R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 09-10-2009, 04:49 PM   #1171
Tech Champion
 
MikeXray's Avatar
 
Join Date: Oct 2006
Location: New York
Posts: 5,749
Trader Rating: 73 (100%+)
Default

Quote:
Originally Posted by liljohn1064 View Post
Definitely something else to check. I'll take a look.
The pics didn't show up when I was at work, but the arms look fine now that I can see them. I'm thinking your servo saver might be a bit big, but that could be the pic, I used a kimbrough med for that car.
__________________
Mike L. Awesomatixusa.com | TQWire.com | Islandraceway.com |JacksonRCracing.com | Horsham RC | Sweepracingusa.com
MikeXray is offline   Reply With Quote
Old 09-10-2009, 09:27 PM   #1172
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

http://teamcrc.com/crc/modules.php?n...od&prodID=1403

Use this 1/2 inch spacer to lower the battery top strap 1/4 inch. You need to readjust the center shock forward mount.

On the fifth body post, I use one almost always now. It helps prevent cracking of the wheel arches. It keeps the dam at constant height over the bumps. Yes it will help the slower classes. I put a .113 hole just forward of the big center lightening hole between the steering blocks. Countersink it from underneath with an 82 degree shaped stone on the Dremel or get the drill and countersink at Stranahan-RC.com

82 degree countersink

.113 drill bit



Shape a Dremel stone to countersink or buy the bit.


Here is a pic of a Gen X 10 chassis with the extra body post.

Note the lower arms can be sanded to increase steering link clearance. There is plenty of meat there.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-gen-x-10-dual-arm-front-end400pix003.jpg  
__________________
[email protected]
TeamCRC.com Mikes-HobbyShop.com

Last edited by John Stranahan; 09-11-2009 at 05:23 PM.
John Stranahan is offline   Reply With Quote
Old 09-10-2009, 09:41 PM   #1173
Tech Champion
 
liljohn1064's Avatar
 
Join Date: Sep 2008
Location: Deerfield, WI
Posts: 5,581
Trader Rating: 17 (100%+)
Default

Quote:
Originally Posted by Shawn68z View Post
instead of moving your servo around, I noticed that you have the links attached to the front of the servo saver. Move them to the rear of the servo saver, this will straighten them out as well. You may have a small clearance issue with the lower a-arms, but nothing a pocket knife cant solve.

Where are your washers on the front end? I run 2 back and 1 front.

Shawn.
I didn't run into a clearance problem until I flipped the studs to the back side. I solved it by moving the servo up the servo bracket. I run 2 to the back, 1 to the front for the washers.
__________________
John Higgins former student of The Ian Ruggles Negative Reinforcement Driving School. The "Team Principal".
liljohn1064 is offline   Reply With Quote
Old 09-11-2009, 11:09 PM   #1174
Tech Champion
 
liljohn1064's Avatar
 
Join Date: Sep 2008
Location: Deerfield, WI
Posts: 5,581
Trader Rating: 17 (100%+)
Default

I finally got it tested with the new TQ Booster and 1S. The roll out was very close at 62mm. I will probably drop it a couple of teeth and test again in the high 50s. The only odd thing it does is occasionally lift the inside rear wheel in a corner making the car do a snap spin. While practicing I knew when to expect it and drove through the issue. A guy at the shop says try heavier rear springs than the whites. Any recommendations?
__________________
John Higgins former student of The Ian Ruggles Negative Reinforcement Driving School. The "Team Principal".
liljohn1064 is offline   Reply With Quote
Old 09-12-2009, 09:26 AM   #1175
Tech Adept
 
Join Date: Jan 2009
Location: colorado
Posts: 192
Send a message via Skype™ to slotracer577
Default

I have been having the same issue with snap spins as the traction comes up. Right now I think the front is too soft and I am getting too much weight transfer. Going to try stiffer front springs tonight to see if I can cure it. will let you know how it goes.

John
slotracer577 is offline   Reply With Quote
Old 09-12-2009, 06:37 PM   #1176
Tech Champion
 
liljohn1064's Avatar
 
Join Date: Sep 2008
Location: Deerfield, WI
Posts: 5,581
Trader Rating: 17 (100%+)
Default

Quote:
Originally Posted by slotracer577 View Post
I have been having the same issue with snap spins as the traction comes up. Right now I think the front is too soft and I am getting too much weight transfer. Going to try stiffer front springs tonight to see if I can cure it. will let you know how it goes.

