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Flybarless Rotor Head Systems > New Flybarless System
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

Yes, that'd have the same effect. If your takeoffs are smooth now, there's no harm in lowering hiller decay to 50% though too.
05-11-2008 10:39 AM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

Quote 
will trimming the links to correct drift be the same as trimming on your radio, back to zero again? after a reboot?

No, can only speak for VBar but thats how you get rid of drifting on that one (or correct in the program)
05-11-2008 10:40 AM
 
 
e-copter
Senior Heliman
Location: Nice, France

Hi,

more testing this morning, so far, so good ))

I'm now making a new swashplate follower (as on my micro 300 fbl head on pic below) and reinforced linkages for the Bell 222.

I will then mill a quad blade rotor hub for fitting in the Bell 429 (unpainted fuse on the pic) and hope to get as good performances as on the 222. If working fine then i'll try the elevated mount on the EC 145 ( not on the pics as i'm waiting for the license from Eurocopter in the next few days so i can't show it yet).

I plan then to mount the unit in a 300 size mechanics Hugues 500 with 5 blades ( i'll use Ms composit blades of the AS 350 Squirrel) and if it works, i'll go for the micro EC 155 but it will be a big challeng for me to fly with the 5 blades + Sk 360 + micro fenestron as it is a very sensitive mechanics especially on the tail fenestron lol !!

I did not use auto trims, i simply did the SK 360 recognise my transmitter setup, then went to fly without the SK 360 plugged, srtup the trims on teh transmitter, and then made a new setup with letting the SK 360 reading my new values (trims included).

I'm very happy with the results and the software is much easier to handle than the Vbar software on my on point of view.

I'll try to make a little video end of next week as children / house / work do not let me a lot of time to go to the flying field so all tests are made in the garden in " ninja mode" lol.

BEst regards,

Fabien




Too much is not enough....
05-11-2008 01:04 PM
 
 
RotorRage
Veteran
Location: Lake Charles, La.

That scale ship is going to be awesome!
I bet a kasama hub and grips would look cool without the flybar.

When life gets rough don't pick your nose or you might stab your brain!
05-13-2008 10:52 PM
 
 
chichisport
Heliman
Location: Tenerife,SPAIN

Hello

Yesterday I had received the new SK 360 ,as the previous was affected by the cold test but flying OK.
I changed to 10 degree cyclic , lowered the decay to 60 and try 270 degrees rates.

I must admit that i did not try tunning gains and are quite low on hiller 50 and 40 .

The hovering feeling is quite loose (must try higher hiller).

Elevator rate is super quick (too much),but aileron is not that much.Is there a phisical reason ???

The bad comes when two times I get hit by quick oscillations (ELEV KICKS).
Iīm going to lower rates to 210 degrees and try as high as I could hiller gains.
What should I do to get rid of the ocassional elevator Kicks? higher vibration filter? (currently 1).
All that is in a micro heli Maxir SE ,very tight controls.

[
05-15-2008 12:04 PM
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

>What should I do to get rid of the occasional elevator Kicks? higher vibration filter? (currently 1).

The vibration filter setting probably wouldn't help, it's mostly there to protect digital servos from responding to vibration too much.

After some testing here with a heli that had similar symptoms, the problem was traced to vibration from the tail rotor. It spins much faster than the main blades, and few people balance it. While a tail gyro isn't usually affected by tail vibes, a cyclic gyro is because the tail rotor's vibration is in the same plane as the elevator axis.

So there are two approaches. One is to balance your tail rotor, and the other will be the next firmware update. That update will:

* Handle high-freq vibes better
* Trim out the gentle backwards drift that people have noticed while hiller-decay is set high
* Allow advanced users to adjust the tail-drag comp value themselves
05-18-2008 07:46 PM
 
 
chichisport
Heliman
Location: Tenerife,SPAIN

Thatīs a nice explanation ,hope the patch came up soon.
05-18-2008 09:08 PM
 
 
e-copter
Senior Heliman
Location: Nice, France

Hi Chichisport,

i can see on your maxi r, that you use the Maxi R 4 plastic blades.

YOu will not get very good flight with the SK 360 with these blades.

I recomend you to change and use the carbon blades of the Maxi R SE, they will work much better.

