Aerodynamics of Supersonic Craft

Supersonic Glider-spacecraftSupersonic Shock Waves

by Robert Brand

Phase 1 Test Craft

As you all know by now, Jason, my 12 year old son, will attempt to break the sound barrier mid year – he will be 13 by then. This is the first test of a high drag system that should limit our airspeed at supersonic speeds. It is the Phase 1 testing that we talk about in our documents. We need to go fast for this experiment, but returning from space we need to slow down. Our transonic tests will be with a very different looking craft than our future spacecraft.

To the right, you will see where Jason’s design started. As you may have noticed, the ThunderStruck’s current design looks nothing like the image to the right. At each stage he has had to modify the craft to achieve the goals of going supersonic and get up to around 2,000kph ThunderStruck Design and 1-2 size measurementswith full stability. Only then will we deploy the experiment and hopefully slow the craft dramatically. As you are aware, it now looks more like the craft to the left. These are massive differences and we will explore the choices he made in another post. Right now we are looking at how we get rid of the major shock waves and also how our Phase 2 test aircraft may look. The main differences in the 2 craft are:

  • No supersonic Spike
  • No central tail
  • Winglets above and below with a ganged rudder
  • Delta wings that have two angles of protrusion from the fuselage
  • Elevators and ailerons are at the rear of the wing
  • The wing extends to the rear of the craft

Phase 2 Test Craft

In Phase 2 the craft that we design will need to travel straight up into space on a sounding rocket. We will separate from the rocket and continue our climb (momentum) to apogee (top of the flight) and then fall back to earth. Apogee may be as high as 200km. The air is so thin that we can conduct what we call weightlessness experiments for several minutes. Once the air starts to create drag, the experiments will end as the craft will slow. At this time we do not want the craft to accelerate further, but it will. Unless we feather the wings(like Virgin Galactic’s Spaceship 2) or create massive drag in some other way (our Phase 1 experiment) we will go too fast for our craft’s well-being. We need to go slow as possible. We do not want to have to slow with unusual braking as this may de-stabilise the small craft.

Hyabusa reentry sequencWe could use a capsule, an ablative heat shield and a parachute like JAXA’s Hyabusa, but we are creating a winged vehicle, although the capsule will always be another option. I guess the cat’s is out of the bag. We will have a couple of configurations possible with capsule or winged reentry as an option. The ThundrStruck craft will be a modular design in the style and electronics. The picture to the right is the landing sequence for JAXA’s Hyabusa that landed in the centre of Australia. It is not complicated, but you do have to know what you are doing and the downside is that it lands where ever the winds take the parachute.

I want to fix that problem for those customers that need a precision landing or effectively or a smooth landing. I would love to be able to direct the returning spacecraft to a point on the map that allows us to land it without having to recover it from an unknown place in the desert.

Supersonic Aircraft SpikeThe picture at the top of page is where we started. I expect that the spike will not be on the spacecraft and it is also now unlikely to be on the transonic test vehicle, but it is important to understand why we see them on supersonic craft. Sometimes a very long sharp nose can also produce the desired effect.

The picture at right is a NASA test vehicle with a spike. There are many supersonic aircraft that either have a spike of a very sharp nose well ahead of the wings. Why? We discuss this after the following paragraph.

Returning from space the spike would be a liability in the heat of reentry. It will also not be an asset in slowing down a craft. We only need to have the spike as an option to help lower the Resistance to breaking the sound barrier for our tests. At the time of posting, Jason has gotten rid of the spike and opted for wings tucked back behind the shock wave.

In our tests we will use gravity to accelerate the test craft to way past the speed of sound, but shock waves (pressure waves) would slow us down and limit our top speed. We would probably still break the sound barrier dropping the craft from around 40km altitude, but the quicker we transit the sound barrier the higher our top speed and the better the results from our experiment.

So What Does the Spike Do?

supersonic shockwaves in a windtunnelAs I said a sharp nose is the same as a spike and the image to the left shows the effect of the nose/spike as it moves the shock wave to a point well ahead of the main body of the craft and away from the wings. A sharp point is a very low area of shock and in the image you can see the shock waves from the wings as very low level compared to the shock from the tiny front of the aircraft. So long as the wings are tucked in behind the initial shock wave than the drag is lowered considerably. The reason that it was so hard to break the sound barrier was simple. The craft used had their wings in the high drag area caused by shock waves.

