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Other › Blade CP Pro: boom strike before leaving the​ground
08-10-2007 03:38 PM  10 years agoPost 1
gpontis

rrNovice

Palomar Park, CA

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I purchased a Blade CP Pro used. It came with a G90 and a set of plastic or fiberglass flat bottom blades. I have never seen this heli hover or fly at all (mistake #2). On a quick check it looked like the servos were all doing the right thing in response to the controls. I pinned the skids to the ground and spooled it up. It sounded fine at first, and then for some unknown reason there was a boom strike. I guessed that I must have bumped the cyclic or something. After putting it back together I checked the controls again and began to run it up. Same thing ! At around 80% throttle there was not enough lift to hover, and with just a slight increase in throttle there was a boom strike. I am quite sure that I did not touch the cyclic that time. Can someone say what is likely to cause this ?

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08-10-2007 05:08 PM  10 years agoPost 2
dignlivn

rrApprentice

Cullowhee,NC.

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Is the swash plate level?
The main shaft bent?
The Spindle bent?
Blades out of balance and
not tracking properly.

Try a set of wood flat bottom
blades also.

Bob

dignlivn

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08-10-2007 05:17 PM  10 years agoPost 3
Chowdher

rrNovice

Victoria, BC, Canada

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If you are at 80% stick and still arent in the air, there is something amiss with your setup.

It sounds to me like you have a programing mix issue. I think that by 80% you would see obvious signs of an imbalance that would be significant enough to cause a tail strike.

Are your control rods all the same length?

It's not just good... it's good enough

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08-10-2007 06:16 PM  10 years agoPost 4
gpontis

rrNovice

Palomar Park, CA

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Thanks for the thoughts.

Clearly there is adjustment needed when it is not lifting by 80% stick. The puzzling thing is that at 80% is looked like it was spinning nicely and had plenty of clearance from the boom, then 81% and blade hits boom.

The main shaft is certainly bent now. I just pulled it and will get a new one. (Maybe I should get a couple of them). I am also a little concerned about binding in the brass bushing between the swashplate and the main shaft. It is not sliding perfectly smoothly. Maybe it is due to the shaft being bent. I'll check that carefully on a new shaft.

Linkage looks good - all same length and servos working as expected when shaft is not spinning.

George

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08-10-2007 06:25 PM  10 years agoPost 5
Chowdher

rrNovice

Victoria, BC, Canada

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Another thought occured to me, as it happened to me when I copied one program from one chopper to another to save me set up time... and the collective channel was reversed and I really didnt notice it until I was on the line with it. So full up was really full down.

Cheers

It's not just good... it's good enough

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08-11-2007 12:45 AM  10 years agoPost 6
gpontis

rrNovice

Palomar Park, CA

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I am lucky that the LHS, only 2 miles away, has a good stock. I purchased and installed a new main shaft and treated myself to a swashplate assy while I was at it. Put it all back together with a new set of symmetrical wood mains. It did take some adjustment since I found it going from about 0 to 20 degrees positive. Also I double checked that all servos were going in the correct direction. When I got done the pitch range settled around +/- 10 degress, as best as I can tell using an E-Flite pitch gauge.

In ground testing without a boom ... it looks like the arc of the blades crosses the plane of the boom when full back cyclic is input. With full fwd it is slightly less deflection. Does this seem normal ?

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08-11-2007 02:27 AM  10 years agoPost 7
fenderstrat

rrProfessor

Aston,Pa

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well thats kind of a tough one as the heli is not supposed to get full collective inputs while secured to anything. under normal flight the tail would normally get out of its own way.......is your collective working properly? ie is the swash moving the right way? if you are actually giving neg pitch while secured things could get BAD quickly

Compass helis Support Team
PerformancePlusRC field rep
Mini Titan/SE
TEAM KBDD

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08-11-2007 02:50 AM  10 years agoPost 8
dignlivn

rrApprentice

Cullowhee,NC.

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What fender said.

Also, try lowering the Servo
ball link on the Front Servo.

Here is a link to a good set up
and baseline.

http://www.rcuniverse.com/forum/m_3...ey_blade/tm.htm
Thanks b davison !

Bob

dignlivn

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08-11-2007 02:52 AM  10 years agoPost 9
gpontis

rrNovice

Palomar Park, CA

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Can't apply full input on the ground ? I didn't realize that. In any case it seems to be flying more or less. I put the new DD tail on and took it outside and was able to hover and scoot around with normal amounts of control input. There was a little too much of a breeze to venture far, as least for my level of skill. But I think that it is flyable and the trim seems neutral.

As a final insult before hovering, I had a tail rotor strike on the upgrade tail fin and broke the front rib off. I thought that I read that the DD tail needed to be connected backwards, and did that without further checking. It spun like crazy, then as soon as the tail fin touch the ground it bent into the tail rotor. The effect was enhanced by my having pushed the TR directly onto the motor shaft, which minimized spacing. After it spun off I realized that it still needed the prop adapter for secure mounting and clearance from the fin.

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08-11-2007 03:00 AM  10 years agoPost 10
fenderstrat

rrProfessor

Aston,Pa

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DUDE!!!!I did the same thing once and I WAS PISSED I had just installed a new left side motor mount w/fin and new DD motor and prop... for some reason that motor was reverse wound or polarity (whatever)either way the heli did a NASTY piro, broke the fin to PIECES and fried a BRAND NEW DD motor and broke the prop....mine happened exactly as you described the fin caught on the ground,bent into the prop and the rest is history...the moral of the story is...even when installing things exactly as they were(motor/wiring) dont assume anything always test before a trial flight

Compass helis Support Team
PerformancePlusRC field rep
Mini Titan/SE
TEAM KBDD

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