Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopter Support > 250 Class Electric Helicopters


250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


Reply
 
LinkBack Thread Tools Display Modes
Old 07-10-2013, 05:38 PM   #241 (permalink)
Registered Users
 
Posts: 1,208
 

Join Date: Mar 2011
Default

my two cents:
noticed on the bench that when moving the tail slowly and evenly the gyro doesn't seem too notice ( gp750 and spartan760) and thus the tailservo doesn't move

so for one i'll do the rate mode setup tomorrow (at 100% throttle) as best i can with the biggest possible tailblade size, guess this also why high headspeed which gives the tailblades more speed and so generates more thrust of the tailblades and gyroscopic effect helps the tail to stay neutral in hoover?

then i noticed that on my medium sloppy setups the tailblades do not hardly move when the tailservo ball is on 4.5mm and one moves the tail around neutral, the servohorn movement doesnot generate tailblade movement untill after so many degrees into the tail moving off neutral, maybe that's why the mks ds95i works so well as it is very fast and one can thus raise the gain evenmore which makes the gyro correction even stronger without causing a tailwag

so then it's mixing tailblade size/servoball length against slow tailservo/gyro deathband/gyro gain

wonder if a boom extension kit might not solve a lot of the tail wag issues?

EDIT:
mixed results, one with a ds8910 flies ok but tail not that there yet, my basher with tgy306 on tail needs
flies also ok but get wag during flight so will go with smaller tail blades
overall the headspeed is pretty important as my packs are tired it varies a lot and so does the tail behaviour...

Last edited by apper001; 07-11-2013 at 02:24 PM..
apper001 is offline        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 09-13-2013, 11:05 PM   #242 (permalink)
Registered Users
 

Join Date: Dec 2011
Default Finally cured the Wag

Been reading some of the comments on wag for the informass Tail wag issues with heli. My cure was simple removed the tail hub put it in a dremel removed the Shoulder that the blade grips bind on with a file fine,and slipped on a inner bearing off an old MSR main shaft i had lying around and spaced the blade grips with a alloy cover washer used a longer bolt for the blade grips no more binding ran it up with no main blades on easy as then flew it ,where i was running 35% gyro turned it up too 75% perfect Hope it helps some one else as you comments helped me Cheers .
tunner777 is offline        Reply With Quote Quick reply to this message
Old 09-13-2013, 11:15 PM   #243 (permalink)
 
My HF Map location
Join Date: Sep 2011
Default

Lynx 42mm TR removed my wag, even with 100% gyro gain
BladeScraper is offline        Reply With Quote Quick reply to this message
Old 09-14-2013, 05:25 PM   #244 (permalink)
Registered Users
 

Join Date: May 2011
Default

Quote:
Originally Posted by tunner777 View Post
Been reading some of the comments on wag for the informass Tail wag issues with heli. My cure was simple removed the tail hub put it in a dremel removed the Shoulder that the blade grips bind on with a file fine,and slipped on a inner bearing off an old MSR main shaft i had lying around and spaced the blade grips with a alloy cover washer used a longer bolt for the blade grips no more binding ran it up with no main blades on easy as then flew it ,where i was running 35% gyro turned it up too 75% perfect Hope it helps some one else as you comments helped me Cheers .
Is it possible to show some pictures to clarify the modification ?
__________________
Nano CPx, Hirobo Quark
250 SE, Pro Upper Frame, Talon25, KDE, KST215, DS95i, Mini Vbar
450 Pro (6s), KDE, Lynx, Tarot, RJX, YEP40, KST215 & 515, SK540
465 (6s), Align DFC, HW50AV3, KST315 & 8910A+, SK720BE
lcc014 is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 08:11 AM   #245 (permalink)
Registered Users
 
Posts: 912
 

Join Date: Jul 2009
Default HK250 GT flies well

Yay! I balanced a troublesome HK250GT. I used spectral analysis (Audacity) to identify imbalances. see thread here: http://www.rcgroups.com/forums/showt...3#post26168424

Starting with the tail and running at half throttle I used Audacity to minimize the tail spike. Surprisingly the rotor head/flybar assembly needed a lot of balance weight. And then I spun it up with blades for the final tweaks. It came out smooth.

IT FLIES with no shakes. The tail holds well just like a good dbl bl mcpx. Now, if I can just speed up the slow handling. With TA at 150, DR at 125, expo at 0% and pitch curves maxed out, What else can I do to speed up the controls?

I now have two 250s to test fly along with my fleet of modded ultra micro Blades

I will try to put together screenshots and writing to document my efforts. I will do that later! It's getting light! And I gotta fly. There is a houseful of teenagers, too. I must come back with food or there will be trouble.

BTW, I have two small Chinese blade balancers for sale.
__________________
Good luck and happy landings.
daveapplemotors is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 11:41 AM   #246 (permalink)
Registered Users
 
Posts: 81
 

Join Date: Feb 2011
Default

Hey everyone again! I left the Trex sitting on a shelf for more than a year, really discouraged by the fact I couldn't solve the wag no matter what.
Last week I decided to upgrade my 450 to FBL and this allowed me to move the Spartan Quark I had on it to the 250. Needless to say the Quark was rock solid on the 450.
At the same time I changed the tail servo from the stock DS420 to a Turnigy S306G which is supposed to be a DS95i clone.
This morning, excited as never before, I went to the club and powered the 250 up. Guess what? Wag as before. I couldn't believe my eyes. I started lowering the gain, until I got to 4% real gain (I am using a DX8), but it only slowed down the wag.

