PDE engine video

Moderator: Mike Everman

Dave
Posts: 226
Joined: Sat Nov 08, 2003 7:03 pm
Antipspambot question: 0
Location: Buffalo, NY

re: PDE engine video

Post by Dave » Fri Jul 15, 2005 11:35 am

This statement will prove just how little I know about PDEs, but, I find it interesting that they induce a plug of cold air, to isolate the next charge of fuel and air from the one just fired. ( http://www.innssi.com/pde01.htm ) This could also be accomplished in a Pulse Jet with a second smaller and shorter (again air only) intake. What would be the benefits and / or drawbacks of doing so?
Dave

Al Belli
Posts: 557
Joined: Thu Oct 09, 2003 10:36 pm
Antipspambot question: 0
Location: Pennsylvania - USA

re: PDE engine video

Post by Al Belli » Sat Jul 16, 2005 12:20 am

Hi Dave,

Check this patent for added intake effect.

Al Belli
Attachments
pat.png
(5.65 KiB) Downloaded 852 times

Mark
Posts: 10743
Joined: Sat Oct 11, 2003 10:14 pm

Re: re: PDE engine video

Post by Mark » Sat Jul 16, 2005 12:23 am

Dave wrote:This statement will prove just how little I know about PDEs, but, I find it interesting that they induce a plug of cold air, to isolate the next charge of fuel and air from the one just fired. ( http://www.innssi.com/pde01.htm ) This could also be accomplished in a Pulse Jet with a second smaller and shorter (again air only) intake. What would be the benefits and / or drawbacks of doing so?
Dave
I wonder what kind of apparatus they are using to drive the valves? The site promoters said they found there was enough energy to use some of the gases to drive the valves, but I don't see that in action.
Mark
Presentation is Everything

dynajetjerry
Posts: 465
Joined: Thu Jan 27, 2005 4:57 pm
Antipspambot question: 0
Location: Ohio, USA

re: PDE engine video

Post by dynajetjerry » Sat Jul 16, 2005 3:07 pm

Guys,

Concerning the PDE at Wright Field mounted on a Rutan Long-Eze, I asked Dr. Schauer several questions when it was publicly demonstrated.
In answer, he reminded us that this was a very early and immature concept that used many off-the-shelf automobile components, where weights were not important factors. As a result, static thrust was 150 lbs. when operating properly but at the Field, it was 100 lbs. Gross weight of the "bare" engine and peripherals was 800 lbs.!

I'll agree that it is a proof-of-concept device rather than one that has any probability of being useful, as is.

Jerry

skyfrog
Posts: 539
Joined: Fri Jul 23, 2004 11:39 am
Antipspambot question: 0
Location: Kaohsiung, Taiwan
Contact:

Re: re: PDE engine video

Post by skyfrog » Sat Jul 16, 2005 3:23 pm

dynajetjerry wrote:Guys,

Concerning the PDE at Wright Field mounted on a Rutan Long-Eze, I asked Dr. Schauer several questions when it was publicly demonstrated.
In answer, he reminded us that this was a very early and immature concept that used many off-the-shelf automobile components, where weights were not important factors. As a result, static thrust was 150 lbs. when operating properly but at the Field, it was 100 lbs. Gross weight of the "bare" engine and peripherals was 800 lbs.!

I'll agree that it is a proof-of-concept device rather than one that has any probability of being useful, as is.

Jerry
Thanks, that explained everything. No wonder the airplane powered by this PDE could perform taxiing only. Sounds like PDE is still very promising, if those automobile components could be replaced with some light weight components.
Long live jet engine !
Horace
Jetbeetle

Bruno Ogorelec
Posts: 3542
Joined: Sat Oct 04, 2003 7:31 am
Antipspambot question: 0
Location: Zagreb, Croatia

re: PDE engine video

Post by Bruno Ogorelec » Sat Jul 16, 2005 7:30 pm

From what I can see in open sources, most designers seem to be shooting for a kind of a high bypass turbo-PDE. You have a turbojet core providing a great amount of airflow and thrust for low speed low-level flight, takeoffs and landings. Mounted in a concentric duct around the core are PDE tubes, which use turbojet's air pressure for aspiration and provide thrust for high-level cruise flight. Not a very elegant concept, but it might work.

