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Dynaflite Bird of Time ARF Sailplane

Reviewing the Dynaflite Bird of Time was a true time machine experience, taking me back to my childhood where I had a deep appreciation for the graceful bird-like wings adorning many of the Thermic kits that were available at the time. The Bird of time also took me back to my earliest days of R/C flying, when I first "earned my wings" flying pure sailplanes.

Splash

Specifications
Wingspan:118 in (2972 mm)
Wing Area:1050 sq. in. (67.73 dm 2)
Length:49 in. (1245 mm)
Flying Weight:60 oz (1700 g) listed; 58 oz as built
Wing Loading:8.2 oz/sq. ft (25.0 g/dm2) listed; 7.95 oz/sq. ft as built
Launch System:Dynaflite Standard Hi-Start
Radio:Hitec Focus 3 radio (Hobbico brand) / 1 Hitec HS-55 servo (elevator),
1 Hobbico CS-61 standard servo (rudder)
Price:$149.99
Available From:Tower Hobbies / Dynaflite

Introduction

Reviewing the Dynaflite Bird of Time was a true time machine experience, taking me back to my childhood where I had a deep appreciation for the graceful bird-like wings adorning many of the Thermic kits that were available at the time. The Bird of time also took me back to my earliest days of R/C flying, when I first "earned my wings" flying pure sailplanes. To this day I still love soaring, although I've done nearly all of my thermal chasing in recent years with electric-powered soaring machines. In a sense, reviewing a pure sailplane like the new Dynaflite Bird of Time ARF is a little strange to me, having devoted all my aviation energy to electric powered aircraft over the past number of years. On the other hand, it feels very natural, so it's kind of like coming back home. As a "homecoming plane", I don't think I could have asked for a better choice than the Dynaflite Bird of Time ARF. The Bird of Time undoubtedly ranks as one of the most beautiful planes of all time. There's something about the grace and elegance of this plane, with it's classic wing planform and flowing lines, that tugs at my heart like no other. I've wanted a Bird of Time almost since I began flying R/C, but a lack of building time kept one out of my hangar until now.

This new ARF does a magnificent job of removing the time dilemma with very fast, very easy assembly while offering even better appearance, now that the fuselage is molded in fiberglass. Rapid assembly and overflowing charm made the new Dynaflite Bird of Time ARF a "must have" on my list.

Kit Contents

Opening the Bird of Time box reveals some very pleasant surprises.

Dynaflite claims a 2-3 hour assembly time, and with the amount of prefabrication, they'reprobably not far off the mark. Most holes are pre-drilled, plywood structure isalready installed, and nearly everything is arranged to go together quickly andaccurately.

Assembly

Wing

Since this is a poly-hedral wing (no ailerons), assembly is fairly simple. Thefirst step is gluing the components of the wing joiners (dihedral braces) together (thereare two sets, since the B.O.T. uses a 3-piece wing). Each joiner is composed to twoaluminum plates and two plywood plates, with the aluminum plates on the outside. Ioriginally tried using CA to hold the components together, but the aluminum didn't bondwell so I used epoxy instead (as recommended). When the instructions tell you thatone end is narrower than the other, they're referring to the height dimension (top tobottom). I marked the ends of the pieces before I assembled them to prevent amix-up. After the joiners are completed, they're installed in the outer wing panels(narrower side). The fit is tight, and the instructions advise that you may need totrim the braces to fit. The plans call for gluing the joiners in the outer tippanel, but mine fit so tightly in the center section that I left the joiners as part ofthe center section.

After the joiners/dihedral braces are finished, an anti-rotation pin is epoxied intoeach wing. Make sure you don't push the pins in too far.

Adding the wing hold-down dowels and screw reinforcing plate finishedthe wing. The holes for the dowels are pre-drilled in the wing, requiring only anX-Acto knife to cut away the covering over the holes. The ends of the dowels goinginto the fuselage are rounded with a file before installation. I used Carpenter'sglue (Aliphatic Resin) instead of epoxy, with very good results (almost too good - itworked so fast I almost couldn't get the dowels back out when I pushed them in too far).

