Lakeroadster's Estes Logo Rocket

[lakeroadster]

Here's my take on a rocket styled after the Estes Logo Rocket.

29mm power, rear eject spool.

I'm surprised Estes doesn't sell a kit like this?

@Marc_G took a stab at scratch building one of these back in 2012: Estes Logo Rocket... No idea how I'm gonna do it...

 

[neil_w]

I would love to understand why @Marc_G 's model was unstable.

 

[Antares JS]

Huh. I always assumed the Estes logo rocket looked conical because it was receding into the distance, not because it actually was conical.

Regardless, should be interesting. Have fun with it.

 

[Daddyisabar]

Just a whole lotta no good, stinking, performance robbing nose weight! Get that CG up there like a good cone needs with a punchy motor.

 

[lakeroadster]

Just a whole lotta no good, stinking, performance robbing nose weight! Get that CG up there like a good cone needs with a punchy motor.

Actually... no ballast was added on this one.

I would love to understand why @Marc_G 's model was unstable.

Yeah, me too. Sim's as stable?

 

[BABAR]

Seems like a good candidate for an internal launch lug.

 

[kuririn]

Airframe is very similar to the Sprint ABM.
Now if you can only get it to go zero to mach 10 in 5 seconds...............

 

[BABAR]

Maybe rear eject, with a small external shock cord loop on the “non pretty” side of the rocket (like the side of the Christmas tree you put against the wall.) in fact, you could use card stock to roll most if not all of the cone, again the seam would be the “non-pretty” side of the rocket. Maybe put the forward exit hole for the launch lug/rod on this side as well.

The external mount is place forward of the rocket body CG as measured WITHOUT the pop pod, motor, shock cord, and laundry. So body descends at angle but with pointy nose up.

 

[Daddyisabar]

Trust the Machines! If they say no nose weight then launch with safety and confidence. Confidence is key! Fins on the bottom rock.

 

[lakeroadster]

Seems like a good candidate for an internal launch lug.

Maybe rear eject, with a small external shock cord loop on the “non pretty” side of the rocket (like the side of the Christmas tree you put against the wall.) in fact, you could use card stock to roll most if not all of the cone, again the seam would be the “non-pretty” side of the rocket. Maybe put the forward exit hole for the launch lug/rod on this side as well.

The external mount is place forward of the rocket body CG as measured WITHOUT the pop pod, motor, shock cord, and laundry. So body descends at angle but with pointy nose up.

Here's my take on a rocket styled after the Estes Logo Rocket.

29mm power, rear eject spool.

Internal launch lug, similar to the way I did them on My Saturn V and Razorback. It'll be cut flush with the cone. Not exactly sure how I'll do the cone.

 

[hobie1dog]

I keep saying it: all of your rockets make me aware of how primitive of a modeler I am.

 

[lakeroadster]

I keep saying it: all of your rockets make me aware of how primitive of a modeler I am.

It's all good, and as long as your having fun and enjoying what you're doing, keep on keeping on.

To tell the truth... I'm about ready to find a new hobby. I'm just not in a good location for flying rockets, it's too dry here at my launch site and I have zero interest in big group launches where High Power is being flown.

Even though it's been raining here for a couple weeks, there's 1 to 2 foot tall dead grass that makes launching just a bad idea. And with the wonky mid power stuff I build, I'd hate to start a grass fire.

I miss the days of my youth when we flew in my Dad and Grandfathers hay fields in Ohio where fire bans never happened.

 

[Cape Byron]

To tell the truth... I'm about ready to find a new hobby.

Do tell...

 

[hobie1dog]

To tell the truth... I'm about ready to find a new hobby. I'm just not in a good location for flying rockets, it's too dry here at my launch site and I have zero interest in big group launches where High Power is being flown.

This would be a major loss to the forum if you go.

 

[bad_idea]

To tell the truth... I'm about ready to find a new hobby. I'm just not in a good location for flying rockets, it's too dry here at my launch site and I have zero interest in big group launches where High Power is being flown.

