LAPA 2 Building Instructions – PART 1
The Baseplate
First off, we start with the dimensions of the base plate. It’s made out of a 19 mm thick wooden plate, I don’t recommend OSB (oriented strand board) or something like that, because even it is painted and appears to be waterproof, this isn’t a great solution. One of the reasons is that it bends and bulks out when it is in contact with water. For every skilled man or woman, this should not be no problem to be cut out with a jigsaw.
The next thing you want to do is to paint it in a colour you prefer. You don’t want to paint it after you mounted all the aluminium rails and profiles. An even better preparation of the wooden plate is that you drill all the holes you need before you paint it, that way it is guaranteed that the wood is nearly sealed off completely. So cut the needed aluminium profiles to length as described in the picture of the baseplate assembly and take a brass angle bracket and fix everything in place. If you don’t have the same dimensions as showed in the drawings, be sure to leave some allowance (is this the right term?) between the now mounted aluminium profiles and the support legs that will fit into these slots.
Klick on the image for magnification
see description of image
So far so good, next time, I discuss the support legs, the connecting rod and the support leg stands!
Untill then, have fun!
kind regards
Andrew
To share my developments
Hello everybody,
in the next days and weeks, I’ll be uploading the building instructions for my LAPA II launch pad, since it is (sadly) no longer in use. Anyway, it’s been the perfect launch pad I created for myself and it never occured to me that any part of this pad failed on me.
So I decided to share the exact measurements via computer drawings with you.
Thank you,
Andrew
PS: Here’s a spoiler picture: 
Sneak preview
Here’s a photo I took from Ignitia IIb today a minute before launch:
A lot of things to improve, but the launch day went pretty good!
regards
Andrew
Quick Update
Hi guys, I passed my A-levels! With distinction! And tomorrow, I am going to make my fifth launch day, but it won’t be a long one, currently I have only one airworthy rocket.
BUT there is going to be new stuff tested on my launch pad, I got rid of the old garden hose and bought an air hose set for easier setup and pressurizing. If I get a pressure cylinder someday, I can just connect it instead of the car tire valve adapter I’ve made for my pump.
Well, I have an occupation at the moment, so the video and the other stuff are problably online next weekend.
regards
Andrew
Finaly, some spare time
Hi guys, it’s been a while since I have posted something here, but after I (hopefully) passed my written A-Levels, there is some time now before I head to the oral A-Levels. As a result, I spend the last three days in my newly arranged work shop in the garage to make new, more reliable parachute deployment systems. Of course I made lots of photos which I am going to show you.
The dual-parachute payload fully assembled (note the cable ties)
After I created a system how to name my payloads, I’ve decided to give the new parachute deployment system the name N-FM-02. That’s, of course, a code for the second version of my parachute system for narrow bodies (which means 1,5 Liter bottles)
What I found out is that it’s a lot easier and more rugged to join all the parts with cable ties instead of gluing them together. For my parachute deployment, I didn’t use cable ties and glue anyway, but my additional parachute compartment for a dual-parachute system is to be build up of light wooden plates and cable ties. It’s assembled fast and easily, great stuff.
Update on the altitude-meter
I also completed my altitude-meter which will be mounted on an ordinary tripod. You can level it so you are able to get the exact altitude. The calibration was a little bit tricky but fortunately trigonometry was part of my A-Levels. Now it’s very accurate, but to determine the real altitude of the rocket, you would need two of these kind, but I think some inaccuracy isn’t a problem. (We know the
Finally, my ready-to-use altitude-meter
distance between the altitude-meter and the launch pad and the angle in which we see the rocket, but the rocket does not ascend perpendicular, so this is the reason for two instruments.)
N-FM-02
This parachute compartment implies the parachute right at the top of the rocket. The nosecone is some sort of cover which is released after the Tommy timer runs out. It has lots of advantages, such as lightness and simplicity. On the other hand you need skills in curling the plastic bottles and some accuracy to get it to work properly and maybe a smaller parachute which fits into the nosecone. Another great thing about these payloads is the small amount of wooden plates you need. Just two cut out circles do the job. Gluing some parts together is also involved though, but I connected them in a way they hold together even if the glue comes loose.
The nosecone which can be changed
But I have to say that this is only an interpretation and modification of the In-line Parachute Deployment Mechanism which is developed by the team of Air Command Water Rockets. You can find this Payload here: http://www.aircommandrockets.com/day86.htm
As we say in Austria: I don’t want to adorn myself with other feathers.
Nevertheless, I can’t wait to test it out on the field, I’ve already build two of these, some spare nosecones and a rocket (Ignitia IIb) to see if they work. As I mentioned, the additional parachute compartment will also be tested, it’s designed to work with this N-FM-02, two parachutes and a large rocket. But for now, I don’t have neither tape nor cable ties left.
The plate on which the nosecone sits holding the parachute (the nosecone and the parachute will be attached to this cable tie here)
Development of the staging mechanism
Last year, I build a staging mechanism and tested it. Unfortunately, I had to abort the launch because of a hose clamp which was loose. (See my other post) Now, I consider reconstructing and improving the prototype, as I already saw some problems concerning the rubber bands, the plywood which gets wet and the connection to the main stage. But this will probably be done after my A-levels. And driver’s license. And vacation. And Civilian Service…
Ignitia IIb
Even it is just a rocket with 3 liters of volume, it is an example of a variety of new methods I worked on. The fins are now also attached with cable ties to plastic strips, which are taped on. A very flexible but strong connection which allows me to change a fin in the field if it is broken.
