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Old 10-18-2006, 11:17 PM   #376
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Quote:
Originally Posted by Pro ten Holland
Marty,
If you'de like, I can send you my CAD drawings of the new design I'm working on (the one I posted a screenshot of).
Pro ten Holland

Sure send them I will take a look at them!
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Old 10-19-2006, 02:28 AM   #377
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Thanks to John for starting this crazy thread , Mathjis for his years of Pan car experience (has helped me with pan car info in the past ) and Marty for his love and ability to design and make these cars a reality ( even though it might not be very profitable which i hope it is for you Marty ) , this has to be the most interesting and knowledable thread i have seen on a RC forum for years.

Cant wait for this car to become reality , i think it will blow the socks off the way alot of racers view racing and i for one will be purchasing one
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Old 10-19-2006, 04:58 AM   #378
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Progressive travel” is used to describe a suspension that takes very little pressure to activate it at the beginning of its stroke, yet requires progressively more force to compress it as the suspension and shock reaches full compression. The suspension is free to react to smaller bumps while still resisting bigger bumps and preventing the shock from bottoming out under a violent bump force. Giant’s simple single pivot cantilever design is quite progressive, being able to react to small frequency bumps but at the same time being very good at taking bigger hits

So someone tell me why it is that what I am doing is wrong or if it is regressive suspension Dynamics.

And I will make it out of Aluminum first!

I do not have a Mechanical Engineering: Dynamic Simulation Software on this computer but if someone would like to give me a copy that would be ok also!

This is also why I wanted to go with A of this drawing.

And the next is a Indy car they have been running a mono cantilever shock for years but I am not sure if they still do and the program I used for our F1 cars.
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Last edited by Marty Peterson; 08-03-2008 at 01:44 PM.
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Old 10-19-2006, 05:00 AM   #379
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Quote:
Originally Posted by SKJ
John
I have been watching the thread with a lot of interest, I love racing pan cars especially oval. As for the front ends they are already a few shocked front ends for the pan cars. They are used on the velodrome cars. The pictures are on Hobby talk. Here are the links. Some of the photo quality is not very good. I hope this gives you a couple of ideas.

Steve


http://www.hobbytalk.com/bbs1/showth...0&page=2&pp=15
http://www.hobbytalk.com/bbs1/showthread.php?t=118351

This will be the setup I use on my 235mm Belt drive car! along with our F206F1 rear suspension it is a copy of a 1/5 scale car.
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Old 10-19-2006, 05:55 AM   #380
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ahh, so it's spring rates that is the problem. i though the challenge was to keep the mass centered and lowered. i'm no engineer either, but i enjoy a good chalenge. for those casual readers that may just be reading along for fun, progresive suspension is fairly easy to understand. when a linear action is applied to a bellcrank(or any lever with a fulcrum). the closer the force is applied to the tangent of the radius of the bellcrank, the least progressive. as the action rotates around the bellcrank toward perpendicular to the original tangent, it becomes more progressive.. maybe i need another "paint" sketch.. lol i love geometry.. and they said i'd never use this stuff
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Old 10-19-2006, 07:16 AM   #381
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Well Brake out your etch-sketch and lets see what ya got Bud!

I got mine fired up and waiting!

ok J/K didn't anyone tell you I do everything the hard way!

I felt one of these would have worked as well and no weight and just a sprinf seat and nothing more but it would not be adjustable and you would use the same springs that are on the king pins.

Plus none of this is to scale there just Ideas.

I would need to do much more before cadding a part to cut!
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Selling HPI F10 Front Knuckles and Complete Rear Axles W/Diffs Ball and Gear.
W/12mm TC Hubs & W/14mm F1 Hubs Good for std bearing Pans cars. STD Bearings!
eBay item number: 200947192161,200947193175,200947187493

Last edited by Marty Peterson; 08-03-2008 at 01:42 PM.
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Old 10-19-2006, 09:24 AM   #382
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SKJ-Thanks for the links. I note that the first link is in agreement with me that suspension is the key to prevent blowovers. You can't leave a bump nose up. The suspension pictured later is much like Martys F1. It might be closer to the chassis, but it's hard to tell. I'll study it some more. Its also hard to tell where the servo is. That DNA suspension is one we discussed previously. It should work great, but is way too tall for GTP style bodies.

