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1st rocket for my grandson

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Grandpa_Dale

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I am planing on buying my grandson a kit for his birthday (12 yr). There is an athletic field a block from his house that would make a great launch area, but a poor recovery area due to a nearby highway. I have been looking for kit/motor combinations to have a fairly low max altitude to minimize drift, but I am getting lost on figuring out how high a given rocket will go with various recommended engines. Also, I am looking for opinions on wither the launch site is usable at all.

field.jpg

Thanks, Dale
 

Exactimator

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As a rule of thumb, fat (larger diameter rockets) stay low. Estes crayon, Freefall, Big Daddy, Der Red Max are examples. If you launch one of those on their recommended smaller motors, they won't go too high. On the flip side, a small Estes gnome will go pretty high on a small A motor.

You can poke around the Estes website and look at the recommended motors and altitude ranges for different rockets. For instance, with a Der Red Max Estes website says Recommended Engines : B6-2, (first launch), B4-2, B4-4, B6-4, C6-5 Projected Max Altitude: 600 ft. (183 m)

You can use thrustcurve.org to get a table of altitudes for different rockets and motors from the MOTOR GUIDE section.
Again, using a Der Red Max, for example:
Body diameter: 1.64 inches
Dry Weight: 2.4 oz (68g) This is the weight without the motor.
MMT diameter: 18mm (this is the diameter of the motors it can take)
MMT length: This doesn't really matter. Just put in 6"
Complexity: simple
Finish: average
Moto Mfr: Estes Industries
Motor type: All
Certified by: All

You get this table:

.............Motor ................Weight .......Launch .......Velocity ......Accel .........Altitude .......Time ....Delay
MotorWeightLaunchVelocityAccelAltitudeTimeDelay
Estes B62.9oz49ft/s137ft/s14.0G256ft4.0s3s
WEstes C53.3oz56ft/s211ft/s23.2G584ft5.8s4s
WEstes C63.2oz49ft/s219ft/s13.9G597ft6.0s4s

If you really wanted to be safe, you could get a B6-4. at 256 feet max altitude, that will hardly drift. On a windless day, you could do the C6-5 and send it up to 600 feet.
Your grandson can change the finish selection and see how putting a nice smooth paint job on affects the performance.

A Big Daddy is 3" around and takes the big 24mm C and D motors. Lots of smoke and noise with not too much altitude. Those are fun for small fields.
 

Exactimator

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On the flip side for an Estes Gnome
From Estes:
Length: 10.25 in. (26 cm)
Diameter: .54 in. (14 mm)
Estimated Weight: .5 oz. (14.2 g)

Recommended Engines: 1/2A3-2T, 1/2A3-4T (First Flight), A3-4T, A10-3T
Projected Max Altitude: 800 ft. (244 m)

From Thrustcurve:
.......................Motor ................Weight .......Launch .......Velocity ......Accel .......Altitude ...Time ....Delay

WEstes 1/4A30.7oz65ft/s89ft/s24.4G120ft2.8s3s
WEstes 1/2A30.7oz81ft/s165ft/s37.6G346ft4.6s4s
Estes A100.8oz84ft/s256ft/s55.7G725ft6.3s5s
WEstes A30.8oz69ft/s287ft/s25.7G832ft6.8s6s
 

Zeus-cat

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And you can use a streamer instead of a parachute. Streamers really cut down on drift and the rockets descend faster than on a parachute. You can use crepe paper streamers sold at party stores as it must be fireproof by law.
 

Grandpa_Dale

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That thrust calculator was very helpful. In the process of researching local park rules, I found that a park about 1/2 mile away is used by school science clubs as a launch site. That cures my highway concerns. A rocket coming down in someones back yard is an oops, one coming down on the hood of a car going 50 MPH is a OHHH SH*T!!!
 

Grandpa_Dale

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And you can use a streamer instead of a parachute. Streamers really cut down on drift and the rockets descend faster than on a parachute. You can use crepe paper streamers sold at party stores as it must be fireproof by law.
That was in the back of my mind as a solution.
 

