Sub 250g RC planes

[Quorneng]

I build planes from thin sheet foam, see "Lightweight EDFs"
Although I started doing this well before the 250g category was established I discovered several planes I had built were at or near this limit.
The obvious first candidate was the 40 mm EDF DH Venom built in 2mm Depron.

True scale, although not a scale colour scheme, it weighs 202g with a 1400mAh 2s LiPo. A slow and detailed build with the ducting executed with great care to ensure the best possible EDF efficiency.
This video is of a typical flight that reached 8 min 45 seconds.

Unusual for an EDF particularly for a scale type let alone for one below 250g.
The efficiency of the ducting shows particularly when flying at reduced throttle setting. A specific "endurance" flight at just a minimum throttle reached a rather boring 12 minutes!

This set me thinking what might be done with a conventional tractor layout plane but one specifically designed to be below 250g.
I followed my usual "pod and boom" layout but coupled with a fairly high aspect ratio 40" (1020mm) span wing built in 2mm Depron with a balsa spar.

The boom is from a cheap glass fibre fishing rod. The "pod" is built from 6mm Depron and holds the Rx, 850mAh 3s LiPo and a 20A ESC. The motor is a Blue Wonder 1300kV out runner turning a 7x6 prop. Note the motor is carefully faired in but still exposed enough for adequate cooling. Ready to go the "Light Tractor" weighs 219g.
With a full power thrust to weight exceeding 1:1 it has a vertical capability and easy aerobatics.

But it is at reduced throttle that shows what it is all about with a continuous cruise endurance of just over 1 hour.
So far so good but how about a sub 250g 40" span Scale Super Cub?

 

[CertifiedMike]

The video of the glider flying against the sky reminded me very much of Pink Floyd Goodbye Blue Sky vid.
These vids make me want to go out and buy a sim so I can learn to fly like you do!

 

[Quorneng]

The Super cub was the first plane intended to be sub 250g.
The object was to be as large as possible and with an "Alaska" size wheels so it would stand a chance of taking off from my rough(ish) grass field.
This is how it ended up.

As you can see it weighs 242g!
The wings and fuselage are built from 2mm Depron. The fin and tail plane are 3mm Depron.
The motor is a 24g 2805 1500kV driving a 7x6 prop from a 1000mAh 2s.
The front of the canopy is the battery hatch and also gives access to the Rx and the 20A ESC.

To ensure it can out below 250g the wings are just Depron skins over a Depron spar. Each wing is just glued to the fuselage and relies entirely of the 1/16 balsa struts for bending strength. The bottom of the struts connect to the rear undercarriage wire just as it does on the full size.

The Super Cub uses 4x3.7g servos.
It has plenty of power. Just look at the length of the grass compared to the size of the wheels

It is also fully aerobatic. A 10 turn "Falling Leaf"

 

[Tunedfrog]

Pretty awesome, I tried building foam planes but failed miserably.
Thanks for sharing.

 

[CertifiedMike]

I've read other builds where the scale model is true to its 1:1.
When I build my 1/10 scale buggies, there isn't much that relates to my 1:1 cars or trucks.
How important is it to be familiar with 1:1 planes when building a kit? (Wondering as a noob in awe of these builds!)
I would imagine that when custom building a plane, that knowledge would be much more important.

This plane looks slow and easy to fly. The take off looked almost vertical! I guess you got your wish with the giant wings and short runway!
I must ask tho, please refrain from posting any more of those trick flight vids until I am a master pilot!
That falling leaf trick was really cool!!! I am impressed!!!

 

[tudordewolf]

Those are some awesome builds that really show how much potential there is in an optimized design.

What's the wingspan on the cub?

 

[Quorneng]

Those are some awesome builds that really show how much potential there is in an optimized design.

What's the wingspan on the cub?

It is quite large for its wight (242g) at 1020mm (40" ) span. As a result it is a true slow flier.