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HomeAircraftHelicopterHIROBOOther › main blades oscillating on Sceadu
07-15-2002 06:40 PM  16 years agoPost 21
tadawson

rrElite Veteran

Lewisville, TX

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I also had this problem on my Sceadu 50, and spoke with Jeff Green about it, and his suggestions fixed my problem almost instantly. Check your mixing arms on both the seesaw and washout for
slop in the bearings - see if the arms will move
about the bearings. Mine were pretty sloppy right out of the box, and since these arms connect collective into the head, this can happen. If this is the case, what Jeff suggested that I do was to remove the little top-hat shaped sleeves that the bearings slide over, and to shorten them a bit with some gentle filing until the arm will run with no slop whatsoever when it is put back together. I did this
on the seesaw arms, washout arms, and (I think - not sure) one of the other bellcranks with the closely spaced bearings. I have not seen the problem since . . . . and the cose was $0!

- Tim

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07-15-2002 08:00 PM  16 years agoPost 22
fitenfyr

rrProfessor

Port Orchard, Washington

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Mixture...
Stet,
The low end and the top end work together on a 2 needle carb to get the hover mixture. So if you have good transition but lean hover then richen the top end a tad to richen the mid range. You may also have to adjust the low end to get that perfect balance.
Got to love those 3 needle carbs
I personally don't think your gyro/tail wag is due to the gyro mounting. I and many others fly with the sensor mounted on the servo tray with 0 problems.
I would try to isolate the engine "vibration" first before you go moving things around. IMO that is the source of your wag.

Hope that helps

Jason Stiffey
Fly Fast....Live Slow...

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07-16-2002 09:48 PM  16 years agoPost 23
shawkshelia

rrNovice

Atlanta

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oscillating main blades
After checking most, if not everything everyone has replied with, I find that the most "free" play seems to be from the point at which the radius arms(pork chops) attach to the swash up to the mixing arms and washout unit, to the flybar control arm. No matter what I do, lengthen, shorten, tighten the screws through the mixing arms into the washout unit....the free play is still there!!!??? The fit between balls and link ends are all good...I'm at a loss trying to figure where the slop is. Feathering axel...tight. Blade grips...tight Head to main mast....tight...Collective servo....solid as a rock....

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07-17-2002 11:01 PM  16 years agoPost 24
shawkshelia

rrNovice

Atlanta

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Thanx, Vetrider had posted a similar suggestion and I will try this as well. Thanks to all that have given input, your help is most appreciated.
I'll give an update as soon as I know something positive myself.

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07-18-2002 01:10 AM  16 years agoPost 25
squirrel

rrVeteran

South Whitley, IN

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The blade grips were flipped on the Sceadu 50 and the radical blade flutter stopped. It was only tested for a few flights, but it looks like a potential cure.

squirrel

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07-18-2002 09:11 PM  16 years agoPost 26
shawkshelia

rrNovice

Atlanta

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All my bigger machines, Bergen 60 and 80 have the collective arm leading and now the Rappy does too!!! There must be something to it.
I "do" know it affects the input timing for cyclic inputs.

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07-19-2002 09:54 AM  16 years agoPost 27
elad

rrApprentice

beer sheva (in south) israel

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yes yes yes
I have thise problem in my sceadu 50 I'm useing Tg blades 585 mm
the heli flyes good in "normal" flight , but when I'm doing some
3d and in particular when i'm getting near 0 degree I'm haveing
bad vibs do to out of tracking blades.
I have to say that it's not a result of abuseing it's happen also if i fly invert and desent .... when getting near 0 degree it starts.....
I don't believe that it's over speed problem.
thise heli suck's
that the thruth.
waste of money...


IF you want a good solution buy a freya.

and another thing .... thise heli bring my bad lock
see:
http://www.geocities.com/elad_heller/heli.html
anybody saw a mid air high altitude collision ???????


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07-19-2002 09:22 PM  16 years agoPost 28
shawkshelia

rrNovice

Atlanta

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Looks like the "plank" got the worse of the deal. The Sceadu look like it is laying on its side taking a break! No pun intended.

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07-20-2002 12:36 AM  16 years agoPost 29
fitenfyr

rrProfessor

Port Orchard, Washington

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Blades....
Elad,
Now that you mentioned them.
US flyers have found that blades less than 600mm on the OS 50 are not easy to govern. I would be betting that the problem lies in your mains. Try a different set of blades. 600's if you can.

Jason Stiffey
Fly Fast....Live Slow...

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07-20-2002 04:24 AM  16 years agoPost 30
Terry Moore

rrNovice

Yuma Arizona

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Woof
DIDO's to what fitenfyr posted!!

Terry


SCEADU 50 JR IMZ 50S

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07-21-2002 06:56 AM  16 years agoPost 31
Stet

rrElite Veteran

Key Largo FL

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think I found the problem(s), I hope
1) Start shaft runout was 15 thou at the tip, caused by the hub not being perpendicular by 3+ thou at the OD. Sanded it on a flat to correct it, now runout at the tip of the shaft is 1.5 thou, that should help

2) Engine mount tophat washers were installed with the washer between the frame and the mount, figured this out when I went to install the HHI frame brace, and initially thought Irwin did it again by screwing up the geometry (like the early Raptor carbon frame braces). Switched the washers to outside the frame and the brace fit. The washers reduced the area of contact for the engine mount. My buddy bought it used and assembled (wrong).

3) Balanced the fan, but I doubt that will have a measureable effect

4) Added the frame brace, and moved the boom struts to the holes by the landing gear.

I hope and expect that the airframe will shake much less now, if it doesn't, I give up.

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HomeAircraftHelicopterHIROBOOther › main blades oscillating on Sceadu
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