The robinson coupling is now equipped with polyamide washers, so I have less metallic parts in my rocket. As soon as I am able to work on a cooker, I try to make spliced bottles to increase air flow in the rocket.
The all-new Ignitia IIb
The connectors for the guide rail are now combined with a plastic strip, it makes it easier to attach these and make them stronger for the launch. The details will be in another post in the rocket construction-section.
So much for today, until next time!
Andrew
The altitude meter on a tripod, not finished
Some Plans found of LAPA 2
Hi guys, just a quick post for my blog, currently I am writing my areas of expertise for my A-levels during the easter holiday, so there isn’t much time left…
Anyway, I found some plans of my second Launch Pad, which could be useful to you. Either for inspiration or construction purpose, feel free to ask me if you want to know something in detail, I try to answer as soon as possible!
This drawing shows a 3 liter water rocket with camera and parachute module
This should depict a close-up view from above, showing all details about the guide rail and the bolts used
I hope you guys can see what I did here, you can click on the picture for the original size
That’s all! Untill next time guys!
Andrew
PS: You can share all pictures here if you like, I would be happy if you quote the link or something beneath it, thanks!
Books about model rocketry
Hi everybody, it has been a long time since I wrote something in here. Last week, I bought a quite interesting book about model rocketry, although I don’t launch pyro-rockets. But since I’ve got this book, I get awesome ideas about rocket constructions and even things which can be very useful for launching them!
The name of the book is “Handbook of Model Rocketry” and it is written by G. Harry Stine and Bill Stine. Apparently, it’s the official handbook of the National Association of Rocketry (NAR), and really, I was fascinated by all the things in there.
The link to the amazon-shop: LINK
I don’t know, but what really got my attention is the altitude-meter that was described in the book. This kind of theodolite is very simple and can measure the altitude of the rocket by using trigonometry – perfect! - It is quite nice and you can build one exactly the same if you follow the instructions in the handbook, but I thought I can design one by myself with the things I have here. Plus, in Europe, theres the metrical system, all things in the book are in inch. I like metric better. (Maybe because I grew up with the metrical system, so I don’t have a sense for the inch-system)
Anyway, I already got a few parts, the only problem are the wood-parts, but I will get them as soon as I can to show you the pictures!
This is a picture I found on the website of the NAR, it shows this theodolite you can build with the handbook.
Of course I will post my own plans and drawings in the next blog as well.
until next time,
Andrew
Launch Pad 2 – LAPA2 – Know-How
The first aspect which has to be considered is the ability of the launch pad to be easily transported (nice sentence by the way). This is the reason why it consists out of five main parts and some other, smaller ones:
Main parts:
Two legs with the former, round guide rails
The new two meter guide rail
The base-plate with the lever and so on
The seven meter pressure hose (an ordinary garden hose at the moment)
Other parts:
The third leg
The strut for the connection of the two other legs
bolts, nuts, everything like that
Of course, I would like to have a pressure hose for my launch pad, but unfortunately my home improvement centre does not have this kind of hose any longer. (“Due to lack of demand” argh!) As soon as I am going to a better home improvement centre, I will consider picking one up there. The garden hose prevents a lot of pressure from going into the rocket assembly.
Now, as it is winter and I am currently in the middle of my exams, I cannot launch my rockets. The question is, if I want to carry on this hobby next year when I am going to be at university in Graz. Nevertheless, my last (if it is?) goal is to get my two-stage water rocket to the launch pad. As you guys read in my last post, I had to abort the launch of this rocket. But I figured the problem out; it is now leak proof as ever and hopefully be launched soon in spring/summer this year. (Then I am going to have my driving license too – awesome)
Well, now I want to show you pictures of the Launch Pad, and with that opportunity I want to say thank you to everybody who is reading my blog and who had to wait so long for a new post! Thank you!
On this picture you can see what is required for the launch pad assembly. I have to add that there is no pressure hose on this picture. You can see the little plasic box where I put the bolts in.
The whole Launch Pad 2 assembled. You have to take your time to do this, but it’s not very difficult. Our nice garden in fall, when we picked apples (note the two buckets )
Now some technical details and interesting stuff:
The guide rail – very useful. If you are very careful when constructing the pad, you have to make sure everything is exactly in the place where it should be. (The garden hose connector aligned with the guide rail, for example)
Here you can see how I attached the two former guide rails with the new one. I used something between them, so the construction is very rigid and does not make something unexpectet when launching rockets. The good thing: The long guide rail can be put back a few centimeters, so rockets with a bigger diameter can fit into. The same thing is on the bottom of the pad. (next picture)
Here we can see the fixing of the two legs and the guide rail in the background – now fixed in order to launch rockets with a small diameter.
Now we focus on the triggering mechanism. As you can see here, the lever is the same I used on my old Launch Pad. The pressure hose is secured with zip ties. Very handy feature: I mounted a handle on the base plate so I can transport it comfortably.
Just another point of view.
Very important: If you use such couplings to abort a launch, you should make sure the connector is not lost in the landscape. The power with which the water is coming out here should not be underestimated.
Well, this is everything I can contribute for today, I hope you like this post.
Andrew
