Hi John, sorry for my comentary about the Calandra. We have to race here using rubber tires in the pan cars. The problem is that the track has a strech that is cement instead of asphalt and we have to paint it. This paint and foam are not very compatible unless you use sugar water or an aditive so we decided to buy those rubber tires with kevlar. Its the same for all the other classes including nitro. Another problem is that all the pan car chassis that uses the battery inline with the chassis tend to oversteer and lost rear traction exiting slow curves. The other cars including my modified RC10 uses adaptations for one 7.4 volt cell, transversaly in the chassis, more weight to the rear and also more body roll to the front that makes less agressive steering. We have a track in other city with high grip asphalt and the chassis with the battery inline are very fast and also you have to use foams because the rubber tires are destroyed easily.
During the last race in our ADOCARC track (youtube, adocarc pan car mayo 2011)I was in second place close to the guy in first, if you see and hear all the video you can hear a big crash because the first place eluded a sitting car, lost control in one of the fastest place and Carlos Di Vannna ran in to him with his Scimitar at such speed that destroyed the other guy chassis including bending his titanium rear axle. The Scimitar did not suffer anything because the angle of impact. The other car was an HPI pan car.(Out of production). José Álvarez. |
1 Attachment(s)
Thanks for the posts
1-12 Scale news, LRP SXX version 2 Things are going at a glacier pace here. I had planned to test the car with a SXX Stock Spec Speed control and a 3.0. I had the car running on the bench. The specs suggested a 4.5 on 2 cell LiPo was possible. I thought maybe a 3.0 on 1 cell might be handled. It spun the tires OK. I plugged in the LRP fan for mod use. Then the speed control failed. The speed control spent more than a month at LRP. They were waiting for a shipment of SXX version 2 TC spec. Based on my intended use they though it would suit my needs better and offered to trade up. I accepted. Turns out the version 2 has an upgraded battery eliminator circuit (BEC) and will work with one or two cell. GREAT! That is why I had the stock spec in the first place. Anyway here is a current pic. I put a LRP X-12 4.5 on it based on some one cell dyno runs I had performed recently. (The 3.0 pulled a huge 209 amps on a flywheel run, a 3.5 actually produced more power. A 4.5 is pretty close) I may be able to tinker with the speed control motor profiles a little with the 4.5. The car is a home modified CRC Carpet Knife, now with a dual A-arm front end, 3-link rear end, with hydraulic dampers from an RC18T on all four corners. The intended use is a bumpy long outdoor track. John |
the picture of miniaturization, John. Sweet!
|
4 Attachment(s)
Scimitar Wide Pan
Finally, I have a fully Scimitar Spec Wide pan for my own use.:D Attached are a few photos. I am still trying to get some duplicates cut, but am having much trouble. This chassis was machine cut, but not without errors. I had to hand sand it in four spots with the Dremmel. The countersinks were terrible. They were shallow and had tearouts from a dull bit. I recountersunk all the holes but there were still some minor flaws making the chassis unsaleable. The nerf wings had deep notches that I sanded out. Both suitable for my personal car though. I thought I would go through some pan car ills that I have tried to correct with the car. These were experienced starting in August 2006 in the Pantoura Thread. I tried a very wide variety of pan cars. These included The CRC Pantoura which is the subject of the above thread. (Center pivot side link) A Powell Racing Products, Wide Pantoura (graciously loaned to me) (center pivot side link) An Associated RC10L2O converted to road use (T bar with viscous disk roll control) graciously donated. Several converted oval cars (Rear Pivot short T-bar) The main differences in the cars were how the pod was joined to the chassis. I can rate a couple of important qualities fromt the test. Best throught the bumps, the Center pivot side link like on CRC cars and now on the Associated 1-10 pan. Best acceleration (the Rear pivot T-bar car). This car is much like the Center pivot car, in effect, but it has a pivot that is at the rear edge of the T-plate. The CRC pivot is slightly forward of this. This gives the Rear pivot T-Plate car better Antisquat and more forward grip. Best front turn in was the T-bar car with viscous disk roll control. This is probably the roll control with lightest action. Now here are some problems shared by all when using powerful motors on a large outdoor track. Sluggish acceleration on the second part of the straight. All the cars tended to bounce and touch only the tops of the bumps. The Center pivot side link car was best here but a full 4 mph slower by radar than my 3-link rear end car. Steering is imprecise.- I probably can give you the best example on the oval. If you do not turn in the sliding kingpin car just right midway in the straights you can forget running a tight line. You have to aim the car rather than steer it. This is corrected by my dual A-arm front end. You can steer and manouver all the way to the apex. Going Airborne on the Straight (Blowovers) This was the most vexing problem and was the hardest to solve. I tried many forms of the strut front end. I added shocks, I added a sway bar. The sliding kingpin was just unsuited to resolve the this problem. It had too much friction and not enough travel. I finally cured the problem with a dampened dual A-arm front end. It also helped a lot to add a diffuser just under the front lip of the body. The car is really sucked down now and does not bounce up in the air at all. All of these trials and experiments are recorded in the Pantoura thread followed by this thread. Some Good Scimitar Features
LRP SPX8 speed control (this speed control is most like the old LRP TC edition that also worked well in the car) LRP X12 3.5 motor Thunderpower 4200 mAH, 50C pack. This brand is the most heat tolerant that we have found. This prevents puffing up with use. KO PDS2413ICS, This servo is half height but full strength and speed. Test to come in a couple of weeks. That first pic can be blown up with a second double click and you can scroll around the car. John |
5 Attachment(s)
Here are a few pics of the different tests.
