Rocket deviates after liftoff

[Samarth Barshi]

I am really confused as to why this happened. Stability was 1.2 cal( around10%) at pad clearance and exit velocity was 25 m/s with mild winds at 3m/s.
View attachment WhatsApp Video 2024-04-08 at 7.35.57 PM(2).mp4

 

[Art Upton]

That does not look bad for about 7 miles per hour wind on the ground. The wind higher may be more or less.

Where was the wind speed coming from, a weather report or your on site measurements.

 

[Samarth Barshi]

That does not look bad for about 7 miles per hour wind on the ground. The wind higher may be more or less.

Where was the wind speed coming from, a weather report or your on site measurements.

SW to NE and gusts from W to E.

 

[drewnickel]

A stable rocket will turn to minimize angle of attack. Unless there is no wind, you will have some non-zero angle of attack and the rocket will pitch over in response.

 

[Art Upton]

SW to NE and gusts from W to E.

Thanks, where did you get the wind speed reading from?

A device at your launch, or from a weather report?

 

[Samarth Barshi]

Thanks, where did you get the wind speed reading from?

A device at your launch, or from a weather report?

from weather app ventusky

 

[Samarth Barshi]

A stable rocket will turn to minimize angle of attack. Unless there is no wind, you will have some non-zero angle of attack and the rocket will pitch over in response.

so is there a way to minimise or its just normal? It didnt happen this much earlier

 

[Art Upton]

from weather app ventusky

Those will not totally match what is happening locally at your launch field. If your worried about wind affecting your altitude, you should get a wind speed meter for your team to mount at the field in an open area.

 

[waltr]

A common method when there is wind is to angle the launch rail with the wind. Then the rocket wind-cocks and goes straight up.

Was this at a club launch? If so then what did other rockets do?

 

[lr64]

Those will not totally match what is happening locally at your launch field. If your worried about wind affecting your altitude, you should get a wind speed meter for your team to mount at the field in an open area.

And maybe a streamer on a pole? That can give you an idea of how shifty and unsteady the wind is. If it's getting blown every which way, leaning a bit downwind may not be reliable. I remember when I was a kid, people would orient the launch rod slightly upwind so that the rockets wouldn't drift as far downwind under their parachutes. But those weren't high powered rockets.

 

[bobbyg23]

Because rockets. Stuff happens that has no good explanation

 

[cwbullet]

Because rockets. Stuff happens that has no good explanation

Isn’t that the truth.

Did anyone get a photo going off the end of the rail? Depending on the rocket and rail button placement, a rocket can go off the top the rail a little wonky.

 

[bobbyg23]

The ignitor leads could have still been attached also. I've had that cause a sudden turn.

 

[Art Upton]

And maybe a streamer on a pole? That can give you an idea of how shifty and unsteady the wind is. If it's getting blown every which way, leaning a bit downwind may not be reliable. I remember when I was a kid, people would orient the launch rod slightly upwind so that the rockets wouldn't drift as far downwind under their parachutes. But those weren't high powered rockets.

No You point the rocket DownWind slightly , into the wind makes it weathercock even worse, even LPR rockets; watch contesters and how they do it.. It is not about drifting but making it go straight up as best as possible for the best altitude.

See post #9 I am sure that Samarth is doing a contest as a team.

 

[Art Upton]

The ignitor leads could have still been attached also. I've had that cause a sudden turn.

The rocket is straight up well off the pad see the photo before it starts to move to the left of the photo. Lead and rail problems would have happened before that.

 

[bobbyg23]

The rocket is straight up well off the pad see the photo before it starts to move to the left of the photo. Lead and rail problems would have happened before that.

Nope. Mine was quite a ways above the rail when it happened. I didn't wrap the lead around the pad. Lead is about 20' long so it was up that high before it created tension and cocked over my rocket. I wouldn't have believed it if my friend hadn't gotten pictures.

 

[lr64]

No You point the rocket DownWind slightly , into the wind makes it weathercock even worse, even LPR rockets; watch contesters and how they do it.. It is not about drifting but making it go straight up as best as possible for the best altitude.

See post #9 I am sure that Samarth is doing a contest as a team.

That depends on how much of a hike you want to take and how you feel about climbing trees or losing your rocket. It is not a yes or no issue.

