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Thunder Power RC . Mikado Modellhubschrauber . GrandRC

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Flybarless Rotor Head Systems > New Flybarless System
 
 
flying glass
Heliman
Location: Rockford, IL. U.S.

For tuning the SK360 for multi-bladers, it seemed happiest with the phase trim about +5 to +10 degrees clockwise from the standard phasing from section 5 of the SK360 manual.

That is exactly what I found also.

I will look at increasing the depth of the slot in the head, hadn't thought of that.
Thanks for the advice.
John
04-15-2008 10:13 PM
 
 
lesodell3
Senior Heliman
Location: michigan usa

anyone have some pic of a trex500 head yet?

aah words to live by. "A side note, vigilante behaviour will be squelched!"
04-16-2008 01:26 AM
 
 
lesodell3
Senior Heliman
Location: michigan usa

anyone think a vbar head would work on a trex500
http://www.espritmodel.com/index.as...ROD&ProdID=6244



aah words to live by. "A side note, vigilante behaviour will be squelched!"
04-16-2008 02:06 AM
 
 
gorn
Elite Veteran
Location: Western Australia

Nope. The Vbar head is for the Trex600. For starters the width of the head will make your rotor diameter too large.
Too many what ifs.
Making a head flybarless is extremely easy. No nead to buy a new head.

If you bling it, they will come :D
04-16-2008 03:09 AM
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

> The Vbar head is for the Trex600

There are two Mikado V-Bar heads. One for the Logo 10/500 and one for the Logo 14/600. The blade bolt-to-blade bolt distance on the 500 size one is about 5 9/16".

- John

MSH Protos
04-16-2008 03:24 AM
 
 
FrittsLogic
Senior Heliman
Location: Honolulu, Hawaii

I just put my SK360 on my Trex 500. Hopefully I will get her airborne tomorrow. My gallery has pics of my approach. The swash driver is an extremely easy mod. I flipped my grips, and just for fun I will start with the stock Trex blade grip balls. I'm toying with a little theory that delta will not have as noticeable an effect on flybarless helis, where the gyros should be in firmer control of head response than a mechanical flybar. We'll see. If there's little difference, I'll flip the grips back to lagging control to see if that behaves differently. I did bring servo arm balls in one hole and pitch and cyclic range seem just about right. I'm using Futaba 9650's on the swash. I decided to move my tail gyro up front under the battery tray; I want to have easy access to the bell/hiller adjustments and so it gets to sit where the tail gyro used to. So to summarize, the only thing I used so far for the head mod that wasn't part of the stock Trex was longer link rods to go from swash to blade grips.

Menehune Rotorworks Inc.
04-16-2008 05:20 AM
HOMEPAGE  
 
 
tony_tuong
Senior Heliman
Location: northridge ca,91324

FrittsLogic
Please keep us posted.

Thanks
04-16-2008 04:13 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

I installed the sk360 in my T-rex 450 today, being a VBar veteran, I got it going fairly easy.

Took it out for a spin, hovered it, went perfectly, but I had some tail issues, landed, fixed the tail, took off, hovered it 10 seconds then WAM, it went full elevator back by it self.

Seems to work fine after a reboot.

Think I will sit back on this for a while, I dont trust it much right now.
04-16-2008 06:33 PM
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

MrMel,
Ouch! Sorry to hear that! I hope the real cause can be nailed down.

All,
I noticed that only one positive and ground connection is plugged into the receiver. That means all three swash servos are supplied through those single wires. I would think this could be a bad thing given some of the servos in use now and the current demands they bring with them. It would also cause the SK360 to see larger than necessary voltage dips. Thoughts?

I would be tempted to add another jumper between the rx and the extra output on the SK360 (just the positive and ground wires) or even directly from the battery or regulator.

- John

MSH Protos
04-16-2008 07:01 PM
 
 
Eury
rrProfessor
Location: Ankeny, IA, USA.

That's troubling, I guess mine will sit in the box for a while until the cause of that problem is found. Please keep us updated as you troubleshoot.


