Servo mounting - elementary query?

[erisaman]

I'm installing the stock DS510M servos and note that the manual and the build threads show the use of the brass inserts and rubber grommets - yet some advocate their removal. What's the general opinion for a heli used for sport flying rather than ultimate 3D?

In the same vein, I note on the build vids that the 'silver' screws supplied with the DS510s are put to one side and that a hex headed screw is used to attach the servos. I don't appear to have these hex headed screws, so, do I use the standard/supplied screws instead?

Final query (for the moment) - I have a spare (NIP) 500 TT bearing which I thought I'd install to complement the single bearing and thus eliminate possible vibes. Is it crucial as to how I space these on the TT or just use common sense and place appropriately to ensure even support?

[Deet]

Don't use the sliver screws, they are intended to go into wood.

As to the grommets, I am in the solid mount camp, really it's up to you

IF you decide to use the second TT bearing, evenly spaced is the last thing you want to do.

The single bearing is off centre for a reason, if the two sections of the TT are the same length you get a resonance that will amplify ant vibes. When you add mor ebearings you need to stick to the same principal, keep the gaps between the bearings uneven to avoid a resonance issue.

[erisaman]

Thank you for the prompt response and the confirmation that the silver screws are not to be used. I had recognised them as wood screws but couldn't figure what their role would be - completely overlooking their potential use in 'planks' .

So, am I likely to find a pack with the correct screws (I assume a total of 16?) or do I need to buy them?

Forgive the dumb questions, but are you saying that you would not use the grommets nor the brass inserts?

And thank you for the explanation as to why TT bearings should be installed unevenly - it was a procedure which I had suspected, despite stating the opposite in my query, as I recall doing the same with my 550 build.

[Sharpedge]

There should be a bag with all the hex bolts for the servos. Go ahead and use the grommet and the brass insert. I have both on my efl and have no issues. Just be careful not to screw them in too tight as you will deform the brass insert.

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[Deet]

I don't know that kit but Align will include all the hardware required, and yes, I don't use grommets and bushes on electric helis

You pay a lot of money for an accurate servo that centres well, then soft mount it so the servo can move in relation to the frame, you have just lost the accuracy. I understand vibe issues on nitro helis that may require the soft mounts, but on electrics you don't have anywhere near the vibe levels so why are you using grommets to protect the servos?

Going to put the soap box away now

[magbarn]

Originally Posted by Deet

I don't know that kit but Align will include all the hardware required, and yes, I don't use grommets and bushes on electric helis

You pay a lot of money for an accurate servo that centres well, then soft mount it so the servo can move in relation to the frame, you have just lost the accuracy. I understand vibe issues on nitro helis that may require the soft mounts, but on electrics you don't have anywhere near the vibe levels so why are you using grommets to protect the servos?

Going to put the soap box away now

I dunno if this applies to helis, but on rc cars using the grommets and collars protects the servos from stripping gears during a crash. I would understand this theoretically protect the servos especially in a FBL design where all the force is transmitted directly through the servo.

[Deet]

I've seen metal geared (very expensive) full size servos, with rubber grommets strip all the gears in a crash, so don't see how that logic applies.

What I have been told is you get increased where in the gears caused by vibrations in nitro helis if you don't use the grommets

[erisaman]

Thanks everyone - and if I'd only looked at my current 500 ESP, I'd have seen that the servos are hard mounted there also! Doh!

I'll check out my other hardware boxes but I really don't think I have the servo screws, but there again ..... I now question everything I do .

[erisaman]

Deet! You are entitled to use your soapbox with me anytime, and yep, I put my hands up - the screws were in the kit all along but not in a marked pack. Process of elimination now reveals that the 'blank pack' should have been marked 500HZ13 and contains the servo balls as well.

Apologies for any inconvenience caused ... memo to self, triple check in future!

[Deet]

No inconvenience at all