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Tower Uproar ARF Returning to Glow with an OS 46LA

Jim Walker, having enjoyed this Tower Uproar as an electric but encountered gear box problems, now brings her back off the shelf, returns her to glow power and enjoys her smoking performance!

Splash

Introduction


Wingspan:48"
Wing Area:618 sq. in.
Weight:66.75 oz.
Length:44"
Wing Loading:15.56 oz/sq. ft.
Servos:5 Hobbico C-60 Standard
Transmitter:Hitec Eclipse 7
Receiver:JR R700
Battery:5 cell 1000mah Nimh receiver pack
Engine:OS LA .46
Prop:APC 12.25 X 3.75
Manufacturer/Available From:Tower Hobbies

I originally reviewed this plane as an electric conversion. The airframe performed wonderfully, but there were problems with the motor and gearbox and consequently the Uproar saw a lot of shelf time. If you haven't already read it, you may enjoy reading the electric conversion article for the full story. (For those who may be interested, Feigao did eventually resolve the problems with their products and I did some static and flight testing on new samples sent to me. The positive results are documented in a second article as well.)

The Uproar is such a great plane I just couldn't let it sit, so I decided a comparison and follow up article was in order. I guess I was holding my eyes right or something because the next day, right here on RCGroups, a member was letting an OS LA .46 go for a very reasonable price. (The uproar was designed around .32-.40 sized engines, with a 2-stroke .46 being the maximum recommended power.) I jumped all over it and the result is this article documenting the "re-conversion" of the airframe back to the glow power for which it was originally designed.

Re-Assembly

I'll just say again what I did in the original article, which is that the instructions for this ARF are first rate, so there's no point in repeating them here. As for the reconversion, I dug out and dusted off the original, included motor mount and gas tank and then proceeded to put everything back to as close to original as possible.

The only difference in the radio setup between the original electric conversion and returning to gas power was adding the extra throttle servo and creating the linkage.

Of note was that even using the largest recommended engine for this plane, I still was only 2.75 oz over the maximum listed weight and the total all up electric ready weight. I firmly believe that the extra 2.75 oz. here were the result of the electric conversion and then re-conversion back to glow. If one were to build the Uproar for glow power from the start, the total weight with the OS LA .46 would easily be at or under the advertised max weight of 4 pounds.

Also, getting the CG correct with this larger engine was no problem at all. After completing the re-conversion, I put the Uproar on my CG machine and then moved the receiver pack around to balance. I feared that I was going to have to put it wayyy back in the tail, but it turned out that placing it under the servo tray was all that was needed!

Comparison: Glow vs. Electric

The first thing that I really wanted to know was how many more RPM's, if any, I would gain with the glow power. As soon as the Uproar was re-converted, I took it out front with the tachometer. Once I had the engine dialed in, I checked the RPM with two props that were of the same diameter and pitch as the electric version. First up was an MAS 11-7 which was the recommended prop for sport flying with this engine. It rendered a respectable 10,200 RPM. In comparison I had used an APC 11-7 on the electric Uproar to achieve not quite 8000 RPM. Next I tested a MAS 12-6 scimitar prop and still achieved 9800 RPM. The APC 12-6 on the electric setup had been approximately 7500 RPM. No doubt, that much of an RPM gain had to make a big difference!

Prop Comparison RPMs
Prop Size Electric Glow
11x7 8000 10200
12x6 7500 9800

During test flights I tried other props and needle settings until I finally settled on the APC 12.25 X 3.75. If you haven't tried this prop on fun fly planes of this type or 3D planes, I suggest you do! It keeps the thrust coming, no matter what the air speed. This was just what was needed for fun fly planes like the Uproar that have low aspect ratio wings with extra thick airfoils. Once I switched to this prop many good things happened, including the engine transitioning from any partial throttle position to full throttle much more smoothly. This was regardless of what the Uproar might be doing at the time. Another bonus was that I gained several hundred RPM.

When It Comes to a Sport Plane, It's All About Cost

Bottom line... There's no doubt that I could have achieved similar or possibly even better performance with electric equipment..much more expensive electric equipment. The real issue, in my opinion, is money. Perhaps in the future electric prices will come down enough to make this argument void. But, for now at least, this project proved to me without a doubt that outstanding performance can be achieved with considerably less funds by using glow power. On future projects of .40 size or larger, wet power is going to be my choice simply for financial reasons. Remember, this is coming from a flyer that was recently all electric!

Flying

Well the big day arrived, and I took the re-converted Uproar to the local field for some trials. Since I had previously test run and tweaked out the OS LA .46, it fired right up with no excuses. Even though I had a lot of confidence in the airframe, I was still a little nervous about this second maiden flight. I need not have worried. The Uproar jumped right into the air without hesitation after I advanced the throttle.

