White 3D paddles pitch down in very fast FF

[ImRich]

I have a set of the White 3D paddles on a couple of my ships now.

One is my Gas X-Cell the other is my R50V2.

I find that in very fast forward flight they start start to pitch down and get very sensitive.

When I'm doing a fast 'fly by', as I pick up speed, the heli starts to pitch down. It doesn't do this with less agressive paddles.

Is there something I should check or adjust to get rid of this tendancy to pitch down?

I have my C/G set correct. I'm running about -40% expo on my Futaba. I've sanded off the mold lines all around the paddles.

Any ideas? I love these paddles for their responsiveness, but don't like the pitching down at fast forward speeds so I'm torn between leaving them on or taking them off.

[ChrisS]

Most likely you don't have enough headspeed. Light paddles, any light paddles will get more sensitive the faster the heli moves. Just try turning your headspeed up a 100 rpm or so and see if things don't change for the better.

Chris

[ImRich]

Hi Chris,

I was running 1700 or even 1800 head speed. Wouldn't this be enough? :D

This pitchyness doesn't happen at usual forward flying speed, but if I I dive for a lot of speed, have a lot of collective (not full collective, but close) and level out and try to fly a fast pass I find the heli seems to dive toward the ground as if I have my trim set wrong.

I usually trim for hover not for forward flight. I would expect a climb in this condition as translational lift should be greater. I certainly don't have any negative pitch involved. ;) I was thinking that perhaps some mixing ratio has to change, but I'm not sure what? Forward cyclic for forward flight + positive collective for speed seems to cause the pitch down. This didn't happen with less aggressive paddles.

Does this make sense?

Could a few hundred more rotor RPM make this effect go away?

[WillJames]

Shannon always runs up and sands the mould lines off the ones I run. He hits all the sharp edges with the sandpaper to. Afterward it was a lot less pitchy in FFF on R60-90.

[ImRich]

Thanks Will,

I do that as a matter of fact thing for all plastic parts, I don't like mold lines! They makes my equipment look moldy (ok, my poor humor).

There are no mold lines on this set of paddles.

I guess I should say this is not just a pitchyness issue. It's a tendancy to pitch down in extremely fast forward flight. Of course these paddles are much more responsive, so I expect them to be more 'alive' when I put in cyclic, but I'm surprized by the pitch down in fast forward flight and am trying to understand why it does this.

I've noticed this the most on my R50V2. I'll have to run my Gas X-Cell again to see if it does it too.

[GM1]

You can either change horizontal fin area, lengthen the flybar, or thicken the paddles to increase drag on the head to decrease this pitch down tendency.
Gordie

[ImRich]

I would think the easiest thing would be to increase the horizontal fin area. I'll have to experiment with that. Has anyone else seen this effect. I can't imagine I'm the only one.

[rcheliflyer]

White MA paddles:
I had that pitchyness on my Rap also, I solved it by installing
CF paddles that are similar to the V-Paddles with Flybar wts for tuning.
Flys better on windy days with great cyclic response.

[Sar]

This may or may not help you. The elevator control linkage from the servo to the first lever(mounted to the side of the pitch control arm) is a long rod in the Raptors. I glued a CF tube over this rod to keep it from flexing under heavy load and that eliminated a lot of the pitch down tendancy in FFF on my R60. I run the white MA paddles on it as well.

[WillJames]

What main blades are you running. I have the exact problem with my R90's. I run MAH DT G2 700 and 710mm mains and the V2 paddles or whithe MA paddles and my machines do this. Clintstone got me to try a set of some V mains he had last weekend and believe it or not the pitch down was gone with only a main blade change!!

That pitch down is a little unnerving to me to Rich. Seems like when you add the necessary elevator to counteract the pitch down it bleeds off a bunch of your speed. :(

[bigrcr]

With the light paddles as you go into "extremely fast" forward flight, the flight speed outruns the head speed and the flybar looses it's authority.

.

[pdman]

I had the same problem with my raptor 60. Problem is that the airfoil of the MA 3D paddles does not work well with the raptor's cyclic mixing ratio as it does with the Fury's mixing.... change the paddles to ones that have a better airfoil like the V-Paddles.... solves the problem right away... you will still get similar response as the MA 3d paddles.

[ImRich]

I found the root problem for my pitchyness on my R50V2.

I discussed it here:
http://www.helifreak.com/viewtopic.php?t=1766

By the way, someone told me that MinAir is discontinuing the 3mm white 3D paddles :(