Kronos XTR Horatio's XTR Build

[Horatio]

They don’t seem to, you need to message them through Facebook messenger. Maybe steal/borrow someone else phone for a bit. Or I could maybe drop them a message for you maybe chat by email or some other way if you’d like.

Here’s their contact info & couple reviews & pics.

You absolute Ninja! They do look good, don't they! Love the tool station.

I'd love it if they could make a shadow board, too.

 

[Nelson.81]

You absolute Ninja! They do look good, don't they! Love the tool station.

I'd love it if they could make a shadow board, too.

Try there email if no reply maybe have someone you know message them through Facebook. I don’t know anyone who used them so proceed with caution lot of scam sites out there, looks legit though would be a strange hustle but people try anything. But seem uk based, a lot of agami stuff may even be somehow affiliated with nemo .

 

[Horatio]

Well I've accidentally upgraded my shock stand-offs.

I'd ordered some Scorched bits and these were sent instead of M3 & M4 counter sink bits.

These aren't designed for Corally rigs, but were easily adapted by:

• using M4 x 30 cap head screws (with no shoulder - threaded all the way)
• drilling out the plastic top-hat bush with a 4.8mm drill bit.
• using M4 washers - one for each stand-off

I've got a neat little radio box, with a waterproof o-ring all the way around and a grommet. (Don't even think about another lawsuit Traxass....you didn't invent O-rings, radio boxes or grommets).

It's neat, lower profile - but doesn't have an antenna mount, so will be modified accordingly.

The Scorched parts servo mount is a thing of beauty - so much firmer and lower profile:

Easy to mount - the servo can now be mounted closer to the steering assembly with a shorter linkage and not on the wonk. Better!

Working on the rears now - I'm currently out of stock of M4 x 30 cap heads, though my Baja 5B uses these.

Nice distraction from the reality of hacking up a perfectly good piece of carbon fibre....

 

[Horatio]

The cutting begins.

Coping saws, hacksaws = way too slow.

Diamond cutting disc on 125watt 37000rpm Dremel is the way.

I've done about 20% of the cutting and I wasn't going to start it til Saturday, so I feel ahead of the curve.

CNC would be more precise, but this is literally hand made one-off, honed with grit and determination. Perhaps a little swearing every now and again.

Questions like why's the vacuum cleaner gone off again, and what's the point of dust masks if they steam up your glasses? 100% more likely to lop a finger off if you can't see.

 

[Nelson.81]

View attachment 6917

The cutting begins.

Coping saws, hacksaws = way too slow.

Diamond cutting disc on 125watt 37000rpm Dremel is the way.

I've done about 20% of the cutting and I wasn't going to start it til Saturday, so I feel ahead of the curve.

CNC would be more precise, but this is literally hand made one-off, honed with grit and determination. Perhaps a little swearing every now and again.

Questions like why's the vacuum cleaner gone off again, and what's the point of dust masks if they steam up your glasses? 100% more likely to lop a finger off if you can't see.

Coming along nicely, good job considering your using a dremel don’t know how you’ve kept it so straight, I’d butcher it with a dremel, id have gone for a router drill but not everyone got that in the toolbox but looking good. probably be done before my build it’s come to a halt lately, soldering esc holding mine up but get it done this weekend hopefully, get it over finish line.

 

[Horatio]

This is the undrilled/unmilled weight.

To be honest, with it being so thick, I can't believe it's lighter.

No braces required!

 

[Horatio]

Happy with the quality of the cut.

Here's the fabricated part to alter the angle of the steering plate, cut from Dupont Nylon carbon composite.

If we ignore the fact I started countersinking the wrong side of the chassis, good progress has been made over the weekend and the 'wide boy XTR' should be ready this week.

6S to start with.

 

[VaporTrail]

Horrible geeky maths time.

I'll spare the calculations and just give the results.