skyfrog
Posts: 539
Joined: Fri Jul 23, 2004 11:39 am
Antipspambot question: 0
Location: Kaohsiung, Taiwan
Contact:

Re: re: PDE engine video

Post by skyfrog » Sun Jul 17, 2005 1:42 pm

Bruno Ogorelec wrote:From what I can see in open sources, most designers seem to be shooting for a kind of a high bypass turbo-PDE. You have a turbojet core providing a great amount of airflow and thrust for low speed low-level flight, takeoffs and landings. Mounted in a concentric duct around the core are PDE tubes, which use turbojet's air pressure for aspiration and provide thrust for high-level cruise flight. Not a very elegant concept, but it might work.
I am thinking about your interesting idea, but to develop a working PDE might take many millions of US dollars, not to mention the danger inherited in the highly pressurized equipments. I am flea sized company, couldn't afford to do anything on this.

As to PDE technology, what I am going to do is take a seat and simply observe those intelligent guys play the game.
Long live jet engine !
Horace
Jetbeetle

Bruno Ogorelec
Posts: 3542
Joined: Sat Oct 04, 2003 7:31 am
Antipspambot question: 0
Location: Zagreb, Croatia

Re: re: PDE engine video

Post by Bruno Ogorelec » Sun Jul 17, 2005 3:11 pm

skyfrog wrote:I am thinking about your interesting idea, but to develop a working PDE might take many millions of US dollars, not to mention the danger inherited in the highly pressurized equipments. I am flea sized company, couldn't afford to do anything on this.

As to PDE technology, what I am going to do is take a seat and simply observe those intelligent guys play the game.
Not my idea at all. That's what I saw in various reports on PDE developments. I know nothing worthwhile about PDEs and they seem as far from ne as Mars, so, like you, I am taking a seat and watching.

Not that I know enough about pulsejets, either, but in this jungle I can at least recognize things, generally move aroundand climb on a tree if I see a tiger.

skyfrog
Posts: 539
Joined: Fri Jul 23, 2004 11:39 am
Antipspambot question: 0
Location: Kaohsiung, Taiwan
Contact:

re: PDE engine video

Post by skyfrog » Mon Jul 18, 2005 5:48 am

I am a good specator, I will encourage those guys targeting PDE research for getting some breakthroughs. But I have seen retardations in the development, meaning there might have been something went wrong. I will be very disappointed if it couldn't be commerialized within 10 years.

I also pay my attention to the development of SCRAM JET, and it seems very promising too.
Long live jet engine !
Horace
Jetbeetle

Bruno Ogorelec
Posts: 3542
Joined: Sat Oct 04, 2003 7:31 am
Antipspambot question: 0
Location: Zagreb, Croatia

Re: re: PDE engine video

Post by Bruno Ogorelec » Mon Jul 18, 2005 9:48 am

skyfrog wrote:I will be very disappointed if it couldn't be commerialized within 10 years.
I will not. It is a tricky technology. PDEs have been known since the 1930s. Paul Schmidt reinvented the pulsejet just before World War II by trying to develop a PDE. Yet, nothing has come out of it so far (as far as we know).

Development of even a much simpler technology until it can be widely used without second thought is generally much longer than people appreciate. Let me give you some everyday examples.

Turbochargers have been around since the 1930s. They only became common in passenger cars in the late 1980s. (I know about Chevy Corvair of the 1960s and the BMW and Saab Turbos of the 1970s, but those were specialty cars; exceptions rather than mainstream designs.)

Four wheel drive (I am talking of sophisticate torque-split systems) has been around since the late 1950s in the brilliant package made by Harry Ferguson, yet it only really made any market impact in the late 1980s with the second series Audi Quattro.

So, even the relatively simple automotive technology takes 30 to 50 years to mature enough to enter mainstream commercial use. PDEs are on a different scale altogether. Even if the prototypes are flying today -- which is anyone's guess -- I doubt we will see a civilian PDE aircraft in the next 30 years.

