How Do I start with a pneumatic Paddleshift

[srikanth chilivery]

I am looking for a pneumatic paddleshift.
We are using a bike engine.
I want to use the arrangement of gearshifting as shown in the image.
http://img.tradeindia.com/fp/1/706/376.jpg
so i want help with the components, air supply, air storage and generation during run.
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I found that i could use a through rod double acting cylinder.

but i am unaware of the pressure of air to use.
Also please help me on the capacity of the reservoir and air generation techniques

[LemonFool]

Your use of a heel-toe shifter is inventive!

First, I would focus on having a storage tank large enough for an endurance run. Dealing with generation gets complicated. You can use a reasonably sized aluminum CO2 tank so you don't have too much extra weight. Something like this should have enough capacity Cylinder (http://sodadispenserdepot.com/pics/Reg9008.htm) . Your local weld shop should be able to supply you with CO2 regularly. Having to deal with running a flux capacitor for generation can be a headache. It's frustrating when you can't quite reach 1.21gw, and unpredictable when you reach speeds in the range of 88mph.

I would recommend a double acting actuator to keep the same shift pattern of the bike up and down. Something like this runs on a reasonable pressure, and is rated up to 180 deg Fahrenheit actuator (http://www.globalindustrial.com/p/pneumatics/actuators/pneumatic-actuators/double-acting-pneumatic-actuator-5859-in-lbs-80psi?utm_source=google_pr;utm_medium=cpc;utm_camp aign=Pneumatic-Actuators-google_pr;infoParam.campaignId=T9F) .

There are CO2 regulators with built in solenoids that you might look into using. Controversial, but when used right there can be some mind blowing experiences Solenoid CO2 regulator (http://www.amazon.com/AQUATEK-Regulator-COOL-TOUCH-SOLENOID/dp/B0041YLM7G)

But always look in the rules for the hard line regs and driver protection from blowouts.

[Rex Chan]

I would recommend you start by making a solid linkage shifter, and driving your car with it for a while. Then, if you still think the advantages of the pneumatic shifter are worthwhile, by all means, go ahead and make one.

We (Melbourne Uni) had unreliable pneumatic shifters up to 2008, went cable in 09 (too much slack + no feel), push-pull cable in 2010 (still complaince), and solid linkage via tubes in 2011 (awesome feel).

You get no feel with buttons. And downshifts, clutch control is needed, which means no manual clutch takeoffs. The only place I can see for a pneumatic shifter is ign cut upshifts for Accel: launch with human control, then hold on. ECU auto upshifts at shift RPM via ign cut, so perfect shifts every time.

Since you seem lazy and I am helpful: N2 or CO2 from dive/paintball shops in 12oz gas bottles (should last test sessions/comp/enduro). Therefore, refill before any track day. We used plastic compressed air fittings (push to insert, pull to lock).

But I would REALLY recommend solid, mechanical linkage: FSAE-A 2009/2010 1st (Monash) and 2010 2nd (Swinburne) used it, if you need results evidence to try and convince people.

For others reading this post: I think there is no question a pneumatic shift can be done well, with high reliability, but it seems that many in FSAE are not. ANother way to think about pneumatics is that to do a simple system, you don;t use feedback. This means its tuned under ideal conditions. If things start to go out of spec, then shifts may not happen so smoothly. You can preempt this by sensors for feedback (falling pressure, longer cut times, etc), but this adds mass/complexity.

WOuldn't it be great if there was a computer/controller on the car that could react and adpapt itself to almost any situation, was highly intelligent, reliable, quick, used no power, and added no mass? It's called the driver.

[TMichaels]

And downshifts, clutch control is needed, which means no manual clutch takeoffs.
I do not want to turn this into a general discussion about shifting systems, but it can be done without clutch control. We are doing it since 2005.

I second your opinion that a lot of time needs to be invested to get these things reliable and that it probably is not the first thing to add to your car. Real gains lay elsewhere.
However adding driver aids which really aid the driver by doing things for him in a way that he does not need to worry about it makes him faster by freeing capacity.


But I would REALLY recommend solid, mechanical linkage: FSAE-A 2009/2010 1st (Monash) and 2010 2nd (Swinburne) used it, if you need results evidence to try and convince people.
I would not try to argument that way, because you could also say: Use a 4 cylinder engine for the same reason...

Regards,

Tobias

[Michael Royce]

Tobias,
The strong recommendation, very strong in fact, to new or even newish teams, from those of us who have seen many teams fail to get a running car to the competitions, (and Pat and I have seen more than our fair share of failures) has ALWAYS been KISS! Keep it simple, stupid. Use a tube frame, a 4 cylinder engine and stock motorcycle gearbox, aluminium wheels, mechanical shift linkage and no fancy do-dads.

The biggest reason why new teams fail is that they underestimate the time it takes to build a car and try too incorporate too many "neat" (read unnecessary) ideas.

While the debate on single cylinder versus twin versus 4 cylinder to optimize fuel economy and performance is valid, for a rookie or young team that is trying to construct a reliable car that runs reasonably well, I would still recommend a 4 cylinder. Singles or twins can be rather finicky, and the 600 cc 4 cylinder engines have proven to be very sturdy and reliable.

[PatClarke]

Hear Hear Michael http://fsae.com/groupee_common/emoticons/icon_smile.gif

Pat

[TMichaels]

I second your opinion that a lot of time needs to be invested to get these things reliable and that it probably is not the first thing to add to your car. Real gains lay elsewhere.

Michael,
was the above part of my post in any way mistakable?

And this was only an analogy:

I would not try to argument that way, because you could also say: Use a 4 cylinder engine for the same reason...

Regards,

Tobias

[Michael Royce]

Tobias,
No. You, Pat and I are of an accord. I just wanted to reinforce what had been said to make sure that some of the new members on this forum, particularly from a certain, unnamed part of the globe, get the message.

[B Lewis @ PE Engine Management]

Michael,

I couldn't agree more. We have been doing this for a very long time (not as long as you, of course http://fsae.com/groupee_common/emoticons/icon_smile.gif ) and we see the over-complication of entries year after year. Just getting something to actually compete is challenging enough without all of the extras.