Let's face it: radio controlled planes are expensive, especially if you are new to the hobby. Cheaper options are appearing every day, but for the most part, hobby-grade planes come with a big price. Flite Test's speed build kits and electronics packs are an option, but can also be pricey when all the components are purchased. In this Instructable, I'll be showing you how I built the Flite Test Tiny Trainer for under $100, electronics, transmitter, and hardware included. Of course, you can build any of their Mighty Mini series, or alter my shopping list and make any one of their planes. I've included literally everything you need to buy from Hobbyking to build your first RC plane. After building this one, you'll already have most of the materials needed to make another, so your next one will be extremely cheap!
FT Tiny Trainer Overview:
I'd like to give special thanks to Flite Test for providing the free plans for this project, and for helping the whole RC community with their videos and website.
Step 1: Your Hobbyking Order (International Warehouse Prices Shown)
These are the items I used in my Tiny Trainer. I wanted power, so I'm going with the Blue Wonder 1300kv. If you want a milder plane, the "Turnigy Park 250" with a 6x4 prop and 2s battery should work. I was originally going to use that buy I wanted power...some would say crazy power for a plane this weight. With the 2s battery and Blue Wonder motor, an 8x4 prop would definitely suffice, so you can substitute that if you're intimidated by power.
$23.55 - Transmitter and Receiver:
$10.45 - Brushless Motor:
$5.33 - 2S LiPo Battery:
$8.30 - 12A Brushless ESC:
$6.75 - LiPo Charger:
$2.69 - 9g Servo: (Need 2)
$3.01 - 8x4 Propellers
$1.90 - Servo Extensions:
$1.03 - Control Horns: (Will need to widen the holes to 2mm)
$1.85 - Push Rods: (UPDATE: these are not worth buying, they are way too thick. Refer to my "Other Purchases" step)
$1.59 - Linkage Stoppers:
$2.77 - Velcro:
$0.30 - Heat Shrink:
$1.93 - JST Connectors:
$1.83 - Bullet Connectors:
Step 2: Other Purchases
$1 - Adams Readi-Board: Available at Dollar Tree stores (Need 2 sheets)
97 cents - Bamboo Skewers: Available in packs of 100 (or more) at Walmart or any supermarket
$4.97 - 8 AA batteries for the transmitter. I was still under $100 on my total price, so I threw these in.
Pick them up at Walmart if you need them.
UPDATE: These are pushrods that should work. The first link is for 36" long, and the second is for 12" long. If you mount the servos near the tail like I did, the 12" should suffice.
12-inch (free shipping at time of update: https://www.amazon.com/Music-Wire-032-Diameter-Lon...
Step 3: Tools & Other Items
There's no way to know what tools every individual has already, so I won't include any in the total cost of this project. Chances are you will have all of these items or will only need to buy one or two.
Soldering Iron: Cheap at Harbor Freight Stores, or you can borrow one from a friend (please return it when done)
Solder: Can also be found at Harbor Freight (or borrowed)
Razor (Utility) Blades: Harbor Freight has many types and quantities of blades for cheap
Hot Glue Gun: Walmart offers many kinds
Hot Glue Sticks: Walmart and other craft stores sell big and small sticks
Tape: What store doesn't sell tape?
Rubber Bands: Walmart or Dollar Tree, or any supermarket
Step 4: The Motor Mount
I made my motor mount to fit the Blue Wonder 24 gram motor. I have access to a laser cutter, so it was easy enough to model the firewall and cut it out in plastic. I used the screws that came with the servos to mount the motor.
Because the diameter of this motor is larger than that of the recommended 250 size, I modified the little motor pod. It was wide enough, but not quite tall enough. I increased the motor mount size to 30x30 mm so I could fit the Blue Wonder right in the center. I also extended the sides of the motor pod to 26 mm, so the total height of the finished pod would be 30 mm to fit the motor mount. For further modifications, look at step 7.
Most people don't have access to a laser cutter, so fortunately there are other options. You can cut and drill wood or plastic yourself, or you can buy wooden firewalls from the Flite Test store and use a smaller motor that will fit better. http://store.flitetest.com/mighty-mini-firewalls-5...
I guess you could try making your motor mount out of foam board, but I doubt it will perform as well as a traditional firewall. If you're brave (or cheap) enough to try this, I would suggest removing the paper from the foam board.
