Mach Buster Supersonic Turboprop Aircraft

[hesham]

Hi,

Mach Buster is a project to make the first prop. plane that can go supersonic in level flight. This may just be a way-out there plan that will never work. But I have always thought about this, and wonder why it has not been done in the past. I understand that the shape of the airfoil of props might not work at such high speeds, but what about simple turbine blades? Certainly a canted turbine blade can still work at supersonic or even hypersonic speeds. Anyway check it out, I love the idea. I love the 1,230 hp engine. These are good things

http://highpowerrocketry.blogspot.com/2006_10_01_archive.html

 

[Kryptid]

Supersonic propeller-driven aircraft are of great interest to me. I have given much thought over the years to how one might be constructed. I do believe a NASA experiment with a modified Voodoo (XF-88) demonstrated that propellers can generate positive thrust above the speed of sound, but I am unsure of the details. The XF-84H seemed to be an attempt to do the same, but had various problems.

EDIT: Photograph here: http://www.airliners.net/photo/Rose-Mach-Buster/0801827/L/

 

[hesham]

Thank you Kryptid,


and was it a real aircraft or fake ?.

 

[Stargazer]

An engineer who had worked with Burt Rutan and explored the subject with him apparently concluded that supersonic flight wiith a prop other than in a dive was just not possible. I'm no expert but if these guys said so I believe they must have given the idea some good thinking. Consider this: if there had been even a small chance of achieving it, don't you think Rutan would have jumped on the idea?

 

[Avimimus]

That picture looks like a static display piece.

 

[hesham]

don't you think Rutan would have jumped on the idea?

May be my dear Stargazer,


but we deal with this aircraft as a fake design to this moment,right.

 

[Stargazer]

but we deal with this aircraft as a fake design to this moment,right.

No, "theoretical and speculative" is not the same as "fake"!!!

If some aircraft engineer working for the industry decides to imagine a new concept on a restaurant's paper nakpin, it's theoretical.

If some artist designs an aircraft and tries to pass it off as real, THAT is fake!

 

[lastdingo]

Turboprop engines are really just turbojets with a geared propeller.

You can adjust the propeller to minimised drag and have the turbojet powerful enough for supercruise (without afterburner). Alternatively, you could guide the exhaust gasses (thrust) away fromthe rear of the turbojet as was done with the Harrier's Pegasus engine (and nose-installed turboprops in general) and then you could add afterburners to these 2+ nozzles. The propeller would then ned to be fully stopped at supersonic speed to keep the blades away from the afterburner exhausts' path.

It would make no or almost no sense, but in theory it's possible. The result would have a disproportionate weight and volume share allocated to propulsion (as did VTOL designs, for example).

The propeller would be a huge problem, and of no real use at subsonic speeds unless you insist on a huge loiter time at low or medium altitude.

 

[hesham]

Many thanks to Stargazer and Lastdingo.

 

[Anderman]

Back in the day their was a very small article in the german magazin FlugRevue with the same picture and information as the first post.
Always wondered what happened to the project.

 

[Kryptid]

I realize that the transonic zone has a large amount of drag and that at low supersonic speeds the drag is actually less. What if one were to design such a propeller-driven aircraft to be carried by a larger supersonic aircraft, such as a B-1, which would carry it above the draggy transonic regime and release it? Would this be more practical than trying to push through Mach 1 with a propeller directly?

 

[lastdingo]

I realize that the transonic zone has a large amount of drag and that at low supersonic speeds the drag is actually less. What if one were to design such a propeller-driven aircraft to be carried by a larger supersonic aircraft, such as a B-1, which would carry it above the draggy transonic regime and release it? Would this be more practical than trying to push through Mach 1 with a propeller directly?

The propeller stops being a sensible tool for propulsion at little more than 800 km/h at the latest. The Tu-95 bomber flies at about 900 km/h mostly as a turbojet aircraft.

An easy way to break the sound barrier is to simply dive for a few seconds, and turn altitude into velocity (potential into kinetic energy). Even works for parachutists.

 

[Retrofit]

and was it a real aircraft or fake ?.

