Community Spotlight: Behemoth Hughes H-4 Hercules

If you know Flite Test, you'll know we love big builds. Here's a community member's project which ticks all the right boxes.

The H-4 Hercules was an absolutly enourmous machine with an almost equally enourmous legacy. You'd have to be crazy to attempt to build a giant, 12ft wingspan scale model of this thing, but - oh wait - one of our awesome communty members has! This is Horseman3381's H-4 Spruce Goose.

"the flying boat [...] conforms to my moto of “More motors, more better”.

Eight motors mean eight times the fun, right? Actually, that is surprisingly accurate. You can read all about the history of huge seaborne monsters in this recent article all about the Flying Boats of the Golden Age.

A Story of Ambition

If there were seven wonders of the aviation world, the H-4 'Spruce Goose' would be one of them. This ambitious project was headed by Howard Hughes, the man behind the XF-17 Flying Crane (the largest helicopter in the world).

The H-4 remains the largest wooden aircraft ever to have flown with a wingspan longer than a Boeing 747. In fact, it has the largest wingspan of any plane - period.

The aircraft is nicknamed the 'Spruce Goose' for one very good reason: it was made almost entirely out of wood. Due to wartime restrictions on materials when the project started, the entire airframe was put together using traditional wooden construction techniques. If you've read the recent article on the de Haviland Hornet, another aircraft built using this method, this should be quite familiar to you.

On November 2nd 1947, the Goose took flight for the first and only time from Los Angeles harbor. I, for one, wish I'd been there to see! Here's the video of that historic moment.

Building the Model Behemoth

Like the real thing, in model terms, Horseman's H-4 Hercules is also huge. Its wingspan is a whopping 12ft (or thereabouts). So he could transport the aircraft, Horseman scaled the model around a few practical factors.

"To determine the size of the plane I decided the wings would be removable but the fuselage needed to fit in my car, in one piece, without leaving the back open. This limited the fuselage to 8’-6” long which put the wingspan at 11’-10” and maximum prop size of 8”.

When embarking on a giant build of any type, you should know that the numbers often get a little crazy. If you want to know some more about the specific specifications of this monstrous foam board plane, helpfully Horseman has included a detailed description of what went into this plane and how large it really is.

Spec

Wingspan – 11’-10”
Fuselage Length – 8’-6”
Motor – (8) Turnigy D3548/4 1100KV
ESC – 70A
Prop – 7.5x4 4-blade
Batteries:
- (8) 4s, 4000mah Lipo for motors
- (1) 2s 1900 mah LiFe for receiver and controls
Servos:
- Aileron – Hitec HS-5495BH 6.4kg
- Elevator & Rudder – (3) Corona CS-239HV 4.6kg
33 (!) sheets of Foamboard

To take the wing loading of this very large airplane, a whopping piece of timber was used as the spar. This is removable so that the wings can be unplugged from the center section for transport.

As mentioned in the spec, eight Turnigy D3548/4s were used with some very nice looking four bladed propellors. In total, the plane runs off nine batteries; eight for the motors and one small 2s battery to run the RX and servo gear.

Concerning the flying, Horseman has provided an insight into the airplane's characteristics so we can get a taste of what it's like to pilot something like this ourselves:

"Though the plane is heavy, with the large wing area it glides well and gets some help from ground effect on landing. However it still needs to be brought in under power. In the little stall testing I have done it doesn’t tend to tip stall which surprised me a little as I didn’t leave an under camber on the end of the wing."

You can read more on the Flite Test Forum thread all about the project.

Every build is a challenge in some way, no matter how big or small. Overcoming obstacles to get to an ultimate aim is what it's all about sometimes, and this plane has made it. The final result, decked out in a cargo plane company livery, looks stunning. From all of us here at Flite Test, we think this thing is an incredible achievement and congratulate Horseman3381. Let's all keep making cool things and sharing them!