FRONT

The front driveshaft has a stock length of:
85mm (Hypotenuse)
Angle: (12.0°)
This gives us a triangle:
View attachment 6881

A=17.7mm (distance motor mount needs to move over to centre driveline)
B=83.1mm (new driveshaft length)
C=85.0mm (stock driveshaft length)

Shaft length can decrease by 2mm

REAR

The rear driveshaft has a stock length of:
175mm (Hypotenuse)
Angle: 5.8°
This gives a triangle:
View attachment 6882
A=17.7mm
B=174.1mm
C=175.0mm

Shaft length can decrease by 1mm.

Conclusion:

Total driveshaft lengths (when added together) need to equal as close to 257mm as possible.

Motor mount would then have to move rearwards by as much as 6mm, with corresponding 6mm longer front driveshaft - from 83 to 89mm.

The disadvantage of moving the motor rearwards is less space for longer can motors and more rearward weight bias, but these are comparative minor points compared with power robbing, 12° driveline angles.

In full size vehicles, these angles are not recommended to exceed >2°!!

The planned modifications are not subtle, and whilst I want to endeavour to keep the Kronos XTR's inherent handling characteristics, already I'm seeing reasons where certain trades have to be made for the best quality components.

Principally, weight distribution and kick-up.

These are minor trades to make for lower weight, less rotating mass, greater efficiency and greater stiffness.

I'm gonna have to double check my Shogun when I get home. Is that the front driveline angle? Good gravy, it looks absolutely terrible when you zoom in like that.

 

[Horatio]

I'm gonna have to double check my Shogun when I get home. Is that the front driveline angle? Good gravy, it looks absolutely terrible when you zoom in like that.

Yeah, it's quite extreme on the Kronos/XTR. There was a no compromise on the weight distribution - they wanted the weight further forward than the Kraton. Mission accomplished.

The trouble is, it's horribly in-efficient and causes increased rates of wear.

They remedied it to an extent when they brought in the Kagama. They moved it all back, reducing the angle, but compromised the weight distribution.

Mine on the other hand will be zero angle and no kick up - which will increase power and efficiency for speed runs and drag.

I'm hoping the lack of kick up doesn't compromise the off road performance. We'll find out soon enough!

 

[Horatio]

I was dreading DIY milling the chassis - without a mill. But it's turned out good.

Outstanding quality of Scorched parts. Milspec quality in RC!

Assembly with anti vibration washers. Think serrated wheel nuts - but in an M3 washer.

2.1 mm relief for crown wheel.

Servo to be transverse mounted, moved forward and towards the centre. The really nice thing about this is how much more solid the mount is (zero flex), the improved weight distribution and crucially - a greater mechanical advantage over the steering bell crank.

Transmissions fit nicely, steering assembly meets with the countersunk holes in the chassis - next up - motor mount, battery mount.

Fun fact: This XTR 'wide boy' chassis is 10% wider - but affords 100% more mounting space.

This means I'm looking at larger ESC''s and space for a second battery.

TP motors look interesting.......

 

[VaporTrail]

looks absolutely amazing! I'm assuming the lack of kick may affect it somewhat offroad, mostly the bumps and jumps.

looks like it's coming together nicely, though. Amazing job!!

And interesting note about the weight bias. Perhaps that's why for as heavy of a platform as the Corally is, it actually performs quite decent considering most would classify it as an entry level basher.

 

[Nelson.81]

View attachment 6974
I was dreading DIY milling the chassis - without a mill. But it's turned out good.

View attachment 6975
Outstanding quality of Scorched parts. Milspec quality in RC!
View attachment 6976
Assembly with anti vibration washers. Think serrated wheel nuts - but in an M3 washer.
View attachment 6977
2.1 mm relief for crown wheel.
View attachment 6978
Servo to be transverse mounted, moved forward and towards the centre. The really nice thing about this is how much more solid the mount is (zero flex), the improved weight distribution and crucially - a greater mechanical advantage over the steering bell crank.
View attachment 6979
Transmissions fit nicely, steering assembly meets with the countersunk holes in the chassis - next up - motor mount, battery mount.

Fun fact: This XTR 'wide boy' chassis is 10% wider - but affords 100% more mounting space.

