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solentlife
Extreme 3D
Joined: 30 Dec 2010
Posts: 872
Location: Latvia / UK
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 Posted: Sun Jun 26, 2011 6:48 pm
Post subject: MTBF ............ fatigue and time to change ? |
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Well ... seems that numerous mishaps, hard landings, crashes etc. are starting to catch up with my 450.
I am getting stupid failures of ball links, threads etc. ... ie flybar control arm ball link breaking of .... main rotor holder ball link thread stripped ..... odd plastic links unclipping of balls ......
Most of course happen when it's in the air and not much you can do to save the heli !
I've now changed whole head for new and will replace near all on old to renovate.
Anyone else had similar ?? I put it down to fatigue / stress and in time it fails.
Considering the loads and stress that must prevail on such machines ... is it any wonder ?
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If you don't crash - you ain't flying !
Fast learning to be 450 Heli Repair specialist !
Have : 2ch Bumblebee,
Co-Ax Syma S006 Alloy Shark
2x Clone 450 SE V2
+ fixed wing stuff ...
Returning to RC after 20 odd yrs away .. Ex Display flyer. |
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tombo242
Extreme 3D
Joined: 04 Nov 2008
Posts: 3633
Location: Santo Estêvão, East Algarve, Portugal. 76, but still feels 18.
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Posted: Sun Jun 26, 2011 6:51 pm
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Agreed there Solentlife,
The way some helis are thrown about, it's amazing that they last the flight.
Tom.
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admiral
Extreme 3D
Joined: 20 Mar 2009
Posts: 695
Location: Brisbane, Australia
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Posted: Mon Jun 27, 2011 3:52 am
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Hi Solentlife,
As some of Helicopters my get older I have found that weekly checks and preflights are becoming more important, it's amazing how often you find a loose screws or bolts, missing nuts, cracked ball links.
I think it's just the nature of the beast, a complex piece of equipment with rapid moving parts needs regular inspection like their full size counterparts.
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Keep your rotors spinning
Keith |
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platinum
Extreme 3D
Joined: 31 May 2011
Posts: 272
Location: Bangkok Thailand
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Posted: Mon Jun 27, 2011 5:05 am
Post subject: |
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| admiral wrote: |
I think it's just the nature of the beast, a complex piece of equipment with rapid moving parts needs regular inspection like their full size counterparts. |
I agree with ...admiral.
My fellow 450 the blades and grips flown off inflight. Lucky no body got hurt.
platinum
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/Goal : relaxed flying with the least fixing.  |
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solentlife
Extreme 3D
Joined: 30 Dec 2010
Posts: 872
Location: Latvia / UK
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Posted: Mon Jun 27, 2011 8:34 am
Post subject: |
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Pre-flights and general tightening etc. in fact - my 1.5mm hex driver is now worn out ... I've had to resort to grinding back the worn bit to good square section. These are NOT chinese cheap jobs either !
I have a complete new set of drivers in post coming to me.
My 450 is about 6months old ... and I was not expecting such failures yet ...
_________________
If you don't crash - you ain't flying !
Fast learning to be 450 Heli Repair specialist !
Have : 2ch Bumblebee,
Co-Ax Syma S006 Alloy Shark
2x Clone 450 SE V2
+ fixed wing stuff ...
Returning to RC after 20 odd yrs away .. Ex Display flyer. |
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solentlife
Extreme 3D
Joined: 30 Dec 2010
Posts: 872
Location: Latvia / UK
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Posted: Wed Jul 27, 2011 1:35 pm
Post subject: |
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No g'tee of quality !
With my 450 suffering various silly mishaps despite checks before flights ... I decided to invest in a second set of hex drivers ...
As we all know various screws on the frame, feathering shaft ... requires having 2 drivers at same time. Well I bought what was apparently high quality not cheap drivers.
First job with the most common sized driver we need ... 1.5mm - the 1.5mm bit snapped of ! I couldn't believe it.
