R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 01-30-2006, 12:56 AM   #1
Tech Adept
 
Join Date: Sep 2005
Posts: 137
Default Are cars with variable chassis stiffness the future?

First the FT TC4 arrived with a chassis with substantially variable stiffness. One magazine review gave the nod to the TC4 over the HPI Pro4 because the TC4 could be used on asphalt and carpet out of the box simply by adding or removing chassis stiffening posts. On the other hand, to tune the Pro4 for carpet, you need all new top and bottom chassis plates (costing big $$$ and lots of time to move parts over).

Now the Xray T2 is here with a very similar concept.

Will all cars adopt this approach?

Of course, AE has just released new thicker chassis plates for the FT for carpet, so perhaps one size does not fit all.

Any thoughts?

Ira
iblumberg is offline   Reply With Quote
Old 01-30-2006, 01:21 AM   #2
Tech Regular
 
Join Date: Dec 2005
Location: CA
Posts: 458
Default

and why is it at club level lots of the fast guys are running a ta05 with tub chassis?? end of the day its not down to the car, its 99% the driver.
XingXing is offline   Reply With Quote
Old 01-30-2006, 02:05 AM   #3
Tech Addict
 
Simon K's Avatar
 
Join Date: Aug 2001
Location: Wellington, New Zealand
Posts: 573
Default

It's been done before, The Yokomo YR4 M2 had a row of posts you could add down the center of the car to stiffen the chassis.

It's just another tuning option, it comes and goes out of fashion the same way shock towers with multitudes of holes do
Simon K is offline   Reply With Quote
Old 01-30-2006, 06:31 AM   #4
Tech Elite
 
Mason's Avatar
 
Join Date: Oct 2004
Location: Ocala, Florida
Posts: 4,909
Default

future? its the past. this is nothing new. Manufacturers have only made it easier for joe racer.
__________________
Mason McCombs
NewRed Hobbies & Indoor Facility
Off-Road, Dirt Oval, Crawlers & Pullers
Mason is offline   Reply With Quote
Old 01-30-2006, 08:09 PM   #5
Super Moderator
 
Grizzbob's Avatar
 
Join Date: Feb 2002
Location: Sand Springs, OK
Posts: 3,063
Trader Rating: 2 (100%+)
Default

Right, & not only is it past, it's present again, which has a lot to do with why I bought my FT TC4(& I also used to have one of those old Yokomo YR-4 M2 USA & Pros with the variable stiffness, always LOVED having that option). Also, to clarify on the new FT TC4 parts, they aren't stiffer, they're actually more flexible, meant for use on lower grip surfaces to give the car even more tuning options(the original chassis plates are PLENTY stiff as is).....
__________________
Bob Seay
Tamiya TRF417, TA05v.2, TRF211XM, M-05ver.2R, XRAY X12, Associated B5m Factory Lite

Go Pokes!!!
Grizzbob is offline   Reply With Quote
Old 01-30-2006, 08:21 PM   #6
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

Tuning with chassis flex is a little puzzling to me. You never hear of a full size car designer wishing his chassis was more flexible, in fact every effort is made to make it stiff while still lightweight. When you make the chassis flexible it detunes the car. That means that instead of moving 1 hole out to tune your oversteer understeer balance you may have to move two holes out because of the lack of chassis rigidity to transfer weight properly. On a high grip indoor asphalt track the HPI molded chassis that is super flexible is very hard to tune in in my experience. You end up using stiffer spring rates than you would otherwise on one end of the car. I still need to be convinced that the car will actually run better with flex than by adjusting it in with the proper spring rate front and back.


The FTTC4 spine is not a good way to adjust chassis stiffness as you are left with mating parts that slide against each other. This might cause chassis tweak. I notice that instead some racers remove the 4 outboard posts instead. This will not cause tweak problems.

Now using flex in the suspension arms is in vouge in Formula I. Here flexures are used instead of a lower arms and coil springs on the front of the car. The lower arm is solid graphite fibre piece that flexes. This reduces suspension friction immensely. Lowering suspension friction also seems to help our cars a lot. I wonder if flexures would be allowed by the rules.
John Stranahan is offline   Reply With Quote
Old 01-30-2006, 09:22 PM   #7
Tech Adept
 
Join Date: Sep 2005
Posts: 137
Default

Quote:
Originally Posted by John Stranahan
Now using flex in the suspension arms is in vouge in Formula I. Here flexures are used instead of a lower arms and coil springs on the front of the car. The lower arm is solid graphite fibre piece that flexes. This reduces suspension friction immensely. Lowering suspension friction also seems to help our cars a lot. I wonder if flexures would be allowed by the rules.
That is very interesting. HPI makes more flexible suspension arms for the Pro4. These are said to help on low traction surfaces. Because of the parts overlap, they also fit the new Hot Bodies Cyclone.

Ira
iblumberg is offline   Reply With Quote
Old 01-30-2006, 09:24 PM   #8
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by iblumberg
HPI makes more flexible suspension arms for the Pro4.
So does Schumacher, Xray, Hot Bodies and Corally. Tamiya just uses HB arms
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
AdrianM is offline   Reply With Quote
Old 01-30-2006, 09:40 PM   #9
Tech Master
 
BlackKat's Avatar
 
Join Date: Oct 2004
Location: Northside San Jose, CA
Posts: 1,335
Default

I've seen a few people run their Tamiya cars with the center ribs of the arms dremeled out. I'm going to try this on the Associated car myself

Ira: I'm Daniel...the kid who runs the TC4 down at Gilroy. I'm working hard to keep my title as "Fastest TC4 at the track on rubber tires"
BlackKat is offline   Reply With Quote
Old 01-30-2006, 09:41 PM   #10
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by John Stranahan
Tuning with chassis flex is a little puzzling to me. You never hear of a full size car designer wishing his chassis was more flexible.
As stated below we have been through this over and over again over the last 20 years of R/C car development. The key point that Engineers and inexperience r/c racers seem top gloss over when drawing comparisons with real cars is that a full scale cars does not weight 21 lbs, travel at 400mph and generate 6G's of cornering force.

