Thunderbird 7



Alex Simmons

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Mar 12, 2006
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As requested, this is a bit of a repeat of something I posted elsewhere but some may not have seen it.

Since indoor training is now likely to be a bigger part of my life from here on, I've been gradually building up my indoor set up. I call it Thunderbird 7.

First was the multi-adjustable ergo bike with the dirty great flywheel and double reduction gearing:

IMG_0213.jpg


In the 4th gear of 7 (that's a Nexus 7 speed hub gear), at a cadence of 100 the flywheel is turning at ~ 600rpm. I'm not exactly sure how much the flywheel weighs but north of 30kg I'd say.

Chair is needed close by as I have to sit down to undo my walking leg attachment and screw on my bike leg attachment.


Then I added an SRM (I also have the adjustable length SRM cranks) which will go on when my buddy comes over one day to help me swap the BB out as I don't have the right tool (this SRM will end up on my road bike and will be replaced with another I have waiting to go on):

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Now I have a PCV with dual port to hook up the online option and have all the data available on a large screen in front of me as well as any pre-programmed work-out. I haven't invested in a dedicated laptop as yet, I haven't quite found that necessary but it's on the long list of eventual improvements.

All combined with a DVD/CD player, sound system and TV screen I threw together for not much $:

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And a weight plate with a very convenient hole to fit over the pedal for calibration checks of various power meters for $A15 (£8). I'll add a bit more weight with an extra plate soon:

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Then I picked up an industrial grade fan for ~ A$200 (£82):

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It's a beauty, really moves the air big time. In fact, I would go to say that training without having something of this order of air moving over you is sub-optimal.

It also protects the equipment as well, since I am no longer dripping like stupid as the sweat is being dried off my skin as it appears, all I really end up using the towel for is to wipe my brow.

Ha - I just spotted the pile of Championship medals sitting on top of the SRM box
biggrin.gif

There's a couple of others lying around somewhere... :D

Since then I have placed the perspex protective cover over the flywheel, which is kind of handy 'cause I can place a drink bidon on it and don't have to be concerned about how the towel hangs. And not that I have a cat, but if I did, the chances of it getting killed have been dramatically reduced.

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The cover did change the cadence - speed relationship as the air inside swirls around. I basically just use one gear higher than I did sans cover for similar power.

Here's a sample of a 2x20 workout from Thursday:

2x20Example.jpg


My next trick will be to get an MP3 player / iPod (yeah, that's right, I don't have one LOL) to load good training music onto as sometimes the CDs just aren't long enough. I wonder if that CD/DVD could play MP3 discs?

The other element of the project I was originally looking at was a way to control the resisitance through some form of electromagnetic braking. I haven't pursued that idea since, well, it works, works well and if I need to keep up a power level, then it's all up to me.
 

frenchyge

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Apr 3, 2005
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You'll need that resistance unit eventually as those interval sets gradually climb from ~250w to ~350w, won't you? ;)
 

Alex Simmons

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Mar 12, 2006
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frenchyge said:
You'll need that resistance unit eventually as those interval sets gradually climb from ~250w to ~350w, won't you? ;)
I think I'm safe for the time being. :p

Besides, I can assure you, this thing has more resistance than anyone could handle...

I just did a plot of the data from the efforts sections of the 2 x 20-min intervals. This is what it looks like:

Watssvrpm-1.jpg


On that basis, in Gear 5, 350W will be reached somewhere ~ 100 rpm.

And there are 2 more gears above that.
 

Alex Simmons

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Mar 12, 2006
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Here's a chart showing a 45 second seated lactate tolerance effort I did about 5 weeks ago. I forget what gear I used, I think it was 3rd gear. Here you can see the effect the flywheel has.

The power required to accelerate the flywheel is substantial.

Indeed the cadence (speed) only levels off after 27 seconds, even though power peaked after 13-seconds. That's a pretty normal curve for a similar effort on a real bike, perhaps the peak tends to be a bit higher on a road bike, depending on how you attack such an effort. Sometimes you "pace them" a bit.

LTI.jpg
 

Steve_B

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Dec 31, 2006
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Alex Simmons said:
My next trick will be to get an MP3 player / iPod (yeah, that's right, I don't have one LOL) to load good training music onto as sometimes the CDs just aren't long enough. I wonder if that CD/DVD could play MP3 discs?
It's easy enough to find out. I just realized the other day that my combo DVD player/VCR also plays audio CDs. It says so right on the front of the player. :eek: I use wireless headphones since I'm riding rollers most of the time and I like to watch movies during indoor training.
 

frenchyge

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Pretty cool. I rolled my eyes a little the first time I saw the barbell plate, but just noticed the *real* weight written in Sharpie below the nominal weight. That's more like the Alex Simmons whose work I'm familiar with. :)
 

Steve_B

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Dec 31, 2006
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Alex Simmons said:
Indeed the cadence (speed) only levels off after 27 seconds, even though power peaked after 13-seconds. That's a pretty normal curve for a similar effort on a real bike, perhaps the peak tends to be a bit higher on a road bike, depending on how you attack such an effort.
That roughly agrees with my efforts. How about showing the speed and torque too? I can guess what they look like but it might be interesting to see anyway, especially speed with that heavy wheel. Do you even have speed data?
 

daveryanwyoming

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Oct 3, 2006
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Alex Simmons said:
As requested, this is a bit of a repeat of something I posted elsewhere but some may not have seen it.

