Gravity class insights

Talk forum for HO scale slot cars. 1/87 and 1/64 scale.

Moderator: The Law

Re: Gravity class insights

Postby jpennington » Tue Jan 03, 2017 3:53 pm

Landshark hinge car

Christmas came late in the form of a Landshark hinge car last week from Al Thurman. I own two other Landshark , one that finished 1st at the nats exisbition race in 2011 and one that finished 2nd at the gravity race at the nats in 2014, so they have been good cars for me. Anyone hanging out with me in August 2016 will know I had time for one preseason build and what was it gong to be, a Z-rail or a hinge car? The Z-rail won out, but I still wanted a hinge car, so thank you Al.

My initial drive out of the box was quiet pleasant. It was an easy to drive, well balanced car, that turned respectful times. At this point I have not done the weight suggestions that Al made. I plan to do that and perhaps some modular changes, but no cutting or soldering - I need to learn the wisdom of this car. I will keep you posted there in.

Image
Car with questionable spoiler

Image

Image

Image

Image
Note the bend up at the front end. This allows additional wiper clearance and less pressure on them setting up the front wheels to do there job more effectively.

Nice work Al. I look forward to getting this car raced!

Joel
jpennington
POS Posting Professional
 
Posts: 265
Joined: Wed Jun 22, 2011 8:52 pm

Re: Gravity class insights

Postby gregw » Sat Jan 07, 2017 4:15 pm

Development on the Pro Mod AFX Gravity (AFX chassis only mods for removable brass stuff) has been on hold but will soon ramp up.

Joel, is there some specific rules you have for the Gravity class? Has there been some specs made for aerodynamic stuff such as spoilers, side dams, etc?
User avatar
gregw
POS Posting Professional
 
Posts: 1497
Joined: Fri Nov 28, 2003 6:40 pm
Location: Phoenix Arizona (AHORA HOPAC)

Re: Gravity class insights

Postby akaHOllywood » Sat Jan 07, 2017 5:32 pm

Big wing-car style air dams aren't allowed. BTW, Gravity Class rules are in the HOPRA rulebook, which you can download from the HOPRA website.
akaHOllywood
POS Posting Professional
 
Posts: 1606
Joined: Fri May 28, 2004 12:57 pm

Re: Gravity class insights

Postby John Reimels » Mon Jan 09, 2017 1:37 pm

While not quite an AFX Brass Class set of rules, for Gravity Racing of New England (GRoNE) we're trying to generate interest in a T-Jet Brass Pan class. The ideal is to keep the class fairly simple using off the shelf parts wherever possible (no rewound armatures; bolt on brass pan; ceramic magnets, etc). I'm in the process of building up 4 IROC cars using our proposed rules to determine the viability of the class We're hoping this will appeal to the T-Jet racers in the area and help generate interest in our events. Below is a draft of the rules...

Brass Pan T-Jets
Draft 4.0
December 22, 2016

The intent of this class is to create cars similar to those being created in the late 60s before the start of the brass war period. The class is wide open as long as it’s powered by a pancake armature in a T-Jet style chassis.

1. Width:
a. The complete car must freely pass through a standard 1.3125 (1 and 5/16) HO tech block including front wheels at their full extension.

2. Chassis and Gear Plate:
a. Only the Aurora, Model Motoring, Johnny Lightning/AW, and DASH T-Jet style chassis are legal.
b. Weight pans are allowed provided they are attached to the chassis via the front and rear body mounting holes and are readily removed
c. No floating pans
d. Chassis modifications are allowed but overall dimensions and architecture must be retained including the thickness of the chassis beneath the magnets.
e. Separate bearing and bushings are not allowed, stock armature and axle holes in the chassis and top plate must be utilized in their original location
f. Electrics can be soldered and shunted, but must be in original configuration

