SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Nov 28, 2012, 02:54 PM
RC beginner
New York
Joined Oct 2008
6,054 Posts
yes, and like i said im not sure whether it increases or decreases stability on these quads. it really blew my mine when somebody suggested lower cg dont help a heli. i kept thinking "pendulum effect" but thats only true for planes. there were two thread that went on for hundreds of posts arguing the point. one was in (i think) sr70 fellows jar (just aint right) megathread where one aerodynamic expert was piled on by 20 guys who refused to believe. another thread was about the ball type frames used in some japanese copters where it was also eventually explained convincingly but took some effort. finally most of us came to believe lower cg did not make it better. i still have to think twice about it though.
dave1993 is offline Find More Posts by dave1993
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 28, 2012, 03:05 PM
Registered User
Joined Jan 2012
1,594 Posts
No wobbling with v929 (8 plug)/UDI hybrid!!!

I've just tested my new v929 8 plug replacement board from banggood.

There's no more wobbling anymore even if I use small motor diameters (115mm) !!!!
I've plugged UDI motorarms complete into the v929 frame as you can see.
The board is more stable than the v929 4 plug board, but it has slower yaw.
Speed is between the v929 4-plug and v939 yaw.
You can fly very agressive turns with this stability. Full Yaw stick doesn't let the quad crash like with the old v929 or the v939.

It does have same less lifting punch like the old v929 and I need more throttle to lift which seems to lead to shorter flighttime.

For Midelic: Weight is 28g / m2m diameter : 115mm

Ingredients:

* v929 8 plug replacement board
* v929 frame
* UDI 816 clockwise & anticlockwise motorarms
* MJX X100 props
mystman is offline Find More Posts by mystman
Reply With Quote
Old Nov 28, 2012, 03:33 PM
Registered User
midelic's Avatar
Joined Apr 2012
3,610 Posts
@mystman
Look for my mod of V929 main frame and cut off 1.6 grams.
with UDI motors every gram counts.

Sorry!Job conditioning.Now you have it....at least on this page.
midelic is online now Find More Posts by midelic
RCG Plus Member
Last edited by midelic; Nov 28, 2012 at 03:43 PM.
Reply With Quote
Old Nov 28, 2012, 03:37 PM
Registered User
Joined Jan 2012
1,594 Posts
Quote:
Originally Posted by midelic View Post
@mystman
Look for my mod of V929 main frame and cut off 1.6 grams.
with UDI motors every gram counts.
I KNOW ! It's just a try, if it works. You always must have the last words

Do you want to tease me ?

(After this try, I put the board back on a already weight reduced frame with 150mm m2m diameter)
mystman is offline Find More Posts by mystman
Reply With Quote
Old Nov 30, 2012, 03:45 PM
RC beginner
New York
Joined Oct 2008
6,054 Posts
recently somebody asked me "what was the ten cent tach mentioned in diy quad thread?". i thought people read EVERY SINGLE post on rc groups. lol! anyway here is a link to that i started some time ago which is somewhat related to the current thread:

http://www.rcgroups.com/forums/showt...9#post23197098

below are a couple photos that might be of interest in case you missed them. first shows scope trace of tach signal from a "weak" aliexpress motor with udi props on 4v. the second photo shows an s107 motor under same conditions. you can see the pulses are farther apart in the first one indicating lower rpm. looks like 1.2ms per blade for 23k rpm vs 1.9ms at 16k rpm:





ps stop teasing your brother or I WILL TURN THIS CAR AROUND RIGHT NOW!
dave1993 is offline Find More Posts by dave1993
Reply With Quote
Old Nov 30, 2012, 03:51 PM
Registered User
Joined Jan 2012
1,594 Posts
Quote:
Originally Posted by dave1993 View Post
ps stop teasing your brother or I WILL TURN THIS CAR AROUND RIGHT NOW!
We're both fine again, DAD
mystman is offline Find More Posts by mystman
Reply With Quote
Old Nov 30, 2012, 07:02 PM
RC beginner
New York
Joined Oct 2008
6,054 Posts
ok then. next stop... disneyland. ooh la la!

