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jvthert · 03-16-2009, 06:07 AM

Hey guys,

I've noticed that most of you have pretty high gains on your sk360 compared to mine. Especially my dampening gains need to be as low as 10-11% and my stability gains are also in the upper 30's.
Furthermore I notice that the stability I'm able to achieve, especially at the end of my lipo is less than satisfactory.

Now I can't put my finger on it exactly but maybe someone here has a clue?

My setup is:

CC80 ESC, Neu 1907/1.5Y motor with 16T pinion. Headspeed is between 2600 and 2800
Indirect linkage set-up, Helidirect dampeners (HDX extra stiff), Torsion main blades
Running a torque-tube, Radix blades and a Spartan gyro on the tail
S9650@6v on the head and JR8900@5.2V on the tail (using spektrum regulator)

The only things I can think of are my dampeners or perhaps vibration issues. Has anyone else tried different dampeners and the effect on the SK360?

Help anyone?

t2o · 03-16-2009, 08:39 AM

Is everything slop and flex free? Do you have stiff bushings?

jvthert · 03-16-2009, 01:06 PM

Bushings? Do you mean dampeners? These are supposed be even stiffer that Align 3D dampeners with the feathering shaft sleeve...

I don't have any slop in my linkages. But I'll doublecheck.

jvthert · 03-16-2009, 02:29 PM

Updated setup in my first post

Furthermore I did find slop in my swashplate

Not good, but it's just a little bit. I'll order the new updates swashplate from align as soon as it's available but I wonder if it's te root cause.

Skint Eastwood · 03-17-2009, 06:20 AM

I have found the best dampener setup is the Align black with the plastic support tube. I tried grey but felt it to be more unstable and i tried some orange 3d (cant remember the make) but these gave me head bobbying when diving

jvthert · 03-17-2009, 06:31 AM

Darn, I took those out when I converted my heli. Mostly due to the fact that the manual says that stiffer dampening should be beneficial

I was just thinking about trying those orange 3d ones (K&D Dream design or sg.) The same brand that makes good plastic blades in neon colors.

I have to disassemble the head anyway to swap my swashplate. Before it seperates in flight!

Skint Eastwood · 03-17-2009, 06:55 AM

Quote:

Originally Posted by jvthert

Darn, I took those out when I converted my heli. Mostly due to the fact that the manual says that stiffer dampening should be beneficial

I was just thinking about trying those orange 3d ones (K&D Dream design or sg.) The same brand that makes good plastic blades in neon colors.

I have to disassemble the head anyway to swap my swashplate. Before it seperates in flight!

Thats the name of the orange dampeners in my post above!

jvthert · 03-22-2009, 12:17 PM

Today the wind was horrible. About 4Bft with gust up to 5/6 Bft. So a great day to do some tweaking

.

First while examining my heli on the table I found that one of the bladegrip links had came a bit loose. It turned out to be about 80% of the play I had on the blades! So I redid both links with some red locktite to keep them in place. I did the same for the mixing arms but that made little difference. The last bit of play will hopefully be gone when I get my new swashplate.

Concerning the dampeners: I think stiffer dampeners allows for lower dampening gains. Nothing more nothing less. At first I did not touch them and kept fiddeling with the hiller gains to achieve stable flight. This forced me to lower them far below 50 (~40) to get rid of the wobble in FF and sacrifice a lot of holding power.
Last time I found out that lowering the dampening gain helped a lot but I did not increase the hiller gains. Now I've dialed them back to about 50% and the dampening gains to 10%. And viola: my heli was of course still blown away like a poor leaf but kept is attitude perfectly. And no more wobbles too!

Looks like I have some Align dampeners for sale next week. Haha!

perfeet · 03-22-2009, 02:18 PM

Quote:

Originally Posted by Skint Eastwood

Thats the name of the orange dampeners in my post above!

I have orange K&B and my heli flies like on rails in SDFFF (Super Duper Fast Forward Flight)

Seriously I do dives from 100 feet and max out the speed on the horizontal flight. I love high speed.

No problems with stability with my Align head and K&B dampeners...

It is hard with helis. What works for one person does not always work for others.

PS: Try Oldschools profile and see if you like it...

jvthert · 03-22-2009, 05:15 PM

Flying with the wind gave me speeds exceeding 100km/h today, easily. Gusts were upto 60 km/h so go figure how fast I could fly today

I'll try Oldschools profile. See how that goes!

RobertAbles · 03-24-2009, 07:57 AM

My T500 FBL clocked in at 76 mph this weekend. I couldn't believe it..

They are fast!

Skookum · 03-27-2009, 09:26 PM

When you use harder head dampers there will be more vibration, that could be limiting how high you can get the SK360's gains. The "damping gain" is the one most sensitive to vibration as well. But it's also possible that with firmer head dampers, it doesn't need the gain to be quite so high.

BTW, I wouldn't put the damping gain on elevator below 10%, you can get nose up or down jumps in fast forward flight.

jvthert · 03-29-2009, 07:24 AM

Thanks Art!