Glad you guys enjoy the thread. I enjoy making them. Just a hobby.

Progressive suspension is just a thought to prevent bottoming. A more linear suspension with good travel should work also. If there is that aluminum bellcrank in the system, it would be easy to change the characteristics with a small part that did not require an expensive mold.

I enlarged and resampled the pic. It looks like the shocks are in the space under the servo. The servo probably was raised up making the Peugeot Body not fit.


Marty-The stock 1/12 pan spring does not have enough travel. Pro Ten Holland tells me the 1/10 pan spring is longer.

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Old 10-19-2006, 09:51 AM   #383
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My ideal front suspension would be something like this:
http://www.hpiracing.com/graphics/instr/sm/sm-004.jpg
The only enhancement I'de like to see on it is a simple way to add damping. You only need a little to help keep the front tires on the ground.

Another way would be to make some simple mods to the Standard Associated front end to add damping.

I now use a little thick grease on the kingpins to create damping. Too bad that wears off after a few runs, and attract a lot of dirt.

Another thing to keep in mind is to keep the ease of ride height adjustment the Asso front end gives us. Just loosen two screws add or take away washers, tighten screws and readjust toe -> Ride height set in 30 seconds!
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Old 10-19-2006, 09:53 AM   #384
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Hi - just a clarification. . .I'm not arguing AGAINST what y'all are doing. . .I do think that some degree of innovation is always needed. . .

I'm only saying that simplicity needs to still be a large factor. . .

(and I broke these things all the time - I'm the only one I know of who SHATTERED an axle, and not at the pin. . .went through several chassis. . .I hold our local record for the number of T-bars in a DAY (6. . .but it was the first time I'd run 6Cmod). . . I AM the stress test! )

Why not use the inboard shock design of the F1 and just relocate the servo a bit?

And I don't agree that FRONT suspension is what's needed to prevent blowovers. . .think about that:

A suspension is only active when compressed (or somewhere in its compression cycle). As a car begins to lift, the front suspension is taken out of its compression cycle and is no longer a factor.

Now, if you're meaning that the front suspension is a factor in that it would help prevent bottoming out/catching and thus flipping the nose up to catch air. . .sure. I'm completely with you there!

But from your earlier discussion, it's not the catch and flip blowover, but rather having air get under the car "normally". . .

So, what is your intention with this suspension? (ooh, rhymes! sorta)
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Old 10-19-2006, 10:07 AM   #385
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When that tiny spring bottoms it sends huge upward force to the nose of the car. This raises the dam. That causes the blowover. That's what needs to be fixed. I don't know what you mean by catching.

I don't know how you will ever get enough travel from a dynamic strut front suspension as is. If you remove the spring and make it go past its normal travel it pretty much binds up, at least mine does. I have not examined the HPI.

Pro-ten Holland-Now I'm curious if when your front king pins feel like they have lost there shock action from the grease do you also need to relube the side dampeners. Maybe a side shock which are easy to install would cure this.

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Old 10-19-2006, 02:16 PM   #386
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I never have blowovers unless I clip a corner stone. And that's even at the same speeds 1/8th scale cars reach. I have only seen blowovers on the straight with cars that used way too much rear wing. Blowovers normally have nothing to do with the front end, more with using too much rear downforce.

I rarely have to put fresh grease on the damper tubes. No need for full shock absorbers anyway. You just need minimal damping side-to-side. Any damping you add takes away overall traction.

I agree with Boomer on keeping it as simple as possible. I would prefer an option that uses some kind of damper tube to create damping.

John, order some 0.020 1/10th scale front springs and 1/10th scale kingpins. They'll help, especially with a little grease on the kingpin.
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Old 10-19-2006, 02:20 PM   #387
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Quote:
Originally Posted by John Stranahan
I don't how you will ever get enough travel from a dynamic strut front suspension as is. If you remove the spring and make it go past its normal travel it pretty much binds up, at least mine does. I have not examined the HPI.
Now I see where your problem comes from. You need to give top pivot some more room. Ream away some material from the upper eyelet to make it move freely over its full range of motion.
Also polish the kingpins.
When I build a front end, I fiddle with it until it drops under its own weight all through its full range.

