Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Post all of your steering modifications to get more angle and to fix ackerman on your chassis.
mx_masta
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Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 2:44 am

OK so most efforts at improving the steering on the HSP / REDCAT / HPI Maverick Strada have really only succeeded in increasing the Ackermann angle.
That is, yes the inner wheel gets more steering angle but the outer wheel gets a lot less.

This has been due to lengthening and angling the steering arms to get more steering output angle.
Anyone who knows will tell you that introducing angles to steering geometry causes Ackermann.

A much better way to improve the steering output angle is to remove the Ackermann link and replace it with an extended steering plate.
No extra angles are added to the arms this way, it's more like a translation of the end of the arms closer to the hubs.
The task of improving the steering output angle then comes down to simply the steering input angle (servo position) and the hole position in the hubs.
The task of achieving zero or close to zero Ackermann angle comes down to playing with the geometry of the extended steering plate to induce a little reverse Ackermann and therefore come out roughly neutral.

Here are some images of my design based on the existing geometry of the HSP (with drilled hubs and shortened steering links)

Image

The neutral position includes 3° toe out and the steering links are shown attached to the primary (inner forward ) hole position.
For those running more or less toe the outer forward holes will induce a touch more reverse Ackermann and the inner rear holes a touch less.
As you can see at 20° input angle the outer hub has caught up to the inner hub and at 38° input angle there is a slight amount of reverse Ackermann.
You will also note that the steering output angle is now 45-46° which is what I was aiming for.
That is about the limit on this chassis with a 195mm body, since at full lock the outer wheel is very close to the lower shock mount.

Next onto making the plate.


KEYWORDS; HSP FLYING FISH REDCAT MAVERICK STEERING UPGRADE STEERING MOD C-HUB DELETE ZERO ACKERMANN ACKERMAN
Last edited by mx_masta on Sun Feb 10, 2013 9:52 pm, edited 5 times in total.

mx_masta
Rally Style Drifting
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 3:56 am

This will be a lot easier with pictures and comments on each so here we go;


First off, print the template below with no scaling, you can download this from image shack via "right click, save as".

Image


Then stick this down onto some 3mm or 1/8" aluminium flat bar and centre punch the internal radii and hole axes.
Make sure the long edge is along the edge of the flat bar.

Image


Then drill through holes;
-6 link holes 3/32"
-2 pivot holes 1/8"
-6 internal radii pilot holes 1/8"
Next is to tap the 6 link holes to M3, use a good tap with a nice taper and only just break through the other side. This will mean that there are a few incomplete threads for the screw to bite into.
Be care full with this because if you stuff this up you might as well start over.
Use a light lubricant and don't forget to back out the tap 1 turn out for every 2 turns in, I also like to back the tap right out when I'm half done to clean the tap.

Image
Last edited by mx_masta on Sun Feb 10, 2013 6:41 am, edited 1 time in total.

mx_masta
Rally Style Drifting
Rally Style Drifting
Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 4:36 am

Next you can open out the internal radii pilot holes to 7mm or 9/32" and start trimming off the excess ally.
I used a hack saw (not the one shown in photo) to quickly get to this point, after here it's onto the Dremmel.

Image


The roughed out shape after hack sawing and Dremmel.

Image


Next I switched to mounting the Dremmel in the vice while taking off the clean-up allowance, don't forget the safety glasses!

Image


Next up, C-hub delete to allow more angle from the hubs.

And now the finished piece after a bit of sanding and de burring of the holes.

Intentional full size image link.
http://imageshack.us/a/img515/5191/0000255t.jpg


Next up the C-hub delete to allow the increase in output angle.

mx_masta
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 6:07 am

Now most other steering mods to the HSP / REDCAT / HPI Maverick Strada involve grinding the hubs and C-hub carriers to allow the hub more range of movement.
Now that just doesn't cut it for me, stuff breaks enough in normal circumstances without adding more weak points.

