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Old Oct 20, 2010, 10:11 AM
bymannan is offline
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Originally Posted by pastorJohn View Post
Noob question: Are the Tower Pro mg90 servos

Best price for an mg90?

TIA
John
4.99 at HK. You can get it for 4.44 if you Swarm it:
Turnigy MG90S Metal Gear

I read that Esky servos are quite delicate, so be careful
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Old Oct 20, 2010, 10:24 AM
jagsta is offline
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Tail servo mounting question


Got my new servo yesterday, and this one comes with some options for mounting, i'm not sure what the best choice is.

It's a tail servo and it's going on a HK450GT, so the tail mounts are metal. The servo comes with rubber grommets and metal collets, but I can't use the collets as the M2 screws required to screw into the mounts don't fit through them.

There are also some plastic spacers which were attached to one of the horns, which you can insert into servo tabs. I don't know which way round these would need to be fitted, they have a collar and i guess that should be towards the bolt head, not the mount?

You can see the plastic spacers attached to the round horn on this photo, it's not my servo but the fittings are the same.



At the moment i've mounted them with the rubber grommets but no collets, and used M2x8 bolts to secure them to the mounts. I've tightened them up so they're pretty solid. I figure this will provide a bit of cushioning to the servo and prevent me overtightening and breaking the mounting tabs.

Is this the best way to go?
Old Oct 20, 2010, 10:33 AM
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Originally Posted by captaingeek View Post
Not sure but it depends on the brands. Align probably publish there numbers. Wood will definitely explode first.
yeah that's correct, different brands= different ratings.

wood and plastic goes about the same mark though right? about 2500-2700 but it can be pushed to 2800 right?

CF depending on make and brand 2800-3300 right? What would happen if i push it to 5000?
Old Oct 20, 2010, 11:12 AM
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i beleive its fairly common to run good align wood blades at 3K without any issues.

don't know about carbon or fiberglass.

i think once you get into the higher rpm ranges if they dont explode then the blad grips, blade roots, or bolts will let loose. needless to say that wouldn't be a good think especially if you are spinng at 5K. you'll almost certainly trash the entire head if not more. I threw a blade once because the spindle bolts weren't locktite and i was luck it didn't cause much damage. but i was just hovering at a low rpm. imanagine a blade coming loose and flying into your face.
Old Oct 20, 2010, 12:02 PM
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Originally Posted by pitchp View Post
yeah that's correct, different brands= different ratings.

wood and plastic goes about the same mark though right? about 2500-2700 but it can be pushed to 2800 right?

CF depending on make and brand 2800-3300 right? What would happen if i push it to 5000?
I think you would just send your gyro mental at that head speed and you gotta think how fast that tail will be spinning and generating vibes also,,,dont do it unless you want to throw a good heli in the bin
Old Oct 20, 2010, 02:43 PM
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Try to avoid the rubber grommets on the tail servo. You need as less play as you can get. the grommets are a good idea on a shaky nitro model heli to prevent servo damage.
I made myself a square washer for servo mounting by drilling a 2mm hole in a thin metal plate and cut my washer out.


---

i dont know about 5000rpm HS, but this is what 4000 can do, seems plenty for the average 3d flier....


Kyle Dahl with a 4000 headspeed 450 (2 min 32 sec)
Old Oct 20, 2010, 04:00 PM
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Yeah thanks sp00fman, think thats what i'll do. Anyone know how to use the spacers?? (collar to the bolt or the mount?)

That 4000 HS 450 is insanely quick!
Old Oct 20, 2010, 04:26 PM
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I think most CF/GF can handle at least 3100 since Ive been running that on various HK blades with not trouble. I think these will hold better than the grips. I had grips from HK that went poof in a crash, just separated in half. Unless youre over 3500 HS I wouldn't worry about the blades holding up.
Old Oct 20, 2010, 04:58 PM
Magic k2 is offline
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Originally Posted by sp00fman View Post
Try to avoid the rubber grommets on the tail servo. You need as less play as you can get. the grommets are a good idea on a shaky nitro model heli to prevent servo damage.
I made myself a square washer for servo mounting by drilling a 2mm hole in a thin metal plate and cut my washer out.


