HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Sep 05, 2012, 01:58 PM
Registered User
United States, MN
Joined Feb 2011
4,374 Posts
Quote:
Originally Posted by Atomic Skull View Post
Tarot integrated belt drive tail (the 2 piece one that goes together with 2 screws) produces much less vibes than the Align style belt tail. No idea why this is it's just there. A nice side effect is that you don't need to flip the grips anymore either because they changed the geometry of the arm that holds the bell crank to give equal pitch in both directions.
I had a HK tail not a Tarot. And it was time for it to go anyways as the vertical stabilizer mount was built into it and thus there was no pin to prevent rotation of the tail on the boom and occasionally it would twist when changing head speed.
grimbeaver is offline Find More Posts by grimbeaver
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 05, 2012, 03:48 PM
Registered User
Atomic Skull's Avatar
Joined Dec 2011
3,260 Posts
Quote:
Originally Posted by grimbeaver View Post
I had a HK tail not a Tarot. And it was time for it to go anyways as the vertical stabilizer mount was built into it and thus there was no pin to prevent rotation of the tail on the boom and occasionally it would twist when changing head speed.
I never found the pin in Pro/Sport tails to be all that useful as it still allows the tail to twist somewhat and you still have to tighten the screws to ridiculous amounts of torque to secure it. I always glue a 3mm wide strip of paper longitudinally to the boom where the tailcase slides over and it completely secures the tail and prevents twisting without needing to over tighten the screws.

The same idea works to keep the tailboom secure in the boom holder, I cut a strip of typing paper long enough to wrap around the boom (wrap twice for plastic holders, once for metal) and glue it on (I find that wood glue works better than CA for this but for the tailcase end you need something like CA or no mix epoxy to hold the strip on)
Atomic Skull is offline Find More Posts by Atomic Skull
Last edited by Atomic Skull; Sep 05, 2012 at 04:00 PM.
Reply With Quote
Old Sep 06, 2012, 03:33 PM
Professional heli wrecker
Luvmyhelis's Avatar
United States, WA, Spokane
Joined Oct 2010
4,260 Posts
Better yet guys, drill a 2mm hole in the actual tail hub where the boom inserts into it and pin the boom inside the tail hub. Been doing this for years.

And, oh yeah grimbeaver. This is a B400 cnc heli cf modified frame. Best frame I have ever found on any 450 since it sports a 3 bearing main support!
Yeah, I agree, the plastics suck though. Plus I would rather have my teeth drilled without novacain before owning a walkera!

I just ran the Tarot one piece hub in a brand new setup that I just now test flew after building for a friend of mine. I really like the one piece hub even far more than the align version, especially the fact you can pull the shaft assembly out with two bolts. I however still have some hate for the single sided ball slider, and the slop they induce. However this heli flew with the lowest vibes of any heli I have ever built. Sadly the stock Tarot hub factory bearings were unuseable as they were grainy right off the bat. I also use tempered align tail shafts as the tarots are undersized and tend to wag in the bearing cradle. But so do the stock align shafts, plus the actual gear hub exploded and separated on the last align shaft I used.

Quite a few vibes from 450s eminate from the tail in most the charts I see and has been a huge problem for most guys.

I eliminated the stock Tarot grips using a heavily modified G5 grip assembly with ceramics that I precision balanced. These grips are truly the only slop free no wag grips I have ever been able to find. What makes them gold is that they spread out the bearings farther into the grips, and also use a fatter thicker bearing at the base to support the grips. With ceramics and some work these things rock!

There was a bad rep that was circulated about the G5 tail that it was not able to handle the higher rpm levels. Total crap. They were made by the same company that produced the Sonix tails and both were prone to bolt failure in the grips. Once you addressed this and the bearings the system is bulletproof. These also have 170,000lb tensile strength grip bolts. I have repeatedly ran this system up to insane speeds with headspeeds at 3600 and an overdriven tail. Never had a failure yet in hundreds of flights.

Then I changed out the slider assembly to an align. Only because the slider bearings were better and the brass slider rotated true. The tarot wobbled and the bearings were junk right off the get go. I also eliminated the new supposedly better fat bearing upgraded tail grip linkage as it threw the grips off center at speed.

Rick, we have been looking for the ultimate vibe layering to reduce vibes getting into the gyro and I think I finally nailed it. Most good vibe layering also tends to allow the Sk720 to wag or overshoot on its stops. This didn't. And even though the heli is equipped throughout with abec 5 rated ceramics I refuse to believe this is the cause of the lowest flight vibes I have ever seen. Even with 15/20mph winds buffeting the heli to the point it contacted the ground a few times the logs remained insanely low.

