Afterthoughts
I first decided to write this paper late in 1995 because it looked like privately-funded manned spaceflight was never going to happen. There has been a lot of talk about the subject with various space development societies promoting their ideas. Ideas, dinners and galas will not put someone in space -- someone has to act.
I first learned of the X-Prize shortly after I sent this paper to various individuals and small rocket companies. There are now 15 officially registered competitors for the X-Prize
I met one aerospace engineer who was interested in working on the manned rocket named Joe. Joe came up with a design, introduced me to hybrid rocket motors, and became my mentor. He would design rocket motors on his computer, then go to his garage and cut them out with lathes, drills, saws, and elbow grease. I felt like Luke Skywalker being taught by Obi-Wan Joe the rocket master. I have yet to meet anyone who held the fire and passion from that better vanished time that everyone calls the "glory days" of manned spaceflight. To put it simply Joe is my hero.
Nineteen ninety-seven looked to be Joe’s and Glen’s best year yet. The design of the craft was nearing completion, the skeleton structure was under construction, Joe had the materials to build a thousand-pound thrust motor and had already fired a 100-pound test motor, but there are more things in life more dangerous than experimental manned rockets; Joe was involved in a tragic car wreck during the Christmas holidays. A 3000-foot manned rocket launch has been trivialized by some people as a cheap stunt, but no one yet has accomplished it. The Germans tried in 1933 to launch a man to 3000 feet and their project ended in chaos. Evel Knieval failed to fly over the Snake River Canyon, and others have started manned projects and lost interest.
If a privately funded 3000-foot manned rocket launch was such a cheap stunt, it would have been accomplished by now. What N.A.S.A. and the military have done is great, but they will never let us buy tickets to ride their rockets, but we will pay for them with our taxes.
The X-prize is mankind’s greatest hope to reach the stars. When I first heard about it, it humbled me. I was glad that the future of civilians in space now had a bright new shinning star of hope, but I also felt a little dejected because it was now really hard to sell a low-altitude manned rocket built in a garage and flown by a novice skydiver. But Joe cheered me up and was determined to drive forward with the project hoping to fly our rocket before the aerospace company heavyweights could get their spaceships off the chalkboard. Joe did not believe in leaving anything to chance or fate.
This is the story of the little rocket that could have -- and still might.
The Barnstorming
Air Show Rocket
By Glen May
Introduction
The purpose of this short paper is to promote a manned rocket flight to 3000 feet, organized and constructed by rocket experimenters. The year 2000 is rapidly approaching and no privately sponsored manned rocket has yet to rumble off the launchpad. Evel Knieval made one valiant attempt to jump the Snake River Canyon in the 1970’s, but the parachute deployed before the " Sky Cycle" left the ramp. Evel survived and he and the engineer Bob Truax made a considerable amount of money. The technology exists to accomplish a 3000 foot manned launch; all that is needed now is the vision, funding, purpose, teamwork, and a willing rocket pilot to accomplish this daring deed.
THE VISION
The manned rocket will be propelled by a solid propellant engine and recovered by parachute. After the parachute opens, the rocket pilot will open the capsule section of the rocket, bailout, freefall for 5 seconds, and open his own parachute.
A engine burn time of about 7 seconds and a speed of 280 mph will be needed to attain an altitude of 3000 feet. Complete deployment of the rocket main parachute should be completed by 2600 feet, bailout by 2300 feet, and the pilot’s parachute deployed by 2000 feet.
The fueled rocket should weigh no more than 1500 pounds and be capable of lifting a 250 pound person. Acceleration should not exceed 5 g’s ( 4 G’s actual acceleration + 1 G Earth). The total liftoff weight should not exceed 1750 pounds. The engine or engines will need to develop 5500 pounds of thrust at liftoff.
The rocket will have the following characteristics:
Rocket Flight Profile:
The Funding
Funding is probably the hardest part of the project to conceptualize. This paper is going out to many rocket and experimental aircraft enthusiasts, and I hope generates many ideas. Some that I’ve thought of are pretty conventional, but some may be far-fetched.
I anticipate this project to be relatively inexpensive. We are not going to the moon, just to 3000 feet with all the fire, smoke, and thunder that NASA once shot for the moon. All that is needed is a rocket that will not fall apart at 300 mph, an engine that develops 5500 pounds of thrust reliably for 7 seconds, a surplus Army cargo parachute, a comfortable flight seat, a used sport parachute rig, the courage to believe in our work, and a willing pilot to strap himself inside a flame spitting missile.
