servo-issues with stretch-version?

[macem]

dear all, anybody heard something about servo-issues with the stretch-(flybar-)version?

mine crashed today after servo-breakdown, just some flights after upgrading to the 350mm-blades... it seems, my 10-hours flighttime-old hitec hs65-hb servos (4,8/6V (Ncm) 16/18) did not stand the forces of the longer blades...

with the 325er-blades (flybar) i used to do up to 30 hours beginning 3d with the hs65hb until i replaced them ... so i was really surprised by the servo-failure...

i realised some stearing-weakness the flights before, but unfortunately i did not blame the servos for that...

for now, i would recommend also to upgrade the servos in case of upgrading the whole system...

macem

[hakiem]

I had around 30 flights flybar stretched, with 2400/2500rpm, soft 3d and using 65mg. Haven't had any problems yet, will change to beastx in a few weeks time.cheers !!

[macem]

... 30 flights is not that much... also 2500rpm

... i guess, my servos shifted the blades for 150 flights at 3500 rpm, the last 30 flights with the 350-blades...

it seems to me, the force to the servos caused by the rotating blades is not in a direct ratio to the lenght, but exponential... we miss the longtime-experience with 350-blades...

macem

[Thunder Fighter]

Normally flybared helis put much less strain on servos from both the frequency of updates and the load which is geared down by the link ratios in the head so I would expect to see FBL versions buring up servos all over if there was an issue. There are a few other 350mm blade heli's out there and again i haven't seen any reports of this being a common issue.

I can say that stretching the full size Protos from 425 to 475mm blades hasn't caused a rash of servo failures, even with FBL setups. We still use mini size servos like the DS510 with no issue and people have many hundreds of flights on these setups.

//Dennis

[macem]

thank y dennis,
altough - if you are right i have to look for something else to blame for the crash now...



macem

[hakiem]

Originally Posted by macem

... 30 flights is not that much... also 2500rpm

... i guess, my servos shifted the blades for 150 flights at 3500 rpm, the last 30 flights with the 350-blades...

it seems to me, the force to the servos caused by the rotating blades is not in a direct ratio to the lenght, but exponential... we miss the longtime-experience with 350-blades...

macem

lol..3500rpm ? you are really pushing it hard. I could not even dare to go beyond 3000rpm, the sound of it is just too scary for me !!

[Thunder Fighter]

Originally Posted by macem

thank y dennis,
altough - if you are right i have to look for something else to blame for the crash now...



macem

Well a servo can still die and cause a crash but I just haven't seen any evidence from elsewhere that moving from 325 to 350 blades makes them burn out really quickly.

//Dennis.

[macem]

Originally Posted by hakiem

lol..3500rpm ? you are really pushing it hard. I could not even dare to go beyond 3000rpm, the sound of it is just too scary for me !!

... too scary? so, never, never, never watch darios mini-performance in the vid there with sound on ...

http://www.helifreak.com/showthread.php?t=335615

macem

[macem]

Originally Posted by macem

....

i realised some stearing-weakness the flights before, but unfortunately i did not blame the servos for that...

for now, i would recommend also to upgrade the servos in case of upgrading the whole system...

macem

i would like to modify my original assumption about too weak servos in the stretch-version, causing the crash i posted before... there may have been another reason for the stearing weakness i noticed some flights before thecrash, it concerns a maybe dickey (half broken, late-effect of another crash some weeks ago..) flybar carrier causing some irrational effects until it breaks completly...

so the damaged flybar-carrier i have to replace now could have been the reason not the consequence of the crash... and the other way round for the broken servogears ...



anyway, hope to be in the air tomorrow... with new servos and new flybarcarrier...


macem

[hakiem]

so, what servo did you end up buying ?
I'm a bit confused on what servo to get once I convert to FBL. My personal preference has to be the 5065, but with the ds92 coming and cheap reliable savox is in the market, I might just see what the ds92 is capable of...

[macem]

... i orderd the cheap savox sh 0254, because it is very strong - i thought i need rather power than speed... unfortunately some days before mks brought his ds92 in the market... ... outherwise this would have been my first class servo ...

macem

[rablett]

I have 2 FBL, one stretched, one not. I am running HS-5065MG in both and have had no problems. I would like to try the MKS servos and have a set for one of my big Protos to try out.

[macem]

... i apologize for reactivating this thread, but i think i solved my servo-problems described at the beginning - and this perhaps would be of interest for some others here...

i did realy have some stearing-weakness using the 350blades, and i blamed the servos for that and switched to stronger ones - this was counterproductive ... in fact, the 3a(5a)-bec in the esc i use (robbe roxxy 950-6, 50a) seems to be to weak in combination with 4s-lipos: the bec got hot and reduced power as safety-function, this caused the servoblackouts ... and the stronger servos thigtened th problem...

i hited on it because of some telemetric datas of my new graupner-hott-tx/rx-system - the first telemetric data i ever had... they showed a steep fall of voltage (to 3,2 volt instead of 5,5). now i installed an ubec (switch-mode), and the telemetric datas said something about a minimum of 4,6 voltage at the servo-current-supply ...

so finally i would recomend to boost rather the bec than the servos when using 350er blades (in combination with 4s)... it is not a servo-issue, there could a bec-issue using the stretch-version

macem

[HighFreq]

No problems with stock esc


Corrado

[desertstalker]

Originally Posted by macem

so finally i would recomend to boost rather the bec than the servos when using 350er blades (in combination with 4s)... it is not a servo-issue, there could a bec-issue using the stretch-version

It should be noted this is not needed using the stock MSH/YGE esc. The BEC is already switching and will handle 4-6S just fine. Mine barely gets warm (jammed into the nose under the battery tray) and i have it governed at 60% TC.

[macem]

Originally Posted by HighFreq

No problems with stock esc


Corrado

......

yess... that is probably correct, with my roxxy-esc i am something like a msh-career-changer... but now and then i can handle tips and even learn qickly ...

macem