PADDLE SHIFT

[BIG G]

HELLO ALL YOU CRAZY CAR DESIGNING GANGSTERS OUT THERE THIS IS BIG G CHECKING IN FOR BIZNISS.
CURRENTLY DESIGNING ELECTRO-PNEUMATIC GERA SHIFT SYSTEM FOR FORMULA STUDENT CAR, HAVE ALREADY COME UP WITH SIMPLE CIRCUIT USING SMALL CYLINDER HELD AT CENTRE OF STROKE BY A 5 PORT 3 POSITION DOUBLE SPRING RETURN, DOUBLE SOLENOID ACTIVATED, CENTRALLY EXHAUSTED VALVE. USING C02 TANK FROM PAINTBALL GUN AND CONTROLLING TIMING OF SOLENOID ACTIVATION AND BLIPPING ON IGNITION COIL WITH A PLC PROGRAMMER. HAVING TROUBLE SOURCING PROGRAMMER AND WOULD BE GRATEFUL FOR ANY IDEAS AND GENERAL INFO. ON THE WHOLE SYSTEM.

[PatClarke]

Big G,
Speak English and...DON'T SHOUT!
PDR

[gug]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BIG G:
CONTROLLING TIMING OF SOLENOID ACTIVATION AND BLIPPING ON IGNITION COIL WITH A PLC PROGRAMMER. <HR></BLOCKQUOTE>

blipping on ignition coil? do you mean you are going to automate the blipping of the throttle on downshift? or are you talking about ignition cut?

oh yeah, and a shameless plug for a good guy: paradigm motorsports (http://www.paradigmmotorsports.com/html/shifter.html). keep his regulator in mind, i searched for a long while and went through alot of pain before i found this. also check out what hes got in development if you want paddles.

edit: the guy who runs Paradigm Motorsports is a cal poly pomona (i think) alumni and ex-FSAEr. his stuff has basically been developed for FSAE, although naturally is applicable to any motorbike engine.

[maxvdh]

I've got another plug -http://www.persistor.com/ - I'm not sure exactly what you're looking for, but check out their product. Very high quality and functionality.

Max
Drivetrain
Brown University

[BIG G]

more, more, MORE, MORE I WANT MORE!

[EgyptianMagician]

curious ... how 'unrealistic' is it to think that if you can accomplish an entire shift in say, 1/10th of a second, you won't need to worry about the 'ignition' blipping ?

any thoughts?

fyi ... use a microcontroller and you'll get all the timers that you need.

[rjwoods77]

Our car shifts in less than a ten of a seconds. Its a system called CVT. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[rjwoods77]

I might be mistaken but to mechanically keep things from grenading you might want to look into dog rings instead of synchros if the gearbox doesnt already use them.

[Charlie]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by EgyptianMagician:
curious ... how 'unrealistic' is it to think that if you can accomplish an entire shift in say, 1/10th of a second, you won't need to worry about the 'ignition' blipping ?

any thoughts?

fyi ... use a microcontroller and you'll get all the timers that you need. <HR></BLOCKQUOTE>

I think the ignition kill/retard is a must-have. It would take a lot of force just to pull the dogs out of gear while they are under load.

We already complete shifts in less than 1/10 of a second. Just make your ignition kill short.

[Denny Trimble]

Hey Charlie,
What kind of an upshift sensor do you guys use? Force, or position? We've only rigged up a position switch on the shift arm of the tranny, and it's not reliable enough to give any advantage over no-cut manual operation.

[Charlie]

Not sure what you mean. We have electronically activated pneumatic shifting so the ignition cut is activated by the same circuit that activates the solenoid. We have no position or force sensor on the shifter itself.

[bigfella]

We're using a microcontroller linked into MoTeC, CO2 from soda stream bottles and we get shifts in about 30ms. The clutch is small so quick shifting is easy, and we get 1500 - 2000 shifts per bottle.