Now I may have been a bit simplistic here, but none the less, the spike is important to supersonic flight. Since we are wanting to slow down in Phase 2 tests returning from space via a sounding rocket, we can actually round the nose of the returning spacecraft and still get the supersonic shock to clear the wings

So Why Didn’t the Shuttle Need a Spike?

WPointy nose and shockwaves at mach 6.ell it did need to slow down and so you might think that a blunt nose is a good thing to create drag, but that is not the reason. Wouldn’t a sharp nose be good for takeoff, spike or no spike? Well, in some ways, yes, but the shuttle had wings that were very wide and a spike could not be placed that far forward. The resulting shock waves on takeoff and especially re-entry would be a bit problem as they would hit the wings.

Re-entry would be the biggest problem. The shock wave from a sharp nose would hit the wings and further heat the air. You would be adding thousands of degrees to the heat that it is already being generated on the leading edge of the wing – not a good idea! See the image above right. This would be a poor design for such a craft. The image shows a pointy nose model in a mach 6 airstream. You can see the shock waves hitting the wings midway along their leading edge.

So What Happens with a Blunt Nose?

The image to the right says it all. The blunt nose acts as a ram and pushes the shock wave way to the sides. This misses the wings by a long way – and the tail of course. The blunt nose does add to drag so that is another benefit to slowing down, but a minor one. It is the additional heat caused by the shock wave over the wings during re-entry  that had to be eliminated

What Else Protected the Shuttle from Shock?

Ever consider the orange main fuel tank? Where was the shuttle positioned relative to its nose. It had a point, but was really broad.

What effect did that have during launch at high speeds. The shock wave that resulted missed the shuttle entirely. It is important that the top of this tank was far enough forward to protect the shuttle. The whole design and shape of the combined modules on the launch vehicle was super critical and not just a random bunch of sizes. Minimizing shock waves means being able to both protect the vehicle and increase the payload as you have less drag.

In other words, if the main tank had needed less fuel and had been smaller, then it would still have needed to be as high to push the shock waves aside.

Each and every part of an aircraft that changes its size or sticks out causes shock. You must account for it or suffer the consequences.

The image at right clearly shows the shock wave of the jet disturbing the water. You do not have to be traveling at supersonic speeds to produce shock waves, but the faster you go, the more power is lost and the stronger the shock wave.

New Doors are Opening Every Day

Spaceport AustraliaKicking Open Doors to New Adventure

If you don’t spend the time getting the word out about a project dear to your heart like ThunderStruck, you will stall and fail. It takes the right contacts and the right people to make a project successful. We are certainly at that point of critical mass right now.

ThunderStruck will be the sonic boom heard all over the world. It would be crass to say “The Thunder from Down Under” so I will resist the opportunity.

Door 1: I recently posted in a number of new places including a lot of suitable Linkedin Groups and they certainly produced results and for all parties, not just ThunderStruck.

I received many comments on the posts and some have been exceptional.

Add to that the interviews on radio, print and on-line media and the results have been spectacular. Here is an ABC news article that certainly got new attention all over Australia:

Click here to read the article

Door 2: Another has been an article in the UK based The Register.  This has been an amazingly popular 2 page story that gained global recognition for the project.

The Register

Spaceport AustraliaSpacePort AUstralia (SPAU)

Door 3: This is one such organisation run by a man that has caught my attention. He is not well known in the space sector and is more of a business man, but he is dedicated to building a spaceport here in Australia and I believe that he will succeed. He is looking in Queensland and believes that he may have found the airfield that may become our first spaceport. John Moody is his name and the company is Spaceport Australia. John has connections in the music business and I am hopeful of some great connections for ThunderStruck. You can find out more about Spaceport Australia and we will be posting more stories about John and SPAU regularly.

Click here to Visit SPAU

More to Come

There are more big opportunities on the way and we have to get signatures on legal documents before I can speak about them. None the less if you are interested in taking a small shareholding in the business side of things, I can discuss the upcoming opportunities.

 

What a Week for ThunderStruck

A Lot can Happen in a Week.

It has been a massive week for ThunderStruck. We have had important meetings, been in the press, had interviews, got published with a big article in the UK Register, set up two possible JVs or at least mutual support opportunities, designed the final (as can be) configuration of the Phase 1 airframe, responded to numerous inquiries, published some pages, sent letters, discussed issues with the project and the end is not in sight. it seems that we are getting so much interest, that we will need more feet on the ground just to respond to interested people. And we do meet interesting people

Michel FournierMeet Michel Fournier

He is one of those great guys that wants to axctually JUMP from 40Km up. I’m not doing that and neither is Jason – well, not at the moment, anyway. We are supporting him and his mission for the simple fact that, in his words: “Why not in 2015 , the youngest and the oldest stratonaute ?”

