Great Planes Bird of Time EP Sailplane ARF - Model Aviation magazine

[@kenwebster5053]

10 feet is, or at least was the normal wingspan for contest RC sailplanes back in the 70s. For a while, there was a push for 100-inch 2ch standard class, about 8 feet. I think the UK was a driver for that class, but the US flooded the hobby with a 6-foot 2ch standard class, that seems to have become the standard in the 80s. Personally, I think the flight performance in the 100 inch class far exceeded most if not all 6 foot designed at the time & I was very disappointed that the LSF did not continue with the 100 inch class. My memory is that the bird of time plans were published came to market about 1978 or 79. The wing plan is actually a mistake. In the 1930s or so, several gliders were found to have poor aileron response. Rather than go through the expense of a redesign, the developers simple replaced the ailerons wing broader ones. That is the real reason for this wing plan, it was a cheap way to resolve poor control issues. It is a small performance detriment because of the way it alters the spanwise AAOA. That is, it adversely rotates the L/D vectors along the span. The 2 most efficient planform solutions based on different design constraints are attributed to Ludwig Prandle based on his lifting line theory. If the design constraint is wingspan, then the most efficient plan form is an elliptical wing. If, however the constraint is the wing rood bending moment, then a longer span can be carried by tapering and twisting the wing to produce what became known as a bell shaped spanwise lift distribution. This takes the tips out to the zero-lift point & is commonly referred to as the Prandtl wing, also used by the Horton brothers in their flying wing designs. Prandtl's 1930s single sheet double sided paper on this pretty much went under everybody’s radar, possibly until well after WW2. I read an article on it in 1981 & it seemed an aerodynamic revelation then. You can find KZbin videos of students designing, building & flying Prandtl wings as NASSA course projects. It also solves the adverse yaw control issue & gives rather significant performance efficiency improvements. To the best of my knowledge, all of the information I have provided here is correct for a flight mechanics & historical perspective. The bird of time design gains its performance from it’s wing section. It is a thin section with a symmetrical nose section (Philips entry). This effective gives the section a small camber, which means its optimum L/D performances is high & occurs at low angle of attack & high air speeds. This gives the model a flat and fast glid which is very advantageous to having the range to search & find lift while lightly loaded, especially in windy conditions. However, on a still & inactive day, a high lift floater will outperform the Bird of Time’s duration simply because it has a slower rate of sink. To be competitive, the Bird is time was a model that had to be flown tactically, exploiting its speed and flat glide slope to find lift. A skilled pilot could usually do very well with it.

[@ramimehyar481]

Best model review i have ever watched in my life, you have a talent.

[@jamesfalardeau3886]

That wing shape goes back to 30's or 40's hence the name. I built some really old Jasco/Jetco kits in the early 70's like the Thermic 50X free flight tow lines. Built a BOT in the early 80's from scratch from plans and it was my all time favorite. Everyone else was into Sagitta's and Paragons.

[@petercyr3508]

Saw the wing on one of these explode. Grain on the shear webs was running horizontal instead of vertical. Buy the way, the original kit by Dave Thornberg in 1981 came out at 40 oz.

[@paulbroyles1996]

Extraordinary commentary.. thanks

[@oneskyrc9182]

Excellent review. I love mine. Timeless classic ! Beautiful on the ground and in the sky.

[@allenmoore9848]

BOT is very hard to beat. I have made my wing joiners permanent in the outer panels. In that way the main section is able to fit back into the box it came in, along with the panels for transport protection. I now have just acquired a second one and will customise it with spoilers and transparent film to show off those wings and assist with landings.

[@garryperrin2408]

How did the spoilers go? On the ARF, correct?

[@awuma]

0:38 Late 1970's :-) Wuz there... Absolutely classic shape. Incidentally, a three metre is easier to fly than a two metre, so after you've mastered the basics and worn out a cheap two metre or less, a three metre is perfect for getting to learn soaring. I see the wing joiners on this plane follow the same idea as the jointer on the Spirit ARF. CF rods may be more convenient if one is building such a model.

[@paulschwartz7902]

Thanks TERRY. Great review

[@michaelkrailo5725]

I built one of these in 1987 and had a .15 glow motor on the front for power. I flew it many times but got bored and started doing some crazy dive loops and eventually folded the wings. So the advice to not stress this bird out is well taken. I would be interested in a mini foamy version of this now. Just miniaturize everything and I would have a lot of fun with that.

[@michaelkrailo5725]

@@StrangerInAStrange That's pretty cool John. I would like to build one of these too.

[@valerysh3153]

Very good, received great pleasure from your flight and the story of the glider. Thank. / Russian/ Очень хорошо, получил огромное удовольствие от вашего полёта и рассказа о планере. Спасибо.

[@richardbertacchi5016]

Always wanted to build one......If Sky Bench ever gets a kit available I'm in.

[@tonyaccurso1090]

Great video! Thanks Terry.

[@Follkuhley]

Great presentation, clear and understandable comments for my german ears. All essential informations about this model and amazing flight pictures. Thank you!

[@Paul1PA]

Superb BoT review Terry!

[@Twobarpsi]

I've been waiting for an electric version of this since the 80's!!

[@mentuemhet]

it's discontinued

[@Twobarpsi]

@@mentuemhet I'll build one from plans then. The airfoils will be hard. Perhaps there is a person selling a foam wing?