Mark
Posts: 10743
Joined: Sat Oct 11, 2003 10:14 pm

re: PDE engine video

Post by Mark » Mon Jul 18, 2005 1:22 pm

One thing I was thinking about which is hard for pulsejets, is to use steady mechanical valving, due to the erratic nature of combustion. But perhaps by using the very long tubes in pulse-detonation, the extra length evens out some of the wandering nature of the flame front.
Didn't that one site have a 4 pack of straight tubes like a Gatling gun? I don't know what the chamber looked like but the straight tubes wouldn't be too hard to come by.
On the other hand, it might be fun to see how fast you could drive a smallish sphere with short snorkel in a way to make it bang or backfire loudly when sparked. My 8 inch diameter steel gazing ball with snorkel pipe kicks pretty good like a cannon when I light the tail end. If only it would rapid fire.
I noticed in the one color rendering the duct on a PDE ended in an ovalish shaped small chamber.
Mark
Presentation is Everything

Mark
Posts: 10743
Joined: Sat Oct 11, 2003 10:14 pm

re: PDE engine video

Post by Mark » Mon Jul 18, 2005 5:03 pm

Something that would be quieter to try would be an underwater PDE exhaust of sorts, that is if you could feed fuel and air into your chamber only from the front and not rely on any backflow for help, just have a constant blasting of reactants out the tail end. I think Bruno has a sketch of a water exhaust pulsejet of sorts, just something quieter to experiment with. Might be fun.
Mark
Presentation is Everything

El-Kablooey
Posts: 723
Joined: Tue May 31, 2005 3:39 am
Antipspambot question: 0
Location: Northwest Georgia, USA

re: PDE engine video

Post by El-Kablooey » Tue Jul 19, 2005 6:22 am

this?? I was wondering if this was viable, could be very cool..
Attachments
dr7.jpg
(280.18 KiB) Downloaded 863 times
On an endless quest in search of a better way.

mk
Posts: 1053
Joined: Mon Jan 19, 2004 8:38 pm
Antipspambot question: 0
Location: FRG

Re: re: PDE engine video

Post by mk » Tue Jul 19, 2005 7:52 am

Bruno Ogorelec wrote:I will not. It is a tricky technology. PDEs have been known since the 1930s. Paul Schmidt reinvented the pulsejet just before World War II by trying to develop a PDE. Yet, nothing has come out of it so far (as far as we know).

[...]
The stage of developement of the Schmidt tube ended up to be somewhere inbetween a pulse-jet and a PDE.

The combustion velocities in a Schmidt tube reached times the ones in pulse-jets. Even a similar seeming Argus resonator was not expected and did not achieve the combustion velocities achieved in a Schmidt tube.

Sadly there was some internal canceling of Schmidt's developement going on. Who knows where his efforts would have lead to already? However, doubtful times.
mk

dynajetjerry
Posts: 465
Joined: Thu Jan 27, 2005 4:57 pm
Antipspambot question: 0
Location: Ohio, USA

re: PDE engine video

Post by dynajetjerry » Wed Aug 10, 2005 9:46 pm

I have a nit-picking and unimportant comment for Bruno:

Turbo-superchargers were designed and installed on a few Army air Force planes much earlier than 1930 and tested at Wright Field. Among others, several Curtiss biplanes were tried (predecessors to the beautiful and famous P-6E,) but the turbos were NOT used to boost the power of engines at sea-level, unlike today's automotive applications. The engines' maximum outputs were determined by metallurgy and design and the sole purpose of the turbos were to obtain sea-level power at high altitudes.

During the era of reciprocating engine/propeller military aircraft, engines were rated by manifold pressure @ rpm and these figures were exceeded only at the peril of the pilot. In fact, there were usually 3 ratings applied to each engine: Long-term maximum, take-off, and War emergency, listed from the lowest to the most. For advertising purposes, take-off ratings were usually the numbers that were publicized.

Late in WW II, water injection was often employed to reach war-emergency levels, to reduce a tendency to detonate and destroy the engine. Times between overhaul (TBO,) varied from the listed durations because they depended on how long operation was maintained at each of the rated power levels. However, I heard many years ago that war emergency output was limited to 5 minutes in an almost-new engine. After that, the pilot was to be prepared for a sudden demolition of the engine. Indeed, if a pilot was forced to use WE power AT ALL, he was supposed to land at the earliest opportunity and see that the engine was completely overhauled before it could again be allowed to fly.

Jerry

Post Reply