1 RC10L2O, the T-plate, Viscous disk rear pod 2, Home modified KSG Sway bar added to sliding kingpin. 3. Center pivot Side link on PRC wide pantoura 4. CRC widened Pantoura. My first wide pan. Note homade Aluminum front chassis extensions. These later became popular in graphite. 5. Superior Spectre Oval car showing Rear Pivot T-Plate. Note the row of pivots on the pod front edge. These are discussed a little in the post above. John |
john is there any chance you could write some thing up about front suspension in standard form, its hard to find decent information about active struts and how the different angles affect steering/handling on asphalt.
also angle of the steering arms when looking from over head and affects of steering arms inside or outside of servo saver thanks |
2 Attachment(s)
Here are some adjustments in order of largest effect first for the sliding kingpin strut front end.
Caster is an adjustment that can be really felt. Less caster gives you more initial turn in and less turn in mid corner. More caster gives the opposite. I like 4 degrees on asphalt to give me the amount of turn in I like. I don't like the front end super sensitive so a tiny flick into a corner causes me to lose the rear end. Reactive Caster-Reactive caster gives you a way to reduce caster mid corner. Say the pan car has good corner entry but mid corner you have too much steering and, are getting some spins. Then add the 2 degree reactive caster block this will reduce caster by 1 degree, but only when the car is rolled over hard in mid corner. This will cut your mid corner steering. I prefer 2 degrees reactive caster on asphalt. Camber is usualy adjusted for even tire wear on the front of a pan car. Unfortunately it is also tied up with roll center. More negative camber produces a lower front roll center and thus more grip. When you first start driving a pan car you can use 0 camber to lessen the tendency to wander on the straight. As you get more used to the car you will end up using -1.5 to -2.0 degrees of negative camber on asphalt. Ackerman-The need for the inside front tire to take a shorter radius turn in the corner gave us Ackerman. I have measured Ackerman on a pan car and found that angled steering links gives less ackerman. Whether they angle forward or back you will get less ackerman. If your ackerman is correct to start with and you lessen it you will get less steering. Some guys from our local oval asphalt club went to carpet oval nats. They came back with angled links to mute the steering on carpet. Quickly they returned to straight links for the asphalt. Moving the servo forward or back affects your front to back weight. More weight in the rear gives you more forward traction. I like the servo back on asphalt. On carpet you can have more weight up front. Having the ballstuds front or back on the servo saver is just a neccesity to keep the links perpendicular to the chassis given a particular choice of servo position. There is only room to mount a full size servo relatively forward so that it clears the inline 2 cell battery. John
Originally Posted by ozzy-crawl
(Post 9330772)
john is there any chance you could write some thing up about front suspension in standard form, its hard to find decent information about active struts and how the different angles affect steering/handling on asphalt.
also angle of the steering arms when looking from over head and affects of steering arms inside or outside of servo saver thanks Second Pic: Pantoura with an unsucsessful attempt to cure the blowover problem. Front shocks on the sliding kingpin suspension. |
thanks john, i think i am a little confused on caster.
