Fastest RC Jet Car (Runway Testing)

This is part 3 of this mini series.

Special thanks as well to the following for their help and advice during this series:

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DISCLAIMER: This video is purely for entertainment value. Personal use of video content is at your own risk. Recreations of experiments, activities and projects are the sole legal responsibility of the person(s) involved in replicating them. I can not be liable for any information or misinformation, wrongful use, damage to personal property, death or any circumstances that result from replication of any projects seen. Be safe!

[MikeStallone]

Happy to help man! Really appreciate the shoutout. 🔥 This is such a cool project and I can’t wait to see where this goes! My unique build also went through some growing pains but every time out was a learning opportunity and now we’re at 185MPH! Keep going and always happy to help 🏎

[KevinTalbotTV]

wooo! I made it into the vid!! thanks for the mention! was a pleasure to meet you. a few of us were using gyros, we have the futaba one. if it wobbles you can turn down the gain, but it looks like it might be picking up vibrations. i find the 3m double sided grey vba tape the best. cheers!

[tomatwalden]

That gyro would have been massively freaked out by the vibration. On RC helis, the gyros (flybarless units) are installed on an anti-vibration pad to help alleviate the effects, but the vibrations from rotary flight look like nothing compared the vibes you would get from running on rough tarmac. Looking at that, I'm not surprised the other guys didn't use gyros.

[mozkitolife]

The fact no one else was using a turbine shows how interesting and unique it is. Don't let this series die. Keep it up!

[NicholasRehm]

RC car speedrun community seems like a fun bunch… thanks for putting them in the spotlight!!

You’re probably right about the slop in steering causing your oscillations. Might be worth adding some stabilized rudder surfaces and leave the main steering unstabilized

[dan]

I LOVE how you always showcase your “mistakes, ” and reframe them as learning experiences; especially with your infectious positive attitude about how much you’ve learned. This is such a great example to show my young niece and nephew; well actually for anyone for that matter! Thanks for sharing this fascinating video with us!!!

[yobosses]

The issue with the gyro is that the steering sensitivity increases with speed. Meaning at low speeds the gyro gain is correct but at higher speeds the total output gain (steering + gyro gain) has increased causing the oscillations. I would not recommend a simple gyro for this. Maybe a flight controller with GPS to dynamically change the gain correctly for the speed?

[brucebaxter]

Gyro in a car will reach an oscillation speed due to the servo max slew speed.

You can reduce the problem by mounting the gyro on the upright so it turns with servo (or doesn’t turn with the car in a slide.

What you need to do is use a flight controller like ardurover to have gps pid position control for the whole length of the runway and onboard data logging.

[teaddict-]

My first thought was the servo. For those kind of speeds you probably want something heavy duty and pretty rigid, that may be part of what caused the gyro to get confused.

[galaxyowl]

One of the best series yet!

Edit:
I would love to see a mini Bloodhound build with the jet engine, as this would be realistic to the actual Bloodhound. (Because you mentioned redesigning the chassis to incorporate the engine)

[zloki]

Failed in creating a 100mph car but succeeded in gaining valuable information on how to get to a 100mph car SAFELY and RELIABLY. Not to mention tips and contacts from the event who have the same pursuit. That's a win for any engineer and glad you think the same way!

[greggv]

Just rebuild the steering with all metal, high precision parts so it has no slop. Put rudders on the fins and have the gyros operate those instead of the steering. Experiment with speed dependent actuation %. The faster it goes, the less correction to prevent applying so much steering input it makes the car turn too much. Another thing to look into is detecting oscillation caused by the gyro. In that case it should return the rudders to neutral and hold them until wobble stops. If two rudder servos are used, they could be both turned to maximum outwards to act as air brakes.

One more thing, mount the engine with a little bit of upward tilt at the rear to push the rear end down. Having it parallel to the chassis is going to make it rock forward, putting more force on the front wheels. That will put more drag on the front, less on the rear, leading to amplifying the effects of steering and wanting to spin around - resisted only by the big fins.

[JerryCrow]

I'd invest more into the suspension. An inwards toe angle makes the car want to go in a straight line, where an outwards toe angle makes the steering more responsible but the whole car way more unstable. Positive caster also helps with stability. Camber can be used to reduce the patch area.

[jorenvangoethem]

perhaps some kind of steering damper. it's something motorcycles also use at high speed to prevent a "death wobble" (kinda what your car is doing)

[adilsongoliveira]

Two suggestions: ditch the spektrum radio and go for something more modern like Crossfire or ELRS. If you want to use some active stabilization, go for something that provides you with logs so you can analyze the behavior dynamically.

[kylefrank]

Damn man, I'm 36 years old and have had an engineering mindset my entire life despite not going to school for it. To see someone your age making a jet powered RC car, then crashing, and having such a positive attitude about it, fills me with a lot of confidence about future generations. Keep developing your passion, by the time your my age your GOING to engineer something truly epic, and I can't wait to see it. Subscribed!

[gonuhi]

imagine if projectair, raz shifrin and kevin talbot do a collab

[rmg_lb]

Great video as always. I really like you reflecting on changes, looking for errors and being able to find them, even when they're your own.
When going on with this project, I would strongly suggest looking into landspeed record cars and their setup. All of them are low-drag, low-downforce configurations.
Especially with no wheels being driven, a rear wing makes not much sense for downforce, however the vertical stabilizer is often used in LSR cars.
The rear wing will effectively lever up your front wheels, making the car instable at speed. A front wing to counter this or even a unified "central" wing (think aircraft aerofoil upside down) might make sense, with a small vertical stabilizer at the rear.

As I said, enjoy your content and the experimenting you are doing. Have fun!

[toolbgtools]

gyro's are programed to work at acceleration around g (10 m/s), it gives different outputs at higher accelerations. you can use accelerometer for correcting gyro's output.

[ChristianGregersJørgensen]

This is truly how educational content should be presented - highly valuable and greatly enjayable.