[Charlie]

how are you quantifying that shift time? Lever travel? We use longitudinal acceleration peaks

[DanO]

Save weight and complexity, use buttons instead of paddles. Although i do agree that the "drool" factor is much greater for a nice set of paddles.

[BIG G]

Interested in this cvt system, what sort of system is it? I am still thinking of using paddles, is it a good idea to manufacture them or is it easy to find a supplier?

[EgyptianMagician]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
I think the ignition kill/retard is a must-have. It would take a lot of force just to pull the dogs out of gear while they are under load.

We already complete shifts in less than 1/10 of a second. Just make your ignition kill short. <HR></BLOCKQUOTE>

Ok I'll check into it. I'm still learning quite a big about the mechanical aspect. I pretty much have everything done "on the bench" and I'll hopefully be able to start engine tests soon. Like others, it's a electro-pneumo-mechanical (EPM - my thesis advisor coined that one for me!).

I'm just about to build a standalone test system for it, and one that is complete and everything is OK, I SHOULD be able to mount it on the engine/tranny and see what happens.

Mucho thanks for the help guys.

[Colin]

charlie
Richard wasn't quite write about our shift time, our ignition kill last's for 60 msec and last night I had a look through some of our data and using your method of g force peaks we are getting shift time's of about .1 of a second also

[Christopher Chow]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Denny Trimble:
Hey Charlie,
What kind of an upshift sensor do you guys use? Force, or position? We've only rigged up a position switch on the shift arm of the tranny, and it's not reliable enough to give any advantage over no-cut manual operation. <HR></BLOCKQUOTE>

My Team is looking into a sensor for spark cut as well. Im assumming you ask this becuase you have a manual shifter (no pnumatics)?
Since you want to initiate spark cut out at a specific force on the shift arm, a sensor that is triggered at a specd threshold would be ideal. Otherwise, using a positional sensor, any slop would throw things off.

I think DynoJet has something they offer with their "Power Commander" units that is a force/threshold activated switch that fits inline with whatever pull/push rod thats on the bike.

Anyone else using this piece or something like it? It would be nice to know becuase otherwise im just asumming.

[Denny Trimble]

Charlie,
I forgot you run pneumatic. Never mind http://fsae.com/groupee_common/emoticons/icon_smile.gif

Chris,
Yeah we use a manual shifter, and MoTeC has a "gear change ignition cut" feature. It can take a sensor voltage input as an upshift trigger. So far we've only used a position switch, which sucks, and played with strain gages and home-built amplifier circuits, with no success there either (more important things for skilled people to do in negative time...)

It's on the wish-list though.

[Spork]

I have been designing an electromagnetic shifter using components from our 2003 vehicle. We have had some excellent results useing both clutch and gear lever actuators + ignition cut.

What relability have people achieved with pneumatic shifters? Ie both with number of miss shifts encountered and damage to the gearbox.
Were you able to shift gears during wheelspin?
Also how did your drivers respond to the system? was there any feedback about making the car unstable in upshifts or downshifts. We found that stability was greatly affected depending on how the clutch was modulated.

[EgyptianMagician]

The only way (heheh famous last words are coming up) that I could see the pneumatic system failing, is if you leave the system open; that is you are not checking for successful actuation of both the clutch and the shifter.

Granted, I'm still in benchtesting mode, so maybe I shouldn't be commenting, but I've done a fair amount of research on the topic and I think I have most of by bassis' covered. Again, probably famous last words, but it's the best I can do for now.

I'm in the process of building a standalone testbench whereby we can input parameters for X amount of time and watch the system go through it's paces. With some skill and some luck I'm thinking that I could cover as many 'malfunctioning' scenarios as possible.

Although I didn't anticipate the ignition cut is the idea to alleviate the stress of releasing the clutch at 12000 RPM sort of deal? For that tiny burst of time which basically reduces RPM/stress (and increases life) on the tranny ?

One final thought, if you don't have a backup system, which to be honnest I really don't think you need one, design the system for 200% efficiency *you get the point* since if it breaks you're a dead duck !

