Onroad speed runs with a Stadium truck....

[10k]

Rather than using an onroad sedan, I'd rather use a stadium truck for
some winter "wow" speed runs. I've been wanting a stadium truck anyway
lately, so this will get me motivated.

I'm going to go with a T4, and some brushless setup. Most likely will
slam it down as low as I can for handling, stiffen everything up, get
some good meat for the wheels, and hold on.

Are speeds capable of reaching 70 MPH or more with the ST's? I never
see posts about people pushing the limits with these cars, but I think
it'd handle a bit better since it's wider.

[Jonathan Hodgson]

On 10 Dec 2004 05:27:37 -0800, 10k wrote:

> Rather than using an onroad sedan, I'd rather use a stadium truck for
> some winter "wow" speed runs. I've been wanting a stadium truck anyway
> lately, so this will get me motivated.
>
> I'm going to go with a T4, and some brushless setup. Most likely will
> slam it down as low as I can for handling, stiffen everything up, get
> some good meat for the wheels, and hold on.
>
> Are speeds capable of reaching 70 MPH or more with the ST's? I never
> see posts about people pushing the limits with these cars, but I think
> it'd handle a bit better since it's wider.

It's going to have more drag than a buggy or tourer, due to:
- the big, wide wheels
- the long, exposed suspension arms
- the open underside to the body (I suspect)
- possibly the general shape of the body.

In particular, I'd consider trying to find (or make - cut'n'shut!) some
narrow tyres and wheels, since I think this will make a big difference
to the aero drag.

If you're serious about it, you could also think about cutting away the
rear of the shell, removing that rear air-brake trucks all seem to run,
and maybe fairing-in (or rounding the leading edges of) the wishbones.

As for stability - the extra width *might* help, but then wide short
vehicles are generally said to be more twitchy than narrow, long ones.

HTH - let us know how you get on!
Jonny

[Justin Mahn]

Jonathan Hodgson wrote:
> On 10 Dec 2004 05:27:37 -0800, 10k wrote:
>
>
>>Rather than using an onroad sedan, I'd rather use a stadium truck for
>>some winter "wow" speed runs. I've been wanting a stadium truck anyway
>>lately, so this will get me motivated.
>>
>>I'm going to go with a T4, and some brushless setup. Most likely will
>>slam it down as low as I can for handling, stiffen everything up, get
>>some good meat for the wheels, and hold on.
>>
>>Are speeds capable of reaching 70 MPH or more with the ST's? I never
>>see posts about people pushing the limits with these cars, but I think
>>it'd handle a bit better since it's wider.
>
>
> It's going to have more drag than a buggy or tourer, due to:
> - the big, wide wheels
> - the long, exposed suspension arms
> - the open underside to the body (I suspect)
> - possibly the general shape of the body.
>
> In particular, I'd consider trying to find (or make - cut'n'shut!) some
> narrow tyres and wheels, since I think this will make a big difference
> to the aero drag.
>
> If you're serious about it, you could also think about cutting away the
> rear of the shell, removing that rear air-brake trucks all seem to run,
> and maybe fairing-in (or rounding the leading edges of) the wishbones.
>
> As for stability - the extra width *might* help, but then wide short
> vehicles are generally said to be more twitchy than narrow, long ones.
>
> HTH - let us know how you get on!
> Jonny
New era has some axle converters to put 1/8 buggy wheels on an RC10GT.
That should help with the gearing up you're going to need to do, as well
as give you more narrow profile on the wheels.

[walker]

"Justin Mahn" <gabril@cox.net> wrote in message
news:imEud.126917$%x.72835@okepread04...
> Jonathan Hodgson wrote:
> > On 10 Dec 2004 05:27:37 -0800, 10k wrote:
> >
> > Jonny
> New era has some axle converters to put 1/8 buggy wheels on an RC10GT.
> That should help with the gearing up you're going to need to do, as well
> as give you more narrow profile on the wheels.