So I hatched a plan to delete the C-hub carriers.
The plan needed 2 things; cheap arms to control the camber and caster and suitable CVD's that wouldn't bind at 45°.
Both were found in the "cheap as chips" upgrade list for the HSP TC/DC and buggy.
-HSP; 102017 link for 1:10 car,
-HSP 106017 link for 1:10 buggy &
-HSP 122015 universal driveshaft fro 1:10 car.
All up less than $20 from ebay.

I wasn't too impressed at how sloppy the links were on delivery but clamping them in my vice between a couple of hex sockets fixed that.
The CVD's meanwhile I was happy with, they're easily capable of 45°.

Image


So that just leaves assembling it all to my HSP chassis.

mx_masta
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Drift Chassis: HSP Flying Fish
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Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 6:19 am

Now the plan was to mount the inner end of the links to the steering pivots.
One of these is a screw which poses no issues, however the other is a stud and lock nut.
The stud was not long enough to mount the link and still get the lock nut on.

So I had to extend the A pivot stud, I did this by way of a spacer under it.
These were found at my local electronics supply/hobby shop Jaycar; http://www.jaycar.com.au/productView.asp?ID=HP0860
Now the spacer was almost a match for the diameter of the pivot stud.

Image


I drilled out the end of the servo saver sleeve and reassembled the stud in the order shown.

Image


The steering arms also needed to be shaved of all of their assorted lumps to provide a flat surface for the steering plate.

Image


Extended stud reassembled to the chassis.

Image


Next up, the mods to the hubs.

mx_masta
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 8:47 am

OK so almost done, just the hubs left to modify.

Shown in yellow here is the cut made through the C-hub carriers, note the retained piece of the C-hub with the cut plane shown is in red.

Image


Shown here is the new holes drilled in the hub, there is actually a circular casting mark right were I drilled so it's easy to place.

Image


So now onto the final assembly details.

There's 6mm spacers on the steering arm link mounting points to get the bump steer geometry right.
As the screws must bite into the plate I recommend using cut screws rather than ones that are just the right size.
There's also 8mm spacers between the camber and caster links to clear the tyres.
If I was using a 200mm body and higher offset wheels these probably wouldn't be needed.
You can also see the washers that are tensioning my servo saver since in modifying the sleeve I removed the threaded portion.

Image

Image

Image

Image

Yes I know that the caster link geometry is pretty bad due to the 8mm spacers but a bit of bump caster won't harm handling too much.

Image


Next up the resulting steering angles.

mx_masta
Rally Style Drifting
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Sun Feb 10, 2013 9:27 am

Neutral

Image


Full left

Image


Full right

Image


And that's how it's been for a few weeks now, in which time I've done a couple of other small mods such as adding droop adjustment screws and rear toe adjustment eccentric screws.
So far so good. it's much easier to drift smoothly, easier to initiate and hold a drift.
Before I'd really have to feint flick it or stab the brake to get a tight drift going all I need do now is back off the throttle a bit.

Next mods on the to-do list are a little bit of rear O/D, most drifting tracks here are bitumen or asphalt so I don't wanna go too nuts.
But first I really need more practice and to fine tune the chassis settings.

Tomorrow I'll post a quick video if I get a chance.

rudeboy03
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Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby rudeboy03 » Mon Feb 11, 2013 7:30 am

Nice job on the custom steering linkage setup. A lot of people are afraid to bother trying to mod these chassis due to the lack of adjustability. Unfortunately the quality and design of these chassis are lacking compared to some of more expensive, higher end options. But this a great example of how even the most unlikely of chassis can be quite capable with a little bit of ingenuity, patience and elbow grease. Keep up the good work. And I hope to see some video footage of your mighty mini car mods in the near future. |O|
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mx_masta
Rally Style Drifting
Rally Style Drifting
Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Mon Feb 11, 2013 4:22 pm

Thanks, yeah it's hard sometimes owning a chassis with virtually no after-market support. But that's nothing that a bit of well thought out modification won't fix.

I agree on the quality of the chassis, cheap bearings, thin dogbones, weak servo, etc.
However the design is loosely based on the LRP S10 TC which is a very capable on-road chassis in Europe.
The LRP comes with a lot more adjust-ability and tune-ability than the HSP though, CVDs, slipper clutch, stabiliser bars, more shock mounting points, etc.


