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Old Jan 25, 2013, 09:04 AM
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United States, SC, Clemson
Joined Dec 2011
113 Posts
I just wanted to chime in and say i experienced this same problem with harmonic vibration. I was using turnigy brushless motors and modified the mounts to accommodate them. What I noticed is that one particular motor had more vibration than another. I was able to trace it to weak mounts. I changed out my mounts with a ply version I rigged up myself.
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Old Jan 25, 2013, 09:34 AM
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mike_o's Avatar
Denmark, kbh
Joined Jan 2012
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Be careful not to blame the mounts too quickly - The vibration has to come from somewhere.

First of all, make sure the props are balanced. If you are still experiencing vibrations, try rotating the prop in relation to the motor by 30 degrees at the time until best setting.

Last resort is using quality props - Graupner 8x5 E-PROPs are very good, and you can even have them in a counter rotating pair.

When you have achieved a reasonably balanced motor/prop combo, then you can look into the mounts; I have secured the front part of the mount with hot glue, which can be removed if need be. Furthermore, I have added a lower foam bridge between the open, lower nacelle halfs. Also hot-glued in place. Runs very, very smoothly now

EDIT: And do NOT fly with the described vibrations!
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Old Jan 25, 2013, 09:43 AM
Bye Bye VP Aug 2010 - Aug 2012
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United Kingdom, London
Joined Jan 2005
6,006 Posts
Quote:
Originally Posted by mike_o View Post
Be careful not to blame the mounts too quickly - The vibration has to come from somewhere.

First of all, make sure the props are balanced. If you are still experiencing vibrations, try rotating the prop in relation to the motor by 30 degrees at the time until best setting.

When you have achieved a reasonably balanced motor/prop combo, then you can look into the mounts; I have secured the front part of the mount with hot glue, which can be removed if need be. Furthermore, I have added a lower foam bridge between the open, lower nacelle halfs. Also hot-glued in place. Runs very, very smoothly now

And do NOT fly with the described vibrations!
Harmonic resonance is something that affects EDF. The advice is to avoid the power settings that bring it on. Also, I think he said he balanced the props.

If he's balanced the props, stiffened the mounts and avoids the affected power settings, then he's done all he can do.
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Old Jan 25, 2013, 12:00 PM
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United States, NV, Las Vegas
Joined Dec 2005
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Quote:
Originally Posted by Gerry__ View Post
Harmonic resonance is something that affects EDF. The advice is to avoid the power settings that bring it on. Also, I think he said he balanced the props. If he's balanced the props, stiffened the mounts and avoids the affected power settings, then he's done all he can do.
I had this problem and it turned out to be that one prop was not tracking right. The two blades were not drawing the samw arc as each other,. I finally fitted two APCs and it went all away. [But still needed more power]

So then I fitted two brushless motors (used the MPI TS II upgrade kit) and the vibration problem came back. This time it was the mounts that needed tightening up. Gorilla glue to the rescue!

And then 3 years later it came back at high rpm. This time it was a bad bearing in one motor. Buzzed a high rpm.

The TS II has some flex in the foam around the wing pod mounts. I think that mine may be getting "foam-fatigue!". If all is tight and balanced it works -- if not fit EDFs :-)

It's always something.....
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Old Jan 26, 2013, 02:10 PM
RTFM
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Antarctica
Joined Oct 2010
1,178 Posts
Took my TS for a maiden today .. everything went well ..
But im a little disapointed about the speed , so im gonna swap for some other motors.
What I got in it now is a pair of 2209 1130kv spinning 8,5x6 counter rotating props.
http://www.hobbyking.com/hobbyking/s...Outrunner.html

I had some 1350kv motors laying around , just finished putting them in ..
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Old Feb 04, 2013, 03:14 PM
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Russia
Joined May 2010
38 Posts
Twin star 2. movie 14 (12 min 53 sec)
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Old Feb 08, 2013, 01:30 PM
Gravity gives sinking feeling
Joined Jun 2011
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Quote:
Originally Posted by Eric Henderson View Post
.....I had this problem and it turned out to be that one prop was not tracking right. The two blades were not drawing the samw arc as each other,. I finally fitted two APCs and it went all away. [But still needed more power] .......

