Yet another Bird of Time (BoT) build thread.

[sneasle]

Hey guys. I just finished my new Workbench (http://smg.photobucket.com/albums/v280/sgcool195/Workbench/) specifically for this plane (24x80" surface) so it is getting to that time for me to start my BoT build. If anyone is interested in the bench let me know as I have my planes scanned already with cut lists and have a 3D model made

This may turn into a dual build thread if I can get my buddy who will build one along with me to make an account.


Anyways, I won't start this for a week or two, but I want to get some feedback on some ideas of possible modifications. So far these are what I have in mind:


Bolt on wing (maybe).
Top and bottom spoilers (with the ability to disable the bottoms if needed).
Ballast tube (any suggestions on how to do this/what to use?).
FG the nose back to the tow hook.
CF pushrods or Goldenrods, depends on how the ballast tube works out.
Spoiler servo's in the wings (2 HS-81MG's probably).
Possible joiner upgrade.
D-tube sheet the wings out to at least the end of the middle panel, maybe farther. - - - - it looks like the D-tube already continues out to the wingtips.
Upgrade the shear webs (Not sure yet, I need to look at Dr. D's mini paper on sheer webs in balsa again).

I think that about covers the mods I have in mind. If anyone knows of anything else that would be a good idea to change, let me know. This build will take me a while as I like to build slow and check and double check everything.

Also, does anyone know if there is a 3-view for this plane somewhere? I want to throw it into photoshop and start working on the covering scheme. If you've seen any really cool covering jobs, feel free to post them.

[Hossfly72]

It makes me happy that I'm not the only one who writes out a list of mods, upgrades, changes and experiments before I even start the kit! I'll be following your build since the BoT's my favorite plane and I'm working on a 40 inch version myself and need some inspiration to finish. Then I build the 60 inch version. I miss my 2 meter version. Used to slope combat it against foamies (and win!).
I saw a joiner upgrade somewhere on these forums I believe that you might be interested in. Take lots of carbon tow. More than you think you'll need. wet it out with resin and pull it through a bent aluminum tube that matches the dihedral angle you need. Make sure it's stuffed tight when you pull it through and good and wetted out. Let it dry and then dissolve the aluminum in a hydrochloric solution. The guy that did this suggested using swimming pool chlorine tablets dissolved in a bowl of water to get a good, rich solution. When the aluminum is gone, you have a preformed carbon fiber joiner rod that matches your dihedral perfectly. It's beyond me though. For my little hand launchers, it'd just be overkill! LOL

Hoss


PS-- Sneasle? Cool monicker there. Sounds a bit like a hobbit or something

[sneasle]

Thanks! I like to think it will help me keep on track once i start the build.

I've done quick a bit of searching the forums on the BoT in its various forms since I joined the forum and I have never heard of the joiner mod you mention. You are correct, it does sound a bit excessive. I was thinking of sanding the stock one down a bit and wrapping it in CF cloth or tow.

Thanks. The nick was given to me by a couple of my female friends in high school. Bit of a weird story behind it, but that isn't really appropriate for the forums ;) .

[sneasle]

NOT GOOD:

I just opened the box to pull out the directions to flip through it while I was laying in bed so I could mull over the build in my sleep.. well, the instructions weren't in the box. I guess that when I took them out 6 months ago I never put them back... Not a good way to start the build...

[jcpatrick]

Warren Man-Son-Hing built a beautiful BoT (http://www.badger.rchomepage.com/bot.html), fixing one of the plane's only faults, the over-raked rudder. Both he and Tony Estep use a Drela-style composite spar to beef the wings up, but Estep (Bird of Future) modified the airfoil too. I've never heard if that was worthwhile.

Does anyone know where to get a "bubble dancer pod from Bud Elder"? There's a dozen recommendations to use this, and nowhere to get them.

[StevenatorLTFO]

Sneazle, you can get the instructions online, at the dynaflite website.

Steve

[StevenatorLTFO]

http://manuals.hobbico.com/dyf/dyfa0500-manual.pdf

[sneasle]

Thanks guys. I will make use of that if I can't find the original manual.