The vibe layers go something like this.

Sk720
3m black double sided sticky gyro tape
Sk720 metal vibe plate
Two different thin layers of 3m gyro tape
Another Sk720 metal vibe plate
Two 3/4 strips of align pu gel
and another thin layer of 3m tape so the pu gel adheres
One velcro strap loosely tied over the gyro for insurance.


Here are a few pics to show the mounting and heli for reference. Usually I inside mount all my Sk720s. But this time I did it outside so the guy I am sending this to will have easy access to it. All the parts on the heli are pretty straightforward. The shell is a double panel reinforced CNCheli B400 frame. The forward servo has been moved up into the head area and a custom Tarot battery tray was installed to run the larger 2250 6s Nano battery. The motor is a Hyperion 6s 1630 with ceramics and a Rhino 9t pinion. 144t Microheli delrin gears, modified 550 skid assembly for flying on grass. MsComposite 420mm blades. Rave450 grips modified to fbl using 500 pins. HK head and Kbdd orange damps. Helihaven 63mm custom fs with 170000lb 3mm set bolts. Mikado swash lock, dual bearing swash with raised center. Trex 600 grip to swash links and link ends. Hs65hb cyclics and an MksDs95i on the tail. Extended .020 wall thickness 12mm boom with Trex 500 belt. G5 11t tail drive upper gear to 10t tail. G5 grip mod, Kbdd 61mm blades. Custom dual boom support system. Tarot cf rear stab and pro cf boom wing. And a dual tube reinforced 5mm rear servo to tail control rod using Quick UK delrin ends. The esc is a heavily modified Ice50 running a Castle 10a bec.

All of the build is pretty straightforward and the parts were blueprinted, balanced, and indexed. Again, my only real beef is the single ball slider mech. You just cannot get rid of all the slop with these.

The low vibes are insane with the vibe layering. And I will def swear it has more to do with that than the mechanical work on this heli. I have put out a lot of them and never seen vibe logs like this before.
Luvmyhelis is offline Find More Posts by Luvmyhelis
Reply With Quote
Old Sep 06, 2012, 04:17 PM
Registered User
Atomic Skull's Avatar
Joined Dec 2011
3,260 Posts
Quote:
Originally Posted by Luvmyhelis View Post
just ran the Tarot one piece hub in a brand new setup that I just now test flew after building for a friend of mine. I really like the one piece hub even far more than the align version, especially the fact you can pull the shaft assembly out with two bolts. I however still have some hate for the single sided ball slider, and the slop they induce. However this heli flew with the lowest vibes of any heli I have ever built.
Yes the 2 piece tailcase has much lower vibes than the Align stile tailcase. I use that and the one piece mainshaft bearing block in my 450.

Quote:
Originally Posted by Luvmyhelis View Post
And, oh yeah grimbeaver. This is a B400 cnc heli cf modified frame. Best frame I have ever found on any 450 since it sports a 3 bearing main support!
The Gsun 450C has three mainshaft bearings too and a bunch of other interesting differences like a motor that mounts from the top and open air servo mounts. There's a build review on it on helifreak.

http://www.helifreak.com/showthread.php?t=293470

I would replace the head though because it uses a 3mm feathering shaft and no thrust bearings. (could use the $9 HK FBL head or the $15 RJX clone to keep it cheap)
Atomic Skull is offline Find More Posts by Atomic Skull
Last edited by Atomic Skull; Sep 06, 2012 at 04:26 PM.
Reply With Quote
Old Sep 06, 2012, 06:33 PM
Aviation Technician
GetToDaChopper's Avatar
Joined Feb 2012
315 Posts
Quote:
Best frame I have ever found on any 450 since it sports a 3 bearing main support!
Quote:
The Gsun 450C has three mainshaft bearings too
The Mini Protos does as well with a 6mm hollow main shaft to boot !
GetToDaChopper is offline Find More Posts by GetToDaChopper
Reply With Quote
Old Sep 06, 2012, 06:39 PM
Aviation Technician
GetToDaChopper's Avatar
Joined Feb 2012
315 Posts


wow that's quite a stack under that 720 ! it doesn't move around too much ?
GetToDaChopper is offline Find More Posts by GetToDaChopper
Reply With Quote
Old Sep 07, 2012, 02:31 PM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Quote:
Originally Posted by GetToDaChopper View Post

wow that's quite a stack under that 720 ! it doesn't move around too much ?
I'm doing the same mount - I can't crack/roll the heli enough or hard enough so that it matters.

