Making a 3D Printed LMP1 Wheel

One of my first projects with my Ender 3 was perfectly timed with the middle of the LMP1 golden years of le Mans with Porsche winning the 2017 race with their 919 Hybrid. I figured if I’m going to all of the trouble of making my own wheel then I might as well make the best that year, so I did.
All of the files used in this was sourced from Thingiverse.

Original Files:

For this project I decided to print and make the following designs:
Porsche 919 Wheel by Leecarl,
LCS Mono Arm F1 Shifter by Leecarl,
Thrustmaster Hub Adapter by Slowly.

Printing:

One of the first parts I printed was the hub adapter as it seems like the make or break component of the wheel so why not start there and work my way towards the front?

Me testing out the printer after assembling it.

The hub fabrication went well for my first slice. I went for 0.15mm layer height as I thought the threads could probably do with being as smooth as possible and bumped up the infill to 50% for some added strength.

Next up was the shifters. After printing out the main hub I then inserted the nylon spacers in then attached the magnets and limit switches.

Ignore the rest of the wheel being already made

The last thing to print (initially) was the actual wheel itself. Printing went well overall and the design is very good, Leecarl’s instructions were very thorough although I decided against using rotary encoders and the screen as I accidentally melted all of the encoders and I normally play in VR.

The first part of the rim I printed was the grips. After printing I used a soldering iron to melt in place the threaded inserts

I practiced on a failed print, hence the support material still on the part

After all of the inserts were… inserted, it was time for the wiring and buttons.
For the buttons and rotary encoders I used what was recommended in the original files.

12 Knitter Switches, 9 Rotary Encoder and 2 Buttons in the Grips.

To be able to actually use these inputs I used SimHub and an Arduino Uno, setting up a matrix for all of the switches. I initially tried to use a protoboard to make a little rats nest to simplify the process but it ended up complicating things even more.

Instead I just daisy-chained all of the buttons together which was another rats nest but a slightly less confusing one.

After many hours on the soldering iron, melting a few button along the way, I finally finished it. And so, booted up Assetto Corsa to take this thing for a test drive.

There you can see my custom 7+R Gear Lever I made as well!

Unfortunately the test drive didn’t go so well as something, either the arduino or simhub, wasn’t really reliable and the lever arm shifter didn’t register gear changes most of the time.
I decided to replace the interesting but non-operational paddle shifter with proper normal ones and to replace the arduino with a universal joystick encoder similar to one of these:

The proper paddle shifters feel way more tactile and despite the rotary encoder not being compatible with the joystick encoder, they didn’t even work in the first place as I melted them all! A similar fate was discovered for the original buttons is that I seemed to have used a soldering temperature way too high and so have melted all of those buttons too. In the end I replaced the original buttons with pre-soldered ones from amazon and used a new jst crimping kit to plug them into the joystick board.

This is the sad final state of the wheel today as I kind of lost interest as it seemed that there is always something not always working 100% of the time and one more thing stopping me from using it. I decided to move onto designing my own gear lever as throughout the project I had found a love for some of the older cars in PC2 and had started to want a H pattern shifter, maybe another post for the future,

Thanks for reading!

These shifters are amazing and the few Nordschleife laps I got out of them were some of my favourite yet!

Making a Remote Control Spitfire

In 2018 I made a foamboard spitfire by Flite Test with my dad. The plane is made of laser cut foam board that is hot-glued together and was very easy to assemble; here’s how we did it and out experience flying it!

(This specific version of the kit is no longer sold but a newer version is available here.)

There’s 2 ways to make this plane: either download the plans (left) and source and cut the foamboard yourself or buy a laser cut kit (right) that also includes the electronics; we got the kit version.

The first step was to build the “power pod”, this removable pod holds the motor, battery, receiver and ESC. We then reinforced the front of the pod with fiberglass tape to prevent the motor ripping itself off of the plane.