Installation of the wing bolt reinforcing plate requires cutting away the coveringunder the plate, and gluing the plate in place with the holes aligned. I usedaliphatic resin here also, holding the assembly together with clamps while it dried. Dynaflite gave a nice touch by having the hold-down plate pre-covered. I found theplate extended a little aft of the wing trailing edge when aligned with the bolt holes, soI trimmed the plate back once the assembly was dry.

Rudder

Both the rudder and the vertical fin closeout are pre-built and pre-slotted.

Dynaflite provides a sheet of hinge material from which 3 hinges are cut, and these areinstalled in the rudder with CA, then the rudder is joined to the fin and the hinges arelocked in with CA.

Rudder actuation comes from a long pushrod run through the pre-installedpushrod sheath. One end of the rod is threaded for the clevis. The other endis given a 90 degree bend for the servo arm (a nylon retainer holds the pushrod to theservo arm).

Pre-installed servo trays make servo installation for the rudder very easy. It's hard to get used to full-size servos after flying electrics for so long, but the extra weight is useful for this sailplane. Control horn and nut plate are trimmed to match the angle of the rudder before they're installed (otherwise the rudder travel would be hindered by the plates).

Stabilizer

The Bird of Time is equipped with a full-flying stabilizer, meaning the wholestabilizer moves for pitch control, as opposed to having a fixed stabilizer and moving therudder. This arrangement has certain aerodynamic advantages, but it can be tricky tobuild. Thankfully, Dynaflite made it very easy. A rod in the middle of thestabilizer serves as the rotation point. This rod, with flattened ends, slips intoholes in the stabilizers (going through the vertical fin) and is locked in place withsmall set screws. All the internal hardware is already in place. A rod on thefront of the stabilizer acts as the pitch control rod, sliding up and down in a groove inthe vertical fin. The front rod also fits in holes in the stabilizers, but it alsogoes through the clevis on the control horn in the middle of the fin. Dynaflite dida nice job in supplying the control horn pre-bent and pre-assembled with the customclevis.

Stabilizer servo installation is probably the most difficult part of thekit, and it's fairly simple. The trickiest part is making certain it's positionedproperly in relation to the stabilizer front bar. You'll need to use a micro servoin this installation; I opted for a Hitec HS-55. To set the servo up, I centered theservo arm and installed the push rod. Once I placed the servo and push rod in theirapproximate location, I pushed the front stabilizer rod through the clevis and centered itin the slot. With the clevis properly located, I could now position the servoproperly. Next, I removed the servo, attached the double-sticky tape to the backside, and reinstalled the servo and push rod (still keeping the pushrod clevis centeredwith the rod). Now that the servo was "stuck" in place, I epoxied the twoblocks on either side of the servo to the fin (before I installed the servo, I roughed upthe fiberglass with sandpaper and cleaned it with alcohol). After the epoxy dried, Idrilled and installed the plywood strap over the servo. As a side note, you'll needa 24 - 30 inch extension for the tail servo to reach the receiver.

Tow Hook

Tow hook installation is about the only step on the Bird of Time requiring measuringand drilling, but it's pretty easy. Mark a centerline along the bottom of thefuselage between 14 and 17 inches from the nose, make a mark along that line 15 inchesback from the nose, then using the pre-drilled tow hook block, mark the remaining holesand drill. The tow hook block needs to have the blind nuts inserted into the holesin the block, then it's epoxied into fuselage over the drilled holes. The tow hookcan now be threaded into one of 4 positions.

Radio Equipment

The servo installation has already been covered in the stabilizer and fin portions ofthis review, but here's how I installed the receiver and battery pack. There's notmuch unusual about my receiver installation - I simply used Velcro hook and loop materialto place it behind the rudder servo. My battery pack installation is a littledifferent, however. I started with a standard 600 mAh receiver pack in the nose, butI found the CG to be a little aft of the recommended spot (current notes on the Dynafliteweb site now give a CG range that would have been acceptable, but the instructions justsaid to place the CG 3 3/4 inches behind the leading edge), and I was uncertain about thequality of this pack anyway. So, borrowing from my electric power experience, Iplaced a 7-cell 1300 mAh NiMH flight pack in the nose and ran it through a CastleCreations Pixie 14 speed control, using the BEC capability to provide the correct voltageto the receiver. This pack fit the contours of the nose well (I used Velcro to holdit in place), and I can fast charge it before flying. Plus, the capacity is doublemy normal flight packs (just in case I catch a really great thermal!). This is asomewhat more expensive way to do things, but if you happen to have unused flight packsand speed controls laying around, it's not a bad way to make use of them.

