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Old Dec 20, 2008, 10:06 AM
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Nancy, in France
Joined Sep 2008
247 Posts
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Ricky with external gyro for trial/crawler

The objective is not to fall with very low speed







http://www.dailymotion.com/Lalain54/...torctrial_tech
http://www.dailymotion.com/Lalain54/...esouspont_auto
http://www.dailymotion.com/Lalain54/...totrial-3_auto
You can compare in the same zone with a crawler Enroute Berg 2.2:
http://www.dailymotion.com/Lalain54/...saiszone1_auto
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Old Dec 20, 2008, 10:50 AM
Flat out
W.C.mach's Avatar
Plymouth, MA
Joined Mar 2002
419 Posts
Wow that is truly amazing. I never thought that slow a speed could be possible. Warren
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Old Dec 20, 2008, 02:36 PM
AR Racing
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Italy, near Milan
Joined Mar 2005
930 Posts
W.C. the electrical gyro is really amazing....
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Old Dec 22, 2008, 12:30 AM
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Dubai U.A.E
Joined Oct 2003
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A very impressive development ..... please keep us all posted on this.

kevin@rcbike.com
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Old Dec 22, 2008, 10:43 AM
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Any idea what rpm your gyro is running at?

I have really been wanting to see something like this put to use on a moto-x bike...it would do away with that tank slap motion that the arx and ricky go through when they get out of balance...the physics that come into play with the gyro in the rear wheel set up that nasty oscillation ('tank slap')...damn vectors.
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Old Dec 22, 2008, 10:53 AM
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Warwick - UK
Joined Feb 2006
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Very nice, but remember guys, the more stable you make it, the harder it will be turn at speed.
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Old Dec 22, 2008, 11:35 AM
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Joined Feb 2005
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true true, but...you could basically offer the same overall effect on stability with a smaller gyro spinning at a lower rpm and the vector cross products that result from the gyro being laid over to one side or the other become more beneficial in directing the bike when the gyro is located closer the CG and you tend to reduce any system harmonics that would cause oscillations to be induced when something comes along to upset stability.

With the rear wheel gyro as the bike leans to one side or the other you get a net overall torque that wants to turn the bike about a line that runs from the contact patch at the rear wheel up through the axis of rotation, think of it like a pendulum with the pivot point at the contact point of the rear wheel...this can be seen in the videos when the bikes are suddenly upset and lean left to an extreme they tend to overcompensate to the left at which point the front suspension compresses and the steering locks causing a rebound to the right and the same occurs on the opposite side of the oscillation until the system either escalates in amplitude causing a crash or it diminishes due to system damping and stability is regained...blah blah blah...probably boring to most but the physics of these systems with mechanical gyro's really interests me.
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Old Dec 22, 2008, 06:36 PM
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Georgetown Ont. Canada
Joined Oct 2007
144 Posts
Has anyone ever thought to run a big outrunner motor in a Ricky and just add more weight to the outside. Maybe custom cut a sleve out of something heavy and press fit it over the outer rotating mass??? Would that give him enough gyro effect??? The outrunner could provide power and be the gyro all in one??? Might be compact enough to fit in the stock motor location and since it is spinning faster than the stock gyro it might not have to be so big or heavy???

You would also improve the bike's CG having the motor/gyro in the center of the bike.

Here is a large outrunner:

http://www.allerc.com/z50all.htm

Just a thought????


Hey chiller2030
Any chance that you could use some physics and design a jump ramp for me? LOL? When does the height of a jump start to degrade distance?

dave...
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Old Dec 22, 2008, 11:02 PM
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Nancy, in France
Joined Sep 2008
247 Posts
I have one 650g brushless motor:

http://www.rcgroups.com/forums/showthread.php?t=970961
How many lipos do you want to put on the Ricky ?
With the KV 235 and 20V (!) you'll have 4700 RPM. The gyro effect will not be enough: My gyro speed to 10000 RPM with Align T-Rex 450 (KV3200) motor. My gyro's wheel come from rear Ricky wheel with better diameter and 320 g "external" weight.
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Old Dec 23, 2008, 10:23 AM
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lalain-it would seem that on your crawler you are well served by a gyro with such a large effect...for those who want speed though the overall effect of the gyro could probably be half of what you have designed (-SWAG clause-)

