Model Rocketry

jeancalvinus · August 12, 2009, 01:03:31 AM

WOW! The local hobby shop is pretty much matching the AC Supply price on rockets for our program! That is fantastic! And it isn't like they are a flash in the plan operation either, they are the only dedicated shop in the area and their owner is active in the local RC club.

I am really looking forward to breaking that news to the other senior members. This will both keep the cost low AND help our squadron establish a good relationship with a local supplier. Hopefully, after the cadets get their badges we can have regular launches.

By the way, I have built the goddard rockets (as I mentioned earlier) and have been experimenting with different configurations for the fins. I was able to get one to fly 80'6" (horizontal distance), and after speaking to the hobby shop owner, have some ideas on modifications that I hope will get me over 100.' I think I have launched that thing AT LEAST 100 times. Oh yeah, and I also found a good source for industrial strength rubber bands: that same hobby shop. They use them in wind up airplane models.

Sorry for all the gushing, but I find this rocketry stuff exciting!

Thrashed · August 14, 2009, 02:59:52 PM

Try Fliskits rockets. They are what Estes used to be in the '60-70's. Call him, he's very helpful.

http://www.fliskits.com/index.htm

Thrashed · August 14, 2009, 03:04:02 PM

Here's my 1/2 scale Harpoon missile. I'm launching it again this weekend on the same motor. K555

http://picasaweb.google.com/PoconoWargaming/MiscFile#5279474898648295906

jimmydeanno · August 14, 2009, 03:18:16 PM

^What kind of altitude are you getting out of the K555 with that rocket? Specs say you get 3.0 seconds of burn time with ~1,600 Ns...

Thrashed · August 14, 2009, 03:51:14 PM

2046' K555
3294' K950
2943' K670

About 21 lbs at launch.

jeancalvinus · August 17, 2009, 03:01:07 PM

We just finished the Redstone phase, and the cadets really enjoyed themselves. The fizzy flyers went as high as 12 feet (no joke) and as low as not leaving the launch pad (leaky film canisters). It seems the clear film canisters with the internal cap ring (which is shown in the CAP guide) give the highest flights.

The Goddard rocket was a blast, we had contests on height of flight and on distance. The furthest was around 50 feet, and the highest was about the same (height of course was a pure guess).

Our 2d phase practical will be August 29. I really look forward to it! We will be launching Gnomes, Vikings, and Patriots (all Estes).

Thrashed · August 17, 2009, 11:36:01 PM

Saturday's flight on the K555 went to 2236'.

jeancalvinus · August 18, 2009, 04:59:20 PM

BTW, has anyone tried building and launching the paper rockets (they are actually card stock) as an alternative to buying rockets? There are several plans online (there is even one specifically for CAP prepared by a Senior Member):

http://rocketry.wordpress.com/ultimate-paper-rocket-guide/

the link for the CAP rocket:

http://nmwg.cap.gov/santafe/Activities/CAPRocket.htm

The obvious advantage here is money: much can be saved. The DISadvantage is TIME: it would take a great deal of it to do this successfully, which would greatly stretch out the training days needed to get the program completed. It would take some dedicated cadets to see this through. There is a design available for every requirement, but it seems the time involved for construction would be high. Any thoughts?

I am trying the "midnight express" from fliskits to see how long it takes to build. Gonna scale it for "A" engines. I will keep ya'll posted.

Spike · August 18, 2009, 07:10:03 PM

Would anyone be able to direct me to the test from NHQ. I do not see them listed in E-Services. Must I fill out a Form 8??

davidsinn · August 18, 2009, 08:25:40 PM

Quote from: Spike on August 18, 2009, 07:10:03 PM
Would anyone be able to direct me to the test from NHQ. I do not see them listed in E-Services. Must I fill out a Form 8??

You're supposed to send an email to NHQ but the email listed is no good.

Spike · August 18, 2009, 08:28:57 PM

^ Great.........

davidsinn · August 19, 2009, 01:18:14 AM

Quote from: Spike on August 18, 2009, 08:28:57 PM
^ Great.........