As a side note, I made good use of left over equipment with thisproject. The transmitter, receiver, rudder servo, and battery pack all came from adefunct Hobbico Aero Cruiser!

Finished

Canopy, Decals, and Wing Bolts

Only minor items were left to complete the Bird of Time at this point. I foundthe gelcoat on the fiberglass partially covered the wing bolt holes, requiring a littlecleanup with a hobby knife before the wing could be bolted on. I cut the canopy alongthe molded lines and taped to the airframe with plastic packing tape. There's anoption to glue the canopy to a plywood frame and use a rubber band arrangement, but thetape method works well for me. Last but not least, I applied the decal to the rightwing panel.

All Done!

Here's what Dynaflite's Bird of Time ARF looks like when complete. Avery beautiful ship!

This is a big plane! My son, who's over 6 ft, 1 inch tall is holding the Bird of time in the above photo. That nearly 10 feet of wingspan stretches out a long way!

High Start

Launching the Bird of Time is accomplished with a Dynaflite standard Hi Start. 100 ft of surgical rubber tubing attached to 400 ft. of string serves to place the Bird ofTime approximately 500 ft into the air, placing it well into good thermal huntingterritory. Dynaflite recommends the standard Hi Start, even though it's usuallyrecommended for gliders in the 100 inch range, due to the light weight of the Bird ofTime.

Dynaflite's Hi Start launch system comes conveniently set up on a reel. The spike can be inserted in the center of the reel as an axle, allowing easy wind up of the tubing and string. Assembly requires tying the parachute to the end of the line (after untying the ring on the end), and tying the ring to the end of the parachute.

Flying

When the time came to flight test the Bird of Time, I decided to use a field next to a local school, since it met the criteria of having the space to set up the Hi Start and having an elevated area to conduct initial test glides. My test glides went well, giving me the feedback I needed to trim out the Bird of Time before attempting the Hi Start.

Launching with the Hi Start proved a little interesting. In my first attempt I didn't have it stretched far enough, leaving the Bird of Time in a stalled attitude without a lot of altitude when the Hi Start released. Thankfully, the Bird of Time has gentle flying characteristics and I pulled out without any problems, even gliding quite a distance in the process. After a few more experiments I found the way to achieve good launches was to pull it back until I almost couldn't hold it, then give it a good heave upward. It's still something of a leisurely launch, but it will get it up to altitude. I'm using the standard Hi Start, and it seemed at the edge of its capability (other, smaller gliders I've owned in the past rocketed up on the standard Hi Start). The heavy duty version would probably be a better choice for this plane.

The Bird of Time launches easily, although I felt the standard Hi Start was close to its limit. I think the heavy duty Hi Start may be a better choice.

Once airborne, the Bird of Time is absolutely delightful to fly and beautiful to watch. In a sense it reminds me of an ocean liner in the sky -slow and graceful, and requiring a bit of room to bring around. Thermal catching is easy with this ship (I caught a great thermal shortly after coming off the Hi Start on my first good launch), and the large wing span makes it easy to see. I found that the Bird of Time responds to the lightest of lift, giving good indication of thermal activity (just crossing roads on landing would cause it to bob up). Landing is easy - I never felt the need for spoilers. It just settles down gently. My only caveat is that as a large floater, it takes some room to turn and to recover if you get it into an unusual attitude. You just have to plan ahead a little more than you would with a smaller sailplane, but it's probably easier to fly otherwise. At the end of the day, I was all smiles. It's nice when a plane flies as well as it looks!

In the air the Bird of Time is every bit as graceful and elegant as its looks suggest. A sweet flyer, the Bird of Time seems to float forever, catching every little updraft along the way.

Conclusion

I have nothing but good things to say about Dynaflite's Bird of Time ARF. A great "kit", it goes together fast and easy, with many thoughtful steps built in.

