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Old 01-11-2007, 10:13 PM   #841
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6 cell stock is a BLAST and quite fast - somewhere between 19T and full mod.
I've driven 6 cell mod (9T) and we were able to run 4-5 minutes and extremely fast (just slower than 1/8, but faster than anything else) and it's very controllable. if you can run 6cell Stock, it's really not that much of a jump to full mod.

We ran this with nearly no mods - maybe an aluminum shock mount/antenna-rollover mount (changed the shock angle just a touch), we cut off most of the front bumper (both weight and because the danged things wanted to droop. . .) and a carbon fiber bottom plate on the pod. Some of us ran IRS axle pods, but many others didn't. Really - none of these mods made much difference - the car was still the car. . .

And John's running right at those speeds (even just a touch faster) but for longer periods of time.

His blowovers were because his front end was grounding then bouncing up and getting air under the car. This was a major reason for damping his front end.
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Old 01-12-2007, 06:13 AM   #842
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Thanks for the information and the front end dampining makes lots of sense.
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Old 01-12-2007, 10:04 AM   #843
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While we're on the subject of front suspensions...

I had a Corally CCT once - the european version of a Pantoura or RC10L3T. It had a beam-type front suspension made out of a single fiberglass plate, with a spring on each side. I made a simple damper for it. Just an alu plunger flex-mounted to the 'beam' going up and down into an alu body mouted into the chassis. The plunger had one or two O-rings, and I could put damping syrup or oil on it. It had about 5mm of travel, and total height was no more than 10mm. Worked very nicely!
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Old 01-12-2007, 06:07 PM   #844
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Elvo-Thanks for the description of your damping system.

3-link
I made a few small changes to the 3-link car. I had noticed that I like the steering better on the narrow chassis car when it was the 3-link car. The main difference was front springs and it had trailing front axles. I put new trailing axles on the wide chassis car with the 3-link and its steering improved. Now the big weakness for me was that two thirds through our sweeper the car with the inline axles would seem to get a driverless input for more steering and would tend to spin the car out. This was as if the in line axle was breaking over center and taking up the slack in the other direction. Anyway the trailing axles don't do this. They are a keeper. The trailing axles are also lower on the chassis. This let me put in another ride height washer which improves my shock angle. Anyway speed and stability were good on the straight again.

Double A-arm front suspension (pic)
Work proceeds on the double A-arm front suspension. I found a Traxas ST2 kingpin about .094 inch in diameter, with a built in ball on one end. I will use this for my upper shock mount and the upper A-arm inner pivot. I may have to resize the ball. I ordered an Aluminum set of pan car kingpins from IRS. These have a nut to take out kingpin slack. On this suspension the kingpin will not be required to slide up and down through bushings so the Aluminum parts may hold up fine while lightening things up at the wheel. If I was making parts from scratch I would lower the inner upper A-arm position. This would improve the roll center, sideways tire scrub on bump, and camber curve. On this car I plan to raise the outside of the upper link up with the longer IRS kingpins to achieve the same effect.
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Old 01-14-2007, 11:52 AM   #845
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Double A-arm front suspension Continued
Here is the latest version. I made an Aluminum upright to solve a steering link clearance problem. The Servo is mounted, tilted to the side, here to give a more up and down movement of the steering links. This gives me more clearance. Pic is at full bump.

Some desirable features
Great wheel travel
Very good shock travel. About double what I have now.
low stiction, no sliding parts except the shock shaft on the shock O ring. (It feels really smooth in my hands.)
Will Clear the low Nissan GTP and Peugeot 905B body
No shock tower neccesary so a very low hood (center) LMP body might fit well.
Roll center adjusts at the wheel by changing spacers.
Ride height can be adjusted at the chassis or using the shock.
Uses the factory holes on a narrow chassis to make it a wide chassis 212 mm wide at the front.
Crash parts are readily available. That custom upright is not, but it is very stout.

If I were starting from scratch I would lower the inner pivot of the upper arm maybe about 1/8 inch to lower things even more and to provide a good roll center.

I will use a combination ball/pivot pin for the upper shock mount eventually.
John

ps Warp speed is good! I can handle it, if the car could, and I am an old fart.
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-front-suspension-prototype-c-resized.jpg  

Last edited by John Stranahan; 01-18-2007 at 08:33 AM.
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Old 01-14-2007, 01:05 PM   #846
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Default Modiefied X10 track report

I finally had a chance to drive my car with all modifications a made lately.
I tried the lower rollcenter for the Tbar and side microshocks today.
After a few runs I removed the microshocks because they limited forward movement of the rear pod too much. The soldering tabs on the 3.5 motor hit the springs.
I did however get my car to handle very well, better than ever!
The low roll centre really seems to work!
The car felt very planted, although the track was very slippery.

