The P-38 is not like many planes in World War II. It had twin booms. Twin boom aircraft are among the most stunning looking and intriguing aircraft. It seems that reasons for having a twin boom rather than a mono-body are varied and have little to do with aerodynamics. This configuration allows for rear cargo doors, a push propeller, rear observations or electronics, stable overall frame, central exterior cargo, and other things that I can't think of. When your designing something and you start to look at the numbers, different characteristics are desired over others based on the desired role of the aircraft. A twin boom design might just flip the bill. Let's check out a few of my favorites.
P-38 Lightning
P-61 Black Widow
World War II was an interesting era for aircraft design. The P-38 and the P-61 had similar twin boom configurations. Their crews were housed in a central nacelle set between the two booms that housed the twin prop engines. In the case of the P-38, there was seating only for one and all the guns and cannons were directly in front of the pilot. No propeller interrupt was needed. It was designed as a high altitude (20,000 ft.) interceptor. It featured a large rear elevator, a large wing area, and a twin boom design. The twin booms were ideal to keep structural integrity and low weight. It was successful in its missions and had a number of variants and upgrades. The P-61 was a night fighter that had a crew of 3 and would be in flight for 8 hours. It was used to hunt bombers, and had a newly developed aircraft radar system. Such equipment for that era was large and heavy. On top of that, this plane was armed to the teeth. It was classified as a fighter. The rear of the middle nacelle was where the radar guy sat. Jack Northrop made the initial design and gave it its twin booms. I wish I knew why.
There were some cargo aircraft of this configuration. Now, they are all but abandoned. One in particular starred in the 1965 movie Flight of the Phoenix. The plane was the C-119 Boxcar. It had a large central nacelle where cargo and crew were. The rear of that nacelle featured large doors that opened to the sides. Now cargo planes have a very different design for the rear doors that allows for more traditional craft design. In the movie, the plane crashes and the survivors make a new plane using one engine boom and attaching the wings to it. I do recommend the movie. A remake was made of it in 2004, but I like the original.
WhiteKnightTwo
He 111 z
The strangest of the twin booms are the twin fuselages. These are used for various reasons. These differ from the P-38 design in that the elevators are not joined. One I like a lot is the Heinkel 111 Z. It was a makeshift of two Heinkel 111s that were joined together by the main wing. A fifth engine was added in the middle. The purpose of it was to tow the biggest glider of World War II, the Me 321. I found some great pictures of this aircraft in a french web site (click here, Google translated here). Its definitely one of the more unique aircraft. In modern times, Scaled Composites created a mother ship to launch a rocket spaceplane into suborbital heights. The plane was the WhiteKnite. It featured twin booms, a middle nacelle for cockpit and engines. The main wing raised from the booms to the center in order to give clearance to the main cargo, the space plane. Burt Rutan designed it and came up with it out of neccesity and speed of manufacturing. They were in the Ansari X-Prize competition, and ended up winning. The descendant of this plane was WhiteKnightTwo. This had twin fuselages and was a more concise design. Its purpose was also to carry a rocket spaceplane and be able to launch it form altitude. At the time of its construction, it was the largest all composite aircraft to date. Another twin body mother ship was the proposed aircraft of Stratolaunch. Stratolaunch want to launch medium sized space launchers from the air. The mother ship would be the biggest airplane by wing span. There's a lot of things to be done before such a vision becomes a reality.
O-2 Skymaster
OV-10 Bronco
In the category of observation aircraft, we have the O-2 Skymaster and the OV-10 Bronco. The Skymaster was from a civilian aircraft. It featured two props, a puller and a pusher. The booms were really skinny and just made to work around the pusher prop. The US used this in the Vietnam Conflict as an observation platform. It would track enemy ground troops. It was featured in the movie Bat-21. That was a really good flick. One of the problems with it is that it was shot down by small arms fire. In later years, the US Air Force acquired the OV-10 as an observation platform. This craft was rugged. It could land anywhere, and it could short takeoff as well. It featured a design like the P-38, but it could carry 2 people and had a small cargo hold. So it could resupply a small ground troop unit in the bush. It did have ejector seats, but you'd better be wearing your helmet because your going to crash through the cockpit class. The glass did not eject. I bet it hurt.