JC, your saying they removed some of the rudders angle? What does that serve to accomplish? I guess it would make the rudder easier to hinge (and possibly give it more symmetrical movement?).

Drela -type spar? I am not familiar with that.

Edit: Your link was for the ARF, this is the kit. I did find the kit manual on the site after a bit of looking.

[Wazmo]

JC, your saying they removed some of the rudders angle? What does that serve to accomplish?
From the beautiful BoT (http://www.badger.rchomepage.com/bot.html) link above:
The original version has an angled rudder hinge line, I hated the turn response on old planes with this setup. You get a bunch of pitch response whenever rudder control inputs are given.

[StevenatorLTFO]

Whoops, my bad, here is the right link if anybody else is looking

http://manuals.hobbico.com/dyf/dyfa4502-manual.pdf

I flew the BoTARF all last year, didn't really notice any pitch up with rudder application, but others have mentioned it in the past, so maybe its more noticible with an aft CG (mine was pretty set fairly conservatively. I sold it at the end of the flying season, but in the meantime picked up a set of plans, I'd like to scratch build one, so I'll be watching this thread with interest!

Steve

[jcpatrick]

There's a ton of elevator pitch response from the rudder. When I earlier complained on this thread (http://www.rcgroups.com/forums/showthread.php?t=840278) I got ignored. Glad I later found my observation was right. [The pitch response will vary depending on CG, OA weight and ballasting, and speed.]

Man-Son-Hing's tail keeps the look while greatly improving the function. His elevator —an adaptation from the BubbleDancer— is a lot better. Dynaflite wants you to put the servo in the tail (!) and the alternative is to put a bell-crank instead with the servo up front. Neither is as good as the V-mounted elevator.

[WimH]

Warren Man-Son-Hing built a beautiful BoT (http://www.badger.rchomepage.com/bot.html), beautiful? :eek: I'd call it ugly....Don't like pod and boom fuses

[sneasle]

There's a ton of pitch response from the elevator. When I earlier complained on this thread (http://www.rcgroups.com/forums/showthread.php?t=840278) I got ignored. Glad I later found my observation was right. [The pitch response will vary depending on CG, OA weight and ballasting, and speed.]

Man-Son-Hing's tail keeps the look while greatly improving the function. His elevator —an adaptation from the BubbleDancer— is a lot better. Dynaflite wants you to put the servo in the tail (!) and the alternative is to put a bell-crank instead with the servo up front. Neither is as good as the V-mounted elevator.


I would hope the ELEVATOR had lots of pitch response...

My plans show the bell crank, which is probably what I will use to keep my weight as far forward as possible.

I've also changed my mind on control rods, I think I will use goldenrods or something similar so I can run them down the side of the fuse so make room for the ballast tube.

[jcpatrick]

OK, ya' got me! I changed 'elevator' to 'rudder'. Dunno what I was looking at.

[sneasle]

beautiful? :eek: I'd call it ugly....Don't like pod and boom fuses


Well, it wasn't really a BoT anymore.. more like a BD with a BoTish wing.

[sneasle]

Its ok :).

So there might be an issue with the rudder inducting to much pitch in a hard turn. Can't this be solved by keeping your finger active on the elevator or by mixing in some elevator if you move the rudder close to its end points.

[bobby legue]

With the rake left in the rudder I can hook some air and put in some turn trim then set the radio on the ground and eat my sandwhich. It seems just fine to me.
Bobby

[sneasle]

OK. I guess I will build the rudder stock (I may take out 5 degrees or so) and just trim in elevator as needed. I've got a 9303 now so I shouldn't have any problems working it out :) .

[bobby legue]

Its gonna be an easy job, I assure you!
Bobby

[sneasle]

I hope so. :)


edit:

I just got back from campus. There is a copy place nearby that I was told could make large copies for a good price so I took the BoT planes with me. $10 for two copies, not that bad of a price. This should let me cut the plans up as I need to so I can build the wings on the new big bench and build the fuse and tail on the old bench.