8a2ffd5c-0390-11e3-8965-22000aa5129e-largeDid you notice a French spelling? Michel comes from the Marseille area in France, an area of the world I do love very much. His project is called “LE GRAND SAUT” which means of course, “THE BIG JUMP”.

Michel says: “I am currently being prepared of a jump to 40,000 meters, the objective to find solutions with the major challenges of space voyages. More than 9000 jumps to my credit with a jump from 11,898 meters”.

Well Jason is only doing this by remote control, but Michel has the drive to be up there, doing it for real. You have to love it. Below are some photos of pressure testing and test jumps. Stay across what Michel is up to and we will report it occasionally too.

26ff3cc0-f7b0-11e2-86ca-22000aa5129e-large

7169f7d8-f7af-11e2-896a-22000aa5129e-large

95ddb064-f7af-11e2-9751-22000aa5108a-large

You can check out Michel’s Linkedin page here:

https://www.linkedin.com/profile/view?id=227598270

Michel also says:

“Please check out my project : www.the-big-jump.com to know my project better and I thank you for your interest in my project.

I have a budget in Research also, in testing and production equipment of 11 million € 800 , I have tried unsuccessfully because of the balloons and lack of funding. Today I have a new balloon manufactured by the US, which should allow me to easily cross 45,000 m. For this, I must still find 1 million € to achieve it. I am looking to research for partners. All of my communications and my marketing are free. I have permission from the Canadian authorities. ”

As for progress on the other ThunderStruck activities, stay tuned for those announcements in further posts at Project ThunderStruck.

 Anyway, for the moment, Jason will have to be content with being a virtual “stratonaute“. Good Luck Michel.

 

 

Unveiling Phase 1 ThunderStruck Design

ThunderStruck Design and 1-2 size measurementsTransonic Test Design

In the first phase testing of our ThunderStruck spacecraft, we want to go fast so that we can test some “drag” experiments. As such, the airframe proposed looks nothing like what our spacecraft design will probably resemble. After all we wish to slow down returning from space, not speed up.

Below are the design shapes and dimensions for a 1/2 size model of our flight aircraft. Why 1/2 scale? Simply, a full scale mockup would be too big to fit into my car!

After looking at the figures our modeller has recommended that we actually use a 1/3 size model as the 1/2 scale model is too big to fit his lathe! We will talk about the design in another post. I just wanted interested people to have a look at the craft ASAP.

The final craft may have a supersonic spike that will double as a VHF antenna, but it will not need a spike. The wheels will have brakes to stop them spinning during flight. There is a lot to do yet, but we are enjoying the challenges. Note that we may tweak the design further plus I have not included the canards for subsonic flight. They will deploy slowly as we slow the craft. They will not deploy until the craft is subsonic.

ThunderStruck Design and 1-2 size measurements

Above are the dimensions for a 1/2 size ThunderStruck airframe.

 

Becoming a Stakeholder in ThunderStruck

stakeholders

stakeholders

ThunderStruck Stakeholder.

Want to help create a spacecraft with a purpose? Wish to See Australia as a major contender in space exploration? Want to see more jobs in the space sector here in Australia. If you answer Yes to any of these, please consider supporting this amazing endeavour.

We are entering fundraising mode soon and one of the things that we have to offer is being a stakeholder in the future ThunderStruck spacecraft. Currently we are looking to form a company to develop the concept and to partner with other organisations. At this time, there is a serious interest from one Sydney based University that may result in a partnership arrangement with opportunities to take on interns to help in the development of concept craft for flight testing.

As you know, ThunderStruck will be designed around the concept of a winged spacecraft. It will be the smallest spacecraft that can re-enter the atmosphere with stability and fly to a landing. It will be in two models – a sounding craft (straight up and down – no significant heating) and a low earth orbit re-entry vehicle. It is designed to carry approximately 50Kg of payload. A third model may be built that will be a capsule with a standard heat shield (like the Orion capsule). This will be capable of surviving re-entry from a direct approach to earth without orbiting first. The main thing is that the systems will be standard. The craft will have an optional Ion engine and also a high deltaV maneuvering system – essential for de-obiting to a precise location.

