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Crashed? Discussion and Photos > sceadu crash question
 
 
coony278
Senior Heliman
Location: oxford, ms.

i was flying my sceadu today and at teh end of the flight i was in a hover fixin to land. when the blades seemed to go into a flutter !!!! then it started a fast decent to the ground comemeced to boom strike and do the funky chicken dance into the howling chicken ( any way you get the picture)

well the only thing that was wrong on the head besides the blades beat off and the flybar twisted violently was that the 9202 was stipped and wrote this crash off too the servo stripped and the blades just went wild!!! i vowed right there at the feild that a 9202 was not a good enough servo for the pitch on a 30 heli let alone a 50. And that i would never put another one of them junk servo's in my helicopter .

well after the shock and the disapoinment of another heli taking a dirt bath , my brother says that there is no way that a stripped servo could cause the blades to go into a fluttering wild madness that the heli did!!

So my question is simple , will a stripped servo on the pitch let the blades flutter ???? or do you think something else was the culprit. the heli was flying beatifully before this happened. and i just went over every bolt before i flew it today to make sure all was tight. any input would be appreciated , thanks

Chad
04-05-2003 Over year old.
 
 
Rappy
Senior Heliman
Location: Belgium

The S9202 servo is not te cause from the flutter, its can be alot off things ...

Bad blades
Lost ballink on the head
Bad spindle ( had this ones afther some heavy 3D )
Bent flybar

B.t.w.... i use the S9202 for some time one my raptor 60, and i fly 3D with them, use this on cycle/pitch/gas/rol, and they hold great, not so great as my other raptor with S9151 digitals, butt they are good servo's.

Regards

Chris
04-06-2003 Over year old.
HOMEPAGE  
 
 
coony278
Senior Heliman
Location: oxford, ms.

belive it or not all the ball links was still conected. now it tore up a bunch of stuff but the head was virtually undamaged other than a bent feathing shaft and broke head button.

so if a the pitch servo stripped in flight the blades would just stay in there same path as were before the servo stripped ? now i was not really downing a 9202 just was upset because i cant seem to locate the cause of this crash.

Chad
04-06-2003 Over year old.
 
 
fitenfyr
rrProfessor
Location: Port Orchard, Washington

Yep...

Chad,
I would most defiantely say the 9202 could have caused your flutter.
There is a for lack of a better word "dynamic" type of situation in the collective system of the Sceadu. No one can really put their finger on EXACTLY what causes the flutter even Jeff Green is stumped by some, but MOST of them are due to improper installation of the collective servo or just plain overworking the servo.

Sounds to me like you had a bit of both going on.

Couple things to look at for the future. The 9202 IS capable of handling the collective for mild 3D IMO, but beyond that I would look for a 9204 or something of similar design and torque for the Sceadu.

1. How free is your linkage and collective pitch system. Everything should move very easily when not connected to a servo. If this is too tight that could cause the 9202 to fail due to excess strain on the system.
2. Did you mount the servo with the metal plates? Was it REALLY tight?

If either of these were present then they caused the servo to fail prematurely IMO. The other things is you could have just had a bad servo or just plain tired and worn out.

I use 9202's on my cyclics and a 9204 on my collective. I have also used a Hitec 605 which wore out pretty quick on my collecitve. If you look at the specs and such you will find it is a similar servo with better gears IMO (helical cut instead of straight cut. More holding power and torque with less effort)

Either way replace that servo and re-build it.

BTW a little birdy told me that a new head is in the works for the Sceadu that will work awesome with just a 3001 servo. We shall see sounds like a winner and yes the source was VERY reliable.

Jason Stiffey
Fly Fast....Live Slow...
04-06-2003 Over year old.
HOMEPAGE  
 
 
coony278
Senior Heliman
Location: oxford, ms.

thanks for the input fitenfyr, the servo was not mounted with them metal hold downs i will check the rest of your sugestion on the rebuild. I order 2 9151's for the collectives on both my sceadu's hopefully this problem wont ever rear its ugly head again

Chad
04-06-2003 Over year old.
 
 
fitenfyr
rrProfessor
Location: Port Orchard, Washington

Haven't seen that

Seneca,
I could have missed it in the book, but I know that has been the suggestion from Altec regarding the collective.

