The TufFlight Stingray
|Motor Thrust:||10.2 oz.|
|Servos:||2 GWS Naro + D|
|Battery:||E-flight 11.1V 800mAh|
|Fan Unit:||Himax fan unit|
|ESC:||Castle Creations Thunderbird 18 ESC|
|Price:||$99.00 with motor/fan unit & ESC|
A review where they want me to crash their product to show how tough it is? On purpose? I wasn't sure. My friend was a big help: "Don't worry Mike. Just treat it like any other review flight, and I'll videotape the accidents, and we will treat it like you planned to do it."
The Stingray is advertised as a ducted flying wing that can be assembled in three hours. It is a park flyer that can withstand punishment and collisions and go right back into the air. I'll cover the assembly process for the first time builder of an EPP flying wing. There are some assembly sections even I have never seen before (not difficult, just new to me). Fortunately, the instruction manual is great and has step by step instructions. I’ll also be testing the new GWS Naro + D digital servos. What better way than with the elevons (aileron and elevator mix) of the Stingray?
Items Included in Kit:
Items I supplied to complete review:
This is an EPP foam plane, and regular medium or thick CA and kicker should be used for gluing parts together. When mating two parts, spray kicker on one part, let it dry, place the CA on the other part and carefully join them together. Or apply the CA, put the parts together, spray with kicker and then wipe off any excess kicker. If you do not use kicker with EPP foam the bond will not be nearly as strong as when you use it with CA glue. USE KICKER!
Do NOT use foam safe CA also known as "odorless" CA. The foam safe CA will not make as strong a bond as regular CA. Foam safe is designed for styrofoam and depron use and not for use with EPP. Do NOT use regular thin CA as it has a tendency to run on EPP foam (messy). You will get more surface area contact on EPP foam using medium or thick CA.
Use a new Exacto knife blade! EPP cuts great with a new blade and dulls them very quickly. Start with a new blade, and if necessary, splurge and use a second new blade on the project.
When cutting out foam to fit the receiver, ESC or servos I cut the foam into a tiny grid of squares the estimated depth I will need to remove to fit the item. The little foam squares are about 1/8" square, and they remove with a side press of the Exacto knife. I don't pull out more foam or from deeper than I want, and it goes very quickly.
|Type:||Electric Ducted Fan w/ BL Motor|
|OD with Inlet Ring:||2.67"|
|Suggested Inlet Area:||1.65"-1.85"|
|Motor Thrust:||10.2 oz on 3-cell Lipoly|
|Type:||Brushless Motor Controller|
|Maximum Volts:||15 volts/Li-Po 3s|
|BEC:||3 amp max|
A thin and a thick sheet of plastic were supplied in the kit, and templates for parts are printed in the instruction manual. From the thick sheet of plastic I cut out two elevon control horns after drilling a hole for the control rod to connect to. From the thinner sheet of plastic, I scored and cut out a battery tray cover and four parts used to join the wings and mount the ducted fan unit. I simply followed the instructions and used a new Exacto blade.
The heart of the Stingray is the well-proven Himax electric ducted fan with brushless motor. These came with the Stingray kit along with the Castle Creations Thunderbird 18A brushless ESC. With the right weight 3-cell Lipoly battery pack, this combination will provide the Stingray with a better then 1 to 1 power to weight ratio, and that means a speedy little plane with its 31.5 inch wingspan. The motor came assembled in the fan unit, but after that the instructions took me by surprise: There was a plastic flange on the fan unit, and per the instructions I used a pair of pliers and twisted off the flange and then cleaned up the flange line with my Exacto knife. The fan ring was glued onto the front of the unit with CA and kicker per the instructions.
I assumed I would be adding the included connectors to the ESC that would match those on the motor but I was wrong. I used my soldering iron to remove the connectors from the motor. I cut the ESC wires very short and staggered as per the instructions and cut the battery connecting wires very short as well as shown on a template in the instructions. I then soldered the parts together to remove unnecessary wire and weight.
