New scratch-built Bird of Time

[schrederman]

I didn't like the kit I got from Dyna-Flite, so I cut one out and and added a few mods. With spoilers and a considerably beefed spar she weighs 44 oz. and flys very well.....:D

Jack Womack

[sierra-gold]

A true work of art on one of my all time favorite gliders... so beautiful in the air.

Oh that we all couldn't be born with the skills you obviously have and probably refined in building 100s of planes.

As I read on another list... if 44 oz. proves to be too much to take, you can always send it my way. :D :D

Thanks for sharing. Now, where is the construction video of your BOT? :)

Bob Goldsmith

AMA 12351

[schrederman]

I could show the video, but then I'd have to travel the country and kill you all!!! Not a good way to win friends and influence people... Did I mention that she'll take a full pedal winch launch?

Jack

[targetdrone]

Originally posted by schrederman
Did I mention that she'll take a full pedal winch launch?

Jack

Obviously, you haven't launched it on my winch. At our last contest, I reminded people at the pilots meeting that our winches had heavy braided line with very little stretch and were quite strong. We had only one failure on launch - I managed to blow off my own stab.:eek: How ironic.

David Judson

[Ollie]

Beautiful work, Jack!

The moral of the story is that developing craftsmanship is an investment that continues to pay off for a life time.

[Rob Nelson]

Hi Jack,
A true inspiration!
I should have the Dynaflight kit landing on my doorstep in the next few days...How bad was your kit??
Would you care to share what mods you incorperated, with a few details? Don't need the video (I value my health), but a few questions come to mind...
Q1 Just how did you make that spar?
Q2 What method did you use to activate the spoilers?
Q3 Your fusalage looks amazing, along with the rest of the model. How did you finish it?
Q4 Is that a bolt on wing?
Sorry for all the questions Jack...I guess it's the price you pay when you post a picture of such a beautiful sailplane!
Cheers,
Rob

[schrederman]

The spar is oddly made. The carbon is unbroken through the main panel. I used .007 uni carbon and the laminations from the bottom of the wing are as follows: The sheeting is laid out only as a spacer. Use thin mylar or equivalent to keep epoxy off the sheeting. .007 X 3/8 carbon with epoxy - 1/8 X 3/8 spruce - 3/8 vertical grain balsa and ribs all glued with aliphatic resin - 1/8 X 3/8 spruce - .007 X 3/8 carbon with epoxy but only to 2/3 span of inboard panel - 1/8 X 3/8 spruce - .007 X 3/8 carbon with epoxy to ends of main panel. The center section of the spar is shear webbed all the way in to the center rib / bolt beam. The center joint is capped on both sides by a 3/32 ply dihedral brace. The bolt beam is built of .060 X 1/2 carbon pre-preg with hard balsa shear webs. It's 2 1/2 inches long and 5/16 thick. It is fit through a slot in the dead center of the wing center section after both panels are built and joined. The left panel must be built with the carbon unbroken and hanging in place to build the right panel. The right panel is then built with the dihedral set in the left panel and it all has to be kept straight. The sheeting is omitted so the joiner boxes may be wrapped with carbon or Kevlar tow.

The spoilers are string activated with 1 85 servo in the nose. There's a 1500 mil pack in there, too. The fuselage is made of 1/8 airply sides and 3/8 balsa, and it's just Monokote all over.

The wing bolts go through the bolt beam into strategically located bulkheads. with the aft bolt to keep things aligned. The tip panels are plugged on using 3/8 aluminum tubing joiners with .060 wall thickness. The tip panel spars are spruce on top and hard balsa on the bottom.

It flys better than I expected. The kit that I bought looked like die cut oak. I have never seen balsa that hard or that heavy. It was amazing. I made plywood templates and copied the plans, and built over the copy using wood I selected. Someone else decided to do the same thing and bought the kit...

There is really nothing magic there. Anyone can build one of these bullit-proof Birds. It is only fair to share your ideas and experiences. I hope to see some of yours, soon.

Jack

[John Gallagher]

>The kit that I bought looked like die cut oak. I have never seen balsa that hard or that heavy. It was amazing. I made plywood templates and copied the plans, and built over the copy using wood I selected. Someone else decided to do the same thing and bought the kit...

I had to do the same thing with the Skeeter kit. Dynaflite must have a farm where it grows the petrified balsa.