Water rockets.

 

[eugenefl]

To tell the truth... I'm about ready to find a new hobby. I'm just not in a good location for flying rockets, it's too dry here at my launch site and I have zero interest in big group launches where High Power is being flown.
<snip>
I miss the days of my youth when we flew in my Dad and Grandfathers hay fields in Ohio where fire bans never happened.

I cannot begin to tell you how much this post resonates with me. I'm in Florida where rockets are banned in all public parks city/county/states and there is very little private open land near me (less than 1 hour) where I might stand a chance to request landowner permission. Anyone that owns land knows they have a target on their back due to its value and the potential for liability. Club launches most certainly have their place, but loading and clearing racks is a 30 minute turnaround per rack and you might get bumped or miss a round if they run out of pads. In a way, the busy club is a GREAT sign for the hobby.

As you mentioned, I miss the days of my youth when my dad would pick me up when he got home from work and we would drive to a nearby (less than 2 miles) field - no fences, no signs, no worries - and I would burn through the 8 or 9 motors I had purchased with mowing neighbor's yards. Sometimes a neighborhood or school friend would join us. As an adult, I just long for the simplicity of this situation where I can just pick a few rockets from the fleet and launch a few just before sunset or in the cool of the morning.

I keep leaving the hobby, but returning (reBAR), and it is always the nostalgia and longing to relive my youth. Reality always has a way of rearing its ugly head. I've kept my unbuilt (and built) collection. As the wife and I watch our only child make her way into adulthood we have plans of moving someplace more rural and most likely out of the state. She's 100% onboard living in a farmland with open fields and where I can have a shop to work on cars, woodworking projects, and whatever other hobbies keep me sane.

 

[boatgeek]

Is there a sports field complex near you that you could launch at in early mornings? A couple of baseball fields should be enough for the little stuff. The Saturn V will take a bunch more room.

 

[lakeroadster]

Is there a sports field complex near you that you could launch at in early mornings? A couple of baseball fields should be enough for the little stuff. The Saturn V will take a bunch more room.

Not that allows rocket launches. I've called local authorities, they are the one's saying to use the field with the 2 foot high dead grass.

Last time I flew there (2022)... this happened (see quote below). So launching there simply isn't the responsible thing to do...

When I recovered my mid-power (F42) Cygnus Probe Ship after its last flight, the end of the body tube, the kevlar chord and a small portion of grass around it was on fire.

I carry a fire extinguisher, shovel and rake, as well as 5 gallons of water to every launch. I was able to easily stomp out the fire and then dumped water on the area.

No worries in this instance. But it makes me nervous in respect to what would have happened if that rocket had not been recovered.

View attachment 531044 View attachment 531045 View attachment 531046

 

[neil_w]

Lack of launch opportunities (for whatever reason) definitely puts a damper on enthusiasm for the hobby.

 

[lakeroadster]

Lathe Turned Body

I scaled the design down to fly on 24mm motors, and changed the construction to a 3" solid redwood fuselage. Still a rear eject spool. Also changed the number of fins from 4 to 3.

The profile is now kind of a Parabolic Series, with a shape parameter of 0.125. To me, it just looks better than conical. More like a rocket, less like a witches hat.

​

 

[BABAR]

I don’t think nose weight will be required.

 

[lakeroadster]

Look Ma... No CAD

Made a sketch using Open Rocket to determine how deep to bore the 2" hole for the rear eject spool.... And bought a 2" dia. Forstner bit.

​

 

[lakeroadster]

A Boring Project

I used some rubber tape wrapped around the cone and shoved into the hole in the drill press table. This created enough friction to keep the cone from spinning while boring the 2" hole. The hole is about 4-5/8" deep.

Also installed a screw eye for the shock cord.

You can see in the photo that the 2" bore is a bot off center.