Since indoor training is now likely to be a bigger part of my life from here on, I've been gradually building up my indoor set up. I call it Thunderbird 7....
Very cool Alex. That's an impressive setup, it looks very solid and dang that's a big flywheel!
...The other element of the project I was originally looking at was a way to control the resisitance through some form of electromagnetic braking. I haven't pursued that idea since, well, it works, works well and if I need to keep up a power level, then it's all up to me.
Eddy current braking is a cool concept, leads to a small braking unit and enables the erg function, but who cares - that finned flywheel approach looks great, is consistent with the size of the trainer and based on some of the curves in your subsequent posts it does a great job of emulating road bike dynamics.

Thanks for sharing.

-Dave
 

Alex Simmons

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Steve_B said:
That roughly agrees with my efforts. How about showing the speed and torque too? I can guess what they look like but it might be interesting to see anyway, especially speed with that heavy wheel. Do you even have speed data?
I did try to hook up speed but damaged the speed sensor in the process. :eek:

Speed is tricky as I'd need to hook up the speed sensor to register either:
- the chainwheel driving the flywheel, or
- The flywheel itself.

Then I need to adjust wheel circumfrence accordingly. The former would be something close to normal wheel circumfrence, the latter would be some fraction of that, depending on the gear reduction ratio.

I didn't have enough speed sensor wire to safely reach the chainwheel via the tubing and so tried the flywheel approach. It worked but I was having trouble getting the sensor close enough to register consistently and in the process I got it a bit close and the damage screwed the sensor. There's a part of it somewhere in the room I have no idea where :p

Speed data in an indoor context is of pretty limited use anyway. Where it'd be most useful would be to keep the SRM ticking over for accelerations from a near dead stop so that you get a power data recording almost instantly, rather than the delay of 2-3 seconds that typically happens.
 

Steve_B

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Alex Simmons said:
and in the process I got it a bit close and the damage screwed the sensor. There's a part of it somewhere in the room I have no idea where :p
Decapitation of a speed sensor...

Alex Simmons said:
Speed data in an indoor context is of pretty limited use anyway.
Yeah, I know, but I still keep track of it and it goes into my yearly totals anyway, though it can be flawed. On my rollers at the lowest level of resistance, I can honk along in the 290 W area at around 30 mph (48 kph). Not real world unless your going down a very gradual decent.
 

swampy1970

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Feb 3, 2008
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Alex,

Thats a nice looking setup you have there!

As for the mp3 player - can't you just use Windows Media player that you have on the laptop and just set up a playlist?
 

Steve_B

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Dec 31, 2006
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Alex Simmons said:
Here's a chart showing a 45 second seated lactate tolerance effort I did about 5 weeks ago. I forget what gear I used, I think it was 3rd gear. Here you can see the effect the flywheel has.
BTW - I realize that you are doing a build-up but I was wondering if you normally include lactate tolerance work during a "base" build up. I've not heard of too many people doing it (though I know of some that do). Or is this because it's getting towards summer there and you are planning on doing some racing soon too? Just curious. I'm trying to pick people's brains about this sort of stuff.
 

Alex Simmons

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Mar 12, 2006
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Steve_B said:
BTW - I realize that you are doing a build-up but I was wondering if you normally include lactate tolerance work during a "base" build up. I've not heard of too many people doing it (though I know of some that do). Or is this because it's getting towards summer there and you are planning on doing some racing soon too? Just curious. I'm trying to pick people's brains about this sort of stuff.
Ordinarily no (well not planned specific LT work, usually normal riding and any racing takes care of it sufficiently), but I had a 500 m TT at the track a couple of weeks ago at my benefit night.

I did one back in August and the idea was to see how much I could improve.

That said, it still stresses the aerobic system as well and doesn't hurt to do a bit of this stuff now and then.
 

Alex Simmons

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Mar 12, 2006
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swampy1970 said:
As for the mp3 player - can't you just use Windows Media player that you have on the laptop and just set up a playlist?
That's a good thought. I would do that but the laptop shown is reserved for other use and the security settings required on it (not negotiable) make it unsuitable for the purpose.

I don't need a bling laptop or mp3/ipod, so I can prob pick up a good working unit for not much $.
 

Yojimbo_

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Apr 17, 2005
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Very nice rig. And to think you put it together yourself makes it even nicer.
 

tmctguer

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In the 4th gear of 7 (that's a Nexus 7 speed hub gear), at a cadence of 100 the flywheel is turning at ~ 600rpm. I'm not exactly sure how much the flywheel weighs but north of 30kg I'd say.

I would hate to be your neighbor if that flywheel ever breaks loose !!

seriously, that is a way cool home-made cycling machine.
 

Alex Simmons

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Yojimbo_ said:
Very nice rig. And to think you put it together yourself makes it even nicer.
I'd love to take the credit but it was a buddy of mine that built it.
 

J-V

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Love the name, Alex... Was there a Thunderbird 6 that I missed? :)

It's been amazing to see the incredible progress you've made, and it's inspiring to say the least!

Best,

Jeff

PS: [As an aside, for the longest time I thought it was dreams I'd had as a kid here in the U.S. All the adult guys I asked about the 'TV show with the rescue ships with the numbers on them' looked at me like I was crazy or something. Then one day about 15 years ago I was flipping channels, and there they were in all their glory on some geek station. I was relieved to say the least. LOL]