As a flier, the Bird of Time is delightful, floating around in the lightest of lift with unparalleled grace and gentleness. Of course, the best aspect of the Bird of Time is probably its classic, beautiful appearance that stands out in any crowd. A definite winner!

Discussion

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Old Dec 12, 2003, 06:21 AM
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cold boy's Avatar
clandeboye, manitoba
Joined Nov 2000
152 Posts
Was the recommendation of the standard high start because of the light weight, or because of the wing construction problem? Better to address the issue and see if Dynaflight has made the changes. There is no doubt the Bird of Time is a beautiful classic design.
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Old Dec 12, 2003, 10:22 AM
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Punta Gorda, FL
Joined Apr 2002
4,952 Posts
Steven,

I'd sure like to know how much tension, in pounds, this model can take on the tow line without folding the wings. What size fusible link in the tow line would you recommend to avoid wing damage during launch? To me that is more important than all the other measurements in the specification.
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Old Dec 12, 2003, 02:12 PM
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nuevo's Avatar
United States, AL, Madison
Joined May 2002
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In the article, there is no mention of winch launch failers reported over and over in various mailing lists and this very site. We all know Dynaflite has made statements regarding this issue, and has made changes to the production of the kit.

This review continues makes me skeptical of published reviews.

In defense of reveiwers, I understand the delicate balance they have to perform. Bad reviews, and the editor won't publish it, because he'll run off the advertisers.

The intentional mention of the launching system (not a winch) makes me wonder. Hmmm.
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Old Dec 12, 2003, 02:52 PM
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ISoar's Avatar
Ottawa, Canada
Joined Feb 2003
163 Posts
Quote:
Originally posted by Ollie
Steven,

I'd sure like to know how much tension, in pounds, this model can take on the tow line without folding the wings. What size fusible link in the tow line would you recommend to avoid wing damage during launch? To me that is more important than all the other measurements in the specification.
Typically use 3 to 5 times the weight of the model in tension.

It is pretty hard to fold the wings using a histart in my experience. Generally speaking. I know Dynaflite explicitly specifies a hi-start for launching the BoT ARF.

I've never used a fusible link on a histart or winch. Not needed IMHO.
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Old Dec 12, 2003, 04:30 PM
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Steven Horney's Avatar
Joined Jan 1999
419 Posts
While I realize that quite a discussion has been going on regarding BOT wing failures under winch launches, the instructions specifically state that the BOT is to be launched by Hi Start only. Therefore I chose to review it that way. Besides, I don't have access to a winch. :-) My experience with the BOT is that it flies very well, and when launched as recommended there are no wing folding issues (as least as experienced by me). I don't know what the wings will handle - mine seemed reasonably strong (in my informal "bending" test), and I really didn't want to take them to destruction to find out.

To bring up winch launch failures in my review would have been slamming a product for use outside of its recommended envelope based on hearsay (since I haven't seen or experienced a wing failure), and that would be both unprofessional and unethical (in my opinion). Since the comments of others regarding the wings and winch launches are readily available on this web site, I felt that anyone interested wouldn't have to search far for the information. It seems to me that winching a plane designed only for Hi-Start launches is somewhat like powering an electric plane designed for Speed 400 motors with a brushless system - you're on your own at that point.

Steve
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Old Dec 12, 2003, 05:48 PM
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Punta Gorda, FL
Joined Apr 2002
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Steven,
Another point of view is that the market for the Bird of Time would be larger if winch launching were allowed using a fusible link. The question of the proper sizing of a fusible link doesn't slam the product. Why limit the use of this very attractive product to histart launches? I think that is an unnecessarily narrow approach taken by an unnecessarily defensive supplier.
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Old Dec 12, 2003, 11:35 PM
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Ray Lowinski's Avatar
Napoleon, Ohio
Joined Dec 1996
727 Posts
Steve,

Just to comment on your EP analogy.

I wrote to Dynaflite specifically to ask about the use of the BOT wing in an electric application. Their answer was just about as expected - It wasn't designed for that and so they won't comment on it either. I really like the idea of the 3 pc. wing but I guess I'll have to strip one and do mods if I want to go EP with it.

