The Uproar Review

Anyone who has been a Spirits member for more than a year knows about the infamous “4-Star Forty” by Sig Manufacturing and its functionality as a pylon racing plane in our club. Last year, 4-Star’s were impossible to get thanks to shortages of balsa and other issues. Hence, several of us were looking for cheap and available options. Thus, the Uproar. Details on where to purchase etc were already discussed in this previous blog post.

The Tower Hobbies Kit:

I think it was literally 20minutes between when I ordered it and when the front doorbell rang. I love buying things from Tower. I get free delivery and it shows up in a few days. I ordered two of them and it was obvious that is how Tower gets them from the manufacturer because they were boxed together. I purchased two glow engines as well and they were packaged separate. I opened everything and all the parts were isolated appropriately and secured in cardboard (no foam which I like). The kit comes with everything you need to fly except an engine, fuel tubing, servo’s, receiver, and your choice of battery.

My Components:

Engine: O.S. 46AXII ABL
Servo’s: (5) MKS HV69’s Micro’s for Ailerons, Rudder, Elevator, Throttle. I 3D printed adapters since the kit is for Mini servos.
BEC: Castle BEC if you run low voltage servos. I can just plug a 2S Lipo in my receiver since everything is HV.
Fuel Line: Sullivan Silicone
Fuel: 15% Nitro Cool Power by Morgan Fuels
Paint: Dubro Lexan Paint for the canopy.
Covering: A combination of Monokote and Ultracote I had ordered previously (Carbon Fiber, Orange)
Graphix: B&E Graphix provided me with the numbers and lettering for the plane.

Use a BEC to regulate down to 5 V and install any LIPO that you want!


The planes went together very simply. If your a skilled balsa ARF builder then your in great shape. If you have never built one your still in great shape. This thing is simple. I didn’t use the instructions until I needed the landing gear template to show where to drill the pilot holes for the 8 fasteners and when I wanted the recommended CG and Controls Surface Throws.

I recommend adding some bling to the thing with some different monokote racing stripes, Flames, colors, etc. I chose to remove the covering where I changed the colors just to keep weight down. The graphix were from B&E using their lettering generator. The power tip there is to combine graphics together. For example, instead of creating a separate “Ralph” and a separate “Dustin”, create a “Ralph Dustin” and its cheaper than an individual graphic. For example the numbers were “28 28 17 17”

A pair of Uproars! I painted the canopy’s so I didn’t have to put a pilot in there to save weight.

I went with Micro-Servos in one of the planes which caused some minor issues since the plane is designed for mini’s. Nothing that the 3D printer won’t solve. So I designed some adapters in AutoCAD Fusion and printed them on the Prusa 3D printer. I added some flames to the adapters to make them look awesome!

I CG’d her exactly at the 3.25″ from leading edge recommendation and it was great. The plane gives you some great hatches on the top front so you can look at your fuel tank when filling and on the bottom to change out your receiver battery and check servo connections and attach the wing bolts. I velcro’d my battery under the wing tube and it CG’d perfect with the micro servo’s.

Glow Motor Break-In:

I broke in both motors together on a simple stand that I created out of two pieces of Poplar I had on the wood rack. I just cut two 18″ boards and screwed them into a 90degree at the long edge and attached the motor mounts to it with a fuel tank and throttle rod to the carbs. Took them to the field an ran them in. I opened the throttle completely and screwed the High Speed carb needle out until it was four stroking at about 2000 RPM and ran two tanks through it. On the 3rd and 4th tank I would screw in the needle and let her max out for a few seconds and then out till she slowed down.

On the 5th tank I screwed the high speed needle in until she maxed out RPM’s and then closed the throttle down until she idled. I then would open the throttle as fast as I could and see the transition. If she bogs down I lean out the low speed adjustment screw. If she dies I richen it up. I did that until I got a smooth transition from idle to high speed with great response. I then checked the high speed and leaned it out until it maxed out in RPM’s and started to slow down and then richened it up about a half a turn and left it there.

Maiden / First Flights:

The day I picked for maiden couldn’t have been better. A nice Saturday morning with about 8mph wind right down the runway, sunny, and about 80F. I fueled the uproar up with 15% Cool Power (The fuel I used to break it in), placed the ignitor on the glow plug, and hit it with the starter. BOOM. The freakin’ spinner nut came off and flew into the grass. Jeez. I put it on again and tightened it down with the Spinner Nut Hardened Rod that came with it and hit it with the starter. BOOM. The spinner nut came off again.

Race #28. Ralphs Uproar!

I grabbed a longer Allen Driver from my tool bag and tightened the spinner nut as tight as humanly possible. This time, when I hit it with the starter she purred like a kitten. I ran her up a few times, checked the high speed needle setting to make sure she wasn’t too lean, and carried her over to the taxi-way. I taxied her over to the runway, advanced the throttle, and she was airborn! Two clicks of right aileron and 2 – 4 clicks of up and she was rocking. I immediately dove to the east pylon, rolled her over on her side, and yanked back on the elevator. Vrooom! You can hear the drag over the big fat airfoil when its going across show center. When she got to the west pylon I rolled her on her side, and yanked back on the elevator. Vroom. The 50% Expo was perfect and mid-rates yielded a plan that corners like its on rails but was kinda twitchy in the ailerons. I got about 5-1/2 minutes out of the 6oz tank the Uproar came with and still had about 10% left in the tank when I landed. Before the next flight, I dialed in a little more elevator and a little less aileron and on the next flight she was perfect!

In Summary:

Its been at least 20 years since I had a .40 size glow plane. I didn’t realize how much I missed it until I built and maidened this. For some reason, I always remembered glow engines to be a finicky pain in the ass. This was far from that. I’m sure I’m just a little more patient with the few grey hairs I’ve obtained and I’ve learned a little more about tuning carbs / needles from my gas engines, not to mention the modern engines are probably just better with the latest lean and high quality manufacturing techniques. Either way, I’ve already begun getting my old Saito 80 cleaned up and am planning on getting a few of my other glow engines back in the air. I think its time the SuperTigre GS51’s come out of retirement. I had originally planned on converting them all to electric but to be honest, putting a little glow fuel in the tank, putting the ignitor on the glow plug, and hitting it with the starter is easier than messing with batteries, charging stuff, etc. I have a new love for the glow engines that I learned to fly with and am looking forward to getting some of the older legacy birds back in the air after a little engine and fuel system maintenance. Stay tuned for the Ultimate Bipe, the Gee Bee Model 12Y, the Super Sportster, the GS40 Four Star, and a few other birds to make their return!

If you have been avoiding glow engines or have been away from them for a while, I highly suggest you give it another try. As for the Uproar, she’s no beauty queen but she sure flies nicely. We’ll see how she fairs at the races this weekend!

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