These plastic blades are too soft and are for scale flight without gyro help at all. As they are very heavy as well, you get a lot of inertia ( i had a Maxi R 4 for a loong time) and the response time is too much deleyed compared to the inputs.

As well, the tail of the Maxi R needs a looooot of atteention with the torque tube in carbon inside to have minimum vibrations.

Most gyro issues are coming from tail vibratings as Art said and the maxi R tail is not easy to tweak for no vibrations, especialy at high revs.

The best thing is to use a metal tube for torque tube instead of the carbon tube, check it's perfect straight, and on the tail, you can use a Duzi tail mod or a Aplus 300 tail unit, they work great ( Hub / blade grips / pitch slider).

I'll put later int he evening a picture of a modified tail for the Maxi R which works reallly well and is easy to make ( based on Aplus 300 parts and the very first Aplus prototype tail pitch slider unit from Flying Hobby).

BEst regards,

Fabien

Too much is not enough....
05-18-2008 09:15 PM
 
 
gian
Senior Heliman
Location: AZ

Just bumping this for more information. How are we doing? Any more crashes/ success stories? Wanna' trade me for a 502?
05-23-2008 10:35 PM
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

Firmware Update #2

Hi All,

The second firmware update is up on the support page of the website, at:
http://www.skookumrobotics.com/support/

Changes include:
* You can now tune the tail drag compensation yourself
* Tail comp is applied in a slightly different way to eliminate the gentle back-drift seen with 100% hiller decay
* Further improvement in vibration resistance, espec from tail vibration.
* Suppressed the cyclic-stick-off-center-at-init alarm while in setup mode, because it was too annoying. It's still active in flight mode.

Maxing out vib resistance cost a reduction of the digital servo frame rate to 125 Hz (was 140), but this slight drop should cause zero performance loss for a cyclic gyro, because even at 3000rpm the blades only go around at 50Hz.
05-24-2008 12:45 AM
 
 
e-copter
Senior Heliman
Location: Nice, France

Cool !!!

testing tomorrow

I have one question for you Art

Depending on the blades i use ( i have micro Hugues 500 with 5 bladed head, and we test the rotor head for you as well) , there is some "latency" in the cyclic reactivity ( depending on the blade weight, and flex). When we modify the gain, foes this affect as well the delay or is there any function i can use to work on this ?

The unit works awesome actually, even with the very first firmware, and i'm testing different hubs width and delta settings on the Excellium 500 now. We made the rotor head to be convertible to flybarless with just changing the blade grips arms and a modified central part. This helps a lot in testing different stupid thigs
I spend half time to fly with the unit, half time to remove it and install it on everything i can

BEst regards,

Fabien

PS: here is the pic of the flybar version of the head, flybarless version is made with just changing central part, adding the swashplate follower and changing the blade grips arms



Too much is not enough....
05-24-2008 01:42 AM
 
 
renelu
Heliman
Location: Virginia Beach, VA, USA

I've played a little with the SK360 (bought it from a Mikado Vbar user who changed his mind). I've got the first firmware update and have had two crashes trying to set up my T-Rex 500. The first flight, prior to the update, before leaving the ground, there was a very sharp left cyclic deflection which tipped the heli over and stripped a cyclic servo gear and chewed up a main gear. The second flight was a bit better, and statically, I reduced the hiller decay way down to 30%, and was locked into a 5ft hover for about 30 sec. until there was a sharp forward cyclic deflection which I couldn't compensate for in time and did a lot more damage when that went in. I'll try the second firmware update after I get a test flight back in stock (flybar'ed) form.

Neil
05-24-2008 01:51 AM
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

Fabien> "Depending on the blades i use ...there is some "latency" in the cyclic reactivity ( depending on the blade weight, and flex). When we modify the gain, foes this affect as well the delay or is there any function i can use to work on this ?"

Nice rotor head! Modifying the Hiller gain will probably not affect the delay you are seeing. What would cause such delay is the Bell gain not being high enough. The ideal Bell gain will change if you go to heavier/lighter blades or a large difference in headspeed.