John
That's a good idea. With such high traction I could almost induce a little push just to see how it affects the weight transfer.
__________________
John Higgins former student of The Ian Ruggles Negative Reinforcement Driving School. The "Team Principal".
liljohn1064 is offline   Reply With Quote
Old 09-12-2009, 09:40 PM   #1177
Tech Addict
 
Join Date: Jan 2008
Posts: 706
Trader Rating: 6 (100%+)
Default

Quote:
Originally Posted by slotracer577 View Post
I have been having the same issue with snap spins as the traction comes up. Right now I think the front is too soft and I am getting too much weight transfer. Going to try stiffer front springs tonight to see if I can cure it. will let you know how it goes.

John
I run green fronts springs, and red side springs. I normally put a full extra turn on the side springs once they have made contact with the pod plate. I found the little bit extra tension helps keep the car more stable. I also have screws put into the bottom of the tweak plate to limit the amount of twist allowed. Also,I find the damper tubes have to be filled every 2 races, and I normally use the crc "heavy" tube lube.

Shawn.
Shawn68z is offline   Reply With Quote
Old 09-13-2009, 10:09 AM   #1178
Tech Adept
 
Join Date: Jan 2009
Location: colorado
Posts: 192
Send a message via Skype™ to slotracer577
Default

Was running white springs, had to go all the way up to purple to get a slight push. I like my car to have a slight push vs right on the edge so you have some margin before it spins out. Had a black front which I think was not hard enough. Going to go harder on the tire and see if I can go back down on springs.

Since I was running oval, I had a RF all the way left for some rear steer. Made the car really turn, but had to take it all out along with the harder springs to keep the car working. Even had to go stiffer through the night as more rubber got laid down. Normally I would just not apply traction compound, but if you dont the tires glaze over in less than a run.

John
slotracer577 is offline   Reply With Quote
Old 09-13-2009, 06:15 PM   #1179
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Lifting rear tire. I have never had this, but if I did, I would move some weight back. That's one purpose of those nerf wings, there is a place for that weight now. The snap spins may be caused by torque steer of the highly loaded outside rear (especially if the inside rear is lifting). This is helped by moving weight back.

I have had to mess with the steering links and servo on this prototype car in the pics so I thought I would discuss two topics that we have talked about recently in messing with the links.

Ackerman-Ackerman lets the inside front tire turn a tighter radius than the outside tire. Ackerman in a pan car is produced by the angled steering arms that rotate the steering block and front axle. Ideally we would have steering links that push straight in and out to get perfect ackerman Ala the TC3. On the Pan car the best we can do is to align the links perpendicular to the long axis of the car. This gives the most ackerman. Moving the servo forward or backward from this position reduces ackerman. We have angled steering links. The car may or may not benefit from this. Try it both ways. On asphalt I am always perpendicular if possible.

Bump Steer- Bump steer is the movement of the steering axle as the suspension goes up into bump. Ideally we want no bump steer or a slight bump steer out. Bump steer out means as you push the suspession up the front wheel angles out just a little. My Pan cars and touring cars generally have a little bump steer out. What this does is give the car a forgiving cornering attitude. If you hit a high traction patch the car rolls a little more, the steering goes out just a little to reduce bite. This keeps the car stable and keeps it from spinning out. On a pan check this by removing the front tire. Push the kingpin up with your finger. Watch the front axle. You want it not to steer or to steer a little out as you push up. I can't usually achieve 0 bump steer on a pan as the ball needs to be middle of the steering arm. Adjust this by moving the ball up on spacers or the inner end up or down on the servo saver. In the pic below I am one hole up on the medium Hitec Servo saver.

I just finished the prototype 200 mm Dual A-arm Front Suspension. Arms are moved inward 13 mm on both sides compared to the wide pan car. I was able to achieve good ackerman and slight bumpsteer out. When you have no bump steer or slight bump steer out you will find that your steering links point to the instant centers on the inboard side. It was found early on that having the servo angled was a way to approximate this without making extra linkage and complexity. We tried running our servos flat and feeding links out of the top. For me this involved using pretty tall spacer stacks on the steering arms ball pivot to reduce mad bumpsteer. This made the steering less precise so I am back as most companies are to an angled servo. Some of the 1/12 guys ran on carpet with servos flat for a while. I don't know if this setup stuck or not.

