Supersonic Model Rockets

[90Graff]

Why do brits love rockets? all the videos are brits!

[samosammo123]

0:23 is it me or did that thing explode?

[Calvertfilm]

@samosammo123 It flew - what you see getting blasted to the side was the ignitor.

[samosammo123]

@Calvertfilm

oh ok, ty

[Calvertfilm]

@satweavers It depends what height it is when going supersoinc. It accels at about 100g, so it wouldn't be very high.

[carmium]

An acquaintance who's into this sort of thing (Dad owns a hobby shop) said he watched a friend's rocket that was specifically designed to break the sound barrier. To his surprise, it indeed made a "Whap-whap-whap" sound, as he put it, at peak speed. Shouldn't these rockets be doing the same, or is there a reason they don't?

[Calvertfilm]

@carmium The Space shuttle makes a double bang. A whip crack only makes one. It depends on the shape and size of the object. 

[carmium]

@Calvertfilm Ah! I didn't here anything on the vid, so I wondered.

[Calvertfilm]

@carmium As a matter of interest was your friends rocket the same size as these - 20 inches long, or much bigger?

[carmium]

@Calvertfilm First, I thought I might mention I DO know the difference between "here" and "hear." I was tired, I suppose.

I never saw the rocket, although, if I remember correctly, he said it was three-stage. That's about all I recall.

[Calvertfilm]

@carmium That seems pretty big.

[carmium]

@Calvertfilm The multi-stage rockets I've seen have short, finned booster stages not much taller than the motor. I presume this friend-of-a-friend's rocket was similar and not that big, since he launched it out of a city park!

[kobasica]

thats nowhere near supersonic

[Calvertfilm]

@drummer20011 Cool. If you ever put a C motor in it, it will go about twice as high!

[Calvertfilm]

@drummer20011 Yes. This was one of my first rockets and I lost the first as most people do. I put a 'C' motor in it and it drifted away, never to be seen again. So I would suggest a couple of things. First flight do with a small 'A' motor, then a 'B' next to get an idea of how high this thing can go. Also make sure you cut a hole in the middle of the parachute (spill hole) as this will help you recover it quicker. Don't launch in a wind. It is a robust little rocket. Have fun!

[Calvertfilm]

@drummer20011 Yeah, always. They went to about 2,500 ft, so not too high. They were built for speed, fast acceleration, not altitude. The streamers were about 2 metres long, and they took about 40 secs to decend (so going quite quickly on a streamer). This helped get them back near the launch site.

[Calvertfilm]

@drummer20011 Yeah. Did 19 flights and got them all. The first five broke up, as did one of the later ones. Those wings have got to be perfectly in line or it spins violently. Also the first five flight were perfecting the build strength and (low) weight.

[Calvertfilm]

@THECHEERIOSRINOS Rocket was intact, so I think that was the clips attached to the ignitor.

[hottieprowelder]

bip bip cherio

[Calvertfilm]

@hottieprowelder Tally-ho!

[galdorv]

Wow they are really moving! Its hard to believe that those tiny rockets have so much power!

[Calvertfilm]

@galdorv I tell you, the speed makes me get nervous each time I launched one. Mind you these are probably safer than an underpowered rocket. Even when these break up in flight they still go upwards and do it safely up high. That usually happens when I haven't quite got a wing on perfectly straight and it sprials violently.

[TheCasualTim]

please put an onboard camera onboard next time

[Calvertfilm]

@TheCasualTim These small rockets wouldn't be powerful enough to then go supersonic. They only weighed a few grams.

[sonicfan1234100]

omg how did u get that rocket can i bye it from you plz ?

[Calvertfilm]

It was a converted Estes kit. In this case a Thundersteak but it could have been anything similar with a 24mm tube.

It has a few mods: plastic wings, glue used was epoxy, tape around the top of the body tube for strength to hold the nose. Epoxy glue around the engine mount. Streamer recovery.

It's not for sale I'm afraid.

[L00NGB00W]

Ammonium Perchloride Hmmm?

Perhaps this will be easier to find than potassium nitrate.

I used to buy saltpeter at the drugstore... Can't find it anymore.... Damn 911...

[pkr40]

Most of my rockets you can hear the crack. But it doesn't mean that mine went supersonic.

[Calvertfilm]

This was a different sort of crack for these 19 flights compared to the other 700 or so flights I've done.

[pkr40]

cool rockets but like the person below said they don't go supersonic. I have rocket sim,wasp and a few other programs and I would like to know how you did. either way the rockets were cool

[Calvertfilm]

Well we were there, and we heard the supersonic crack for 19 flights. The video doesn't pick that up so well but it was happening. Also you don't have all the rocket specs to make an accurate simulation. My sim said 1,000 to 1,500mph depending on the desings I used. Speed of sound at sea level is 760mph. Also I had a few respected rocketeers watch them go, and we were all left in no doubt they were supersonic.

[ZenonDorinPower]

yes it's very cool,the acceleration and speed is awesome but it's not supersonic...it's impossible because even the bullet travels with a speed smaller than the sound's one.OK i have a question-did you use potassium chlorate instead potassium nitrate?

[Calvertfilm]

Some bullets can travel at twice the speed of sound. I used Ammonium Perchlorate motors - Areotech ones.

[indyschmidt]

Um, actually bullets are quite capable of breaking and even doubling the sound barrier speed. It depends on the type of bullet and the type of gun. When you consider that most missiles travel at speeds well in excess of the sound barrier for many miles, it is not out of the realm of possibility for a simple model rocket to break the barrier. All you need is stability and a lot of power. There's no reason you couldn't do this with a small-scale model.

