full scale manned rocket glider

[OverTheTop]

Thanks for the background sg. Have you thought about trying paragliding? I have done a couple of solo flights of that and quite liked it. No motor of course. These days you can even get a small motor in a backpack for using with them. I am willing to bet that given a few years they might even end up electric maybe.

Anyway, you could always start sans-motor, and add that to your kit later on.

Lots of different ways to get in the air. Some are safer than others .

 

[dhbarr]

alright then here's some context: i wanted to build an ultralight plane, i quickly realized i'll never be able to afford a proper engine, i almost gave up on the whole thing, then i thought i could still try to do a non powered glider, i again realized it'd be too much of a hassle to launch such a thing, then i remembered about those homemade rockets and now i'm here asking for advice.

i'm not trying to reach mach 1 or go to space, i just need the boost to launch a glider from the top of a nearby hill then glide to the landing zone.
i'm doing this one way or another regardless of what anyone tells me so if you guys would give me some practical advice i'd have much higher chances of success

We are giving you nothing but practical advice by trying to help you understand that what you propose is both expensive and dangerous. The mass of the motor you propose would be substantially more than an adult human male.

Getting enough expertise and equipment in sugar motors would cost substantially more than renting some paraglider lessons. And that's before the cost of the actual components to make a flight article. Which would then kill you.

 

[some guy]

nah i don't like the idea of flying a parachute. i haven't mentioned it yet but the whole point of this project is to get off the ground with a device that was built entirely by me and at the same time prove it's possible to build a flying machine on a three figure budget. at the very least tell me your thoughts on the rocket motor i came up with: heat resistant cardboard tube for the casing, powdered pvc mixed with kno3 for the fuel, and a concrete plug with a hole for the nozzle. that's just the general idea that my tests will be based on. the first milestone is to blast a 5kg payload into the air. from there on it's just a matter of upscaling the whole thing

 

[tim cubbedge]

Whatever you do, be safe but you will get no help or guidance with your motor on this forum.

 

[BDB]

I just don’t think it’s possible—especially on a budget. Rockets that are powered by O-motors are usually built of aluminum or high-strength composites. They are very expensive, and there is lots of engineering that’s required to make sure the powerful motor doesn’t rip the fins off. The bigger the fins, the more they flutter (no matter what they are made of) and the more likely they will break off during flight. I don’t see how you could build a glider that strong and still be light enough to glide.

NASA and SpaceX have thrust-vectored liquid rocket motors ($$$$), so they can have slow, gentle liftoffs. Our motors, and sugar motors, are more like missiles. In order to fly straight, they must accelerate very quickly so there is enough air moving over their fins.

In order to have a stable flight, you would need to have a thrust to weight ratio of 5:1, meaning you will need to go from 0 to 5 G’s in the first second of the flight. So if you + your gear + the glider + the sugar motor weigh 500 lbs, you will need an initial thrust of 2500 lbs. And it will all need to withstand the forces of a violent liftoff. I don’t think a glider could be built that strong. You would surely need some advanced composites—there goes your budget.

I’m guessing you want to do something like “Jetman on the cheap.” Those guys jump out of a plane to avoid the difficult take-off that I just described.

I, too, want to build a flying machine that was 100% built by me on a budget and that I could easily build and store at my home. That’s why I’ve been looking into paragliding lately.

 

[JoeG]

If you are serious and not just trolling, my advice follows:

If you have to ask the question, "How big will the rocket need to be?" This is not a question that can be answered. It is dependent on many variables. It's like asking, "How high is the sky?"

If this is the main question on your mind please abandon the idea of this project.

 

[BDB]

If this is a troll, took the bait. “Some guy” are you serious or is this like the thread last week about the the team of 12 disciples trying to go to the moon with a fluorine engine and a kickstarter campaign?