.....
APC Prop is always for me. I had so many problems using el cheapo props - not worth the hassell unless you've patience and time to balance/ track etc. APC have never let me down for the last four years.

Cheers


QUESTION Mike_o's model count so far ???? Bet it's well past double figures now
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Old Feb 08, 2013, 03:06 PM
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Denmark, kbh
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Quote:
Originally Posted by CurrentDude View Post
APC Prop is always for me. I had so many problems using el cheapo props - not worth the hassell unless you've patience and time to balance/ track etc. APC have never let me down for the last four years.

Cheers


QUESTION Mike_o's model count so far ???? Bet it's well past double figures now

I'm 100% with CurrentDude on the APC props; They even provide a wide range of counter rotating pairs, which are great for the TS. I've initially flown it with APC 8x3.8 SFs, have done a quick spin with APC 8x6 thin electric (not the best match for the motors at that time), tried out APC 7x5s for touch and goes in the snow, and currently waiting to try a set of Graupner 8x5 (also counter rotation).

The 8x3.8s are great for their climb performance. So easy to pull yourself out of trouble with these.

Model count, hmmm.. my count back in the autumn said:

Multiplex TwinStar2
AXN FloaterJet
Multiplex PicoCub
Multiplex MiniMag
Scratchbuild foamie 1 (dead)
Scratchbuild 250gr foamie 2
Scratchbuild 350gr Sopwith Camel foamie (flown, but under repair now)
Multiplex EasyStar 2
Multiplex Merlin
Multiplex Easystar 1 (modded during build to an "EasyTwin" FPV platform)
Multiplex FunJet

and since then a few more came into the hangar:

Multiplex EasyStar l FPV (non-aileron)
Mulitplex Sonic Liner
Mulitplex Twin Jet
Mini SkyWalker

During winter time, when my fingers are freezing, the latest ES1 is a pleasure to put together with it's lack of aileron cables. Flies well, still (display in meters):
FPV EasyStar flying high (17 min 16 sec)



The SonicLiner was an offer I couldn't refuse:


So was the classic TwinJet


I'm still considering the full size skywalker for longer lange FPV, but I still haven't found the limit of the ES airframe....

Just a little TS2 touch an go to get back on topic:
TwinStar 2 snow touch'n'go onboard video (0 min 0 sec)
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Old Feb 08, 2013, 04:13 PM
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United Kingdom, Bracknell
Joined Nov 2000
12,040 Posts
Watch the rpms with APC-SF props. They are limited to 65000/diameter in inches. So just over 8100 rpm for 8" diameter ...
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Old Feb 08, 2013, 04:58 PM
Yea, I fly dusty planes..
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United States, LA, Angie
Joined Apr 2009
2,052 Posts
I just put everything in my heads up cart for a Easystar setup for twin Firepower 400 BL motors for $250.00, 3S/3300 50C lipo included. All I need to fly is my RX. That's a hell of a deal for a plane of this quality, I love my Fun Cub. Yea! $254.00 shipped ..Dave/zeezee
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Old Feb 18, 2013, 12:52 PM
Registered User
United Kingdom, England, Clevedon
Joined Jun 2007
131 Posts
Woop woop Sonic Liner

Quote:
Originally Posted by mike_o View Post
I'm 100% with CurrentDude on the APC props; They even provide a wide range of counter rotating pairs, which are great for the TS. I've initially flown it with APC 8x3.8 SFs, have done a quick spin with APC 8x6 thin electric (not the best match for the motors at that time), tried out APC 7x5s for touch and goes in the snow, and currently waiting to try a set of Graupner 8x5 (also counter rotation).

The 8x3.8s are great for their climb performance. So easy to pull yourself out of trouble with these.

