no barrel sensor

[Jon Burford]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by prince sharma:
what m asking is if there is no barrel sensor who can we know in which gear car is running..? </div></BLOCKQUOTE>

Why do you need to know? your driver will know.
All you do is go up and down

[Fyhr]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jon Burford:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by prince sharma:
what m asking is if there is no barrel sensor who can we know in which gear car is running..? </div></BLOCKQUOTE>

Why do you need to know? your driver will know.
All you do is go up and down </div></BLOCKQUOTE>

Alternatively if you really need to know and don't want to modify the engine block for some reason, perhaps you know the engine speed and perhaps you know the wheel speed.

Assuming also, as this is an engineering competiton, you know some math.

[prince sharma]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Fyhr:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jon Burford:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by prince sharma:
what m asking is if there is no barrel sensor who can we know in which gear car is running..? </div></BLOCKQUOTE>

Why do you need to know? your driver will know.
All you do is go up and down </div></BLOCKQUOTE>

Alternatively if you really need to know and don't want to modify the engine block for some reason, perhaps you know the engine speed and perhaps you know the wheel speed.

Assuming also, as this is an engineering competiton, you know some math. </div></BLOCKQUOTE>


how can we program microcontroller to display gear on dash using engine speed and wheel speed?

[kcapitano]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Assuming also, as this is an engineering competiton, you know some math. </div></BLOCKQUOTE>

Hmm, an invalid assumption perhaps?

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> how can we program microcontroller to display gear on dash using engine speed and wheel speed? </div></BLOCKQUOTE>

That would depend on what microcontroller you're using, what programming language, how you are going to display the gear number on your dash, and probably more things...
Only you can figure out how to put it all together!

[Nicky]

Alternatively, I know I'm spoon feeding a troll now, but anyways.

Find the tailshaft rpm from the wheel rpm based on the final drive ratio you are running.

From the engine rpm and this tailshaft rpm, you can back calculate a ratio. This ratio includes the primary and secondary reduction from the crank to the clutch. You arrive at a ratio. Match this to the various gear ratios and you'll be closer to a given gear's ratio. Add a little tolerance to that and voila, you have which gear you are in.

Read the engine manual for the various reduction ratios. If you still do have a doubt after the handout I just gave you, I suggest you try this link
Basic Learning

[prince sharma]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nicky:
Alternatively, I know I'm spoon feeding a troll now, but anyways.

Find the tailshaft rpm from the wheel rpm based on the final drive ratio you are running.

From the engine rpm and this tailshaft rpm, you can back calculate a ratio. This ratio includes the primary and secondary reduction from the crank to the clutch. You arrive at a ratio. Match this to the various gear ratios and you'll be closer to a given gear's ratio. Add a little tolerance to that and voila, you have which gear you are in.

Read the engine manual for the various reduction ratios. If you still do have a doubt after the handout I just gave you, I suggest you try this link
Basic Learning </div></BLOCKQUOTE>

dude!! i am doing this first time so its little confusing.. stop making these pathetic comments..

[Rex Chan]

This reply is to Nicky.

First off, I want to say that I agree with Nathan about how it's good that you developed your system over time. I wish we had the time and patience to do this. However, this raises the question: is it worth it to spend the time to develop?

I also agree wtih Bemo that, all things being equal, a paddle shifter is a benefit (easy, consistant, fast shifts). But the important point is that things should be pretty good (i.e. your car is very fast) before paddles are worth it.

Onto the real question: you have clearly laid out the path it took to get paddle/pnuematics working for your team. Now I will do the same for mine (MUR Motorsports 2011 - mechanical solid linkage gear shift, cable hand clutch).

Timewise: it took 2 people a few hours to work out how to run a solid rod from the cockpit to the gear selector thing, through a bellcrank.

Weight: I weighed the rods and bellcrank, and it was less than 150g. I would guess the whole system weighs 300-400g, but def less than 0.5kg.

Cost: We already had the materials in our workshop, but if we had to buy it all, would cost not more than $50.

In summary, our system took a lot less time, weighs a lot less, and cost a lot less than your system.