Wow! There's a lot of these twin boom aircraft. From the P-38 to the modern WhiteKnightTwo, it seems these configurations aren't going away. There are even unmanned aerial vehicles with twin booms. This types of aircraft have a multitude of uses. I believe they are a prime example of what makes airplanes so great.
Today there are not many flying boats left in the military. The era of the flying boats was between the world wars. The helicopter took much of the duties of the flying boats. Flying boats were very utilitarian in their time and gave a means of transportation of cargo and passengers faster than any sea vessel. Airplanes needed flat fields or runways, but flying boats could land anywhere there was water. 'Landing anywhere' concept is what made these aircraft so special and needed. There were many flying boats but I like to look at a couple of my favorites, the PBY Catalina and the DO-24.
The PBY Catalina (Cat) was manufactured by Consolidated Aircraft. It was developed in the 1930's and became famous during World War II by taking on a long list of roles. It was a cargo plane and a sea rescue plane. It was a bomber and it was a medical plane. You name it; it probably did it. I fell in love with this plane when I had a model of it. It had exquisite lines, retracting floats and landing gear, and rear bulbous windows that served both as side guns and in water exit and entrance to the craft. It just seemed unstoppable. It only had a maximum speed of 196 miles, and an altitude of about 15,800 ft. During the war, it was mass produced. After the war many were sold and one was bought by Jacques Cousteau. Unfortunately that plane crashed on the Tagus River (rio Tajo) near Lisbon, Portugal, while making a landing. The crash claimed the life of Phillipe Cousteu, Jacques younger son.
As a child, my grandfather told me of a german flying boat, the DO-24. It was made by Dornier. Just like the Catalina, it was developed in the 1930's. It also had some nice lines. It also had 3 engines, which was fairly rare. It also had twin tail and its floats where 'water wings' adjacent to the body/hull. I don't find it surprising that the DO-24 and the Cat had similar configuration. Long thin body that also served as a hull and a high wing that held the engines. The 'water wings' served as a way to get in and out of the craft while in water. Unlike the Cat, the DO-24 did not have a landing gear for runway landings. It was strictly a water lander. My grandfather told me he served on one in the war as a flight engineer. He said that the 'water wings' also served as secondary fuel tanks, and that they prefer to use up the fuel in those before making a landing. I asked him if he ever saw combat. He said that his plane never fired a shot, but instead would rescue downed pilots. They even rescued British pilots and took them back to their lines. I found that hard to believe, but I had no reason to think he was lying about it. He also told me that before serving on the DO-24 he served on a DO-X and went on a mission to listen to radio signals just about 30 miles off the coast of New York. I assumed that refueling was done by ship. It certainly was a different world back then. There was a restored DO-24 called DO-24 ATT. It featured modern engines and added landing gear. It flies for demonstration and education. The DO-24 had a maximum speed of about 212 miles per hour and a max altitude of almost 20,000 ft. It was faster and flew higher than the Cat, and took more cargo. The german machines tended to be more powerful than the allied ones.
The PBY Catalina and the DO-24 were great aircrafts for their times. Today we have developed impressive airstrip technology where we can send a engineering crew to make one in hours from a jungle. We also have large aircraft carriers and helicopters. Land everywhere cargo task is mostly done by cargo planes like the C-130. So, all the tasks that these flying boats did are divided among several aircraft and some techniques. Even so, we can marvel at what these planes and others like them accomplished from the 1930's to the 1950's.
I love the slow rotor technology developed by Carter Aviation Technologies. It is a smart vertical takeoff and landing craft with long range. Hopefully it will find a good market in aviation. The engineering being this tech is pretty impressive. As cool as it is as it is, I love to imagine what technologies can do if they were configures or applied differently.
What if the Carter Copter had a different wing configuration? Actually I was thinking about a lifting body configuration. Now that may sound strange or even insane, but bear with me a minute. The wings on the Carter Copter are long and thin. They are not used to provide lift during takeoff and landings, the rotor does that. They are to provide lift during cruise at speed. A lifting body needs speed to provide lift. In fact it needed a lot of speed even to land. So it could be a good candidate for the Carter Copter.