I installed the correct servo arm onto my GWS Naro+D digital servos and plugged them into the receiver, and I set up my JR 9303 transmitter for a Delta wing that would properly work the elevons.
GWS Naro + D Digital Servo
|Operating Speed||(4.8V): 0.16 sec/60°|
|Stall Torque (4.8V):||(4.8V) 22 oz-in.|
|Dimensions:||0.87" x 0.43"x 0.96"|
|Connector Wire Length:||5"|
|Gear Type:||All Nylon|
|Operating Voltage:||4.8-6.0 Volts|
The wing assembly was very well described in the manual, and I was taken through it step by step. The first step was the removal of cutting residue (called “spiders”), a normal part of the cutting of the EPP foam wing. these are called spiders and they are a normal part of cutting a foam wing. I cut a slice in the wing’s root for the plastic insert I made at the start of the project. I then cut into the wing a 1/2 inch on the leading edge and side tip of the wing to insert a supplied Kevlar thread. Once the thread was inserted, I glued closed the cuts in the foam with medium thick CA and kicker (I used an old credit card to spread the glue inside the sliced foam).
I cut out the spaces in the wing for the servos, receiver, ESC by following the step by step illustrated instructions and my tips numbers 3 + 4 above. The foam rectangles where the servo arms will go through are cut out completely. For the body of the servos, receiver and ESC, the cut in the foam is only deep enough to fit the components. The electronics are only trial fitted in this stage and will be installed later.
With both wing halves properly cut and fitted for the radio gear they are set aside, and the motor/fan unit is installed into the center section of the wing. The opening at the top of the ducted center section was glued closed. Kicker first sprayed on one side of the joining seam and allowed to dry, but the other side of the foam seam was covered with plastic wrap to keep it from getting any kicker on it. I spread thick CA on the other side of the seam, then brought the two sides together and held them. I made a two inch slit was made in the left side of the center section at the bottom of the wing mounting area. The wire from the motor to the ESC was slid into this slit, and the wire was pulled back while the motor fan was inserted. The foam slit was glued closed, and the rim of the motor was glued to the front of the center section.
TufFlight recommends using a Thunder Power 3-cell 910 mAh battery pack with JST connector and 13 A continuous current capability. I used a 3-cell E-flite 800 mAh pack with JST connector. It is only a 12 A continuous current pack. By using the E-flite pack, I was giving up a bit at the top end and a little over 10% of the maximum duration if I used the recommended Thunder Power pack.
At this point the carbon fiber spar was glued to the center section, the wing panels were glued to the center section and then the spar per the instructions. The electric components were wired together, and the wire was stuffed into slits cut in the foam. The servos were glued in place while the receiver and ESC were secured with covering tape glued in place. Connector rods were shaped out of wire supplied and connected to the installed elevon control horns cut out of plastic. Supplied EZ style connectors were installed onto the servo arms for the wire rods with Z-bends going into the control horns on the elevons. Controls were checked using the radio. I followed the instructions and glued the vertical stabilizer onto the top center section.
Consider using "Quick Grip" glue instead of CA for repairs and some assembly steps where front end collisions happen. It is like rubber cement and dries flexible. Quick Grip is thin, easy to apply and doesn't cost much. We find it at Walmart. I used "Plasti Dip" in the spray paint can to paint 3 coats onto the front points of the Stingray just past where the front of the fan meets the wings. (don't paint the whole plane!) It makes a nice "skin" that holds up great for crashes. Plasti Dip is available at Home Depot in many colors including white.
My local Home Depot only had the red color Plasti Dip you see on my plane in the pictures below. I used spray-on Plasti Dip and put three coats on the Stingray's leading edge to help protect it. The weight of it on the front helped me obtain the recommend CG on the Spar. 60% exponential was used on the aileron controls and 30% for the elevator control. This made the wing with its elevons a little easier to control with slight movements, but left full throw with full movement of the controls if desired.
Center of Gravity was located on the spar per the instructions, and that was easy to find.