The Purpose
The reason we should launch a manned rocket is simple we can do it. Other reasons:
The Team
In the beginning, ideas for the construction and design of the rocket should be freely shared between enthusiasts. The Internet, telephone, and the postman should be our couriers.
All involved should elect officials like president, vice president, and treasurer, etc. to organize the efforts. Action steps will be voted on just like any organization.
Various talents will be needed, some of them are:
The Willing Rocket Pilot
Well, if you haven’t already guessed, I’m one volunteer. I’m 34, 185 pounds, 5’ 11’’, and in good health. I am not just a thrill seeker; I just have dreams that will not die. I know I can survive this and I believe and trust in parachutes. I have made over 300 parachute jumps, mostly sport, and some in the Infantry of the 82nd Airborne Division . I do believe this project is potentially dangerous, but it is a necessary rite of passage. Manned rocket flight is the wide open highway we must travel for the growth of privately funded experimental rocketry.
Why 3000 Feet?
1. Low cost
2. Lowest altitude that a bailout can reliably and safely be
accomplished
3. Low speed makes for a safer flight
4. To give the crowd a good show since the whole flight will be
clearly visible
5. Not much is needed to set a world record in this
arena
Development Outline
Safety
Every conceivable danger must be openly discussed. Some of my own concerns are:
Problems
The parachute for the rocket will be stowed behind the capsule section. The fins could snag the pilot chute and prevent parachute deployment. I would recommend a ballistic parachute deployment at a 90 degree angle to the rocket so that the pilot chute will clear the fins.
The fact that the rocket is fat at the top and skinny in the main body makes it difficult to use a launch lug like a conventional model rocket would use. Some method of keeping the rocket stable during its first few moments of flight needs to be conceived.
A possible solution to the rocket parachute deployment would be to use a parachute with a long bridle line . The parachute shroud lines would not start unstowing until the bridle line is fully stretched out and the parachute and its deployment bag are behind the fins of the rocket. This should prevent an entanglement.
Target Specifications
Engine burn time 7 seconds + /- 1 second
Powered flight distance 1600 feet + /- 200 feet
Rocket speed at
engine burnout 280 mph +/- 20 mph
Coast distance 1400 feet + /- 200 feet
Peak altitude 3000 feet + /- 250 feet
Maximum acceleration 5 G’s
( Earth plus rocket engine)
Loaded rocket weight 1750 lb.
with pilot
Minimum liftoff thrust 5500 lb.
Estimated flight time of
rocket before parachute
deployment 20 seconds
Estimated total time in air 3 minutes
Maximum pilot weight
with parachute 250 lb.
Stabilization method fin
Engine solid propellant
Ignition method electrical
Epilogue
Allow your imagination to soar. You walk towards the launch tower with flight suit and helmet on. Pause a minute and look at the strange rocket that will carry you into the blue sky. Climb into the capsule, strap yourself in, and say a quick prayer before the countdown begins. As the countdown ends, hear the sound of rolling thunder when the solid fuel ignites and you are pushed into your seat. The roar of the engine becomes deafening as the fiery rocket defies the earth and goes whizzing through the sky. The crushing G forces are replaced with a euphoric sense of weightlessness as the engine spits its last flame. The ship coasts for a few precious moments. You are relieved when you feel the jolt from the main parachute opening. It is time to eject the canopy, bail out, give a good "Airborne" hard arch and pull the ripcord. The beautiful red, white, and blue parachute opens. Spiral down and land in front of the clapping crowd. You and the team are steely-eyed missilemen.
Dedications
For Krafft Ehricke and Max Valier- The boldest of the bold
To Phillip for keeping the dream
To Joe for everything
And the crew of Apollo 1, Challenger, and all the cosmonauts, engineers, and workers who lost there lives aiming for the stars
Have Parachute
Need Rocket
UPDATE: This paper was first mailed on Jan 27 1996. I have had several responses to this paper. I have been advised that a liquid fueled engine or a hybrid would be a better choice for this task..
I now believe solid propellant engines should not be used .
A hybrid engine would be safest.
The rocket altitude goal has been moved to 4000 feet to give a extra margin of safety.