If I were to do this part again I would have bored the 2" hole into the redwood 4 x 4 first. Then chucked that 2" bore in the wood lathe. That would have ensured the O.D. and I.D. of the part were concentric with each other.​

Lesson Learned.​

Finished weight of the bored fuselage = 6 ounces.

​

 

[lakeroadster]

Fin Slots & Swing Test

Cut the fin slots using a chop saw, followed by a Dremel with a grinding wheel to make the depth a bit more consistent.

Then, just as a curiousity, I did a swing test .

The rocket fuselage is not stable.​

An Open Rocket simulation shows it to be very stable at 1.55 Calibers. Weird, right?​

​

I'm wondering if perhaps the conical body, and the step at the rear of the body, is somehow changing airflow enough to negate some of the base drag?​

​

 

[sr205347d]

Then, just as a curiousity, I did a swing test .
The rocket fuselage is not stable.An Open Rocket simulation shows it to be very stable at 1.55 Calibers. Weird, right?

Go back and look at my thread on Bellyflop Recovery. These bellyfloppers would be unstable in a swing test. The CP shifts forward at increased AOA. So the rocket is stable on the way up, but transitions to flop mode at apogee.

Trust the sim.

 

[lakeroadster]

Go back and look at my thread on Bellyflop Recovery. These bellyfloppers would be unstable in a swing test. The CP shifts forward at increased AOA. So the rocket is stable on the way up, but transitions to flop mode at apogee.

Trust the sim.

Your belly floppers have a really long length to diameter ratio, are way over stable, and don't benefit from base drag.

I'm not sure how any of that correlates to this short stubby rocket?

 

[sr205347d]

I'm not sure how any of that correlates to this short stubby rocket?

Trust the sim.

 

[lakeroadster]

Trust the sim.

Trust, but verify.

If it's not a previously proven design, and it doesn't pass the swing test, I won't be launching it.

@Marc_G took a stab at scratch building one of these back in 2012: Estes Logo Rocket... No idea how I'm gonna do it... I ran a simulation and it sim's as stable. And according to @Marc_G, it didn't fly stable.

 

[Daddyisabar]

After a lengthy incantation and an offering of the spent D12 3 casing that did not have an ejection charge that crashed my favorite rocket, I open the Forbidden Codex of the Dark Arts of Oddrocketry. Not science, but necromancy. Not computer simulation, but dangerous mind simulation.

Hear ye, hear ye. The CP of a dastardly tall cone is 2/3rds up it's length. Those Fins bring it down very slightly, so the CG needs to be way up at 2/3rds point for first flight. Your friend of the base drag hack has abandoned you. The machine generated stability is but an illusion. Only sinful amounts of no good, stinking, performance robbing nose weight will appease the multitude dark forces surrounding the evil cone. So much lovely motor thrust must be sacrificed at the alter of stability. The horror.

Many have flown the simple paper cone with modeling clay or the motor recessed way up, but the solid wood calls the earth spirit to bring it down, back to the earth element from which it sprang. Terra firma calls back those who dare to leave her. The Mountain Spirit rumbles as the swing reveals the truth.

Power and nose weight can solve many of your problems and that ain't bad. Trust in Thrust.

Must close the Oddroc Codex, that evil tome will destroy your mind if too much time spent there.

 

[BABAR]

I’ve already professed my ignorance on sim programs, but I am with @lakeroadster on this one. That step off may really throw this for a loop, a standard cone sim may not be applicable.

Rather than just throw darts as usual, I do have a suggestion that MAY be helpful.

@lakeroadster , can you try wrapping tape (maybe electrical/vinyl) tape around the gap to make this a “pure” smooth cone and retry the swing test?

Also, since @neil_w has justifiably corrected me that sim programs CAN prove cones are stable, I would ask, has anyone successfully DONE a swing test on a cone rocket? It may be that swing testing itself may not be valid for some rockets. My Ping Pong ball ring tail rockets flew great, but they swing tested consistently BACKWARDS.