Model count, hmmm.. my count back in the autumn said:

Multiplex TwinStar2
AXN FloaterJet
Multiplex PicoCub
Multiplex MiniMag
Scratchbuild foamie 1 (dead)
Scratchbuild 250gr foamie 2
Scratchbuild 350gr Sopwith Camel foamie (flown, but under repair now)
Multiplex EasyStar 2
Multiplex Merlin
Multiplex Easystar 1 (modded during build to an "EasyTwin" FPV platform)
Multiplex FunJet

and since then a few more came into the hangar:

Multiplex EasyStar l FPV (non-aileron)
Mulitplex Sonic Liner
Mulitplex Twin Jet
Mini SkyWalker

During winter time, when my fingers are freezing, the latest ES1 is a pleasure to put together with it's lack of aileron cables. Flies well, still (display in meters):
http://youtu.be/zxRM8knYeOY


The SonicLiner was an offer I couldn't refuse:


So was the classic TwinJet


I'm still considering the full size skywalker for longer lange FPV, but I still haven't found the limit of the ES airframe....

Just a little TS2 touch an go to get back on topic:
http://youtu.be/bN0pkpflthE
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Old Feb 24, 2013, 01:00 PM
Arcee Moron
Justapoke's Avatar
The Netherlands
Joined Jun 2012
925 Posts
Just got myself a Twinstar kit and trying to figger out what aditional hardware I need.


So what motor / ESC to use... I allready have a single NTM Prop Drive Series 28-26A + Plush 25amp laying around and these seem to fit. Good choice to go with these to end up with plenty of power?



Kv (rpm/v) 1200
Weight (g) 57.6
Max Current (A) 18
Power(W) 250

Prop Tests:
7x6E - 11.1v - 90W - 8A
7x6E - 14.8v - 192W - 13A
8x4E - 11.1v - 100W - 9A
8x4E - 14.8v - 222W - 15A
8x6E - 11.1v - 145w - 13A

The stock Permax 400 weighs 73g, so with around 58g for motor and 22g for ESC (if I place this in the wings) I end up with around 7 grams more weight.

To sum it up:

2x NTM 28-26A 1200kv / 250w

2x Plush 25amp ESC

1x HobbyKing HKU5 5V/5A UBEC

For servo's I'll go with the recommanded Hitec hs-81's

Props: I think about 8x6 or Graupner 8x5
Lipo's I have: Nanotech 3S 3300 (could also try 2x Nanotech 3S 2650 but I guess the 3300's are fine)

Tx/Rx: Hitec Aurora 9 / Optima 7 - and I think I will test this OrangeRX 3-Axis Flight Stabilizer that I just got plenty of room for this as well. (first time I will try a gyro)

I'm not yet into FPV yet, but I probable will make some mods to the fuselage so I can get more stuff in the spare room at the back when needed.

Any suggestions what more to think off ? Any reinforcements nessesary with the build besides the usual tape under the fuselage? Wing looks like the spar is very small, did anyone add some carbon there?
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Old Feb 24, 2013, 01:04 PM
Arcee Moron
Justapoke's Avatar
The Netherlands
Joined Jun 2012
925 Posts
By the way I also looked at this, but than again I allready have a single NTM and ESC

Power set Brushless TwinStar II - Natterer Modellbau

They do not mention the prop size.. the included motor mounts look nice, but the NTM's just fit with the standard mount if I reverse them.
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Old Feb 24, 2013, 04:02 PM
Gravity gives sinking feeling
Joined Jun 2011
1,922 Posts
How about a Guardian "Autopilot" ?

Since members here are raving about FPV so I thought I mention it. Two weeks ago I started using it in one of my models - well what can I say "It's the FUTURE" in RC flying.

More I use it, the more I XXXX it.

Mike_o do I correctly remember that you tried it? If you haven't then order one tonight ...

The best GBP I spent on a RC "Gudget".Thinking about installing it in all of my scale and precious models.

Cheers
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Old Mar 02, 2013, 02:33 PM
Registered User
Russian Federation, St Petersburg
Joined Jul 2012
172 Posts
Twinstar II excellent aircraft for the video. It flies very smoothly and predictably.
TwinStar II & GoPro (3 min 41 sec)
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