So this is what I did, in the hope you see something dumb and help me out:
- changed the stock gp790 gyro for a spartan quark
- mounted the gyro with its metal plate between a thin foam layer and a thicker one
- changed the servo to a tgy s306G
- ball link is 4.5 mm from servo arm center (too close?)
- tail mechanism is pretty smooth, there is a tiny bit of slop but the 450 is the same and flew awesome
- vibes are not anyhing exceptional, the heli feels pretty smooth
- wags is slow at 4% gain HH, fast at 30% and crazy at 50%. It made for an interesting landing!

I am at a loss here, any idea?

Thanks heaps in advance!

Edit: I also changed the stock tail blades for KBDD 40mm.
__________________
Blade Nano cpX, fully stock - Blade 130x, bling galore - Rex 250 Pro converted to FBL, 3GX - DS95i - HK 450 PRO converted to DFC, ZYX - Futaba 9257 - Rex 550 DFC, Beast X
gionir is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 12:20 PM   #247 (permalink)
Registered Users
 
Posts: 2,970
 

Join Date: Jan 2011
Default

> I am at a loss here, any idea?
Not to be flippant, but have you read the preceding 245 posts? Tons of ideas there.
The same amount of slop as a 450 on a bird a fraction of the size can be a problem.
Moving the ball link closer to the center is thought to help, so that shouldn't be a problem.
And of course, there's the old troubleshooter's rule about only changing one thing at a time...
Good luck! (You may need it--the 250 is a really fun little bird when it's flying well, but if it's in the mood to shake its butt, call the exorcist...)
Harbormaster is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 12:36 PM   #248 (permalink)
Registered Users
 
Posts: 81
 

Join Date: Feb 2011
Default

Hi harbormaster,
Thanks for the reply, yes I have read the previous pages, still I am a repetitive offender of the wag crime
My mistake, what I meant with the slop thing is that there is some but I wouldn't say that it is out of control, a degree or two of deflection of the blades.
And you are very right, next thing is to go back to the stock servo and see what happens..

If anyone else has ideas...I'll be very happy to hear them!

Cheers
__________________
Blade Nano cpX, fully stock - Blade 130x, bling galore - Rex 250 Pro converted to FBL, 3GX - DS95i - HK 450 PRO converted to DFC, ZYX - Futaba 9257 - Rex 550 DFC, Beast X
gionir is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 01:42 PM   #249 (permalink)
Registered Users
 
Posts: 2,970
 

Join Date: Jan 2011
Default

Quote:
Originally Posted by gionir View Post
next thing is to go back to the stock servo and see what happens..
Going to the fastest tail servo around (a Ds95i) and Chinese weights pretty much did it for me (especially the servo--throwing lots of money at an intractable technical problem does sometimes make a difference! )
Harbormaster is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 07:04 PM   #250 (permalink)
Registered Users
 
Posts: 81
 

Join Date: Feb 2011
Default

haha I hear you, unfortunately I am not in the position to throw almost $100 in a servo...I'll have to try and solve this puzzle with what I have around..
But really what I cannot understand is why the tail wags even if the gain is as low as 4%, and still holds in pitch pumps. This sounds pretty wrong to me.
__________________
Blade Nano cpX, fully stock - Blade 130x, bling galore - Rex 250 Pro converted to FBL, 3GX - DS95i - HK 450 PRO converted to DFC, ZYX - Futaba 9257 - Rex 550 DFC, Beast X
gionir is offline        Reply With Quote Quick reply to this message
Old 09-21-2013, 08:31 PM   #251 (permalink)
Registered Users
 
Posts: 2,970
 

Join Date: Jan 2011
Default

Quote:
Originally Posted by gionir View Post
what I cannot understand is why the tail wags even if the gain is as low as 4%, and still holds in pitch pumps. This sounds pretty wrong to me.
My aeronautical engineer flying partner can go on at length about how that's all explained by control loop theory. The trick seems to be determining exactly which variable in the loop is out of whack. Me, I go with the theory that a little bird needs tighter tolerances, and that the 250 doesn't have them, so oscillations can start because of delays caused by slop. (And that super-fast servo can help to make up for that.) If you don't like that theory, there's always posts 1-250...