Next was to make the wings:
The wings are designed really well and the process to assemble is well thought out. First you make the ailerons by cutting a 45° wedge out of the wing and the aileron to give it some clearance, you can see this a bit in the left picture. We then squirted a thin line of hot-glue along it and spread it into a thin film as the only thing holding the aileron on was just the paper of the foamboard.
Once the aileron was done we repeated the 45°cut for the leading edge of the wing and then scored some lines on top of the wing to make shaping easier.
We then glued in a servo and glued the top of the wing to the bottom.
After finishing the right wing we did the left then glued the two together.

After a few more hours of gluing foam, burning our hands and forgetting to take pictures the plane was completed. The most frustrating part of making the plane was fishing the servo wires through the fuselage but once that was done I tested the movement by using an Arduino Uno to test sweep the range of motion of each servo and control surface.

you can see the power pod i mentioned earlier

Finally the plane was completed, now the only thing to do was to charge the brick of lithium and fly it!
The very first flight lasted all of 5 seconds as I didn’t realise that ALL of the control surfaces were inverted; as expected the plane nosedived immediately and slammed into the ground, slightly snapping the leading edge of the left wing.
Fortunately the plane wasn’t damaged too much and we were able to fly it again after checking the controls. The plane flew really well and was very stable as the rudder had enough authority that you didn’t really need to bank to turn which, as a beginner flier was very helpful.
After flying for around 5-10 minutes I noticed the motor wasn’t giving as much power as it had so we assumed that battery was probably nearly flat so I landed it; the plane has no landing gear and for some reason my dad didn’t trust my flying enough to catch it for me so a belly landing it was (which the plane is designed for really). The belly landing went well although it broke the plastic propeller but that was fine as they’re quite cheap in bulk. The wing was easily fixed with hot glue as it is only foam board.

After getting home my mind was filled with things to add to this thing, eventually settling on making a “bomb” rack for it, pictured above.

All in all I think this is a very good design and is very good for it’s price, I would recommend this to anyone looking to join the hobby!
Thankyou for reading and I hope you enjoyed!

Making a custom guitar from a DIY kit

For the Christmas of 2017 I got a kit for a Stratocaster guitar and after the holidays I started assembling it. This project was quite a while ago so a few details might be a bit fuzzy.

Here’s the original kit looked in the picture below;
including everything you need to make an electric guitar:
-body (un-stained and un-varnished)
-neck (un-stained and un-varnished)
-faceplate
-rear cover
-bridge
-electronics (low quality pickups and strings)

this is a similar kit off of gear4music.com

After laying the body on the kitchen table I sanded the body a bit to remove the rough spots before prepping it to be stained:

The second step in this build was to paint/stain the body of the guitar to either the colour or wood texture that I want, I decided to stain the body and neck to what I believe was a dark mahogany shade. It took a few weeks but in the end of the staining phase, the body turned to a beautiful dark shade.

And after taping up the fretboard I started the neck!

After another few weeks of painting coats and sanding down I then sanded the varnish all the way up to wet-sanding with I think around 2000 grit paper.

I then lined up the faceplate I got to figure out where to place the bridge:

And then attached the bridge and screwed down the original faceplate for the first time:

After the excitement of being nearly finished I coated the pockets in the body with metal tape for EM shielding and prepared the pickups.

The pickups I chose were black “hot rail” pickups almost exactly like the ones below; I used two of the single’s at the neck and middle position and one of the double’s at the bridge position.

All in all, the final guitar looked like this!
I later added a new strap with a securing rubber washer since the previous strap was too short and too worn out making it fall off.
If I was going to do this project again though, I would use a varnish with less friction for the neck and make sure to put the plastic nut the right way round!

Thanks for reading!

ANSWERED?Engine Design Regarding Stroke/Conrod Ratio and Off-Set Crankshaft, Now with Wrist Pin Offset: Desmos Illustration.

