Problems with t-rex 450 sport

Khiledim · 02-24-2010, 03:19 PM

Hi,
I have some weird vibrations problem with my sport.
It only vibrates in normal flying mode during hovers.
It started to vibrate after some time out of the box - had no crash before!
I tryied to locate the problem by changing different parts,so I chaged shafts,
blades,dampeners, lower&uper mixers,blade grips,grip's bearings,
main gear & one way. I also played with thrittle curves and no succes,
so i think it can't depend of rpm's...

Here's the short video with it.

YouTube

d_adam · 02-24-2010, 03:36 PM

not depend of head speed but it happens during hover in normal flight? nonsense
You said that when you increased throttle curve, it still vibrate ? ... when you increase enough the curve will be the same as idleup so non sense x2

increase your throttle curve....

Wolfpackin · 02-24-2010, 03:45 PM

Look at that...two guys from Poland.

+1 on possibly low headspeed.

What are your throttle & pitch curves and what size pinion?

Did you check or replace the main and feathering shafts?
Those can bend on just a hard landing.

d_adam · 02-24-2010, 03:47 PM

he did mainshaft from plasticine

Khiledim · 02-24-2010, 03:49 PM

Quote:

Originally Posted by d_adam

he did mainshaft from plasticine

Yes, sure i took it from your t-rex 700.
Don't make offtopic in my thread anymore please.

Quote:

Originally Posted by Wolfpackin

Look at that...two guys from Poland.

+1 on possibly low headspeed.

What are your throttle & pitch curves and what size pinion?

Did you check or replace the main and feathering shafts?
Those can bend on just a hard landing.

As i wrote beafore of course i have tryed to change both shafts. Same results.
New align engine with pinion 14, thro curve 0-55-90 right now in normal - tryed higher also.Same results.

life2short1971 · 02-24-2010, 03:53 PM

d_adam · 02-24-2010, 03:55 PM

No worry, I will buy new one for YOU !!

OK Stop my friend

I think, you are very nervous

Who can help him ?

Is here a psychiatrist ?

Joke
OK, ok ....
I forget that It isn't polish forum

jaywhy · 02-24-2010, 03:59 PM

That type of vibration is referred to as `porpoising` (like the animal) - and it's from either too low of a head-speed or something too tight like the blade grips. Maybe something in the tail drive too, but I'm not positive about that.

eDeK · 02-24-2010, 03:59 PM

d_adam,Why you are saying it now,in his thread rather to help him in real.

Stop trolling.

Aussie_phoenix · 02-24-2010, 04:48 PM

Quote:

Originally Posted by Khiledim

New align engine with pinion 14, thro curve 0-55-90 right now in normal - tryed higher also.Same results.

Try changing the normal throttle curve to 0-80-100 and normal pitch curve to 40-50-100 then see how it goes.

.

zen · 02-24-2010, 04:50 PM

Khiledim—

the heli in the video shows the typical movement when there is not enough head speed. Instead of 55% at mid-stick go to 80% or more. No less than 70. If you dial it up to that range the up-and-down motion of the tail ought to stop.

The other factor is the size of the pinion gear on the motor. 11 tooth for hovering and basic maneuvers, 12 tooth for more aggressive upright flight plus loops, rolls, and flips.

To give you some idea I fly a 450 SE (V1) with a 12 tooth pinion on an Align 430 L motor. The throttle curve at center stick in both normal and idle up is 85%. At zero pitch (center stick) the head speed is 3,000 RPM, dropping to 2,800 or a little less when it lifts off.

Regards,

Glen

yakflyer · 03-01-2010, 08:07 AM

some good info here, but I agree, it sounds like headspeed to me as well. I had tweak my throtle curve @ 1-3 to be a few points more. May suggest u check the programming on yr esc? I am wandering if yr spool up is too fast??? Just an idea to look at. I adjusted my settings to allow a sofTer start up and a little patients for the head speed to spool up.The only thing I am trying to figure out now is a slight drifting I experience during hoover. trimming dosent correct it. any suggestions fm those great minds here will be appreciated.

FlyingHigh 450 · 03-01-2010, 11:08 AM

+1 on taking the headspeed up.The Trex 450 Sport has a very stiff head and needs alot of headspeed,mine ran awesome with no vibes or wobbles at 0-60-75-85-100 and idleup was a flat 85%.

yakflyer · 03-01-2010, 01:06 PM

Here's a thought, is there any possibility your belt is not set to the correct tension? I've notice mine would do that if it was too tight.
Check and see & save a few more $$$

teef_au · 03-01-2010, 04:18 PM

This thing is a sport, so unless he bought a custom pinion it has a 14 tooth coupled to a 3550KV motor. IT can develop enough head speed but as others have said the throttle curve is way too tame and this is not the first time I have seen a properly set up sport suffer from this.

Bottom line - 0 - 80 - 100 is not unreasonable. Normal pitch curve of 40 - 50 - 100 is also what I use.