 

[dhbarr]

nah i don't like the idea of flying a parachute. i haven't mentioned it yet but the whole point of this project is to get off the ground with a device that was built entirely by me and at the same time prove it's possible to build a flying machine on a three figure budget. at the very least tell me your thoughts on the rocket motor i came up with: heat resistant cardboard tube for the casing, powdered pvc mixed with kno3 for the fuel, and a concrete plug with a hole for the nozzle. that's just the general idea that my tests will be based on. the first milestone is to blast a 5kg payload into the air. from there on it's just a matter of upscaling the whole thing

The materials you propose to use will result in an enormous fireball. 3 figures might be enough to build a launch rail provided you are a HAM who knows how to weld.

Rocketry is an amazing sport with a fantastic safety record. Go fly some midpower.

 

[some guy]

fine i'll do it by myself. i thought the whole point of this forum is to share your knowledge and help each other out. i know it's dangerous but where would we get if Gagarin and Armstrong decided to abandon their missions because it was too dangerous? we wouldn't get anywhere. thank you for nothing you won't see me here again

 

[Ez2cDave]

i don't care about legality and safety protocols.

Hmm . . . It all came to a "screeching halt" at this point !

Dave F.

 

[Steve Shannon]

i don't care about legality and safety protocols. all i need to know is one simple thing: how big of a rocket would i need to generate that kind of thrust? just a simple kno3 sugar rocket without any fancy exotic chemical additives. my budget is very tight

Well, there’s the reason few people are lining up to provide you with answers. You’re unconcerned about safety or legality. For us to help you accomplish your goal would be irresponsible. It does nothing to advance science. None of the pioneers in rocketry were total idiots. They took the time to learn the sciences. Gagarin didn’t go to a forum and pop a question preceded by “I don’t care about safety or legality.” You burned the bridge before you got to it.

You are asking a question that requires a basic knowledge of rocketry. The answer is in your question. You asked how large of a rocket (I assume you mean motor) it would take to generate 1,000 lbs. of thrust for five seconds. Rocket motors are sized by total impulse, which is the product of average thrust (1,000 lbs. in your case) times burn time. (5 seconds in your case).
So, according to your request, you would need a motor with 5,000 pound-seconds of total impulse. There’s the answer to the question you posed in terms common to rocketry.
If you’re really asking for the mass of such a motor, you need to refer to a property of the propellant called Specific Impulse, which is found most easily by dividing the total impulse of a motor by the weight of the propellant. The units are “seconds”. So, a 2000 lb.-second motor that has 10 lbs. of propellant, would have a specific impulse of 200 seconds. That’s about the Specific impulse (abbreviation Isp) of APCP. Potassium nitrate and sorbitol (the type of “sugar motor” most frequently flown at organized launches) has a specific impulse of about 164 seconds. So, working backwards, 5,000 lb. sec./164 sec. = about 30 lbs. of propellant.
Frankly, your initial calculations seem very suspect to me. You don’t seem to realize what 1,000 lbs. thrust would do to you or your glider, but it would be frightening to see.
And by the way, that motor that’s capable of generating 1,000 lbs. of thrust for 5 seconds, is capable of generating 10,000 lbs. of thrust for half a second. That’s why you have to understand what you’re doing.

 

[some guy]

thanks, Steve. your answer was exactly what i was looking for.

well, i guess i'll be leaving now. i don't feel very welcome here and you guys would probably ban me from here if i asked for advice on other stuff i have planned.

but keep having fun with your toy rockets while i at least try to do something bigger that nobody else would dare to attempt

 

[Zeus-cat]

Doing things that are dangerous will never be welcome here. I seriously hope this was all some sort of silly joke.

By the way, launching 5kgs of stuff into the air puts you in high power rocketry category. You need FAA clearance to launch a rocket this size even if it only goes 10 feet in the air. You also need an FAA approved launch site. But then again, you already said you don't care about legality or safety so I am probably wasting my time typing this.

And we do have fun with our toy rockets. And we live to launch another day after we fly them.

 

[solid_fuel]

I am going to go out on a limb and speculate that an as you say 'proper engine' will be cheaper than a rocket motor, also there is the reusability factor.