[Colin]

don't get to excited there are plenty of ways for a pneumatic system to fail, TRUST ME. Most of our problems have stemmed from too much heat causing regs, lines and valve seals to fail due to over pressurising

[Igor]

I would suggest to implement a backup system as there will always be problems you didn't anticipate or are out of your realm of influence.
I have built a pneumatic shifter system only to see it cancelled as the car was finished too late. This didn't leave any time for calibration and putting an untested and uncalibrated system on your car is always a bad idea.

Colin:
What pressure did you run that it made your system fail?

Igor

[EgyptianMagician]

heheh, like I said "famous last words"...

Can you give some insight into the failure ?

So you're basically saying you had X pressure in the line and then the heating component actually increased that pressure in the lines ? ... if that's the case ...WOW.

Hopefully we'll be able to catch mistakes and such during testing, but I do see where you are coming from. Thanks.

[Denny Trimble]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by EgyptianMagician:
Although I didn't anticipate the ignition cut is the idea to alleviate the stress of releasing the clutch at 12000 RPM sort of deal? <HR></BLOCKQUOTE>

The idea is to upshift under full throttle by cutting the ignition (and not touching the clutch), which unloads the dogs of the tranny and allows a shift.

With a manual shifter, depending on the state of your used engine's gears and how many new / incompetent drivers you train, upshifting without the clutch will wear out the dogs in 2 - 24 months. In my experience, at least...

Whenever we rebuild an engine, we replace the gears that are worn, usually 2nd is the worst because of partial shifts through neutral that pop out.

[Colin]

we run around 50 psi in the lines but alot pf our problem's came from air in the lines overheating when there had not been a shift for a while, like queuing up for the enduro for the aus event last year in 30 + deg heat, the seals in the lightweight solenoid valves we were running couldn't cope with the extra pressure we had problems with the lines also but that was fixed with better quality line

[Charlie]

Just my opinion, but I think a backup shifting system is ludicrous. If you have such little faith in your setup either fix it or scrap it. I'm not saying it's bad to have a plan 'B' but two systems on the car? No thanks.

A design judge asked me that in semis last year. Shouldn't you/why don't you have a backup manual shifter? Same reason we don't have a backup fuel pump, backup ignition system, or why we don't run two chains. Because the damn thing works. http://fsae.com/groupee_common/emoticons/icon_wink.gif In the last three years, the only failures we've had were components that just wore out (pneumatic cylinder). Even then the system worked, just had the occasional missed shift.

The biggest problem I've seen with all the recent pneumatic shifters out there is that they are based on industrial pneumatic machinery hardware that just plain sucks. Plastic lines don't belong on a racecar. Neither do those crappy swivel push connectors. Solenoids aren't usually meant for the vibration, etc we see either, but we found some that work well.

As far as durability of the engine, an automated system will always be more repeatable than your average newbie shifter monkey. Also unlike a manual shifter, all your forces and timing are adjustable. So the thinking that an automatic/pneumatic shifter brings a higher risk of engine damage than a manual is totally unfounded. Judging by the comments I've seen on this board and the experiences I've seen in person, manual shifters (and thier required operators) are much more destructive. Denny's comments uphold this. In 5 years we've never had any transmission failures or any signs of abnormal wear. And I've had all our engines apart.

[js10coastr]

...make sure to use quality buttons

[rjwoods77]

First person to gps shift will be cool as hell. It was banned in formula one because it was so cool. Just a nugget for some nut to try out.

[Igor]

Charlie:
Well, you're working on iterations of a proven system. What I wanted to say was that when you're starting out with this stuff for the first time, you don't want to get stuck with a car that is completed the night before competition and then come to the conclusion the shifter system won't work and there is no backup plan. Actually this is the story of the first Delft car.
Of course I don't mean to have two systems on the car at the same time. Just keep all options open if you don't have a proven system yet. It's very hard for teams that are just starting out to not put the sexy bits on their car in favour of reliability.

