WARNING AND DISCLAIMER: If you are underage, then consult with your parents or guardians before attempting any of this. You are on your own - I'm not responsible for your actions or harm you may bring to others because of your actions. Making the items described below can result in injury or death to you or people in your vicinity. Some things mentioned here may be illegal to make in your city, county, state, or country so check the laws that apply to you before you attempt anything described here. These notes are not complete on purpose. If you are reading them and new to pyrotechnics, then you are making a mistake. Stop now - this page is not for you. Get a beginning book on fireworks (see Skylighter or American Fireworks News (very quick shipping) for a start) and read up. You can't make any of this work without more information so read up or join a club or ask someone to help you.
Helicopters (Buzz Bombs)
Click on the image to see a rather anemic example of a buzz bomb (.wmv) This one has RP made with titanium so it has lots of sparks. This one was about 4" long and it seemed to be a little weak - they usually zoom up a bit farther. If you have trouble opening the above video, right click on it and save the target locally and then run it from your local machine. The following link is to a daytime launch that was considerably higher and better (but it was daytime!)
Daylight BuzzBomb Launch (click to play movie)
The above movie is of a good 3 1/2" Buzz Bomb flight that used RP .
1. There is a fairly big debate in the forums, books, magazines, and on vendor 'how to' sites about whether the guide sticks have to be warped so that they are propeller-like. It has been my experience (and apparently the experience of the general Chinese manufacturing industry) that screw type propellers are necessary for best performance. If you use RP , then they are mandatory to get the damn thing off the ground. Here is a video that shows my experience - click the image
2. The vent must be pointing down at 45 degrees to work best (8 or 4 o’clock when looking at the end of the tube) – don’t set it parallel to ground unless using very efficient (store bought) wings
3. 5 inch long Helicopters will burn through the case (not at the nozzle but along the bottom) using RP – keep them shorter (3” or so)
4. You don’t need to have a tapered plug at the bottom so that the exhaust is through a clay hole. For a ½” helicopter, just plug one end with clay and drill a 1/8th hole just above where the plug ends. They will still make it 50 or more feet high (about the same as the Chinese equivalent). Update to the 1/8th hole thingy... I tried it at 7/64's and it seemed to improve height and speed with RP .
5. These things do a strange dance… they rise up to a certain level and then linger. After a few moments, they then seem to get a boost and swoop upwards – sometimes quite high. A 5/8” x 4 helicopter rose to about 10 feet and hung for seconds just humming away. It then zipped up to about 60 feet or more before it ran out of fuel. Very strange but cool. See the daytime launch video just above this list - you can see the last minute bounce. It isn't as pronounced as it is in some of the launches but look for it in the last seconds of the burn.
6. Here’s my idea of why they do the bounce thing: They are normally off-balance – the wing and vent are at the opposite ends of the device. As the fuel burns, the CG of the rocket moves towards the wing center point, the wing starts to pivot more closely about its axis, thus it gets more efficient and more lift is generated.
7. I tried putting a BlackCat firecracker in the nose (I have a picture somewhere). I tied it in with hot glue and it looked very cool. Unfortunately, it must have screwed up the balance because it flew sucky.
8. It seems that the propellant shouldn’t pass under the wing – at least not far under it. If the tube is filled to capacity, it tends to have trouble getting airborne. Of course, this sort of contradicts my theory in item 6.
9. Wings are made by twisting Popsicle sticks (different names for these in different countries – they are sticks that ice cream treats are often served on). The twist is 90 degrees. The stick will break unless you heat it first. I heat a pan with a few tablespoons of water in it, drop in a hand full of sticks and let them warm up. You can then twist them with no problem. You must keep them twisted until they cool down (and dry). I built a frame for this. Saw a slit down the 9” length of a square of pine, on another square, saw about a dozen cross cuts about 1” in from the ends. Assemble the two squares with two end pieces so that the distance between the two pieces with slits in them is about ¾” less than the length of the Popsicle sticks. See the photo. This allows you to make a dozen wings in about 10 minutes and they work great. I hasten the drying by putting them in an oven heated to about 300 degrees for a few minutes. It dries them quickly. Take them out and let them cool while still in the rack. After cooling, remove them from the rack and they will have permanent twists.