ANY CVT's Out there?? (Continuous Variable Transmission)    Gallery
View related threads: (in this forum | in all forums)

Logged in as Guest



Users viewing this topic: none
    Search This Thread  
 
Printable Version



All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> RC Car General Discussions >> ANY CVT's Out there?? (Continuous Variable Transmission) Page: [1] 2   next >   >>  

Tower Hobbies Today's Special Offer! Brands Products
Login
Message << Older Topic   Newer Topic >>
ANY CVT's Out there?? (Continuous Variable Transmission) - 4/20/2004 12:55 AM   
BUGGIES_R_US



Posts: 3342
Score: 100
Joined: 12/26/2002
Last Login: 12/11/2010
From: Norcross, GA, USA
Status: offline 		Hey guys..

Well we know how it is.. we have the engine down.. but we only have 1-2 gears Damn transmission!!!

Enter the CVT or Continuously Variable Transmission!
CVTs are cool.. but they cant handle torque right? Well nitro motors dont have any torque!! Just mad HP!!

I realize most CVTs are electronically controlled.. but what about a MECHNANICALLY operated TOROIDAL CVT Tranny? Maybe make the cones shift with centrifugal device run by the OUTPUT shaft??

The only drawback is that CVTs NEED to be designed with a particular engine's power curve in mind.. but heck.. sell option parts!!
If people pay $100 for a Torsen Diff, They'll pay $200 for a good increase in Speed AND (yes thats AND) power!!!!

What a genius

ram

Hide Signatures
       Post #: 1

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/20/2004 4:43 AM   
Dr.ArmoMaxx



Posts: 1527
Score: 100
Joined: 12/22/2003
Last Login: 10/1/2009
From: Glendale, CA, USA
Status: offline 		hang on, this is first time i hear about CVT tranny, and i did some research on it, so it is 2 sprockets connected together with a chain or belt and it allows of use of various gear ratios? so it's expands whnever it reches particulat rpm? correct me please

_____________________________

Full throttle or go home.

Hide Signatures

(in reply to BUGGIES_R_US)
       Post #: 2

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/20/2004 4:52 AM   
ericheller



Posts: 2092
Score: 100
Joined: 12/1/2003
Last Login: 10/27/2004
From: defiance, OH, USA
Status: offline 		is it like the trannys in some audi's that dont actually shift but instead increase gear ratio with the increase or rpm's? if it is that seems way to complicated for rc cars, and i believe you have to have a special computer to control it.

_____________________________

watch my current video:
http://www.rcpics.net/view_single.php?medid=26872

Hide Signatures

(in reply to Dr.ArmoMaxx)
       Post #: 3

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/20/2004 5:02 AM   
popuptoaster



Posts: 171
Score: 100
Joined: 2/2/2004
Last Login: 7/15/2004
From: london, UNITED KINGDOM
Status: offline 		CVT, Continously Variable Transmision, dont have set gear ratios, in its most basic form it has two cone shaped pulleys next to each other, but facing opposite directions, one drivenh by the engine, and the other driving the wheels.

A belt conects the two, it runs from the smaller end of the engine driven cone, to the bigger end of the wheel driving cone. (lowest ratio)

As the engine revs rise the belt starts to move sideways, heading from the smallest end on the engine driven cone towards the biggest end, and on the wheel driving cone, its moving from the biggest end towrds the smallest. (highest ratio)

Easiest way to visualise it is to think of the gears on your 10 speed (or however many) bicycle works the same, but automatically and without the "steps" in the gearing.

They dont need complex electronics, Daf were builing cars with these trannies in the 70's with no gizmos. theyre version works by widening or narrowing the pully depending on road speed and engine revs



Some of our small cars over here are fitted with em, and they are somewhat odd to drive, you put your foot down and the revs rise, and the road speed sort of catches up gradually, like an autobox without enough fluid in it.

CVT sounds ideal for a nitro engine actually, dunno how well they handle high revs though?

< Message edited by popuptoaster -- 4/20/2004 2:04:13 AM >


_____________________________

If brute force doesnt work, your not using enough.


Hide Signatures

(in reply to Dr.ArmoMaxx)
       Post #: 4

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/20/2004 5:56 AM   
nitromacguyver



Posts: 829
Score: 100
Joined: 10/5/2003
Last Login: 10/15/2007
From: Plymouth, MA, USA
Status: offline 		technically we all have cvt's on all our vehicals w/rubber tires. when you get going the tire expands and the faster you go the more it expands. it is always changing size alittle or alot at a time. just a thought.