[Hossfly72]

You need to meet your FedEx guy and convince him to fly. I started copying plans left & right when I realized we get a discount at Kinko's!! 5 copies for $9. And in 3 different sizes! I figure 20 years with the company and it finally paid off! LOL

It's funny that you're thinking about taking the slant out of the rudder. I've been thinking about rebuilding the rudder on my Skeeter with a little extra slant just so it will pull up by itself in that thermal turn. And I'll look for that custom carbon wingrod thread. It may be too much messy work, but it was pretty interesting.

[sneasle]

Hehe. Naa, I don't mind paying $5 per copy. That is very reasonable compared to some of the other places around here want to charge. Its a college town, so they think they can get away with charging an arm and a leg for large scale copies for Engineering and Design students.

Idk.. If I take any of the rake out it won't be a lot of it.

Ya, the carbon looks pretty cool. Kinda of excessive though. I'd have to find a piece of aluminum with an ID very very close to the ID of whatever tube goes in the wing. It may just be better to use a CF arrow shaft or something similar.

edit:

I will update and edit the original post with page numbers and details as the build progresses. That should make it easier for anyone else who comes behind me to get a quick overview of what is going on.

[BenH]

I really don't think that the Bird of Time or Dave Thornberg would have such high reputations if there were a problem with the sweep in the rudder axis! In fact, the BoT - built to the original plans - is known as one of the best handling RE sailplanes. Just my humble opinion . . . .

-Ben

[Hossfly72]

I miss my 2m BoT. I GAVE it away to a friend. I sure hope Karma exists, cause if it does, I've got loads of it to spare!

Hoss

[sneasle]

Fair enough Ben!

[sneasle]

Random quick question. Is the elevator on the BoT removable? The way it is drawn on the planes makes it appear as if it could be. If so, then that would be great for me because I could then store it in a gun case under the bed :).

[StevenatorLTFO]

Yes, it slides off the two pins. The way the fin, and the actuating rod are designed, you won't loose the rod inside of the fin.

Steve

[sneasle]

Nice, That should make me love this plane all the more.

another wonderful random question, Does anyone know if anyone has build a BoT with the two tip panels removable? If I can find a way to make them removable I think it would be very easy to store this plane in a gun case as I would not need to deal with the dihedral of those outboard tips when trying to store the wing..

edit:

Does anyone have a link for the sheer web papers written by Dr. D? I think there were two different ones, one for composites and one for balsa.

[arukum17]

That workbench is beautiful. Makes you feel like building

[sneasle]

Yup, It sure does.

The only problem I have to work around now is how to keep the cat off the plane while I am working on it.

[solo6796]

Nice, That should make me love this plane all the more.

another wonderful random question, Does anyone know if anyone has build a BoT with the two tip panels removable? If I can find a way to make them removable I think it would be very easy to store this plane in a gun case as I would not need to deal with the dihedral of those outboard tips when trying to store the wing..

edit:

Does anyone have a link for the sheer web papers written by Dr. D? I think there were two different ones, one for composites and one for balsa.


Here is my thread on a BoT with 3 piece wing....

http://www.rcgroups.com/forums/showthread.php?t=269207


AJ

[FrogChief]

PICTURES!!! This thread is useless without pictures!!! :D :D :D :p

[sneasle]

Frog:

Once I start building I will have pictures. Right now I am gathering ideas for changes and putting together a list of what I will need to make those changes. I like to build efficiently and that requires me to have everything ready at the beginning. If not, it just causes problems and delays later on.

AJ:

thanks for the link. I will read through your thread in detail before I start cutting, but this is a busy week as it is the last week of classes for me.

[ejett]

I built one with three piece, bolt on wings as well, about the same time as Solo. I did a build log on here as well. It isn't difficult to do the modification and I would definitely do it three piece again. My build thread is on RC Groups as well.

http://www.rcgroups.com/forums/showthread.php?t=242106

EJ

[sneasle]

Thanks EJ. I'll add it to the list of reading materials for the weekend.

Care to summarize how you did the 3 piece bolt on wing?

[ejett]

It is much better explained by going through the build thread, but in essence, I added bulkheads in the fuse to take wingbolts, built the center section by combining the two inner wing sections into one with a wide center rib with hard point (1/4 ply) inside for the wing bolts.