However, you claim a significant time benefit (~6s per lap). If you have data to show this amount of time saving, I think most of us would very keen to see it. Or if you wouild rather not share, can you at least confirm this time saving? In my opinion, a paddle shifting system would save us in the order of 1 second per lap. This would not make such a system worth it for us.

Now, back to my previous question: "Is it worth it to spend the time to develop?" I think that it woud only make sense for a team to develop paddles is they were at the front of the pack in laptimes, where such a system would make a important difference. At both FSAE-A 2010 and 2011, MUR was 6 seconds behind the fastest teams. Thus, we have a long way to go before we are close to the fast teams, and the biggest gains for us are to be had in drivers and car setup (IMO).

May I inquire as to how off the fast teams your team is?

PS. A mechanical shifter does not depend on any other car system to work. And it works all the time (paddles have more moving parts to go wrong/fail).

PPS. We don't clutch on upshifts either, nor on downshifts (unless they get it wrong).

[Bemo]

I have to agree with Rex that 6s sound very optimistic as the time saved per lap by pneumatic shiftig. Including to propably less cones etc. I'd also go with 1s per endurance lap in average.

That's quite a lot. But without wanting to offend anybody, I have to say that Indian team usually have big troubles to get their car running at all. Adding an pneumatic system doesn't make it any easier to get it running.

Back to the original topic. There is a reason the CBR engine has only a sensor which detects wether it is in neutral or not - because in the motorbike you don't have a display which tells you which gear you're in. You just shift up and down and have to count or to know it by intuition / feel it. Same works for FSAE cars. The 2011 car from Stuttgart was the first one with a working gear sensor, but we were able to win quite some competitions.
As you mentioned it is the first time you're doing this and you're asking very basic questions my advice to you is to build a very simple and reliable system.
Compared to the usual performance of Indian teams it would be quite a big step to pass scrutineering without bigger issues and to finish endurance. Focus on that before you invest your time into the fancy stuff.

[prince sharma]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:
I have to agree with Rex that 6s sound very optimistic as the time saved per lap by pneumatic shiftig. Including to propably less cones etc. I'd also go with 1s per endurance lap in average.

That's quite a lot. But without wanting to offend anybody, I have to say that Indian team usually have big troubles to get their car running at all. Adding an pneumatic system doesn't make it any easier to get it running.

Back to the original topic. There is a reason the CBR engine has only a sensor which detects wether it is in neutral or not - because in the motorbike you don't have a display which tells you which gear you're in. You just shift up and down and have to count or to know it by intuition / feel it. Same works for FSAE cars. The 2011 car from Stuttgart was the first one with a working gear sensor, but we were able to win quite some competitions.
As you mentioned it is the first time you're doing this and you're asking very basic questions my advice to you is to build a very simple and reliable system.
Compared to the usual performance of Indian teams it would be quite a big step to pass scrutineering without bigger issues and to finish endurance. Focus on that before you invest your time into the fancy stuff. </div></BLOCKQUOTE>


so bemo what you suggest what type of transmission we should use..?? and regarding other issues of car running we will take care of that..

[shark.ashwa]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by prince sharma:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:
I have to agree with Rex that 6s sound very optimistic as the time saved per lap by pneumatic shiftig. Including to propably less cones etc. I'd also go with 1s per endurance lap in average.

That's quite a lot. But without wanting to offend anybody, I have to say that Indian team usually have big troubles to get their car running at all. Adding an pneumatic system doesn't make it any easier to get it running.

Back to the original topic. There is a reason the CBR engine has only a sensor which detects wether it is in neutral or not - because in the motorbike you don't have a display which tells you which gear you're in. You just shift up and down and have to count or to know it by intuition / feel it. Same works for FSAE cars. The 2011 car from Stuttgart was the first one with a working gear sensor, but we were able to win quite some competitions.
As you mentioned it is the first time you're doing this and you're asking very basic questions my advice to you is to build a very simple and reliable system.
Compared to the usual performance of Indian teams it would be quite a big step to pass scrutineering without bigger issues and to finish endurance. Focus on that before you invest your time into the fancy stuff. </div></BLOCKQUOTE>


so bemo what you suggest what type of transmission we should use..?? and regarding other issues of car running we will take care of that.. </div></BLOCKQUOTE>

Facepalm!
Please read Bemo's post again! I don't think you understood what he said......

Sharath