Step 5: Things to Note About Hobbyking Items
The battery charger I selected doesn't come with an American-style cord. This wasn't a problem for me - I just used an old laptop charger cord that's shown.
I didn't end up using everything from my shopping list. I explain this in a later step.
Step 6: My Costs
I ordered from the USA West warehouse on Hobbyking, so the prices are a bit more expensive than those listed for the International warehouse. My order total includes every single item listed on my shopping list. Select the warehouse you wish to buy from on the product page, or find a substitute item that is available from a different warehouse near you. In my state, tax is 6 cents on the dollar.
My Order Total: $81.94
AA batteries: $5.27
Foam Board: $2.12
GRAND TOTAL: $97.76
Keep in mind that shipping and tax changes depending on where you live, so you might not get your cost under 100 dollars. This Instructable is just showing how I did it.
You may already have 8 AA batteries or other items, so that could really keep the price down. I tried to include every single purchase (with the exception of tools) you could possibly make and still keep it under $100.
Step 7: Build the Plane
Using the plans provided by Flite Test and their videos on YouTube, you should be ready to build your plane. They also have videos on connecting electronics and soldering connectors. If you have any questions on how to use the connectors I chose or any other inquiries, please leave a comment and I will respond quickly.
Without changing any zoom settings, I just printed the tiled plans onto regular A4 printer paper and taped them together.
Full-Size Plans: http://www.stonekap.net/ftplans/FT-Mini%20TinyTrai...
If you have access to a large printer, you can use the full-size plans.
Soldering Batter Connectors:
Another good video on soldering bullet connectors:
Step 8: Design Modification
I mounted the servos on the exterior near the tail so I could use the 12" push rods that were available from the USA West warehouse. This is why I included servo extensions in my shopping list - the servo wires aren't quite long enough to reach to the electronics near the front of the plane.
I got the idea from an article on flitetest.com that was posted by winglet.
Thanks a lot!
I also reduced the thrust angle of the motor pod as shown in the photo. I lowered it about a millimeter because I think this plane is a bit big for the thrust angle meant for Flite Test's Mighty Mini series.
Step 9: Tips
These are things I've found to make the build process a bit easier.
-Use a sharp blade! I used 4 different blades throughout my build because I wanted my cuts to be as precise as possible.
-To transfer the lines from the plans onto the foam board, I use a pin. I lay the plans over the foam board and poke tiny holes through the paper and onto the foam board, and then connect all straight lines on the foam board with a ruler and pencil. For curves, I pierce several holes along the curve and connect them freehand with a pencil. With the pin method, you can reuse the plans as many times as you want!
-For cutting curves, make 3-5 score cuts until you cut through the paper on the underside of the foam board. This makes the curves smoother and cleaner.
-Don't try to build it all at once. If you take your time and cut and glue in sessions, your handiwork will be much nicer. I stretched my build out over weeks, doing a little here and there, and it turned out very crisp and clean.
-Round the ends of your barbecue skewers with a file. They look nicer and won't be sharp.
-I cut the skewers that hold the motor pod in flush with the nose because it makes more sense to not have them sticking out in my opinion. If you ever want to remove them, just push them out partway with another skewer and pull them the rest of the way out.
Step 10: Fly Your Plane!
If you're a beginner (and you probably are if you haven't bought a transmitter yet), I would suggest watching the Flite Test Beginner Series.
Make sure your prop has the labeling numbers facing forward!
If you really want to keep cost down but want to practice flying planes before you crash your precious scratch build, there are apps on the Google Play Store that can help you get the feel of RC plane flying. Search "rc plane simulator" and you can find one that works. These are not very realistic, but if it gets you used to the controls and helps you prevent a crash, it's worth a try.
If you are really serious about the hobby, buy a flight simulator. I have no experience with these, and I believe they can be expensive.
If you crash, don't worry. Foam board is easy to repair with more foam board and hot glue! (But that's not an invitation to crash).
Please keep in mind that this is an introduction to the RC hobby, and once you buy everything on my shopping list, your future scratch builds will be MUCH cheaper - a couple more servos and an extra motor is all you would need to buy if you didn't want to rip stuff out of your first plane. You can unplug the ESC and take out the Tx/Rx, battery, and all the other hardware to use on future planes.
Thanks for taking a look at my Instructable! Feel free to ask questions in the comments.