Swash mix question

benzee1 · 08-14-2009, 11:12 AM

My swash is set at 60%. Got +/- 10 on pitch. I want to set it to 12 deg. I increased swash to 70% and pitch didn't change. So I set swash mixes to 100%, still have + 10 deg pitch. Now, I see my servos increase their throw, but my pitch doesn't change. If I drop swash to 40%, then my pitch decreases. Why wouldn't my pitch increase when I increase swash mix, even though I can see the servos increase their throw?

I'm confused.

JoelKatz · 08-14-2009, 11:19 AM

Check the geometry of the servo horns to the linkages.

When the servo is centered and the horn is at 90 degrees, swash rotation turns perfectly into linkage movement. As the angle increases or decreases, it takes more and more swash rotation to produce the same amount of linkage movement. Once the angle gets close to 0 or 180, rotating the horn just moves the linkage forward or backward, not up or down.

The solution is probably to increase the servo horn length, usually by moving the linkage ball to a hole further from the center.

life2short1971 · 08-14-2009, 11:20 AM

Sevo arm center to ball center you need 12-13mm to get 12degree pitch.

benzee1 · 08-14-2009, 11:22 AM

Yes, I set all three so they are kept equal.

life2short1971 · 08-14-2009, 11:25 AM

Boy your fast.LOL I changed previous post assuming you had.

benzee1 · 08-14-2009, 11:28 AM

Joel, what you said makes sense. I'll check it out and see if the swash moves any higher or not when the servos throw more. If not, I'll replace the arms and extend the links out.

Bob O · 08-14-2009, 06:34 PM

I know this sounds stupid but I've read of stranger things happening with the DX-7. Try rebinding with the new swash mix value and see if that helps.

But if you see increased travel in the servo arms, that should translate into increased pitch, unless your swash is hitting the head block and binding.

Wierd.

benzee1 · 08-14-2009, 06:41 PM

I noticed that when I increase the elevator to 100%, the servo cage moves but the arms barely move at all. So yes, I need to move balls out on servo arms.

On side note, I increased pinion to a 13t (was 11t) and it handles the wind a lot better. But I had a booom strike.....see other thread.

08-14-2009, 11:12 AM	#1
benzee1 Registered Users My HF Map location Join Date: Jun 2008 Location: Corona, CA	Swash mix question My swash is set at 60%. Got +/- 10 on pitch. I want to set it to 12 deg. I increased swash to 70% and pitch didn't change. So I set swash mixes to 100%, still have + 10 deg pitch. Now, I see my servos increase their throw, but my pitch doesn't change. If I drop swash to 40%, then my pitch decreases. Why wouldn't my pitch increase when I increase swash mix, even though I can see the servos increase their throw? I'm confused. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. HeliSimRC Spektrum DX7, DX6i TREX 450, Blade 400, Blade CX2 Myspace.com/heliwhore

08-14-2009, 11:19 AM	#2
JoelKatz Registered Users Join Date: Feb 2009 Location: Murphys, CA	Check the geometry of the servo horns to the linkages. When the servo is centered and the horn is at 90 degrees, swash rotation turns perfectly into linkage movement. As the angle increases or decreases, it takes more and more swash rotation to produce the same amount of linkage movement. Once the angle gets close to 0 or 180, rotating the horn just moves the linkage forward or backward, not up or down. The solution is probably to increase the servo horn length, usually by moving the linkage ball to a hole further from the center. __________________ -- AMA 603884

08-14-2009, 11:20 AM	#3
life2short1971 Registered Users Join Date: Jan 2009 Location: Fort White,Florida	Sevo arm center to ball center you need 12-13mm to get 12degree pitch. __________________ Scott Trex 500 / /3026-1600/CC Ice75 /3G /Ds510's/Torsion 430 fbl's Trex 450 pro/HK2221-8/ Ice 50 /HS-5065MG/325D's/Kbdd's Last edited by life2short1971; 08-14-2009 at 11:23 AM.. Reason: ..

08-14-2009, 11:22 AM	#4
benzee1 Registered Users Thread Starter My HF Map location Join Date: Jun 2008 Location: Corona, CA	Yes, I set all three so they are kept equal. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. HeliSimRC Spektrum DX7, DX6i TREX 450, Blade 400, Blade CX2 Myspace.com/heliwhore

08-14-2009, 11:25 AM	#5
life2short1971 Registered Users Join Date: Jan 2009 Location: Fort White,Florida	Boy your fast.LOL I changed previous post assuming you had. __________________ Scott Trex 500 / /3026-1600/CC Ice75 /3G /Ds510's/Torsion 430 fbl's Trex 450 pro/HK2221-8/ Ice 50 /HS-5065MG/325D's/Kbdd's

08-14-2009, 11:28 AM	#6
benzee1 Registered Users Thread Starter My HF Map location Join Date: Jun 2008 Location: Corona, CA	Joel, what you said makes sense. I'll check it out and see if the swash moves any higher or not when the servos throw more. If not, I'll replace the arms and extend the links out. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. HeliSimRC Spektrum DX7, DX6i TREX 450, Blade 400, Blade CX2 Myspace.com/heliwhore

08-14-2009, 06:34 PM	#7
Bob O HF Support My HF Map location Join Date: Dec 2008 Location: Negaunee, Michigan	I know this sounds stupid but I've read of stranger things happening with the DX-7. Try rebinding with the new swash mix value and see if that helps. But if you see increased travel in the servo arms, that should translate into increased pitch, unless your swash is hitting the head block and binding. Wierd. __________________ Warp 360 Spartan Vortex VX1

08-14-2009, 06:41 PM	#8
benzee1 Registered Users Thread Starter My HF Map location Join Date: Jun 2008 Location: Corona, CA	I noticed that when I increase the elevator to 100%, the servo cage moves but the arms barely move at all. So yes, I need to move balls out on servo arms. On side note, I increased pinion to a 13t (was 11t) and it handles the wind a lot better. But I had a booom strike.....see other thread. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. HeliSimRC Spektrum DX7, DX6i TREX 450, Blade 400, Blade CX2 Myspace.com/heliwhore

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