Now, the engineering needed to fashion an appropriate lifting body for the Carter Copter has to be creative. The lifting body has to provide lift for the craft at cruise, stability for flight, and allow for enough down wash of air from the rotors for takeoff and landing. I imagine a rather thin one with a rounded nose and a bulbous dorsal. The benefit of a lifting body to the craft is that it would have less drag while in cruise increasing the lift to drag ratio. It should also provide a good volume inside the body for accommodate crew, passengers, and cargo. Could such a lifting body be designed? Would its performance be better than wings? Would it be stable enough? Would it really be worth it? These are the questions engineering would answer on paper. Some major aerodynamics would be utilized in such a project.
Let's take this tech to the next level. Could it be pushed to supersonic speeds? Lifting bodies can even do hypersonic speeds. The real question could the rotor be designed in such a way to handle such speeds. The rotor was redesigned by Carter Aviation Technologies just to crate the slow rotor tech. What design changes would you have to make to handle transonic speeds? Doesn't it get you thinking? You could end up with a supersonic aircraft that doesn't have to land or take off from pavement, let alone a runway.
Such musings are fun for me. You can take an existing technology and turn it into so much more. Of course, it's just musings. Reality has a tendency to shatter dreams. Proof is in the numbers and experiments though. Those can be just as fun.
Have you read Dr. Zubrin's article on VASIMR? WOW! Dr. Zubrin knows his stuff. Many scientists and engineers know their stuff. There is just a lot of controversy and opinions about how to get to Mars. Thank goodness that they are not trying to decide on a recipe for pumkin pie. They'd have to put on my tomb stone, 'Died waiting for pumking pie.' Yeah, Dr. Zubrin has some misgivings about VASIMR, but what is VASIMR and what are the other propulsion systems he's talking about?
Deep Space 1 - first spacecraft to use Ion Drive
VASIMR (Variable Specific Impulse Magnetoplasma Rocket) is taunted as a plasma propulsion system. It uses radio waves to turn matter into plasma then uses magnetic fields to accelerate the plasma out of the exhaust. If the energy is doing two things, you can see that the efficiency of the system is probably not good, just as Dr. Zubrin said. Sometimes projects need longer time than others to come to a good solution. If you look at the history of the internal combustion engine, you will see that it has a long list of epochs and people working on one thing or another that eventually became the internal combustion engine we so adore by revving our engines while standing still at a red light looking at one another as if we were a formula 1 race car driver while living things choke on the fumes. Despite Dr. Zubrin's desire to excuse VASIMR and politician's desire to promote it, it still may be key to a future and better propulsion system than we have today. Yes, we should've told old Robert Goddard to stop playing with those toy liquid fuel rockets, nothing would come of them. No, nothing; just taking men to the moon. That's all.
Ion drive is a propusion system that emits ions. It uses an inert gas and voltage differentials to accelerate the gas. The result is that it takes a long time to get to the destination, but its cheaper than large conventional chemical rockets to get up to speed. Deep Space 1 got to fly around the southern pole of the Sun and Smart-1 got to go from Earth orbit to Lunar orbit on ion thrusters. Dawn got to Vesta and then to Ceres. It could only accomplish visiting two space bodies with an on board main thruster such as the ion drive to escape the orbit of one and insert into the orbit of another. It's like scampering around the asteroid belt. I hope it finds its cheese.
Thermal nuclear propulsion system is one that emits matter heated by a thermal nuclear reactor. We're talking a rocket here. Well, the idea is that energy in the form of heat from a nuclear reactor can heat up a gas and produce really fast speeds for a spacecraft. That could be a potentially good propulsion system. OK, let's see. In the wiki it mentions thermal nuclear reactor and hydrogen in the first sentence. It also mentions that a core was made in 1955. I don't know what they were smoking in 1955, but it must have been good stuff. What do you tell the first guy that's going to fly this thing?