Dave-the only problem with using an outrunner motor as you have described would be that you would need the rotating mass to continue to freewheel as the motor can moves through its range of operating RPM's, other than that it seems like a good idea and I am some of the rather industrious fellows on the board could easily devise a way to make that happen...
-regarding your ramp...what your dealing with is a classic case of projectile motion...what we need to figure your problem is the mass of ricky and the speed at which he would theoretically be projected into oblivion...
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Old Dec 23, 2008, 10:44 PM
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Georgetown Ont. Canada
Joined Oct 2007
144 Posts
Hi Chiller: I put two and two together the other day when I was working on my heli and saw this thread with the center mounted gyro. Maybe instead of pressing on a weight to the outer mass of the outrunner what about a one way bearing? If the bearing was heavy enough the outer race might give enough "gyro effect". You could alway raise the motor an inch to allow room for something to spin/freewheel.

On the jump question. My jump Ricky runs 32mph on radar and I want him to jump 80'. He clears 60' now but jumps very high. How high,long,curvature would I need for a ramp. Is there an equation I can use or jump curve? Optimum curve? There is a sharp design engineer where I work but I would like to give him some info first, instead of him just going at it cold. I know I have to take some height out of the jump to get him to go longer in the air just not sure how much. Ricky weighs aprox: 2.98kg or 6.5lbs.
Sorry if this is off topic.

dave....
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Old Feb 23, 2010, 02:42 PM
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Nancy, in France
Joined Sep 2008
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This is another good work:
http://norisbike.de/forum/phpBB2/vie...r=asc&start=15
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Old Feb 23, 2010, 06:22 PM
PROFESSOR TRUTH JIMMY ICE
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United States, CA, Los Angeles
Joined Sep 2003
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reminds me of the DARPA challenge motorcycle

DARPA: Team Blue Ghostrider (3 min 13 sec)
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Old Feb 23, 2010, 07:17 PM
Occasional useful idiot...
Joined Nov 2009
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Quote:
Originally Posted by davcat View Post
On the jump question. My jump Ricky runs 32mph on radar and I want him to jump 80'. He clears 60' now but jumps very high. How high,long,curvature would I need for a ramp. Is there an equation I can use or jump curve? Optimum curve? There is a sharp design engineer where I work but I would like to give him some info first, instead of him just going at it cold. I know I have to take some height out of the jump to get him to go longer in the air just not sure how much. Ricky weighs aprox: 2.98kg or 6.5lbs.
Sorry if this is off topic.

dave....
http://hyperphysics.phy-astr.gsu.edu...traj.html#tra7 Scroll down and you will find the ''Where will it land?'' box. Perfect for your needs! Best ramp angle is 45 degrees by the way and doing some checking reveals your Ricky needs more speed to jump 80 feet. 33.5mph theoretically on a 2m high ramp, I think!
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Last edited by Jonathan Bradbury; Feb 23, 2010 at 09:29 PM. Reason: Double checked and found a better link. and rechecked my sums!
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Old Feb 24, 2010, 12:00 AM
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Torrance's Avatar
Joined May 2009
661 Posts
Quote:
Originally Posted by davcat View Post
On the jump question. My jump Ricky runs 32mph on radar and I want him to jump 80'. He clears 60' now but jumps very high. How high,long,curvature would I need for a ramp. Is there an equation I can use or jump curve? Optimum curve? There is a sharp design engineer where I work but I would like to give him some info first, instead of him just going at it cold. I know I have to take some height out of the jump to get him to go longer in the air just not sure how much. Ricky weighs aprox: 2.98kg or 6.5lbs.
Sorry if this is off topic.

dave....
the weight of the bike doesn't matter. it's the bike speed and ramp geometry that counts.

i did some calculations... for 32mph you'll need a ramp that is 13.45ft high with a departure angle of 45deg to land 80ft down range. the curvature of the ramp doesn't really matter as long as the tangent angle at the lip is 45deg. 13.45ft however seems ridiculously huge for a ramp. and because the ramp is so tall the max height your bike will reach is 30.6ft.

i did some further calculations... if you can increase your speed to 34.2mph then you'll only need a 39.4inch high ramp (1 meter) with the same 45deg departure angle to clear 80ft (max height = 22.6ft).

my calculation used only basic ballistic equations which does not take air resistance into account but your time of flight is only about 2.5 seconds so unless you have a parachute attached to your bike we can probably assume it is negligible.

btw, if you use the 1meter, 45deg ramp at 32mph your bike will still clear 71.6ft. it's that last few feet that's a bugger.
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