John

[Rob Nelson]

Thanks for all the details Jack. Just may put them to good use.
Well, my BOT arrived on my doorstep today. With all the comments on wood quaulity, I just had to take a look and pass it on. You're right...The wood is heavy. Even looks like oak. I will be substituting some of the wood for lighter stuff for sure. I won't even have to make ply templates...Just use the supplied parts!The die cutting seems to be acceptable though.
My bigest disapointment (I guess I was expecting the wood) was the supplied wing joiner and the arrow tubes. On the Dynaflight website it states that the kit comes with a "large 5/16th wing joiner", but a 1/4 joiner is supplied. The 1/4" joiner is shown on the plan and is listed on the parts sheet. I realize that BOT has been flying for years with the 1/4" joiner...Just thought they may have updated the kit as so many of the re-kitted sailplanes have gone. Skybench comes to mind.
Is the 1/4" joiner bar ok with a beefed-up spar, or should I replace it with a 5/16" rod. As a matter of fact, a 5/16" rod may even fit the supplied "arrow tubes" better than the supplied rod.
And what about the arrow tubes..What have folks being doing with them.
After all that... I think it's a beautiful sailplane, and am looking forward to building it.
Cheers
Rob

[schrederman]

Hi Rob,

Maybe you have the Bird of Time and Skybench's Bird series mixed up, or maybe the newer kits haven't made it into circulation yet. I didn't use the center joiner at all because of my 3-piece wing. I joined the wing at the poly breaks. That way the strength of the center doesn't rely on a heavy joiner. The 1/4 joiner isn't adequate for a strengthened wing. My wing would bend it with no problem. If you build it stock, it should be fine. If you beef the wing, you will need to add some joiner strength to go with that. I didn't see 1/16" of slop in the arrow shaft tubes. I would recommend some thin wall aluminum tubes or brass tubes for your joiner system. I used some heavy wall aluminum tubing for my poly-break joiners but some short pieces of the supplied joiner system would be OK, too. While the Bird of Time has been around for a long time, it was designed before the strong winches of today were in use, and lots of contests were run with Hi-Starts. It was more important then to build light and keep the sink rate as low as possible...or so we thought. A good launch in those days was obtained by kiteing up as vertically as possible. If you want, I'll take a close-up of my center and poly breaks and post them here.

Best of luck, whatever you do...

Jack Womack
real men scratch ..... build!

[Rob Nelson]

I tried my 5/16" Oly 2 rod on the arrow shafts..didn't fit. I suppose there is not 1/16" slop after all.
Maybe Dynaflight is going to update it..or was it a mistake in the add. I emailed Dynaflight to let them know. In any case I'll plan on a 5/16" rod with brass tubes with a stronger spar.
Cheers,
Rob

[omega blood]

That looks great, I'm green like the plane with envy.

[Ric Duley]

Originally posted by schrederman
If you want, I'll take a close-up of my center and poly breaks and post them here.Hi Jack,
Let me also compliment you on an absolutely gorgeous plane. :cool: I'm even more green with envy than omega blood. ;)

I plan to start building one soon. I recently picked up an old Mark's Models version of the kit. I haven't yet looked closely at the wood to see if it's worth using. If not I'll scratch build it also.

I'd love to see any additional pictures you'd like to post. I especially like your 3 piece wing idea - sounds like the way to go.
Please tell & show us more.

[Rob Nelson]

Just thiught I'd pass on a quick note on my earlier post regarding the wing joiner rod supplied with the Dynaflight kit. The advertized "large 5/16" wing joiner rod" was indeed a misprint. The Dynaflight site has been corrected to 1/4" rod...No update for the kit.
I to would be interested on the three piece wing details.
Cheers
Rob

[BMatthews]

Gorgeous..... absolutely gorgeous. The skies are a more picturesque place since that Bird was launched.

And KUDOS on learning the TRUTH about scratch building. It's really the ONLY way to fly... :D

I've met VERY few kits in my time that I consider worth the money.

[schrederman]

Ric, Rob, and others that are interested......Here are some of the details of the 3 piece wing. I'll post these pics 1 at a time so not to clog things up too much. Sorry for not getting these in sooner, I had a woody event to run...only to have the second day rained out.

Enjoy.

Jack Womack

PS. This one is of the bolt bulkheads.

[schrederman]

The bolts are recessed except for the rear alignment bolt. They are down on the bolt beam that's part of the center section rib.

[schrederman]

This is pretty straight forward...

[schrederman]

3/8 Aluminum tube joiner with .060 wall thickness, with angle set in root of spar, joiner is straight. BTW, carbon rod was heavier, and I haven't noticed needing it.

[schrederman]

Final fit.

[Ric Duley]

:cool:

Jack,
Thanks for taking the time to post the pic's & descriptions.

[Rob Nelson]

Thanks Jack. Certainly appreciate all the info and photos.
Cheers,
Rob

[Wildbill10269]

Originally posted by schrederman
I didn't like the kit I got from Dyna-Flite, so I cut one out and and added a few mods. With spoilers and a considerably beefed spar she weighs 44 oz. and flys very well.....:D

Jack Womack

Beautiful BoT! What is the weight of the wing alone?

[schrederman]

WildBill

The wing weighs 23.1 oz. That's 14.4 for the center section, and 4.4 and 4.3 for the tips.

Jack

[Svengali]

Here's another BoT, just finished... pretty much stock except for the spoilers and flaps.

[Svengali]

One more...

[schrederman]

Nice Bird...spoilers and flaps, makes it eligible for the 15 meter class......

Jack