PoC Cerebral or the trek tt lid. Everything looks damn good though, I wouldn't change squat.

Well instead of guessing you can test without a windtunnel, enter the platypus thread.

Also, you can save a pit of drag by getting rid of the basket on your pink bike.

Yup. Before heading to A2 last year I tried several attempts around the homestead and was very unsuccessful. Speed sensor (tried two) didn't play nice with my Garmin, there is no optimal route (near by), I live close to a mountain that seems to make my neighborhood quiet the wind tunnel (even early in the AM), and it's tough to fit in my schedule.

I have a lot of respect for those that can get out there and get good data, but for me I've all but given up on testing. Thank you for the suggestion, though.

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You look ridiculous.... ridiculously fast.

Great, great position...really looks good. If you're going for UCI legal, make sure the tips of those extensions are at the maximum 10cm allowed (although we measure to the back of the pad instead of the middle to allow for crazy commissionaires).

If that's your race suit, I'm guessing (it's always just an educated guess) that's where you should be looking for aerodynamic gains first.

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Hi Jim. Thanks for the complement, it means a lot coming from you. At A2 I managed a 0.198 CdA and I'm hoping I didn't loose any or too much of that switching the extensions and stem (and that was with the Pactimo suit). I tested Hincapie's Speedsuit (as I had one of those as well) and it was slightly slower at 0º while marginally faster at 10º. The fit of the Pactimo suit bothered me (especially with the extra material in the chest and gut) and like you suggest clothing is where I focused my initial efforts. I feel I did that by swapping to the BP 3.0. The BP 3.0 fits flawless and while I have no data on whether it is faster or not I don't know why/how it could be slower. The reason why I used the Pactimo suit in this latest video is that it's a much looser, and therefore comfortable fit to move around in, as the BP 3.0 doesn't lend itself to movement outside of holding an aero position.

As far as UCI legal, that is a concern as Master's Nationals was a goal; however, i've been having some health issues for the last 18 months that have hampered training and dropped me 50 watts from what I used to be able to sustain for 40K. I might have gotten a handle on the cause and it has motivated me to start tinkering again. Yet, even if I can get my 50 back I'd probably need another 15 or so to really be in contention and until both those things happen I'll play it fast a loose with the extensions.

Edit: Measured and the tops of the shifter-pods are 85mm above the pad's center and back. My hold is deceiving as I'm grasping air with middle and index fingers. Only my pinkie and ring fingers grasp the shifters.

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Revisiting this thread, as I've made some changes (meet UCI guidelines for reach and saddle setback) and the suit I thought fit flawless actually has some significant wrinkles. I changed from the Pactimo (which was good for sub 0.200) to a BP3.0 and looking at the tunnel photo the pactimo looks very loose in the shoulder area as well as having significant wrinkles. The BP3.0 looks much better in the profile view. It also fits much tighter in the shoulders, but it looks to have significant wrinkling in that area as well. I have little doubt that the BP3.0 is faster than the Pactimo, but I am curious if I should be looking at a suit that might remove these wrinkles (perhaps customs is my only option?).

My question to the aero gurus out there is do these wrinkles pose a serious CdA hit?

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Following along in the 1x10 thread I stumbled across the FEA work on the Trinity and it seems that exactly where my wrinkles are is where the highest pressures resides. Not sure how that plays into having wrinkles, but I am working to eliminate those wrinkles by how I wear the suit.

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You can somewhat intuit what's going on in that image, but the way to interpret the colors is that red zones are relatively stagnant, low-shear areas, while blue regions are higher-shear areas where the velocity is highest against the surface. So given that, other than *possibly* channeling flow via the wrinkles (though not very likely) you should be most concerned about what you do in the blue regions, or rather, how to get the most even distribution of blue regions. What's most likely to occur is that you have loose fabric in a high-shear/low-pressure area - and that will cause fluttering and total pressure losses.

I often see people comment that such and such area is "low pressure" because it's in a wake... which isn't quite right; rather almost always wrong. Total pressure losses should be distinguished from static pressure changes.

Great explanation, thank you. Now, if I only had a model of myself I'd be all set. So, based off of that model I shouldn't worry too much about my suit's current fit, but if I can get some wrinkles out it's probably not a bad thing, either.

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My opinion here is that what's shown on that model is not of much value as displayed because those results are rather obvious - stagnation pressure on small, blunt surfaces normal to freestream, and high velocities on tangential, maximum-cross-sectional areas.

Being able to make improvements based on who-knows-what kind of model seems like a stretch for anyone who doesn't know the details of how it was constructed and modelled, and for fluid dynamics experts/aerospace engineers (maybe "aerodynamicist" has become a polluted term like "nutritionists"), the information shown shouldn't be too surprising based on basic principles. So really, my recommendations are suggestions based on general principles rather than what is shown in that specific model.

