FlooredCOBRA

I just acquired a used Blade cp the other dayin a trade. When the guy I got it from started it up I noticed the main shaft was bent. I checked over the chopper and it looked fine except this. I went ahead and ordered a new shaft to replace it.

When I got home I wanted to try it out just to see what it would do. It spins up and right before lift off it starts to shudder and never gets off the ground. Is this due to the main shaft being bent? Also I find that it needs a lot of right to keep from rotating around. The tail rotor actually has to stop turning some times to keep it from rotating. Is that caused by the main shaft also or is there something else wrong?

I fly a Raptor for many years but something this small and electric is totally new to me. Any suggestions would be great. Thanks!

fire@forthall

Yes it sounds like the shaft is the cause of your "shutter". I think you will find that when you replace it it should run fine. you will see alot of people here straighten them and run them some more. I personaly would not do this. Just spend the money, they are cheap and you will find that the learning curve is alot better!

wilburwreckage

See how it is with the new shaft.

I would check for missing teeth on the servos. I have found it easy to miss this on quick inspection, but the gears tend to strip if you have hit it hard enough to bend the shaft. You don't necesarily notice it until your pitch and/or cyclic are in specific positions, and this will cause erratic behaviour. This is sometimes made worse because under no load the servos can seem fine.

I have got thru quite a few in my learning process. The annoying thing is you plant the thing, check it over, all looks good. Then fly it again. Hit a stripped spot on the servo and stack it again

I have been really dilligent recently on this front, and therefore have quite a few dud servos in a box However I recently bought some HS55's for my 400 size and made a discovery. The good news is HS55 servo gears fit the esky servos (I am pretty sure the blade ones are identical), and you can buy sets of replacements for a lot less than new servos.

Si

FlooredCOBRA

I hope the servo gears are not stripped. But I will look them over to see. The servos are Hitec HS55. You are saying that you have some in a 400. Is that a larger chopper? If it is maybe my servos are to big and heavy for the machine.
Like I said before I haven't a clue on anything this small. All new to me but hope to learn it and get the hang of it soon.

IMAC781

My Feedback: (2)

Here are the gear sets I've been using in my E-Flite S75s. http://www.horizonhobby.com/Products...rodID=EFLRS751
If you have a #0 Japanese size philips head screwdriver (one comes with the CP) it's not a difficult repair.

wilburwreckage

TBH the HS55's are probably too small for the larger heli.

The reason I suggested the HS55 gears is I found they were cheaper than the eflite ones ! I paid $1.20 (equivalent and I'm in the UK where all this stuff is more expensive anyway) I think they are probably higher quality as well, though this is subjective.


Si

FlooredCOBRA

I will keep that in mind. As it looks now my servos look good. But I am sure that I will have a mishap and will have to replaces the gears.

I am hoping that the new shaft will eliminate the tendency to try to rotate. I really dont like the idea of the tail rotor being fixed pitch. But the way it looks is all are like that in that size.

OttoNP

A bent spindle will cause weird wobble as well if your main shaft doesn't solve your problem. Also, be careful when you remove the main shaft, it will likely stick on the swash plate and bearings. You may need to sand or file near the pin to get it to slide our easily. Be especially careful when pulling it our of the swash plate, a friend of mine was pulling his through and would up breaking all three servos, if it doesn't slide out easy, you may want to disconnet swash plate from servos to avoid this.

RBCCONT

I have never been able to remove the main shaft without sanding the area around the sheer pin,the way i do it I remove the head,unplug the tail motor,and hold a 1/2 inch strip of sandpaper wraped around the shaft at the sheer pin spot and run the heli at half speed for a few min,after that she slips right out like butta..
just my 2 cents anyway

Pilot352

I just grab a pair of pliers and hold them over the pin hole. Then I twist the shaft. This smooths the area just fine. I then move the holding position above and below ane pin hole area and give a few more twists to remove any burrs caused by the pliers. It works greats.

-Pilot

FlooredCOBRA

Okay well heres is whats going on now. I picked my main shaft in from hobby shop today. I installed it and long with new gears fro my front servo. I found that it was stripped.

After I got my blades tracking correctly I took it outside to test it out. I advanced the throttle and the blades spooled up nicely. I found I was at pretty much full throttle and the chopper still sat there. Then all of a sudden I could see the blades get fat looking with pitch. At that second the chopper took off very fast straight up. I back off the throttle to get into a hover. I found that it had no effect as it came back to the ground.

If I hold the chopper in my hand and look from the side I can see whats going on. But I have no clue why its doing this. As I give throttle to almost full throttle i see the blades are flat. The out of nowhere they get max pitch and it has vertical pull as it should and tries to fly out of my hand. As I slowly back off the throttle the blades go from max pitch down to hardly nothing. Then I run the throttle back up the blades remain flat ad a few seconds later I get maxed out pitch. Trying to fly like this is impossible since I need immediate pitch to keep from hitting the ground. I cant wait for it to kick in a few seconds later. If I let it sit there for a second it gets pitch all of a sudden and tries to lift off again. For some reason I am getting slop or something thats causing this to act this way I think. I looked it all over but cant see why its doing this.

This is totally different from my Raptor I had. I never had that kind of problem but I did know how to work on it and trouble shoot when needed. This is a totally different machine all together. I am lost. I hope this made sense what i put above. If anyone can help let me know.

Thanks

FlooredCOBRA

Is it possible the servos are bad? This is the only thing I can think of thats allowing the sudden movement in pitch.

FlooredCOBRA

OKay I am out of ideas. I guess I will send it back and see if they can get it going correctly. I give up

wilburwreckage

Sounds like sticky collective problem!

Mine did this when it was new, and I had to dismantle it and swaps some washers round

My advice would be to take off the motor leads, then bench test that as you move the throttle/pitch stick up and down the pitch on the blades moves nice and smoothly.

Si