3. Gears:
a. 14-tooth armature pinion, 24-tooth idler and driven gears.
b. Rear end gears: pinion (9, 12, 14)/crown (15 tooth)
4. Armature:
a. Any stock arm that the average resistance of the three poles is 4.00 ohms or greater
b. Armature may be balance and trued
c. No other modifications allowed

5. Motor Magnets:
a. Ceramic only.
b. Magnets may be shimmed with non-magnetic material

6. Brushes:
a. Any carbon based brush may be used.
b. Separate brush springs are not allowed, tension must be generated by the standard steel metal cantilever spring

6. Pickup Shoes:
a. Any shoe can be used in the original configuration.
b. Wipers are not allowed

7. Axles (Front and Rear):
a. No restrictions

8. Wheels (Front and Rear):
a. Front - No Restrictions
b. Rear – Slip-on tires only

9. Pick Up Springs:
a. No restrictions

10. Guide Pin:
a. No restrictions other than only one allowed


11. Bodies:
a. Bodies can be injected molded, cast resin or vacuum formed

12. Track Power:
a. Races shall be run at 20.0 volts +/- 0.25 volts.
John Reimels
John Reimels
POS Rookie
 
Posts: 18
Joined: Sat Aug 08, 2009 3:34 pm
Location: Scituate, MA

Re: Gravity class insights

Postby chaparrAL » Mon Jan 09, 2017 10:52 pm

Cool John!
Let me know if you need some more Tjet pans.
The beauty of this is we can develop these cars together using the expertise and experience of many Frey class racers. Put some silicone coated sponge tire on the back and you are ready to race at the HOPRA Nats. One with a Dash chassis that I worked over finished second in the first Midwest Series Gravity race at Lucky Bobs driven by Bill Armour.
:)
User avatar
chaparrAL
POS Posting Professional
 
Posts: 804
Joined: Fri Nov 07, 2008 4:00 pm
Location: The Compound in the Desert

Re: Gravity class insights

Postby John Reimels » Tue Jan 10, 2017 12:26 pm

Thanks Al. I forgot to mention in my original post that I'm using your brass pan! Duh!!! The idea behind the slip-on rear tire rule is two-fold. I know a lot of time and effort went into developing these tires a few years ago; unfortunately they just weren't competitive with the silicone / sponge tires so a lot of folks have them sitting around unused. Given the horsepower of a 4 - 5 ohm arm allowed in these rules, I thought the slip-on tires might be more durable. Hence the rule... If they don't seem to handle right, we can change the rule accordingly. Let's see what works best.

John
John Reimels
John Reimels
POS Rookie
 
Posts: 18
Joined: Sat Aug 08, 2009 3:34 pm
Location: Scituate, MA

Re: Gravity class insights

Postby jpennington » Mon Jan 16, 2017 5:13 pm

AFX vs ________ Race three:

The third race of this challenge took place January 14th on Jim Rumph’s Max track as part of our MWS. Here are the top four results in Gravity:

1st Trevor M. 350 laps AFX

2nd Rick DeRosa 345 laps AFX

3rd Joel Pennington 330 laps Sidewinder

4th Bill Evans 328 laps Sidewinder

Honorable mention to Jim Rumph – high qualifier with an AFX but had an early outage with car problems. No doubt he was a top three guy.

Early in practice it became apparent to me that the advantage was to the AFX platform on the slicker Max track surface. The AFX would have been my race car choice, but I had committed it to be driven by Rick DeRosa as part of this four race/four driver challenge. Rick did a fine drive with it, but had some minor problems on two lanes of the six lanes on the track. Trevor won his first Midwest race with a year old AFX, on track he drives well – congratulations.

You can see by the lap disparity that the advantage was substantial for the AFX platform. This was mainly seen in the consistency of the totals across the lanes.


The non-AFXs turned similar lap times and totals, but did not perform this across all six lanes. This was the seventh race on the car I was running; it won its first six races and set new lap total records at each of those races, so it was no slouch.