Full throws with elevons can be a bit much for my taste.
The plane has a nice speed range and remains very controllable even at slow speed. But hit the throttle, and it picks up its speed quite nicely. I throttle back and fly around the field slowly with a slightly up nose position. Because of its small size I can convince some people that it is a slow little wing without saying a thing. Then when it comes around for the third time and is right in front of us, I hit full throttle and do a vertical climb and then some wing acrobatics. With the controls toned down it was a very gentle flyer with the ability to go wild at full throws and throttle.
All takeoffs begin with a toss and all landings end with a slide. Having a nice grassy surface to land on is a big plus when flying the Stingray. There is no propeller at the back of the trailing edge to watch out for when hand launching the plane. A good level toss forward was needed to get the ducted fan off to a good start to getting the plane up to speed but only a good toss was required - nothing hard or strenuous. I found it easy to launch and land.
It is capable of doing all tricks expected from a flying wing including loops, split Ss, vertical stalls with sloppy backward slides and of course nice quick axial rolls. The Stingray is a nice plane to take to the slope. On days with no wind it can be flown normally as an electric ducted fan, but on days with even very little lift it can slope due to its lightness. If the wind dies for a period as it often does on light breeze days, the motor can be activated and the plane powered back up the hill avoiding the walk of shame. If there is more then one Stingray present (or other EPP plane) then combat can be entered into by the pilots with very little chance of damage.
Since crashing is "just another maneuver" I did go out and intentionally crash the Stingray. After a crash into a fence I finally did a little bit of damage. I split the foam open on the two front points where I had sliced it in the assembly stage to insert the thread. One piece of the foam on one side of this split broke open. I performed repairs in less then a minute with CA and kicker. A follow up touch of paint and it was as good as new. It should be fun to do a little combat with several of these. The ducted fan is protected pretty well from any damage.
This wing has certainly proven itself durable, and while that is a great feature for a beginner plane it has no self recovery capability. Let off the controls, and the plane goes where it was last pointed and at full throttle does so rather quickly. While with its elevons and durability it could make a good "aileron' trainer for a pilot who has mastered the basics I would not recommend it as a beginner's plane.
The two servos have performed great thus far and have held up to some intentional strikes of the plane to the ground, a tree, a baseball backstop fence and a couple of other things. I expect they will continue to perform well but will report if any problems develop. The servos are reasonably priced, perform well and control the elevons very well with no chatter. In fact, they take a licking but haven't started clicking. I am very happy with them and will be using some more in future projects.
Having assembled and flown several hundred RC planes and a number of wings it is unusual for me to come across as many "new to me" building features as I found in this plane. But thanks to the excellent illustrated instructions everything was easily understood before I started. The plane is very responsive and a little Exponential as discussed above improved the handling quite a bit.
Flat pass speed full out is only moderate, not fast. It will slow down to a crawl and goes fast enough in a full throttle dive but not fast. Does a nice roll at 3/4s throttle and higher. At slow speed and climbing it does a half roll, balks and then continues with the roll. Never seen anything like it. Tight spaces, combat, slope on a poor wind day are where mine will get most of its flying time. Once mine was trimmed out it was a lot of fun. I have to watch where i set it down or what I put on it as I can temporarily bend the elevons. They went back to the original shape in a couple of hours but made for a Mr. Toad wild ride for one battery pack. Mike H
PS: I'm great at estimating how high a plane is but speed not so great. We are guessing top speed about 30 in a flat pass without a dive. I just need someone to get one for combat.
GREAT review!! This thing looks sweet on the table, but even sweeter in the air If I get one, I'm comming out to play combat
Um, I thought cutting the ESC wires short was a bad thing to do. Everyone has told me to not cut the wires to the motor, only going to the battery
I flew it after church today and this thing is growing on me. Will fly it again tomorrow morning with some friends. I may save it for late morning and see if I can thermal this thing with the motor off. Mike
PS: 54 miles per hour? Well I said I am not so good at estimating speed.
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