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Old Sep 03, 2012, 01:47 AM
R2R
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St Johns, FL, USA
Joined Nov 2009
653 Posts
Mini-Review
Bird of Time ... ARF

Model
Name: Bird of Time ARF
Mfg: Great Planes-Dynaflite
Span: 118"
Controls: Rudder, Elevator
All Up Weight: 67.5 ounces
Price: $169.99 online
Battery: 1500mah 5-cell nimh
Receiver: Airtronics RX700 (fhss-1, 2.4 GHz)
Elevator servo: Hitec hs-65HB
Rudder servo: Hitec hs-325HB
Transmitter: Airtronics SD-10G
Hi-Start used: 100 feet of NSP Pinnacle Standard Hi-Start Tubing and 250 feet of mono-filament. This rubber is intended for 2M-3M gliders.

Pilot/Reviewer
Skill: Novice-Intermediate. The weekend warrior who is slightly past beginner level, but not yet flying contests.
Although I've been flying RC Gliders since 1986, it was only on and off, and I just barely learned to thermal before putting it aside completely in 1998. I picked it up again in 2010, and have been hooked ever since. This year, I feel like I've finally graduated beyond the weekly cycle of fly - crash - fix - fly, and can usually find a thermal or two. And just so you know, I was not paid by Great Planes, and I bought this model and equipment with my own funds. The statements here are purely my opinion and done for the fun of it and in the hope that it helps anyone considering the purchase of this model.

Background
I wanted to have an open-class RE or RES sailplane for hi-start and winch launching. Even though I had an RES model on the building board, the build was taking me longer than expected because of my lack of available building time, and I didn't see my time freeing up for a while. I was also committed to keeping the budget low to save for some other higher priority toys. It looked like the BOT ARF fit the bill: open-class span and performance, with generous wing area and an airfoil that was designed to be more slippery with plenty of Phillips entry.

Flight Report
At the field around 8 AM the wind was dead calm, humidity around 90%, the temperature was at the dew point, and a thick fog was everywhere hovering around 20ft AGL. We decided to wait it out thinking that the rising sun would soon burn off the fog, so my buddy and I just shot the breeze while drinking coffee. By 9 AM the fog hadn't budged. I decided to assemble the Bird of Time ARF and throw some hand tosses to make sure it was okay for launch. After another half an hour, a slight breeze finally started to blow the fog away. After it cleared the area, which was the east end of a Navy OLF runway, you could see the back wall of the fog marching west down the blacktop.

Our winch was not available, so we had planned on flying electrics, and I also brought my NSP Pinnacle Standard hi-start for my pure gliders. I laid out the hi-start and hooked up the Bird while my buddy flew his Bixler. The first launch went well, just a nice easy glide back to landing to make sure all was well with the controls and balance. I was using a fair amount of hi-start tension, pulling back an additional 2x the length of rubber, about 200 feet of stretch. I could just barely hang on to the plane before release, and the BOT wings looked solid without any fluttering or flexing that was noticeable.

On the next flight, I got 3:04 minutes as I found some weak pockets of sustained altitude. Launch 3 was a good one, and I immediately steered downwind to where Don had specked out his Bixler. When I got there, I had only about 100 feet of altitude, the lower section of the thermal already gone, and I had to turn immediately around to get back to the LZ.

Then, after playing around for a bit with my ST Models ASW-28 electric, I launched the BOT a fourth time. It came off the tow as usual without much excitement, just a nice and easy fly-off at roughly 200 feet. I explored to the right without finding much. After turning 180 degrees to tack across the field, about midway across, the BOT just starts rising -- Eureka! I let it cruise a little more past the peak of lift, and start turning, just shallow easy turns because I didn't have much altitude. And every time I crossed that spot, I could see the BOT rise. At this point, I remembered to start my timer. After a few revolutions to center the thermal, I was up and away, and a vulture had joined me. The vultur e and i just kept climbing, very slowly. I took it up to almost speck, and the vulture bugged out. I kept going with it till I was fully specked out, and the stab disappeared. The thermal was very slow rising, not a hat sucker. Just a fat warm bubble is how it felt. It must have taken a full 3-4 minutes just to get up there. So I decided it's time to get out, and started cruising around. I must have caught another five thermals, the lowest one at around treetop height, and specked it out another couple of times. My neck started to hurt, and when Don asked me how long I'd been up, I looked down at my transmitter timer, which was at 24 minutes. The BOT caught another thermal while Don took a break and we chatted about books and movies. I think my thermal turns were smoother when I wasn't concentrating so hard. The BOT drifted down in sink, and half-heartedly trying, I couldn't care less and wasn't able to catch another riser, so I brought it around to final. When the BOT landed, the timer read 36:15 -- my longest flight ever.

