Crash Test Hobby

08/24/2026

I built a new Grim Reaper with a few variations including 3D printed control horns, a 3D printed motor mount with an extension to move the prop back farther from the back of the wing with a larger motor with a 9x6 prop to help quiet the plane and a 0 thrust angle on the motor. Here is my report.

"I didn't know exactly how the CG would come out on my new Reaper with the big heavy motor on the longer 15mm motor extension mount. I was sure it was going to be a little tail heavy, especially since I was only using a 2200 mah 3S battery in the nose and a massive motor behind the CG. The CG seemed a little back when I balanced the plane but I didn't want to add any weight and decided to test fly it anyway just the way it was. I don't recommend this for new flyers. There is a lot that can go wrong very quickly.

I wanted my new build to be strong but light and I wanted to use a bigger prop for lower noise level with a bigger gap between the back of the wing and the prop to help quiet the plane down but still to maintain power. I built crashtesthobby tough for combat but still considered how much weight I was adding with each step. Final weight came out at 43 ounces on a 4.3 Sq/ft wing so it comes in at 10 ounces a foot which is light enough it may slope with the motor off.

I have many good flying friends who helped but my son James, contributed in the cores, and Chuck and my brother Kevin designed the 3D motor mount and the printed horns, all of which were critical test parts of this build. Other flyers had input and ideas too. and Jeff gets an honorable mention for help with updating and printing.

I like to experiment, and we did a lot of work developing the 3D printed parts. I think Chuck did 7 versions of the motor mount before we finally chose the one we are using. If you want to see something amazing look at all the files and variations Chuck created for our different planes. Kevin designed the control horn and there were multiple modifications before we found some filament and a design that would work and felt would be strong enough to take abuse. My goal was to get a strong control horn with a bigger base that would work better with our EPP elevons.

https://www.crashtesthobby.com/3d-print-files-for-motor-mounts.html

I did not expect to have ballistic speed but I did expect plenty of power for long climbs and gentle aerobatics with the big motor and prop. With a 3S battery the big prop has a lower throaty sound.

[B]One other thing that is different.[/B] This is the first time in many years that we have put the motor without any down thrust like with do on the symmetrical airfoils. I did not have any trouble with the plane diving with the addition of throttle and so the 0 Motor angle worked well.

Flying....

On launch I am glad to report the plane flew out of my hand and climbed without a stall or rolling over because of being tail heavy. In fact it climbed with authority and I didn't have to give even one click of trim through the whole flight. I think this is a first even for me. It isn't a slow plane. It probably is flying around 90 mph and the flights were a reasonable length with the 2200 3S battery. We put and amp meter on it and it is pulling 31 amps wide open throttle which is less than I expected and that is why the motor is not getting hot and the 60A ESC is easily handling the load.

I climbed to three mistakes high and did a few turns and loops then cut the motor and tried to stall it and it didn't stall until the speed got so low that any plane would have rolled over with a lot of up elevator. I always worry about being tail heavy on landing as the plane is slowing down but the plane floated in and landed without any instability.

Even I am amazed and think it may be my favorite Reaper of all time. I flew 6 batteries through it and my only downer was I broke a prop on one of the landings since I was skidding it in on astroturf. I still need to figure out the prop thing....

3D Print Files for CTH Motor Mounts ______________________________________________________________________________________________________

08/17/2026

This is the first reply to a teacher requesting information and asking for our suggestions of which planes would be best for high school students. We love our flying wings but there are times that having a slower plane is going to have a better outcome.

Years ago we had a local university buy enough flying wings from us for each student to have one to use with their FPV and waypoint assignments for their students. They wanted more durable planes because everything they had used up to that point was broken or didn't fly very well.

They found that flying wings took too long to learn to fly because they were too fast and aerobatic. They only had a couple of students finish their projects that first semester.. They came back to us and asked if we could design a plane that was easier to fly and would fly slower with more conventional controls. I found it interesting that they even had two foam cutters but still couldn't come up with something that would work.

It was then we designed our EPP foam polyhedral wing Albatross. I based it on some of the old freeflight planes from the 50s and 60s that didn't fly with a radio but had to be able to be stable in the air with just their aerodynamics. I applied new materials to the old design and used the solid wing and solid fuselage design and EPP foam which is comparable to a Nerf foam that can bend without breaking. The solid wing and fuselage make it so even if it does break it doesn't crush and is very easy to repair with a hot glue gun at the flying field. We put the motor up on top on a pylon so they didn't break props and damage the motor if they had an accident.