Stiff cars are great on carpet where the stiff chassis helps to shed excess traction. On asphalt stiff cars slide.

The current crop of top asphalt cars come with 2mm chassis. They flex a little (a bit of force is needed to get them to flex) and this help them generate more traction. More traction = more steering, corner speed and forward bite.
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
AdrianM is offline   Reply With Quote
Old 01-30-2006, 09:42 PM   #11
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

The advantage of the flexure is that you eliminate an A-arm pivot as well as that you unload the shock pivot as there is no spring required. This is where the flexure helps. The flexible arms may help in some way but not like a flexure. I would still prefer my chassis stiff (with soft springs if neccesary) and the A-arms stiff to preserve suspension geometry. I am not a proffesional RC driver however.
John Stranahan is offline   Reply With Quote
Old 01-30-2006, 09:50 PM   #12
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

Adrian- Yeah, but you still have not said anything to convince me. That's a handwaving type of argument. The RC manuals from various manufactures don't even agree on simple things like what the spring rate will do when you increase it on the front end. I find completely backwards ideas of weight transfer, spring rates, etc on and on. So don't call me inexperienced. I have plenty of that.

Last edited by John Stranahan; 01-30-2006 at 10:12 PM.
John Stranahan is offline   Reply With Quote
Old 01-30-2006, 09:52 PM   #13
Tech Master
 
bender's Avatar
 
Join Date: May 2004
Location: Brisbane
Posts: 1,504
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by John Stranahan
I would still prefer my chassis stiff (with soft springs if neccesary) and the A-arms stiff to preserve suspension geometry.
I couldn't agree more

My newest tc (tamiya msx) has quite a lot of chassis flex, yet only last weekend I found that by running very stiff springs on a low grip track (with rubbers), I was able to generate MORE grip and corner speed

The softer my car is, the slower it is around the track, even on a low grip track - so I'd prefer a very rigid chassis to allow me to tune the car through the suspension only, and not have to worry about how much the chassis is flexing around the corners.
__________________
Jason W
FIR#2 - "You can't buy this much talent"
Durango Dex410 - Schumacher Cougar SV - Top Photon
bender is offline   Reply With Quote
Old 01-30-2006, 09:52 PM   #14
Tech Elite
 
ChadCapece's Avatar
 
Join Date: Sep 2004
Location: CofC
Posts: 3,313
Default

TC4 came up with nothing new. Infact, the Pro4 CAN be stiffened or softened with the center chassis brace. Somehow, that mag failed to mention that part during their review.

Tunable Chassis'

Pro4
TC4
Evo4
415
FK05
T2
T1's
SD SSG


Those are just a few examples.
ChadCapece is offline   Reply With Quote
Old 01-30-2006, 10:25 PM   #15
Tech Champion
 
AdrianM's Avatar
 
Join Date: Aug 2001
Location: Tampa, FL
Posts: 5,914
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by John Stranahan
Adrian- Yeah, but you still have not said anything to convince me. That's a handwaving type of argument. The RC manuals from various manufactures don't even agree on simple things like what the spring rate will do when you increase it on the front end. I find completeldy backwards ideas of weight transfer, spring rates, etc on and on. So don't call me inexperienced. I have plenty of that.
What do you want for proof John?

Here are some oldies...

Its 1995 and Yokomo is selling the Yr-4M2. It pretty much has spring on the top deck and it was a very fast car. Lots of companies made top decks to eliminate the spring and stiffen the car. The stiff top deck made the car useless.

Its 1997 and Masami discovers that their plastic Mr-4 is faster than their carbon Yr-4M2Pro. Masami and Barry win a ton of racers with that cheap plastic car. Yokomo comes out with the Mr-4 Pro Graphite. Its super cool and super slow....until...Masami starts cutting up the top deck to make the car flex. Barry won every race, every where with that car....except the Worlds...Hara won that! Yokomo Releases the World's Edition Mr-4 with the top deck milled out of the box.

1999 The TC3 comes out. On Asphalt all the team drivers mill out ribs to make the cars flex more...to make the car faster.

The suspension systems in our cars are not as sophisticated as they are on real cars. You cannot make a stiff car as fast on asphalt as a flexy car no matter how soft you go on springs and oil.

If you look at the setups from Schumacher, Tamiya, Xray, Hot Bodies, etc. you will find that on asphalt they are running flexy chassis and light springs (17-14lb) and oil (20-35wt) so its not like they are running stiff suspension and flexy chassis.
__________________
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
AdrianM is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for a variable power supply minicooper Radio and Electronics 2 04-12-2008 11:25 AM
Looking for variable power supply minicooper Electric On-Road 3 04-11-2008 11:03 AM
I need some really stiff 1/10 onroad springs,how do i know the stiffness? GunMetal Nitro On-Road 2 06-25-2007 07:05 AM
Is there a variable rate discharger available? Rapid Roy Electric On-Road 7 08-24-2005 02:50 PM
variable speed dremel THE_REAL_FROBOY Other Items: For Sale/Trade or Wanted to Buy 3 06-07-2005 09:42 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 03:49 AM.


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