Good point on the buttons, make sure they and their wiring are water proof as well. We had another car that would automatically downshift on left hand corners in the rain......at the competition http://fsae.com/groupee_common/emoticons/icon_frown.gif

Igor

[Spork]

Re: my original question on the previous page. What sort of relability are teams getting on the TRACK. Ie do you get many miss shifts.
I have found that what happens on the track is quite different to the lab, for example attempting to up-shift while wheel spinning can cause miss shifts. Do you get your drivers to lift off before a shift if there is wheel spin, or do your traction contol systems remove the problem or is it just not an issue?
What sort of driver feedback do you get?

Oh yeah and untill it's proven there should ALWAYS be a back up for any new system.

[Cement Legs]

Just out of curiousity, has anyone set up a pneumatic shifter without an ignition cut and used the clutch instead? If so any problems? If not any idea what problems might come up?

Our current design uses two bimba cylinders, one for the clutch and one for the shifter. Before the shifter can engage, a position sensor must read a successfull clutch disengagement. Are most people using engine cut-outs becasue it is easier? Would you suggest still using the ignition cut-off with the application of the clutch to allow the engine speed in the new gear (gear shifting into of course) to match up with the speed of the wheels thereby putting less reverse torque or braking torque on the engine. A good friend of mine is a very skilled bike rider and with a sport bike he will power shift under a lot of different conditions (ie up shift without releasing throttle, yes i know its harder on parts).

Also on downshifting, by not cutting the ignition, (ie letting the pedal determine throttle) could you not better control weather or not you want to downshift for braking or for power.

Anyway, some questions to think about. Any feedback would be terrific. I know we'll work it out next summer, didnt get into fsae 2005 so we'll have a whole extra summer for test and develop'nt, but any heads up will save us time and MONEY (got none that would be good). http://fsae.com/groupee_common/emoticons/icon_smile.gif

PS sorry bout long post
cheers

[MotoDave]

we are looking into a paddle shift system as well, and I was wrondering how you guys get the car into neutral?

[Igor]

You can either machine a new selector drum or have the cylinder send a shorter airpulse.

Igor

[Wilso]

cement legs,

does a single button control both cylinders? if so how do you take off or idle out of neutral? I must be missing something.
Last year we used a pneumatic shift with hand clutch without shift cut. You drive it just like a foot clutch...pull clutch in, release throttle, push button, let clutch out, pedal to metal. i sometimes down shift by only pressing the button. Sometimes we hit nuetral when going from 1 to 2 or I've missed a shift by pushing the button to fast or lightly.

[EgyptianMagician]

I don't quite understand the "pushing a switch too fast or too lightly" ... everything for us is timed via a microcontroller, you push a button, you get a timed burst (pneumatics fire) they maintain engaged until the the pulse is canceled and then the system is purged.

As far as the neutral shift is concerned ... either a second shift cylinder or like someone mentioned, a very short pulse, we'll see what happens.

So to answer the question. Button 1 - UP .. Button 2 - DOWN ..

[Wilso]

Our system was quite primitive last year. The buttons merely sent 12 volts to a solenoid that sent air to the cylinder. If you pushed the button too fast the solenoid opened and shut quickly so the shift was short or weak and didn't engage the next gear. Thus to get from 1 to N you just tap the up button. So during driving if you tapped the up button it went into nuetral or missed the shift.

[DanO]

We modified the trans to eliminate neutral. This made sure that we never hit neutral in between 1-2

[Didier Beaudoin]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DanO:
We modified the trans to eliminate neutral. This made sure that we never hit neutral in between 1-2 <HR></BLOCKQUOTE>

So you always had to hold the clutch at idle speed? http://fsae.com/groupee_common/emoticons/icon_confused.gif

[DanO]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Didier Beaudoin:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DanO:
We modified the trans to eliminate neutral. This made sure that we never hit neutral in between 1-2 <HR></BLOCKQUOTE>

So you always had to hold the clutch at idle speed? http://fsae.com/groupee_common/emoticons/icon_confused.gif <HR></BLOCKQUOTE>

we have a way of holding the clutch in, dont worry

[EgyptianMagician]

betcha it's Krazy glue !