I think this would be a help. The trouble with long arms at speed is
that any wear in the attachment point becomes more pronounced. ( A .010
movement at the end of a 1 in. arm becomes .030 at the end of a 3 in. arm.
which is a lot of wooble at 60 or 70 mph. A close-coupled car is easier to
keep tighter as well as minimizing flex in connecting members etc. Sounds
like you're on the right track though.


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[kenji]

In article <gaednUweltfiNSbcRVn-sA@comcast.com>,
"walker" <ctwalker99nospam@comcast.net> wrote:

> "Justin Mahn" <gabril@cox.net> wrote in message
> news:imEud.126917$%x.72835@okepread04...
> > Jonathan Hodgson wrote:
> > > On 10 Dec 2004 05:27:37 -0800, 10k wrote:
> > >
> > > Jonny
> > New era has some axle converters to put 1/8 buggy wheels on an RC10GT.
> > That should help with the gearing up you're going to need to do, as well
> > as give you more narrow profile on the wheels.
>
> I think this would be a help. The trouble with long arms at speed is
> that any wear in the attachment point becomes more pronounced. ( A .010
> movement at the end of a 1 in. arm becomes .030 at the end of a 3 in. arm.
> which is a lot of wooble at 60 or 70 mph. A close-coupled car is easier to
> keep tighter as well as minimizing flex in connecting members etc. Sounds
> like you're on the right track though.

At some point he'll mod it out, and it will end up looking like a TC3.

[Justin Mahn]

kenji wrote:
> In article <gaednUweltfiNSbcRVn-sA@comcast.com>,
> "walker" <ctwalker99nospam@comcast.net> wrote:
>
>
>>"Justin Mahn" <gabril@cox.net> wrote in message
>>news:imEud.126917$%x.72835@okepread04...
>>
>>>Jonathan Hodgson wrote:
>>>
>>>>On 10 Dec 2004 05:27:37 -0800, 10k wrote:
>>>>
>>>>Jonny
>>>
>>>New era has some axle converters to put 1/8 buggy wheels on an RC10GT.
>>>That should help with the gearing up you're going to need to do, as well
>>>as give you more narrow profile on the wheels.
>>
>> I think this would be a help. The trouble with long arms at speed is
>>that any wear in the attachment point becomes more pronounced. ( A .010
>>movement at the end of a 1 in. arm becomes .030 at the end of a 3 in. arm.
>>which is a lot of wooble at 60 or 70 mph. A close-coupled car is easier to
>>keep tighter as well as minimizing flex in connecting members etc. Sounds
>>like you're on the right track though.
>
>
> At some point he'll mod it out, and it will end up looking like a TC3.


Agreed about the part where it no longer looks like a stadium truck, but
I doubt it'll ever look like a TC3, at least chassis-wise. :-D

[mike]

A T4 at 70 mph???? I would like to see that, even if only briefly (as would
be likely:-).

Seriously, I think this will be kind hard to attain unless you go totally
crazy with an "E" sized brushless (ker-CHING:-) with appropriate cell-age
(ker-CHING:-), at which point you will be doing things like torqueing CVD
pins (ker-CHING! :-) and heaven knows what else (ker- well you get the
message by now:-). I can tell you that the MIP CVD's which ship with the
RC10B/T4 can struggle even with a good quality stock motor on a
total-traction (ie sealed) surface, and I speak from personal experience. At
the very least you will need something like the GPM Titanium CVD's if you
can find 'em. At which point the load shifts to somewhere inside the tranny
...... I suspect the ball diff would be the next point of failure, but I
would love to find out - of course on your truck, not mine!

Anyway, if speed is your only criteria and you want a ST, why not try a
Mini-T? There are guys with Mini-T's using the Mamba brushless with lipo
cells who are posting numbers in the vicinity you are chasing. And of course
when it all goes pear shaped (and it will with a ST at those speeds) then
the replacement costs might not be so ruinous!

