£100 speed challenge (Project Ender) TARGET 100MPH!

[Alex97]

As the title suggests I'm going to attempt to build 100mph RC while sticking to a tight £100ish budget. This was done a few years ago and I believe some people got into the high 80mphs. In the last few years there's been a surge of ok electronics hit the market at a very low price which should help plus hopefully the engineering degree will come in hany(cost enough).  I've always fancied trying to join the 100mph RC club however I've never had the time for patients to try it. 

 

The goal is to keep this as simple as possible-

 

Chassis - 1.5mm thick aluminium sheet 70x450mm. I'll be using right angle strips to help support it.

Drivetrain and steering - Mardave S210 project kit. This includes everything that you need other than a chassis or body mounts, perfect for this project.

Electrics - 3-4t brushless motor, 120a ESC, cheap digital servo, 2 or 3s lipo

Body - the joys of having a 3d printer means that I'm able to design and print my own body at very little cost. I've started modelling up a few things just ideally I need the chassis to start measuring things

Wheels and tires - TBC 

 

Items excluded from the budget-

 

- Battery

- RX 

- Screw, nuts, pinions and washers

- Wheels and Tires

 

This is the stuff that I've already got so I don't want to class it. 

 

 

Running budget...

 

- Chassis Material £6.33 

- Mardave V210 £34.99

- ESC Hobbywing 120BL £38.99

- Motor 3.5t trackstar £28.16

- Servo 22g metal geared £6.43

- Any Extras TBC

 

 

Total £114.90

 

Remaining -£14.90

 

 

This might completely flop however at least I've documented it for the whole internet to see 😂

Edited July 10, 2020 by Alex97

[Ninetiesbeard]

One word; Doable. If youre crafty with it, thatll do it. Id use a hobbywing esc for the cheapness

[pieman5]

Yeah this was done a few years ago, I remember me and Bez both running 2s dragsters we built.

 

I think i did mid 70's and Bez managed 83. 

 

I bought a used associated LC12L4 for £24.02, a New Beeman X8 150a esc (hobbywing clone) for £34.53, a used sirius 9000kv motor for £24 and a 5200mah 30c 2s for £12.97.

 

I used some scrap L channel aluminium to make the chassis and had about £5 so i bought some thin lexan sheet to make the shell.

 

Where are you planning on running the project?

 

Be interesting to see what you come up with, let me know if you want any help/advice 👍

 

Edited June 8, 2020 by pieman5

[Alex97]

38 minutes ago, pieman5 said:

Yeah this was done a few years ago, I remember me and Bez both running 2s dragsters we built.

 

I think i did mid 70's and Bez managed 83. 

 

I bought a used associated LC12L4 for £24.02, a New Beeman X8 150a esc (hobbywing clone) for £34.53, a used sirius 9000kv motor for £24 and a 5200mah 30c 2s for £12.97.

 

I used some scrap L channel aluminium to make the chassis and had about £5 so i bought some thin lexan sheet to make the shell.

 

Where are you planning on running the project?

 

Be interesting to see what you come up with, let me know if you want any help/advice 👍

 

Much appreciated mate, 

 

Currently I'm not sure where it will be run however I'll no doubt find a good stright to give it ago. 

 

The material is dirt cheap, the 70*450mm sheet was £1.34 so I'll be using that. The Mardave spur is 46t so I should be able to run a bigish pinion which should help. I've seen a 3t brushless motor for £20 which I'm tempted to pick up. I'm not sure what ESC I'll be using but my main goal is to get the body work and chassis finished. 

 

I'm thinking about trying to do a DRS system to help slow things down. 

Edited June 8, 2020 by Alex97

[Ag100]

Sounds interesting, will keep an eye on this.

with these high speed cars, do you fix the steering when doing the runs?

[Alex97]

4 minutes ago, Ag100 said:

Sounds interesting, will keep an eye on this.

with these high speed cars, do you fix the steering when doing the runs?

TBC

[pieman5]

Yeah always good to have the chassis built up first. 3d printed shell will be good to see. 