That being said I just got in the mail today a set of tests by emailing the cadet test email and she forwarded it to the correct department.

helper · August 19, 2009, 03:17:19 AM

Quote from: jeancalvinus on August 18, 2009, 04:59:20 PM
BTW, has anyone tried building and launching the paper rockets ...

Yes, I've helped cadets to built rockets from FedEx envelopes & boxes. The body tubes and nose cones are from the envelopes. FedEx envelopes have a 'coating' that makes them quite durable. The small box is used for the fins. Use ES marking tape for streamers or BestBuy small plastic bags for the parachutes, yellow makes them more visible.

The cadets have been able to make all 3 of the rockets on a Saturday. The build time is faster if the fins are precut. I also make extra body tubes. The scale rocket body tube can be done using card stock with an ink jet printer to add a realistic design.

Here is a 3 'E' engine paper rocket that I put together while watching TV.

jeancalvinus · August 19, 2009, 06:10:49 PM

Helper, thanks for the picture! And I like the low-cost recycle approach of using fedex envelopes!

Question: do you have a problem with "scorching" the inside of the body tube? I have heard that is a issue with paper rockets.

I am trying one to build one as we speak. The nose cones are tricky it seems, but we'll see how the one I am working on now turns out.

jeancalvinus · September 01, 2009, 02:15:52 AM

well we had our phase 2 practical and flew Viking and Patriot rockets. max altitude on the Patriot was 508 ft (single station tracking) on a C6-5, the vikings were too tough to track (overcast conditions and small, white, unpainted rockets).

I would post pictures, but as I do not have 100 posts as of yet, I am unable.

next phase we are trying to get a large enough field to do two stage rockets (I am going to try a three stage Comanche), and will pray of a sunny day so we can track them (gonna try two station tracking, it is far more accurate). The cadets are having a blast (pun intended)!

DC · September 01, 2009, 05:12:34 AM

Quote from: jeancalvinus on September 01, 2009, 02:15:52 AM
well we had our phase 2 practical and flew Viking and Patriot rockets. max altitude on the Patriot was 508 ft (single station tracking) on a C6-5, the vikings were too tough to track (overcast conditions and small, white, unpainted rockets).

I would post pictures, but as I do not have 100 posts as of yet, I am unable.

next phase we are trying to get a large enough field to do two stage rockets (I am going to try a three stage Comanche), and will pray of a sunny day so we can track them (gonna try two station tracking, it is far more accurate). The cadets are having a blast (pun intended)!

You can stick them on an image hosting site like ImageShack and post them without attaching them.

Thanks for the update on your unit's rocketry program, it sounds like it's been very successful so far!

jeancalvinus · September 13, 2009, 06:51:35 PM

Yesterday was our third phase practical. We launched 3 payloaders (Estes Eggscaliber) and 8 two stage rockets (CC Express). We had probably the most fun we have ever had as a squadron in the time I have been there.

The payloaders did not go very well, only one of three functioned the first time, and of the two remaining, one functioned the second try. The other played lawn dart twice, mostly because (I think) the motor mount is designed to slide around a little depending on the size motor utilized. This allows the motor to slide into the rocket body a bit, and if it goes too far, it creates negative pressure and no thrust (even though the rocket motor is burning). I was on tracking station #1, and both times it went up, it left the launch pad and then immediately began its apogee turn over. It was funny too, both times the parachute deployed about 5 feet from the ground.

We had a few cadets who had to complete two phases of the practical, so we had 3 Gnome rocket launches. Those flew between 122 and 231 feet, and looked quite wimpy compared to the other rockets, but we launched them first so many didn't know the difference.

Next up were the Patriot rockets for a few cadets, and from my vantage point (800' from the launch pad), those were beautiful flights. Our three rockets went 527, 632, and 645 feet respectively. Two had successful parachute deployment, while the third was a lawn dart.

