Helmet Aero Mods - Page 2

landspeed · 09-20-2007, 11:49 PM

Maybe the quieter helmet makes you sit up more, or go a little bit faster, as the buffeting doesn't put you off as much?

CoyoteX · 09-21-2007, 08:20 AM

no change with todays trip.

So I guess the conclusion is I need better measurements. I think testing a bike like this is not going to work.

98miles / 1.8 gallons = 54.44mpg Seeing as how the pump only reads to a .1 increment I figure a +/- of .07 gallons would be reasonable. so that gives a range of 52.4 to 56.6 so really .5mpg means nothing other than I sometimes go a mile or so extra and get lunch so that slightly changes my numbers but there is not enough accuracy in filling up to be able to see the change.

So I guess that means in order to test a bike I need a much bigger tank to minimize the errors. Either that or maybe figure out a way to weigh the gas so I can get a more accurate idea of my fills. I might try getting a pair of bathroom scales and put the bike on it before and after a fill and see if the difference in weight gives better sensitivity than the gas pump. One gallon weighs from 5.8 to 6.5 pounds, depending on the temperature when you weigh it. So I think coming up with a decent system to weigh the gas might be hard but not impossible. Getting gas in a measured container and using that to fill the tank might also be an option. Once there is an accurate way to measure the gas I might be able to redo this experiment.

edenstrang · 01-05-2008, 11:13 AM

I was considering trying the trip wire on an older helmet I had as well. The classic diagram of the sphere with a trip wire has the wire ahead of the largest cross sectional area. I can't find the image right now, but I'm sure you know which one I'm taking about.

I wonder if the gains would be better having the tape across the forehead, maybe along the upper edge of the visor so it doesn't interfere with operation.

I know this is an FE mod, but on mine I'd probably just gauge success by reduction of stress on my neck, and helmet noise, no?

CoyoteX · 01-05-2008, 10:19 PM

I can't remember where all I tried it at but where it is in the pictures is where it had less pressure on my neck. I ran it towards the front and farther to the back but for how I sit on my bike were it is at is how it worked good.

I changed helmets a bit after I tried this and the new helmet is way quieter and doesn't try and push my head back like the old one so I haven't bothered with the foam on it. I think this is one of those things that you can do for practically no cost so you might as well try it. A 25ft or so roll of that foam insulation tape is like $3 at a hardware store. You can put it on the face shield opening to help seal it and make it quieter so it is handy to have either way.

GasSavers_SD26 · 01-06-2008, 04:38 AM

At higher speeds at places like Daytona, we get a lot of buffeting from the air flow off the front windscreen even when you're down on the tank. Braking into the chicane and into turn one, you pop up to use your body to break the wind, get a better view, and use some leverage to turn the bike.

At the highest speeds, there's enough drag on some helmets that you get a real lift on the helmet that makes you feel that it's getting sucked off the top of your head.

The manufacturer of the helmets that I use, changed the top of the helmet to change some of the ventilation and to reduce that lift.

This was the original helmet shape.

This is the "extreme" design shape. Notice the little rear spoiler. It's just a plastic piece glued to the top of the helmet. Thin too. I can push them in with my finger, and they flatten out, or break, depending upon the impact.

I can't say that it helped our fuel economy, but at speeds probably above 100, there was a real difference in how it felt. Seems like you might be going in the right direction.

GasSavers_Otto · 04-02-2008, 04:40 AM

Quote:

Originally Posted by Coyote X

I have read on here and a few other sites people doing a simple mod to their helmet to make it quieter and have less wind drag. It isn't a boat tail but that would probably look pretty strange on a motorcycle helmet anyway

I just used foam tape normally used for insulation. I was sealing up all the gaps in the face shield anyway so adding a bit more around the outside over the top was no big deal. I rode with it to work today and it definitely is better. I can go up to about 80mph without it trying to push my head backwards. It is also quieter, the low frequency booming sounds are way less. I stopped and adjusted it a few times, where it is at in the picture worked great for me. If you lean forward on your bike it might need farther back but it can be pulled off and re-stuck without much trouble for a few hours till the glue sets up on the tape.

I have one trip on it going to work but I did not drive my normal speeds I was going fast and slow and stopping to adjust the foam. I should get enough normal driving miles on it this weekend and next week to see if it is a measurable difference in mileage. I figure I need at least 300 miles or so on it then I can peel it off and try another 300 or so miles. This best test I can really think of on a bike, cause there is not really a good way to do an A-B-A test that I can think of. I guess if I had a lot of time and an iron butt I could do a 100 mile test loop for the runs and fill up between runs but I don't think I will be trying that anytime soon.

Why not use some pinking shears and make that foam into zigzag tape, as is used on high performance sailplanes? This turbulates the flow, helping it to stay attached though turbulent--less drag than detached flow.

Can you please post more pics showing other helmet mods, esp. those making the helmet quieter? Mine are always too noisy.

GasSavers_SD26 · 04-02-2008, 04:58 AM

Ear plugs work the best for quiet. That's what we wear when racing. Eliminated the high frequency sound of wind, but I can hear my engine, even mechanically, and other bike's I'm racing with behind me.

JanGeo · 04-02-2008, 05:57 AM

I ran with a Gibli helmit for year because it was totally smooth on the outside with a flush flip up visor. But I added a flap of soft vinyl under my chin between the helmit and my neck and taped it to the bottom leading edge and that totally quieted the helmit. Usually more padding under the ears and back of the neck to seal the helmit more is also good in cold weather.