My BOT, 43oz superb!

[Cebola]

My BOT, 43oz superb!

Today I make some test flying whit my new BOT, which I decide built light, and strong.

The wing spar is using 1/2X1/8 spruce, whit a cap of carbon fiber, on both spars.
Webbing in ½ vertical grain soft balsa, and fiber glass cloth around.

All balsa sheet type competition and super monokote for covering.

The result 655 grams for the fuse ready whit batteries, 570 grams for the wings, and 45 grams for the tabulator, plus 35 grams for the wing joiner.
Final weight -1305 grams or 43oz.

Some changes I made, increase the rudder course for 2”, made very light wing tips, also stabilator.

The wing center panel is tremendously strong, and this reflects on a superb glide ratio, and a dramatic climb on full pedal winch.

Hope you like it.

Cebola
Brazil

[scaflock]

Looks Great Cebola! At 43 oz weight it should fly as good as it looks. For some reason you look a LOT younger than I thought you would be. ;)

Jeff

[schrederman]

Beautiful...:D

Jack

[tonyestep]

Ceb, your planes are always gorgeous and this one is right up there with the best of them.

[atmosteve]

I would just love to see her rise quickly at the pedal, it looks a suberb sailplane! Happy flying Cebola.

[AndyTheLegend]

Sheesh! My big E-BoT comes in at 68oz.! Still thermals in light air and sure is a beauty... Congrats, and lets us know how the maiden goes.

Andy

EDIT: You already did it maiden it...

[PizzaHunter]

Colours like on Ukrainian national flag)

[Cebola]

In fact the colors of my BOT are a little controversial.
The idea was make a scheme whit transparent blue on upper surface, and transparent yellow, on under surface. And invert on the opposite wing.
In flight this means green, and works properly, except for my wife that get disappointed whit BOT in overall appearance.

Well, I like it despite all my friends and family consider strain a architect model, whit so exotic color layout.

The point is BOT still a fantastic model, and on this one I use the original Dave Thorberg design and plans, also the airfoil.

This is the same concept that I use in 1979, to participate of South American Championship on F3B , and achieve first place.

Regards


Cebola
Brazil

[rabidrue1]

Cebola she is a beauty.Can we get come close up photos of the new girl?By the way I thought that you were staying away from c/f after the kidney thing.

[Cebola]

Cebola she is a beauty.Can we get come close up photos of the new girl?By the way I thought that you were staying away from c/f after the kidney thing.


Hi Rabi

Some details of my BOT.

The joiner I made using one torsion bar of an old Volkswagen, cost a big work to fit :o

Fuse on balsa, and a glass cloth of 3/4 oz in two layers, and pacer finishing resin.

For coverage I use a horrible to apply Supermonokote, in a new version (worst than the old one).

The wing and tail group I use spruce spars reinforced whit a layer of carbon fiber.
About the tow hook, this is a remain, of my antique BOT, very interesting and strong, also commendable.
Has you can see, no spoilers (they never close properly), and for strong thermals I use my pilot skill, and a very strong wings (and also avoid to get extremely altitude).

The joiner is very thin, but was designed for cars, I think strong enough for a BOT joiner, until this moment, very resistant.
Inside the wing a box made in spruce, reinforced whit Kevlar, and glued whit epoxy between the spars, two sheets of 1;16 plywood vertical grain goes from the root rib, at the dihedral joiner.

Hope you like it.

Cebola
Brazil

[Hossfly72]

Your craftsmanship is incredible! Beautiful job Cebola!!!

[Cebola]

Your craftsmanship is incredible! Beautiful job Cebola!!!

Hi Hossfly


Thank's for the nice words


and.....Sorry for.....my English :(

Just terrible! :D

Cebola
Brazil

[rabidrue1]

Nice,I had not thought of making a wing joiner from a V/W torsion bar but they are made from better steel than most of the joiners I've seen.Don't worry about the english as most of my customers don't do near as well.

[marc 540]

Cebola,
Now that's what I call a ''real" woody!!! Nice...

Marc 540

[Cebola]

Cebola,
Now that's what I call a ''real" woody!!! Nice...

Marc 540

Hi Marc

Considering Dave Thornburg advices, BOT must do not exceed 41oz, mine is a little bit heavy (43oz), and I am considering change the rudder, for a build one in balsa stripes.

This makes possible to remove 1,5 oz from the nose (has ballast).
At this moment my BOT uses 3 oz of nose ballast.

My old BOT weights only 40oz RTF, and many advices of Dave Thornburg was considered at that time, like rounded leading edges, and a very light tail group.

In conclusion, this BOT was made using balsa scrap and Dave original plans, I think whit better result compared whit a BOT kit available on the market.

Stronger, faster, and very nice on thermals.

Regards

Cebola
Brazil

[marc 540]

Cebola,
My BOT ARF weighs 61 oz. and fly's good. My BOT kit weigh's 45 oz. but have not flown it yet. Some people say anything less than 50 oz. is too lite but I don't Know. I think at 43 oz. it should fly awsome!!! 41 oz is probably the very minimum. I would not worry about 2 oz.

Marc 540

[Cebola]

Hi Marc

The big problem is not overall weight, but tail heavy.
For any extra gram on tail, you can reduce 3 times the nose ballast.
And in fact rudder has to be light and straight, also maintain the airfoil shape.
My BOT rudder blade weights 1 oz, and this can be reduced for ½ oz or les, this could means 1,5oz on nose ballast, or no ballast on the nose.

I took very seriously Dave Thornburg advices about BOT, and this is an old article from 1979 published on a magazine about BOT construction.

Bellow Thornburg article


Cebola
Brazil