MIKE



"10k" <sirhc5379@hotmail.com> wrote in message
news:1102685257.782909.159160@c13g2000cwb.googlegr oups.com...
> Rather than using an onroad sedan, I'd rather use a stadium truck for
> some winter "wow" speed runs. I've been wanting a stadium truck anyway
> lately, so this will get me motivated.
>
> I'm going to go with a T4, and some brushless setup. Most likely will
> slam it down as low as I can for handling, stiffen everything up, get
> some good meat for the wheels, and hold on.
>
> Are speeds capable of reaching 70 MPH or more with the ST's? I never
> see posts about people pushing the limits with these cars, but I think
> it'd handle a bit better since it's wider.
>

[10k]

I actually have a RC18T truck now that is going to be used for speed
runs as well (only thing I don't own that isn't made for speed is my
MGT). The stadium truck just looked more interesting than the micros,
but I must admit, trying to control a mini over 40 MPH is a handfull,
and I'm relatively experienced.

I don't worry about snapping driveshafts and things like that, I start
off slow and build up to the speed, so it's not just a sudden 10+ volts
going onto an insanely torque-filled motor and thus, twisting the
shafts. Usually it's all good going nice and easy in the beginning of
the run. Radio range helps a ton (FM).

Ceramic nitride ball diffs help out as well, barely any heat
buildup........

[Dean]

On 17 Dec 2004 10:11:15 -0800, "10k" <sirhc5379@hotmail.com> wrote:

>I actually have a RC18T truck now that is going to be used for speed
>runs as well (only thing I don't own that isn't made for speed is my
>MGT). The stadium truck just looked more interesting than the micros,
>but I must admit, trying to control a mini over 40 MPH is a handfull,
>and I'm relatively experienced.
>
>I don't worry about snapping driveshafts and things like that, I start
>off slow and build up to the speed, so it's not just a sudden 10+ volts
>going onto an insanely torque-filled motor and thus, twisting the
>shafts. Usually it's all good going nice and easy in the beginning of
>the run. Radio range helps a ton (FM).
>
>Ceramic nitride ball diffs help out as well, barely any heat
>buildup........

I honestly don't think you will have a problem with the powertrain. I think
your problem will lie in handling and catching the wind. I would reccomend at
least going to a buggy rather than a stadium truck. The buggy's tend to develop
a high speed push, which is just what you want. Not to mention being MUCH more
streamlined.
---
Losi XXX KE <the racer>
Losi XX "CR" <the basher>
Associated RC10GT <the other basher>
http://ripperd.com
email: dean (at) the above domain

[kenji]

In article <82a7s01has83ftpbvd7uo8kvj0eumn9gsd@4ax.com>,
Dean <look@sig> wrote:

> On 17 Dec 2004 10:11:15 -0800, "10k" <sirhc5379@hotmail.com> wrote:
>
> >I actually have a RC18T truck now that is going to be used for speed
> >runs as well (only thing I don't own that isn't made for speed is my
> >MGT). The stadium truck just looked more interesting than the micros,
> >but I must admit, trying to control a mini over 40 MPH is a handfull,
> >and I'm relatively experienced.
> >
> >I don't worry about snapping driveshafts and things like that, I start
> >off slow and build up to the speed, so it's not just a sudden 10+ volts
> >going onto an insanely torque-filled motor and thus, twisting the
> >shafts. Usually it's all good going nice and easy in the beginning of
> >the run. Radio range helps a ton (FM).
> >
> >Ceramic nitride ball diffs help out as well, barely any heat
> >buildup........
>
> I honestly don't think you will have a problem with the powertrain. I think
> your problem will lie in handling and catching the wind. I would reccomend
> at
> least going to a buggy rather than a stadium truck. The buggy's tend to
> develop
> a high speed push, which is just what you want. Not to mention being MUCH
> more
> streamlined.

Here's my suggestion:

Take the stock truck, with a motor installed, but take the brushes out,
radio on, truck on.....have a fullsize car go 80MPH, drop the T4 onto
the pavement, and try and control the T4. See what happens.

Of course I'd trim the heck out of the steering on the radio.

this would give you a good aerodynamics test.