Jet Questions 66

Order may not exactly match your list:
1) Modified turbofans for industry?
2) Jet dragsters... ... again...
3) Test cell bellmouth... ... again...
4) Power tools?
5) combustion air & cooling air

[gator]

I am a life long aviation enthusiast and I am starting to learn and study modern jet engines. I am fascinated by the quality and clarity of you Q and A videos. Just want to say thank you for the insight and understanding you provide.

[latovaas]

A few weeks ago I was working on the 475th Fighter Group exhibit at the Planes of Fame Museum In Chino, Ca.  There was a crew working on the P-38 Lightning getting it ready for an upcoming air show.  If was fascinating seeing this aircraft with all it covers and inspection plates removed.  Not a power tool in sight.  Everything was done with hand tools.  When you work with hand tools you can feel when something is not right.  Then stop, correct the problem before continuing.   If you strip the screw it’s not so bad.  However when you strip the threads on the female side it going to take hours to fix.

[clydecessna]

There are privately owned after burning jets in the US, Some guy has a F-100 ; Also there is a Mig 21. In the UK we have a Sea Vixen floating around, In South Africa there is a Lightening doing its stuff.

[robertson]

Thanks! I wish I knew why these fascinate me so much - you do a great job explaining a technology that I never knew anything about. Keep 'em coming!

[ksbs]

Agent JayZ, love your videos. You clearly love what you do. Every time I watch one I learn something. The most fun is when I realize I completely misunderstood some part of the machine and you teach me how it really works

[MoTheG]

I once experimented with inlet cones and found the difference so significant that it was clearly measurable with household equipment. The air hates sharp edges, it rather takes a detour.

[austinclark]

At 21:00 you talk about fastener costs. When i worked for Alcoa, I made aerospace fasteners and I was extremely surprised at the cost of some parts.We made this one tiny, tiny nut, possibly 2mm in diameter, that I could easily fit 60, 000 USD worth in my pants pocket. If only there was a black market for the parts. lol

[merlyn]

One solution to cockpit air conditioning, although an old one and still in use by aircraft such as the CL-41 Tutor flown by the Snowbirds (Orenda variant of the J-85 engine.) use an expansion turbine driven by compressor bleed air (I think 8th. stage.) This hot compressor air is routed through the expansion turbine where it is decompressed and cooled to frigid temps. A second pipe with full hot bleed air runs alongside the expansion turbine and just downstream of the expansion turbine, a modulating valve receives both the hot and cold air and mixes the hot and cold air at a ratio selected by the pilot for personal comfort. Good system. You can make it snow (literally) in the cockpit or make it hot enough to roast your butt.

[davidkatz]

Thanks for another great lesson. Some time in the future we should all be familiar with most of the systems of the turbojet engine from the inlet guide vanes to the afterburner and how these differ from gas generators and power turbines. When is the final exam?

[johnnypea]

I watched a bunch of your videos and now sneak into the airport maintenance hangers and work on airliners.

[northernwatcher]

thanks for the question answer about powertools. I know I had a question some time ago about how to avoid equipment damage by doing things carefully, as I have surely stripped my fair share of screws, etc. great answer.

[SuperSecretSquirell]

know that I was all about having a Ti fan blade to display in my living room, but I think I need that cutaway model in the living room now lol

[DScottDuncan]

Thanks for informing me regarding the jet cars! I never new that was why they 'bang' their way to the line! I thought it was for show. Take care.

DD

[JetEnginesIndia]

Hi AgentJayz, i love watching your videos.
very informative they are.
I have a question:-
what is the difference between the shape and functioning of a fan blade(as in case of fan of a turbofan engine) and the compressor blade.
Are both the aerofoils or a the compressor blades are shaped so as to produce more pressure ratio per stage.??

Thank you.

[Diehard]

Hi Jay,
Thanks for all the awesome videos. You do a good job of explaining things.

What are the pros and cons of a free power turbine?

I'm having trouble finding much useful information on this. I have googled it and watched all the videos in your power turbine section. I'm sure you would have talked about this before, but I am having trouble finding anything about it even after watching literally hours of your videos. Hahahaha! Apologies if you have answered it before.

Would I be correct in saying that it allows everything to be at its optimum rpm at the expense of slightly reduced efficiency. As I assume a direct connection would be more efficient.

Keep up the good work.

[SnowRaptor]

Thank you for your videos, +AgentJayZ!

In a stationary engine without a bell shape, the "sharp corner" that the air must follow also generates a lot of turbulence, right? Those vortices we see sometimes in fornt of stationary aircrafit illustrate this pretty well, don'they?

[bhueske]

Hey Jay,
hello from Germany and thanks for your great Videos.
In this Video, you showed us the cutaway of a J79 and the first stage turbine nozzles. Did i see right and the first stage of turbine nozzles is welded into this ring? If one nozzle is worn do you have to change the complete ring of nozzles? seems quite expensive.

[jim]

Hi Jay,
Have you ever heard of the  J-93 engine?
 I think it was a scaled up J-79

[sethjensen]

In reference to the LM 2500 as it relates to its turbofan counterpart, is there any horse power loss when the engine does not have the fan on it? As I watch these videos I think I understand that the fan is merely to produce an enormous amount of thrust and that's about it. When you don't need thrust you don't need a fan. But the fan helps take in air which might help with power but on the flip side it takes power to run the fan via a power turbine which might be about a wash when it comes to total power output. So is there any output horsepower change by adding or removing a fan?

Also thank you for responding to some of my questions. It makes learning about this stuff a lot of fun.

[PeterSCampbell]

Ha, Thanks for getting back to me! You did answer my question...It's all in the wording isn't it? Anyways,  Keep the videos coming and keep stimulating my mind.