Cons
  • Fuselage is not rigid in compression in the boom area. When you put your fist around it and squeeze, it easily gives. The gel coat may crack easily because of this. The tailboom is stiff in the vertical and horizontal directions however. So I don't believe that elevator response is hurt in any way by the "squeezable" fuselage boom. I did not mod it in any way to try and stiffen, and it seems fine in flight. It looks like some internal stiffeners have been installed along the lower centerline and maybe the top centerline at the factory. The wing saddle area and cockpit area are reinforced with plywood try and provide lots of rigidity there.
  • Weight is higher than it should be in my opinion. The nose is pre-ballasted, and I had to add another 1.5 oz lead in the nose, even while using a standard-size servo in the nose for the rudder.
  • Tail-mounted elevator servo -- adds tail weight and you are forced to use a micro servo for the elevator. The manual says that the counterbalanced elevator design eliminates the need for lots of servo torque, however.
  • It has a tendency to tip stall if you try to turn too tightly, even with lots of airspeed.

Pros
  • The BOT was ready to fly in about 5 hours of build and radio install time.
  • Very good L/D with flat, graceful, majestic gliding, both in straight flight and in shallow-banked turns. I was under pine tree top height around 2 football fields away and made it back to the LZ, taking a straight-at-me heading.
  • Signals lift very well, either with wingtip jostles or the rising of the entire airframe.
  • Seems able to climb in the lightest of lift.
  • Good penetration for an older design. At high altitude, to escape a thermal, I gave the plane a smidge of down elevator, and it moved out of the area very well and steadily.
  • Very responsive to rudder inputs. I'll probably program some dual rates on the rudder.
  • Great customer service. My fuselage had two 3/8-inch size chips missing on the gel coat where the fiberglass weave was exposed. I reported it to Great Planes, and they sent a new, perfect fuselage to me the same week.

Overall
The BOT ARF is a great value for someone wanting minimal building and open class L/D. You will have no problems launching from a 3M-rated hi-start, but I have yet to launch it on a winch and can't say how it will perform there. This glider is a model for an intermediate pilot, and possibly a beginner with expert supervision and/or buddy box: evident in its bolt-on wing design, lightweight wing construction, and precise control input requirements while flying. It's not a model you can get away with over-controlling, but it does provide a terrific glide and control responsiveness. A great performing sport glider, and with a few modifications, maybe an entry-level contest glider.
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Old Sep 03, 2012, 09:39 PM
Lapsus calami
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Joined Aug 2009
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What a good review; comprehensive, informative and very readable. I find a lot of reports needlessly filled with highfaluting terminology, proscriptive advice and patronising attitudes that say more about the writer than the aircraft. This article speaks to me directly without artifice or presumption. Thanks.
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Old Sep 04, 2012, 07:54 AM
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Don Bourdon's Avatar
United States, NC, Cajah's Mountain
Joined Oct 2006
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What mods would you suggest for an entry-level contest glider?

Thanks,
Don
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Old Sep 04, 2012, 10:54 AM
R2R
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St Johns, FL, USA
Joined Nov 2009
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Quote:
Originally Posted by Undercarter View Post
What a good review; comprehensive, informative and very readable. I find a lot of reports needlessly filled with highfaluting terminology, proscriptive advice and patronising attitudes that say more about the writer than the aircraft. This article speaks to me directly without artifice or presumption. Thanks.
Thanks for the kind words, Undercarter.
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Old Sep 04, 2012, 11:01 AM
R2R
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St Johns, FL, USA
Joined Nov 2009
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Quote:
Originally Posted by Don Bourdon View Post
What mods would you suggest for an entry-level contest glider?

Thanks,
Don
Adding spoilers would be good to make it easier to get the landing points. Others might have some additional suggestions, but spoilers would be the first and only thing I would do. If someone is just interested in learning the ropes of contest logistics, you could probably fly it as is and just focus on making your times. Coming from someone who has yet to fly in a contest, this is what I would do to get started.