Registration N104MB has indeed been reserved for this prototype but has now expired. So it is not fake.,
http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=104MB

I found also the following docs (source AWST December 90 but first unkown (EAA magazine perhaps)) of the aircraft still in construction. Design is attributed to Bill Montage, not David Rose.

 

[AeroFranz]

Agree, this was a serious (if doubtfully promising) design which achieved hardware stage. In this regard it does not differ from a lot of other prototypes we discuss in the 'real' projects part of the forum.

 

[Stargazer]

Agree, this was a serious (if doubtfully promising) design which achieved hardware stage. In this regard it does not differ from a lot of other prototypes we discuss in the 'real' projects part of the forum.

I absolutely agree with this. The Mach Buster belongs in the "Postwar Projects" section!

 

[hesham]

Thank you my dear Retrofit,


and you are right my dear Stargazer.

 

[Stargazer]

Why the Mach Buster... busted:

In 1999 David [Rose] bought Mach-Buster, a partially completed airplane whose design was based on high-speed aerodynamic research that had been performed at NASA Ames Research Center at Moffet Field, California. After considerable time and effort to finish Mach-Buster, David and his team determined the design was not suitable for flight testing and abandoned the project.

Source: https://www.eaa.org/en/eaa/eaa-chap...03-the-rest-of-the-story-david-roses-renegade

 

[hesham]

Thanks,and welcome your return.

 

[Viper2000]

Supersonic propeller-driven aircraft are of great interest to me. I have given much thought over the years to how one might be constructed. I do believe a NASA experiment with a modified Voodoo (XF-88) demonstrated that propellers can generate positive thrust above the speed of sound, but I am unsure of the details.

Here is a research memorandum on the performance of the supersonic propeller fitted to the XF-88B; it includes data at flight Mach numbers up to & including 1.01:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930090296.pdf

 

[hesham]

Nice find Viper2000,and welcome aboard.

 

[Basil]

Very interesting link, thank you!

 

[riggerrob]

Few jet engines have internal supersonic flow. A major factor in jet engine inlet design is reducing airflow to slower than Mach 1.
Late in the process, they may add an afterburner with supersonic exit speeds, but afterburners are much simpler, without turbine blades. Afterburners are glorified rockets installed in the tail pipes of regular gas turbine engines.

 

[hesham]

From L+K 26/1993.

 

[nuuumannn]

Turboprop engines are really just turbojets with a geared propeller.

Not really, while the means of driving the prop is achieved the same way as driving a turbine, the thrust comes entirely from the propeller, not the hot stuff coming out the back of the engine. This is the case with turboprops in general use today, your PW100 series and PT6 engines anyway. Bigger things, like the Allison T56s and the big Russian ones driving the Tu-95 have an element of thrust from the hot end, the majority is thrust from the whirly bit at the front.

The same in fact from a high bypass turbofan engine, where in the most modern engines, some 90 percent of thrust is generated from the 1st stage compressor, the big fan at the front.

A lesson might be learned from the Republic XF-84H Thunderscreech, the loudest aircraft in history!

 

[archipeppe]

McDonnell XF-88B, which mounted an Allison T38 turboprop (but retained its jet engines) dimostrated, even if impractical because achieved at the end of a dive, the propeller supersonic flight.

The Republic X-84H failed to be supersonic while the Tupolev Tu-95 "Bear" has an awesome speed of 800+ Km/h.

 

[nuuumannn]

while the Tupolev Tu-95 "Bear" has an awesome speed of 800+ Km/h.

Yes, an amazing presense of an aeroplane, but on take off and flying at speed, the noise is extraordinary.