It is not expected to accept anything smaller that 0.5% shareholding for an amount of $1,500. The dollars brought into the company will be rolled into the development of the three concept vehicles along with sponsorship money and crowd funding. Money earned from video rights, magazine rights and other media opportunities will also be rolled into funding the future craft. Speaking opportunities will not be considered to be part of the company’s income.

Following the second phase concept flight test, it is expected that we will have a sounding rocket based solution for experiments sent to space and back. This will be in about 2 years time and money may be earned at that time from sounding flights producing several minutes of “weightlessness”.

An orbital re-entry solution will take several years more to develop. As little as two years or as long as four years depending on funding and any hurdles discovered in test flights.

It is not expected to allow any more than 20% of new shareholders and at this stage, 2% has already been sold. The above are not rules and not fixed in stone but are simply an outline of what is happening. Please contact us for more information if you are interested. If you have the right qualifications, you will be considered for employment in the future. There is a clear opportunity to become a director in the company.

Phone 0448881101 for more information. If not answered, please leave a clear 10 second message so that we can prioritise your call. This is not a prospectus or an offer. You need to find out more and ensure due diligence is performed. We will both decide if proceeding is suitable.

Australia:  0448881101      or Int’l:  +61 448881101

Equipping our Tracking Vehicle

Pajero Centre ConsoleTracking Equipment and Mobile Technology

One of our big issues when working with balloons and supersonic gliders is that they never stay still. Even our balloon flights have reached an astonishing 230kph over land by simply climbing through the jet stream. Basically, the car can’t keep up. Even if we could travel at such mind-blowing speeds, we could never follow the same path and have to stick to roads that crisscross the landscape and never in an easy route across country. Mind you a recent flight did travel straight along the Mid Western Highway and have the courtesy to land within a few hundred metres of the main road in sheep grazing paddock. – no crops and no trees.

Simply we need to have not just good tracking, but great tracking. That is where the car needs to be able to cater for several technologies and that means radio and wireless data connections. Our car has just this capability and we need more. We have chosen a Pajero 4WD as we will need some rugged ability for off road work. In the past we have had to drive right through a 200m bit of forest without any road or fields that may have had animal burrows. over logs, through streams and much, much more. The Mitsubishi Pajero Escape is an older model, but still good and we have used it for balloon flight tracking in the past.

In Australia, the most common tracking for High Altitude Balloons (HAB) is via either HAM radio APRS for non commercial activities and RTTY on UHF for commercial activities.

Our Kenwood D710 radio sits on the central part of our dashboard in the car - easily able to display where we have to head.

Our Kenwood D710 radio sits on the central part of our dashboard in the car – easily able to display where we have to head.

Ham Radio APRS

APRS stands for Automatic Packet Reporting System and is a digital communications information channel that is capable of handling information such as GPS (Global Positioning System) data. This is ideal for tracking balloons. Ham radio hobbyists simply build receivers and port the data to a central server. Several receivers may pick up the signal and port the data which i recorded in the database. In our case every 20 seconds. The frequency of the reporting interval is important as the payload gets near the ground so that the radio can easily be located. In some areas there are no receivers and internet connections  – known as iGates. Care needs to be taken, but the solution is to have a mobile iGate in the car if there is good mobile wireless coverage in the area. We are preparing to have a mobile iGate in the tracking vehicle. Until then we have a high power APRS repeater. It receives the data and resends it to an iGate that is in range. Occasionally this is in another of our tracking vehicles and the ability to relay is important.  If you want the full details, you need Internet connectivity in your vehicle, either through a tablet or PC.

UHF RTTY

In Australia, it is illegal to use APRS to track commercial flights. We have to use something like the globally accepted UHF RTTY system. RTTY in Australia can be on multiple channels on 434MHz. and can only be 10mW of power. This is fine if you have height and can track to the ground. As with APRS, you need to be nearby when the unit is near the ground or the curve of the earth will cause the signal to be lost possibly 1Km above the ground. on a windy day this can lead to a big search area. Similar to APRS, there are many people that place a UHF RTTY gateway in their vehicle and gate the data to an internet server. If you want the full details from the server, you need Internet connectivity in your vehicle, either through a tablet or PC.

What is Installed in the Vehicle So Far?