JS Pro 200
First Pics: Dual A-arm Front End on 200 mm Prototype

Here are the first pictures of the Dual A-arm Front End on a 200 mm Prototype using all Production parts from Stranahan-RC/Powell (PRC). The graphite top plate and lower pivoting arm extension are a first of, masterfully CNC machined by Doug Powell. It will require only a slight caster adjustment for full production. The extensions will only need a slight servo clearance flat included.

Ride height and travel are good. The Springs are custom wound for this car from .045 inch diameter Satin Finish Stailess Steel Spring Wire.

Ackerman and bump steer came out good, with one very thin .016 inch thick washer under the Aluminum servo mounts to raise them.

The last pictures are of the 3-link rear end with all production parts. A few small mods will be needed before full production. This is the first Heavy Duty Pod Bottom Plate.

Anyway, we have not been idle but suspension kits are not quite for sale yet. Please refer any questions about orders or stock in hand to Pm or e-mail.

Capt Slow- Note there is a divot in both the 200 mm and wide pan top plates to allow for the extra front body post (rear center of hood) that we talked about.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-200-mm-pan.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-back-view-200-mm-pan..jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-3-link-rear-end-200-mm-pan-001.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-3-link-rear-end-rear-quarter-view-200mm.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-js-pro-200.jpg  

__________________
[email protected]
TeamCRC.com Mikes-HobbyShop.com

Last edited by John Stranahan; 09-13-2009 at 07:35 PM.
John Stranahan is offline   Reply With Quote
Old 09-14-2009, 10:45 AM   #1180
Tech Elite
 
JayL's Avatar
R/C Tech Elite Subscriber
 
Join Date: Mar 2006
Location: Ca
Posts: 2,880
Default

John: could you list a few general things that would help mid corner push. Initial is great just mid.
Thanks
JayL is offline   Reply With Quote
Old 09-14-2009, 10:48 AM   #1181
Tech Champion
 
liljohn1064's Avatar
 
Join Date: Sep 2008
Location: Deerfield, WI
Posts: 5,581
Trader Rating: 17 (100%+)
Default

Quote:
Originally Posted by Shawn68z View Post
I run green fronts springs, and red side springs. I normally put a full extra turn on the side springs once they have made contact with the pod plate. I found the little bit extra tension helps keep the car more stable. I also have screws put into the bottom of the tweak plate to limit the amount of twist allowed. Also,I find the damper tubes have to be filled every 2 races, and I normally use the crc "heavy" tube lube.

Shawn.
I'm still going to try your suggestions, but I know my tubes need to be relubed and the back springs were not preloaded enough.
__________________
John Higgins former student of The Ian Ruggles Negative Reinforcement Driving School. The "Team Principal".
liljohn1064 is offline   Reply With Quote
Old 09-14-2009, 10:56 AM   #1182
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

JayL-To help a mid corner push.
More caster (Typically I use 4-6 degrees). This is most helpful mid corner and takes away a little corner entry steering traction.
Trailing Axles (this adds more caster still)
Softer front spring (this can cause chassis scraping on high speed turns)so don't go too soft. If you can't go softer in front go a little stiffer in the rear side springs (tweak springs). I am red to purple usually outdoors in front and white or red in the back.
Softer front tires. If you are on purples try the CRC spec front.
__________________
[email protected]
TeamCRC.com Mikes-HobbyShop.com

Last edited by John Stranahan; 09-15-2009 at 12:03 AM.
John Stranahan is offline   Reply With Quote
Old 09-14-2009, 09:47 PM   #1183
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Drilling Template for Gen X 10 and other pan cars
Here is a template that can be used to center that third front body post in a Gen X 10. This is what you do. Strip the steering off the chassis. Cut out the suspension mounting holes, the outer four holes, with your X-acto knife. Bolt it to the top of the chassis with button head screws. Center punch that center hole. Remove the template. Use a #2 center drill to start the hole. Then through drill with a .113 inch drill. Now countersink from the bottom with your shaped Dremel stone (see the pic above) or use an 82 degree countersink.

