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Old Jun 11, 2012, 07:10 PM
Vzzznnnn...
vegos's Avatar
Greece, Attica, Athens
Joined Oct 2010
220 Posts
It's called stroboscopic effect (or reverse rotation effect).
It's something that happens because of frame rate of the video camera.
Imagine that your wheel is spinning 1000rpm. The frame rate usually is 24-30 fps (25 fps for PAL or 30 fps for NTSC), so you have the wheel in -let's say- 25 positions/still frames.
These 25 frames, due to the "distance" between them, when putted in series, they look like your wheel is spinning slowly, reverse or ever standing still!
You may have notice that on airplane videos, when the propellers are looking still in the air!

You can "recreate" the effect, by pointing your videocamera to any rotating wheel (with spokes is best) and watch the LCD. Try to change the throttle and watch the wheel to moving in the right direction, in the opposite direction and standing still.

(My english are terrible, but I hope you understand what I mean)

By the way, I admire your work trf_414_m2! Excellent!
(And I remember when I saw your video that some years ago I started to learn Spanish. I took only 3 lessons, and then I quit lol)
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Old Jun 12, 2012, 02:33 AM
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España, CL, Ávila
Joined Sep 2008
569 Posts
Thanks for the info and compliments, Vegos.

I took this video in Spanish for the spanish forum guys and I was ready to shot it in English too but I realized my pronunciation is terrible too...



I plan a subtitled one for foreign bikers...

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Old Jun 12, 2012, 02:47 AM
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Gartenzwerg's Avatar
Austria
Joined Jan 2007
663 Posts
No need for subtitles, your laugh at 1:34 says it all

In the beginning, when you turn the gyro wheel per hand, it looks like it wobbles just a little.
Is this just from the camera, or do you still have something to do?
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Old Jun 12, 2012, 07:49 AM
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patanegra's Avatar
Spain, CT, Rubi
Joined Feb 2012
30 Posts
You're a crack, César.
That desire to see how your project progresses!
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Old Jun 12, 2012, 09:19 AM
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España, CL, Ávila
Joined Sep 2008
569 Posts
Muchas gracias Pata...

Gartenz you´re right about the slight wobble on the flywheel. This is due to the poor quality chinese bearings I´ve installed on it and bearings are so close to each other too.

I need to get better ones with tighter tolerances.

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Old Jun 12, 2012, 06:13 PM
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España, CL, Ávila
Joined Sep 2008
569 Posts
The search for better bearings is over....

Went to Wiki to learn about the ABEC classification and search for ABEC#7 class bearings then.

Boca Bearings make several of this size and the orange seal series (ceramic balls) match ABEC#7 tolerances for wobble free operation. It´s time to order a pair or two (as spares), install them and shot another test.

More news. I´ve received a complete Quanum real wheel in order to test fit any of these cheap parts and get them before they become discountinued. Hope I can modify bearing carriers to accept 15x10x4 bearings or I´ll have to order custom ones to my machinist.
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Old Jun 12, 2012, 09:16 PM
PROFESSOR TRUTH JIMMY ICE
Akura2's Avatar
United States, CA, Los Angeles
Joined Sep 2003
6,738 Posts
Quote:
Originally Posted by trf_414_m2 View Post
The search for better bearings is over....

Went to Wiki to learn about the ABEC classification and search for ABEC#7 class bearings then.

Boca Bearings make several of this size and the orange seal series (ceramic balls) match ABEC#7 tolerances for wobble free operation. It´s time to order a pair or two (as spares), install them and shot another test.

More news. I´ve received a complete Quanum real wheel in order to test fit any of these cheap parts and get them before they become discountinued. Hope I can modify bearing carriers to accept 15x10x4 bearings or I´ll have to order custom ones to my machinist.
If I had known you were in search of the different bearing classes I could have helped... I used to roller blade so we had to deal with the bearing classes all the time... there are companies that make full ceramic bearings (balls and races) if you REALLY want to go all out... at the speeds your gyro will be running, it might be something to think about...
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Old Jun 13, 2012, 11:29 AM
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España, CL, Ávila
Joined Sep 2008
569 Posts
Thanks Akura.

During search process I´ve seen bearings of this kind. Absolutely awesome units...

... but excesively expensive ones for a custom proyect.

About the rotating speeds, even at 11.1v, I think I won´t go over 15.000 rpm at the flywheel. No need for F1 crankshaft bearings there....