"Here you go buddy, just plant your seat right there and strap in. Concerns? Nah, we don't expect anything to go wrong. It will be a fun ride. Here, just sign on the dotted line right here. Small print? Don't let it concern you, it's just some legal mumbo jumbo and all. Have a safe trip."
Who in their right mind would fly this? I don't think the human psyche can dismiss images of a big explosion when talking about nuclear reactor and hydrogen together. Dr. Zubrin wants NASA to research this. I hope a working model would be indeed safe.
Let's talk about the big one, nuclear pulse propulsion studied under the name of Project Orion. Essentially, its thermal nuclear explosions detonated just behind a very thick pusher plate. Do this several times and the craft accelerates in pulse intervals. It's funny that the scientists were talking about making a farm on a spacecraft that uses this propulsion. The energy this thing can harness is enormous. It's the largest energy per weight that we know of. The scientists involved do agree that there were some issues with the system to be worked out. The basic idea works, and was tested on small scale with conventional explosives. Now, it's pulse propulsion. That means one minute your all fine and dandy and the next your splattered against the back bulkhead until the acceleration stops. Then it starts all over again. How uncomfortable does this seem? Can you imagine a cow handling this? You'll probably end up with sour milk. In spite of the challenges of this system, the scientists were optimistic about making a viable system.
Light Pulse propulsion is a modern idea that has some relation with nuclear pulse propulsion. The idea is that while in atmosphere, a laser can give a reflector with a particular shape power to heat up air and make it expand thus propelling the craft. The laser is shot form the ground. This is to propel a craft from the ground to orbit as a first stage. It's a compelling idea, because you have your power source on the ground and not as dead weight on the craft. If you use a dedicated nuclear power facility with a very large laser, then you can lift a lot of stuff and many craft to orbit reducing the cost of launch over time. I like this idea. I wonder if it can roast some marshmallows in flight. The in-flight meal should have s'mores in it.
Well, that's what Dr. Zubrin was talking about, and more. We get weird ideas about how to travel from point A to point B. Most don't work. We keep trying until we get it right. You can get your idea a try if you study Math and Science. Your going to have to learn to write and argue as well, because your going to get criticized. Are you up for the challenge?
[NOTE FROM THE AUTHOR: The humor in this post is and experiment. In no way was the intention to criticize. I'm sorry if it comes off that way. I'm keeping the post as is as a reminder of how poorly chosen humor can hurt.]
The Shuttle had wings to fly its way to a soft landing on a runway. So wings were used in the Earth's atmosphere to help spacecraft operate. What if rotary wings could do something similar? The first commercially successful rotary wing craft were De La Cierva's autogyros. The autogyro works on the principle of auto-rotation. Therefore, it can make safe unpowered landings. A helicopter works on the principle of powered rotors which allows it to take off vertically. A rocket lifts off vertically and its capsule lands with parachutes in a vertical fashion. So you see mixing these technologies together may not be so far fetched after all. Let's look at a couple of projects.
NASA's Roto-Capsule concept
NASA put out the news report entitled Engineers Test Rotor Landings for Capsules. Apparently the Roto-Capsule (I just made it up), uses auto-rotation like an autogyro does. They also want to figure out how to get the rotors to start spinning. In old and small autogyros, you hand start the rotor spin. Yep you have to use those mittens, and don't stand up too tall or you might get whacked by a blade. The larger and enclosed autogyros use a bendable drive train from the engine to the rotor hub. I suppose NASA could start the rotation of the Roto-Capsule's rotors with simple thrusters or even with an electric motor. I'm sure they can come up with better ideas than I can. They do have to figure out what the best solution is, what is the lowest weight for a system, how strong is it, and what are the operational costs to it. Looking at the picture, I can't help but wonder if this is an excuse to get scientific data form the engineers propeller beanies.