We have sold a couple of thousand of this model to beginners and students both with the poly wing and with the aileron wing which we added later. One of the university students was hired by the military to run a RC training group. He contacted us and told me that all of their trainer planes were broken or didn't fly very well and he got several of our Albatrosses to use in some of the basic training they were doing. This is long before the drones that we see now.

The Albatross is a great trainer because it can fly at 15-30 MPH with relatively inexpensive radio and batteries. You can fly it in a smaller flying field than you can with faster planes. You can land on grass which means you don't have to have a runway. Landing gear adds weight and drag and also likes to rip off a plane in an accident usually damaging the fuselage.

Our flying wings usually fly 30 to 75+ mph with some going over 100 mph. It's fun to fly fast but it isn't a good way to learn. I was out flying today with an engineer and his 13 year old son. The 13 year old was doing aerobatics and catching his Albatross while his dad crashed his flying wing twice. I encouraged the dad to get an Albatross to learn on and then when he was comfortable flying to progress to a faster plane. The 13 year old has only been flying for a month and he is in control and having a lot of fun.

https://www.crashtesthobby.com/albatross-46.html

Here is some more information from our website:

https://www.crashtesthobby.com/my-advice-to-new-flyers.html

https://www.crashtesthobby.com/best-rc-trainer.html

Feel free to ask questions. We have a buy 5 get a 6th plane free for all school and club groups. As long as you buy more than 5 at a time you will get a discount for the entire group even if it isn't a multiple of 5.

https://www.crashtesthobby.com/discounts.html

This Email is a good place to reach us if you have more questions.

Lee

Three Ways to Save!!!

08/17/2026

I got a request from a teacher who wants to build a plane for each of 14 students. I told him that although we specialize in flying wings that he would have better success teaching a group of students with a slower plane. This is the second post to him.

You're not the first one to ask. Because of our connection to clubs and schools we have had many questions of how to get started with radio control. I'm going to let you know how I would do it seeing I have flown now for over 54 years. My son now runs the business but I get to answer a lot of the Emails.

We have always been cost conscious. Some flyers and dealers will try to sell you expensive radios and motors and batteries when less expensive equipment can work just as well. Let me show you how to save money.

You need to have someone with a little experience to help you get started. When the engineer and his son I told you about in the last email first started flying I told them I wanted to flight check their planes before I trimmed them out for flight. I found I had to reglue many of the glue joints and help them with radio and connectors and laminate to make their planes safe to fly. They had tried to build light and their servos were loose and connectors were set up with too much movement. This is actually a common problem and if you have someone who knows what they are doing it makes a lot of difference.

In order to help everyone, not just the local flyers. I made some build videos to demonstrate the building process to the customers who lived far away. We have shipped to 50 countries and not all speak English, so the videos let them build along with me even if they spoke another language. Take a look....

My advice to new flyers: https://www.crashtesthobby.com/my-advice-to-new-flyers.html

Here is a link to building instructions and videos. https://www.crashtesthobby.com/albatross-instructions.html

We also posted videos showing the planes in flight: https://www.crashtesthobby.com/albatross-46-videos.html

We only cut foam, we do not sell electronics but we made a list of what to get that works and where to get the best deal on it: https://www.crashtesthobby.com/recommended-parts-list.html

There seemed to be some common problems that people reported so I made a list of things that would help them with their build: https://www.crashtesthobby.com/ten-rc-mistakes-to-avoid.html

We have other articles on our website about radios, lipo batteries, speed controls and servos, FAA regulations, and flying basics. Take a look under the RC-Info drop down on our website.

You will have more success if you get a couple of students or teachers to build a plane and learn to fly it before you start the class. Let them be the "go to" guys or gals to help the rest of the students. Let the students use our building articles and videos to help them get going.

I love to fly RC. I flew for over 5 hours yesterday on a world class slope with planes without a motor. I think one of the most important parts of RC to me is all the other flyers that I get to meet. There were about 10 advanced flyers yesterday and we all had multiple planes with us. We are just a bunch of senior men with a lot of toys but we are having fun. Many of the people who started with RC have gone on to get their pilot's license or work in the aeronautics industry. It's a good project.

