New S.O.S Micro racer prototypes parts

[SOSx]

Well after the first test at the weekend i thought it about time we put up a thread about some new parts we've been working on for the current micro racers (Carisma GTB, losi mini 8 and hopefully soon to be LC racing). Please excuse the phone photo quality!!

I should note here that we could produce these for other makes of cars in batches if they were wanted We would just need a fesh new part to make the drawings from sent to us.

First up is our Super heavey duty grade 7075 T6 Aluminium alloy or Ti6al4v Titanium Alloy re-enforced carbon fibre shock towers.



First up for the Carisma GTB



Next up for the Mini 8



These one's shown on our cars are made from 1.2mm Titanium () rebated and resin fixed into 3mm pure carbon fibre. Matt/Scattyv (who to be fair has put the majority of the work into these new products) had the orginal mk1 prototype of these on his car for over 9months and many hundreds of hours of racing/crashing. To the point that the carbon fibre had broken in many places yet the tower held together and stayed strait. In the same period of time Brimmers (the 3rd part of S.O.S) went through a fair no. (4-6) of carbon towers in the same time from no worse crashes than Matt.

We have altered the profiles of both towers.
In the case of the GTB the changes are for aero rounding the top profile to smooth airflow and also as the alloy/carbon composites are stronger we feel it safe to increase the central hole to aid airflow onto the cab increasing front down force. These also have the extra shock and caber link positions as our standard carbon towers.

In the case of the Mini 8 towers the alterations were pretty much the oposite. increasing the top radius and side profiles of the towers so as to make them stronger and more resiliant in this area that takes all the load the hole for airflow is already quite large so was no need to change.

Realistically we will be looking to do small production runs with 1.6mm 7075 T6 Alloy inserts as this will allow us to keep a "relatively" low sale price of £15-20, TBC once we have the production costing sorted.
I think we would probably only offer the titanium versions if a batch was ordered as the cutting time for the Titanium is many times that of the 7075 t6 and as such they would be more expensive.

[SOSx]

Full details tomorrow/later
We've also cut a first prototype set of 6082 T6 aluminium alloy hinge pin hangers for the Carisma GTB. These utilise the Losi mini 8 inserts to allow both tow in and anti squat adjustment. Also as they do not need to be so large/cumbersome they can offer an interesting tuning aid of +-1.6mm wheel base adjusment from stock as is (but may be able to up this to+-2 with more development

Night

[SOSx]

So Aluminum hinge pin holders for the GTB.

These are the Mk 1 prototypes so have just had a quick De-bur and sanded back rather than a full surface finish (polish or anodising not sure which yet). Also the holes for removing the inserts were hand drilled as an after thought. On the final product they would be cnc machined and nice and central.

Rear pair first - These provide rear toe adjustment from -1.5 degrees to -3.5 degrees and anti squat adjustment +-1 degree from stock antisquat (As per mini 8 settings sheet). Also due to not needing to be so deep we are able to provide wheel base adjustment by +-1.6mm from stock (but hopefully with some design adjustments we can get this to +-2mm from stock). Which out of interest is still BRCA legal.






Next the front hanger - this is only for the front and doesn't contain inserts. This is more for strength really (I've bent the standard in a crash) but we could have separate options available with different kick up/caster angles. We don't expect to do the rear hanger for the front at the moment but this may change

[SOSx]

Next prototype off the cnc this afternoon are 7075 T6 alloy chassis for the GTB . This again is just a basic rough prototype with minimal finishing (a light sanding with 1500 & 3000grit). I will be fitting it on my car and testing it at the weekend.



I'm unsure what the flex level will be, but if I find I need more flex we are prepared to start milling pockets out of the top side . This could also have add benefits of allowing me to lower the full electrics install in places reducing cog. We are looking at the process of hard anodizing them in house as well but we will see about this.

I have not had a chance to accurately weigh all the new parts but safe to say the alloy components could add a bit of much needed weight low down.

If there was interest in these we would be looking to sell them at a very reasonable price somewhere around £25.

And before I forget if thermal past is used between the motor and alloy motor mount and alloy motor mount and chassis I think it should aid with thermal management somewhat increasing the heat sink area quite drastically. I will check this at the weekend also.

[SOSx]

Ooh I did forget that it has 2 extra servo mounting holes pre drilled suitable for the slightly larger servos such as the very popular Savox SH1257MG.