Let’s do a list of the basics:

  • A Kenwood D710 APRS capable transceiver (VHF/UHF) with tracking display and GPS integration
  • An Icom IC-7000 all band HF/VHF/UHF transceiver that is RTTY capable (but does not display tracking)
  • An 80 channel CB radio on UHF (in case we have a non ham radio car in the group
  • A Byonics MT-400 10W APRS Beacon
  • A wireless mobile modem with a wired and WiFi router (so to have an external antenna) runs of 12 volts
  • A motorised antenna raiser – the big antenna hides in front of the roof rack and is near invisible.
  • A multi-socket cigarette lighter system for power for many items

What we need to be installed

Let’s do a list of the basics:

  • HF radio antenna (we have the Icom -700 HF radio side hooked into a 100w termination for safety)
  • An auto-tune system for the HF radio
  • Another big VHF/UHF  antenna with a motorised lifter.
  • 2 x 900MHz antennas
  • A 900Mhz antenna for 56Kb modem access to the balloon and ThunderStruck systems
  • Radio Controller as used for flying model aircraft
  • A video downlink on a band to be decided.
  • A visor and screen display for the video from the balloon payload and ThunderStruck aircraft.

So we are already halfway there, but still have a long way to go and need your help with funding. More on that soon. It is clear that we have a lot of this gear tested and bedded down and that is a good thing. Part of my requirements with this vehicle is to make it inconspicuous. Being old is a start. Hiding all the antennas is another. One antenna is super thin and near invisible, another is very short and the last folds down in line with the roof rack. The photos below show the antenna folded down and raised.

Antenna folded down

Antenna folded down

Antenna being raised

Antenna being raised

Antenna fully raised

Antenna fully raised

The fully raised antenna

The fully raised antenna

The antenna can be raised when driving and it lets us enter car parks without a second thought. We have a switch on the centre console, but i am thinking of adding a proximity alarm in case we forget that it is up. That is the switch to the right of the cigarette lighter. Sorry for the debris under the switch. We had just finished installing the Icom IC-7000 above it.

Centre console antenna switch

Centre console antenna switch

The passenger's side of the centre console with the CB radio and the 3 socket cigarette lighter extension unit

The passenger’s side of the centre console with the CB radio and the 3 socket cigarette lighter extension unit

The 10W APRS unit with the GPS receiver to the left of the transmitter

APRS 10W tracker with the GPS receiver to the left of the transmitter

In the picture above, we could have mounted the unit under the dashboard, but it is a little more versatile being  accessible. I also took the opportunity to hard wire the GPS Navigation unit directly to the car wiring. Since the 12 volt plug has the 5V system, we ensured that the charge unit from the plug was in circuit.

The IC-7000 in RTTY mode

The IC-7000 in RTTY mode

Note that I did not change the frequency to 434.650MHz or similar frequency where RTTY resides. I just wanted to show the fact that it does RTTY. The output at the back of the radio connects to an interface box and can then connect to your PC.

Pajero Centre Console with the Kenwood D710 on the top and the IC-7000 at the bottom of the console.

Pajero Centre Console with the Kenwood D710 on the top and the IC-7000 at the bottom of the console.

Note that the IC-7000 display is only a front screen. There is a cable to the base unit under the driver’s seat. it is wired so that the microphone and front screen can be moved to the rear seat so that an operator in the rear of the car can operate the unit. Similarly the base unit for the Kenwood is also under the drivers seat.

Kenwood D710 display  on the centre of the dashboard

Kenwood D710 display on the centre of the dashboard

Note that the unit above has its GPS hard wired. Like the IC-7000, it is a dual VFO. Only the B VFO is displayed above, but you can operate the VFOs on different bands or channels. It is very versatile.

Our Kenwood D710 radio sits on the central part of our dashboard in the car - easily able to display where we have to head.

Our Kenwood D710 radio sits on the central part of our dashboard in the car – easily able to display where we have to head.

The image above is displaying the rough compass direction to the station displayed. It shows an actual bearing (325 degrees) to the target and there is also a distance in 100m increments. Since the beacon was very close, it shows 0.0Km. A second display shows position altitude and speed.

Mobile Wireless modem, router and WiFi hotspot.

Mobile Wireless modem, router and WiFi hotspot.

Finally the above shows our mobile hotspot unit. It still needs its external antenna for really good mobile coverage, so it is temporary. It uses the rear 12 volt outlet next to the torch (bottom left) for power and once the antenna is installed, the modem will not be on the cable, but plugged directly into the TP-Link unit. We also have 4 hard wired network connections for future units such as the mobile iGate.

Also note that there are two other trackers on board that I will not disclose. It has significant anti-theft devices and tracking, so don’t come after this car. it might just get you caught.

Anyway, we are halfway there for Project ThunderStruck. We are extremely ready for any High Altitude Balloon flight.