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Mach Buster Supersonic Turboprop Aircraft

hesham

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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
 

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Kryptid

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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

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Thank you Kryptid,


and was it a real aircraft or fake ?.
 

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Stargazer2006

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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

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That picture looks like a static display piece.
 

hesham

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Stargazer said:
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.
 

Stargazer2006

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hesham said:
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

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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

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Many thanks to Stargazer and Lastdingo.
 

Anderman

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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

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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

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Kryptid said:
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

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hesham said:
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.
 

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AeroFranz

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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.
 

Stargazer2006

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AeroFranz said:
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

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Thank you my dear Retrofit,


and you are right my dear Stargazer.
 

Stargazer2006

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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-chapters/chaptergram-articles/2016-03-the-rest-of-the-story-david-roses-renegade
 

hesham

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Thanks,and welcome your return.
 

Viper2000

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Kryptid said:
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

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Nice find Viper2000,and welcome aboard.
 

riggerrob

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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.
 

nuuumannn

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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

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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

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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.
 
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