The greatest testimony to my car's handling was when a 1/8th car got onto the track. It was one the best 1/8th pilots around here.
The funny thing was that he didn't get to catch up with me until my battery dumped! Now that is fun!

I am also really pleased with the 3.5 Novak's performance. Wicked fast, but very controlable.
The only thing is that I still have to program out the drag brake.
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Old 01-14-2007, 02:43 PM   #847
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Mathijs-Thanks for the report.


I have had that trouble with the solder tabs. They can be bent if that helps. Here is a view of the bend I use to clear my wide pod top plate. I also have narrowed a tab at the end on occasion. The lead wire is only 14 gauge. The tabs are much beefier than this. Also the endbell has many mounting screws see if the motor will fit better with the tabs back, the motor rotated one set of holes counter clockwise viewed from the pinion end. I would try those shocks again. Glad you had good luck with your 3.5.

Just a note to all: I was passing throught the LRP web site. I note that the LRP competition speed control is reccommended for brushless motors over 3.5 turns. That would mean a 4.5 or bigger.
John
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Old 01-15-2007, 02:20 PM   #848
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Prototype Double A-Arm Front Suspension Under Body

It looks like this suspension is going to work well for testing. I have lowered my uprights .050 inch for the lowest roll center possible. I have a little steering link rub when the right wheel is at full right lock. Depending on how much steering throw (adusted by the dual rate) is required this may not be a problem. I am using the rearmost hole on the steering arm. The Ackerman is different than before. As the right wheel turns left the left wheel turns on a different radius. The radii are farther apart from each other than before. I noticed that the new CRC pan car uses a new hole farther back than mine. This change to Ackerman may be OK. Still Waiting for a left side shock and longer kingpins.

The front of the body is at the height I normally use. The rear is a little lower than I normally use. The links are not quite at the proper angle yet. I will need to set this when I get the final roll center on the car.

Second pic shows the suspension with low roll center, low bumpsteer and good ride height for my track.
John
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-front-suspension-prototype-d-resized.jpg   Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-front-suspension-e-resized.jpg  

Last edited by John Stranahan; 01-16-2007 at 09:24 PM. Reason: Radii are farther apart. I compared it to my other car one on top of the other.
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Old 01-15-2007, 08:08 PM   #849
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Flipping the shocks over will reduce unsprung mass won't it? I thought you wanted the heavy oil filled end connected to the chassis..
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Old 01-15-2007, 08:14 PM   #850
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very interesting John
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Old 01-15-2007, 09:35 PM   #851
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Thanks for the posts.

Yes flipping the shock over would be better. I need clearance to turn the wheel, though. This way I get a few more degrees of steering throw. The shock is a smaller diameter around the cap than at the spring seat. I can look into different shocks if the front suspension does what I hope. It has long arms and low stiction. Traction on asphalt should improve. It has great shock travel so I may be able to go down the straight at full throttle during a race. It will be fast indeed if I can. The aluminum kingpin shafts will reduce unsprung weight when they come in. These shocks only weigh about .1 ounce without a spring. Their only fault so far is that they need Titanium Nitride coated shafts to keep from scoring from the grit on my track. The rear blue Aluminum ones (with shaft down) are wearing a little better.
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Old 01-16-2007, 08:32 PM   #852
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Almost ready to go. I just need some durability upgrade parts for the front end. Shock action on the front end is very nice. A short drop test (4 to 5 inch) can tell what is going on. The single Lipo is spaced on center with some stiff foam. TC Bumper foam would be ideal. Rear cross brace pushes down gently on pack. This way I only need one tape strap at the front. Almost ready to test. Exciting days. Front double A-arm suspension added 1 ounce. The car weighs 40 ounces ready to race. The pancar class minimum weight was 43 ounces with transponder. I am starting out with a red VCS Micro shock spring on these RC18 front shocks.

John
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-front-suspension-prototype-f-resized.jpg  

Last edited by John Stranahan; 01-16-2007 at 10:13 PM.
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Old 01-16-2007, 09:45 PM   #853
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holy cow - that's awesome.

almost makes me ready to park my ACR and pick back up my 10L2. . .



almost!
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Old 01-17-2007, 01:41 AM   #854
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that is awsome great job John cant wait to race you at mikes .John if you need some material call me i have some old chasis that i do not need if you need to make some parts if that will help you.
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Old 01-20-2007, 02:57 AM   #855
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John, are you into an experiment with the old Pantoura rear suspension?
I would really like to know the effect of using longer side links, say twice as long. It should reduce rear stear on corner entry, making the car more stable.
I now it's not the direction your heading, but could you try it?
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