 

[ZacYates]

A friend recently gave me a collection of Aeroplane Monthly back issues. The December 1988 issue includes coverage of that year’s Oshkosh, where the Mach Buster was (first?) shown. A black and white version of the concept art earlier shared by Hesham is included, as is the following text:

A possible competitor to the Pond Racer at future air racing events is the Mach Buster, designed to become the world’s first propeller-driven aircraft to break the sound barrier in level flight. Similar in outward appearance to a Northrop F-5, it is fitted with a supercharged V8 racing engine which will power the aircraft through a scimitar-blades, high-speed propeller mounted behind the tail surfaces. The Mach Buster is now 80 per cent complete, and arrival of the airframe at Oshkosh created enormous interest. The team is confident that technology created for the propfan aeroengine can be successfully employed to run propellers efficiently at supersonic speeds. After a world record speed attempt, the Mach Buster will take part at Reno and other Unlimited-class air races. Skip Holme[sic], who has already won twice at Reno, will fly the aircraft and he is currently predicting average lap speeds of over 540 m.p.h. “It looks entirely possible to break the sound barrier coming down the straight leg towards the grandstands,” Holme said, “but it will be tough keeping in bounds on the 500 m.p.h. turns.”

 

[hesham]

Thank you ZacYates,

and if there is un-released or never displayed pictures or drawings here,please send it.

 

[riggerrob]

Turboprop engines are really just turbojets with a geared propeller.

You can adjust the propeller to minimised drag and have the turbojet powerful enough for supercruise (without afterburner). Alternatively, you could guide the exhaust gasses (thrust) away fromthe rear of the turbojet as was done with the Harrier's Pegasus engine (and nose-installed turboprops in general) and then you could add afterburners to these 2+ nozzles. The propeller would then ned to be fully stopped at supersonic speed to keep the blades away from the afterburner exhausts' path.

It would make no or almost no sense, but in theory it's possible. The result would have a disproportionate weight and volume share allocated to propulsion (as did VTOL designs, for example).

The propeller would be a huge problem, and of no real use at subsonic speeds unless you insist on a huge loiter time at low or medium altitude.

Dear lastdingo,
Rolls-Royce, Hawker and McDonnell-Douglas devoted thousands of hours to adding plenum chamber boost/burning to Pegasus engines, but never succeeded. They were trying to improve thrust and lift for vertical takeoff.

 

[Nik]

"...plenum chamber boost to Pegasus engines..."

Circa 1990, I met a Mr Rowe, then of Stockport, who'd worked on the 'supersonic pegasus'. He led the 'Tiger Team' which came in after the regulars had striven mightily yet failed. He said his small group managed to solve it in a remarkably short time. Sadly, when they reported their improbable success, they were told that the project had just been cancelled, EVERYTHING to be destroyed...

I'm sorry, despite the passage of time, he still considered himself bound by 'NDA'. Beyond a very rude expression when I mentioned 'plenum burning', he declined to discuss it...

We met via his wife Pam, who bred & judged Siamese cats, of which we had several. Mr. Rowe had left the aero-industry in disgust after the super-pegasus debacle. He'd down-skilled from jet engines to drafting house-extension plans, was the only member of his team still in fair health...

I'm sorry, I forget his first name, even his affiliation. I did some research, was unable to trace him. All I remember was both their sons went into 'Engineering'...
YMMV.

 

[dannydale]

project had just been cancelled, EVERYTHING to be destroyed

This is apparently a fetish for the British government. This happens uniquely far too many times in British aerospace to be happenstance or coincidence.

 

[Zoo Tycoon]

I was at Rolls at this time but not on the PBC team (I was on Team Tandem Fan) . The PCB guys were told to get on with some practical testing when they found an old BS100 in scrappy. This progressed at Shoeburyness with a chopped about Harrier and Goliath crane. It was undertaken with commendable swiftness. However the crunch came when it was realised the frontal area of the LP fan really wasn’t compatible with a supersonic airframe. So PCB was dropped and the focus went to Tandem Fan, RALS(a) & RALS(s) . I left when Tandem Fan was dropped and in the end RALS(s) won the day, ref F35B.

People misinterpret the “destroy all paperwork” thing as some deliberate malevolent act when it’s not. During one of these projects there’s masses of paperwork, most of it copies of sensitive documents. After a stop work this mountain of unwanted paperwork becomes a security liability.....,so engineers/others see it being methodically collected up for destruction and being a bit depressed assume they’re the victim of a wider conspiracy. The original reports are generally kept, although as time passes the archive can thin down as a result of commercial storage space needs or something like a fire (yes, some does get thrown away due to haphazard ignorance). I’ve spent many a happy hour in the archive and found all sorts of things which popular myth assured me as having been destroyed.

