1km with 18mm

[Matt]

do you think it would be possible to make 1000 meters on a 18mm rocket i ve been thinking of this for about 10mins now (early stages) hahaha
but do you think it would be possible to do with a D3 or somfing using an PICO ALT as ythe altimeter.

 

[dluders]

1,000 meters equals 3,280 ft (approximately). It would be tough to achieve that altitude with a single 18mm motor (such as an Estes C6-7). However, if you had a MULTIPLE-STAGE rocket, it could be possible.

The 3-stage Estes Commanche III rocket (with a D12-0, C6-0, and C6-7) can achieve altitudes of ~2,600 ft., but it uses a 24mm D engine. If you need to go 3,280 ft (1,000 meters), you'll probably have to cluster the first stage with several 18mm C6-0s.

I like using the PICO Altimeter ( https://www.geocities.com/rdh82000/Picoalt/index.htm ) . It's very small and lightweight. However, with it as a payload, you will decrease the maximum altitude achievable with your 18mm multi-stage rocket.

 

[jflis]

if you went min diameter and stripped as much weight from the design (putting the altimeter into a hollowed out nose, for example) it would be doable with a multi staged rocket.

It would be interesting to SIM different designs, but look at the FlisKits Cougar models (under competition kits) for your generic shape and go from there.

jim

 

[Mike]

I can't check right now but I think I simmed a 3-stage 18mm rocket that went to over a km, I'll have to try and find the file.

 

[kgholloway]

I just ran a "quicky" simulation using the following components:

parabolic balsa nosecone
12" mylar parachute and 18" 24# Kevlar shock cord
a single length of BT-20 Estes' tubing
an Estes' engine block
and 3 minimum sized 1/32" G10 fins

with the result being a maximum altitude of 3,850' using an Apogee D3-7 single use motor.

I'm not sure what the PICO altimeter weighs so I couldn't allow for it, but it looks like your 1km on a single 18mm motor is at least possible.

Ken Holloway

 

[sandman]

kgholloway,

Just for fun. Would you run the simulation again please, but this time plug in an 18mm D21-7 SU Aerotech motor...just curious.

OH yeh...what would be the maximum velocity with the D21 motor?

sandman

 

[kgholloway]

Sandman,

I'll be happy to re-run the sim. It will have to wait until Friday since I ran it on my office machine and I'll be out of town tomorrow.

Ken

 

[Matt]

after doing some sims on the rocsim demo it looks to me that i will need to do a two stage to make it i have mannaged 2900 ft with single stage

 

[kgholloway]

Sandman,

Here is the simulation data you asked for. Please note that this is for the minimum weight rocket without an altimeter.


Motor Max Altitude Max Velocity

C6-7 1764 ft 619 ft/s
D3-7 3850 ft 474 ft/s
D13-7 2960 ft 934 ft/s
D21-7 2489 ft 1110 ft/s
D24-7 2715 ft 1091 ft/s



Frankly, I can't explain the disparity between the D21-7 and the D24-7 altitude and velocity figures. It might be due to the heavier weight of the aluminum reload case vrs. the light weight phenolic case on the D21 single use motor.

Ken Holloway, NAR #78336, L-1

 

[n3tjm]

If you can find an old Aerotech 18mm E45 or F55, that should do the trick

 

[rocketfreak]

Hey,

My friend an I did a night launch of an F55 (kinda off subject, I know). That was cool! It had a 4in sky blue flame. It was awesome. Too bad we only had the one *sigh*.

-Chris H