Recently I went to a university open day where I spoke to the Technical Specialist for Motorsport. There I showed him my previous blog on this topic and my questions in it regarding offset crank’s use in real life. He then explained that most of the time offset crank isn’t used as it makes packaging of the engine harder; I guess it also requires redesigning/building of the block during prototyping. He also explained that there is sometimes a small offset at the wrist pin instead to slightly achieve the same effect. The final problem he mentioned about offsetting anything is that it causes uneven wear to the cylinder wall, which makes sense.

After getting home from the open day I created the graph below to see if offsetting the wrist pin does have the same effect as the crank offset in terms of connecting rod angle:

And as you can see, offsetting the piston has the same effect as offsetting the crankshaft! The problem that immediately came to thought is that this can increase frictional losses because the wristpin is no-longer in the centre of the piston, so the force from combustion (which is in the centre) is now creating a moment of torque around the wrist pin; causing the bottom right and top left sides of the piston to be pressed against the cylinder wall.

I tried to create a graph to show the torque mentioned above but had difficulty calculating the force from combustion:
While I think the force during compression seems pretty realistic (interpolating between 1*atmosphere and compression ratio*atmospheric pressure), the pressure during combustion has to be off. I’m certain the cylinder cannot have approximately 100GPa at the beginning of combustion, right? (my working out is below)
I used the formula PV = k modified to PV = E as the SI units multiply to form Joules and then found E using the chemical energy density of gasoline and an air fuel ratio of 14.7 to 1 (assuming volumetric efficiency of 100%). I think the inaccuracies are caused by not modelling the thermal losses of the cylinder, which normally takes away from the energy used from combustion.

After the confusing failure of the forces graph I decided to see what would happen if I decide to mix the wrist pin and crank shaft offsets together and therefore made this graph:

As expected, the normal reduction of connecting rod angle occurred but I’m still curious as to what forces are being put into the cylinder walls; maybe next time, potentially using an engine simulator to get a plot of the pressure vs crank angle!

Thanks for Reading!

Me

My name is Samuel Hayes and I am a huge motorsports engineering geek.

I was diagnosed with Chronic Fatigue Syndrome (CFS) in year 6 of Primary School, which led to the majority of my secondary school education to be taught virtually.
During this time through binge watching ‘Phineas and Ferb’ and ‘Scrapheap Challenge’ I found my love of designing/building things which eventually mixed with my fascination with race cars to create a passion for motorsports engineering.

Hobbies:

As for hobbies:

I currently own and have since fully upgraded a 3D printer (Creality Ender 3) and use it to design and build useful things and also addons for my sim-racing setup and fun stuff.

I am a big sim-racing fan and have my own VR setup that I have spent un-godly amounts of hours playing and building extras for my simulator, such as functional gear levers and replica steering wheels of real race cars to allow me to have a more immersive experience.
I have currently:
designed and made an 8+R gear lever out of cardboard for truck sims,
3D printed a 4+R gear lever replicating the jaguar e-type V12 Group 44 from Project Cars 2,
a replica steering wheel of the Porsche 919 LMP1 car
and has designed and not yet built a replica LMP3 wheel (Cosworth CFW).

I also sometimes play flight simulators such as DCS and VTOL VR (would highly recommend the latter if you have a VR headset) and have flown a real glider before down in Ashford.

Another interest I have had for a while is programming, I have several Arduino’s and programmed a Snooker counter with one using a few buttons and an LCD character display. I started learning the Unity engine last year and am currently (and slowly) developing a glider simulator that works in VR but the project was put on the back burner for exams.

Last year I Joined an archery club relatively local and now shoot every weekend I can. I received the White arrow badge a few months ago

Current Qualifications:

A-level Mathematics (achieved grade B summer 2023)
A-level Physics (predicted grade A summer 2024)
Access to Higher Education Diploma in Science (set to complete summer 2024)

My recovery has been going very well for the last few years and am certain that I can achieve the above listed qualifications.