 

[Andrew_ASC]

Our “toy rockets” use physics and fundementals of engineering to operate safely. A “toy rocket” as you call Amateur high power rocketry landed me a two minute call to NASA hr because it was a national engineering competition for multistage rocketry as a fresh college engineering graduate. You could learn how to size a small parachute for a “toy” model first to save your own a** when you save up for your big project. You will not be able to do aviation on a budget safely or legally. Let me kindly inform you airspace incursions are radar tracked and investigated by the FBI with FAA radar data to grill you in court should you bust airspace. It’s a national airspace transportation system. Selfish pranks and suicidal flying stunts are not welcome. I had to put my dreams of flying as a licensed pilot on hold for budget reasons with 45 hours pic time in cessnas to finish college. You jeopardize OTHERS safety with a stunt like this if you do not follow rules. Flying is a privilege not a right. If you can’t understand this you clearly do not have the mental capacity to operate a flying machine let alone design one safely. I’m done here.

 

[solid_fuel]

Gagarin and Armstrong

two guys who had at least one hundred more dollars in their budget than you.

 

[jlabrasca]

well, i guess i'll be leaving now. i don't feel very welcome here and you guys would probably ban me from here if i asked for advice on other stuff i have planned.

but keep having fun with your toy rockets while i at least try to do something bigger that nobody else would dare to attempt

Well now that he's gone, we can resume our discussion of rocket-candy jet packs!

I was especially impressed by the OP's attempt to compel someone to assist in this folly by taking himself hostage:

...
i'm doing this one way or another regardless of what anyone tells me so if you guys would give me some practical advice i'd have much higher chances of success

Seriously, is there a document someplace that explains what happened in amateur rocketry after the September 11 attacks? I think it would be useful to point folks like "some guy" to that history before trying to explain that rocket science is, in fact, rocket science.

Maybe part of a FAQ?

Q: Can you tell me how to build a manned rocket/a GPS guided surface-to-surface missile/a full scale replica of an ME163 powered by a black powder motor...

A: <sigh. Please stop looking "King of Random" videos and read a book.> What you are proposing is illegal and/or very dangerous and/or considerably more difficult than you appear to understand. While we admire your creativity and enthusiasm, it would be unethical to help you achieve your stated goal. We also worry that it would cast our hobby in a negative light if you, or anyone else, were to be injured in an attempt to realize that goal. We can, however, suggest some resources where you can learn more about how rockets work...

 

[Cnorm]

thanks, Steve. your answer was exactly what i was looking for.

well, i guess i'll be leaving now. i don't feel very welcome here and you guys would probably ban me from here if i asked for advice on other stuff i have planned.

but keep having fun with your toy rockets while i at least try to do something bigger that nobody else would dare to attempt

This isn't the airport. You don't need to announce your departure. Just go.

 

[OverTheTop]

nah i don't like the idea of flying a parachute. i haven't mentioned it yet but the whole point of this project is to get off the ground with a device that was built entirely by me and at the same time prove it's possible to build a flying machine on a three figure budget. at the very least tell me your thoughts on the rocket motor i came up with: heat resistant cardboard tube for the casing, powdered pvc mixed with kno3 for the fuel, and a concrete plug with a hole for the nozzle. that's just the general idea that my tests will be based on. the first milestone is to blast a 5kg payload into the air. from there on it's just a matter of upscaling the whole thing

Three-digit budgets are not going to be realistic in many ways unfortunately. Stuff adds up quickly, even doing it on the cheap.

I can't comment on DIY motors as I have no knowledge or experience in that area. I barely have enough time for the rocketry that I do manage to get to.

Keep in mind that things scale differently due to physics sometimes.

 

[Crawf56]

Something to be aware of.

To get chemicals in the QUANTITIES you need, it is very likely you may generate "interest" from groups such as the FBI and Homeland Security.

Rocket thrust is essentially a semi-controlled explosion. So, you have to have something that explodes. Whether it's fertilizer or sugar, be aware that the current purchasing system in the USA has built-in monitors for quantities of items of interest.

 

[tim cubbedge]

Just so you know, some guy is posting from Europe.

 

[Crawf56]

The funny part of all this is that the "Airplane under $1,000" has already been done...…...in the world of RC aircraft.