[Marshall Grice]

Most of the modern bike motors have gear position sensors built in. working that in with a microcontroller takes care of pretty much all of the missed shifs as well as helping finding neutral.

Just out of curiosity, for those who are using longitude accel to determine shift times. What is the sampling rate on said sensor? Hopefully more then 10hz. I don't doubt that some are shifting faster then .1 secs.

[Garlic]

Can you give an example of a bike with a gear position sensor?

I'd say sampling rate should be minimum 50 Hz to get accurate results IF shift times are really under .1s.

[Marshall Grice]

we use gsxr's. they have one.

[Grover]

I highly recommend pumping your drivers full of stimulants and running a manual shifter. Cheap, light and reliable.

[Cement Legs]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Grover:
I highly recommend pumping your drivers full of stimulants and running a manual shifter. Cheap, light and reliable. <HR></BLOCKQUOTE>

BOOOOOOOOO 'note the use of capitals'

Cheers http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[innominate]

Hey all,

With your pneumatic systems, how are you getting your transmissions back into neutral?

We're considering a clutch lock-out, but I'd like to know another potential system as an alternative.

Thanks

[Garlic]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Grover:
I highly recommend pumping your drivers full of stimulants and running a manual shifter. Cheap, light and reliable. <HR></BLOCKQUOTE>

What type of stimulants do you recommend? http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

Manual setups will definitely be cheaper and lighter. But reliability is not assured of any design. I'm quite sure there have been quite a few manual sifter failures through the years.

It is a pet peeve of mine for people to say a certain type of design is 'unreliable.' It's not a purchased item!! YOU are designing it. YOU choose the level of reliability. Reliablility of a design is something you engineer. Saying a system is 'too unreliable' is like saying aluminum is 'too weak' to build anything out of. The reliablity of any design is in it's engineering.

I'm not saying pneumatics are the way to go... it certainly has it's drawbacks. Maybe a RELIABLE pneumatic system is too heavy, too expensive, or simply too time consuming to develop given your team's strengths.

But I guarantee there are teams with electronic/pneumatic shifting systems that have a higher degree of reliability than a few manual setups, so a blanket statement like that shouldn't be made.

[BIG G]

I think the use of pigeons has been greatly over looked. I have come up with a revolutionary new idea which is to train an every day, run of the mill pigeon to perch on your gear lever and by ways and means that could only be described as osmossis, I shall transmit my thoughts to the afore mentioned pigeon to select the gear of my choice.

[Cement Legs]

Pigeons tend to go into spontaneous flight under vibrations exceeding a mere 3 hz. How do you propose to balance your shift lever with all of the variations in terrain to assure that said pigeon will remain in position to complete the afformentioned task??? It doesnt sound like much reliability has been enginnered into your system.

[BIG G]

I shall enclose the pigeon in an imaginary cage via ways and means that could only be described as voodoo magic, and I am also planning to cunningly disguise the pigeon as a spanish sailor.

[gug]

hmmmm, i wouldnt choose a sailor myself, you know their reputation. the pigeon would probably be distracted male or female pigeons strutting around on the side of the track. why dont you try a knight? that way you could give it a jousting stick and by driving backwards around the track you could remove the competition.

oh yeah, vibrations above three hertz are in the pigeons bowel resonance zone... i would be quite happy if the pigeon took off!

