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01-06-2013 04:27 PM  5 years agoPost 1
Sherman89

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Morriston Fl

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I am working on large cuban 8's and when immediately after I complete the roll out on the 45 down line and before I go from neutral pitch to positive pitch I get a small oscillation----woo-woo-woo, if I go slower it does not oscillate only at speed but to keep the maneuver congruent I need to speed----it only happens from left to right with a right hand roll out-----right to left with the left roll out there is no oscillations at all. When flying from right to left I use the right hand roll because I do not seem to be able to control the left hand roll with the correct exit and collective matched properly. Any ideas??

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01-06-2013 07:09 PM  5 years agoPost 2
Salesmanheliboy

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Nashville, TN

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FBL or FB ?

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01-06-2013 09:42 PM  5 years agoPost 3
Sherman89

rrApprentice

Morriston Fl

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FBL

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01-06-2013 09:51 PM  5 years agoPost 4
Santiago P

rrProfessor

South West, Ohio

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Setup...

What heli and what FBL system?

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01-07-2013 10:41 AM  5 years agoPost 5
Sherman89

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Morriston Fl

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align/chaos 600 with align FBL and a AR7200BX---600mx 1220kv---stock gears----belt drive with 95mm tail blades and Edge 550 main blades---HS-2250. I for got to mention that with the same set-up with 600 blades the heli does not develop the oscillation.

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01-07-2013 10:42 AM  5 years agoPost 6
Sherman89

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Morriston Fl

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The heli tracks straight both in and out but for the oscillation at the completion of the right hand roll.

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01-07-2013 11:30 AM  5 years agoPost 7
Thomas L Erb

rrKey Veteran

Alliance ohio

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Have you done just straight level rolls the same way to check for this problem as well? Please discribe oscillation.if you fly thumbs be sure you are not doing a momentary stick release that may give you stick bounce. Just some thoughts

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01-07-2013 02:29 PM  5 years agoPost 8
marcosp

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Buenos Aires, Argentina

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Could be a main gain problem as well, gain can be right on 600s and not on 550s. Check roll stops even stationary and adjust gain to the point were you have no bounces. You don't need to roll it, sharp ail inputs will show the stop bounces in a hover.

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01-07-2013 03:26 PM  5 years agoPost 9
Sherman89

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Morriston Fl

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No bounces on stationary rolls----on the high speed rolls the heli does not oscillate----the oscillation is a very mild forward/back porpoise with the woe-woe-woe sound. You have to look carefully or you will miss the oscillation but you can definitely hear it. I use a tray radio and pinch the sticks----I have about 45 years of RC with several years of IMAC so I don't think it is PIO. My TSA 700 with an AR7200BX on the same tx and basically set up the same way does not oscillate. I think it may be HS related as the 550 blades are turning about 150-200 rpm more than the 600 blades and that is the only difference and it has something to do with the right hand 1/2 roll as compared to the left hand roll which does not oscillate.

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01-07-2013 04:50 PM  5 years agoPost 10
Santiago P

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South West, Ohio

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I am starting to think is a dampening (Lack Of) resomance.
Is it a standard head (not DFC)?

How stiff or loose are the head dampeners?

Santiago

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01-07-2013 05:17 PM  5 years agoPost 11
Helipilot01

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ColliervilleTn

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I had a similar problem with the same equipment your using except it was with the 600mm blades. I could do slow rolls and the nose/tail would stay straight. However, when I tried to do several fast rolls together, I could see the nose pitching up. What I found was that the swashplate was bottoming out at extreem throws. I backed off the throw of the 7200BX for AIL and now rolls are straight no matter how fast or slow.

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01-07-2013 09:53 PM  5 years agoPost 12
Sherman89

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Morriston Fl

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It is the standard Align FBL head----the swash is not bottoming out and the nose is not pitching up it is a very mild oscillation that is porpoise fore/aft and not side to side. MPV you may have pointed me in the right direction----it is a possibility that the dampeners may not be rigid enough for that portion of the maneuver and it is the right roll that may be putting more force on the head creating the oscillation because the dampeners can not contain the extra strain.

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01-07-2013 10:55 PM  5 years agoPost 13
Sherman89

rrApprentice

Morriston Fl

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What I do not understand is the fact the only difference is the blade length and 150-200 rpm increase on the HS but must be enough to set up the oscillation.

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01-11-2013 10:48 AM  5 years agoPost 14
Sherman89

rrApprentice

Morriston Fl

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New dampeners on order.

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01-12-2013 10:57 PM  5 years agoPost 15
Sherman89

rrApprentice

Morriston Fl

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I put in a set of the 80 align dampners (waiting for the FBL dampners) and wowow what a difference----the 80 is way too soft for FBL----not even close!!!!

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