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Old Dec 13, 2011, 12:38 AM
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Gopher huntin' stick jockey
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United States, MN, Minneapolis
Joined Jul 2009
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Mini-Review
UMX Beast 3D - first impressions & maiden video

Hi all,

Of course, I just had to add one of these to the hangar! I got the maiden in, and a couple flights on the 5043, as well!

However, my hatcam battery must be on its way out. It crapped-out during the second video - which was with the 5043 on my homebrew Hyp 180 & 240 packs. Fortunately, I did get the maiden. Unfortunately, the second file got corrupted when the battery died, so I don't have any video with the 5043. Bummer, as I was flying much more aggressively during the second & third flights. I ran out of light before I could try the 5030. I'll shoot some more footage with the 5030 & 5043 when I get a chance.

Flight-report:


Elevation: 930' AMSL
Temperature: +40 F
Wind: 2-4 MPH
Maiden

UMX Beast 3D
Stock prop & throws
Homebrew Hyperion 180 mAh 2s pack
EW: 57.18g
AUW: 69.0g
Tx settings:
ATV: +/-100%
Rates: 100%
Expo: 0%

I took the plane out of the box, popped in a Hyp 180 2s pack (front of the pack just behind the cowl opening), bound it to my Futaba 10CHP, and checked for any gross misalignment. Finding none, I fired up the AS3X by blipping the throttle. I rotated the plane about its three axes of rotation, and checked for the expected control movements. Everything looked good, so I headed to the runway. It was nearly dead-calm. I thought it a bit ironic, as this was the first time I've actually wished for some wind during a maiden flight!

Takeoff & climbout:

On taxi, it was quite apparent that something was different. The plane taxied straight as an arrow hands-off! A strange feeling to those of us who fly the V1 (or any short-coupled taildragger).

I lined up & rolled into the throttle. By the time I reached half-throttle, the Beast was airborne. First thing I noticed was that the aileron trim was way off. I added quite a few clicks of right-aileron trim to compensate. Apparently, I should have checked the mechanical alignment more carefully!

The AS3X system definitely helps to keep things straight on takeoff. While shooting touch & gos, I abruptly nailed the throttle to see what would happen. I watched the rudder go hard-over to the right as the system compensated for the sudden change in torque. The tail wagged slightly, but the plane kept going straight down the runway.

After getting the trims sorted out, I worked on assessing the basic performance of the plane.

General flying characteristics:


As compared to the V1, the Beast 3D flies much more smoothly. The plane definitely goes where you point it. It tracks so well that it's sort of uncanny. Flying 'big' with the 3D looks even bigger than it does with the V1. CG changes still require a bit of elevator trim change. I did notice a few idiosyncrasies, however. First off, bank & yank turns just don't 'look right'. (Not that they ever really look right to me with any plane; rather that they look even 'less right' with the Beast 3D.) I tried a 'bush-pilot-style' forward-slip landing. The AS3X definitely got in the way during that maneuver. The plane did not behave as I expected it to. I can't quite describe what it did, but it was not natural. It's possible that I was trying to compensate for something the system was already taking care of. I'll have to work on a new technique for forward & side-slips.

The Beast 3D's nose pretty much stays put - regardless of throttle setting or airspeed. So does the bank-angle. I did not think to investigate the system's performance during a level power-off stall. I'll have to do that next time.

Landings:

The original Beast is a pussycat on landing, provided the pilot remembers to control speed with elevator and descent-rate with throttle. The Beast 3D is even better. Approaches are silky-smooth, and the plane just wants to do a 3-pointer. As much as I love shooting touch & gos with the V1, I find them even more enjoyable with the 3D.

Performance with the stock prop:

As others have noted, the Beast 3D's thrust-to-weight is lower than the V1 when both are flown with the stock prop & a Hyperion 180 2s pack. This was readily apparent to me, as well. With a lightweight Hyp 180, the plane can easily pull vertically out of a hover - albeit not with authority. However, vertical performance is still adequate for unlimited aerobatics. I had no trouble corkscrewing the plane into the sky until it was difficult to maintain orientation - and that was near the end of the pack. That said - I definitely prefer more speed on up-lines, and I wouldn't mind a bit more thrust. But then I fly more scale/pattern aerobatics than 3D.

In the video below, a 6:30 flight pulled 157 mAh from a Hyp 180 pack. That's 87% discharged! I won't do that again! 80% discharge would have been ~6 min.