[silone74]

Did the chassis get tested or is it still awaiting test



Cheers Si

[SOSx]

Hi Silone,

I have ran it for a single race day so far, but want to do more handling testing. Intial impressions are good with the car feeling great - more stable in high speed sections and generally less twitchy. But it was not an entirely accuarate test as I was also running the car with the alloy hangers (which need more testing them selves) and to give an accurate representation I need to run the car without these to see what just the chassis is doing on it's own.

One point that I particularly wanted to investigate with the alloy chassis was the potential for effective heatsinking. And it seems that if the chassis is connected thermally to the motor it can make quite a drastic difference to the runnning temps. To provide good thermal connection I use the alloy motor mount with good qualitiy thermal paste applied from motor to motor mount and motor mount to chassis.

I run a fairly hot motor and esc system (Novak 380 13.5T (6000Kv) motor hooked upto a Dual Sky, 150a XC850 TFMJ with moderate boost/timing advance applied). Normally with my carbon chassis installed my motor temps would run consistantly at about 55-60 degrees C after a 5 min heat and 65-70 after a 7min main. With the Alloy chassis installed I was consistantly seeing a drop of 10-15 degrees at just 45-50 degrees c after a 5 min heat and 50-55 after the final. The chassis itself was getting upto 40-45 degrees at the point where the mount attached to the chassis!

The protoype adds 31g to the weight (which certainly lowers your cog). But this may change as i'm insterested in trying a couple of other chassis profiles and possibly topside milling of pockets to induce different flex charicteristics and weight ballance.

[silone74]

Look forwards to seeing the full results of the testing, it is good to see an actual test in progress, the profile and milling options is interesting and deciding the area to mill out, if the area where the esc sits was to be milled do you think the ezrun style of esc would fit under the top deck with out the need to trim the fins on the heatsink, hope u don't mind the questions.


Si

[SOSx]

Hi Silone,

No don't mind the questions
I would like to try narrowing the rear section of the chassis to possibly induce a little more flex, hopefully allowing a little more weight transfer over the rear axle.

Also I would like try lowering the electronics by opening up 1mm deep pockets around the esc,motor and battery. I don't own any Ezrun ESC's anymore so couldn't tell you if 1mm is enough of a difference to allow them to fit! What dept are they? I would also like to consider weight balance if i do this as it could be aid in getting the correct balance without adding so much weight.

Another option worth considering is a slightly extended wheel base as there is a few mm allowance to meet maximum size for the category. This may be a different method to stabilize the car in high speed sections (which in my opinion has always been the GTB's main problem as the font end is really quite pointy/aggressive and the rear end is a bit loose as standard).

Will keep you all informed.

If there are any racers out there who may be interested in beta testing at a reduced purchase cost please get in contact

[mrspeedy]

Have you thought about making any parts for the EMB-1 ? Its growing in popularity but could do with some upgrades ... rear end front hangers with a little less anti squat spring to mind

[silone74]

Looking at the chassis and motor placement the motor has a over hang from it, do you think making the chassis wider at that point would give better protection, the stock body is shaped that way so I could see it covering the chassis if it was shaped in the same fashion, maybe wider at both sided to keep it looking symmetrical?


Si

[SOSx]

Hi si (mr speedy) - We do produce a few bits for the emb-1 (carbon towers, top deck and ball raced bell crank). We would do more but it's a car that none of us own to be able to do the testing on. The only reason we did those is we had a local guy who bought one and fancied the bits. But hew has since moved to China

Could be interested in doing a deal regarding some free test parts if you were interested in sending us car/parts for working from. You would then be in a position to feedback the test results for us as well?

Si - We've been talking about the GTB chassis options a fair bit and what I would really like to do is produce is a slightly longer chassis in 2mm alloy with machined pockets that could accept the losi side guards.
This way you would not need to widen the chassis to provide protection for the electronics which I think is better.

But the main issue comes with providing a new body for it (Si). The standard body just wouldn't work the way it narrows at the front. And as far as I can tell none of the other standard micro Phat bodies fit over the motor (although I could be wrong?). The other option I've considered is designing some 3d printable side guards that would work with the standard body, but they would be more expensive for people than the standard losi ones and a new body.
I'm definitely going to try a longer chassis and we will se what we can do with side guards.