[Calvertfilm]

Yeah Concorde used to fly at Mach 2 - typical bullet speed.

[ZenonDorinPower]

yea yea i was thinking it is needed a much bigger distance to reach the sound barrier,not just a few meters(because after the start the rockets don't seem to accelerate anymore,here's the bang).Concorde needs some minutes and a long distance to brake the barrier

[salleens7]

The ammunition fired by our soldirs in m16's m4's etc. are supersonic..

[Calvertfilm]

True. Most bullets are. End of a whip too (that's what makes the crack). And the tips of a helicopters rotors.

[Rcoketace15]

Are these rockets moving at supersonic speeds because you used a E motor? If it do you think it would work the same with a rocket that is 3ft and 4in tall or are the rockets short so there is less cofficent drag and that is why it travel at that speed.

[Calvertfilm]

Using computer software, I realised that an E motor had just enough power for this weight and size of rocket. But the weight is critical. Even metal wings tipped it over, so I used hard plastic. They were minimum diameter rockets (the size of the motor), and I did everything I could to minimise drag (three wings instead of four etc). The profile of the wings was a supersonic diamond. The rocket only went supersonic for a moment. With bigger rockets you'd need bigger motors. I was on the limit.

[Rcoketace15]

What was the computer program called and how can I get it?

[Calvertfilm]

Google 'Alti Calc'.

[Calvertfilm]

These rockets are 2.5 feet long typically, although I did make some Zinger conversions which are about a foot.

[gloria3762]

where can i get these?

[Calvertfilm]

Internet search 'Aerotech Motors' for your nearest motor stockist.

The kit was a modified Estes kit. I used plastic wings expoy glued on, and tape around the top of the body tube to avoid collapse of the nose into it. Motor mount used epoxy too. Don't use balsa wings as they get ripped off. Internet search 'Estes'.

[gloria3762]

where do you get these engines? or if you can modify them how do you do so?

[Calvertfilm]

I was using Aerotech Ammonium Perchlorate motors, E rating, single use, not reloads. E-25s I think with a high impulse. Unmodified - I never alter my motors for safety reasons.

Best internet search 'Aerotech Motors' for your nearest stockist. Mind you I'm not sure they still stock the above motor rating.

[drugsandsolvents]

yo man please fire one of these at a TV or old car (or just at the ground) or something Imagine what it would do to it at 1000 mph daaaamn. Ur vids rule ! peace out :D

[Calvertfilm]

Thanks dude but I get shakey just launching these normally. If they were to go wrong, they would go wrong in a bad way. I did 19 of these launches I think, and now I'm out of motors. These launches happened around ten years ago now :-(

[Sean6196]

hey mate, i'm a second year aerospace engineering student, and i was building rockets as part of the university rocketry club; i was just wondering what would you say to be the best way and position to house a gps transponder system.

[Calvertfilm]

Well, I have no experience of this myself, but I would suggest the nose cone. A rocket benefits from weight at the front (like a dart). That is if you have the room (depends on the size of your rocket and GPS system). It would also be protected from the backfire gases.

[cferg47]

cool!

[5813791]

good idea but i like my parachute because its not a big field its concreate and some grass and the fins are made from balsa wood

[Calvertfilm]

Good point. For that surface a chute is fine.

[5813791]

ya id like to stage it but i got one of the smaller rockets. when i get a 2 stage ill do staging but 1 works for now. i found cutting a hole in the top of the parachute helped me get it back. it didnt drift and the fins are still on lol.

[Calvertfilm]

Glad you are having fun with it. The spill hole aids the stability of the chute as well as helping to get the rocket back quicker. It also packs smaller into the tube, so less likely to get stuck. If it is a light/small Estes rocket I normally use streamers made from kite tails.

[5813791]

i launched my rocket today and got it up to 1500 ft. and i found it lol

[Calvertfilm]

Cool. Now try staging it? :-)

[5813791]

u find ur rocket??

[Calvertfilm]

Sure did - watch to the end of the video.

[shdavis745]

It is also hard to hear any kind of noise from the rocket breaking the sound barrier, because it is traveling upwards with the rocket, and the noise from from the motor burning would likely cover up any hint of a sonic boom.

[38supercomp]

That is not supersonic. There is no sonic boom from it breaking the speed of sound.

[Calvertfilm]

With something this small it makes a crack. Much like a whip crack. The end of a whip is also supersonic but doesn't make a boom either as it is too small.

[drsheikhjunior]

Thats supersonic,it looks like the rocket took off faster than the sound,try to listen clearly.

[jknox71]

good video, looks like fun.

[boondocksaintpoop]

I have a few questions, where did you buy your motors and what is the largest motr you can get like a "G" motor

[bto4]

wicked cool

[astronut123086]

HOW DID YOU MODIFY THOSE? Those are absolutely insane.

[Calvertfilm]

Thanks. The wings were made from plastic, not balsa, and expoy glued to the body. Balsa would rip off and ali metal was too heavy. They had bevelled leading and trailing edges. The motor mounts were expoy glued too. The top of the card tube had tape wrapped around it to stop the nose collapsing into the tube. Recovery device was a small streamer. Motors were Aerotech E15 and E25 motors I think. Beyond that I find it hard to remember now - it was a few years ago.

[JDIEZLL]

i have a bigdaddy rocket w/ E9-6 engine but it can't go faster than urs...KOOL

[PrinceBR373]

Cool video I really like it

[Calvertfilm]

Thanks!

[PrinceBR373]

you're welcum