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billyd
02-19-2008, 10:54 AM
Great job gra55hopper!!!! Very stable.

What are your settings for yaw compensation? Did you do it in the TH2 or the Tx?

Thanks for posting the video, it's going to force me to paint my canopy, I am still flying the "visible human" version :YeaBaby:
Gra55h0pper
02-20-2008, 03:56 AM
Great job gra55hopper!!!! Very stable.

What are your settings for yaw compensation? Did you do it in the TH2 or the Tx?


Thanks Billy!
I programmed the yaw compensation in the TH2. My theory is that this way the TH2 sees any inputs given by the DCP gyro which induce yaw. The only thing is I'm not sure how much I ended up with and with the fuse on it's a little tough to check now... :D
Gra55h0pper
02-20-2008, 04:06 AM
What do you have stabilizing the DCP ? Looked like some FRVI during FF to hover.

I have a 240 in HH mode (at 50% gain) on the DCP. The DCP channel is generated (on the heli itself in my case) at ~60% of the elevator channel.

You're right in that there is some FRVI. I don't think I had that when I flew without the body (I spent quite a bit of time on the setup) so I'm wondering whether perhaps the body makes the heli a little more sensitive to it. Perhaps it's the additional weight (the painted fuse is not light and weighs about as much as my 4S 2170 mAh LIPO) or perhaps it's related to the body "messing" with the rotor vortexes (I would expect the lift in the center to be a little less due to the fuse "being in the way" but I'm not sure exactly whether that would explain it).
Anyway, it doesn't really bother me at this point and I'll leave things as they are for now.
MadDogDan
02-20-2008, 08:37 AM
For us novices what is FRVI?

MadDog
tungym
02-20-2008, 09:41 AM
Drop of tail due to the rear rotor entered into the downtrust/Vortex of the front rotor. Front Rotor Vortex Interference. right?
billyd
02-20-2008, 01:45 PM
Thanks Billy!
I programmed the yaw compensation in the TH2. My theory is that this way the TH2 sees any inputs given by the DCP gyro which induce yaw. The only thing is I'm not sure how much I ended up with and with the fuse on it's a little tough to check now... :D


Understood, but I'd love to hear the process. I don't even know where to begin.
sokal
02-21-2008, 10:14 PM
hey HOPPER that was great very real looking
all u need now is a sling load
Gra55h0pper
02-22-2008, 03:06 AM
Understood, but I'd love to hear the process. I don't even know where to begin.

Please see the TH-2 support page on http://www.tech-mp.com/tandem_sw.htm. It's explained here how to program the TH-2 through a USB link with your computer. Assuming you've got that working, then there is a program setting called "Yaw compensation". What it does is inside the TH-2 mix DCP into yaw, i.e. when the TH-2 sees an input on the DCP it will not only output the DCP to the swatchplates but also a bit of yaw in order to counter the yaw effect which the DCP input induces.

Hope this helps -- H0pper.
sokal
02-23-2008, 04:36 PM
the 47 swashplate has a 45 deg from center position
wonder if thats any thoughts on mechanics of the swash
may be they could intergrate the LCT function with the elev servo
good2win22
02-23-2008, 08:50 PM
Actually, the 47 swashplate is phased 38.5 degrees off of the center position. The pitch arm on the pitch varying housing takes up the rest.


This is a fun topic with a new WOJG. It usually takes them a good while to fully understand the positioning of the fixed links/LCT's on both the forward and aft rotors.

Gotta love phase lag....
chinookmark
02-23-2008, 09:26 PM
Gotta love phase lag....

That's one of those things that I will just never comprehend ..... like women.
sokal
02-25-2008, 03:24 AM
man need to get back in to the books
i took a guess
wont make FE like that
well still if the mixer could incorperate the LCT that would be interestng
good2win22
02-25-2008, 06:44 AM
The LCT's are there to help compensate for dyssemitry of lift. Because of differential collective pitch the 47 does not fully cyclic feather the rotor system in the longitudinal axis. The LCT's help with that as well as give the 47 the level hover attitude because of the angle at which the forward and aft transmissions are installed and assist with ground taxiing.
chinookmark
02-25-2008, 06:23 PM
well still if the mixer could incorperate the LCT that would be interestng

It sort of does. The Twinn Rexx just uses it different than the full scale 'hook. The elevator channel in the TH-2 controls the swashplate similar to the LCT's, except that we control the elevator, and the 'hook uses LCT's depending on airspeed.