Lakeroadster's Lifting Rocket

[neil_w]

For my money this is by far the most interesting rocket among @lakeroadster 's stable. Really excited to see it getting closer to maiden flight.

I don't know your plans, but if this were mine I'd fly it once and only once. That thing is such a work of art that, after proving it's flight worthy, I wouldn't put it at risk a second time. (The fact that you've made a matching stand for it seems like evidence that perhaps you're thinking similarly.)

BOOOOOOOO

I want to see this thing fly again and again.

 

[lakeroadster]

I don't know your plans, but if this were mine I'd fly it once and only once. That thing is such a work of art that, after proving it's flight worthy, I wouldn't put it at risk a second time. (The fact that you've made a matching stand for it seems like evidence that perhaps you're thinking similarly.)

I get your point. It really depends on the flight profile.

My Mercury LES is an impressive flight, but it goes AoA shortly after thrust stops and the coast phase starts. Then the laundry ejects at about 50 feet altitude. That one will be a shelf queen.

Kind of the same scenario with The Cygnus Probe Ship.

But if it flies stable throughout thrust and coast, and the chute blossoms near apogee... it'll be on the regular flight rotation.

 

[Daddyisabar]

I get your point. It really depends on the flight profile.

My Mercury LES is an impressive flight, but it goes AoA shortly after thrust stops and the coast phase starts. Then the laundry ejects at about 50 feet altitude. That one will be a shelf queen.

Kind of the same scenario with The Cygnus Probe Ship.

But if it flies stable throughout thrust and coast, and the chute blossoms near apogee... it'll be on the regular flight rotation.

No shelf Queens, fly it to destruction! The MR capsule flies just fine. Your journey to the Dark Side will not be complete until you build and use one of these!

A cat-o-eight tails. Designed specifically for silly oddrocs with motors in the wrong places...Now my best evil villain laugh...haha, haha, hahaha!

 

[techrat]

A cat-o-eight tails.

Shouldn't that be a "CATO-eight-tails"

 

[Daddyisabar]

Shouldn't that be a "CATO-eight-tails"

I am the ultimate Estes Homer and Shill. Complete confidence in all eight motors lighting and performing flawlessly. Cluster CATO problems I have had in the past, Whooshing Crane, Smaug, Sharknader and PS II kit bash, JUST FORGETABOUTIT!

 

[lakeroadster]

No shelf Queens, fly it to destruction!

Well, that ^^^ would certainly minimize the "Where / How Should I display these" issues.

The whip I made for The Lifting Rocket has (3) 5 ft leads running to each motor, to get the wires away from becoming entangled in the fins.

I eliminated the fishing swivel and instead just used a Key Ring. That's worked well on my other rockets. Here's the current recovery harness configuration.

Anybody see something you think is an issue? Feel free to let me know. Recovery Harnesses seem to be my Achilles heel.

FWIW: Open Rocket Simulation shows ground hit speed = 12.9 MPH

 

[Daddyisabar]

Good to get rid of fishing swivel. They are fine for LPR but this is a bit more. There are heavier swivels that would work on this one but a key ring will do. If the first flight is a success it's time for a fourth motor!

Going up is much easier than coming down.

 

[lakeroadster]

Good to get rid of fishing swivel. They are fine for LPR but this is a bit more. There are heavier swivels that would work on this one but a key ring will do. If the first flight is a success it's time for a fourth motor!

Going up is much easier than coming down.

I was planning on all 4 motors for the maiden flight, what do you think, just do the cluster of (3) first?

• Apogee with just the (3) D12 cluster and the D12 in the cargo bay is 503 ft.
• Apogee with the (3) D12 cluster only is 361 ft.

And those are likely generous numbers since Open Rocket doesn't account for thrust vector losses due to motor canting.

 

[Daddyisabar]

Go for four!

 

[lakeroadster]

Go for four!

Yep. More Thrust / Altitude Solves Problems.

I probably shouldn't have written that.. it may come back to haunt me....

 

[jqavins]

I was planning on all 4 motors for the maiden flight, what do you think, just do the cluster of (3) first?

• Apogee with just the (3) D12 cluster and the D12 in the cargo bay is 503 ft.
• Apogee with the (3) D12 cluster only is 361 ft.

And those are likely generous numbers since Open Rocket doesn't account for thrust vector losses due to motor canting.

Incidentally, and this truly only incidental, what is the motor cant angle? The thrust loss is easy to calculate, and thus it's easy to estimate by calculation the reduction in apogee.

 

[lakeroadster]

Incidentally, and this truly only incidental, what is the motor cant angle? The thrust loss is easy to calculate, and thus it's easy to estimate by calculation the reduction in apogee.

12 degrees... not much of a decrease in performance. Allowable motor thrust variations is about the same.

I just like to keep apogee above 400 feet, especially with a 30" parachute, to give the recovery device a chance to slow the rocket.

Also gives some time to get some good photos

 

[jqavins]

So each canted motor loses 1-cos(12°), or 2.2% of vertical thrust. Since these are three of four engines, the whole set loses three quarters of that, or 1.6%. According to ThrustCurve.org (and our friend John generally knows what he's talking about) allowable variation in motor thrust is 5%. So the loss due to the cant angle is less than minor, it's really trivial.

 

[lakeroadster]

So each canted motor loses 1-cos(12°), or 2.2% of vertical thrust. Since these are three of four engines, the whole set loses three quarters of that, or 1.6%. According to ThrustCurve.org (and our friend John generally knows what he's talking about) allowable variation in motor thrust is 5%. So the loss due to the cant angle is less than minor, it's really trivial.

Thanks Joe. I "cant" doubt those numbers....

 

[lakeroadster]

We drove by the launch site today and had a discussion with Launch Control (aka my wife). It was determined that no future launches can be made due to the amount of tall dry grass.

Major bummer.

Launch Control did suggest that perhaps a launch could be made in the event of a blanket of snow. later in the year.

 

[BABAR]

We drove by the launch site today and had a discussion with Launch Control (aka my wife). It was determined that no future launches can be made due to the amount of tall dry grass.

Major bummer.

Launch Control did suggest that perhaps a launch could be made in the event of a blanket of snow. later in the year.

Knowing when and where NOT to launch is a wisdom I wish more rocketeers carried. Virtual hat is off to both you and your wife.

 

[Daddyisabar]

Get in the Conestoga wagon and head to Hartsel for Tripoli Colorado launch with hardened, back country dudes. Sunday, 8 to 9 am start.

I think SCORE on Saturday in Pueblo is oddroc day!

 

[lakeroadster]

Why "Wood"n't Woodgrain Wraps Work... I don't know why I never thought about doing this in Open Rocket before?

 

[Raptor 2]

Have you done any OR drawings on this one? The drawings all appear to be Cad. What does OR say about stability?

 

[Raptor 2]

Never mind just saw your OR post,