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Old Jun 13, 2012, 02:19 PM
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herbie53's Avatar
Italy
Joined Feb 2011
53 Posts
complementar su proyecto .... muy interesante

jo tanbien estoy trabajando mucho tiempo ha carecido de un ARM radical.
por lo tanto, tengo unas cuantas preguntas

cuánto pesa tu moto ?
que el motor? 1:10, 1:8?
muy bien con las horquillas invertidas. es hidráulica?
mi consejo. construir un puente para los reguladores.
le dará una gran estabilidad
http://si6.mtb-news.de/fotos/data/18...ox_tora318.jpg

sigue así

ciao dani
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Old Jun 13, 2012, 06:08 PM
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España, CL, Ávila
Joined Sep 2008
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Ciao Dani.

Motor, 1/10, 36mm dia.

Weight data not available yet (peso todavía desconocido...)

Front forks, Ricky Carmichael front end, no oil damped nor USD yet (horquilla sin hidráulico de momento...).

Bruce, from 2wheelhobbies.com, had several option parts for this kind of forks. One of them was a clamp on fork brace, not available now (el puente de refuerzo está agotado y es dificil de encontrar...)

http://2wheelhobbies.com/product_inf...roducts_id=530

Grazie.
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Old Jun 14, 2012, 01:54 AM
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Gartenzwerg's Avatar
Austria
Joined Jan 2007
663 Posts
Willi from RCRacepro still has a similar item in stock, but at a different Price..
http://www.rcracepro.at/index.php?id...ttproducts_pi1[backPID]=95&tx_ttproducts_pi1[product]=294&cHash=d1c0f439ad1a6e4fc148f52c98727ae3

I`d go with a Venom VMX front end, or one from the new NuovaFaor Bike. Both hold oil and can be tuned. The VMX fork is pretty tough..
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Old Jun 15, 2012, 11:19 AM
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herbie53's Avatar
Italy
Joined Feb 2011
53 Posts
ok

mi opinión.
bicicleta completa meno 2 kilogramo = motor de 1:10
más de 2 kilogramo = un motor de 1:8
no sólo por tener "demasiado" poder, pero no recalentado esc, el motor y lipo....... si no masacre

quisiera montar un motor1:10 en un coche1:8 .. nadie hace eso

ya he cambiado el motor de mi moto. extensión tiempo de conducción , un motor / esc ni siquiera calentar un grado y muuuuuuuuuuuuucho energía

ciao dani
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Old Jun 15, 2012, 12:19 PM
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España, CL, Ávila
Joined Sep 2008
569 Posts
Your opinion is quite interesting but keep in mind that no manufacturer make their bikes for 1/8 motors.

An standard motocross bike (mechanical gyro) scales up to 3 kilo for 1/4 class, and provide very good performance.

Any E-gyro equiped bike will perform even better due to decreased drag on the drive train. AR Modelling guys calculated this (you can see it at their home page..) and suggest a 50% taller overall gear ratio compared with mechanical units.

Another con about using an 1/8 motor....

They´re so long and won´t fit inside caged chassis. My design feature a clamp style motor mount (any 36mm dia motor would fit) so I can install any 540, 550 or 1/8 motor, but I don´t want it to protude both right and left like any BMW boxer engine.

For low running temperatures, choose the right ratio...

For cold esc function, get one that exceed motor demmands by far...

For better lipo life, buy good ones built for high C numbers...
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Old Jun 15, 2012, 02:34 PM
RC Dirt Bike Action
JohnnyMc's Avatar
California central coast
Joined Feb 2010
1,802 Posts
The anderson m5 cross is 2.3kg, so it needs a 1/8 motor?? Have you seen the m5 wheelie on 1/10? Arx and Vmx are 3kg bikes, so they need 1/8? lol, that makes no sense. Not even 4x4 short course run 1/8 motors, but 550 on 2s and they are rockets. Your crazy Herbie.
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Old Jun 15, 2012, 05:30 PM
Registered User
España, CL, Ávila
Joined Sep 2008
569 Posts
More updates.

I´ve purchased bearing carriers from Quanum rear wheel in order to test fit them and a Quanum complete rear wheel too.

I´ve realized I could use the sprocket hub in my bike, but I had to mill the bearing bore from 13mm dia to 15mm. For the other side of the wheel, I need to order a much narrover custom bearing carrier.

I´ve compared both ARX and Quanum rear wheels too. Exactly the same design but very different material. ARX is so rigid and could be the hot ticket for SuperMotard while Quanum one is a lot softer, maybe good for MX...

About rear tyre, I´ve chosen the Proline Badlands for 1/8 buggy. Its soft, aggresive pattern, follows wheel shape perfectly. Quanum tyre is much heavier and feature two reinforced shoulders that make tyre profile much more flatter (not good for extreme banking...). I think I´ll keep this as spare for my Ricky.

Another pic of the progress so far.


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