 

[Daddyisabar]

Slightly miss aligned fin? A slight breeze above the pad causing a slight weathercock? A slight malfeasance by the vengeful rocket gods? There must be an explanation based in science!

The variations in our atmosphere we launch into are a cruel mistress to the mighty model rocket flyer. Why, why did my Awesome model rocket not fly perfectly straight? Is there something fundamentally wrong? We may never know.

 

[cwbullet]

The ignitor leads could have still been attached also. I've had that cause a sudden turn.

Nice call. I have seen it too.

 

[Art Upton]

That depends on how much of a hike you want to take and how you feel about climbing trees or losing your rocket. It is not a yes or no issue.

It is different in a competition , and the fields at those meets are better generally.

 

[Azamiryou]

No You point the rocket DownWind slightly , into the wind makes it weathercock even worse, even LPR rockets; watch contesters and how they do it.. It is not about drifting but making it go straight up as best as possible for the best altitude.

If your goal is max altitude, angle with the wind so it weathercocks straight up.

If your goal is landing near the launch pad, angle into the wind so it will drift back.

 

[Daddyisabar]

The ignitor leads could have still been attached also. I've had that cause a sudden turn.

A plug for Tahoma Photography. If it does happen you need a good photographer to prove it did. Even worse on a questionable sports scale Maverick. Everything goes wrong all at once... and at the big national launch in front of all the top people! Oh the humanity! So embarrassing.

This wasn't my rocket but I did offer my rocket buddy condolences and a safe space/comfort food if needed.

P.S. He did rebuild it and the next flight was perfect, one of the best sports scale flights I have seen. Straight up, no spin, deploy at apogee and slow descent landing near pad.

 

[bobbyg23]

View attachment 639490
A plug for Tahoma Photography. If it does happen you need a good photographer to prove it did. Even worse on a questionable sports scale Maverick. Everything goes wrong all at once... and at the big national launch in front of all the top people! Oh the humanity! So embarrassing.

This wasn't my rocket but I did offer my rocket buddy condolences and a safe space/comfort food if needed.

P.S. He did rebuild it and the next flight was perfect, one of the best sports scale flights I have seen. Straight up, no spin, deploy at apogee and slow descent landing near pad.

That's how I figured it out. My friend was taking pictures.

 

[rcktnut]

I'll add thrust misalignment. My Mad Dog DD always flew straight as an arrow even in moderate winds until this flight. The winds were calm/ none/zilch/ nada, and yet my rocket took a turn. Not real bad but did not fly as straight as it normally does.
View attachment mad dag on skid - Trim.mp4

 

[Samarth Barshi]

A common method when there is wind is to angle the launch rail with the wind. Then the rocket wind-cocks and goes straight up.

Was this at a club launch? If so then what did other rockets do?

no this was the only launch

 

[Samarth Barshi]

I'll add thrust misalignment. My Mad Dog DD always flew straight as an arrow even in moderate winds until this flight. The winds were calm/ none/zilch/ nada, and yet my rocket took a turn. Not real bad but did not fly as straight as it normally does.
View attachment 639528

there might have been thrust misalignment.

 

[Samarth Barshi]

Slightly miss aligned fin? A slight breeze above the pad causing a slight weathercock? A slight malfeasance by the vengeful rocket gods? There must be an explanation based in science!

The variations in our atmosphere we launch into are a cruel mistress to the mighty model rocket flyer. Why, why did my Awesome model rocket not fly perfectly straight? Is there something fundamentally wrong? We may never know.

yeah maybe i will never know all i can do is shortlist the probable reasons and try to mitigate that in the next launch.

 

[Samarth Barshi]

The ignitor leads could have still been attached also. I've had that cause a sudden turn.

no it came out very soon

 

[Samarth Barshi]

And maybe a streamer on a pole? That can give you an idea of how shifty and unsteady the wind is. If it's getting blown ever

Isn’t that the truth.

Did anyone get a photo going off the end of the rail? Depending on the rocket and rail button placement, a rocket can go off the top the rail a little wonky.

 

[Daddyisabar]

yeah maybe i will never know all i can do is shortlist the probable reasons and try to mitigate that in the next launch.

You will learn the ways of the Jedi, opening your eyes to a larger world.