Rick
Rickn816 is offline Find More Posts by Rickn816
Reply With Quote
Old Sep 07, 2012, 04:01 PM
Professional heli wrecker
Luvmyhelis's Avatar
United States, WA, Spokane
Joined Oct 2010
4,260 Posts
Quote:
Originally Posted by Rickn816 View Post
I'm doing the same mount - I can't crack/roll the heli enough or hard enough so that it matters.

Rick
Honestly I haven't been able to get the unit to shift, unlike when I was running zeal. Usually at the end of a violent manouver you will see a slight overshoot or wag if the unit moves and settles back to neutral. This is rock solid. Looks kinda like it would twist easily but it doesn't.

A.S. saw that body and almost picked one up! If I am not mistaken Nightflyer did a build thread on one of these almost a year and a half ago over at HF. I like the design but would beef up a few CF areas is about all. My head runs a 4mm fs. The B400 head version was crap in any config. Plus now I am moving towards the 16mm boom in all my stretched 450 builds. This way I have more rigid booms and much much more room for the belts without contacting the boom anywhere in the twist area. Also I am now moving away from gear to gear contact as I have gotten way too much power to run them safely. The contact patch in the 450 gear isn't able to keep up with the power levels of the 6s and now 12s power train. I can and am blowing through delrin gears during stressful pitch changes. Totalled my last heli two weeks ago due to gear strippage. Time for a custom belt drive.

But again we come back to a very well controlled 3 bearing mainshaft support. That is the heart of the heli and effects everything it is in contact with. and I do like the servo layout on that also, equal lateral servo arm movement. I would love to see some logs out of that if possible?
Luvmyhelis is offline Find More Posts by Luvmyhelis
Last edited by Luvmyhelis; Sep 07, 2012 at 04:14 PM.
Reply With Quote
Old Sep 07, 2012, 09:55 PM
Aviation Technician
GetToDaChopper's Avatar
Joined Feb 2012
315 Posts
Quote:
unlike when I was running zeal
is that the Align PU gel your using now ?
GetToDaChopper is offline Find More Posts by GetToDaChopper
Reply With Quote
Old Sep 07, 2012, 11:39 PM
Registered User
Atomic Skull's Avatar
Joined Dec 2011
3,260 Posts
You got me thinking about basing a 450 build on a $12 plastic B450 frame with midgrade electronics and an HK RJX clone head. Would make for an inexpensive but decent quality machine, and very light. How did you adapt the 12mm boom to the B400 frame? Did you use the eflight maingear and tail drive gears?

Have you ever tried using oversized cyclics in a 450 for more cyclic authority? Right now I'm using HG-D260's in my 450 sport.
Atomic Skull is offline Find More Posts by Atomic Skull
Last edited by Atomic Skull; Sep 07, 2012 at 11:50 PM.
Reply With Quote
Old Sep 08, 2012, 02:31 AM
Professional heli wrecker
Luvmyhelis's Avatar
United States, WA, Spokane
Joined Oct 2010
4,260 Posts
I use MksDs95s in all my 450s. There really isn't any more room in the stacked servos behind the head for anything bigger. The HK Rjx knockoff for $15 is amazing for the $$. Stuff some Kbdd reds into them and they are better than the Rjx. The fix for them is to run longer swash loc bolts and lock nut the backside. Out of half a dozen of them I only had one that was poorly machined. And the aluminum is a harder grade than the Rjx was. Plus the $6 360mm composite blades at HK are brilliant! I ran these for years at 3600rpm and never lost one.
I used to use the step up eflite tail drive aluminum gear as it worked also with the trex belts due to the thin gear ridging. But lately I have had two of them fall apart. So I use G5 tail drive uppers on them now for the guys I build them for. Also I used the HK Cf 12mm tube as my boom and stretched it. Solid, and cheap. Forget the belt slot as it weakens it. You can test the tension at the tail. I do carve a slot where the guide is. Easy mod even with a dremel. Or when running fatter belts I go with .020 thick aluminum booms. Then heavily modded align spec tails with G5 grips. The last one I built I double panelled it and ran 4mm thick bearings. Tight tight shaft.. That is the weak spot as the align tail design purely sucks. The absolute best tail out there was the metal G5. But they are impossible to find. And here is a killer mod for the cheapo frame. Drill it out to 11/16 which is almost dead on and run a 16mm boom. Killer. Then a $10 HK 500 tail hub with oversize bearings down to 3mm, space the tail gear on a longer shaft and there is virtually not a spec of tail shaft wag. The bellcrank still works with some easy mods. Cool tail. Or even a 14mm and use the titan 325 tail which is decent. I always use MH delrin gears in all my 450s. Not a single trex nor eflite gear I have ever had rotated concentrically or straight. Try out the Yep clone (YGE) 45 esc for $23. I was stunned at how well they are built and run. Great bec also. And they work with the Sk gov. On mine I just add in one of the thicker heat sinks from the $5 HK kits and they barely run warm.