Fair enough, an unknown model is a poor example to use to determine if wrinkles on me are bad (kinda knew that). But if it is obvious (based on general principles) that the inside of my shoulders are an area that will create stagnation does having wrinkles there worsen that? Is it beneficial to improve airflow where there is stagnation? Does removing said wrinkles improve airflow? You suggest I should concern myself with loose fabric in the high-shear/low pressure areas, but there is no loose fabric on that suit. Therefore, I focus on the only question mark, which are the wrinkles.

I plan on heading back to the tunnel soon or perhaps set something up with an alpha mantis partner (if they get back to me), but I'd kind of like to narrow some things down. I've done the position work and even though some things have changed I don't think there is a lot of low hanging fruit there. Consequently, I want to have equipment picked out that I might look to improve on and the suit happens to be one of those. Just asking if I'm barking up the right tree or if I should move onto something else.

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There's more to be concerned about than simply having wrinkles, mainly in knowing that high shear is a source of skin friction, but also that it where you have healthy shearing forces the flow is still attached - hence my comment on spreading these regions out. Any rapid decrease in cross-sectional area will encourage separation. You may be able to "feel" these differences with different head positions; I know that depending on my head positions I can feel flow changes on my shoulders or shearing forces along my back with varying strength and extents downstream. I think there's value in getting to know what positions "feel" like in the wind, knowing that you'd like to feel the flow attached as long as possible without strong concentrations of pressure or shear, e.g. If you feel high shearing in the upper back area, you'd probably be better off flattening that region and letting some of that energy flow further back.

Two things I notice. First, you bought the BP3 a size too large. Go down a size and most if not all the wrinkles will be gone. I cram my pudgy butt in a small and I am 5'10" and close to 170.

Did you try the Selector with the other tail section in the tunnel? That might allow the tail to integrate a bit better with your back and you might be able to see a bit better in your lowest position.

As an aside, I have been testing my old Selecter against a P-09 and the new Specialized. I don't have totally conclusive results yet, but so far the Selecter looks to be a bit faster on me.

For better or worse I unfortunately do most of my Time Trial training on the trainer and only venture outdoors occasionally. When I do get out I am usually doing a dry run for a Time Trial, so I focus on pacing and power production with little thought as to how the air feels along my back. However, I think you are right in that there is value in knowing what different positions feel like outside. I know my time in the tunnel gave me a feel for how the wind should feel going around my head and over my shoulders and I try to replicate that, but some things have changed, which may lead to a different feel. I'll pay more attention to my back and how it feels. Thanks for the tip.

On that note I noticed something strange this past Sunday when I went out on one of my "dry-runs", the POC made some serious whistling sounds when I was in anything than a perfect position. I know my Wingspan did the same thing when I was head down and that was a sign/reminder for e to get my head up. I'm curious as to the losses when this whistling is occurring. I would have thought that the Cerebel would have been better in all positions except maybe the best one (vs. selector). It should be noted that I never hear whistling from the selector no matter my head position.

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I thought a small might be too big, as well. I base this off my previous suits: Hincapie and Pactimo. Both of those guys are XS and you can see how poorly they fit in the photos below. I feel like they are more a medium size, but I guess they disagree. I'm 5' 6" and in those photos weighed ~135.






Our current clothing supplier is Castelli and we have a pretty good relationship with the rep. Castello's custom stuff in XS fits me spot on; however, the BP3 is not available in custom and the smallest I could get was a small. Had an XS been available I would have gone that route. That being said the BP3 fits pretty damn tight and looks like a baby's onesie when not worn, but you know that.

My flexibility is about as bad as it gets and my neck is no different. I turtle pretty well but it's not easy to do. Getting the tail down on the selector with the short tail was hard work for the short runs in the tunnel, let alone holding it for 50+ minutes. We shied away from that quickly as the long tail proved just as fast and was easier to hold (.213 for long vs .214 for short). Never tried it once we dropped my front end, though. might be a consideration when I go back.




Lastly here are some photos with my extension pushed back out (realized that USAC will not "strictly enforce" UCI reach and saddle setback guidelines at Nats). Also, the POC to contrast with the selector.

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I have a POC Cerebel and notice the extreme whistling with a head down attitude when I have the visor on. I think it's primarily from the ventilation slots in the visor, but I haven't tried to really diagnose it. I'm not sure if you're assuming the whistling is causing a loss, or if you're just thinking that the whistling correlates to a poor position. All sounds are energy, but the defining characteristics of soundwaves are that the waves are isentropic and therefore not lossy; so it would have to be the mechanism causing the sound to be lossy for the first case to be realistic. I doubt the whistling is correlated with anything in particular for this helmet other than a certain head angle, which may or may not be a good head angle depending on a lot of things.

The navy colored portion of the Cerebel is a thin plastic molded bit. As you can see from the photo it is stopping the helmet from rotating back and I am actually not clocking the helmet any due to this. Has anyone trimmed this bit to customize the fit?

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