Just a few clicks of down got me close to neutral stability. Since I've taken up 3D flying, I no longer trim for upright hands off flight. Instead I look for neutral stability either upright or inverted. Few planes are actually truly neutral either way, but the Uproar was very close, with only very slight pressure required to maintain level flight in any attitude. Now that I had everything dialed in, it was time to push the envelope.

Loops were as tight or as big and high as desired. Not only could I do giant loops, now the Uproar had enough power to do giant square loops! Inverted loops were nearly identical with no tendency to roll out. Rolls with the big ailerons were lightning fast no matter flying horizontal or vertical.

The Uproar did start dropping it's nose during rolling maneuvers, but just a touch of up and down elevator at the right times made rolling from horizon to horizon a snap. Snap rolls with the rudder were good, but even more impressive was a maneuver I call "Axial Continuous Snap Rolls". I tried it on my simulator with a similar plane to the Uproar and then tried it in real life. Sure enough the Uproar pulled it off identically! Basically, the nose stays in one spot on an axis moving forward while simultaneously the wings roll and the tail corkscrews. The first time I did it at the field all the guys were scratching their heads and asking, "What in the heck was that??" Be sure to catch this maneuver in the video section.

Slow speed flight with the low pitch prop and super thick airfoil was awesome, and nearly in the 3D category. I could do semi-harriers with confidence. Stall turns were awesome with the Uproar climbing vertical and then rotating around its axis perfectly with just a blip of the motor to get it started rotating. Spins were acceptable but I was unable to achieve a flat spin. As the nose would come up the rudder just wasn't effective enough to keep the tail rotating around the CG.

This brings me to the only "down" check for the flight envelope of the Uproar, one that has been mentioned by others as well. Even though the rudder is huge on the Uproar, it just wasn't very effective. Attempted knife edges just resulted in rapid and scary descents! While it has a large rudder, there isn't much side area on the fuselage, and so there simply is not good rudder authority, regardless the throws or servo power applied.

As for ground handling, the rudder and steerable tail wheel provided exceptional control. If the stick was hammered to full throttle on takeoff the Uproar took off in a ridiculously short amount of space. Landings were almost as short with the Uproar's great slow speed flight characteristics. On approach the Uproar was able to just gradually nose up and apply throttle to slow down to a crawl. Then just before touch down, I released the elevator and chopped the throttle for a greased landing. In a headwind close to zero speed landings were possible! Last but not least I tested dead stick landings. They were a non-event, keeping the nose level was all that was required. There was plenty of time to pick a landing spot and one could hardly tell that the engine had died, in fact. Most times I even rolled it up close and didn't have to make the walk of shame!

There were a few differences I noticed during flight trials after the re-conversion. First and most evident was the speed envelope. The extra RPM's and thrust from the .46 OS LA/APC 12.25 X 3.75 combo allowed me to pitch the nose of the Uproar even higher than before for super slow speed. At the other end of the spectrum with the throttle wide open the Uproar could really move out! Duration was also changed for the better. With the stock tank included in the kit I have yet to run out of gas before I'm ready to land. I estimate 20 - 25 minutes on a tank of glow fuel!

Flight Video

Downloads

Conclusion

The Tower Uproar ARF is simply a great airframe, no matter what the power plant. For a very reasonable price you get a well built, high quality plane that's easy to assemble. With mild throws the Uproar has great manners for the intermediate pilot. Turn up the throws for the advanced flier and the Uproar can do just about anything except 3D. Get yours today!

Discussion

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Old Sep 18, 2006, 04:33 PM
I'll try anything once!
thacherd's Avatar
Huron, South Dakota
Joined Jan 2004
1,088 Posts
I recenty purchased an Uproar ARF and I must say that the quality of the plane is first class. The parts came out of the box in perfect condition... no need to tighten loose coveing. The ease of assembly is top notch. There are some details in the manual that are outdated, but it is in the assembler's favor. (The notches in the control surfaces are pre-drilled and pre-cut, which the manual says that the assembler has to do) Very nice ARF. I hope it flies equally as well as the quality I saw in the assembly process.
Thanks for the review and the photos.
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Old Sep 19, 2006, 08:23 AM
Use The Force Jim
Jim Walker's Avatar
Las Cruces, NM USA
Joined Jul 2001
2,341 Posts
I'm glad you enjoyed the article Thacherd. I definitely agree this ARF is top notch in every respect. I'm sure you'll enjoy flying it with whatever power plant you've chosen as much as assembling it.

Enjoy!

Jim
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