The joiners were initially plywood the width of the spars, glued into the outer wing panels and fit into joiner boxes built into the ends of the new center section. I later changed that arrangement because I broke the ply joiners twice on one wing and once on the other. I used a steel joiner inside brass sleeves as the replacement. I wanted to use CF rod, but didn't have any. I had no more problem after that.

The all wood spar I had was plenty strong for sport flying, but I broke it because I pulled up too quick on a zoom while the winch was still pulling. It folded outside of the ply doublers. The center joint did not fail.

In any case, the 3 piece is a very worthwhile project and I believe it to be stronger than the stock two piece wing. Solo used CF on his spars and is stronger still. His build has good pictures and write up too. He had some coaching and mentoring from the famous Jack Womack of Houston Hawk fame.

I really liked my BoTs. (I have had two including the ARF which is fairly heavy but flies great anyway. Its problem is the wing is not strong enough for winching IMO.

EJ

[sneasle]

Just went through my box.. looks like one of my sheets lost a piece when it came from the factory. What to do.. make my own replacement, or hit up dynaflight?

edit:

I've pulled all of the die cut pieces out of the sheets. I'll post weights for the wing ribs, the fuse sections, and the 'R' pieces tmrw.

[ejett]

If it is just one part missing out of a sheet, I'd just make it from the outline in the sheet from the appropriate stock, if I had it. If not and I had the patience and time to wait for the mailman, I'd call Dynaflite Customer Service. I'm sure they will send you a new sheet right out at no charge. I probably wouldn't be able to wait for them and just go ahead and make up the part from all the several hundred pounds of assorted scrap pieces I have laying around. Of course, you might not have the same amount of "stuff" I've got.

More than once, I've thought about scratch building a plane out of all the scrap pieces I have laying about in old kit boxes. I think it would be a fun project to do and I could name the result "The Scrap Pile". But I digress.

EJ

[sneasle]

Ya, I considered that. I bought this kit a while ago.. over a year ago from tower. It has sat sealed in the closet until I opened it up. If they think it's been too long I'll just cut my own.

Any particular weights of any particular woods ya'll want me to post?

[ejett]

It might be interesting to see what kind of wood weights are in your kit. My kit had very hard balsa that looked like oak. Not all of it, but some of the rib sheets and the wing tips, tail die cut parts and bulkheads. I recut some of the wing tip and tail parts because the kit pieces were so hard. I didn't have a scale at that point so did not get any weights.

I used most of the wood that came with the kit. I believe my all up was 54 oz. Jack Womack's BoT built about the same time came in in the low 40s. I would guess his would climb in sink at that weight. I really, really liked the way my BoTs flew.

EJ

[sneasle]

Jack is a master. I only hope this BoT comes out half as good as his.

[sneasle]

OK! Update with some weights.

Wing ribs, including the ply ribs and 2 rubber bands: 4oz

Fuse Formers: 1oz

stab parts: 1oz

wing tip parts: 1.5oz

rudder parts: 1.5oz

Fuse parts: 6oz

fin skins: 1oz

Anyone see anything there that looks wrong or too heavy? Any other weights that may be worth posting at this point?

[bobby legue]

Fin skins seems a tad heavy. Thats just me though. Anyone else?

[sneasle]

Skins are made from 1/16th and probably have 20 square inches each. My scale isn't the most accurate as I used the heavier scale (tops at 7lbs) since I couldn't find my smaller 8oz scale.

Also, the replacement sheets from dynaflight/greatplanes game in from the parts that had gone awol from that one sheet. They sent two sheets which was rather nice so I will nitpick those parts for weight and quality.

[sneasle]

Wow, this thread got old and died.

The BoT is in line for the board this winter. I'm gonna go ahead and buy servo's for it, Any recommendations?

I was thinking HS-82MG for rudder, HS-81 for elevator, and either HS-81's or HS-65's for the spoilers. Sound ok? Too much, too litte?

[solo6796]

I used 85MG for rudder and elevator. 55's for spoilers. No problems...

AJ

[ejett]

I also used HS-85MG for rudder and elevator and HS-55's on the spoilers. The HS-82MG might be fine, but wasn't available when I built mine.

