My brushless MCPx thinks it's a dolphin!

[branmuffin]

i read this thread a few weeks ago before i went brushless, today i got the dolphin and instantly remebered seeing this thread. It hovers fine, but in FFF it looks like a dolphin swimming but it dosent have the effect when doing loops or rolls really. I know my servo linkage is beat to crap so i will put on some new ones and see what happens. Thanks for updating with your fix

[Tasteles]

This looks like the place to post this, I was having this problem on a fresh build, HP06v2/120SR tail RRC prop. Everything new except for the 3n1 board, blades balanced. Everything running smoothe except for the dolphin effect. After reading through this thread, I noticed one post about the High Perf blades. I had a brand new set of orange HP blades on it, so I decided to try a set of KBDD blades to see what happens. Well guess what, that solved my problem. Now I'm wondering why the HP blades cause this?

[branmuffin]

Originally Posted by Tasteles

This looks like the place to post this, I was having this problem on a fresh build, HP06v2/120SR tail RRC prop. Everything new except for the 3n1 board, blades balanced. Everything running smoothe except for the dolphin effect. After reading through this thread, I noticed one post about the High Perf blades. I had a brand new set of orange HP blades on it, so I decided to try a set of KBDD blades to see what happens. Well guess what, that solved my problem. Now I'm wondering why the HP blades cause this?

That is interesting, i got ride of most the dolphin effect from changing out my elevator servor which had some play in it but i do still have a small dolphin effect but i only run the stock HP blades, i will have to try the KBDD blades adn see what happens. Has anyone check out and seen what happens with bullet blades?

[Nytflyer]

The bullets work pretty well too for me. Sometimes I might get a little porpoise action from time to time but know where near what I get from the HP blades. I would love to know what actually causes this to happen as well.

Love HP blades on a stock heli the KBDDs just drain it IMO but they are all I run on both of my brushless birds they work great

[Tasteles]

I don't know, the HP blades are a little stiffer and the KBDD blades give more. Also the KBDD blades are a little shorter. I only had the dolphin effect running higher head speeds. If I ran at 70% governed, it didn't do it. I haven't tried the bullet blades yet on this bird, may give it a shot tomorrow and see what it does. I did hold the heli in hand and give it a slight foward elevator and watched all the servos jump to a rearward movement monentarily which is what was causing the dolphin effect. So it wasn't just one servo, it was all of them. It just seems strange to me that with the KBDD blades it quit doing it. Kinda made me think it was vibration related when I saw it, but I had good balance on the blades and it felt smoothe in my hand.

[mattijs]

I too still have the same problem. Flies fine but has dolphin thing going on too in FFF.
I fly the kbdd blades without a bullet. I'm gonna trythe bullet blades later to see if they fix the problem.
Well...fix...if they do, they'll probably only be able to mask the underlaying problem. I suspect my swash is a little on the loose side.

[DoubleCH]

Bullet blades has the CG way forward. That means they have more frontal area behind CG and therefore a better self-centering effect and that's why they're good for FFF flights. Hi-Perf blades get a much stronger force to pull them away from zero pitch (i.e. when you add pos pitch, wind blows on the blade so that you get more pos pitch, and vice versa) so if you have any slops on the servo linkages, head linkages, feathering shaft, swash, etc., the 3-axis gyro runs into hysteresis and therefore the porpoising.

[Tasteles]

Originally Posted by DoubleCH

Bullet blades has the CG way forward. That means they have more frontal area behind CG and therefore a better self-centering effect and that's why they're good for FFF flights. Hi-Perf blades get a much stronger force to pull them away from zero pitch (i.e. when you add pos pitch, wind blows on the blade so that you get more pos pitch, and vice versa) so if you have any slops on the servo linkages, head linkages, feathering shaft, swash, etc., the 3-axis gyro runs into hysteresis and therefore the porpoising.

In understaning this, would the heavy 120sr tail motor be causing it because it throws the cog aftward? I shortened my tail boom as much as I could to keep it clear of the main blades but it's still a little tail heavy. I know my dual 6mm tail has a perfect cog on the HP05 and it flies fine. But the HP06v2 has the 120sr tail and is a little tail heavy and that's the one that I get this effect with. If that's the case, by converting to the C05T tail motor, it should eliminate that problem, right?

edit: I should add that I don't have any slop in my servo linkage, all servos are new and seem really tite. I do also have silicone o-rings installed.

[mattijs]

solved my dolphin mystery. While the bullet blades made the problem appear much less it turned out indeed to be my new swash which was loose. Put the old swash in again and the problem went almost completely away even on rear cg blades. Now i wonder how to make the bad swash as the old/good one is missing one of the four inner arms....so when it looses one more i wouldn't be able to use it anymore.

[Bee_random]

Just solve this one for my latest build. New metal swash and the rear ball had worked itself lose. Now loctited and grommet mod to all three not just the front two. Also spotted a lose screw on a side servo.

[DoubleCH]

Originally Posted by Tasteles

In understaning this, would the heavy 120sr tail motor be causing it because it throws the cog aftward? I shortened my tail boom as much as I could to keep it clear of the main blades but it's still a little tail heavy. I know my dual 6mm tail has a perfect cog on the HP05 and it flies fine. But the HP06v2 has the 120sr tail and is a little tail heavy and that's the one that I get this effect with. If that's the case, by converting to the C05T tail motor, it should eliminate that problem, right?

edit: I should add that I don't have any slop in my servo linkage, all servos are new and seem really tite. I do also have silicone o-rings installed.

I was talking about CG of the blades. But, tail heavy bird does create problem. This makes the tail servo works harder than the 2 front ones on altitude change. Any slop will be amplified. IMO, 120 tail should go with 550 battery which when positioned way forward will balance out CG.

[Tasteles]

I use the 550 battery only way I know to get the COG any further foward with the battery would be to pull the canopy off and stick it in from the front maybe. Not real sure how much more room there is in the front of that canopy. I'll give it a try when I go home in a few weeks. I'm going thru heli withdraws right now being away for work.

[mattijs]

Originally Posted by Tasteles

I use the 550 battery only way I know to get the COG any further foward with the battery would be to pull the canopy off and stick it in from the front maybe. Not real sure how much more room there is in the front of that canopy. I'll give it a try when I go home in a few weeks. I'm going thru heli withdraws right now being away for work.

Probably the cg might help...but imo there is an underlaying cause. On my heli it turned out to be a new swash which sadlly came with alot more play than the old one it replaced. Alot of people have been flying with aft cg because among other things the sr120 tail...and they are flying around without dolphin issues .

[mattijs]

Originally Posted by mattijs

Probably the cg might help...but imo there is an underlaying cause. On my heli it turned out to be a new swash which sadlly came with alot more play than the old one it replaced. Alot of people have been flying with aft cg because among other things the sr120 tail...and they are flying around without dolphin issues .

I just went out in between two rain sessions to test if indeed my dolphin problem would show itself again with an aft cg. I didnt at all push the 550 to the front but made it sit approximately under the main shaft. Didnt test were that would bring the CG but it is bad for sure. My mcpx didn't dolphin and even going fff into the wind which would have been the worse before with the bad swash didnt make it do it. My 2 cents :°)