All US 4th gen fighters (F14, 15, 16, and 18) run afterburning turbofans. It's true that they're bulkier than turbojets, but in jet fighters, they tend to run a pretty low bypass ratio which minimizes the extra bulk.Arjun Singh said:You just differentiated high bypass and low bypass jet engines right? If I am not mistaken 4th generation fighters are all working on turbojets. Is turbofan the 5th generation upgrade? Also turbofans are bulkier than turbojets ain't they?
The Wiki article sort of confirms how I remembered it. There is a massive difference between (most if no all) jet engines and rockets. A lot of the the thrust that's delivered comes from a 'fan' which makes it very little different from a propellor. A gas turbine can drive another mechanism (copter rotor or alternator) but that isn't relevant to this thread (I think).russ_watters said:Probably, but either way I consider that semantics. A turbo fan "just moves air" even if some is bypassed around the jet part. Does that make it similar to a turboprop or turbo shaft on a helicopter? Perhaps. Yes, the line between types of engines and naming conventions can be blurry.
cjl said:There's no real legal limit, other than that it becomes increasingly difficult to meet any kind of emissions standards and reliability. That having been said, I bet you're thinking of the (claimed) 5000 horsepower Devel Sixteen. I'll be surprised if it ever actually happens though...
Cool Helicopter.cosmik debris said:Tyres would be expensive. I've heard of US$20000 for tyres of some of the Supercars.
Cheers
cosmik debris said:Tyres would be expensive. I've heard of US$20000 for tyres of some of the Supercars.
Cheers
What makes a good tyre apart from the quality of rubber polymer used? I am a novice in this category and though this thread is for the discussion about aviation technology yet automobiles are quite similar.cjl said:Yeah, though there's really no reason why tires should be anything close to that. Pretty much any of the supercars should work fine on something like Michelin Cup2 or Pilot Sport 4S tires, which (in supercar-ish sizes) tend to run around $400-600 per tire.
So overall two primary components of tyre as a product. Material and Tread pattern, which as you say is specific to application. What I understand is, wet weather tyre would have different tread pattern from a hot weather tyre. Or a standard tarmac tyre would have different tread pattern from offroading type. Same between ones for high speed cars and regular cars. Also, vehicles with different center of gravity or weight or application will use tyres with different tread patterns. I am assuming that tyre material in all the mentioned categories can remain the same or with minor differences, right? And how do they differ in shape as all tyres are round and visible differ only in thickness?cjl said:There are a number of factors - the rubber compounds, the internal construction of the tire (materials used to reinforce both the sidewall and the tread area), the overall shape of the tire, the tread pattern that is cut into it, etc. There's also not one "best" design - it's heavily application specific.
cjl said:Yeah, though there's really no reason why tires should be anything close to that. Pretty much any of the supercars should work fine on something like Michelin Cup2 or Pilot Sport 4S tires, which (in supercar-ish sizes) tend to run around $400-600 per tire.
cosmik debris said:I agree, but in some countries, mine included, insurence and various certificates of fitness require the tyres to be speed rated at the top speed of the car regardless of whether you would actually drive that fast.
Cheers
Arjun Singh said:So overall two primary components of tyre as a product. Material and Tread pattern, which as you say is specific to application. What I understand is, wet weather tyre would have different tread pattern from a hot weather tyre. Or a standard tarmac tyre would have different tread pattern from offroading type. Same between ones for high speed cars and regular cars. Also, vehicles with different center of gravity or weight or application will use tyres with different tread patterns. I am assuming that tyre material in all the mentioned categories can remain the same or with minor differences, right? And how do they differ in shape as all tyres are round and visible differ only in thickness?
cjl said:Both the Cup2 and the 4S have the highest speed rating in existence - (Y), which means in excess of 186mph.
What about tyre refurbishing? How effective is it to recycle an old tyre and make it workable again? There is already a good market for refurbished high end tyres sold in cheaper second hand markets.cjl said:True, but there's no specific rating above 186, so from a legal perspective, there really isn't a way to distinguish the tires required for a Veyron from those required for a Corvette. If you wanted to spend any significant amount of time over 200mph, you'd probably just want to contact the tire manufacturer in those cases, since there isn't actually a rating for it.
Not that rare to say. Perhaps not a common trade yet it exists moderately available. See, these layers to product trade increases aspirational value for the expensive products. Someone using a refurbished high end tyre is more likely to buy it new someday as compared to someone who regularly buys moderately expensive tyre and is not aware of the performance upgrade such a tyre can give to his or her vehicle. Just a thought! Works well for many value intensive product categories.cjl said:I have never heard of refurbishing tires for high performance sports car use, and even for cheaper cars, I believe it's very rare. It's very common in the US for heavy commercial use on trucks and buses though.
Arjun Singh said:Cool Helicopter.
Arjun Singh said:Hey any comments about this new copter? Considering that coastal cities, with over water air space can accommodate a good number of air taxis and privately owned copters. Does anyone thinks that role of turboshaft engine makers in that scenario would become more prolific in terms of price, transmission innovation, variable fuel compatibility, design and overall performance? Also, would that make the modern copters become completely safe as a common form of inland urban transportation? Want to understand community's views.