Using skills learned from constructing RC model airplanes, a dude designed a small, manned aircraft using two RC airplane engines.

https://en.wikipedia.org/wiki/Colomban_Cri-cri

 

[ksaves2]

alright then here's some context: i wanted to build an ultralight plane, i quickly realized i'll never be able to afford a proper engine, i almost gave up on the whole thing, then i thought i could still try to do a non powered glider, i again realized it'd be too much of a hassle to launch such a thing, then i remembered about those homemade rockets and now i'm here asking for advice.

i'm not trying to reach mach 1 or go to space, i just need the boost to launch a glider from the top of a nearby hill then glide to the landing zone.
i'm doing this one way or another regardless of what anyone tells me so if you guys would give me some practical advice i'd have much higher chances of success

Save your money, learn to fly properly with an instructor and build (if you must) an honest to God internal combustion motor glider. You'll improve your chances of survival immensely if you stick with a
proven product. Look up the EAA. Trying to do it on the cheap will get you to an early death. Better take your savings to invest in a pre-paid cremation/funeral if you insist.
I doubt you will get any advice from anyone here because what you are trying to do is incredibly hard, most of us here don't know how to do it and the ones who know and have an idea
also realize it's a daunting task. They would feel guilty facilitating your early death or severe injury. You're on your own here and I suggest you let this thread die. AKS Q.E.D.

 

[Ez2cDave]

i'm not trying to reach mach 1 or go to space, i just need the boost to launch a glider from the top of a nearby hill then glide to the landing zone.

Have you considered a giant "Hi-Start" ?

Dave F.

 

[Steve Shannon]

Rocket thrust is essentially a semi-controlled explosion. So, you have to have something that explodes. Whether it's fertilizer or sugar, be aware that the current purchasing system in the USA has built-in monitors for quantities of items of interest.

This is a common misconception. Rocket thrust is not a “semi-controlled explosion” and although it took a nine year lawsuit, we were able to prove that APCP is not an explosive. Please don’t fuel (pun intended) this misinformation.
However, you are absolutely correct that fertilizer purchases are closely scrutinized because of the potential for misuse.

 

[jlabrasca]

Have you considered a giant "Hi-Start" ?

Dave F.

I wonder if BATF would be alerted if you order 1000 meters of surgical tubing? Sure, you say you want to launch your $900 glider, but you could be building the world's largest Wrist Rocket. Dennis the Menace-to-Society.

This is a common misconception. Rocket thrust is not a “semi-controlled explosion” and although it took a nine year lawsuit, we were able to prove that APCP is not an explosive. Please don’t fuel (pun intended) this misinformation.
However, you are absolutely correct that fertilizer purchases are closely scrutinized because of the potential for misuse.

Good point. However, what the OP was proposing with "one of those sugar rockets" that was also a "powdered PVC"/KNO3 (?) rocket, constructed from concrete and "heat resistant cardboard" does seem a likely recipe for an uncontrolled explosion.

 

[ksaves2]

Imagine sitting in front of that. I especially enjoyed the flaming laptop of death. I'm not criticizing the SS to space as those folks are trying to honestly make that goal without putting anyone's life in jeopardy. Kurt

 

[Ben Martin]

This thread

 

[les]

so if you guys would give me some practical advice i'd have much higher chances of success

The practical advice has been given - don't do it

No matter what, it is not going to be cheap. And no one has been talking about having enough power to go to space or break mach.
You stated you needed 1000 pounds of thrust for at least 5 seconds. The O3400 presented earlier does not quite meet your requirements.
Motor plus casing is 4" diameter by about 60" long and will weigh somewhere around 75 pounds. A sugar motor will be bigger and heavier - does this impact your airframe?

Meanwhile, to use such a motor does require an L3 certification - that process requires the L1 and L2 first - even on the cheap probably in the $2000 range.
We have a restricted area on this forum for motor making - you need to have your L2 certification and be a US citizen to gain access.

Bottom line - you are not going to get help here for what you are trying to do.....

 

[Ez2cDave]

Too bad Wan Hu isn't still around . . .

Dave F.