One thing that not much people know is that it's best to ream the hole in the steering block until it pivots freely on the king pin. Your front suspension will work noticeably better!
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Old 10-19-2006, 05:35 PM   #388
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Ahhh, I understand now. You want a suspension that works like a suspension! Whatever came over you?!!?!?!?

I can't say that I've ever had the issue you're describing, even at 70mph plus, but I can imagine the rebound.

I think that's one thing the Corally front suspension was built to work on, and it really is one of the smoothest designs I've seen - it somewhat combines a sway-bar and a suspension. . .works very well.

However, if that doesn't float your boat (LOL) I have seen a suspension that works very well with a single shock that is mounted transversely and connected to two turnbuckles which are actuated by the lower suspension arm. . .that seemed to be very effective as well.

in any case - and I see you're keeping this in mind - simple solution = better!

Anyway - it's fun watching!
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Old 10-19-2006, 06:48 PM   #389
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Well boomer, You have hit the nail right on the head.

Pro Ten Hollan- My suspension drops freely over its full range. I don't see any point if making it drop freely from a position that is higher than possible with the spring in coil bind. This would just increase play. If it drops freely over the 2.5 mm of possible movement then that's all it's ever going to see. I do see where there may be some improvements if the steering knuckle can pivot more freely. I'll give that a try. I'll study your post some more. If you don't have a blowover problem its probably because the track is smoother. Some Nitro cars have blown over on this track as well. I also have a suspicion that an Associated front end without any friction will bottom more severely and increase the problem. Should not have to "Waller" the supension out to make it move properly. Thats a Texas term I think.

Track Report- Track was wet. We vacuumed about 60 gallons of water off of it and it looked dry after some down time, but it was not dry. I had droplets under the body. The body must be doing its job now as its sucking water out of a dry looking track, probably out of the minute cracks as there were no puddles or wet spots. I had a lot more steering from the recent body adjustement. Went back to the protoform wing. Went up to purple front tires. Tomorrow I will have a dry track for a better test the performance on the straight. I had a second racer, Robert, confirm that the car handled better with the McAllister body in the infield. "less likely to spin out".

RC10L
I had my hands on Roberts new to him RC10L which shows very little use. We had fun setting it part way up. I notice on this car the servo is flat to the chassis and the tie rods feed off the top of the servo. So what is the advantage of a Servo angle upward other than to create more chasis space or is chassis space the main reason.

Orion Avionics 3200 mA-h LiPo

At last an Orion LiPo is available in a pack that will go into my two cars. The guts of this pack are supposed to be the same as the graphite look pack with the hard shell. The photo shows that there is clearance in the front and on top in the Pantoura. On a normal day this capacity will run my car about 17 minutes. On high traction days about 12 minutes. The Pic also shows that the very inner silver shrink is exposed. The battery is a suitable size that I can add protection too it rather than have to take it away. I will add a little LEXAN sheet maybe .030 top and bottom to take up the space and to take any end thrust from a crash and I will add my thick blue shrink. I have a full length battery support on the near side and a foam support on the opposite side on the sides. This should do well. One thing I have noticed about these packs is the guts are soft. With a lot of use and time they tend to extrude into the battery slots on the bottom. (this is actually an advertized advantage of the packs, they can be shaped to fit irregular spaces) The lexan would prevent this. A non milled chassis would also work.

John
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Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-orion-avionics-pack-001-resized.jpg  

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Old 10-19-2006, 10:30 PM   #390
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10L
The 10L was originally put out with the Old School "block of Nylon" front suspension. On that, the servo was laid flat. The servo is angled on the dynamic strut front end to correct bump steer and ackerman.

Blowover:
On the Peugeot, did you cut out the two rectangles on the middle of the rear wing? This normally helps against blowovers.
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