Fenders

[microbrush]

I am new to fenders and am trying to figure out why some fenders have such a wide cut-out on the bottom of the fenders. It would seem that the fender would be better to be as wide as possible without touching/interfering with the track. People use such tight gaps, it seems to me, that a smaller cutout would be more beneficial. What am I missing?

Thank you to everyone on this site for all of the valuable information!

 

[561 racing]

If I'm not mistaken the wide cut out is to prevent it from rubbing on the rail and slowing the car down.

 

[ngyoung]

Not really sure what you're asking. There is a notch behind the fender at the bottom that is for clearing the rail. What do you mean by a smaller cut out. There are some scout cars that have bulkier fenders but for the most part the fast guys are using pretty streamlined and just barely cover the width of the wheel.

 

[BulldogRacing]

I had larger fenders and when I switched to GEE, my times got faster.

 

[microbrush]

Thanks Bulldog. It IS the gee fenders I am wondering about. This is the view of the bottom of the fenders. The top of the fender is the width of the wheel. The bottom half seems to cover less than half of the wheel; therefore, the fender is covering less than 3/4 of the wheel. On the website it states: The underside relief cut is completed and done in the right manner. I am just trying to understand why it does not cover more of the wheel on the bottom. I know that these fenders do aid in a faster time and are easy to add.

Also, just wondering what the fastest racers use/do if your race allows fenders. Again, I have learned a lot from this site. We did CA glue the fenders between two small strips of roughened metal tape; one piece on the gee fender and one piece on the wood body, creating a "sandwich effect". This should aid in getting them off easily and able to reuse in the future.

 

[HMH Racing]

Micro,
That's similar to how we mount our fenders. Also not sure when your race is, but if you have time you may want to cut the extra wood that is sticking out in the back car off and glue it to the front. It looks like there is a lot of wood between your rear axle and the back of the car.

 

[microbrush]

HMH- Glad to know we placed the fenders in the correct orientation. The wood you see is an uncut block that is sitting on the top of the silver bullet. The car ends where the foil tape ends. About 5/8 from the back of the car if I recall correctly. I am glad I cropped out my linemen's pliers. I was temped to leave them in and say that is what I use to tune the DFW.

We made it through pack and districts, just trying to improve for council. I do not think that the fenders need improving, probably better wheel and axle prep.

It is just my little brain does not understand the bottom cut. I am just trying to understand/ learn how it works.

Any thoughts?

 

[Mr Chips Racing]

Over the years fenders of all types have been tested. I can tell you the reason the Gee Fenders work so well and why they don't cover the bottom.

1- relief cut so not to drag on the rail
2- these were created in a wind tunnel with every imaginable configuration.
3- the ones used today have just proven the most aerodynamic.

 

[HMH Racing]

Yes, good axle and wheel prep is important along with a very good drill job on the rears. Have you watched DD4H's dvd on the oil process? If not it is a good investment, lots of info, even if you have to run graphite.

 

[bracketracer]

It is just my little brain does not understand the bottom cut. I am just trying to understand/ learn how it works.

Any thoughts?

Have you ever blown on a pinwheel? What happens when you blow sideways across the bottom and then blow across the top while it's still spinning? It stops and goes the other way, right? Now look at how the air hits the wheel with that fender. What do you think that does for you? It keeps you from "blowing on the top", right? Now what else does that angle underneath do for you?

 

[microbrush]

Have you ever blown on a pinwheel? What happens when you blow sideways across the bottom and then blow across the top while it's still spinning? It stops and goes the other way, right? Now look at how the air hits the wheel with that fender. What do you think that does for you? It keeps you from "blowing on the top", right? Now what else does that angle underneath do for you?

That's very interesting. I will look at it closer with that in mind. This forum is great!

No, I don't have the DD DVD. I should place another order. Most of what I know is from this site and the little instructions that come with the product. It sounds like most people can take new "nuggets" from the DVD every time they watch it.

I am a typical male, and so usually start assembling first and then look to the instructions if needed. It looks like some instructions may be needed/helpful.

 

[Bullet]

Microbrush,

What's that in your avatar? Is that a "microbrush"? is there something behind those you could share? /images/boards/smilies/smile.gif

 

[microbrush]

Microbrush,

What's that in your avatar? Is that a "microbrush"? is there something behind those you could share? /images/boards/smilies/smile.gif

It is a Microbrush

. That is literally the name of the brush. I use them for work. It looks like some stores may carry them: http://www.microbrush.com/hobby/howtobuy/area.asp I don't know if they are the exact same as I get.

They cost me about 10 cents a piece. They work well for adding polish/oil in the bore. They are lint free. The regular size work the best. Think that blowing compressed air cleans out the bore well after a fluffy cleaner--- think again. These little guys help get all the dust out. Look under 20X magnification and it is scary. It is also scary how rough even going up to a 12000 micromesh polish is on the axle. I was looking under 3.5X magnification for most of the work and thought it looked great. At 20X it is terrible. I do like the Micro details.

I like Fumbles axle polishing pic's: http://www.pinewoodderbyonline.com/post/axle-polishing-pics-7330403?pid=1286543902#post1286543902

I would like to post some 20X pic's if I get the time and capability to take a photo.

 

[HMH Racing]

I get mine at Hobby Lobby. They are by the Testors paint at the store near me.

 

[down4derby]

I use a micro brush also. I don't know where I got it but it says binaca on it so I assume it's for cleaning teeth or braces. I use it to remove any loose plastic leftover from lathing. It removes things a pipe cleaner can't preventing you from embedding it in the bore when you run a swab through it.

 

[Bullet]

Wow...cool! I was sorta just poking fun, but sounds interesting, need to check them out! /images/boards/smilies/smile.gif Would be good to get the initial "stuff" out of the wheel bore before first polish, as mentioned the lathing debris. I forgot to do this one time and ruined a set of $40 wheels....would be a good investment.

 

[derby freak]

sole purpose of the cutout is as others mentioned......it is to clear the center rail...... keep your fenders as small as possible and still be able to serve their purpose