58 replies to this topic

[Tim Neja]

I KNEW you'd have a logic for it!! Just didn't see it!! Yeah--the mtng points would be farther back for the body!! I'll just trim them off and put them where I want them! 

[Larry Labounty]

Jim .Do you think it better to cut off the stock flagg holder ? What guide lead would you like to see ?

Larry

[JimF]

Hey Larry:

 

Keep in mind that up here in NorCal we run on a variety of tracks and none of them are Gerding Kings. On a Gerding, I might well leave it alone. For our mix of flattish Kings, Hillclimbs, the Purple Angel and our assorted flat tracks, I'd be leaning toward .950" or even 1.00". With the way I built this one, I don't think I could cut off the stock guide tongue and have any meat left at the end of the slot where the fork tubes go.

 

I think what I'll have to do is drop out the hinge tubes and replace them with shorter ones (or) just push the tubes further back on the forks by maybe 1/4" or so. Then, I could fabricate a new guide tongue maybe .500-.600 wide or so in order to bridge the front part of the hinge tube slot.  

[Rick]

Jim,

 

Before you cut, I can send you a full length guide support and you can slot to your needs and get as long as you want, I think?

 

 

 

[JimF]

Yup, that'd do 'er. Thanks.

[Cheater]

Because of the information and quality of this thread, it has been moved into the Tech How-Tos & Tutorials subforum.

[JimF]

These have been built but sitting for quite a while but have yet to run. This is my first available moment to talk about 'em.

 

Here is the next iteration of the GVP concept. This one is built with the flatter tracks and variable conditions of NorCal in mind. Aside from details, there are a few significant differences between this version and the first one. The main frame rails are 2 x .055 unsoldered, the guide lead is longer (.950), and the pans are solid instead of windowed. For this build, Rick supplied the noseplate without the coining of the guide tongue and he provided the wide, steel guide tongue. You can see from the bottom view, that all I had to do was cut off the very front of the flat guide brass tongue and solder on the steel one. Then I was able to notch the steel and still have plenty of meat left surrounding the various cutouts. The hinge rods are .055 in 3/32 and the crosspiece is .047 running through 3/32. This is sort of a combination shaker and hinge setup. This frame runs about 104 gr. all up but sans the body.

 

 

 

Bottom view of the GVP kit along with another one that I cobbled up from other parts. The other one is a JK noseplate cut up and notched for the forks. This one uses .055 forks and single .055 main rails. The rear weight blocks are 3 gr. each and this frame all up except for body runs 97.5 gr. On this one, the forks are soldered solid in front with no hinge tubes.

 

 

 

Both of these frames have a flex limiter at the crux of the fork rails (arrows). I think that this helps in case the car has wheel hop on hard acceleration. These have yet to be run but hopefully will be tomorrow (Sunday) @ Fast Track Hobbies. We'll see how these both run on the technical compound radius turns of the Purple Angel track.

 

 

 

 

 

 

 

 

[JimF]

Here's a quick track test update. I ran both these cars Sunday on the Purple Angel @ Fast Track Hobbies in Rocklin. The test track was the 165 ft Purple Angel. This is a unique (I think) track that is mostly flat with a number of interconnected turns. This track runs faster lap times than any of our tracks except for the most highly banked King. Surprisingly, the light, fixed fork car was faster than the GVP which felt a little loose. I ran through the litany of tires and the light car ran best with Kelly Retros or JK 8713P. This was a surprise b/c usually I run treateds here and almost never get Retros to work. The GVP felt like it had the potential but I couldn't get enough grip with JKs and didn't have another set of retros with me.

 

Next test later this week will be a more serious attempt with the GVP with some bitier tires. I also have a suspicion that the solid forks on the light car may be a contributing factor to the car being slightly tighter so I may also try a second flex limiter near the front of the GVP forks. It also could be that the doubled main rails on the GVP make the car just enough stiffer that it won't get the grip that the other one does regardless.

[Tim Neja]

Always great pictures and explanations on your builds Jim!!! CYA down at The Cave soon!! Thanks for sharing!!