General How tight is tight?

[treff]

Well, back from hols and into the build of HK450gt pro2. I'm on the second set of cyclic servos and it's driving me nuts. I fit them, just pinch the bolts up and let the thread loc do its job and every time the lugs just break off. They are the cheaper brands EMax and Tower pro but I was expecting something a little more substantial or am I missing something. Again, I am only just pinching the bolts up but
the plastic just seems to crumble. It there any gauge I could apply i.e. more than finger tight, less than finger tight, just a slight tweak to get them to sit right. I ask because I have now ditched the idea of the cheap end bits and pieces and sent for some Savox but........................................................................
am I fitting them wrongly. I would appreciate any info, ideas that all you knowledgeable guys might have. Cheers

 

[Slobberdog]

Its just the way the plastic is Treff, I had the cheap Ripmax servos in mine that I just got rid of and tightened them quite snug and no issues, just built the new Align bird last weekend and the same thing, bolts quite snug and no issues,

you might want to ensure you have a washer to distibute the load a bit, post up a pic of how you got them in so we can advise further

Hope you had a good holiday by the way.

 

[breeze400]

Are you using the rubber and brass mounting kit on them? If not they will brake! The little brass bushing is what stops you from over tightening them!

 

[treff]

Many thanks for the replies. With the cheaper servo you do not get brass bushing or the rubber grommets. I do not think there is room to fit grommets because of the size on a 450 helicopter. Yes I do fit washers to spread the load but it seems to make no difference. I even fitted a little of the double sided tape to take some of the strain. I only pinch them just past the finger tightness and to get them to fit flush and the lugs crack and break off. I have checked the metal mounting to see if there is any obstruction and they appear to be a reasonable fit with no high spots. I must be missing something here although there are plenty of info on breaking lugs on the cheaper servos. Maybe I have been unlucky. It would not be the first time LOL. Cheers.

 

[coolgabsi]

on that small size bird Sam you wont have brass bushings like the standard servos do


as far as the servo holders breaking.. Plastic does not like loctite. And some servo casings LITERALLY WITHER as soon as any loctite touch them. Like tower pro mg90 servos. I had that experience. More than likely the loctite is oozing out of the hole when you screw the screw in, and destroying the plastic or making it weak.

I recommend cleanign the surfaces well and using VERY VERY small amount of loctite. like Teeny tiny bit.. use a washer to it has a larger area to hold and preventing cracking of a smaller surface and just snug.. no force.. just snug, so the servo cant be moved and like you said, let the loctite do its job then

 

[breeze400]

I just bought two cheep micro servos and they came with mounting kits! $13.00 a piece. I think they were hs81's.

 

[treff]

Thanks coolgabsi for the info. Yes I do tend to over do the thread loc. I am running out of cupboard space to hide all these cheap servos from the wife LOL. The only answer I can see is to go up market, which I have now done. ~No more cheapjack rubbish. If its expensive I will buy it, in fact if the price is not extortionate I will not even give it a second glance. Bring it on, bring on those cast iron servo cases, bring on the hand made, hand carved servo arms fettled from pure cryptonite aluminium. I think I'm havein one of me dizzy spells LOL Cheers

 

[Tony]

Those dark colored cheap servos like the T-Pro and such use VERY brittle. This is a case of you get what you pay for. I have broke many of those tabs and only use them on foamie planes where I glue them in. Then I break the tabs off anyway. Best thing you can do is get something like the EXI D213F or the like in your area if you are wanting to use cheap servos. It goes without saying that we highly suggest the DS415s and DS425's for the 450's.

 

[treff]

Cheers Tony. Yes very nice servos all the cheapos I have, which is almost a cupboard full will go in a smallish glider or gliders. I think I have enough now to begin selling them back to China LOL. Its about time they had some of their crap back.

 

[treff]

Savox servos arrived and my goodness what a difference. You do definitely get what you pay for. Solid, well engineered and a delight to fit. WELL CHUFFED.

 

[Slobberdog]

Nice Treff, how much else you got left on that bird.

 

[treff]

Not a lot really. I have to fit the main blades, do a little bit of checking with the pitch gauge then its good to go. This heli is going to be really good< I can feel it. Just have to get the Bl--dy weather. I can't believe it's so cold for this time of year. I could have brought an Align Pro or the Blade 400 with the bits and pieces I have added to this bird. Savox servos, Align tail servo, Align main gear, not to mention my DX8 having a new board fitted. One of the ics had died, probably the cause of the first heli hitting the ground. I have started to rebuild that one as well so will have two on the go. I am also thinking of the 130X which I think will be very good and better than a simulator. Just after 12.30 here and outside the foxes are making awful racket, just like babies crying. Cheers Slobberdog, thanks for the reply.

 

[corsair_pilot]

Treff, I feel your pain!!
I've done the same thing with mine, and is very much becoming less of a clone and more of an Align bird.
Have learnt my lesson, there is a time and place for the cheap stuff, but the entire bird shouldn't be done on the cheap.
My parts arrive the LHS tomorrow, so hopefully over the few days I'll have off, I can get mine up into a hover.

Foxes making a ruckus, I dont have foxes, but have 3 huskies, and their howl when the three of them sing must sound similar. I'm surprised we haven't had people looking into our yard when they go off, sounds horrid like someone strangling an animal. At least they don't carry on for too long

 

[treff]

Yes corsair_pilot your right about becoming less of a clone. I have been building and flying gliders for 40 years and I can say that helicopters are a total different kettle of fish. Some things you just can not skimp on with helicopters, there to much that needs good engineering. Where you could get away with cheapo servos on a smallish glider helicopters need more thinking about but great fun never the less. I am really looking forward to getting this into the air but mostly bringing it back to earth like a feather LOL. I'm also at the almost hovering stage more of the crashing stage LOL. Cheers