I hope this helps. Keep asking questions.

Lee

Ten Radio Control Mistakes to Avoid

08/09/2026

More ramblings from Lee

I rarely break a spar and if I do it is usually such a violent hit or crash that something has to break. The fiberglass spars in an I-beam top and bottom configuration are incredibly strong. They are strong enough that even on the 78" Herc I don't think I have ever broken a spar. The Herc uses the same configuration as the Reaper. The fiberglass spars are not brittle so they tend to last better for me than the carbon spars.

I do break a few props and get a few holes punched in the wings. One of our mountain sites has rough flat ground and it tends to tear up the laminate at times but it is one of my favorite sites to fly. It is fun to fly under your feet and still have hundreds of feet to the ground. I try to land in the grass or weeds when possible. I am flying out 10-15 batteries a week even though it is hot.

I like hot glue for gluing the cores together and for gluing in the spars. The hot glue allows me to build a lot faster than any other type of glue because there isn't any cure time. It is also odorless and clean to work with. I do use the Quik Grip to glue in the shock cords. I like the Quick grip because it is odorless and cures to touch in about 2 hours. I used 3 of the 12" glue sticks to glue the spars in my current Reaper and the Bandit builds. Each glue stick weighs about 0.8 oz so I have about 2.5 oz of hot glue in each build.

Yesterday afternoon I cleaned the cores, glued the cores and then cut the spar slots and put in the wire reinforcements and glued in the spars on both on a new Grim Reaper and a new Bandit. I will get the planes taped and laminated and the elevons attached this next week. Sometimes the radio installation takes me longer than the laminating.

I have cores to replace my Titan too but my old Titan is still tearing up the sky although it looks like it has had a hard life and been attacked and patched a lot. Looking at old videos this Titan may be 13 years old. My Bandit survived 8 years of combat.

When I build I try to get the seconds cores that have defects in the surface that can't be sold. Many of the planes you see on our home page were made with these cores.

Just for fun here is a video of my Bandit from 8 years ago. This plane was just retired this month. It was one of my favorite planes. I like the long narrow wing.

I designed this plane for me. I love the long narrow wing and the ...

08/01/2026

We have always used stainless steel mounts with our flying wings at Crashtesthobby. We will continue to send them with our kits. We have updated the stainless steel design to accept more motor designs.

For at least the last 10 years we have had customers 3D printing motor mounts for our planes. Over the last few months a new group of flying wing motor mount designs have come out.

With the popularity of the new T-motors there has been a push to make it so we could use those lightweight, high power motors on our planes. Many of these are quadcopter racing motors.

Chuck is good friend and retired engineer who flys with us. He spent a many hours designing 3D printed motor mounts for many of our CTH planes. He designed the mounts so you choose your plane and print a mount then decide which motor you want to put on the plane and choose an extension with the length and bolt pattern that will fit your motor and give prop clearance with the back of the wing.

Read his information and instruction manual you can find on our website here. You can also download 35 differet mix and match options for most any motor you choose from his manual or from our website. These files are free to use.

https://www.crashtesthobby.com/3d-print-files-for-motor-mounts.html

If you have a 3D printer here are the basic program set ups we are using in printing mounts strong enough to survive the abuse that our planes are famous for. I don't think anything can be as strong as the stainless steel but here is the best group of printable designs we have seen so far.

We suggest the following printer settings: Use PETG filament with 30% to 50% triangle fill with 4 surface layers and 10 base layers where screws may be used in the mounting of the motor. You will need to add a minimal support. Use the same settings on the extensions but if they are longer extensions also use 10 top layers to help with mounting the motors. Print mounts and extensions with the motor sides down on the printing plate.

07/27/2026

We have some new products for slope and dynamic soaring.

https://www.crashtesthobby.com/crazy-horse--geronimo.html

Our 48" Crazy Horse and 60" Geronimo are high performance EPP gliders that fly well in a wide range of wind conditions. Most flyers will want to build for lighter winds for daily flight on the slopes, but the original request was to design tough EPP flying wings for dynamic soaring. These designs meet both goals. Their tapered wings pe*****te the wind well but at the same time the straight leading edge and square wing tips make them stable at slower speeds for beginner to intermediate flyers. Their flat fuselages act as extended rudders that help prevent yaw at low speeds. EPP planes are very durable and forgiving. They can take a lot of abuse. Our planes are simple and strong built with knowledge we have gained from 35 years of building and crashing EPP combat planes.