[silone74]

I have SOS towers on my EMB, I like cf I also have cf towers on my m8.
I think some kind of guard or wider part of the chassis is needed just to give some protection on the esc/motor side.
Has any one tried running the esc on the top mount that the rx is on and putting the rx down there as I do with both m8 and EMB , would it be too top heavy, I might give it a go and see how it performs

[Karting]

Why run anything on the top deck?



It all fits (Not even a micro sized reciever)

[silone74]

Any news



Si

[SOSx]

Hi Si,

Would of replied over the weekend but was busy cutting a new prototype extended alloy chassis.



This will give an adjustble wheelbase from 187-190mm (maximum allowable). It still needs testing and a few tweeks to the cut files but I'm confident it has has potential! The chassis has a slightly changed rear profile as well as pockets machined into the upper surface to allow more lateral flex (which hopefully will aid better weight transfer/traction in slow speed corners. If we decide to produce them we will have the 7075 hard anodised so surface resistance will be top quailty.

The chassis has 6mm extra space for the electronics install which should make for more flexibilty in esc and servo layouts, which if your like me and like to run a 380 sensored motor is a big plus. I have also added extra servo mount holes which suit the slightly larger popular servos like savox SH1257. Another benefit in the electronics install is that the popular micro recievers should all fit on the bottom deck allong with the popular turnigy 2200 traxxas style packs (TRA2820).

The pockets are also designed to both keep overall weight down and help ballance the electronics layout out. My aim is that no no front battery weight will be required with this setup.

The final beneift that I am extremly happy with the performance of is temps (I know i've mentioned it)! I really am suprised at the drastic improvment over the carbon chassis easily 10-15 degree's drop after a 5 min heat.

[silone74]

Thats great and I am liking the dog too lol, how long do you think a realistic time scale for production, having said that I am laid up with broken legs so I ask for every one else interested


Si

[SOSx]

Hi Si,

Lol, was putting things together saturday night after cutting it saturday afternoon and the only bit of paper i could find was one my 5 year old daughter had been drawing on

As for production schedule? Well I don't even know if it will go into production yet as it still needs testing. But if it works as i have designed it to then it I would still expect at least a month before a batch is ready for sale.

The new longer test Belts (Bando) wont be here until late next week
and I still have to cut an extended top deck and new battery strap.
Were also busy working on a new tumbler for finishing Alloy products before hard anodising so that alloy batches require less labour than they do currently.

Infact what are peoples prefered anosied finish. My preference would be natural "hard" anodising for maximum strength rather than a thinner coloured finish? I think I may start a poll as to what sort of anodised finish people most prefer.

[SOSx]

Well the Bando Belts turned up yesterday. So after work I finished cutting the new braces/top decks and battery strap, put it back together and went for a drive. As always excuse the photo quality









I am really happy with the amount of space for the electronics now, there is enough room for a no. of different esc and servo combinations. Also having the reciever in this position works really well as the wiring can be fed through the top deck nice and neatly. If I decide to stick with this chassis I will trim all my wiring down to suite giving a very neat wiring solution.

I need to get some new scales so that I can check the weight distribution
accurately but I am fairly confident that it will be closer than before. Currently I'm running the completely overkill 150a Dualsky XC850TF + novak 380 (6000Kv) which does add an extra 14g over the "standard" EZrun 60a + stock motors that many people use. I might swap this esc for my reventon pro as it will bring that down to 7g difference to the hobbywing and also remove the switch and switch wire from the equation. For a sensored setup i actually think the 60a Dualsky XC550 would be perfect and is only 3g heavier than the hobbywing/carisma combo.

Also I am happy with the amount of lateral flex in the chassis more than both the carbon and un-pocketed alloy chassis. I would say just slightly stiffer than the stock fiberboard laterally but a fair bit stiffer longitudinally and this is just about where i wanted it to be.

As for the stock body, I would say it actually fits better than on the stock chassis. Less over hang at the rear for dirt to get in. Ream one new hole at the rear and your all good.

I only ran a single pack through it last night as it was getting dark but I must say it felt very composed and wasn't far of keeping up with my Brimz 22-4

[silone74]

Thats looking great, after you have done more testing and if this was to be put into production would you sell as a kit with chassis, belt, top deck and battery strap and anything needed to swap over?

The milled out sections I can see making a big difference, the little protection on the esc, motor side still bugs me abit