Hide Signatures

(in reply to popuptoaster)
       Post #: 5

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 12:45 AM   
jwren00


 

Posts: 205
Score: 100
Joined: 2/2/2004
Last Login: 12/8/2010
From: Denver, CO, USA
Status: offline 		If you have a snowmobile open it up and look inside. That is a nice example of a cvt. I bet you could make it work in an rc car, it would take up some room though which would be a huge problem

Hide Signatures

(in reply to nitromacguyver)
       Post #: 6

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 5:25 AM   
BOOCAKE4U



Posts: 186
Score: 100
Joined: 2/24/2004
Last Login: 3/16/2010
From: Pompano Beach, FL, USA
Status: offline 		kyosho actually did it more than 10 years ago with the 1:9 scale pathfinder/terrano and pajero cars...nobody has done it since as far as i know


(this is not my car, just always thought they were neat)





Hide Signatures

(in reply to jwren00)
       Post #: 7

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 5:31 AM   
nitromacguyver



Posts: 829
Score: 100
Joined: 10/5/2003
Last Login: 10/15/2007
From: Plymouth, MA, USA
Status: offline 		cool, what was the variation in the ratio on that thing?

Hide Signatures

(in reply to BOOCAKE4U)
       Post #: 8

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 5:45 AM   
BOOCAKE4U



Posts: 186
Score: 100
Joined: 2/24/2004
Last Login: 3/16/2010
From: Pompano Beach, FL, USA
Status: offline 		absolutely no idea

Hide Signatures

(in reply to nitromacguyver)
       Post #: 9

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 5:50 AM   
Dr.ArmoMaxx



Posts: 1527
Score: 100
Joined: 12/22/2003
Last Login: 10/1/2009
From: Glendale, CA, USA
Status: offline 		so it's like a real car tranny but scaled down?

_____________________________

Full throttle or go home.

Hide Signatures

(in reply to BOOCAKE4U)
       Post #: 10

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 6:03 AM   
nitromacguyver



Posts: 829
Score: 100
Joined: 10/5/2003
Last Login: 10/15/2007
From: Plymouth, MA, USA
Status: offline 		where did you get the info on that?

Hide Signatures

(in reply to Dr.ArmoMaxx)
       Post #: 11

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 6:03 AM   
BOOCAKE4U



Posts: 186
Score: 100
Joined: 2/24/2004
Last Login: 3/16/2010
From: Pompano Beach, FL, USA
Status: offline 		well, a scaled down CVT tranny (which are still pretty rare in the 1:1 car world)...doubtful that the 1:1 truck ever had a CVT, but it is a very scale model in other ways (solid rear axle and independent front suspension etc)

Hide Signatures

(in reply to Dr.ArmoMaxx)
       Post #: 12

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/21/2004 7:49 AM   
BUGGIES_R_US



Posts: 3342
Score: 100
Joined: 12/26/2002
Last Login: 12/11/2010
From: Norcross, GA, USA
Status: offline 		Man that CCVT is quite interesting.. I'd spend hours dis-assembling that thing if I had one

That picture about is interesting.. except I cant really see how that works..
But that is exactly what I'm talking about..

Yes they do have a sprocket system.. but thats probably too complex for our application.
They have some issue with handling torque because of the CVT fluid used in friction gears and because of the belt in chain driven sytems.
On top of everything.. many CVTs are very inefficient. Their efficiency come from use under non-accelerating conditions where they are as efficient as manual trannys. (~95% efficiency tops.. 30-60 when accelerating)


BTW.. Tires are built so they they do not expand. despite what you think.. a 17 in tire doesnt spin that fast... Your talking about 1200RPM to do about 60 Mph..
That means were talking about 9050 RPM !!!!!!
(Wheel size 2.2 inches with BIG round downs)

Just so you can double check me..

wheel size * pie (22/7) to get circumference.
then convert the answer to miles..
divide ONE by answer (1/Ans)
viola!

