|
Post by roosclan on Dec 27, 2008 20:44:23 GMT -6
My boys' pack and district require the original slots to be used (no extended wheelbase and no newly drilled holes). I have heard about cutting off about .3" off the back of the block and gluing it to the front to keep the 7" length, and we did that with one of my boys' cars last year. My question is this: Is it really necessary to glue the cut-off part back onto the car? - Keeping it off will allow more weight to be placed where it will do the most good -- at COM. It will still meet 5oz. and less of it will be in front of the front wheel.
- Since the stock wheelbase will not change, leaving it off might improve the balance (adding it to the front will just increase the amount of weight that is forward of the front wheels)
- It will allow for "tail pipes" or "rocket engines" or whatnot to stick out the back and still meet the 7" requirement if the scout so desires it (and I think my Tiger wants them).
- We will be using the Pro-Body Jig to lower the body, and I am uncertain if adding the extra length to the front of the car would cause the nose to hit the track at the transition. With the standard Pro Body Tool, it's OK.
I can't find any reason to put the cut-off part back onto the block, so if anyone can point out what I'm missing, I would be very grateful!
|
|
|
Post by ProQuest on Dec 27, 2008 21:12:47 GMT -6
Hey Roosclan,
Removing .3 inches from the rear of the car and adding it to the front accomplishes the EXACT same thing as moving the wheelbase and com back .3 inches. For example: Assume you are using a standard BSA block with the rear axle slot 6.0625" from the front of the block. Now assume that your com is exactly 1" in front of the rear axles. Therefore, your com is exactly 5.0625" from the front of the car, which in turn places it the same distance behind the starting pin when it is placed on the track. Now assume that you cut off .3" from the rear end of the car and glue it to the front of the car. Now your com is 5.3625" behind the pin. Having your com farther behind the starting pin translates into more potential energy, and ultimately more speed. Whether you should do this or not is your call. But that would be the reason to do it.
Not sure I explained that clearly. I'd be happy to clarify.
Steve H.
|
|
|
Post by roosclan on Dec 27, 2008 21:31:10 GMT -6
Hey Roosclan, Removing .3 inches from the rear of the car and adding it to the front accomplishes the EXACT same thing as moving the wheelbase and com back .3 inches. For example: Assume you are using a standard BSA block with the rear axle slot 6.0625" from the front of the block. Now assume that your com is exactly 1" in front of the rear axles. Therefore, your com is exactly 5.0625" from the front of the car, which in turn places it the same distance behind the starting pin when it is placed on the track. Now assume that you cut off .3" from the rear end of the car and glue it to the front of the car. Now your com is 5.3625" behind the pin. Having your com farther behind the starting pin translates into more potential energy, and ultimately more speed. Whether you should do this or not is your call. But that would be the reason to do it. Not sure I explained that clearly. I'd be happy to clarify. Steve H. That makes perfect sense! I knew there was something I was missing, but I just couldn't place it. My only concern now is whether or not the nose will hit the track at the transition (42' Best Track) since we will be using the Pro Body Jig to lower the body of the car. If so, then we'll have to redesign the nose of they boys' cars.
|
|
|
Post by ProQuest on Dec 27, 2008 23:53:47 GMT -6
Hey roosclan,
As long as the car has the requisite 3/8" center rail clearance, the nose will not hit the track at the transition or anywhere else. Nearly all of the Pure Stock class cars that race at WIRL and nearly all of the Limited class cars that run at PWDR are short wheelbase cars (4 3/8" or 4.5") built with the wheel base moved back as far as it can go. I have never heard of the nose of any car in either class hitting the track. If anyone out there has heard otherwise, I hope they will speak up.