[shifterEric]

I am from rutgers, I am not sure if anybody has seen our setup but if you have here is a little explanation that might or might not help out this paddle shift idea. Our paddle shift design was 2 years in the process, we've finally tweaked out all of the bugs and hit shifts 95% of the time. We use a R/C car motor hooked up to Bosch drill internals, and have that connected to the shifter shaft of our R6 motor. There is a program that was designed by one of our EE's to time and calbirate the ignition kill versus the shift point. Even with this program we've managed to shear dogs off the motor, so ignition kill is a necessary part of any electric paddle shifter. It is extremely quick for upshifts and give you an incredible feeling of shifting under full throttle. hope any of this helps you guys out. Eric

[drivetrainUW-Platt]

all this talk about pigeons....does it say anywheres in the rules that the car must be operated by one driver.....if not I think one could find a more suitable creature to run the car, but I will have to do some finite element analysis to determine which one will be best under load and what not.

[Pico2]

"Pigeons tend to go into spontaneous flight under vibrations exceeding a mere 3 hz. How do you propose to balance your shift lever with all of the variations in terrain to assure that said pigeon will remain in position to complete the afformentioned task??? It doesnt sound like much reliability has been enginnered into your system."

Best post on FSAE.com ever!

[Craig.]

Would you think perhaps monkeys could be of assistance? Anyone know the resonance zone for one of these little creatures? Thinking a small breed, monkey should be smart enough to change a gear

[Spork]

Re: shifterEric.

I can't believe you have sheared dog teeth off your motor. I have sone all my testing on a Honda F4 and after significant abuse during early testing it held together fine.
Also it's interesting that 95% was considered as having all the bugs worked out. Our system has not been used in a comp yet because it hasn't achieved 99% reliability (Ask your drivers how they feel about dropping into neutral when going into a hairpin corner at 10/10th's!)
I think reducing shift times is not the aim of these systems. The aim is to reduce driver involvement and increase vehicle stability. Fast shift times are a by product of this aim but not the object.

Also in response to a few other queries. Using electromagnetic solenoids is a funky way of having complete control over the system (including neutral). And for teams using both the clutch while shifting ask yourself, "What happens to the engine when we shift and the driver still has their foot pegged to the floor?" -Solution = ignition cut.

(or a monkey pushing back on the throttle although you would have to check in the rules if that would count as DBW throttle)

Also someone posted about using ignition cut on downshifts - wtf! (rev's need to go up not down!)

[gug]

yeah, the ignition cut on downshifts was what i thought big g said. probably not the best idea...

anyway, ive heard of an idea to use the cruise control throttle linkage to allow a microcomputer to blip the throttle on pneumatic (or not) downshifts. anyone actually done this? or any other sort of automated blipping of throttle on downshifts?

[EgyptianMagician]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Spork:

I think reducing shift times is not the aim of these systems. The aim is to reduce driver involvement and increase vehicle stability. Fast shift times are a by product of this aim but not the object.
<HR></BLOCKQUOTE>

YES! That was the initial concept, if you're decelerating and downshifting in a turn, imagine only having to focus on steering and throttle, just push a button to shift, that was the initial puprose. And yes, 'accelerated' shift times are 100% a by-product of this concept.

Good call for stating it.

And we're using a micro to do everything involved in shifting, we'll also have it interrupt the ignition when we UPshift http://fsae.com/groupee_common/emoticons/icon_wink.gif

cheers,

[Fred the Gypsy]

Yeah I had the same idea about using an IAC vavle to blip the throttle for the driver on downshifts however the rules comittee called it "electronic controlled throttling of the engine" and therefore deemed illeagal. Nevermiind the fact that it only has an open and closed position. The hilarious part would be that if we ran it they would probably have no idea what it does, damn my conscience.....

[gug]

thanks Fred, i hadnt asked for a ruling on that yet. too bad though, auto blipping would be cool.

[Adam Coombes]

Haha @ the pigeon posts.
Anyway, to the point, as my team are on a limited budget, and we already have far too much on our plate, we are looknig at a manual shifter design, cable operated.
After preliminary seatings of a 95th%ile person in the car, it is apparent that there is no room for a conventional gear shift lever. So we are considering a padle system mounted to the forward roll over hoop activating the gears via a push-pull cable.
Has anyone seen anything similar before? Or can forsee any problems that we are to encounter going down this route?
Any help much appreciated
Cheers,
Adam http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Greg H]

http://www.kengrimes.com/paddles.jpg Was that what you had in mind? Not my car, but I'll let the owner step up if he wants to tell you how it worked for them.