[@mentuemhet]

@@Twobarpsi you might as well get a glider that has flaps and ailerons for this size of a plane as the bird of time. may i suggest you perhaps buy a glider like this type from esprit tech. you should take a look at their planes.

[@22alexii]

being a new modeler we find means and methods hard to find, so we just stumble upon them, like this.. AND you can use minwax wipe on poly and rust-oleum oil base enamel directly on FOAM, we discovered this while painting an Arrow foam Corsair. I happened to get some oil base paints on the foam packing and realized that not only does it not dissolve the foam, it bonds very well to the foam. We even poured some paint thinner on the foam and it pooled on the foam but Did Not Dissolve the foam. The cheap paint that came on the plane peeled off with some Blue tape after I had painted over it with some latex water base paints; So now I am using poly (not water based) or oil base enamel to prime and harden foam Yes, you can coat your Foam plane with oil base poly, paint etc, resulting in a Hard structural skin.

[@usafr1pilot]

Thanks for the video. love the explanation and editing is great.

[@WowRodg]

Good review, nice pictures, thanks

[@scottheffernan5286]

Where can I purchase one today?

[@WHURobKip]

Great video! I'm yet to maiden mine.. are the wing tips just a push fit or do you tape the seams?

[@rodneysmart9774]

Very well done video. Thanks

[@vonSchwartzwolfe]

very well done video.

[@thebagnanofthebrothel]

Can you tell me where I can buy the bird of time

[@johndunstan3875]

Brrrr winter in America is cold. I'll stay in Western Australia. Winter here 27c 😍

[@THEFALCON58]

shame we can't get these no more in western Australia

[@Johnny-tt8zc]

I still want one of these.

[@alpeshchaudharyfilms7294]

so beautiful

[@ToddBreda]

I finally was able to snag one of these (now discontinued) BoT EPs, completely NIB. I am stoked! Great review very helpful!

[@bodieismael9244]

Sorry to be so offtopic but does anyone know of a trick to get back into an Instagram account..? I was dumb lost the account password. I love any help you can offer me

[@otiskareem6043]

@Bodie Ismael instablaster :)

[@bodieismael9244]

@Otis Kareem I really appreciate your reply. I got to the site through google and Im waiting for the hacking stuff now. I see it takes quite some time so I will reply here later when my account password hopefully is recovered.

[@kevinburns8343]

Great review / how long are your flights for the batteries with no thermal s in the cold weather ? Thanks for any information Kevin

[@Weirdflight]

It's hard to say. I was never going for duration. I'd fly for a few minutes, then land and warm my hands in the clubhouse for a bit.

[@iotaprime2892]

Nice camera setups

[@garryperrin2408]

Really great video! Would you be at all concerned if in a turn it was steeped at high angle? What tape did you use for wing panels?

[@Twobarpsi]

I wish it had spoilers. Do you feel the plane is manageable without them? Any creative ways to add them??? Thanks 👍

[@skilletthandle]

Great job Sir. Thanks for your time. I will look at Bird of Time before I buy again. Again, Thanks.

[@AlexDiesTrying]

Hm, and it really doesn't need ailerons or flaps? It is one beautiful plane for sure.

[@THEFALCON58]

these gliders are hard to find in Perth Western Australia

[@THEFALCON58]

Hi you may need more down thrust to make it fly straight 2or3 deg / down and right 2or 3 deg glider flyer and Builder for 30 years

[@Weirdflight]

You're probably right. But it would be tough to adjust the thrustline without surgery since the firewall is molded into the fuselage.

[@THEFALCON58]

@@Weirdflight pack the inside with 1/8 washers and thread lock from the inside keep the washers inplace dont want it stalling on take off or the wind pushing the glider over your head behind you .?

[@THEFALCON58]

@@Weirdflight washers and longer bolts

[@THEFALCON58]

Hi got mine now, lots of mods, smaller servos,in ways to make this glider lighter.? the tail crack is rubbish, circuit board material is good.

[@markryan3018]

LOL! The nose is icing up at 7:25

[@alansolko7696]

Nice video

[@1bizjets]

Looking at buying this glider. Great video presentation.

[@thomasjones3384]

Where did you set your balance point. The model calls for 3-3/4 "?

[@oneskyrc9182]

Nice job on the video. A bit more detail about how you installed your stabilator would have been great. I bought this ep version of the B.O.T. & it is a fantastic flying classic ! Really love it and get a lit of compliments on its size and shape of wing.

[@Weirdflight]

I installed the stab per the instructions. Is there anything specific you'd like to know?

[@petehibbard2189]

Where can I buy the bird of time ep arf in the USA

[@harrybrinck5305]

How do I sell a EP/BOT?

[@ricardoponcini6914]

Qual helice vcvesta usando.

[@craigschray4486]

I have been searching for this model. Are they still available?

[@garryperrin2408]

What is EP? I thought that was styrofoam. Hoping someone answers. Thanks for excellent video!

[@modelaircraft]

Hello Garry! Styrofoam™ is a registered trademark of DOW Chemical Company and EP or EPS is the generic term for all Expanded Polystyrene. Kind of like saying Kleenex™ instead of tissue.

[@antok.juni.beonehousehotel5249]

Good

[@shckltnebay]

It better weigh less than 5 lbs lol, my ARF with added motor is 4lbs and its a tank, Mine is nicknamed the Bird of Destruction

[@Weirdflight]

Ha! I like that name.

[@123cp8]

Sigh... does anyone build anymore?

[@220volt-u7]

albatros