Another project was, if you can believe it, a rocket with rotors on the top. It was called Rotary Rocket. Apparently its rotors were also for landing. The concept was revolutionary for its time; late 1990's. It was touted as a single stage to orbit. It went as far as a demo vehicle that flew with powered helicopter rotors. There were aerodynamic problems with it, but an arial test vehicle was made and flown showing that rotors could lift the rocket. It was almost sad to see this project die, but I think they put too much in the concept. I mean, why would you want to use rotors to land a rocket? Wouldn't the rotors be useless weight for most of the flight? You can say that wings are too, and they are. Rockets would be less overhead weight as far as hardware because you need to rockets to launch as well as land. I suppose the argument is how much extra fuel your willing to take on a flight. That's where the weight trade off is. Rotary wing craft are what we have that closest behaves like a small space ships in sci-fi fiction in atmosphere; they land and take off vertically. I guess sometimes we can dream too big.
In my own muses, I thought if we can air launch a rocket to orbit with a plane, then why not with a rotary wing craft? The craft would have to be very large though. It would have to be custom made to lift vertically to altitude. It would have to be a separate vehicle from the rocket. I imagined it being large enough to fit the rocket in the middle of it and launch at altitude in a vertical attitude. The savings would come with launching from altitude in a vertical position. It does seem superfluous though. Stratolaunch is making the largest plane to launch a medium size rocket from altitude. The plane will probably need the biggest of runways. That's where my rotary wing craft could come in; in scaling up. I wouldn't need a runway, just a pad. That's less ground infrastructure than a plane. These are just muses though; ideas of runaway imaginations. Rarely does a dream come to life. I'm glad of that, cause I've had some nightmares.
So we looked at a couple of projects that involved rotary wings and space craft, and then one of my imaginations. That's what your going to get when you read my stuff. I just scrape things off the wall. Is it really a good idea to mix rotors and spacecraft? Maybe, but also maybe later. We still have a lot to learn about launching stuff into orbit on a shoestring budget.
I recently read an article that advocated a full retirement of NASA in favor of commercial space companies. The article can be found here. It was written by Omar Allam of the Daily Campus. While I support the commercial space effort, I don't advocate canceling NASA altogether. NASA has been in the space flight business for over fifty years. We need NASA for research and guidance. Let's look at NASA's past, present, and future.
Bell X-1
Before NASA was what it is today, it was NACA (National Advisory Committee for Aeronautics). It did research for the aviation industry. It figured out what was safe and what was not. NACA was open for both commercial and military aviation research. Its crown project was XS-1 or Bell X-1 which broke the sound barrier. NASA took over all NACA's assets in 1958. They still do research for aircraft of all sorts. Check out their aeronautics web page. They still have valuable research for aviation.
NASA has sent men to the moon and back to Earth. It has maintained a human spaceflight program since the early 1960s. It has operated some of the biggest and most unique spacecraft in human history. It has documented all that experience and research. Now, with a budding new space market for humans NASA has much to offer. How to make rockets, how to launch spacecraft, how to protect spacecraft, how people live in space, how to assemble space assets in orbit, and the list goes on and on. This stuff is invaluable to companies like SpaceX, Orbital Sciences, Boeing, and Sierra Nevada who are making spacecraft for humans and their stuff. Without NASA, these companies wouldn't have the opportunity to be successful in this current era.
Gemini Rendevous
NASA needs to stay as the prime space research institution for questions that have yet to be answered. How do you really mitigate bone loss in humans? What is the best way to engineer artificial gravity? What ways can cosmic radiation be reduced for acceptable levels for humans? How do you grow food in space? How to recycle vital resources such as air and water? What emergency procedures should there be in case of a rapid decompression? What alternate propulsion can we have? Question like these and many more I haven't thought of and many many more we are yet to ask are all areas where NASA research is beneficial. These questions are one to be asked by commercial companies as they increase there sphere of operations in space. NASA should be there to get them answers.
Understanding the roots of NASA and what it is currently doing, we can grasp its future role. I advocate a cooperative effort between commercial space companies and NASA. Anyway you look at it, it's a win win situation. Our past success in space is due to careful actions on the part of government space programs around the world. NASA is one of the premiere space programs in the world and one of the highest esteemed in aerospace research. It would be foolish to set it aside.