Then came the CC Express rockets. These launches were the most spectacular, with flights of 1439, 1493, 1498, 1543 feet (we had three flights where the rockets flew over the tracking station, so no altitude readings were possible). 5 flights had successful booster stage recovery, with clean parachute deployment. The CC Flies on D motors, and as these were the first D motors we have ever used, we were impressed. Those CC rockets just plain "rocket" off the pad, and really zoom on sustainer motor ignition. The D12-7 provided a very easy to track apogee smoke trail, and is perfectly matched to the CC.

Launch conditions were marginal as to the wind (borderline no-go wind at 9 knots), but the cadets handled the launch duties and did a great job tilting the launch rod into the wind. We were in a field that was about 2500 feet across, and 4 miles long, and as the wind was parallel to the long axis, all rockets were recovered that deployed chute. Tracking conditions were PERFECT, not a cloud in the sky. I did the two station tracking technique, using theodolites on loan from the college. We set our two stations up about 1100 feet part, leveled them up, and then setup the launch site 960 feet from one station and 785 from the other. This meant good accurate data for the Patriots, Eggscalibers, and the Gnomes, but lousy for any two-stage that tracked towards our stations. I read NASA on the topic last night, and they say minimum distance from the launch pad should be at LEAST as far as the highest expected altitude. Lesson learned--which means finding a new field for the next launch as we will be launching the 3 stage Comanche 3 on E-motors (over 2600 feet of altitude) and this field's dimensions won't allow us to setup our track.

I wrote a spreadsheet for data analysis from the tracking stations, and it worked great. Still a few bugs to work out, but overall good data.

The most spectacular flight occurred when a cadet mistakenly loaded 2 D12-7s in the same CC Express. Up went the rocket, and off went the engine, with no 2d stage motor fire. the rocket perfectly arced over at apogee, then the 2d motor fired, with the rocket pointing right at terra firma. That rocket went supersonic in it's gravity assisted flight and SLAMMED into the ground, with the motor still firing. Eager cadets tried to run to the rocket while it was still smoking, but were corralled by a quick acting SM. We all went over after a minute or two, and the rocket was a total loss, a smoking hole in the ground.

The nose cone was buried about 8 inches deep (and to add insult to injury, in a cow pie). We all hummed an impromptu "TAPS", much to the chagrin of the cadet who launched it. She did take it all in stride though. Another note: those CC Express Rockets are a bit sturdy--one had no chute and lawn darted from 1500 feet of altitude, but was able to fly again.

The scenery was great. We launched in a mountainous valley (in a rancher's field), and it was just beautiful. The cadets handled the launch duties, and safety considerations were properly observed (the cadet commander was more safety conscious than the SM were). We probably laughed more than we ever have at any single event. If you haven't done a rocketry program, do it. It will be a real joy for your cadets. :clap: :clap: :clap:

DC · September 13, 2009, 07:07:12 PM

Sounds like you guys have a great program running. Would you mind emailing me the spreadsheet you cooked up? I'd like to use something like that of and when we manage to secure funding to do our program...

Thrashed · September 14, 2009, 12:25:41 AM

you can find lots of forms and spread sheets free from estes.com

http://www.esteseducator.com/content/publications.php

Rob Sherlin · January 17, 2010, 05:08:59 AM

I don't hold "NAR" or "Tripolli" high power certification, but I had the experience working on, and launching high power rockets with a buddy of mine when I lived in California. It kind of seems to me that CAP's rocketry program is very fundamental, and deals more with history than actual knowledge of rockets. How many know how to read the engine numbers to decide what type of engine to use?..How many have designed and built rockets from scratch with a just a variety of tubes and balsa sheets?
Right now, I am currently working on a Fliskits "Tres" (3 cluster), but it's being modified to become a 2-stage rocket by modifying the engine mounts to take "D" class engines (upper stage will carry "C"), and will carry a 2 event timer chip as it's payload, with 2 seperate recovery deployments for each stage.
I want to get the Cadets into more of designing and building (therefore learning more than just building a kit by instructions), so they will learn more, have fun, and want to go further.