btw those are really fine constructions. i got couple meters of the square cf and considered canibalizing my v929 frame. but it does such an excellent job of lifting, far more than any of the direct drive quads, so i like to keep it in stock condition. maybe time to consider picking up a body from bangood. but i got half dozen goodies on the way now so probably will wait a bit. tgif.
dave1993 is offline Find More Posts by dave1993
Reply With Quote
Old Dec 08, 2012, 01:50 AM
Registered User
Joined Aug 2004
317 Posts
Anyone got their Syma-X1 control board? Recommended?
Raj Quest is offline Find More Posts by Raj Quest
Reply With Quote
Old Dec 10, 2012, 11:00 AM
RC beginner
New York
Joined Oct 2008
6,054 Posts
its now over a month since ive placed my order for one. im getting worried. funny thing is they get to the usa from china in 2-3 days. then sit in some warehouse right here in ny while homeland security checks them for fissionable material.

thanks a bunch george bush....
dave1993 is offline Find More Posts by dave1993
Reply With Quote
Old Dec 10, 2012, 11:11 AM
Registered User
midelic's Avatar
Joined Apr 2012
3,610 Posts
I got mine few days ago but unfortunately I'm not at home to test it.I'll test it in January.
midelic is online now Find More Posts by midelic
RCG Plus Member
Latest blog entry: DIY Multiprotocol TX Module
Reply With Quote
Old Dec 10, 2012, 11:16 AM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
14,507 Posts
Gents,
My Syma X1 fcb's arrived a couple of days ago after about the typical BG month of so wait. The only thing I've had time to check so far is to confirm they will bind with a FlySky protocol.
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
jesolins is offline Find More Posts by jesolins
Reply With Quote
Old Dec 11, 2012, 04:50 PM
Registered User
Israel
Joined Mar 2012
446 Posts
CW Motors Spinning Slowly

Hi All, I have finally received 2 v939 boards. After connecting all of the wires according to the drawing below, it looks like the CW motors are spinning much slower than the CCW and after raising the throttle to max once would take more than half throttle to start spinning again.
If I take one motor (doesnít matter which) and connect it to connector 1 in the pic Ė it spins ok but when I connect the same motor to connector 2 it goes slow.
This happens on both my v939 boards. Has anybody seen this behavior?
gilcd85 is offline Find More Posts by gilcd85
RCG Plus Member
Latest blog entry: Bixler FPV into the sunset
Reply With Quote
Old Dec 11, 2012, 04:57 PM
We can rebuild it!
djdavies83's Avatar
United Kingdom, Wales, Swffryd
Joined Apr 2010
3,669 Posts
My guess here is that you trim is set way off to the right, give it some left rudder trim.

I've still only had one DIY quad in the air so far so that all I can offer I'm afraid.
djdavies83 is online now Find More Posts by djdavies83
Reply With Quote
Old Dec 11, 2012, 05:02 PM
Registered User
LittleMo's Avatar
United States, VA
Joined Dec 2006
1,489 Posts
Quote:
Originally Posted by gilcd85 View Post
Hi All, I have finally received 2 v939 boards. After connecting all of the wires according to the drawing below, it looks like the CW motors are spinning much slower than the CCW and after raising the throttle to max once would take more than half throttle to start spinning again.
If I take one motor (doesnít matter which) and connect it to connector 1 in the pic Ė it spins ok but when I connect the same motor to connector 2 it goes slow.
This happens on both my v939 boards. Has anybody seen this behavior?
Does it fly? I notice often motors don't spin until I actually put it in the air.
LittleMo is offline Find More Posts by LittleMo
Reply With Quote
Old Dec 11, 2012, 05:47 PM
Registered User
Israel
Joined Mar 2012
446 Posts
Thanks all! Next time just tell me to switch RUD and AIL
Works perfectly now - what a great little quad!

My build:
- red/blue aliexpress 7mm motors
- v939
- bamboo frame (m2m 135mm) with PU enamel impregnated motor mounts
- LB props
- 260mah battery.

Overall weight including battery: 30g
gilcd85 is offline Find More Posts by gilcd85
RCG Plus Member
Latest blog entry: Bixler FPV into the sunset
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Lets Build a DIY FPV Spider Quad Together Nick_P Scratchbuilt Multirotors 172 Aug 21, 2014 04:50 PM
Sold DIY Open Pilot CC micro/mini quad BNF for sale Hamanu Aircraft - Electric - Multirotor (FS/W) 4 Aug 03, 2012 07:29 PM
Discussion Any good premade DIY Centre plate for AP Quad? redblur Multirotor Talk 2 Jun 24, 2012 08:10 PM
Discussion DIY Quad Frame hits snafu... srs5150 Multirotor Talk 5 Apr 30, 2012 10:46 AM
Discussion Looking for a good DIY guide for a 450 sized Quad nige838 Multirotor Talk 2 Apr 28, 2012 02:44 AM