From time to time in the history of flight there has been some unusual designs. None are more unusual than round disc-like wings. If you google "round wing" or "disc wing" you get all kinds of images of planes in history with round wings. Funny thing is that some of these planes are popularily known and were done in the open. Others were secret projects, and their information is part of lore. Let's look at some of them.
McCormick-Romme Umbrella Plane
Among the earliest ones I found was the 1911 McCormick-Romme Umbrella Plane. The link goes to an obviously private site. Yet the plane is listed in the Wikipedia page entitled "List of aircraft". I find it fascinating that in 1911 people were coming up with all kinds of ideas for flight including a round wing. We're often told that flying machines followed birds in the way they fly. Have you ever seen a round wing bird? I suppose the frisbee had something to do with the thought pattern of the design of this plane. Throwing around a spinning cake pan is a fun toy, why not make it into a flying machine?
DiscRotor
Johnathan Edward Caldwell came up with some fascinating ideas for flight. One of them was a sort of autogyro with a disc on top. The disc had four rotors coming out of it. The idea was that the disc and rotor rotated and lifted the craft off the ground much like an autogyro. Then as the craft sped up, the rotor would stop and the disc would provide lift acting as an airfoil. Well, today this idea is being explored anew. The DARPA DiscRotor project is trying to make a VTOL aircraft with this disc and rotor combination.
In the 1930's and 1940's Germans were doing much technological research. Messerschmitt came up with the Me-600. This was a propeller airplane with the main wing in a disc shape. It had a tail with elevators and a vertical stabilizer. It seems this idea wouldn't go away. I did find some evidence that Russians have built small aircraft similar to the Me-600.
Ok, let's get back to baking. Instead of a flying cake pan, this next one was named after America's favorite breakfast. The V-173 Flying Pancake had two very large props which gave lots of power to the craft and solved the problem of airflow circulating around the sides of the wing form the bottom to the top and reducing lift. It demonstrated near vertical lift. The large propellers design showed merit enough to make its way into the tilt-rotor design.
There is a lore out there that the United States has or had bomber size aircraft with round wings. Some people have claimed to have seen them. Some computer generated pictures have been made of them. They look pretty cool. A round wing with a nice curve to it seems sexy. So these things supposed to have been responsible for UFO sightings in the continental Unites States.
There is a guy that came up with a unique design for an aircraft. The main wing and the elevators were merged into a round shape. It was an idea that seemed similar to some earlier designs, yet it had its own characteristics. He had it put through a wind tunnel and made an RC model of it. The design seemed airworthy. He was going to market it. I'm not finding any reference to it on the web. I did see an interview with the guy and a reporter. He came up with the idea around the 1990's. So people are still thinking about round wings even today.
So I detailed some designs of round wing aircraft. Sure, you can call them flying saucers. I like my saucers to hold my tea cup, and not fly me around. Its a design that somehow entered our psyche and it won't go away. Design ideas tend to feed on themselves. New people pick up the idea and try to run with it. They tend to have limited success until someone makes a breakthrough. Makes you wonder if we own ideas or do ideas own us.
Let's talk about the big one, nuclear pulse propulsion studied under the name of Project Orion. Essentially, its thermal nuclear explosions detonated just behind a very thick pusher plate. Do this several times and the craft accelerates in pulse intervals. It's funny that the scientists were talking about making a farm on a spacecraft that uses this propulsion. The energy this thing can harness is enormous. It's the largest energy per weight that we know of. The scientists involved do agree that there were some issues with the system to be worked out. The basic idea works, and was tested on small scale with conventional explosives. Now, it's pulse propulsion. That means one minute your all fine and dandy and the next your splattered against the back bulkhead until the acceleration stops. Then it starts all over again. How uncomfortable does this seem? Can you imagine a cow handling this? You'll probably end up with sour milk. In spite of the challenges of this system, the scientists were optimistic about making a viable system.
In the 1930's and 1940's Germans were doing much technological research. Messerschmitt came up with the Me-600. This was a propeller airplane with the main wing in a disc shape. It had a tail with elevators and a vertical stabilizer. It seems this idea wouldn't go away. I did find some evidence that Russians have built small aircraft similar to the Me-600. 