---

i dont know about 5000rpm HS, but this is what 4000 can do, seems plenty for the average 3d flier....


http://www.youtube.com/watch?v=plEOJlw10cU
This guy looks plenty good with the heli ,,,BUT,,The video has been speeded up to make it look 2 times better than it is,,,starts off ok but then speeds up,,,watch how fast the cammera changes direction,,,not possible for the cammera guys head or hands to move direction that fast.
Old Oct 20, 2010, 05:13 PM
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Originally Posted by Magic k2 View Post
This guy looks plenty good with the heli ,,,BUT,,The video has been speeded up to make it look 2 times better than it is,,,starts off ok but then speeds up,,,watch how fast the cammera changes direction,,,not possible for the cammera guys head or hands to move direction that fast.
I agree I think it has been sped up to
Old Oct 20, 2010, 05:25 PM
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Originally Posted by Magic k2 View Post
This guy looks plenty good with the heli ,,,BUT,,The video has been speeded up to make it look 2 times better than it is,,,starts off ok but then speeds up,,,watch how fast the cammera changes direction,,,not possible for the cammera guys head or hands to move direction that fast.
that's what I was going to say.

3200 is the max HS i can do on my hk450 plastic version. There's vibrations, but it a different vibration, the gyro doesn't pick it up, and these vibrations, tend to make some screws losen up, so I always do a pre and post checks 15 mins for all screws, and I CA them or Threadlock them.

Magic, I'll be doing this on a 250. my hk250 plastic is holding up 4500-4400. I have a tarot 250 built for 5000+ HS.I have a no name CF blades and I'm not sure if they can with stand the power of 5100 - 5000 HS. Hence I asked about blade ratings.

This is the Tarot 250
Last edited by pitchp; Oct 20, 2010 at 05:56 PM.
Old Oct 20, 2010, 05:48 PM
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it's not sped up. He has a followup video where he proves it with an audio recording and a stopwatch or something.

Kyle proves his 4000 hs 450 isn't fake (3 min 41 sec)


and someone will say the music was edited and the stopwatch wasnt in view the entire time.. faking the video would take more work than just doing it.
Last edited by rocketscience; Oct 20, 2010 at 05:56 PM.
Old Oct 20, 2010, 06:23 PM
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it's not sped up. He has a followup video where he proves it with an audio recording and a stopwatch or something.

http://www.youtube.com/watch?v=d-y6f...eature=related

and someone will say the music was edited and the stopwatch wasnt in view the entire time.. faking the video would take more work than just doing it.
RS: you're a man of logic and reason... Check out the first video that was posted here. Pay attention to how he landed the heli. My 4g3 is slower than that, and running at a higher HS. I have to show you a video of Bert K with his 450 pro TT 3500-3400 and see the difference. I just got to find the video. So adding 500 more doesn't make it that fast.
Last edited by pitchp; Oct 20, 2010 at 06:33 PM.
Old Oct 20, 2010, 06:43 PM
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The chopper he's flying is a FBL and will roll and flip much faster than a chopper with a flybar. The videos I found that were of Bert Kammerer all had him flying stock Align choppers (I haven't seen one yet with him FBL).

The videos aren't fake, he's just that good and his helicopter is just tuned that well. End of story.
Old Oct 20, 2010, 06:48 PM
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Originally Posted by Barak1001 View Post
The chopper he's flying is a FBL and will roll and flip much faster than a chopper with a flybar. The videos I found that were of Bert Kammerer all had him flying stock Align choppers (I haven't seen one yet with him FBL).

The videos aren't fake, he's just that good and his helicopter is just tuned that well. End of story.
Lets assume that it isn't fake. I have to give to the camera person for keeping up that well on the heli, and not even losing it once. And you know how hard it is to video capture a fast moving heli.

I'd believe it, if he said he was running that @ 5K HS but not 4K Flybarred or Flybarless, no way it goes that quick at 4k. 5k yes, but not 4k
Last edited by pitchp; Oct 20, 2010 at 06:57 PM.


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