Watch the videos on the website above and pay particular attention to the flying stability and tracking in the flight videos below. They show tight turns and dives in light to moderate wind. These designs excel in predictable control and solid flight performance. They don't have the low speed tip stall tendancy I have seen in some of the other slope wings I have flown. As their speed increases it feels like they shift gears and accellerate to a higher level of performance. Both wings shown have 10 ounces per foot wing loading but have been tested at almost 20 ounces per foot. Even with light wingloading they have flown amazingly well in 40+ mph winds.

We have a world class slope 20 minutes from where I live where I have flown since the 1980s. We also have a local mountain where they are flying DS planes less than an hour from where I live. Ted flys with me on the slope but also travels to fly at high speed DS events. He asked me if we could design 48" and 60" EPP gliders capable of DS. Ted had some ideas on what these planes should look like, so if you like the way these planes look and fly you can thank Ted. For the record, I like to build light for the slope and Ted likes to build heavy for DS flying.Ted and Laurene flew the Crazy Horse at Eagle mountain and got a top speed of 155 mph which makes it one of the top contenders in the 48" foamy class.

Here is what Ted writes after building and flying the Crashtesthobby designs: "After discussing this project for several years we finally got into our testing prototypes. These new production planes take a lot of time and research. We are about one year in testing different models. Builds vary greatly but I feel Lee has nailed a great selection and has been able to incorporate several airframe choices.... I have flown slope for about 20 years and feel these are better than anything out there. Hopefully the smaller kits will be around $100 and the 60” might be around $120. I am guessing but and hopefully an achievable goal. Lee and James will have to make that call once supply chains and kit assembly costs are established. I am going to fly the rails off mine. Ted"

The first time I launched one of Ted's heavy DS planes I was sure it would go to the bottom of the mountian, but it didn't. It flew surprisingly well and surprisingly fast. The Crazy Horse build shown in the videos is at 24 ounces ready to fly. Ted has a Crazy Horse ballasted up to 48 ounces and it still flys well in 20 mph winds on the slope. The magic comes with a heavy build when the wind is 30-50+ mph and you can let her loose and she tears holes in the sky. If you are building heavy for record speeds, we recommend you add additional spars and tape and put ballast out along the wings to decrease the forces in the center of the wing in high "G" maneuvers. You need to build for the way you want to fly.

These wings have a unique but simple fiberglass spar system. The straight leading edge wing design with a square wingtip create stability and make the straight spars possible without any wing joiners which is a potential fail point in high G maneuvers. The fiberglass spars have a top and bottom I-beam style construction making the wing stiff for its weight. We prefer low temperature hot glue for almost all construction because it is simple, clean, fast and flexible and bonds well to EPP foam. Hot glue is not brittle on spars like epoxy and Gorilla Glue and bonds in seconds. Hot glue is easy to repair.

The kits come with balsa elevons at customer request. The videos show EPP elevon construction but we are now are using balsa elevons. Put one layer of clear laminate on the balsa elevon then use the same process shown in the video for EPP elevon installation. The fuselage has a symmetrical bullet shape for penitration but still has room for battery and radio and ballast. We cut the EPP foam fuselage big enough you can round it if you want.

The Crazy Horse and Geronimo kits come with 1 plane in the box including EPP wing, EPP fuselage, balsa elevons, 6 fiberglass spars, horns and pushrods, Coroplast rudder, laminate and hardware. You read correctly, The kit includes UV shielded clear laminate that doesn't need a spray adhesive!!!
​
Our laminate has a unique adhesive that is activated with a clothing or hobby iron at 180-220 F and will stick to the EPP foam. Most bidirectional reinforced tapes will stick to the EPP foam without a spray adhesive. Ultra coat and 2" packing tape requre a spray adhesive to get them to stick to EPP foam and can add 6 oz or more to the flying weight of a plane.

You will need a radio and receiver of your choice, a 3--5 amp BEC, higher torque servos for higher speeds and a 1000 mah 2S-3S battery for power and weight in the nose. Some flyers are using 4 AA or 4 AAA batteries in the nose without a BEC. I like a battery I can change out at the field so I don't ever get the the slope with a dead battery and can't fly. A lipo battery allows you to fly for hours at the slope on a single charge.