This paper has been altered from the original
Copy at will
Correspondence:
Glen May
118 Tamin Cove
Byhalia, Mississippi 38611
Phone (662) 893 0240
02/05/96
The Counter Proposal
Dear Glen:
My name is Joe, I have a degree in Aerospace Engineering with a background in propulsion. I am writing in response to your "Manned Model Rocket Project" proposal which you submitted to my company RPS. I must admit that when I first opened your package and read the title I was highly skeptical. As I read your proposal however, and did some number crunching with your various specifications, I came to the conclusion that the task probably could be accomplished for both reasonable cost and risk.
If you will bear with me I do have some comments and suggestions for you.
My first suggestion is you change the name of the project. I believe that you may have trouble convincing potential (non technical) corporate sponsors that you want to launch yourself in a large model rocket! I also feel that the term "Model Rocket" does not reflect the serious challenges that this project will pose.
I’ve enclosed some copies of photos that I took at Edwards AFB in 1979 when Budweiser sponsored a rocket powered car to break the sound barrier. I believe if they were able to obtain corporate sponsorship so should you.
While your proposal to use a solid rocket to boost a mortar type vehicle is certainly feasible and probably could be done safely, I have drafted a proposal that I think would have some advantages.
Propulsion
Although solid propellant rockets are certainly easy to use, just light the candle and go so to speak they are not easy to design and build.
Some of the factors that must be considered are....
0 What type of thrust time curve is desired?
progressive?
regressive?
neutral?
0 The trust time curve will determine the propellant grain geometry.
0 The propellant must then be mixed and cast into the motor casing while molding the proper grain geometry and avoiding the formation of void spaces.
0 Ideally the propellant should be degassed in a partial vacuum, and curved in a temperature controlled oven.
0 This all must be done with approximately 200 pounds of highly flammable propellant.
0 of course the one major operational disadvantage of solids are their lack of controllability, once lit there is no stopping them!
For the last year I have been developing hybrid propulsion systems for high powered rockets and have been very pleased with the results. The fuel grain (HTPB) is very easy to cast. With the use of plasticizers it can be poured easily like any liquid. A simple port burning fuel grain exhibits neutral burn characteristics. The fuel is virtually inert under normal conditions and poses no combustion hazard. the oxidizer, nitrous oxide, similarly poses no hazard under normal conditions and requires no preparation. The Nitrous oxide is simple injected into the combustion chamber and the motor is ignited! One of the other features I like about this system is its controllability. The motor can be started and stopped at will, a handy feature if your were to find yourself veering way off course. My test stand is computer controlled and I have consecutively started and stopped a motor up to three times. The motors can be throttled to some degree, and with some work I believe they could be throttled over a fairly wide range. (Not suggesting we necessarily develop throttleable motors for your project). Another attractive feature of the hybrid system is that it is reusable, and can be designed to be expandable, in the event a higher total impulse were desired at a late date!
I’ve enclosed sketches of two preliminary designs of hybrid motors for use in your project. The 5500 LB thrust motor design to be used with your mortar type airframe, and the 1500 LB thrust motor to be used in an airframe I propose and will discuss below.
Airframe
I assume that the reason you specified the large diameter crew compartment and small diameter afterbody is to reduce the chance of striking the vehicleif you had to bail out while still in forward flight during an emergency situation. (e.g. if the parachute failed to deploy properly). One problem you may encounter in such a situation are the recirculation zones that exist behind bluff bodies like the crew compartment. These recirculation zones would tend to pull you in, putting you on a possible collision course with the fins or afterbody.
One way to avoid this hazard would be to build a vehicle that had no fins or afterbody. I propose building a conical shaped vehicle that is inherently aerodynamically stable and requires no fins. The vehicle would have an open canopy, and in the event of an emergency egress situation you would simple pull yourself up onto the head rest and lean backwards to let the slip stream slide you off the back of the vehicle like a sliding board.
Another advantage of the conical shaped vehicle is it structural stability. The load from the smaller forward sections are distributed over the larger areas of the sections immediately behind.
A conical shaped vehicle would also be very easy to build since it is composed entirely of straight lines. With the low acceleration involved (3 to 4 Gs) it could be constructed of anything from aircraft grade lumber to composite materials.
Please keep in mind that all calculations and proposals are preliminary and are not etched in stone. For example upon further examination it may be decided that a hydrogen peroxide solution or liquid oxygen may be preferred to nitrous oxide. Or perhaps a closed canopy may be desired over an open canopy. There is a lot of work ahead to be done! Please review this, and let me know what you think.
Good Luck
Sincerely,
Joe
Ram Propulsion Systems