Allan
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Last edited by R2R; Sep 04, 2012 at 11:09 AM. Reason: Added my disclaimer
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Old Sep 04, 2012, 01:24 PM
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United States, NC, Cajah's Mountain
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Thanks Allan.
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Old Sep 04, 2012, 07:26 PM
Mark LSF # 3792
United States, TX, Garland
Joined Nov 2008
700 Posts
Don't know if they have improved it, but the spar structure on the center section was suspect on the early versions. Would work OK on a moderate highstart, but "caveat emptor" on a winch or real unlimited class highstart! Also, seem to recall D.O. Darnell had a thread somewhere showing how to install spoilers after the fact.
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Old Sep 04, 2012, 09:43 PM
R2R
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St Johns, FL, USA
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Thanks for chiming in, Mark. I've heard that the first few runs of kits had the shear web grain in the wrong direction, but supposedly that has been fixed. If someone has opened up a wing and checked, hopefully they will let people know.
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Old Sep 21, 2012, 08:58 AM
Big Jim
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United States, ID, Mountain Home
Joined Jun 2011
2,958 Posts
R2R thanks for the review of the BOT. Will buy one next week. I am a true novice to silent flight and just maiden my Fling
Maiden Flight of my Fling Glider (4 min 11 sec)

I am curious to which high start I should buy or make. Can the Fling high start be used?
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Old Sep 21, 2012, 09:42 AM
Conroe,TX
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USA, TX, Conroe
Joined Aug 2004
53 Posts
Your hooked go ahead and open the wallet and as you well know there is NO cure. LOL
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Old Sep 21, 2012, 10:02 PM
Big Jim
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United States, ID, Mountain Home
Joined Jun 2011
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Quote:
Originally Posted by roboto65 View Post
Your hooked go ahead and open the wallet and as you well know there is NO cure. LOL
So True....and to think 14 months ago it started with a Champ and now with 18 planes 6 of them scratch build foamies I am now entering the amazing world of silent flight. I have done a lot with sport and 3d. My radian pro opened the door I used the motor for a launch device only but it was so easy to cheat as you would come in short or too fast and get a go around. IMHO silent flight captures the true essence of flight and takes all the skill I have to be accurate. After the Bird of time gets here I will try a DLG, but I heard the Fling DLG is a no go any ideas on which DLG a guy should start with?
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Old Sep 21, 2012, 11:55 PM
R2R
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St Johns, FL, USA
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RTF --
Nice video! And congrats on joining the world of pure sailplanes. Some nice flights you had for a maiden. The Fling hi-start won't launch your BOT ARF. The BOT ARF is about 8 times heavier than the Fling. I have a 2-3M rated hi-start and it just barely gets the BOT in the air at 2/3 max tension. You should go ahead and buy the Aerofoam Hosemonster for 3M. You can get the complete hi-start or the tubing and build one yourself. Lots of threads on hi-start comparisons on RCGroups. Hobby Lobby sells a decent 3-meter rubber as well, but most people regard Aerofoam Hosemonster as best. If you are short on field length, Aerofoam has a shorter zipstart also. Hosemonster Link

There is great discussion on technique and equipment in this thread. http://www.rcgroups.com/forums/showthread.php?t=155353

Good luck with the BOT, and let us know how it goes. I might be launching mine on a winch for the first time this weekend and will be sure to report back.

-Allan
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Old Sep 22, 2012, 12:11 AM
Big Jim
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United States, ID, Mountain Home
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Quote:
Originally Posted by R2R View Post
RTF --
Nice video! And congrats on joining the world of pure sailplanes. Some nice flights you had for a maiden. The Fling hi-start won't launch your BOT ARF. The BOT ARF is about 8 times heavier than the Fling. I have a 2-3M rated hi-start and it just barely gets the BOT in the air at 2/3 max tension. You should go ahead and buy the Aerofoam Hosemonster for 3M. You can get the complete hi-start or the tubing and build one yourself. Lots of threads on hi-start comparisons on RCGroups. Hobby Lobby sells a decent 3-meter rubber as well, but most people regard Aerofoam Hosemonster as best. If you are short on field length, Aerofoam has a shorter zipstart also. Hosemonster Link

There is great discussion on technique and equipment in this thread. http://www.rcgroups.com/forums/showthread.php?t=155353

Good luck with the BOT, and let us know how it goes. I might be launching mine on a winch for the first time this weekend and will be sure to report back.

-Allan
Sounds good and good luck,thanks for the link
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Old Sep 22, 2012, 12:27 AM
It's all fun till Crunch!
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InSane Diego
Joined Jan 2002
1,988 Posts
You look like you're having great fun, I wish I could find a lawn like tht to fly on!!

Envy, Envy!
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Old Nov 04, 2012, 07:59 PM
R2R
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St Johns, FL, USA
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I finally had the chance to launch the BOT ARF on a winch today. The winch line was almost straight into the wind most of the time, light, at maybe 2-4 mph. I launched it twice with no problems. I floored the pedal for the first 2 seconds or so, then did a moderately paced tap and even got a mild dip and 10-15 foot zoom at the top. I would say that the weak spars have been strengthened/remedied. But be carefull still, YMMV.
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Last edited by R2R; Nov 04, 2012 at 10:26 PM.
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