Nick Crego
Still wanted by the government, I survive as a soldier of fortune.
04-16-2008 07:35 PM
 
 
FrittsLogic
Senior Heliman
Location: Honolulu, Hawaii

Well, I just got back from the maiden flight on my Trex 500 SK360 project. Unfortunately, it did not go so well. It spooled up fine after passing the preflight checks but when I fed it positive collective to take off, it rolled right into the ground before getting airborne. Damage: main blades, tail blades, main gear, and two sets of 9650 gears. I was very meticulous in the setup: all setup and preflight checks passed with flying colors. Perhaps we need to "pop" it off the ground quickly to get sufficient altitude to give us a chance...

Menehune Rotorworks Inc.
04-16-2008 07:41 PM
HOMEPAGE  
 
 
Eury
rrProfessor
Location: Ankeny, IA, USA.

Hopefully we get someone from the company in here to talk about these results. JKos's findings on the power bus pretty much eliminate the ability to use the unit in a 50 or larger heli with high draw servos, and the 2 reports from end users who've flown it have both resulted in crashes within seconds of takeoff.

I'm wondering if the 5 second lockout that was mentioned earlier in the thread isn't a cause for Frittslogic's crash, and who knows on MrMel's. Either one could have another cause besides the SK360, but they could just as easily be blamed on the new system. I was planning on testing it in my 600N, if I decide to test it at all, maybe I should convert a Blade 400.


Nick Crego
Still wanted by the government, I survive as a soldier of fortune.
04-16-2008 08:39 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

In my case, nothing obvious on the heli, it has passed all checks afterwards, including a load test on the BEC.

Damage was pretty ok, main grips + tailfin.

working with skookumrobotics to see if we can nail it down.
04-16-2008 08:41 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

Quote 
I'm wondering if the 5 second lockout that was mentioned earlier in the thread isn't a cause for Frittslogic's crash, and who knows on MrMel's.

Mine was hovering good (could leave it hands off kind of good), I hovered for 10-15 seconds before it happened.

After resetting (battery in/out) everything works again.
04-16-2008 08:47 PM
 
 
Eury
rrProfessor
Location: Ankeny, IA, USA.

So when you got to the crash site, it was stuck with the controls locked in one direction, and when you cycled the power it came back to life?


Nick Crego
Still wanted by the government, I survive as a soldier of fortune.
04-16-2008 08:52 PM
 
 
Bruce2.5D
Heliman
Location: Vancouver, Canada

Hi All,

As MrMel stated we're working on finding a cause for his heli's issue right now.

Frittslogic's problem honestly sounds like a setup issue, but I'll get in contact to find out for sure.

Regarding the power bus issue, the voltage drop in the 8" cable at 4 amps total load should only be about 0.15v. If this is insufficient, connect the BEC directly to the 4th, unused output of the SK360. That way, only the tail servo and receiver would be powered through the cable.
04-16-2008 09:01 PM
 
 
LouInSD
Veteran
Location: San Diego CA USA

FrittsLogic,

I've read that the V-bar guys are seeing that issue with giving input while it is sitting on the ground.

Did it get off the ground before you gave it input?
04-16-2008 09:04 PM
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

Bruce,
I don't mean to make more of it then necessary. But, many of us have worked to make our power delivery system more robust such as multiple connections between regulator and receiver bus or even direct battery connection to the receiver bus in order to meet the demands of the newer super-fast, high-torque servos that are very common now even in 50-size helis. To go "backwards" to a single connection and wire just doesn't make sense.

Thanks,
John

MSH Protos
04-16-2008 09:15 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

Quote 
So when you got to the crash site, it was stuck with the controls locked in one direction, and when you cycled the power it came back to life?

Unfortunally, dont know, old habits die hard, I pulled the battery before testing/looking.

but it wasnt a receiver/control lockout, I had control via the throttle hold.
04-16-2008 09:16 PM
 
 
FrittsLogic
Senior Heliman
Location: Honolulu, Hawaii

Mine rolled over as I was lifting off. I did feed a litle cyclic in on liftoff for wind correction. I believed I had waited out the spool up initialization. I spooled up at zero pitch, waited for the esc to finish the slow start, waited some more. watched the wind bob the disc a little, waited a second or two more, then tried the liftoff. I triple checked my setup during install, and again just prior to spool up. Nose down made swash pull back, rolled right made swash go left. Tail checked fine. Solid green light was observed before starting spool up. I've never seen anything like this with my two Vbar'd helis.

Menehune Rotorworks Inc.
04-16-2008 09:22 PM
HOMEPAGE  
 
 
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