This means I'm looking at larger ESC''s and space for a second battery.

TP motors look interesting.......

Lots of room beside servo for a big esc now ,keep other side free for batteries, id maybe look at xerun combo if want keep weight down, 6s crank timing & boost up. But came across this different brand esc on a channel. This mad max20 a big unit, there also a max10 does 12s also but can’t find any vids on it. Kilowatt rc only place I seen them run he a few vids about them. Probably best stick with hobbywing or castle pair with a tp power motor but nice see something new on market. But looking good coming together faster than mine

 

[Horatio]

looks absolutely amazing! I'm assuming the lack of kick may affect it somewhat offroad, mostly the bumps and jumps.

looks like it's coming together nicely, though. Amazing job!!

And interesting note about the weight bias. Perhaps that's why for as heavy of a platform as the Corally is, it actually performs quite decent considering most would classify it as an entry level basher.

I understand kick up tends to be more useful on 2WD cars to 'encourage' easier weight transfer to the front. Typical kick up angle 6° - 10°.

On 4WD off road cars, kick up tends to be 1 - 7°, which is much less, primarily because 4WD cars tend to have more central weight distribution AND because greater angles interfere with front drive.

On road cars usually have 0° or anti-dive, which is the inverse of kick-up, where the angle of the arms lean forward.

Off road, kick is supposed to aid bump handling and 'sub optimal' landings (lawn darting).

My T2E has hardly any kick up - 1 - 2°.

The loss of 6° kick up is also a reduction of 6° caster, so I've placed the spacers in front of the upper arms.

 

[VaporTrail]

Hmm...sounds like you'll be alright then my brother. Maybe just a small wedge to get a couple of degrees? Or if the Kronos will be a speed demon for the rest of its days, then I say forgo the kick altogether.

Either which way, it's pretty awesome to see some custom work being done.

 

[Horatio]

Progress is being made - but by burning the midnight oil. Configured for running 6S, very comfortably. But as you can see, there's room for a very tasty ESC.

The radio box is being replaced with another Hobao item - the current one is big enough to fit the receiver, but not big enough to plug anything into it. Whoops!

Centre diff, front and rear transmissions now all fitted. Battery mount and buckles all sorted. Servo alignment will be longitudinal now having done some feasibility tests.

Droop - I didn't want to reduce the tunability here - being able to add or take away droop is handy and I still want this rig to work off road on grass and astro.

So, rather than file the carbon chassis with a camber (like on the 7075 chassis), I recessed the the area where the dome head sits in the arms. Bingo! Works perfect. I have exactly the same droop setting as I had before.

This should all be together (properly) by tomorrow night. All the plastic protection film should be off too, although I am really quite liking the blue carbon look and will miss it.

It's been a great build so far and whilst I have not compromised the materials, it's only been a fraction of the cost of a kit.

A shout out to Scorched parts - absolutely faultless components. As you can see, there are some Arrma Kraton influences on my XTR - but that's OK - because everyone loves Arrma - even us lot!

 

[VaporTrail]

looking well-sorted! Definitely looks like it's been quite the involved task.

and as a side note, my dremel looks exactly the same!

 

[Sandracer_NL]

Great looking build!

 

[Horatio]

The big reveal......

This is the weight of the rig minus - wheels, ESC and battery. Either way, it's pretty darned light - and clean.

It's a nice, straightforward, no fuss layout. The Scorched parts really add a touch of class about the rig.

I hope that this example opens some new doors......

 

[Sandracer_NL]

With wheels and body you probably saved little over 0.5KG which is quite a lot. And it looks great!

 

[Nelson.81]

Awesome job, I don’t think I could stop at just the chassis, needs shock towers, top deck ,upper arms inserts(just because look good) carbon everything now see how light can make it. Was thinking of adu battery tray but quite like that scorched 1 .

Now go get it dirty making me feel bad leaving mine on the bench all dirty, it’s up & running now .still got Bodies to paint & few teething issues to sort but she runs, I’ll clean it later maybe post an update if get time.