1 gears it will probably go over 30 RPS, hence the PME risks

Oh thanks, always a learning curve!

 

Yeah doubt I'll go that high haha! My site I go to is 25 max anyways and when I tested it earlier was giving me 17 on full auto.

 

Would it be worth getting a better motor or no point? An actual high torque one

[Pseudotectonic]

Nah if it works, it works, but if it happens to get hot during the game, you know why

[Caj109]

4 minutes ago, Pseudotectonic said:

Nah if it works, it works, but if it happens to get hot during the game, you know why

Thanks for that, I'll keep an eye on it. Suppose constant full auto probably won't help.

 

Any suggestions for future you'd suggest?

 

 

[Leo Greer]

I haven't listened to the video yet, as my laptop hates Imgur, but as a note, if that build is running properly, you should be in between 25 and 28 RPS, which is really approaching the PME point. Make sure to check the FPS to see if there's any drop in full auto, or if you have lower RPS than 25! Either one is a sign of PME.

[Caj109]

52 minutes ago, Leo Greer said:

I haven't listened to the video yet, as my laptop hates Imgur, but as a note, if that build is running properly, you should be in between 25 and 28 RPS, which is really approaching the PME point. Make sure to check the FPS to see if there's any drop in full auto, or if you have lower RPS than 25! Either one is a sign of PME.

Even with a 7.4v lipo? Was getting 17 earlier I think on the chrono. Should of checked what I was getting on standard gears to compare.

 

Could be the motor letting me down why low rps? As its only an 16 tpa apprently which doesn't help so would need to look into a higher one which probably would help you think?

 

I'll have a recheck with full auto when I can to see

Edited May 23 by Caj109

[Leo Greer]

Lower TPA means higher RPM (generally). That SHS "High Torque" (not really) has about 35,000 RPM with an 11.1v, or 66% on 7.4v

[ruskitseller]

Sounds fine to me mate, but maybe take it to site and ask for feedback too as sound can...well sound different when recorded.   

Edited May 30 by ruskitseller