i have a gen x 10le running on asphalt. i have 0,5,10 active strut blocks,then there is 3 white spacers to adjust caster from what i under stand the higher the angle = more entry steering less mid corner.( related to active strut blocks) were your saying less caster = more entry steering less mid corner. i take it I'm confusing active caster and static caster doing the same thing, were as there the opposite currently running 5 deg block,2 white spacers behind upper arm 1 in front. just trying to make the steering a little less sensitive. |
less caster (washers in front) more initial cornering steering (turn in).
more caster (washers in back), kingpin tilted back as it goes up, more midcorner steering traction. Adjust this first. I like 4 degrees. Active strut blocks/reactive caster blocks. This blocks tilt the upper arm. At rest there is no effect. On hard cornering as the upper arm moves up the reactive caster block reduces caster because of the angle. I believe the 5 degree block kills 1 degree of caster. So the purpose here is it allows you to tune turn in with caster and then you can fine tune midcorner with reactive caster. Your goal is to have good steering, but eliminate all initial and mid corner spins. The 10 degree block kills 2 degrees of caster mid corner. "currently running 5 deg block,2 white spacers behind upper arm 1 in front." That is 4 degrees of caster. Try running 3 white spacer behind and none in front of the arm (for 6 degrees of caster). Also stiffer front springs may be in order. John |
Thanks very much John if I am finding mid corner has to much steering would going to 10 deg reactive caster help then.
I may try you suggestion first Scott |
Originally Posted by ozzy-crawl
(Post 9335836)
Thanks very much John if I am finding mid corner has to much steering would going to 10 deg reactive caster help then.
I may try you suggestion first Scott |
Originally Posted by John Stranahan
(Post 9335775)
"currently running 5 deg block,2 white spacers behind upper arm 1 in front." That is 4 degrees of caster. Try running 3 white spacer behind and none in front of the arm (for 6 degrees of caster). Also stiffer front springs may be in order.
John how does moving the upper arm forward (3 spacers behind and none in front for 6 deg of caster) add caster, i thought adding caster would be laying the top of the king pin more towards the rear of the car. IE putting more spacers in front of the arm i must be missing some thing or looking at it ass about |
I used to get messed up wit hexactly the same thing. It's just weird geometry that's making it hard to undertstand. You (like me) are asssuming that the hinge-points are perpindicular, and the upper and lower arms are on a parralel axis. As far as I can eye-ball they aren't and that's what makes it work that way.
I think. ha ha |
It has confused me as well, but putting shims back moves the arm back, tilts the kingpin back, and adds caster. The center block is the stationary part.
john |
thanks guys, it was not i didn't believe john, just trying to work it out in my head and it seemed the opposite of what i thought lol.
did try the 10 deg active caster block today and it was terrible so went back to 5 deg. on another note my new ceramic nitride diff balls turned up today and what a difference very very nice. |
The good old days, when my Gen X 10 Pro was fresh out of the box. So much good pan car info. John really put in the time!
|
Hi John,
hope you are still around. rely like your thinking out of the box. hope you have more to show. |
diggin the battle axe
|
so is this thread dead?? or just intermittent.
any oval guys out there? https://cimg3.ibsrv.net/gimg/www.rct...0b4ab74b66.jpg ORT https://cimg4.ibsrv.net/gimg/www.rct...992df9a211.jpg BattleAxe 3.0 |
John Stranahan's Scimitar
Hello. I'm back after a long a time. Probably just to read. The suspension on the Scimitar is properly described as a 3 link rear end with panhard bar. Twin rear shocks. There are several advantages over a center shock with center pivot or T plate. Primarily it is more supple like an 1985 mustang area end compared to the previous suspension. Additionally the shocks don't rub the shafts on top and bottom like a center shock. Less shock wear. The rear pod stays much more flat over the full travel so it an be set at track minimum and the rear of the main chassis can be set higher to keep from rubbing on the bumps. This leads to better side and forward traction as tracks tend not to be flat. The front is a dual A-arm for better camber control and again lower friction for better cornering and traction through the bumps. I have one of the prototypes still in hand. A good speed control is the Tekin Rx. This should keep you from frying it on high traction days when you might be pulling huge amps coming out of the corners with a 3.5.
|
Here is a pic if I am successful.
https://cimg5.ibsrv.net/gimg/www.rct...fc8dfd4af9.jpg note beefy rear links hold adjustments much better. |
Not my front end
Not my front end.
|
All times are GMT -7. It is currently 05:34 AM. |
Powered By: vBulletin v3.9.3.8
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.