17*(22/7) = 53.428
53.42800 inches = 0.000843244949 miles
1 / 0.000843244949 = 1 185.89504 (smaller due to rounding down)


Now you could get technical on me and talk about angular momentum... but lets not go there

ram

Hide Signatures

(in reply to BOOCAKE4U)
       Post #: 13

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/22/2004 6:14 AM   
nitromacguyver



Posts: 829
Score: 100
Joined: 10/5/2003
Last Login: 10/15/2007
From: Plymouth, MA, USA
Status: offline 		ok lets talk angulare momentum. i dont know any thing about it so teach me. any way to show how much the tire expansion can effect the speed as a cvt, ill do the ###s for you.

normal tire size= 5 3/8 inches = 17.1 inches
fullspeed tire size = 6 1 /8 inches. = 19.2 inches

my truck can hit 45 mph topspeed. if the tires did not expand it would only hit (45* 17.1/19.2) = 40mph.

anyway tell me what angular momentum is.

Hide Signatures

(in reply to BUGGIES_R_US)
       Post #: 14

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/22/2004 7:36 PM   
nitrohead5300


 

Posts: 2744
Score: 100
Joined: 7/15/2003
Last Login: 5/23/2012
From: indpls, IN, USA
Status: offline 		I have been running rc cars since the 70's a rc car manufactory by the name of Thorpe made a 1/8 scale car with the continous varable speed tranny in it. The car had alot of invovations on it and if you adjusted the cvt right it was killer fast. Parts were kind of hard to get for it so it sort of lost popularity in the midwest which was delta country back in the days

Hide Signatures

(in reply to nitromacguyver)
       Post #: 15

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/22/2004 8:31 PM   
nitromacguyver



Posts: 829
Score: 100
Joined: 10/5/2003
Last Login: 10/15/2007
From: Plymouth, MA, USA
Status: offline 		do you have any more info on this buggy?

Hide Signatures

(in reply to nitrohead5300)
       Post #: 16

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 4/22/2004 9:57 PM   
lynx the great



Posts: 761
Score: 100
Joined: 8/12/2003
Last Login: 12/23/2006
From: indy, IN, USA
Status: offline 		I think it would take away from the "cool" factor!

and it wouldnt be ideal for any thing that will be jumping. IE MT, buggy, rally car

_____________________________

http://www.rcuniverse.com/mvp/mvpposts.cfm?memberid=63826

Hide Signatures

(in reply to nitromacguyver)
       Post #: 17

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 2/12/2005 1:30 AM   
glenn


 

Posts: 11
Score: 100
Joined: 9/15/2003
Last Login: 7/27/2005
From: Toronto, ON, CANADA
Status: offline 		A friend of mine designed and fabricated a cvt transmission for his engineering thesis. It's a really good idea especially because of the peaky nature of nitro engines. The biggest problem he ran into was getting a v-belt in the right size which is not a standardized part. To be honest I really can't believe that it isn't a common hop up part because the potential for improvement in acceleration over a 2 speed is great. To the guy that said that they are rare in regular cars there is a reason for that. CVTs for fullsize cars are not new at all some cars back in the 70's had them. The main reason they haven't been common is that they are based on a frictional drive belt that has not been able to handle very much torque. New materials are allowing cvts to handle much more torque and audi even has a complex chain belt that. The second main reason is that people when driving are used to the rpms rising proportionally with road speed when accelerating and they dislike the 'rubber band' effect that a has where the revs shoot up then the gear ratio changes to increase road speed. So cvts for cars which are electrically controlled are designed to act like a regular transmission with discreet gear ratios which kinda eliminates the point of them. I'd estimate that current planetary geared automatics will be history in maybe 10 years and cvts will take over from them. My guess why compainies haven't come out with them for rc cars probably has to do with fitting them in the chassis is difficult and they probably just found they haven't been cost effective. You know someone always has to be the first to put something out there.

Hide Signatures

(in reply to lynx the great)
       Post #: 18

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 2/12/2005 12:13 PM   
thunderw0lf



Posts: 626
Score: 100
Joined: 11/26/2004
Last Login: 4/11/2009
From: Joppatowne, MD, USA
Status: offline 		Polaris has been using that type of transmission in it's automatic 4wheelers for at least a few years now. It's a very smoothly accelerating transmission. The biggest problem with getting it into cars and trucks is the power curve is different and there is more to deal with. Belt technology is coming along and getting better but it still has quite a ways to got before a CVT is widely available, it'll be more than 10 years before they make our standard gear shifting transmission a thing of the past and a museum piece. With that said, there really is no reason there isn't one made for R/C cars except that no one wants one. If people were to write the manufacters and ask about them , and I mean lots of people and post on the companies message boards about them, they wouuld see there is interest, perhaps enough to invest the time and money to design and build one.