The trick is to get the template to come out 1:1 scale. On my Deskjet, I unselect the fit to page box and select 1:1 scale. It prints very accurately to scale from the CAD. I will include this deskjet print which happens to be within .001 inch on dimensions with the Dual A-arm front ends intended for 200 mm cars. (When using a scan in autocad I routinely end up using .997:1 scale to get the correct size pic.) See printing hints below.

If you are on the oval and would like to do some preliminary checking to see if it the dual A-arm front end will fit your chassis, all you need is graphite under the inner set of four holes. If your chassis is a go, then please list it on this thread, or send me a PM, and I will compile of list of chassis that can be modified.

I plan to make a drilling jig with hardened steel drilling bushings to accurately and quickly do this drilling job for you if desired. You will just need to mail that chassis in a big envelope with one carboard layer to protect it from folding). I will also have new chasses available with the mods already made on it. Additional cost will be only $10 if the jig works out. A fifth body post hole will be provided. Im tinkering with printing this image. If yours is not to scale see if a scale setting on your printer or copier will correct it. If not request a free copy of the drill template (additional postage charge for international requests) from [email protected] (tinker with the size in a photo viewer program)

On advice I changed the pic to a .pdf. When you print it landscape, check the 1.4 inch dimenison with your dial caliper. Mine was perfectly to scale.

Note any modified chassis can be returned to stock and run the stock Prostrut front suspension with only an upgrade in fasteners to the black oxide coated alloy steel flat head screws. It is plenty stiff, well tested by myself in a very similar arrangement, and the steel screws more than double the clamping force available from the original aluminum.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-drill-template-200-mm-car.jpg  
Attached Files
File Type: pdf Chassis Drilling Jig Measures to be Published-Model.pdf (173.4 KB, 94 views)
__________________
[email protected]
TeamCRC.com Mikes-HobbyShop.com

Last edited by John Stranahan; 09-15-2009 at 07:34 PM.
John Stranahan is offline   Reply With Quote
Old 09-15-2009, 03:51 PM   #1184
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Wide Pan Nerf Wings

This new product just came into production. It is similar to the Nerfwings on the 200 mm car, just wider. You may have seen the handmade prototypes earlier. This one is fully CNC machined by Doug Powel. The goal of the nerf wing is to reduce damage to axle and pod in a severe crash to the side. It also makes a place where you can put electronics and ballast if you so desire. Note the 50-50 front to back weight split does not apply to 2-w-drive pan cars. You should have some extra in the back. 6 cell NiMH guys used to prefer either a 4 x 2 arrangement of cells or 3 x 3 side by side in the back. This is preloading the rear for better forward traction, fewer snap spins. With a LiPo stick pack you can approximate this balance by putting electronics and ballast rearward.

If you want a pair of these wide pan Nerfwings early, you may be able to coax a pair from [email protected]. Price should only be a bit higher than the 200 mm Nerf wings. There is more graphite used.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-wide-pan-nerf-wings-001.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-wide-pan-nerf-wings-002.jpg  
__________________
[email protected]
TeamCRC.com Mikes-HobbyShop.com

Last edited by John Stranahan; 09-15-2009 at 07:47 PM.
John Stranahan is offline   Reply With Quote
Old 09-15-2009, 07:23 PM   #1185
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Drilling Template

I was told it might be helpful to post the drilling template in a .pdf file to insure better scaling. Here is a copy. I can also e-mail the .dwg CAD file by request.

My download and print on a deskjet came out perfectly to scale. It's a go.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-drill-template-200-mm-car.jpg  
Attached Files
File Type: pdf Chassis Drilling Jig Measures to be Published-Model.pdf (173.4 KB, 65 views)
__________________
[email protected]
TeamCRC.com Mikes-HobbyShop.com

Last edited by John Stranahan; 09-15-2009 at 07:33 PM.
John Stranahan is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks John Stranahan Oval, Larger Scales and More 0 05-25-2008 11:48 AM
Electric 10th scale sell-off (T4 team, Sphere, Transponder, LiPo, Brushless...) floatch R/C Items: For Sale/Trade 27 03-14-2008 04:37 AM
Battle Brushless Sensorless Mamba Max : Trinity N80 VS CM 36 moumerico Electric Off-Road 3 04-12-2007 03:18 PM
Battle of the EPs (On or Off Road)! marzin Singapore R/C Racers 4 09-22-2005 09:27 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 12:38 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net