Not logged in [Login ]
 Sciencemadness Discussion Board » Fundamentals » Miscellaneous » Jet Bike Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues   » Test Forum

Author: Subject: Jet Bike
ecos
National Hazard

Posts: 464
Registered: 6-3-2014
Member Is Offline

Mood: Learning !

Jet Bike

Hi All,

I saw a youtube video for a Russian guy who use a small jet engine to drive his bicycle. It sound really crazy but it was very cool idea.
I saw before people adding a small motor to the bicycle but this need a lot of modification to the bicycle( not a simple thing).

I searched internet but it seems a small jet engine with good thrust costs a lot :/ (from $2000 to$3000). I was thinking to make the engine but I couldn't find much information ( step by step) on how to make a reliable one. do any one have some resources here?

I was also thinking about the control circuit for the engine. I think i need :
1- temperature sensor to avoid overheating
2- fuel pump control to control the speed

did anyone try something like this before?
Bert
21-2-2018 at 05:40
barbs09
Hazard to Others

Posts: 102
Registered: 22-1-2009
Location: Australia
Member Is Offline

Mood: No Mood

You'd need to be a pretty good machinist of reasonably exotic materials to make a jet engine I would have thought. A rocket bike however....

Ill look out for you on the Darwin Awards
LearnedAmateur
International Hazard

Posts: 513
Registered: 30-3-2017
Location: Somewhere in the UK
Member Is Offline

It would be a small turbine from a model aircraft and they are very loud, I used to fly model aircraft at a specialised field and a few members owned them, fun to watch and very expensive (AUD\$3000-5000 for the lower end builds). If you live in an urban area then I would advise against this idea, an electric motor or a small two-stroke may be more practical and easier to configure. If you need some information, it may be an idea to poke around some RC forums since it’ll be pretty much the same setup, just that you’ve got wired connections instead, but I doubt it’s something you could make yourself.

[Edited on 21-2-2018 by LearnedAmateur]

In chemistry, sometimes the solution is the problem.

It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
SWIM
International Hazard

Posts: 729
Registered: 3-9-2017
Location: 26 Ancho street
Member Is Offline

Mood: teratogenic, but now 90% bone marrow free!

Turbojets built at home are an awfully tall order.

Getting decent thrust is harder than you'd think from the simplicity of the principles.

And without those expensive materials mentioned above, they don't last very long.

However there are always pulsejets. They're cheaper and simpler, so the fact they burn out if made from cheap materials matters less. I think there were some manufactured for model aircraft back before miniature turbojets were practical.

Motorjets are simpler than turbojets too, but I doubt the claims that you can get useful thrust without a decent compression ratio: I don't think spraying gas into a fast moving air stream like from a leaf blower motor would give you much of a kick.

Motorjets that have high speed axial compressors, and positive displacement blowers, have been used in a few aircraft successfully. Maybe some Soviet fighters from the 40s, and that Caproni prototype from before the war.

One other thing: If you get this running be sure to check your local regulations.

Many places have laws against use of rocket or jet powered vehicles on public roads.

I'm getting a Covid vaccine shot today.

Kind of a waste as I'm having my immune system erased in a couple of months and will need another one.
And a DPT, and an MMR, and etc.

Pity I can't get my smallpox renewed, but those are hard to get these days. Maybe they'll give me cowpox if I ask real nice.
Do they still do polio?

ecos
National Hazard

Posts: 464
Registered: 6-3-2014
Member Is Offline

Mood: Learning !

Many thanks for the replies.

I found this book: Home Built Model Turbines

I will get this book and have a look. it seems interesting !

@SWM, you are correct, I need to check regarding local regulations.

Σldritch
Hazard to Others

Posts: 241
Registered: 22-3-2016
Member Is Offline

Mood: No Mood

This is an interesting read: http://www.pulse-jets.com/valveless/
Twospoons
International Hazard

Posts: 1124
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline

Mood: A trace of hope...

