Introducing dCal

dCal Blog 2018 Jun 02

I like building drones. Many people don't realize you can build a drone with inexpensive materials available at local arts and crafts stores. You can program it with free, open source software from Ardupilot and you can order the rest of the parts online from Amazon or drone shops like GetFPV, ReadyMadeRC, or HobbyKing.

If you're not ready to build a drone from scratch, you can buy a frame kit and add motors, propellers, and the rest of the electronics. Some of these kits are pretty good and there are countless videos on Youtube showing you how to put them together. If you need help choosing motors and propellers, eCalc is a great tool.

I made this video of the H4 Alien 680 Frame kit assembling itself...

But, you may be disappointed with these kits. Many of them are heavy and your flight times won't be very long. If you crash and break parts, you might have to buy another entire kit because many of the parts aren't available individually. Some components will only fit certain frames and this can be annoying if you want to try different motors, a different flight controller, or a different camera gimbal.

I was frustrated by all of the above.

Plus, I don't have a shop or a garage where I live. I have a good selection of basic tools, but I don't have a table saw, a lathe or routing table, or even a 3D printer. But can you really build a drone from scratch if you don't have a shop, fancy tools, and expensive materials?

Yes, You Can!

A couple of my friends suggested I write a blog about this so I've been doing that here on Ardupilot.org. My educational blog is called "Building a Better Quad Frame". Browse through it to learn about basic drone frame designs, and how to get started designing your own drone frame.

So, What's Drone Frame Calculator?

Once you decide to build your own drone, one of the most important elements is weight. Unlike an airplane, a drone has no source of lift other than its motors and propellers. The same is true for full size helicopters. In order to stay in the air, the motors have to spin. The lighter you make your drone, the longer it will stay in the air.

Drone Frame Calculator helps you build a lighter drone. Designing a frame starts getting complicated when you want to know if a 200mm x 60mm x 1mm piece of carbon fiber is lighter than the same size piece of 1/16" birch plywood. Is it? dCal will tell you! You don't have to buy a bunch of different materials, cut them, and weigh them just to find out which one is lighter.

Save Time and Money!

I've wasted a lot of time and money, cutting pieces of carbon fiber plate, only to find out I could have built something just as strong and lighter out of another material. Sometimes you need the strength of carbon fiber, and other times a piece of balsa will be strong enough. dCal will help you select different materials for each part of your frame before you buy or cut anything.

How dCal Works

It doesn't matter if you sketch your drone design on a piece of paper or on your computer. Make a list of the pieces- top, bottom, sides, arms, and so on. In dCal, Enter the size of each piece, then select from a database of materials. Each time you select a material, dCal will tell you how much your piece weighs. You can select different materials for different pieces. dCal also shows the total weight of all the parts in your "Project". Want to compare multiple designs? Create additional Projects.

dCal Beta

The beta version should be public in a couple of weeks. It will have the following features:

Create a free account and select a username. Like many online forums, there will be different account levels. New users won't have access to certain features (like uploading files, etc.) until they are approved.
Create a simple profile with an avatar and set it to private, community, or public. If your profile is set to "private", no one can see any of your projects. If your profile is set to "community", only other logged in members can see your projects.
Create projects. Each project has a title, a URL, a summary, and a full description. Each project can be set to public or private.
Add parts to a project. Dimensions are automatically converted between inches and mm or cm. The material of each part can be selected from the dCal materials database or it can be user-defined.
If you know the dimensions of a piece, dCal will determine its weight based on the material you select. You can try different materials and see how much the piece would weigh for each one.
What if you have a complex shaped piece with lots of holes and cutouts? (like a frame plate from a kit) If you enter its weight and the material its made from, dCal can tell you what it would weigh if it was made from any other material in the database. Thinking of using a composite sandwich? dCal will tell you how much it would weigh before you go to the trouble of cutting it out.
I have lots more planned. I'll be getting feedback from the DIY drone community and I'll be sharing some of my frame designs on dCal so you can see some real life examples. I'm looking forward to seeing what some of my friends come up with.

More to come...