Video coming soon, it was still about 36°c when I got home late night at 6:30pm :wtf:

marshun
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Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby marshun » Tue Feb 12, 2013 12:27 am

thats seriously awesome. these are the kinds of mods i like seeing. bravo

mx_masta
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Mon Feb 18, 2013 8:04 am

Sorry guys, the video will have to wait a while longer.

I attended my first comp on Sunday, I broke one of my CVD's in my driveway on Saturday afternoon and the other one during practice on Sunday.
So I had to use standard dog-bones during the comp which was frustrating because I could not hold good angle.
Also I had a loose screw on one of my caster links during practice and my qualifying run (my own fault for rushing on Sunday morning)
And I never got around to properly locking my rear diff, I just repacked it with HP grease a few months ago.
I know that sounds like a lot of excuses but I wouldn't have done much better anyway seeing as how it was my first comp and I was hella nervous.

I believe the failure is due to me adding rubber o-rings as a pin retainer on the CVD's as the pins were tending to loosen and I had no thread lock liquid.
I think this added some drag and heat on the CVD which caused the failure.

Replacements are ordered (2 sets) if these do not hold up well I'll bight the bullet and upgrade to OFNA LD3 or HPI RS4 nitro 3 ones, big price difference though!
Also the locked rear diff from my other chassis will go in, so hopefully I'll get around to making that video in a few weeks.

mx_masta
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Wed Mar 20, 2013 4:38 pm

Well the HSP CVD shafts are not holding up well at the >45°steering angle that I'm getting.

So I'm on the hunt for a decently priced set of shafts with 52-55mm pin centres, any ideas.
I've looked into the HPI RS4 ones I mentioned above but I think they are too short.
Similar story for the LD3 ones without a front diff swap, but they are closer to the required length, can anyone confirm the exact pin centre length of the shafts for me?

mx_masta
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Thu Mar 21, 2013 6:56 pm

So I bit the bullet and ordered a set of the LD3 shafts since I know that they'll fit.
With the amount of camber I'm running the HSP shafts are right near the bottom of the cup anyway so they should be fine.

I've also ordered another set of the HSP shafts since they'll most likely get to me first so at least I can use my RC without having to swap in my spare dogbones (YUK!)

As a side note, when the shafts are good this mod makes a massive difference to the control of the car, much less tendance to spin out mid corner.
I also swapped in a bluebrid 631 servo which also made a huge difference in transitions.

Once I have it all running right I promise I'll post that vid ;)

lee180784
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Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby lee180784 » Tue Apr 30, 2013 10:24 am

Hi just done this mod all good so far just put plenty of Grease on driveshafts and cups and turn the steering down a bit on controll so you just get under 45 angle and it is all good

mx_masta
Rally Style Drifting
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Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Fri Jun 07, 2013 1:34 am

Quick update, the OFNA LD3 shafts have been working fine for ages now, no more breaking shafts.

However they do start to chatter just before 45° but that's easily avoided with my controller.
The chassis is still 50:50 so I don't really need more than that anyway.

Even if I do CS it it will only be minor with both on HPI or AXIAL gears since I don't want to hack the diff housing.

Sorry for the lack of video, no excuse just been having too much fun driving it to think about pointing a camera.

mx_masta
Rally Style Drifting
Rally Style Drifting
Posts: 23
Joined: Sat Nov 03, 2012 5:45 pm
Drift Chassis: HSP Flying Fish
Location: Perth; Western Australia

Re: Proper HSP steering upgrade, zero Ackermann & c-hub delete.

Postby mx_masta » Fri Jun 07, 2013 1:35 am

Quick update, the OFNA LD3 shafts have been working fine for ages now, no more breaking shafts.

However they do start to chatter just before 45° but that's easily avoided with my controller.
The chassis is still 50:50 so I don't really need more than that anyway.

Even if I do CS it it will only be minor with bolt-on HPI or AXIAL gears since I don't want to hack the diff housing.

Sorry for the lack of video, no excuse just been having too much fun driving it to think about pointing a camera.


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