 

I tried one once on a buggy but crashed it before i really had chance to see how it actually performed.

 

Have you seen Bez's "Chaser" project? He printed the whole shell and it was very successful, could give you some ideas.

 

8 minutes ago, Ag100 said:

Sounds interesting, will keep an eye on this.

with these high speed cars, do you fix the steering when doing the runs?

 

Ive never seen anyone run with it completely locked. It varies between everyone but personally depending on which car im running i turn my dual rate down to between 35-15%

 

Ideally through enough testing it will run straight with very little correction but keeping the dual rate low means you can still steer in a controlled manor without throwing the car completely off course.

[Alex97]

41 minutes ago, pieman5 said:

Yeah always good to have the chassis built up first. 3d printed shell will be good to see. 

 

I tried one once on a buggy but crashed it before i really had chance to see how it actually performed.

 

Have you seen Bez's "Chaser" project? He printed the whole shell and it was very successful, could give you some ideas.

That was part of the inspiration for this.  

 

Plan is to build the chassis, teach myself about aero dynamics, source the electronics and then run. Easy! 

 

 

I'm planning on making the motor mount and steering setup on plates so that the underside of the chassis is completely flat. 

 

 

 

[Alex97]

This is a first mock up of what things might look like...

 

 

I've designed it so that there's a 30x1.5mm strip that runs down the centre line of the chassis, which is why the front of the body has been desgined to push as much as under it as  it can without adding too much drag. . This should hopefully force air through the chassis and help create downwards pressure. At the rear of the car i'll be adding a defuser to keep the rear of the car planted as total weight will be around 1kg so i'll be needing a some downforce to stop it from taking off! I've tried to show how this will work... 

 

 

By having this area of high presure along the whole chassis it should make the car less unperdicable as the faster it goes the higher the presure = more downwards forces (vacum) 

Edited June 9, 2020 by Alex97

[Ag100]

Interesting design, front end kind of looks like the old Advanced Passenger Train.

 

is their any merit in copying the real world land speed cars shapes like the Thrust SSC or Bloodhound, I know these are designed around jet engines, but the shapes are obviously optimised for aero?

[Alex97]

2 minutes ago, Ag100 said:

Interesting design, front end kind of looks like the old Advanced Passenger Train.

 

is their any merit in copying the real world land speed cars shapes like the Thrust SSC or Bloodhound, I know these are designed around jet engines, but the shapes are obviously optimised for aero?

It's still an option however I want to maximize air flow under the car. 

 

I might try and point it in a little more however looking on the Rossa Facebook page they all seem to go for the flat front rather than a pointed one. 

 

The record holder does have a pointed one so I might give it a try or try and taper it in from the side. 

[Alex97]

7 hours ago, Ag100 said:

Interesting design, front end kind of looks like the old Advanced Passenger Train.

 

is their any merit in copying the real world land speed cars shapes like the Thrust SSC or Bloodhound, I know these are designed around jet engines, but the shapes are obviously optimised for aero?

 

i mocked this up this evening...

 

 

i've gone for a rounder front end however i've tried to use a F1 front wing thumb design. 

[Ag100]

Looks good, a couple of NACA ducts underneath perhaps to get some airflow across the Motor to help with temps?

[Alex97]

The bodywork work won't change my more after this... 

 

 

 

i'm hoping that I don't need to make the rear end higher as there's only 40mm in heigh to however I reckon i'll need to increase it slighly where the motor sits 

[Alex97]

The chassis has been made and is now setting. For now I've just used epoxy however it will be he'd in place using nuts and bolts. 

 

The hardware store had run out of 3mm drill bits so I'll need to try and find some over the weekend but I did pick up a counter sink drill end to help keep everything flush. 

 

 

 

 

Although I'm happy with the body I think I'll get the mechanical parts working first before I start printing the body as it will take about 50 hours to print the whole body then another 10 hours for the mounts and supports. Currently the end is just open but I'm thinking of adding something to close it in. 

Edited June 12, 2020 by Alex97

[Alex97]

Update on the chassis above, the epoxy never set correctly and for the cost I'm not going to risk running it. I've ordered new epoxy and chassis materials so hopefully they should arrive within a few days. 

