single chute recovery at high speed

[John4645]

So I am reading my new copy of Modern Highpower Rocketry and duel deployment and I also was reading the post on ballistic approach recovery in the support and recovery forum and since I do not have any experience with High power or high altitude I have to ask this question, Is it not possible or correct, legal or ethical to launch a rocket to lets say 5000' let it fall to 100' or 800' and then just have one chute open and recover? Now I understand that the rocket will be traveling at high speed, I guess 125mph or so. Anyhow just looking for an education on this. Some answers. Can you not build a rocket or recovery system strong enough? or is it just to unsafe? Thanks.

John

 

[Yoehahn]

I do it most of the time. You just use dual deploy and leave out the drogue shoot which is what 90% of people do here on the east coast. It's only dangerous if it doesn't separate

 

[Area66]

........ I also was reading the post on ballistic approach recovery in the support and recovery forum and since I do not have any experience with High power or high altitude I have to ask this question, Is it not possible or correct, legal or ethical to launch a rocket to lets say 5000' let it fall to 100' or 800' and then just have one chute open and recover.
John

Hi John, check video , it's not about going ballistic and open the chute at 500 feet, a drogue chute will open at apogee. The guy say at the start of the video that the word "ballisitic is use because the rocket go nose down , not because it go ballistic. So it's a Dual deployment



https://www.youtube.com/watch?v=L8ntuUXfYoM

 

[thomas]

Ok since i do not know your physics skills I will give a descriptive explanation.

When you deploy a chute you will decelerate the rocket.
This is somehow the same when you jump in a swimming pool. When you jump from 5m you are fine, but when you jump from 500m you might feel a little bit broken afterwards.

Stopping a rocket that is traveling at a high speed, will result in a huge force on you rocket, the parachute and the cords.
If all these parts can stand the force, everything is fine. But normally the force will be so large, that one of your parts fail. Most likely the cord fails and your parachute is ripped apart from your rocket.

 

[cerving]

There's a big difference between going ballistic and doing drogueless dual-deploy. With the drogueless dual-deploy, your rocket is typically presenting enough surface area so that its fall is limited to around 100 ft/sec or so before you pop the main. With ballistic, it's going to keep building up speed until it hits terminal velocity, assuming that it reaches it before you hit the ground. You could easily be going several hundred ft/sec, popping a main at this speed is going to cause the main to tear apart, the shock cord to tear or rip out the bulkhead, and possibly massive airframe damage. It's something that is to be avoided...

 

[John4645]

Ok. However people jump out of air planes all the time and the gear and stuff withstands terminal velocity. So is it that we cannot build a rocket or a chute/gear strong enough to handle it? Is it because of weight or cost issues? Thanks again.

 

[CarVac]

Ok. However people jump out of air planes all the time and the gear and stuff withstands terminal velocity. So is it that we cannot build a rocket or a chute/gear strong enough to handle it? Is it because of weight or cost issues? Thanks again.

A human puts his or herself into a draggy orientation (facing the ground, arms and legs spread out) before releasing their chute, so the peak speed isn't too high.

A rocket is very sleek, and will keep speeding up until it goes about 3 or 4x faster than a human does.

 

[jadebox]

A human puts his or herself into a draggy orientation (facing the ground, arms and legs spread out) before releasing their chute, so the peak speed isn't too high.

A rocket is very sleek, and will keep speeding up until it goes about 3 or 4x faster than a human does.

The parachutes people use also open slowly. They slow the fall down somewhat before they fully open to lessen the shock on the system (and the person).

-- Roger

 

[John4645]

Ok, Thanks for the answers.

 

[3stoogesrocketry]

40 foot diameter parachute deployment at Mach 2.95
https://www.youtube.com/watch?v=ojAc5cAg4Vg

Eric

 

[DizWolf]

This is a rocket coming in drougeless (main failed) From about 3500 feet. Rocket came down sideways, and sustained no damage when it hit and bounced.

This is a rocket which came in ballistic (main failed) From about 1700 feet. it was doing 300 MPH when it hit the dirt.

It's much safer to break up the rocket at altitude, and let it fall. If the recovery fails, it's less of a danger than if it comes screaming in. The other issue is opening at high speeds requires very, very strong components.

 

[Handeman]

Terminal velocity for a rocket is about 300 mph, or 440 ft/sec. Here is the NASA terminal velocity calculator. You can even find TV for other planets.