Second & third flights

UMX Beast 3D
Stock throws
GWS 5043 prop
EW: 57.0g
Homebrew Hyperion 180 mAh 2s pack
AUW: 68.8g
Homebrew Hyperion 240 mAh 2s pack
AUW: 71.8g

Performance with the GWS 5043 prop:

My second flight was with the 5043 & Hyp 180 pack. I also moved the CG slightly aft. I noticed a definite improvement in level speed, roll-rate, and initial climb-rate. However, the speed tended to fall off considerably during long up-lines.

For the third flight, I switched to a homebrew Hyp 240 2s pack. I immediately noticed a marked improvement in sustained vertical performance, as well as level speed. Roll-rate on up-lines was very much improved, and I could do a vertical rolling climb until the plane was just a dot in the sky. Still, vertical speed seemed to be just shy of my V1 on the same prop & pack.

With the Hyp 240, a 5:30 flight used 166 mAh, or 69%. That's ~30.2 mAh per minute. With the Hyp 240, that would be ~6:20 to 80% discharge. However, that would be just 4:45 to 80% discharge with a Hyp 180 pack.

Aerobatics:


The Beast 3D tracks through basic maneuvers such as loops and rolls with surgical precision. It feels surreal to me. Similar to how a perfectly-trimmed pattern ship feels. It's much easier to hold a good up-line, however some correction is still required. I could repeatedly hold good up-lines for much longer than I have ever done with my V1 Beast.

Inverted flight required no elevator input at all. I felt like I was more aware of the AS3X system when flying inverted - likely because the plane flew exactly the same as it did when flying upright! Again, sort of surreal.

KE flight is "so easy, a caveman could do it". Just a bit of top-rudder was required for level KE flight. The plane feels uncannily uncoupled during KE. This is a good thing, although it feels a bit strange at first. I'm thinking that KE loops will be much easier with the 3D than the V1. I didn't try one though, as the visibility wasn't very good.

Snaps don't seem to be very 'snappy', although they stop immediately when the sticks are released. Moving the CG aft & increasing aileron throw should liven things up.

Conventional spins seemed to feel about the same as they do with the V1 - that is, until I tried an inverted flat-spin. I could definitely 'feel' the AS3X. When I neutralized the ailerons, the nose leveled-out immediately, and the plane settled into what appeared to be a slow-rotation inverted flat-spin. But I'm not sure if the plane was flat-spinning or just doing very tight flat-turns. Again, moving the CG aft should help.

Hovering seems to be a bit easier with the 3D than it is with the V1 - but it is far from easy. An aft CG helps. Torque-rolls are a different story! The AS3X makes it much easier to do great-looking torque-rolls. I even managed a torque-rolling tailslide and then transitioned into a torque-rolling climb - something I have never been able to do with the V1.

High-alpha is also easier, as there is much less wing-rock. It's still CG-sensitive, though. Move the CG forward a bit to far, and there is a fair amount of wing-rock - less than what there would be with the V1, but it's still there. Move the CG aft a bit, and the wing-rock all but disappears.

AS3X - first impressions:

The Beast 3D definitely feels much bigger than the V1, and it does fly as if on rails. In some ways, it 'feels' more like a 40 or 60-size plane. In other ways, it feels more like a larger version of the V1 Beast. For instance - when flying scale, pattern, or IMAC-style maneuvers, the 3D feels very big. However, when hovering or torque-rolling, it feels more like a larger version of the V1. The moments seem much larger than the scale suggests until the plane breaks out of the hover or torque-roll. When it breaks, it breaks quickly - more like the 2-oz plane that it is. But unlike the V1, it doesn't give any warning. Of course, a damping system cannot make a plane feel bigger when there is no air over the control surfaces - as has been discussed.

The AS3X system does not turn the Beast into an aileron trainer or aerobatic trainer. The Beast 3D won't replace a 3-ch trainer, aileron trainer, or even an aerobatic trainer. There is still no free lunch.

If it would have been windy, I could have provided a more in-depth assessment of the system's capabilities.

Conclusion:


One thing is certain - AS3X will not compensate for a lack of skill! It will make maneuvers look more fluid & polished - as if they're being performed with a larger, well-trimmed pattern ship. But the pilot still has to fly the aircraft, and must know how to do the maneuvers. Those who are used to flying planes with throttle/pitch-coupling and self-righting tendencies will have a very steep learning curve if they decide to go directly to the Beast 3D - especially if they don't have any sim-time on unlimited aerobatic planes.