Moral to the story so far is choice in the box is good!



Joel
jpennington
POS Posting Professional
 
Posts: 265
Joined: Wed Jun 22, 2011 8:52 pm

Re: Gravity class insights

Postby HoBro » Wed Jan 25, 2017 6:50 pm

Howdy folks,

Newbie here .... looking for some information from you builders

Anyone have a source for metallic pinion gears for these little beasts? (1MM shaft)

Thanks in advance for any assistance!

-Jeff
HoBro
POS Lurker
 
Posts: 9
Joined: Thu Dec 01, 2016 1:00 am

Re: Gravity class insights

Postby jpennington » Fri Jan 27, 2017 12:05 pm

Jeff, I started out in Gravity using metal pinion gear. It was a 7th 64 pitch brass gear that I made for Tony P from a pinion rod. Tony supplied that pinion rod, but I have never been able to locate it since. The hole in that gear was .059 inches, so I had to sleeve it for a 1mm shaft. If you are prepared to sleeve gears the whole .059 gear world is open to you. Micro group makes the stainless steel tubing in the sizes you need to make this easy.

I prefer and currently use a modified plastic Life like 7th pinion. It has a 1mm hole, and all I do is to adjust its length and Locite it into place. They are Lighter and smoother than the metal ones.

If you are really wanting a metal gear I will discuss your fabrication opitions. I have our unlimited car pinion gear blanks hobbed out of O-1 steel.

Joel
jpennington
POS Posting Professional
 
Posts: 265
Joined: Wed Jun 22, 2011 8:52 pm

Re: Gravity class insights

Postby RT-HO » Fri Jan 27, 2017 4:17 pm

I have a few CNC 8 tooth brass gears that I made for that size shaft.
They are a little thicker than a T-Jet gear.
I made them for a mini motor sidewinder project.
I'm not using them - $8.00 each plus shipping.
RT-HO
POS Rookie
 
Posts: 11
Joined: Wed Apr 28, 2010 11:06 pm

Re: Gravity class insights

Postby HoBro » Mon Jan 30, 2017 8:08 pm

Thanks guys. I tried the sleeving route....and it worked, but let's just say it was problematic. I have since opted to go with LL smaller T pinions. I got a bit ahead of myself when placing the order, and ordered non T pinions (standard size shaft). I plead the fifth, as I was blinded by my quest for speed.
:-)

-Jeff
HoBro
POS Lurker
 
Posts: 9
Joined: Thu Dec 01, 2016 1:00 am

Re: Gravity class insights

Postby jpennington » Mon Feb 27, 2017 4:02 pm

The February 18th Midwest Series race was won by Scott Terry with a brand new build! The design was a center hinge car based on his anglewinder design. This is the first center hinge HO car I am aware of built outside of the ranks of Al Thurman - Al has been on these things for more than a year.

I drove Scott's car pre race and you immediately knew you were driving a well balanced good handling car.

The fundamentals beyond the chassis were pretty much orthodox for Scott.


Imageg

Image

Image

I plan to write soon on how I will continue to post to the gravity community.

Joel
jpennington
POS Posting Professional
 
Posts: 265
Joined: Wed Jun 22, 2011 8:52 pm

Re: Gravity class insights

Postby LDThomas » Tue Feb 28, 2017 10:45 am

That is a very nice looking car. Well done, Scott.
LDThomas
POS Posting Professional
 
Posts: 1767
Joined: Wed Jun 02, 2004 2:26 pm
Location: Beatrice, Nebraska

Re: Gravity class insights

Postby slotking » Wed Mar 01, 2017 10:24 pm

very nice work on that car
very impressive
User avatar
slotking
POS Posting Professional
 
Posts: 3380
Joined: Fri Jun 04, 2004 1:30 am
Location: Rochester, NY

Previous

Return to HO Slot Car Planet

Who is online

Users browsing this forum: No registered users and 11 guests

cron