EJ

[TheNightowl]

Can I stick a couple of dumb questions in here? I've been studying my plans for the Bot. I understand how the elevator works. But what isn't clear to me is what keeps the two elevator halves ON the pins that go through the tail. It's not like there is a centerline you can tape.
Thanks.
Nightowl

[sneasle]

It's a good question. I think some have used pins in the past, but I think the design calls for a friction connection of some sort.

[williamson]

Can I stick a couple of dumb questions in here? I've been studying my plans for the Bot. I understand how the elevator works. But what isn't clear to me is what keeps the two elevator halves ON the pins that go through the tail. It's not like there is a centerline you can tape.
Thanks.
Nightowl


The elevator halves are held on by friction. A neat trick that I have learned is to use Post-It glue. This is the non-drying glue used on Post-It notes. This glue can be bought in the form of a glue stick. I rub some of this glue on the two piano wires for the elevator. The elevator halves are gently forced onto the wires. The halves stay there and come off with a gentle consistent pull.

[kzimmerm]

The elevator halves are held on by friction. A neat trick that I have learned is to use Post-It glue. This is the non-drying glue used on Post-It notes. This glue can be bought in the form of a glue stick. I rub some of this glue on the two piano wires for the elevator. The elevator halves are gently forced onto the wires. The halves stay there and come off with a gentle consistent pull.


This works great however I have found that the glue stick adhesive is somewhat corrosive and will actually rust the pins. You can simply clean them off with sandpaper.

Kurt

[BatteryJockey]

If you go to the sewing section of most stores you will find Bee's Wax. It is used to stiffen thread to help thread needles. I rub it on the pins of the rudder before putting the 2 halves together. If you are still worried about the grip you can also put a piece of thread in the tube before putting the 2 halves together. Some people also put a small bend in the wire so it will not move easily when in the tube. Good luck with your build, I have just started on my 3rd BOT build. I will be streching the wings to 148" And the fuse to 60". I already have the 2 outside panels built, each one streched by 2". I will be adding 12" to each of the inside panels and then picking up 2 more inches by makine the wings plug into the fuse.


Gilbert

[TheNightowl]

I'm planning on a few mods myself. I want to make it a three-piece bolt-on wing, with a carbon-capped, kevlar wrapped center spar and detachable tips. I'm looking at maybe thinning out the fuse some and glassing it, as opposed to using lumber for the the dugout canoe used on the original. And building up the fin to try to save some tail weight. Actually, my plan doesn't call out the thickness of the balsa used on the fueslage sides, but I'm guessing it's 3/16ths. I don't have any 1/64th ply large enough for the front doublers, so I was considering going with 1/8th balsa on the fuse, using 1/32nd ply for the doublers, and just filling between the doublers with 1/32nd cross-grained to the main side, rounding it quite a bit and glassing it. Planning on a 6V 5-cell AA 2000 mAH battery with an Electron 6 receiver. I haven't decided on servos yet.
Nightowl

[sneasle]

sound like some nice mods guys


I don't plan on stretching it in any way, but I am planning on building the wing as a bolt on and building the wing in a way that it can be broken down into at least 3 peices that will lie flat in the back seat of my car...

I'll use HS-82MG's on rud/ele and something hs-65 ish on the spoilers i think.

I do plan on changing out some of the kit wood as it looks like some choices weren't the best, and I may glass it in some areas... I'd like it to be able to pull out of a very very hard dive without breaking in half..

[marc 540]

My kit came with 1/8'' balsa for the fuse and 1/16'' balsa for the doubler's. The 1/8'' balsa was very heavy and replaced with much lighter balsa. The balsa doublers stiffen it up quite a bit.

Marc 540

[sneasle]

I posted weights for most of my parts one page back, take a look.

[TheNightowl]

Been looking over and comparing some things. I think I'll go with HS-225MG's for R&E, and probably HS-55s on the spoilers. The 225s may be a little overkill, but then again, they may still be in there working in 15 years.
Nightowl

[sneasle]

225 should be fine. Price is good, they are worth considering against the HS-82MG's. I would say it depends on location, if you put them in the tail, go with HS-82's, if you put them closer tot he CG, the 225's should be fine.