JStarStar

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Good point on streamers allowing faster descent and as a result cutting down on drift, but keep in mind with that higher descent speed you may get some dinged-up fins on landing.

On a small field such as a football or baseball field surrounded by trees and-or highways, you'll want to keep a close eye on wind direction and speed.

Remember most rockets tend to weathercock, that is, curve into the direction of the wind, while under power, then drift along WITH the wind after ejection.

It's actually common for more seasoned rocketeers to tilt their launch rod into the direction of a light breeze, so the rocket will weathercock and curve into a low upwind trajectory, then when the chute/streamer ejects, it drifts right back down into your lap.
 

Scott_650

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If you're looking for something easy to make and fun to launch take a look at Art Applewhite's free paper rockets at www.artapplewhite.com. I had our vacation bible school kids build and fly these last summer. I still launch one in the back yard here at home when I just feel like making some smoke! Estes crayon rockets are great flyers on A and B motors but they're ready to fly so he's not going to get much building experience. Any BT60 based kit that builds out to 3 - 5 ounces would work well on an athletic field on A or B motors.
 

JStarStar

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Another good strategy to keep in mind is to make your first launch with the smallest recommended motor for the given rocket; that gives you a chance to keep an eye on it and see how it behaves in flight, especially in terms of weathercocking and chute drift. If you misjudge wind direction, etc etc, probably your worst case scenario is a walk of a couple hundred feet.

If you crank up with a more powerful motor, if you misjudge the wind, it may be na-na, hey-heyy-hey, goodbye. :y:
 

Bdpeters

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If you're looking for something easy to make and fun to launch take a look at Art Applewhite's free paper rockets at www.artapplewhite.com.

Applewhites flying saucer rockets are a good bet for low altitude plus lots of smoke and visual appeal. I have not tried his free paper rockets though.
 

KennB

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Take a look at the dooDad kit from Fliskits and any of their other Skill Level 1 kits. The dooDad and other Jig-Tech finned rockets are almost fool-proof to build and fin alignment is automatic. Great small field rockets that can be boosted higher when you're in the right place.
 

Bat-mite

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As for the field, it is plenty long enough, but the width is a kicker. As a rule of thumb, one should not plan to go higher than twice the distance of the smallest part of the field. For you, that looks like about 300' max altitude, which isn't much. Any larger options within the region?
 

Grandpa_Dale

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Take a look at the dooDad kit from Fliskits and any of their other Skill Level 1 kits. The dooDad and other Jig-Tech finned rockets are almost fool-proof to build and fin alignment is automatic. Great small field rockets that can be boosted higher when you're in the right place.
I settled on an Este Taser starter kit, mainly to get the launch equipment cheap, and a Este Viking level 1 as a first "project" rocket. I also got a pack of A8-3's for a minimum power first flight, and a pack of of B6-4's for a medium power second launch for both of them.
 

Nytrunner

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For the day when you decide you both want a Launchpad and launcher each ( :D ), Check out the Tandem-X launch set. It's got a great E2X (Amazon) and Skill-1 rocket (Crossfire). [Although Estes now calls them Skill-2 and 3 respectively.......]

If you've got a Hobby Lobby nearby, use the 40% coupon.
 

Cabernut

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Taser - good choice. It flies great on A8-3s, up to 200-ish feet. Starts getting altitude with Bs. REALLY gets up there on Cs.

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[youtube]kBJaKAs0x3M[/youtube]
 

BABAR

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I settled on an Este Taser starter kit, mainly to get the launch equipment cheap, and a Este Viking level 1 as a first "project" rocket. I also got a pack of A8-3's for a minimum power first flight, and a pack of of B6-4's for a medium power second launch for both of them.
For a cool look and less damage on landings, consider putting the Viking fins on swept forward the nstead of back. This way the rocket hits the ground engine butt first. Nobody cares if you ding an engine casing.
 
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