Do you mean Turbojets getting replaced by Turbofans? There has been some comments about this in the thread. As I have understood, apparently due to their enhanced fuel efficiency turbofans or high bypass jet engines are slowly getting preference over turbojets. Still due to the size and power plant design they have very specific applications. Keep contributing. Cheers!sophiecentaur said:Are there any straight jet engines used these days? I thought they were more like Fan engines these days
- quieter and at least as efficient.
What about wheeled construction machines?A.T. said:Among road legal sports cars this one has a lot HP:
https://de.wikipedia.org/wiki/Bugatti_Chiron
I don't know about other types of vehicles though.
Can a similar design be made applicable to high speed ships? I believe majority naval fleets (commercial or defence) currently run on diesel or SHS piston engines driving a propeller. Viscosity and fluid mechanics may differ from air yet the propulsion theory is the same. What do you think?russ_watters said:Probably, but either way I consider that semantics. A turbo fan "just moves air" even if some is bypassed around the jet part. Does that make it similar to a turboprop or turbo shaft on a helicopter? Perhaps. Yes, the line between types of engines and naming conventions can be blurry.
What about googling it yourself?Arjun Singh said:What about wheeled construction machines?
In particle physics, when two sub atomic particles interact, is gravity involved in it given their quantum weight which I am sure has a specific value? Also do their post interaction trajectories affected by gravity? Let's assume that the electromagnetic force of the respective atom is balanced in the interaction.David Lewis said:I assume you're talking about the power or thrust maximum ratings. Since the engine supplier doesn't know which propeller is going to be used, or other relevant variables, it's simpler in the case of propeller-driven aircraft to specify maximum rated power. The designer multiplies power by estimated propulsive efficiency to arrive at thrust available.
In addition to the max ratings there is also thrust and power output under operating conditions, which varies with throttle setting, airspeed, and other factors. Aircraft engine horsepower is not directly comparable with automobile engines. Cars use a different measurement protocol.
True with jet engines. Piston engines and direct drive electric motors are often designed to provide lots of torque at low speed. A slow-turning propeller can produce thrust more efficiently.
Confusingly, engineers often say mass when they mean weight. If a body is said to "weigh" 10 kg, it is understood colloquially to mean the amount of gravitational force the body would experience near the Earth's surface.
Thanks for your advice. Idea is to know the opinion on topics to share understandings. Contributory extent of members here is based on free will.A.T. said:What about googling it yourself?
Unless it's massless, each quantum object does have its own gravitational field but it is too weak in most cases to have any significant effect by itself. You are dealing with strong and electro-weak interactions when it comes to protons, neutrons, quarks, hadrons, etc.Arjun Singh said:…when two sub-atomic particles interact, is gravity involved in it given their quantum weight which I am sure has a specific value? Also do their post-interaction trajectories affected by gravity? Let's assume that the electromagnetic force of the respective atom is balanced in the interaction.
Didn't understand the strong and electro-weak interactions. Do you mean the chemical or ionic reactivity involved in their interaction or is it something to do with their valance relativity? I mean their atomic number relativity or position in the atom? I am not a trained physicist so pardon the crude terminology.David Lewis said:Unless it's massless, each quantum object does have its own gravitational field but it is too weak in most cases to have any significant effect by itself. You are dealing with strong and electro-weak interactions when it comes to protons, neutrons, quarks, hadrons, etc.
To conclude, any sub atomic or molecular interaction is a product of all these forces working as per their quantum relativity to the interactive premises of the reaction. Depending upon the nature of the reaction the designated force leads the process. Is this a closest to correct statement?David Lewis said:The four fundamental forces are:
Strong interaction, or strong nuclear force (nuclear fusion)
Weak interaction (nuclear fission)
Gravity
Electromagnetism (chemistry)
I've put in parentheses the corresponding phenomena to which the four forces informally relate.
Broadening the context, I have been conceptualizing a clean plastic to fuel process through plasma conversion. If I am not mistaken, at absolute plasma state all materials become identical and can be utilized for mechanical work without any harmful fallout. My question is, once the plasma precipitates can the material be recovered back to some reusable polymer state minus the used mass as heat loss and is it possible for the entire material to be utilized without any residue?David Lewis said:Of course. As you pointed out, depending on the branch of science, you may be focusing on one interaction at a time though. In everyday chemical reactions you will not be concerned about strong or weak nuclear forces directly as you would be in designing an atomic reactor. And in celestial mechanics, you will primarily deal with gravitation, and so on.
This appears to be word salad. Possibly you envision heating up a material to the point where its atomic nuclei and their component protons and neutrons spontaneously disassociate into a "plasma" of quarks. We cannot heat a meaningful quantity of material to such a temperature, cannot confine the resulting plasma, cannot use such a process to perform useful work and cannot cause any particular material to "precipitate out". The idea of the residue being reusable is not sensible since the energy inputs to the process would be huge and almost certainly unrecoverable.Arjun Singh said:Broadening the context, I have been conceptualizing a clean plastic to fuel process through plasma conversion. If I am not mistaken, at absolute plasma state all materials become identical and can be utilized for mechanical work without any harmful fallout. My question is, once the plasma precipitates can the material be recovered back to some reusable polymer state minus the used mass as heat loss and is it possible for the entire material to be utilized without any residue?