I would go with 65's on the spoilers, or at least a knockoff bran with a bit more umph. I would hate for my spoilers to fail if I were in a bad spot and needed to get down fast. If you design a very good linkage, you might be able to get away with a 55s, but I was planing on doing top and bottom spoilers so I'll need the extra boost.

[sneasle]

Question:

Any of you guys that have built BoT's already, how much nose weight did you have to add? I'm considering building a second fuse and throwing a BL motor in it for the days I don't want to take the hi-start tot he field..

[RX7MARK]

I'm planning on a few mods myself. I want to make it a three-piece bolt-on wing, with a carbon-capped, kevlar wrapped center spar and detachable tips. I'm looking at maybe thinning out the fuse some and glassing it, as opposed to using lumber for the the dugout canoe used on the original. And building up the fin to try to save some tail weight. Actually, my plan doesn't call out the thickness of the balsa used on the fueslage sides, but I'm guessing it's 3/16ths. I don't have any 1/64th ply large enough for the front doublers, so I was considering going with 1/8th balsa on the fuse, using 1/32nd ply for the doublers, and just filling between the doublers with 1/32nd cross-grained to the main side, rounding it quite a bit and glassing it. Planning on a 6V 5-cell AA 2000 mAH battery with an Electron 6 receiver. I haven't decided on servos yet.
Nightowl

Nightowl,
You should check out the Balsa Sailplanes Yahoo group. A few years ago Tony Estep designed, with help from the group, a new 3 peice wing with a kevlar wrapped carbon spar and AG series airfoils for the BOT and called it the BOF (Bird of Future). Laser Arts still sells a lazer cut partial kit of all the ribs and shear webs and the wing plan is on the Yahoo group data section.

I have all the parts and I am about to start my BOF build. I am also planning to do a glassed, thinned, and lengthened fuselage and some of the lightning tricks you mentioned for the fin and rudder.

Should be a great sleeper, the looks and grace of the BOT with the strength and airfoils of a modern RES.

Mark

[sneasle]

Sleepers are nice.

Have a link for that group by chance?

[TheNightowl]

Nightowl,
You should check out the Balsa Sailplanes Yahoo group. A few years ago Tony Estep designed, with help from the group, a new 3 peice wing with a kevlar wrapped carbon spar and AG series airfoils for the BOT and called it the BOF (Bird of Future). Laser Arts still sells a lazer cut partial kit of all the ribs and shear webs and the wing plan is on the Yahoo group data section.

Mark
Hi, Mark. Yeah, I belong to the Sailplanes group on Yahoo. I've got the downloads of Mr. Estep's BoF wing plan, etc. (I always wonder if he is related to the surgeon who cracked my chest! His name was Estep.) Can't afford the short kit right now; wish I could. There is some thread here on RCG (need to go through my looong list of subscribed threads) where someone built up a carbon/kevlar reinforced center spar on a 3-piece wing BoT. I just need to look it up again when I get to that point.

For any interested in checking it out, the group is here: http://groups.yahoo.com/group/balsasailplanes/
Nightowl

[RX7MARK]

Hi, Mark. Yeah, I belong to the Sailplanes group on Yahoo. I've got the downloads of Mr. Estep's BoF wing plan, etc. (I always wonder if he is related to the surgeon who cracked my chest! His name was Estep.) Can't afford the short kit right now; wish I could. There is some thread here on RCG (need to go through my looong list of subscribed threads) where someone built up a carbon/kevlar reinforced center spar on a 3-piece wing BoT. I just need to look it up again when I get to that point.

For any interested in checking it out, the group is here: http://groups.yahoo.com/group/balsasailplanes/
Nightowl

I have a link to a 2-piece wing BOF build that I think is similar to the one you are thinking about. I plan on using the bolt beam idea that is presented here: http://www.badger.rchomepage.com/bot.html

Very nice build, but I am going with a more traditional fuse and Mr Estep's 3 piece AG foiled wing. I have everything to do the build just have to get started.

The laser cut BOF short kit is very well done and worth every cent!

Mark