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Post by whatgoesup on Oct 28, 2010 11:33:44 GMT -5
Welcome to the discussion thread for the Bird Of Time - One Design Group Build and Contest. Please read the following announcement.     |
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Post by whatgoesup on Oct 28, 2010 11:54:58 GMT -5
Doing things together is part of the fun of this hobby/sport. So, let’s start a group build over the winter. LISF has done this before with great success. Let’s do it again. If you have not done much building, then building your model as part of a club group will be a great learning experience. There are experienced builders who will be available to help. This removes some of the uncertainties for those of us that are not great or experienced builders. Ask lots of questions, take your time building and you will have one beautiful bird. The BuildThe model proposed is the Bird Of Time. This is a classic design that is beautiful to see and has a great soaring reputation. You will fly this one with pride. The kit is well documented, has easy instructions and there are large build threads on the forums. Another attraction is that it can be built from plans, from a kit or as an ARF. This excerpt was taken from a review of what is now the nostalgia 108" version of the BOT, published in 1997. Note that the newer Dynaflite kit and ARF offered by Tower Hobbies are the 118" versions: The 108" wingspan of the Bird of Time Sailplane was designed by glider guru Dave Thornburg in the early 1970's for F3B competition, and the plane did quite well in overseas competition. In the original RCM construction article, Dave described the design evolution which led to the configuration first kitted by Mark's Models, which became Dynaflite several years ago. Dave designed the Bird of Time with a thin 9.5% airfoil for low drag in F3B speed and distance tasks, and paid particular attention to cleaning up the airframe to eliminate excess drag—still excellent design practice today, by the way! The distinctive pre-WWII "Wolf" German-style wing planform came about because Dave liked the looks, not for any theoretical reason. And the Bird of Time was designed with light extremities, light wing tip panels and tail surfaces to provide responsive handling at all speeds. The Contest There will be a One Design (OD) contest based on the Bird of Time. The fun of this type of contest is that everyone flies the same type of model. This is very popular in other clubs. You have heard people say that it is the pilot, not the plane that wins the contest. A one design contest proves it! Some people avoid competition because they feel their plane is not competitive. Well, in this contest you will be on equal footing with everyone else. All you need is a Bird Of Time (BOT) for the contest. Some of our club members already have a Bird Of Time. And those that would rather not build the BOT from a kit have the option of purchasing the ARF version. You can also purchase replacement BOT ARF assemblies and parts if something gets broken. You'll have plenty of time to build and practice as the OD contest won't be until the spring/summer. And if the contest is well attended and we like the format there is no reason that we can’t do it multiple times. Rules of the build if you want to fly it in the One Design contest:
* OK for plans, kit or ARF build
* OK for 108" nostalgia version or 118” version
* OK for carbon on the wood spar (remains woody legal)
* OK for larger wing rod
* OK to add spoilers, but they must be disabled for the OD contest
* OK to reshape and fiberglass the kit fuselage and finish it as you please
* OK for one, two, three or four piece wing
* OK to use either screws or rubber bands to hold down the wings
* OK to choose your own electronics and layout
* Decorate as you like
* No skegs will be allowed in the contest (you won’t need one)
* Other modifications: With the new launch approach, more leeway will be given to modifications as they will not make a major difference when launching. The basic guideline is to make internal improvements (lighter, stronger, easier to transport) and not external enhancements to the wing or tail group (bigger wing, different shape wing, different airfoil). The CD has the last word on whether a model modification may be entered in the one Design Contest. If your modification falls outside of these rules it would be a good idea to ask first.
There's a change. This change is to increase the fun factor by launching consistently high. Pilots will be allowed to choose between launching off the winch or a Hi-start. Previously everyone would have to fly off the Hi-start. Since all the planes that are currently known to be in the contest are capable of flying off the winch, and I'm pretty sure have flown off the winch, I expect all the pilots will pick the winch. The person operating the winch pedal will tap the planes lightly up the winch and try to make the launches equal, so that everyone is on equal footing with everyone else. Obviously the pilot can make the biggest difference in the launch. While we can discuss the rules of the OD contest, the plan is for this to be an open launch contest. Pilots will be able to fly off a hi-start or a winch. Flight tasks will be between 6 and 12 minutes. The landing task will be a runway landing so you can slide the plane in and still get a maximum point landing. No need for skegs or dork landings. Skegs will not be allowed. The OD contest date is July 24th. And When You are Done This plane should not become a hanger queen. It was chosen because people will want to fly it. Once you have finished the build you should have a beautiful 3M sailplane that can be flown for sport and which is very well suited for the monthly club RES contests or the monthly club unlimited contest. If you choose to carbon cap the spar and add spoilers you should even be able to compete in the ESL contests and place well. Many of our club members have won ESL contests with RES gliders. There is no reason this one would not place well in the hands of a practiced pilot in the ESL Sportsman class. A build thread will be established where we can ask questions and share our experiences. And there should be a LOT of show and tell at the club meetings as we progress with the build. This is going to be fun! Contact Trevor (powerbud@optonline.net) if you are interested. We will probably arrange a group buy of the kits so we can take advantage of discounts. If you are an experienced builder and would like to help others with a BOT build or modification, please say so in your response. Modified 07-15-2010Modified 11-03-2010 |
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Post by whatgoesup on Oct 28, 2010 11:57:45 GMT -5
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Post by whatgoesup on Oct 28, 2010 16:47:21 GMT -5
The 108" version of the BOT is the nostalgia version. The current BOT kit and ARF are 118". There could be some confusion because Tower Hobbies made the 108" nostalgia version of the manual available on the current kit's web page. Also the review that Tower Hobbies links to is originally from an article printed in 1997 for the 108" version. The Dynaflite manufacturers website and Tower Hobbies kit web page show the current kit version as 118".