Steve H.
|
|
Sappington R
Head in the Pine
"The Sappster" 10oz
Posts: 210
|
Post by Sappington R on Dec 29, 2008 8:56:08 GMT -6
Steve, I think I know what Roosclan is referring to when he describes the lower body to the track and the transition zone- the new Pro-Body Jig definitely drills a much more raised hole and therefore makes the car sit lower to the track- closer to the 3/8" minimum. Most of the cars that I've seen in the leagues have not been pushing the limit on bottom clearance so I can see his point. On a very sharp angle transition like a best track I can picture what he is describing when the front part of the car past the front wheels is VERY long & Low- it's possible to bottom out- the question is: How low can you go? One thing that I know for sure is that it won't matter on a gradual transition like the Piantedosi/Microwizard track- I've tried it already using the Pro-body jig.
Hope this helps.
Doug
|
|
Sappington R
Head in the Pine
"The Sappster" 10oz
Posts: 210
|
Post by Sappington R on Dec 29, 2008 8:58:28 GMT -6
One more thing to my last post: I would personally add the .3" of material back to the car front- it may not seem like a lot, but in a photo finish race- 1/16" or less is significant. Just ask any of the winners at this years Blue Grass Open.
|
|
|
Post by roosclan on Dec 29, 2008 22:36:52 GMT -6
Steve, I think I know what Roosclan is referring to when he describes the lower body to the track and the transition zone- the new Pro-Body Jig definitely drills a much more raised hole and therefore makes the car sit lower to the track- closer to the 3/8" minimum. Most of the cars that I've seen in the leagues have not been pushing the limit on bottom clearance so I can see his point. On a very sharp angle transition like a best track I can picture what he is describing when the front part of the car past the front wheels is VERY long & Low- it's possible to bottom out- the question is: How low can you go? One thing that I know for sure is that it won't matter on a gradual transition like the Piantedosi/Microwizard track- I've tried it already using the Pro-body jig. Hope this helps. Doug That's exactly what I'm saying. We cut and moved the .3" of wood last year, but we used a regular Pro Body Tool, so there was no issue with hitting the transition. With the body sitting lower, I don't know if it will be an issue this year. I wonder if anyone has tried the Jig with a Best Track yet, or if it will happen at the January WIRL race?
|
|
Sappington R
Head in the Pine
"The Sappster" 10oz
Posts: 210
|
Post by Sappington R on Dec 30, 2008 9:40:52 GMT -6
Roosclan, I did further research into your question on the new derbyworx pro-body jig regarding the lower bottom- according to the masked racer you are in the clear- go for it. Sapp
|
|
|
Post by roosclan on Dec 30, 2008 18:51:21 GMT -6
Roosclan, I did further research into your question on the new derbyworx pro-body jig regarding the lower bottom- according to the masked racer you are in the clear- go for it. Sapp That's good to hear!
|
|
beakerboysracing
Head in the Pine
You can pick your friends, you can pick your nose, but you can't flick your friends across the room.
Posts: 167
|
Post by beakerboysracing on Dec 30, 2008 19:39:14 GMT -6
Roosclan, I did further research into your question on the new derbyworx pro-body jig regarding the lower bottom- according to the masked racer you are in the clear- go for it. Sapp The pro body jig sets the ride height perfectly. I have a Go-No Go box from GPraceman, and a car drilled with the jig just barely clears. Just get your weight right, there is no room to add plates to the bottom. Have I mentioned how much I like the new pro body jig? It is way cool! ;D Scott Beakerboys
|
|
|
Post by clydesdale on Feb 12, 2012 15:51:40 GMT -6
Could you cut off more than .3? Will cutting off the back give a clear advantage over keeping the block intact?
|
|
|
Post by roosclan on Mar 4, 2012 10:20:39 GMT -6
Could you cut off more than .3? Will cutting off the back give a clear advantage over keeping the block intact? Cutting off more than that will cause the rear wheels to stick out past the end of the block, making the car longer than the 7" limit.
|
|
|
Post by rooneyhan on Jun 19, 2013 21:42:10 GMT -6
Nice to hear that you did.
|
|