     Crash Test Hobby  "Fly More - Fix Less"

04/25/2025

We have an in state club that ordered 21 Assassins. I asked them if they would like me to come and speak at their club meeting and give them some suggestions on building and flying. I flew a finless overpowered Assassin, a standard set up Assassin with LEDs and a Scythe for the group. The wind was about 12 miles an hour but it made it fun to show off what the flying wings can do in the wind.

We discussed several things like how to laminate and hinge the elevons at the same you laminate the wing. Put a 1" strip of bidirectional tape along the hinge line and put laminate over the tip leaving enough to wrap around the back of the elevon and clear past the hinge line on the bottom of the elevon. You then do the same thing from the bottom of the wing.

Watch the hinging process on this Matador and apply the same techniques to the other flying wings. This varies from the laminating with a cool iron video also below.

[url]https://youtu.be/9yKSXZaCJb4[/url]

The same concept on the Roswell

[url]https://youtu.be/l7N5Ab2_RWU[/url]

Old method of attching the elevons:

[url]https://youtu.be/qP94aH7Zpjw[/url]

03/08/2024

Here is a basic description of the planes we sell. All of our planes are cut from EPP foam, which is a nerf like foam, and designed to be as indestructible as possible.

The Vertigo concept and name came from one of our Texas FPV racer customers who wanted more stability. This is a 100+ mph design. The Titan is the extreme version of the extended Assassin concept. The Titan is still one of my favorite combat planes. All three of these designs have a thicker high lift airfoil which is rarely seen in flying wings but the performance speaks for itself. They are great designs with fantastic performace and a lot of room for radio and electronics for their size. I still love to fly my overpowered finless Assassin. It's in a class by itself.

The Grim Reaper is a semi-symmetrical thinner wing design and was our first FPV design. It was our clubs most flown combat plane in the big combat events. It is still a very popular design because of its gentle flight characteristics and durability.

The Widowmaker was a sloper with a motor. Excellent flying plane. We now have the Matador and the Samurai slopers that are designed to fly without a motor on the slope.

The Scythe is a baby version of the Grim Reaper. It can be built under 250 gms. I have several Scythes set up for extreme aerobatics.

The Rebel Series has the symmetrical wings with a 12%, a 14% and a 16% option. We started cutting the symmetrical wings when there was a national effort to establish a racing standardized design. The symmetrical wings have also been very popular especially the Rebel S-14% because it is thick enough to stand a battery on its edge like the Assassin but is a little cleaner with less drag. The Bandit and Bullseye are our big versions of the symmetrical airfoil designs.

Technically the symmetrical wings should be able to fly faster with more stability than the semi-symmetrical airfoils but I have not seen speeds so fast that the airfoil is making that much of a difference. We have been putting the T-motors F80 on the Rebel S-14 for the 110+ mph speeds although I am aware that Bob and others line the thinner wings too.

The Roswell was the second plane we ever sold. It has a wider speed range because of the delta configuration. Originally we sold it without laminate but the builders couldn't get it to balance on the CG with the laminate. We went back and reworked the design and have the new 29" Roswell which is a great flyer.

Here is a webpage that shows a video of each of the planes.

My favorite video of each plane Many other videos available at VIDEOS link above Follow the links above to our: Building Instructions, Videos, RC-Information, Parts lists, Discounts, RC-Info and...

02/19/2024

This whole project started with us trying to find a way to mount quad motors on a flying wing. This is a T-motor F80-2200 kv motor shown on one of the strong mounts.

We also would like to get a a more versatile mount for our Roswell delta since the battery is so close to the motor that the mounting screw holes are under the battery. We think this will do the trick.

You can download the file to 3D print these motor mounts on our webpage at: https://www.crashtesthobby.com/3d-print-files-for-motor-mounts.html

02/19/2024

You can see the wedge in the angle of the mount. I hot glued a couple of these mounts to EPP foam and I can't get them off. Hot glue stick great to PLA plastic. It sticks better if you slightly rough it up a little with a soldering iron. If you want a less permanent installation you can use screws or bolts and a top plate. You can punch holes where ever you want with a soldering iron. If it doesn't fit your exact motor you can use a soldering iron to change the hole pattern or enlarge the holes for different screws.