DEFINATELY put the metal plates on. That was most certainly the demise of your servo gears and the cause of the flutter.

Jason Stiffey
Fly Fast....Live Slow...
04-06-2003 Over year old.
HOMEPAGE  
 
 
Jim C
Veteran
Location: Indiana, PA

arent the metal collective hold down plates an attempt to correct the woof and poof?? i spent the money and bought the massive 9206 for the collective on my ship... the only prob i have right now is that they supplied me with 570 blades... head speed goes to the moon if i set the motor to optimum(slightly rich of peak) i hope the 600 sabs i got commin in the mail help some.... also.. the only other complaint i have are the weakness of the flybars ..... they bend if you just look at them wrong... quick has a 4 mm conversion and they seem harder than the stock 3mm flybars.. im looking at maybe getting that up grade... also.. i suggest getting a bigger servo... AND USE THOSE METAL PLATES!!!!!!!!

jim

http://jimsrc.com
04-07-2003 Over year old.
HOMEPAGE  
 
 
fitenfyr
rrProfessor
Location: Port Orchard, Washington

Ummmm.

No. The metal plates on the Sceadu are part of the original design.
I think you are thinking about the Raptor. They told alot of owners to start using them after they were initially not needed.

The Sceadu says to use them from the start.

Your SAB's will turn it into a new ship. Those 570's are just too small and semi-symetrical to boot.

Jason Stiffey
Fly Fast....Live Slow...
04-07-2003 Over year old.
HOMEPAGE  
 
 
Jim C
Veteran
Location: Indiana, PA

 yeah yeah yeah yeah yeah yeah yeah..... just got my shiny new parts today!!!!!!!!!!!!!!!!!!!!!!!! cant wait to fly again... just as soon as i can get some colorful burny stuff.. hey fitenfyr, i just put in the dtds, am i gonna have to set up the heli again or should it not really change??? just a quick eyeball, it looks ok, but i didnt have the time to go back over the set up yet??????

jim

http://jimsrc.com
04-07-2003 Over year old.
HOMEPAGE  
 
 
fitenfyr
rrProfessor
Location: Port Orchard, Washington

Nope..

Only thing that may change is a tad bit of throttle curve adjustment due to the increased drag of the heavier gears.
I don't recall making any changes on mine though.
Leave it the same and fly it. The DTDS is great. First Autos with the driven tail are beautiful and it doesn't loose much energy at all with a good set of 600's installed.

Jason Stiffey
Fly Fast....Live Slow...
04-08-2003 Over year old.
HOMEPAGE  
 
 
Jim C
Veteran
Location: Indiana, PA

fitenfyr: thanks for the info man... that is what i was hopin to hear!!!
what are your thoughts on the fly bar stiffeners?? yay or nay?? i was looking into getting a set of those also.... my first heli and im goin crazy on the upgrades already......
jim

http://jimsrc.com
04-08-2003 Over year old.
HOMEPAGE  
 
 
fitenfyr
rrProfessor
Location: Port Orchard, Washington

I don't use them..

I have just put the metal mixing control arms and flybar control arms on.
Buddy of mine has put the 4mm stuff on with a 60 flybar (not sure which) and V-paddles. He says it has much more cyclic authority so I would imagine the flybar stiffners would do something similar but not to the extreme his was/is. He put it in the dirt last time I flew with him and I didn't get to try it out. He also wasn't going to put it back together right away so I don't know if he has yet.
I run MAH mains so they make the head pretty quick by the nature of the blade so I don't use anything else on the flybar.
However I have been giving some thought about putting the 4mm kit on and giving it a try.
The stock flybar is a bit flexy to me on the bench.

Jason Stiffey
Fly Fast....Live Slow...
04-08-2003 Over year old.
HOMEPAGE  
 
 
coony278
Senior Heliman
Location: oxford, ms.

thanks for all the input guys i sure hope that these little helpfull hints keeps my scooby in the air this time !!! keep your fingers crossed !!

Chad
04-08-2003 Over year old.
 
 
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Crashed? Discussion and Photos > sceadu crash question
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