02-24-2010, 03:36 PM	#2
d_adam Registered Users Join Date: Apr 2007 Location: Bytom, POLAND	not depend of head speed but it happens during hover in normal flight? nonsense You said that when you increased throttle curve, it still vibrate ? ... when you increase enough the curve will be the same as idleup so non sense x2 increase your throttle curve.... __________________ Best regards, Adam Tornado Fuel, JR Radio,

02-24-2010, 03:45 PM	#3
Wolfpackin HF Support My HF Map location Join Date: Nov 2007 Location: Eagle, CO	Look at that...two guys from Poland. +1 on possibly low headspeed. What are your throttle & pitch curves and what size pinion? Did you check or replace the main and feathering shafts? Those can bend on just a hard landing. __________________ Zen and the Art of Helicopter Maintenance Blade 400: E-flite 420H/35X ESC, AR6100e, HS65HB x 3, G401B/DS290G. (Ret.) CopterX 450AE V2: 430XL/35X ESC, AR6100, HS65HB x 3, LTG2100T/HSG-5084MG. T-Rex 550E V1 Classic Flybar: 600MX/BL70G, AR6200, DS610 x 3, Quark/DS650, 16t/520mm blades.

02-24-2010, 03:47 PM	#4
d_adam Registered Users Join Date: Apr 2007 Location: Bytom, POLAND	he did mainshaft from plasticine __________________ Best regards, Adam Tornado Fuel, JR Radio,

02-24-2010, 03:53 PM	#6
life2short1971 Registered Users Join Date: Jan 2009 Location: Fort White,Florida	__________________ Scott Trex 500 / /3026-1600/CC Ice75 /3G /Ds510's/Torsion 430 fbl's Trex 450 pro/HK2221-8/ Ice 50 /HS-5065MG/325D's/Kbdd's

02-24-2010, 03:55 PM	#7
d_adam Registered Users Join Date: Apr 2007 Location: Bytom, POLAND	No worry, I will buy new one for YOU !! OK Stop my friend I think, you are very nervous Who can help him ? Is here a psychiatrist ? Joke OK, ok .... I forget that It isn't polish forum __________________ Best regards, Adam Tornado Fuel, JR Radio,

02-24-2010, 03:59 PM	#8
jaywhy Registered Users My HF Map location Join Date: Apr 2007 Location: San Diego	That type of vibration is referred to as `porpoising` (like the animal) - and it's from either too low of a head-speed or something too tight like the blade grips. Maybe something in the tail drive too, but I'm not positive about that.

02-24-2010, 03:59 PM	#9
eDeK Registered Users My HF Map location Join Date: Apr 2008 Location: Belgium	d_adam,Why you are saying it now,in his thread rather to help him in real. Stop trolling. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

02-24-2010, 04:50 PM	#11
zen Registered Users My HF Map location Join Date: Feb 2007 Location: Berkeley, California	Khiledim— the heli in the video shows the typical movement when there is not enough head speed. Instead of 55% at mid-stick go to 80% or more. No less than 70. If you dial it up to that range the up-and-down motion of the tail ought to stop. The other factor is the size of the pinion gear on the motor. 11 tooth for hovering and basic maneuvers, 12 tooth for more aggressive upright flight plus loops, rolls, and flips. To give you some idea I fly a 450 SE (V1) with a 12 tooth pinion on an Align 430 L motor. The throttle curve at center stick in both normal and idle up is 85%. At zero pitch (center stick) the head speed is 3,000 RPM, dropping to 2,800 or a little less when it lifts off. Regards, Glen __________________ Trex 450 SE V2 T-rex 500 ESP

03-01-2010, 08:07 AM	#12
yakflyer Registered Users Join Date: Dec 2009 Location: Georgia	some good info here, but I agree, it sounds like headspeed to me as well. I had tweak my throtle curve @ 1-3 to be a few points more. May suggest u check the programming on yr esc? I am wandering if yr spool up is too fast??? Just an idea to look at. I adjusted my settings to allow a sofTer start up and a little patients for the head speed to spool up.The only thing I am trying to figure out now is a slight drifting I experience during hoover. trimming dosent correct it. any suggestions fm those great minds here will be appreciated.

03-01-2010, 11:08 AM	#13
FlyingHigh 450 Registered Users My HF Map location Join Date: Feb 2008 Location: Macomb co,Mi	+1 on taking the headspeed up.The Trex 450 Sport has a very stiff head and needs alot of headspeed,mine ran awesome with no vibes or wobbles at 0-60-75-85-100 and idleup was a flat 85%. __________________ Started the hobby in Feb of 2008 To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. .

03-01-2010, 01:06 PM	#14
yakflyer Registered Users Join Date: Dec 2009 Location: Georgia	Here's a thought, is there any possibility your belt is not set to the correct tension? I've notice mine would do that if it was too tight. Check and see & save a few more $$$

03-01-2010, 04:18 PM	#15
teef_au Registered Users My HF Map location Join Date: May 2009 Location: Brisbane Queensland Australia	This thing is a sport, so unless he bought a custom pinion it has a 14 tooth coupled to a 3550KV motor. IT can develop enough head speed but as others have said the throttle curve is way too tame and this is not the first time I have seen a properly set up sport suffer from this. Bottom line - 0 - 80 - 100 is not unreasonable. Normal pitch curve of 40 - 50 - 100 is also what I use. __________________ *"It is said that the big thing on top is a rotor - it's not it's a cooling fan for the pilot. We know this is true because if it stops spinning you can actually watch the pilot sweat."*

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