[JoeMower]

This is totally my sorta thing. I just joined the forum to follow this thread. I have started speed runs but with a Tt01, wanna go down the custom chassis route, and thought a mardave would be a perfect doner. You said you bought the Mardave S210? I can’t find this? Do you have a link?  I just need the rear motor/Axel mount, and the front wishbones and hubs.  Any ideas would be great. 

[RCbutcher]

Brilliant idea mate I'm interested to follow. Have you seen the new goolrc combos like a max8 esc for £36 ish. Seems mental 150a wp esc they could be the new hobbywing on value since hobbywing went all mainstream lol. 

[pieman5]

2 hours ago, JoeMower said:

This is totally my sorta thing. I just joined the forum to follow this thread. I have started speed runs but with a Tt01, wanna go down the custom chassis route, and thought a mardave would be a perfect doner. You said you bought the Mardave S210? I can’t find this? Do you have a link?  I just need the rear motor/Axel mount, and the front wishbones and hubs.  Any ideas would be great. 

 

Here you go:

 

https://www.mardave.co.uk/rc-cars/94-detail

[JoeMower]

That’s awesome, thank you so much!

 

i currently have a 120amp esc, 5200kv motor, and 2s. So with some tall gearing could get some serious speed. I have never owned a mardave, are the motor mounts adjustable? Or do only curtain combo’s of gears mech probably do you know? 

[Alex97]

8 hours ago, RCbutcher said:

Brilliant idea mate I'm interested to follow. Have you seen the new goolrc combos like a max8 esc for £36 ish. Seems mental 150a wp esc they could be the new hobbywing on value since hobbywing went all mainstream lol. 

It's something that I'll most certainly be looking I to however that's a month or so away before I start buying electronics. 

 

 

[Alex97]

1 hour ago, JoeMower said:

That’s awesome, thank you so much!

 

i currently have a 120amp esc, 5200kv motor, and 2s. So with some tall gearing could get some serious speed. I have never owned a mardave, are the motor mounts adjustable? Or do only curtain combo’s of gears mech probably do you know? 

It's adjustable, if I was to do this again I'd have most likely made my own motor mount and then had the shaft machined to 5mm so I could run the better range of gearing and get close to 1/1. 

 

It's a good starter kit for £34.99 however if you were throwing lots of money at it then there's much better options out there. 

[JoeMower]

Running 1:1 really doesn’t work, get a lot of cogging unless your running a low Kv. I run 5.11 to 1 at the moment and getting 60mph easy. 

 

I am having second thoughts on using mardave as a base, lack of suspension options is what’s limiting it. As no super smooth surfaces around me 😕 

[Paul Busby]

This is a cool idea man.

When my CNC arrives I might try and join in on this endeavour and do something of my own as a learning experience [emoji1]

Interesting ideas with the aero as well, only point I would make about the "thumb" is that it was done like this for safety. The regulations dictate the maximum height and surface area for the front of the car, I think give the option, a lot of teams would be more angular and pointy.

if you go back to before they introduced these rules, all the cars had very high noses that suspended the wing and forced air under the car.
Obviously you can imagine the danger if one of those high noses were to slide over the top of another car towards the cockpit [emoji43]

[Alex97]

Body work has been finished, it will be made up of 6 different pieces(7 if you count the rear floor). 

 

I had to extend the rear section a bit however I don't think that it looks too bad as the rear wing blends in with it. 

 

 

 

I was going to paint black PETG however after doing further research it would seem like it's going to be easier to print it in the final colour. I'm currently between two colours, orange and yellow (please vote in the pole at the top). 

 

the whole body is coming in at around 500g and the raw chassis is around 300g. Once I add the electronics and moving parts i reckon it will be between around the 1.5-2KG which isn't too bad. 

 

I'm having issues getting the PETG to print correctly on larger thigns so progress will no doubt slow right down and I doubt it will be ready by the end of summer so the first proper speed run will be in 2021. 

 

 

 

Edited June 23, 2020 by Alex97