The other way is to build a turbine based on a used truck exhaust turbo - plenty of internet resources for that. You only have to build the combustor, as all the spinny, high speed stuff, bearings and housings comes with the truck turbo.
Instead of just directing a jet of hot gas out the back (which is a rather inefficient way to create thrust), an alternative is to have a third turbine connected to the bicycle wheel and use that to extract power from the exhaust gas. I can't recall the exact term for this, but it works in a vaguely similar fashion to a torque converter.

Pulsejets ... say goodbye to your eardrums!

Helicopter: "helico" -> spiral, "pter" -> with wings
Corrosive Joeseph
International Hazard

Posts: 898
Registered: 17-5-2015
Location: The Other Place
Member Is Offline

Mood: Cyclic

 Quote: Originally posted by ecos I will get this book and have a look. it seems interesting !

Here is your book - "Home Built Model Turbines "

Attached

/CJ

Attachment: Home Built Model Turbines.djvu (4.2MB)
This file has been downloaded 169 times

Being well adjusted to a sick society is no measure of one's mental health
Twospoons
International Hazard

Posts: 1124
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline

Mood: A trace of hope...

"Turboshaft". Thats the term I was looking for.

Helicopter: "helico" -> spiral, "pter" -> with wings
ecos
National Hazard

Posts: 464
Registered: 6-3-2014
Member Is Offline

Mood: Learning !

My dreams are over
those engines require a lot of effort and skills!
NOT EASY :'(

@Twospoons, I think Turboshaft engine is for devices that require high RPM but doesn't deliver enough torque.

sounds like I will give up.

I will try to build electric bike using electric motor. it will be much easier than those engines!
ecos
National Hazard

Posts: 464
Registered: 6-3-2014
Member Is Offline

Mood: Learning !

I had a look on the basic design of diesel and petrol engines.

I see the process as : inject air , compress air, inject fuel , ignition, release exhaust.

I think it is the same process of the jet engine. I don't see much difference ! any comments?

I would imagine the difference maybe because jet engines has high compression ratio but if this is true, why don't they use the same concept in cars !
Bert

Posts: 2730
Registered: 12-3-2004
Member Is Offline

Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".

Power choice for aero use and ground/water use are governed by weight as well as efficiency, maintenance and other costs. You will find tons of gas turbines in aero applications, light weight per output and reduction of reciprocating parts and the associated wear/extending engine maintenance intervals related to such wear are big factors in this choice.

The only major use of gas turbines for a production land vehicle I know of right off hand is the prime mover of the M1 Abrams MBT.

[Edited on 22-2-2018 by Bert]
SWIM
International Hazard

Posts: 729
Registered: 3-9-2017
Location: 26 Ancho street
Member Is Offline

Mood: teratogenic, but now 90% bone marrow free!

FIAT, Rover, Chrysler and some others worked at turbine car design during the post WWII period.

Prototypes were built and tested, and Chrysler even ran off a few dozen cars for extended consumer testing trials back in the 60s.

But no dice. They just weren't practical then, and nobody has really pushed for them since.

I suppose a comeback may be possible though. One thing that made turbines tough to engineer for the road was the highly variable loading. That problem goes away if you mount the turbine in something like a Chevy Volt where it can just run steady-state and produce electricity. Save a bit on reduction gearing too.

I'm getting a Covid vaccine shot today.

Kind of a waste as I'm having my immune system erased in a couple of months and will need another one.
And a DPT, and an MMR, and etc.

Pity I can't get my smallpox renewed, but those are hard to get these days. Maybe they'll give me cowpox if I ask real nice.
Do they still do polio?

Twospoons
International Hazard

Posts: 1124
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline

Mood: A trace of hope...

 Quote: Originally posted by ecos I had a look on the basic design of diesel and petrol engines. .... I think it is the same process of the jet engine. I don't see much difference ! any comments?

Looks up the differences between the Diesel cycle, Otto cycle and Brayton cycle, especially the pressure / volume and enthalpy / entropy diagrams.

Notable differences are jet compression is 'constant volume' , and jet combustion is "constant pressure".

All are approximations to the Carnot cycle, which is supposed to be the ideal heat engine cycle for efficiency.

Helicopter: "helico" -> spiral, "pter" -> with wings

 Sciencemadness Discussion Board » Fundamentals » Miscellaneous » Jet Bike Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues   » Test Forum