Burnelli UB-20

[Mark Nankivil]

Greetings All -

A recent photo collection donation to our Museum had this photo in the mix. It appears to be the Burnelli UB-20. Anyone able to confirm that?

Enjoy the Day! Mark

 

[richard]

Aerofiles confirms :

http://www.aerofiles.com/_burnelli.html

 

[theponja]

Thanks for the picture!!!

I'm trying to model this aircraft and this is going to be very helpful.

Anyone has a 3d view? I've only pictures until now.

 

[Retrofit]

I think it is a 3V of the UB-20 (but the model reference is not clearly mentioned).
Source: Flugsport (dated unkown)

 

[theponja]

Thanks Retrofit. The 3d view seems of the UB-20 one interesting thing: the cockpit in the picture looks different than the 3d view. I can't found any another picture of the cockpit so maybe I've to modify this in the model.

 

[Stargazer]

Here is all the pics of the UB-20 I have on my hard disk:

 

[Stargazer]

And a couple more:

 

[Nik]

Seems a shame that the design never caught on-- The *original* wide-body hauler !!

 

[theponja]

Thanks a lot stargazer. This is very helpful.

 

[Boxman]

Photo of the Uppercu-Burnelli UB-20 recently posted at the San Diego Air & Space Museum (SDASM) Archive's Flickr photostream (link to the largest version of the photo below).

http://www.flickr.com/photos/sdasmarchives/6335818386/in/photostream

 

[taildragger]

Does anyone know if the ability to carry underslung cargo was a designed-in feature or some sort of stunt? I designed-in, that would explain what looks like an unusally nose-high stance on the ground. I wonder if a Burnelli design would be a good choice for a capability like this since one of the intended advantages of the layout is the lift generated by the fuselage. Slung cargo would seem to compromise this by changing the airflow under the lifting fuselage, thereby imposing a greater penalty on the Burnelli design than it if a cargo were slung underneath a conventional non-lifting fuselage.

 

[Motocar]

Quick AI Response

Transporting a suspended load beneath the Burnelli UB-20's fuselage was primarily a publicity and promotional stunt, though it was facilitated by a high landing-gear stance that served both practical technical purposes and Vincent Burnelli's own desire to demonstrate his aircraft's payload capacity.

The truth behind the suspended load

In 1934, a Burnelli UB-20 performed a famous promotional flight for the Sun Oil Company, carrying a Ford automobile suspended directly beneath the fuselage, positioned right between the fixed landing gear struts.

* Capacity demonstration: Burnelli's "lifting body" fuselage design allowed for enormous internal volume and high weight-carrying capacity. Carrying a car externally was not the standard or commercial mode of operation, but rather a striking publicity maneuver designed to impress the public and the industry.

* Precedent: Vincent Burnelli had already staged a similar spectacle in 1924 with his earlier model (the Remington-Burnelli RB-2) by placing a car inside the cabin for promotional purposes.

* High stance: The fuselage's significant ground clearance was not designed specifically for hanging loads, but rather to accommodate the lifting body's massive cross-section, house the fixed landing gear's steel framework, and ensure adequate ground clearance for the main propellers.

Aerodynamic trade-off: Lifting body vs. External load

Your aerodynamic analysis is correct: carrying an external load is substantially more detrimental to a Burnelli design than to a conventional, non-lifting fuselage.

1. Alteration of underside airflow

* On a conventional aircraft, the fuselage primarily generates drag and little to no lift.

* In the Burnelli concept, the fuselage is shaped like an airfoil. To generate lift, there must be a clean pressure gradient between the underside (lower surface) and the upper surface.

* Attaching a bulky, non-aerodynamic object (such as an automobile) directly to the underside of the fuselage disrupts laminar flow along the lower surface, creates massive turbulence, and causes a direct loss of fuselage-generated lift, in addition to drastically increasing parasitic drag.

2. Severity of the penalty

| Design | Effect of External Suspended Load | Overall Impact |

|---|---|---|

| Conventional Fuselage | Adds aerodynamic drag and weight, but the wing maintains clean airflow and lift efficiency. | Moderate |

| Burnelli Design | Adds aerodynamic drag and weight, and also negates the lifting capability of the fuselage itself—which accounts for 25% to 30% of the total lifting surface area. | Critical |

Although the UB-20 had ample power (two 750 hp Packard V-12 engines) to compensate for the loss during short demonstration flights, the suspended load undermined the core benefit of the Burnelli configuration, demonstrating that the move was merely a publicity stunt.

To see images of the actual UB-20 design in flight and how the car was mounted beneath the aircraft's belly for the promotional campaign, you can watch this historical footage from the era:

Uppercu-Burnelli UB-20 transporting a car (1934)

This video shows the moment the Burnelli UB-20 takes off with the Ford automobile mounted between the landing gear struts, serving as a visual record of the publicity event.