 

[Nik]

IIRC, Mr Rowe dropped some fairly rude hints that there were 'TransAtlantic Considerations', as the US really, really did NOT want UK selling comparatively cheap super-sonic 'Jump Jets' that did not need mega-bases or mega-carriers, that could VIFF the sox off traditional fighters' guns, missiles etc etc.

That the US Marines would have loved such capability, probably added insult to injury, given they'd totally up-stage both USAF and USN...
Of course, like eg Avro Arrow and TSR2, YMMV...

 

[KJ_Lesnick]

@Nik ,
Trans Atlantic Corporations?

 

[Hobbes]

Dear lastdingo,
Rolls-Royce, Hawker and McDonnell-Douglas devoted thousands of hours to adding plenum chamber boost/burning to Pegasus engines, but never succeeded. They were trying to improve thrust and lift for vertical takeoff.

As I understood it, PCB worked but was found to be impractical due to the massive ground erosion it created.

@Zootycoon that airframe used to be on display at the Bristol Collection, and is now going to the Hucknall Flight Test Museum.

 

[Zoo Tycoon]

IIRC, Mr Rowe dropped some fairly rude hints that there were 'TransAtlantic Considerations', as the US really, really did NOT want UK selling comparatively cheap super-sonic 'Jump Jets' that did not need mega-bases or mega-carriers, that could VIFF the sox off traditional fighters' guns, missiles etc etc.

That the US Marines would have loved such capability, probably added insult to injury, given they'd totally up-stage both USAF and USN...
Of course, like eg Avro Arrow and TSR2, YMMV...

Ah the old chestnut of the Americans being terrified of Brit ingenuity they had a word In the right ear and killed its industry.

What really happened was in about 1985 the P1214/16 was canned when HMG decided the U.K. couldn’t afford to solo fund a military aircraft program with little chance of commercial success (boring I know). So multi partner projects were “the only port in a storm”, and, sadly UK critical technical capability (the type you only get from running a whole project) was allowed to wither away. A few years latter, I was Tandem fanning, it was widely known across the wider engineering team, inc those on PCB, that the effort was aimed ay an eventual US partner project (This was about the time I first heard JSF or was it JAST?). No different to the large IPT that was then working on the quad-party EJ200. Against this background I’d be very surprised if there was anybody who continued to believed the U.K. could still go it alone.

I remember seeing the sub scale & luminous orange P1214 model which remained installed in the hot recirculation rig despite being 3-4years after cancellation.

Yes the PCB chopped Harrier is the one at Hucknell. The PCB rig was to investigate ground erosion and hot gas recirculation. From memory PCB had the following unsolved issues,-
I) high rate of ground erosion
2) wide girth, = poor supersonic drag
3) unsatisfactory safety case:- stable combustion required in three zones with a catastrophic outcome in the event of a single point failure in any one.

I would love to know how the chopped about Harrier rig could have shown a solution in any of the above.

 

[Nik]

Sorry, Z, all I know is Mr. Rowe described a 'Eureka' moment, when the [REDACTED] pieces just fell into place. Given that test rig, he must have been aware of ground erosion and re-circulation issues, flame stability etc etc. All nasty stuff that had thwarted his predecessors. Besides, his mini-team's elegant 'design fix' never reached the hardware stage...

Sadly, unless something relevant is declassified from the 'National Archives' or 'Patent Office' circa ~2035, we may never know for sure if they'd really found a workable fix, or just a mirage....

IMHO, given you don't recognise his name, there are 'unknown unknowns' in the project history.
{ Shrug... }

 

[Zoo Tycoon]

2035 ? No;- Patents are published after two years (the protected period is 20 years and publication is essential to the way the system functions ) and U.K. National archives 20 years, unless subject to specific FOIA exceptions. FOIR can be made against older exception and are frequently granted;- ref Freedom of Information Act 2000.

Given these events occurred in the timeframe of 1980-1990 it should all be out there.

 

[dannydale]

I'm wondering if we should have this thread split to its own 'Pegasus engine plenum chamber burning' topic?

 

[Motocar]

Good for speculative cutaway drawings... Dates... dates...? Motocar