Neil: Spin the heli up gradually and be ready on the throttle hold switch, if its going to have a vibration-related tipping problem it will show at spool up first. It's a good idea also to check your tail rotor's balance. If you keep having problems even with rev 1.02 of the fw, then we will honor the warranty and replace the gyro even if you're not the original purchaser.
05-24-2008 03:12 AM
 
 
renelu
Heliman
Location: Virginia Beach, VA, USA

Thanks for the support! I'll be balancing the tail after I get the new torque tube kit - hopefully it will get here tomorrow. Perhaps a vibration problem is what I saw in the first crash, and it was masked by dropping the hiller decay to 30% in the second one?
05-24-2008 03:48 AM
 
 
chichisport
Heliman
Location: Tenerife,SPAIN

First thank to Bruce for solving my problem. 1.2 solve my problem of elev kicking back . Neil ,setup your heli to 2 widely different headspeeds , If you get a kick inmediately switch to the other one ,this is what was usefull to stop the kicking in flight.

Whay was strange in my maxir ,is that I got the tail as vibe free as possible, the tail fin doesnīt buzz at all. Iīm running a 3mm carbon tube with only the ends being 2mm ,pretty stiff. I wonder if the vibe is related to meshing of the tail pinions , If they make noise they had to be vibrating,??????
I tried the plastics and also some carbon blades I made that are at least twice stiff as LAheli carbons. Not too much of a difference in flight . I think the Sk360 can drive the blades so fast that the plastic donīt represent a limit to the system.

Now Iīm ready to switch the unit to the Laheli Sniper . Itīs a nice heli but a bit doggy ,I need faster cyclics ,well I want them.
05-24-2008 04:58 PM
 
 
Unpoor
Heliman
Location: Ange Sweden

tested again with new fw, same thing it still drifts, turned hiller gain down around 55, still drift but not that much, still doesnt loop straight.. comes out leaning to the left, why? drift to the right and comes out of a loop the other way..

T-Rex 600N Pro SK360, Hurricane 550, T-Rex Hybrid, DX7
05-25-2008 08:26 AM
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

Hi Unpoor

Re uneven loops / drift, I can't remember anymore what we've checked so far on yours, but here would be the normal suspects:

(1) Reducing hiller *Gain* will result in more drift, and it won't hold as well. However, reducing Hiller *Decay* will result in less drift at hover. If your takeoffs feel safe, try setting hiller decay down to 50% (for hard 3D you'll still want 100% though).

(2) Have you checked that in setup mode, the swash is level at both positive and negative collective pitch? To adjust this, change the individual servo travels in the gyro's setup software. Servos are not all identical; the pots that measure position can vary by 10% or more.

(3) The heli may also have some kind of aerodynamic asymmetry like tail drag effects (all helis do). The latest setup software allows you to tune the tail-drag compensation, which helps the gyro counteract that during fast control inputs. To tune the tail comp, *first* check (2) above.
Then hover the heli stationary, and quickly hit full positive pitch. Look to see if it tilts nose up or down, left or right. If it tilts nose up, you want to change tail drag comp for elevator to be lower (say -2). If it tilts right, adjust tail drag comp for aileron to be lower (and vice-versa if it tilts nose down or left).
05-25-2008 09:53 AM
 
 
chichisport
Heliman
Location: Tenerife,SPAIN

Then hover the heli stationary, and quickly hit full positive pitch. Look to see if it tilts nose up or down, left or right. If it tilts nose up, you want to change tail drag comp for elevator to be lower (say -2).

Does it make sense?

I think normal compensation is to nose down to compensate for noseup ,less compensation will be more noseup. Am I right?

Cheers.
05-25-2008 11:31 AM
 
 
lesodell3
Senior Heliman
Location: michigan usa

1.2 update is working good for me thanks for the hard work

aah words to live by. "A side note, vigilante behaviour will be squelched!"
05-25-2008 12:57 PM
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

>>"I think normal compensation is to nose down to compensate for noseup, less compensation will be more noseup. Am I right?"

The convention used is that a negative number will feed in nose-down elevator when you apply positive collective. The default tail comp for elevator is -6, so if it still noses-up at hard collective pitch, you want to try say -7.
05-25-2008 01:38 PM
 
 
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Flybarless Rotor Head Systems > New Flybarless System
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