I read your message after my test flight yesterday and I think you where totally right. Still a very mild wag on the elevator in FF. I'll lower D.gain to 9 on elevator and try again. Also the bell gains need to be a little lower. I could however up my hiller gains to about 54 and it's completely stable.

So speaking in percentages the dampening gains need to drop a lot and the bell gain a bit. Hiller gains can go up a bit and your heli is perfectly stable again!

03-22-2009, 12:17 PM	#8 (permalink)
jvthert Registered Users Thread Starter My HF Map location Join Date: Mar 2007	Stiffer dampeners = lower dampening gains Today the wind was horrible. About 4Bft with gust up to 5/6 Bft. So a great day to do some tweaking . First while examining my heli on the table I found that one of the bladegrip links had came a bit loose. It turned out to be about 80% of the play I had on the blades! So I redid both links with some red locktite to keep them in place. I did the same for the mixing arms but that made little difference. The last bit of play will hopefully be gone when I get my new swashplate. Concerning the dampeners: I think stiffer dampeners allows for lower dampening gains. Nothing more nothing less. At first I did not touch them and kept fiddeling with the hiller gains to achieve stable flight. This forced me to lower them far below 50 (~40) to get rid of the wobble in FF and sacrifice a lot of holding power. Last time I found out that lowering the dampening gain helped a lot but I did not increase the hiller gains. Now I've dialed them back to about 50% and the dampening gains to 10%. And viola: my heli was of course still blown away like a poor leaf but kept is attitude perfectly. And no more wobbles too! Looks like I have some Align dampeners for sale next week. Haha!

03-24-2009, 07:57 AM	#11 (permalink)
RobertAbles Registered Users Join Date: Nov 2006	My T500 FBL clocked in at 76 mph this weekend. I couldn't believe it.. They are fast! __________________ Robert Ables Gaui USA Team Pilot / Cyclone Blades Scorpion Power Systems / MKS USA / Optipower / VP Racing Fuels / YS Engines

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03-16-2009, 08:39 AM	#2 (permalink)
t2o Registered Users Join Date: Apr 2008	Is everything slop and flex free? Do you have stiff bushings?

03-16-2009, 01:06 PM	#3 (permalink)
jvthert Registered Users Thread Starter My HF Map location Join Date: Mar 2007	Bushings? Do you mean dampeners? These are supposed be even stiffer that Align 3D dampeners with the feathering shaft sleeve... I don't have any slop in my linkages. But I'll doublecheck.

03-16-2009, 02:29 PM	#4 (permalink)
jvthert Registered Users Thread Starter My HF Map location Join Date: Mar 2007	Updated setup in my first post Furthermore I did find slop in my swashplate Not good, but it's just a little bit. I'll order the new updates swashplate from align as soon as it's available but I wonder if it's te root cause.

03-17-2009, 06:20 AM	#5 (permalink)
Skint Eastwood Join Date: Apr 2008	I have found the best dampener setup is the Align black with the plastic support tube. I tried grey but felt it to be more unstable and i tried some orange 3d (cant remember the make) but these gave me head bobbying when diving

03-17-2009, 06:31 AM	#6 (permalink)
jvthert Registered Users Thread Starter My HF Map location Join Date: Mar 2007	Darn, I took those out when I converted my heli. Mostly due to the fact that the manual says that stiffer dampening should be beneficial I was just thinking about trying those orange 3d ones (K&D Dream design or sg.) The same brand that makes good plastic blades in neon colors. I have to disassemble the head anyway to swap my swashplate. Before it seperates in flight!

03-22-2009, 05:15 PM	#10 (permalink)
jvthert Registered Users Thread Starter My HF Map location Join Date: Mar 2007	Flying with the wind gave me speeds exceeding 100km/h today, easily. Gusts were upto 60 km/h so go figure how fast I could fly today I'll try Oldschools profile. See how that goes!

03-27-2009, 09:26 PM	#12 (permalink)
Skookum Registered Users Join Date: Jan 2008	When you use harder head dampers there will be more vibration, that could be limiting how high you can get the SK360's gains. The "damping gain" is the one most sensitive to vibration as well. But it's also possible that with firmer head dampers, it doesn't need the gain to be quite so high. BTW, I wouldn't put the damping gain on elevator below 10%, you can get nose up or down jumps in fast forward flight.

03-29-2009, 07:24 AM	#13 (permalink)
jvthert Registered Users Thread Starter My HF Map location Join Date: Mar 2007	Thanks Art! I read your message after my test flight yesterday and I think you where totally right. Still a very mild wag on the elevator in FF. I'll lower D.gain to 9 on elevator and try again. Also the bell gains need to be a little lower. I could however up my hiller gains to about 54 and it's completely stable. So speaking in percentages the dampening gains need to drop a lot and the bell gain a bit. Hiller gains can go up a bit and your heli is perfectly stable again!

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