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Post by whatgoesup on Oct 29, 2010 9:14:32 GMT -5
Carbon Spar by Pete Nicholson
Carbon laminates come in different lengths, widths and thicknesses. We would have to cut them to length for BOT spars: 0 .014 thickness for the top of the top spar and 0.007 for the bottom of the bottom spar. Note that the thicker piece of carbon goes on the top spar. This is because winch forces produce a compressive load on a wing spar, focused on the top spar. The bottom spar is under tension and carbon is very strong in tension. The carbon comes in 0.375 width, the same width as the 3/8" spruce main wing spar of the BOT. Carbon is epoxied to the wing spars before assembly with laminating epoxy.
This space is reserved for future notes.
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Post by whatgoesup on Oct 29, 2010 17:48:01 GMT -5
A compilation of lessons learned during the group build and contest.
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Post by whatgoesup on Oct 31, 2010 9:49:50 GMT -5
Reserved
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petefly58
LISF board Member 
LISF Secretary
Posts: 33
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Post by petefly58 on Oct 31, 2010 9:56:47 GMT -5
As luck would have it, I have a set of BOT plans which I bought from RCM Plans Service which I've had since the 90s. It has all the rib profiles. Right now I'm using trace paper to copy all the ribs and other parts to use as patterns to make the wood parts. I have a lot of accumulated scrapwood from other builds, gonna use as much of this as possible. My goal is to scratch build an extra BOT wing which will be stronger than the stock wing but not in the class of a Bubble Dancer. As of now, I plan to use .014 carbon on the top spar cap and .007 on the lower spar cap. If I decide to wrap this with kevlar thread or tow, it will require wrapping the fishbone assembly before gluing on the upper and lower sheet, leading edge, trailing edge, etc, as in the Bubble Dancer or Allegro Lite. Some builds on the internet show the spar being wrapped, some builds omit this step. Well, back to tracing parts for now.  Pete |
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Post by whatgoesup on Nov 3, 2010 7:54:21 GMT -5
Everyone, please note that a change has been made to the One Design build and contest rules. (See the first post of this thread.) This is to satisfy recent requests for many types of modifications to the builds. Most center around strengthening the spars, but there are and will be many others if a change isn't made. So ...
To allow as much flexibility in each individual's build, but still keep a level playing field for the contest, only hi-starts will be used in the One Design contest.
If you want, enjoy building a Bird Of Time for the winch. Make other improvements, too. You'll have a plane that will be competitive for more than just the One Design contest and you can do it as part of a group of builders.
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Ed Anderson
Junior Member
LISF President
AMA Leader Member
Posts: 71
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Post by Ed Anderson on Nov 3, 2010 12:24:30 GMT -5
Trevor, You and Peter are doing a fantastic job getting everything ready to support the club on this build. As you know, I am not much of a builder, but I am getting charged up over this group build. I am going to be actively clearing stuff off the workbench to get ready for this. I hope to start over the Christmas holidays when I have two weeks vacation planned. Peter, I would like your opinon of making this a solid center section with removealbe tips for a 3 piece wing. Would this be very difficult? It would travel and store much more easily that way. Ed Edit - Found someone who did a 3 piece wing. Much reading to do. www.rcgroups.com/forums/showthread.php?t=518499&highlight=bird+time+buildAnd www.rcgroups.com/forums/showthread.php?t=269207 |
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Post by whatgoesup on Nov 3, 2010 15:24:03 GMT -5
Thanks Ed.
Pete and Ed,
I'm also interested in a three piece wing and would add that I want my center section to be bolted on and I'd like spoilers, too.
My BOT kit was shipped 11/1 and is on the truck to be delivered today, 11/3. Wow! That was speedy-quick considering it was sent UPS Ground; 7.8 pounds of joy.
Note: I'm updating this post 11/4.
When I opened the box all the wood was bowed in the same direction. Maybe it something to do with lying flat in the cold and then coming into a warm house. One day later, after laying flat with the box open and the wood laid on edge, the wood has almost completely straightened out.
So now I have this kit and I still haven't figured out all the modifications I want or how to do them.
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Post by whatgoesup on Nov 3, 2010 18:52:17 GMT -5
I received the 118" BOT kit tonight. The box says it's a 118" and the instructions inside the box are for the 108" nostalgic version. I pulled the plans out, of course they don't say which version they're for, and measured one half of the wing, which came to 59". So the box and plans agree that this is a 118 " kit. We can also see how Tower Hobbies makes the 108" manual available for the 118" kit: it's in the kit's box.
Hopefully this will help anyone ordering the kit feel a little more comfortable about what they'll receive.
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Ed Anderson
Junior Member
LISF President
AMA Leader Member
Posts: 71
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Post by Ed Anderson on Nov 4, 2010 14:10:12 GMT -5
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Post by whatgoesup on Nov 4, 2010 15:22:41 GMT -5
Builders in the One Design Group Build And Contest: ----------------------------------------------------------------  Build Questions: --------------------- Frank Strommer, go-to-guy for build questions, joined, 20101101, LISF |
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Post by whatgoesup on Nov 4, 2010 19:42:15 GMT -5
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