Keep 'em hummin'

Ray
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Old Dec 13, 2003, 10:47 AM
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Joined Sep 2002
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Quote:
Originally posted by Ray Lowinski
I wrote to Dynaflite specifically to ask about the use of the BOT wing in an electric application. Their answer was just about as expected - It wasn't designed for that and so they won't comment on it either. I really like the idea of the 3 pc. wing but I guess I'll have to strip one and do mods if I want to go EP with it.

Ray
Hi Ray,

I have just purchased a BOT from a reviewer from another model magazine. It hasn't arrived yet, but included a spare center section with spoilers installed and was offered at an attractive price.

I have plans to fly the BOT as a EP glider also. Two questions:

1. Have you decided on a motor system yet? If yes, what is it?

2. Have you actually researched whether the glass fuse has room to convert to EP?

I'm thinking I may buy a spare fuse(if there is room for EP gear) to convert to EP and save the original for pure glider. Or, if there isn't room, I'll build a wood fuse from the kit.

Sierra Gold
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Old Dec 13, 2003, 10:51 AM
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United States, AL, Madison
Joined May 2002
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Steven,

Thanks for the clarification. I disagree with the constraints by Dynaflite, as anyone who flies with a club most likely has no access to a hi-start.

That said, you tested it within the stated constraints. I understand your point of view as a reviewer.

I still believe you should have mentioned the failures, as responsible reporting to your readers. You know what the manufacturer said, but you also know that many many of the potential buyers of this kit are not likely to use it that way.

I have personally seen these failures, seen how the spars were built, and have heard from others that I trust. Since you don't know me, then I geuss you can call it heresay. What you call heresay, I call eye witness testimony.

Jon
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Old Dec 13, 2003, 10:59 AM
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Joined Sep 2002
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BOT EP conversion (or any other glider)

As stated in a message above, I intend to convert a BOT to EP.

I am operating on the theory that the stresses involved in "hard" high-start or winch launching are not present in an EP launch. This assumes EP launching is moderate and not "hot liner" style.

Is my operating theory correct?

My observations in converting a Hangar 9 Aspire glider to EP, is that the launch seems to be quite easy on that less than robust wing. (Hacker B20 L15, Maxon 4:1 GB, 11x6 prop, and 10 Kan 1050 pack. 39 oz. AUW and 60 degree climb out)

Sierra Gold
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Old Dec 13, 2003, 11:22 AM
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United States, AL, Madison
Joined May 2002
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Sierra Gold,

You are correct. The high stress part of flight is the launch.

The only other is if very high speed flight (i.e. dive) followed by a hard pull up on the elevator. That could happen on either type of plane.

As long as you don't fly like a hot-liner, or put the weight of 22 subC-cells in there, you should be fine.
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Old Dec 13, 2003, 11:41 AM
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Yep, I'm an OLD glider-guider and only want to watch the BOT float in search of the elusive thermal. No speed runs are planned.

Loved this plane since I first saw it in the 70s. Left RC for about 11 years and just returned this year. Really like the "freedom" of EP launches and the ability to operate from smaller fields.

Sierra Gold
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Old Dec 13, 2003, 11:48 AM
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United States, AL, Madison
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Welcome back to the hunt for thermals and relaxing afternoons circling in the sky. It is a pretty bird.
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Old Dec 13, 2003, 08:40 PM
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Miami Mike's Avatar
Miami Lakes, Florida, USA
Joined Mar 2003
8,484 Posts
Quote:
Originally posted by Steven Horney
While I realize that quite a discussion has been going on regarding BOT wing failures under winch launches, the instructions specifically state that the BOT is to be launched by Hi Start only.
They may have altered the manual after they discovered the defective wings, but my manual says no such thing. In the Takeoff section, on page 17 near the top of the left column, it says in part, "You must be very careful about how steeply you allow the model to climb. If the climb is too shallow, you will not get the full height from the winch or high start..."

My manual has the code "DYFZ5000 for DYFA0500 V1.0" in the bottom right corner of the front page.

Edit - Here's another thought:

Both my manual and the box my Dynaflite ARF Bird of Time came in say "Unlimited Class 3-Meter ARF Sailplane". Can you explain how one might compete in Unlimited Class Sailplane events with a sailplane that can't be winched?
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Last edited by Miami Mike; Dec 13, 2003 at 09:01 PM.
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