Future Aspirations:

BEng in Motorsports or Automotive Engineering, maybe pursuing masters programme
Career in Motorsports Engineering, specialising in Hybrid Powertrain/System design
Potentially a PHD in Electric Motor Design and Control

I am looking forwards to a career in endurance motorsports, designing hybrid systems and potentially joining the team as pit-crew!

Engine Design Regarding Stroke/Conrod Ratio and Off-Set Crankshaft: Desmos Illustration

Recently I have been watching a few videos by Driving4Answers on different engine layouts and why they exist mostly based on primary and secondary reactive forces from the piston and connecting rod moving during normal operations. While binge-watching these videos of his I came across a video explaining the importance of the stroke/conrod length ratio and it’s impacts on the acceleration of the piston(s).

He explained that as the conrod is pulled to the side by the crankshaft it must decrease in overall height to maintain a constant length, therefore pulling the piston down quicker.

After watching the video a few times I decided to make a graphical representation of the effect of this ratio using the Desmos Graphing Calculator

First Iteration

The first iteration of this graph was pretty simplistic, it only showed the moving piston and crankshaft with a list of variables to change. When the stroke is much larger than the conrod you can kind-of tell that the piston stays at the bottom for longer but too much and it glitches out, needless to say I had to go further:

Second Iteration

To make it easier to see the changes in the acceleration from using different ratios I created a second graph that also plots the position, velocity, acceleration, jerk and snap of the piston and also the angle of the connecting rod for some reason.

Experimenting with Iteration 2

Using iteration 2 I was able to easily compare different ratios to see their effect on: how even the position, velocity and acceleration of the piston is.

Conrod Length = Stroke:

When the conrod is the same size as the stroke the piston seems to stay at the bottom for longer than it does the top.

Conrod Length > Stroke:

When the conrod is longer than the stroke (50% this case) the piston seems to spend more of an equal amount of time at either end of the stroke.

Conrod Length < Stroke:

When the conrod is smaller than the stroke (50% this case) the piston is at a stand-still for most of the rotation until the crankshaft is above axis of it’s rotation. I would say that this mechanism with these dimensions would be impossible in real life.

Conrod Length approx infinity:

Although the length technically becomes undefined, the acceleration and velocity (and presumably position) become perfectly sinusoidal as the conrod is infinitely more times larger than the stroke radius.

Crankshaft Off-Set

With the second graph I found it much easier to spot the effect and so I left the idea alone for a while until I saw another one of d4a’s videos.
In this new video he showed the effect of off-setting the crankshaft from the cylinders to reduce the maximum angle of the connecting rod during the power stroke to reduce frictional losses.

First Iteration

I decided that this was also interesting and therefore decided to re-make my second graph into one that could also move the cylinders laterally.
In the first iteration of the off-set-able graph I simply altered the second graph by adding an off-set in certain places. Through experimentation I found that setting the off-set to a quarter of the stroke reduces the maximum and average angle of the connecting rod during the power-stroke, I later set this as the default value for the off-set.

Second Iteration

After a while of fiddling with my new graph I thought it would be cool to be able to see multiple pistons at the same time and potentially have them angled. The way I was illustrating the piston was that I was creating a table of points and telling Desmos to draw lines between them; unfortunately Desmos won’t let you input a table into another so I couldn’t just make a table of values for each piston and have another table render each one so I had to make my own way to draw lines between points.

This was just a simple function to take in 2 sets of coordinates and create a line between them.

But to allow for cylinder angle I had to add an angle to the drawLine otherwise I’d have to constantly work out a new angled point.

It took a lot of thinking and evil math but I got it working.

And so finally I created the graph to allow for cylinder angle and multiple pistons, I also added cylinder walls too!

I decided to make the default values that of the Harley Davidson Milwaukee 8 Big Twin.

My Question:

My one question about off-setting the crankshaft is are there any engine manufacturers actually doing this in their engines as I haven’t found an example of one yet?

Thanks for reading!

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