But the major problem in this fatigue matter is the screws themselves I reckon. Unfortunately not all the silver screws can be replaced with superior 12.9 machine jobs and I'm finding it's generally those that are failing. One common one is the self-tappers into back of frame to secure the tail support rods. Being self-tappers into CF frame - you cannot locktite them, If you superglue them = then you ruin the frame.
One modification that seems to be working ....... a replacement rotor head assembly had cross point screwdriver instead of 1.5mm hex driver heads ... the balls etc. have stayed tight and no more rounding out with driver.
Another guy who built a CopterX version - he had cross-point screwdriver heads as well and is very pleased with them.
_________________
If you don't crash - you ain't flying !
Fast learning to be 450 Heli Repair specialist !
Have : 2ch Bumblebee,
Co-Ax Syma S006 Alloy Shark
2x Clone 450 SE V2
+ fixed wing stuff ...
Returning to RC after 20 odd yrs away .. Ex Display flyer. |
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platinum
Extreme 3D
Joined: 31 May 2011
Posts: 272
Location: Bangkok Thailand
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Posted: Thu Jul 28, 2011 5:27 am
Post subject: |
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| solentlife wrote: | No g'tee of quality !
...........
One modification that seems to be working ....... a replacement rotor head assembly had cross point screwdriver instead of 1.5mm hex driver heads ... the balls etc. have stayed tight and no more rounding out with driver.
Another guy who built a CopterX version - he had cross-point screwdriver heads as well and is very pleased with them. |
It sounds interesting. Thanks for sharing.
platinum
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/Goal : relaxed flying with the least fixing. |
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tombo242
Extreme 3D
Joined: 04 Nov 2008
Posts: 3633
Location: Santo Estêvão, East Algarve, Portugal. 76, but still feels 18.
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Posted: Thu Jul 28, 2011 4:59 pm
Post subject: |
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| solentlife wrote: | | One common one is the self-tappers into back of frame to secure the tail support rods. Being self-tappers into CF frame - you cannot locktite them, If you superglue them = then you ruin the frame. |
I use a smear of 'Blue Tack' on the threads of these. Easy to take out with tools but not so easy for vibration to loosen them.
(For those who do not know 'Blue Tack' is a sort of 'sticky' playdough used to put posters etc on inside walls.)
Tom.
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Dumb Thumbs
Extreme 3D
Joined: 01 Jan 2008
Posts: 811
Location: USA, N.J., Middlesex county
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Posted: Sat Jul 30, 2011 9:00 am
Post subject: |
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When I built my clone 450 I tossed the links in the trash right off. Compaired to the quality of the link parts of the Align 450 I have, I just didn't trust the Hobby King junk and used Align links. Never had a Align link fail yet, but I do keep an eye on them fore ware & tare (lots of tare more then ware) 
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Next Level 650 Quad Copter, T-Rex 500, 450SEv2 & 250
HK 450
Blade CP Pro (deceased), CX3, MCX, MSR,
MCP X, 120SR, MSR X, MQX
Pro Boat-Miss Geico & ShockWave, a few planks & a HPI Baja 5B SS gas buggy.
AMA#900889 |
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solentlife
Extreme 3D
Joined: 30 Dec 2010
Posts: 872
Location: Latvia / UK
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Posted: Tue Aug 16, 2011 3:40 pm
Post subject: |
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| Dumb Thumbs wrote: | | When I built my clone 450 I tossed the links in the trash right off. Compaired to the quality of the link parts of the Align 450 I have, I just didn't trust the Hobby King junk and used Align links. Never had a Align link fail yet, but I do keep an eye on them fore ware & tare (lots of tare more then ware) |
Basically links don't fail - its the rounding out of the driver slot.
I have had a couple of plastic links come of balls ... but I think I maybe clicked those on wring way round when adjusting and destroyed the ridge moulded in them.
_________________
If you don't crash - you ain't flying !
Fast learning to be 450 Heli Repair specialist !
Have : 2ch Bumblebee,
Co-Ax Syma S006 Alloy Shark
2x Clone 450 SE V2
+ fixed wing stuff ...
Returning to RC after 20 odd yrs away .. Ex Display flyer. |
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