[Denny Trimble]

Some back of the pack team from Ithaca...

[James Waltman]

Denny,
Is it pathetic that we can tell which car that is just by that picture? Jack and I both recognized it right away.

I'm sorry I can't remember his name but we talked to the guy that made some of those components when we were packing up to leave Detroit. The bracket that holds the shift butterfly was very well made. He did it all with manual equipment (we are spoiled with CNC milling stuff so that was pretty impressive to us).

[Adam Coombes]

Thanks for the reply guys, does anyone know if the guy who designed it posts on here?

EDIT: found after a quick search its cornell racing, anyone have any other pictures? From the few i have seen, theirs looks like a mechanical linkage but cant tell if its a pushrod or cable linkage?

[Greg H]

Yes Adam, that was a cable. We have also used cables in the past and have had no problem shifting with them. Some of the older cars are going on six years without failure. The system is pretty easy to design too.

[Big D]

We use a manual shifter, and run a 3/4" 6061 Al tube straight to the shift arm (with a spherical end at the shifter, and the stock ball end at the motor).It does a little "S" to go around the seat, but it feels very solid, and is far lighter than a push/pull cable. So far it has worked very reliably, and is polished to a pimpin' shine http://fsae.com/groupee_common/emoticons/icon_cool.gif . I am sure you could also use this setup with a belcrank going over to the cornell style manual paddle....

[Adam Coombes]

We were originally going to go with a positive mechanical shift bar, but due to a lack or cockpit room, im thinking that the cable has got to be a lot easier to route.

Greg H: Did you guys use a single push-pull cable, or two pull one way cables?
Ive not had experience of 2 way cables, and im dubious to the amount of feel the shifter will give when the cable is being pushed to shift. http://fsae.com/groupee_common/emoticons/icon_confused.gif

[Derek Carboni]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Denny Trimble:
Some back of the pack team from Ithaca... <HR></BLOCKQUOTE>

I was on that back of the pack team http://fsae.com/groupee_common/emoticons/icon_biggrin.gif and it was a push pull cable. It had a solid tube at either end that could be used for mounting. And when combined with a small throw it had a lot of positive feel. Upshifts were pulls and downshifts were pushes. I found it easier to find neutral by feel than the solid link shifter we used to run and I never misshifted with the cable.

[Greg H]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Adam Coombes:
We were originally going to go with a positive mechanical shift bar, but due to a lack or cockpit room, im thinking that the cable has got to be a lot easier to route.

Greg H: Did you guys use a single push-pull cable, or two pull one way cables?
Ive not had experience of 2 way cables, and im dubious to the amount of feel the shifter will give when the cable is being pushed to shift. http://fsae.com/groupee_common/emoticons/icon_confused.gif <HR></BLOCKQUOTE>

We used a single cable. The only trick is that you need to guide it into and out of the sheath so that when you push it will actually produce a force on your shift mechanism. Actually, we only dropped the cable system for a solid bar because it was cheaper and lighter. I personally think they both have the same feel.

[Adam Coombes]

Cheers for the replies guys, single cable it is then! http://fsae.com/groupee_common/emoticons/icon_smile.gif

[EgyptianMagician]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Adam Coombes:
Cheers for the replies guys, single cable it is then! http://fsae.com/groupee_common/emoticons/icon_smile.gif <HR></BLOCKQUOTE>

hehehe ... thread topic "New Hotness PADDLE SHIFTING!" end result "Old and Busted Cable" ... sounds pretty damn reliable though.

I'll see how well we can make this pneumatic system work, worst case scenario, junk it and slap in the manual stuff.

cheers,