If you want cheap cyclics that still run well the last one I did for a guy used the old venerable HS65hb gears. I find them new 3 for $50 here at RcGroups or HF shipped and they still work fairly well. Even then you have some carving to do. Plus with a new company pushing sets of 10 ceramic bearings for $5 on ebay it is relatively cheap to outfit the entire heli with them, except for the flanged ones.
Luvmyhelis is offline Find More Posts by Luvmyhelis
Last edited by Luvmyhelis; Sep 08, 2012 at 02:43 AM.
Reply With Quote
Old Sep 08, 2012, 03:15 AM
Registered User
Atomic Skull's Avatar
Joined Dec 2011
3,260 Posts
Quote:
Originally Posted by Luvmyhelis View Post
I use MksDs95s in all my 450s. There really isn't any more room in the stacked servos behind the head for anything bigger.
You can get modified upper frame panels with 30.2x13.5mm servo holes for the 450 Sport. They'll also fit in the SEv2 if you drill an extra screw hole or just use the Sport unified boom holder/tail gear assembly.

Quote:
The HK Rjx knockoff for $15 is amazing for the $$. Stuff some Kbdd reds into them and they are better than the Rjx. The fix for them is to run longer swash loc bolts and lock nut the backside. Out of half a dozen of them I only had one that was poorly machined. And the aluminum is a harder grade than the Rjx was.
Put a 2x3.6x0.2 steel washer in between the flange bearings and you can tighten the screws as much as you like without binding. The steel ones like HK uses work best, the copper ones from the Tarot washer bag work ok but you get a bit of drag on the arms while with the steel ones the arms are totally free. Regardless I still prefer to use an 18mm screw with a nut on the other side. The screws provided are shorter than in the actual RJX head. (14mm in the clone vs 16mm in the real RJX head.

HK needs to start selling those washers in bags of 100, right now the only way to get them is to hoard any extras you have.

I use trueblood super hard greens for dampers.
Atomic Skull is offline Find More Posts by Atomic Skull
Last edited by Atomic Skull; Sep 08, 2012 at 03:21 AM.
Reply With Quote
Old Sep 08, 2012, 02:31 PM
Professional heli wrecker
Luvmyhelis's Avatar
United States, WA, Spokane
Joined Oct 2010
4,260 Posts
Quote:
Originally Posted by Atomic Skull View Post
I use trueblood super hard greens for dampers.
I just got a bag of those in to try on my DFC setup. They look interesting to say the least since they are so hard.
Luvmyhelis is offline Find More Posts by Luvmyhelis
Reply With Quote
Old Sep 09, 2012, 03:32 AM
Registered User
Denver, CO
Joined Dec 2005
6,317 Posts
Quote:
Originally Posted by Luvmyhelis View Post
---Also I am now moving away from gear to gear contact as I have gotten way too much power to run them safely. The contact patch in the 450 gear isn't able to keep up with the power levels of the 6s and now 12s power train.---
My Bergen has double stacked gears, for its 8 horsepower twin.
Roto Rob is offline Find More Posts by Roto Rob
Reply With Quote
Old Sep 09, 2012, 12:26 PM
Professional heli wrecker
Luvmyhelis's Avatar
United States, WA, Spokane
Joined Oct 2010
4,260 Posts
Quote:
Originally Posted by Roto Rob View Post
My Bergen has double stacked gears, for its 8 horsepower twin.

Drooool...................
Luvmyhelis is offline Find More Posts by Luvmyhelis
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale CSM SL 720 gyro $150 Shipped Giovanni Day Aircraft - Electric - Helis (FS/W) 1 Jul 02, 2011 07:18 PM
Discussion Skookum 720 Rickn816 Electric Plane Talk 2 Feb 07, 2010 09:01 AM
Sold NIB Extremeflight Torque 2812/720 RichR Aircraft - Electric - Power Systems (FS/W) 2 Jan 15, 2010 09:36 AM
Sold NIB Torque 2812/720 RichR Aircraft - Electric - Power Systems (FS/W) 0 Jan 13, 2010 12:00 PM
Sold Torque 2812/720 Brushless motor RichR Aircraft - Electric - Power Systems (FS/W) 2 Aug 27, 2009 09:19 PM