Hide Signatures

(in reply to glenn)
       Post #: 19

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 2/12/2005 3:02 PM   
Rich K.


 

Posts: 1
Score: 100
Joined: 12/11/2004
Last Login: 2/22/2006
From: milford, PA, USA
Status: offline 		These transmissions are starting to be used in cars today.If you look at the new Ford Freestyle and 500 they both use these cvt systems.I dont know but you might be able to get a diagram of one of those and find a way to make it work on an rc.Just my .02.

Hide Signatures

(in reply to thunderw0lf)
       Post #: 20

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 2/12/2005 11:58 PM   
thunderw0lf



Posts: 626
Score: 100
Joined: 11/26/2004
Last Login: 4/11/2009
From: Joppatowne, MD, USA
Status: offline
quote:

ORIGINAL: Rich K.

These transmissions are starting to be used in cars today.If you look at the new Ford Freestyle and 500 they both use these cvt systems.I dont know but you might be able to get a diagram of one of those and find a way to make it work on an rc.Just my .02.



Yea, just starting to be used in cars today. My auto mechanics teacher was telling his class about them back in 94 when there was a company in Britian I think that was testing an experimental prototype. The biggest drawback and still now although things have improved was beltlife. I understand they are starting to become or already a common transmission in Britain but people in the US do like driving their manual stick shifts and in general, CVTs can't handle the horsepower and torque yet from the bigger engines many cars and trucks here have.

Hide Signatures

(in reply to Rich K.)
       Post #: 21

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 2/13/2005 8:12 PM   
nitromacguyver



Posts: 829
Score: 100
Joined: 10/5/2003
Last Login: 10/15/2007
From: Plymouth, MA, USA
Status: offline
quote:

ORIGINAL: thunderw0lf

people in the US do like driving their manual stick shifts



lol thats funny. i know only 3 or 4 people that can drive stick. that will soon be 4 or 5 when i start driving stick.


_____________________________

Cen MT2 with lots of custom aluminum
XTM X-Factor with some custom aluminum

Hide Signatures

(in reply to thunderw0lf)
       Post #: 22

RE: ANY CVT's Out there?? (Continuous Variable Transmis... - 1/24/2007 2:38 AM   
Pete Harvey


 

Posts: 20
Score: 100
Joined: 10/30/2006
Last Login: 5/20/2010
From: LondonLondon, UNITED KINGDOM
Status: offline 		Hi

for those searching the internet for info on the 1/9 Kyosho CCVT pajero / montero/ 4runner I have just restored one that I bought off e-bay. The gearbox case is the weak point, but after some modification with fibre glass have got it working again. Have posted some pics & video on my websiite : http://pic6.piczo.com/fireboat/ would love to hear from others with these cars.



Attachments
Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize


Hide Signatures

(in reply to BOOCAKE4U)
       Post #: 23

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 1/24/2007 5:01 AM   
EschObfuscation


 

Posts: 63
Score: 100
Joined: 8/15/2005
Last Login: 11/9/2011
From: Collierville, TN, USA
Status: offline 		http://auto.howstuffworks.com/cvt1.htm

Here is a different style of CVT, a torodial CVT.

Hide Signatures

(in reply to Pete Harvey)
       Post #: 24

RE: ANY CVT's Out there?? (Continuous Variable Transmi... - 1/24/2007 5:53 AM   
MadDogRC


 

Posts: 723
Score: 100
Joined: 1/21/2006
Last Login: 7/25/2008
From: PerthWestern Australia, AUSTRALIA
Status: offline 		oi guys, is this concept that i have here a CVT or a completely different form of drive? if its not CVT what do u think of it?

Attachments
Click to see fullsize image.
Click for fullsize


_____________________________

If you can't beat RC, then build RC!

Hide Signatures

(in reply to EschObfuscation)
       Post #: 25



Page:   [1] 2   next >   >>  
All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> RC Car General Discussions >> ANY CVT's Out there?? (Continuous Variable Transmission)
Page: [1] 2   next >   >>  




Jump to:


 
Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

RC Universe is a service of Internet Brands, Inc. Copyright © 2001-2012.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America


0.734RCU1