Purposely cutting servo arms to fail in a crash??

[RcRotaryMadness]

Just a thought... replacement servo gears (esp for these torq servos) are expensive and a pain to do (imo).

So i was thinking.. try to make it so the servo arm will fail before the gears do... i know theres already alloy arms you can buy that are designed to slip but whatabout using plastic servo arms and put a cut into them to weaken them a little.. almost to give it a fracture line to break on in a crash?

Just an idea... obviously its a balancing act between cutting them enough to break in a crash but not so much to break in normal use?

[st200ol]

It could work, the problem I see is that putting a cut in the arm may create/start a stress crack which may get worse until one day the inevitable happens...

[xygax]

Just a simple explanation. If you put a weak plastic part in the way between the head and the servo think about what happens when you execute a tic-toc. You extend the cyclic probably to full pitch positive with cyclic and then just as the heli has got moving you reverse that and extend full pitch and cyclic negative. This is equivalent to a minimum of 2G on the model and probably closer to 4G if you thing a floppy plastic thingy will take that without flexing let alone breaking then go buy a Shuttle that had the whole mecanisam made from floppy plastic.. !!! push up and wait.... probably not the best idea. There are uasally a sacrificial gear in the servos but Its never sold alone only as a set that I don't understand...

[SGD]

Bad idea. Servo arms work better the stiffer they as less flex means more accurate movement transfer. The loading can be quite high on the arms as can be seen from some of the torque outputs from some servos at 25Kg + Apart from inducing a flex point any material removal could produce a starting point for a stress fracture and with the continual servo movement the arm would soon fail.

[scuba steve]

maybe use servos with cheaper gears ?

and from my experience of many crashes over the years...you just never know what gong to break, it all just seems totally random

[tonystevens]

Don't do it lol! Just put plastic arms on it, put some glitter on them if your worried about how crap they look

[dogbiscuit]

plastic arms seem to break most of the time anyway in a crash before the gears, without a cut in them...... i am just off to find the pritstick and glitter....

[moyesboy]

My BLS451 have the star shaped plastic wheels on them push pull. Response to controls is no different to what it was when I had beefier arms on there. I have broken several in crashes.
I can't see how there can be significant distortion in the servo arms with push pull links. But I've never done any gears in my BLS451 in years of flying. They are on direct power from the 2S lipo as well.

[RcRotaryMadness]

Lmao gliter.. might do that just to impress Gaz lol
The heli in question is a 550 so lower forces than a 700 i'd expect.. but yes plastic arms as they are should break before the gears? They got allow arms on atm.

[JoeBailey]

Purposely cutting servo arms to fail in a crash??

I only use plastic arms on mine (except the g4 cause its got special ones )
Never had one break in flight but broke a few in crashes.

[KevDavies]

I use Futaba HD plastic ones, will hold plenty torque, but if stressed it will rip the splines out. Personally im not that bothered if I kill servo gears, theyre sacrificial in my eyes. You could see if they do a sacrificial plastic 1st gear Matt if your that concerned, then only that 1 gear will go.

[aro03]

The synergy e7 uses a combination of a carbon plate and a plastic wheel to provide stiffness in flight whilst also being sacrificial in a crash. Align, futaba and spektrum plastic wheels fit the carbon arms with no modifications. The carbon arms might be suitable for your head geometry; if you need measurements let me know.

P1010872 (722x1280).jpg

[tonystevens]

I only use plastic arms on mine (except the g4 cause its got special ones )
Never had one break in flight but broke a few in crashes.

They are special, but I still whipped mine off the raptor in favour of plastic!

[JoeBailey]

Purposely cutting servo arms to fail in a crash??

They are special, but I still whipped mine off the raptor in favour of plastic!

Most of the control levers on the G4 seem to be made from some kind of silver plastic, think its cheeseium but not sure :S