The Beast 3D definitely flies big - even when there's no wind. I find it considerably easier to fly smooth maneuvers with it - as compared to the V1. With the stock prop & a Hyp 180 2s pack, I find the plane to have adequate thrust, but speed is lacking for my flying style. A 5043 & Hyp 180 pack will provide a noticeable improvement in level speed, but the Hyp 180 pack seems to be overtaxed a bit - especially on up-lines. I noticed a significant improvement in sustained vertical performance with the heavier Hyp 240 2s pack.

Flying the Beast 3D definitely feels different than flying the Beast V1. Flying through the AS3X has a different feel than flying the plane directly. Some pilots may call it robotic or sim-like - just as some pilots thought early flybarless systems felt robotic or sim-like. After 28 years of flying direct-control, it will take some time for me to get used to flying through the system. I definitely need more than 15 minutes of stick-time to give a fair impression of what I think. I also need to fully explore its aerobatic behavior & fly it in some wind. So far, I like the new system, but it has a few idiosyncrasies during certain maneuvers that I need to work out.

The Beast 3D needs really good batteries - even more so than the Sbach & V1 Beast. Those who use low-C packs, cheap packs, or a series harness will experience significantly reduced performance. They will not see an improvement by switching to the 5043 unless they build or buy some high-quality 2s packs.

It was too dark to get static RPM data, as optical tachs require natural light. Household lighting systems corrupt the readings. I'll probably have to wait until the weekend to do the static RPM tests.

Here's the maiden. It's not one of my better videos, however:

EFlite UMX Beast 3D Maiden (9 min 16 sec)


EDIT 12/13/11:

I went back to the field today to re-shoot the 5043 videos. Cam was fully-charged when I left, but it crapped-out again. I managed to get some footage with the 5043 & Hyp 180 pack, but the cam died & dumped the file while I was shooting the Hyp 240 flight. Cam only runs for about 7-8 minutes on a charge. It used to run for 30 min or more. Looks like the battery is completely shot.

Here's the video with the 5043 & Hyp 180 pack. Definitely a noticeable improvement in vertical over the stock prop on the same pack. There was a bit of a breeze this time, but the Beast didn't care. Of course, you still have to fly the crosswind, but the bobbing & darting is gone. The plane feels really big in a light breeze. The wind was 90 deg, to the runway, so crosswind landings were in order.

Elevation: 930' AMSL
Temperature: +37 F
Wind: 3-7 MPH

UMX Beast 3D
Throws: Stock
Prop: GWS 5043
Pack: Homebrew Hyperion 180 mAh 2s

Beast 3D - GWS 5043 + hombrew Hyperion 180 mAh 2s pack (7 min 39 sec)


Since the cam was dead, I decided to just fly around & get used to the system. I figured out what was up with the KE yesterday. It was an aft CG problem. AS3X definitely masks most undesirable effects of an aft CG - however, you still have to trim for level flight. So, if the plane is nose or tail-heavy, you'll still get pitch-coupling in KE. After the cam died, I flew a few Hyp 240 packs and played with the CG a bit. It appears that the Beast 3D's natural balance is aft of the V1. So, when I put my packs in the same location as I would in my V1, the 3D was actually tail-heavy, rather than neutral. For a neutral CG, the front of my homebrew Hyp 240 packs ended up just about flush with the cowl opening. That's about 8mm forward of where the same packs end up in my V1 Beast. See the attached pic.

I figured out how to get the Beast to do a bank & yank turn. Just bank & yank- don't touch the rudder at all!

I managed to get some static RPM data on the 5030 & 5043 before it got too dark for my optical tach. As usual, each reading was taken under natural light - 30 seconds into the run on a freshly-charged pack. See below:

Elevation: 910 ft AMSL
Temp: 70 F

----------- Hyp 180 --- Hyp 240 - Thrust (g)* - Speed (MPH)**

GWS 5030 - 10,740 ---- 10,780 -- 112/113 ------ 30.5/30.6
GWS 5043 -- 8.400 ----- 8,880 ---- 96/108 ----- 32.2/36.1

*From the GWS props spreadsheet
**Calculated pitch-speed. Slippage & in-flight unloading not taken into account.

Joel
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Last edited by turboparker; Dec 13, 2011 at 06:12 PM. Reason: Added video, flight impressions, and static RPM data
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