Last edited by Harbormaster; 09-22-2013 at 10:52 AM.. Reason: Spelling
Harbormaster is offline        Reply With Quote Quick reply to this message
Old 09-22-2013, 01:49 AM   #252 (permalink)
Registered Users
 
Posts: 81
 

Join Date: Feb 2011
Default

You are most certainly right, I have read the posts before, I will do it again, especially post #1. I also like the idea of the loop theory, and I'll try and eliminate some slop from the tail first. Also I would like to extend the servo arm to 6mm because some Quark users report some success with that distance.
Still, I feel like I am searching for the classic needle in the haystack...
__________________
Blade Nano cpX, fully stock - Blade 130x, bling galore - Rex 250 Pro converted to FBL, 3GX - DS95i - HK 450 PRO converted to DFC, ZYX - Futaba 9257 - Rex 550 DFC, Beast X
gionir is offline        Reply With Quote Quick reply to this message
Old 09-22-2013, 10:53 AM   #253 (permalink)
Registered Users
 
Posts: 2,970
 

Join Date: Jan 2011
Default

What's REALLY frustrating is when you solve the wag and all is well (you think) and then it comes back.

Good luck!
Harbormaster is offline        Reply With Quote Quick reply to this message
Old 09-23-2013, 12:37 AM   #254 (permalink)
Registered Users
 
Posts: 268
 

Join Date: May 2011
Default

All wag in the 250 i've ever experienced/seen is due to the following:

Crap gyro - (which you don't have)
Crap tail servo - (I run the DS520/JR3500G servos)
Crap governor (or governor in general can do it if it's pulsing)
Bad tail grip bearings
'Sticking' in the tail assembly (grips, links, bell crank, etc).
Missing teeth in a belt.
Something in the teeth of the gear train that would add friction every rotation...

Basically, with the 250, everything must be extremely smooth. Ever since going to the 'mini' tail servos, I haven't had as many issues... still things here and there.
__________________
mCP X ||| mCP X BL ||| 130X ||| 250 FBL ||| 250 FBL #2 ||| 450 Sport V2 FBL ||| 450 Pro FBL ||| X5 ||| DX6i
Airman0386 is offline        Reply With Quote Quick reply to this message
Old 09-23-2013, 04:13 AM   #255 (permalink)
Registered Users
 
Posts: 1,458
 

Join Date: Apr 2009
Default

Your 250 must be tail heavy with 520/3500.

Even 306 is a clone of 95i, but sometimes, clone doesn't work as good as the original.
pinguin is offline        Reply With Quote Quick reply to this message
Old 09-25-2013, 03:08 PM   #256 (permalink)
Registered Users
 
Posts: 268
 

Join Date: May 2011
Default

Quote:
Originally Posted by pinguin View Post
Your 250 must be tail heavy with 520/3500.

Even 306 is a clone of 95i, but sometimes, clone doesn't work as good as the original.
Its not too bad actually. I dont even notice a difference in balance.
And, im not the only one that does it
Bert Kammerer - T-Rex 250 with Align GP-750 Gyro (4 min 44 sec)
__________________
mCP X ||| mCP X BL ||| 130X ||| 250 FBL ||| 250 FBL #2 ||| 450 Sport V2 FBL ||| 450 Pro FBL ||| X5 ||| DX6i
Airman0386 is offline        Reply With Quote Quick reply to this message
Old 09-25-2013, 05:20 PM   #257 (permalink)
Registered Users
 

Join Date: May 2006
Default

what is so different between this and the Gaui 200 tail? I never had these problems with my gaui 200 tail and I use a hyperion DS9 GMD servo.

I'm thinking of getting one of these and from what I read the mini size DS95i or clone variety is supposed to solve it, but if people still having problems even with that, I don't know if its worth bothering with.
robl is offline        Reply With Quote Quick reply to this message
Old 09-25-2013, 06:57 PM   #258 (permalink)
Registered Users
 
Posts: 2,970
 

Join Date: Jan 2011
Default

Quote:
Originally Posted by robl View Post
what is so different between this and the Gaui 200 tail? I never had these problems with my gaui 200 tail and I use a hyperion DS9 GMD servo.

I'm thinking of getting one of these and from what I read the mini size DS95i or clone variety is supposed to solve it, but if people still having problems even with that, I don't know if its worth bothering with.
The 250's tail instability is a an ongoing mystery (as you can see by the length of this thread and the variety of posts). If you're happy with the Gaui, maybe just stay with that? (They do look like cool little birds.)
Harbormaster is offline        Reply With Quote Quick reply to this message
Old 09-25-2013, 07:19 PM   #259 (permalink)
Registered Users
 

Join Date: May 2006
Default

Quote:
Originally Posted by Harbormaster View Post
The 250's tail instability is a an ongoing mystery (as you can see by the length of this thread and the variety of posts). If you're happy with the Gaui, maybe just stay with that? (They do look like cool little birds.)
It has its own issues,many of them, the tail just happens to not be one of them. But they are discontinued and the 250 has parts everyone.
robl is offline        Reply With Quote Quick reply to this message
Old 09-25-2013, 08:01 PM   #260 (permalink)
Registered Users
 
Posts: 2,970
 

Join Date: Jan 2011
Default

Quote:
Originally Posted by robl View Post
It has its own issues,many of them.
So do you think maybe small helis are just over all more demanding/less forgiving from an engineering perspective? You know--great big bird with a millimeter of slop in its linkage, no big deal; little tiny twitchy heli with a millimeter of slop in its linkage, major problem...

Just a guess, but I'll bet I'm right...
Harbormaster is offline        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © Website Acquisitions Inc. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

SEO by vBSEO 3.6.1