Frank A. Dobson Tilt-Rotor Delta-Wing

[Stingray]

From Popular Mechanics, June 1954:

Of all the tilting-rotor-type designs, one of the most unique comes from California. At North American Aviation (which hasn't anything to do with the project), research engineer Frank A. Dobson and some fellow workers have developed a mosquitolike little delta-wing craft with two vertical fins and a pair of 16-foot three-bladed, contrarotating propellers on a single hub that juts from the nose. In this position, the tiny craft is a fast-flying (187 miles per hour) triangular affair powered by twin McCulloch engines whipping up 70 horsepower each. The plane carries two passengers and Dobson envisions it as a back-yard family craft or a military liaison vehicle.

When Pop climbs in to take off, the craft sits on a pair of skids under its low aft end and swivel wheels under the nose. The hinged nose shaft is pointed skyward, with stacked rotors whirling in opposite directions. If Junior is hopping around, the thing won't take off but will pivot around on its skids until he climbs into the seat and the center of gravity is established beneath the rotor. Then, up she goes, nose high, like a helicopter. At proper altitude, the nose hub goes down and the craft zooms away at a 170-mile-per-hour cruising speed. To land, the process is reversed, and the craft helicopters to earth at a maximum forward air speed of 20 miles per hour.

At last report, Dobson and his friends were building a prototype. If it is successful, he expects to try a military type of jet machine that he believes will do 700 miles per hour.

 

[hesham]

Hi,

http://archive.aviationweek.com/image/spread/19530803/14/2

 

[Boxman]

Silent footage of the Franklin Dobson Convertiplane recently posted (3-Aug-2020) by Periscope Film to YouTube. Here's the description of the footage provided by Periscope Film:

This short, silent film from the collection of Jeff Vilencia, shows the design and construction of the Dobson Convertiplane built by Franklin A. Dobson of Newport Beach, California. It likely dates to the early 1950s. Frank Dobson was an inventor with many ideas who also built and/or patented an anti-submarine warfare device known as "SCAT", toys, and started a business selling hovercraft kits. At 1:15, one of his toys is shown -- a flying wing aircraft with similarities in design to the Convertiplane, which could take off like a helicopter and fly like a plane. Dobson's designs are shown in Aviation Week at 2:30, and People Magazine at 3:00. Construction of a prototype follows including at 3:56, construction of a geared hub, the airframe at 4:00, engine 5:20, and more. At 8:29 a prototype similar in design to the flying toy seen earlier is shown on the ground. At 10:02 what appear to be counter-rotating props are shown at the front of the aircraft. At 10:57 a ground test is shown of the counter-rotating propellers in a helicopter configuration. The film ends with tantalizing shots of a much more elaborate prototype being painted and at 12:23 displayed on the runway. At 12:49 the rotor is shifted from helicopter to airplane configuration. It's unclear if this craft ever flew. FAA records indicate it was tail N89P, first registered in 1956.

YouTube - Periscope Film: "FRANKLIN DOBSON CONVERTIPLANE EXPERIMENTAL VTOL AIRCRAFT (SILENT FILM) 15384"

 

[VTOLicious]

Interesting video and apparently some good engineering. But I have the gut feeling it either didn't hover well or crashed on the attempt to transition to wingborne flight.

 

[FXXII]

It seems to me, that the centre of gravity is way aft of the liftvector of the rotors, so how to keep equilibrium? Nonetheless, it looks a very fine project.

 

[TomcatViP]

@FXXII : Extract from introducing post:

When Pop climbs in to take off, the craft sits on a pair of skids under its low aft end and swivel wheels under the nose. The hinged nose shaft is pointed skyward, with stacked rotors whirling in opposite directions. If Junior is hopping around, the thing won't take off but will pivot around on its skids until he climbs into the seat and the center of gravity is established beneath the rotor.

It's the definition per se of the personal plane

Great design. Notice the swiveling rotor hub similar to our modern Valor (he could have gone with the entire engine assembly swiveling a la Osprey but put most of his effort in that design... Hats down).

 

[FXXII]

That's my point, the seat is halfway the side window of the prototype (around 10.15 into the film), the center of gravity of the empty plane is probably not under the rotors, because a large part of the aircraft and its tail and engine is located aft of the rotors. So seating yourself in the seat puts the CoG even further aft. I think the aircraft will not pivot aroound its skids, but salto backwards. Are there any footage or stills of this aircraft in flight?

 

[TomcatViP]

IMOHO, reading the bits here and watching this excellent video, I understand that the landing gear is as well articulated. Hence when the rotor pulls upward (the moment perpendicular to the shaft axis is unrestricted) the CG aligns itself with the rotor hub (the fuselage slide slightly forward and pitch upward) and off you go.

The problem they might have is not having direct control: everything had to be articulated before you get a perfect balance.

My 2 cents.

 

[yasotay]

I have to wonder, with today's technology, if that might not make for a decent medium UAV platform. Runway independent, probably enough SWAP for a fair sensor package, and you can tow it. I imagine that the lack of stability augmentation might have made it a tough VTOL, but I cannot see why it would not have worked as a VSTOL platform.

 

[TomcatViP]

Yes it does. But the ctrls sensors have to be placed wisely (not as done traditionally ).

 

[Richard N]

View: https://www.youtube.com/watch?v=Iv4ugNUXzrg&list=PLAqZ0jsH2nEJF67Sn53J9qEjkMcXfbWfx&index=2

 

[hesham]

A patent for him,with AW article.

 

[eraygor]

I’m trying to find Frank Dobsons family. I have a ton of his personal belongings and most of it is the original plans and information on his creations. I purchased a storage unit in Orange County back in 2013 and have been trying to locate the family to get it back to them. Any help would be greatly appreciated.

 

[publiusr]

That’s noble of you—-sets you apart from vultures who make a living off of someone else’s death/poverty. I used to go to estate sales but my conscience got to me.

 

[yasotay]

Might I recommend checking with the Exprimental Aircraft Association, or the Vertical Flight Society for a start. Other professional aerospace.organizations might be able to assist.
Glad to see someone has secured another small but wonderful piece of aviation history.

 

[hesham]

I’m trying to find Frank Dobsons family. I have a ton of his personal belongings and most of it is the original plans and information on his creations. I purchased a storage unit in Orange County back in 2013 and have been trying to locate the family to get it back to them. Any help would be greatly appreciated.

Welcome aboard Eraygor,

please can you send his creations in aviation here,we want to know
more about his work.

 

[UpForce]

I purchased a storage unit in Orange County back in 2013 and have been trying to locate the family to get it back to them.

I hope you succeed. Failing that, donating to a reputable museum is an option.

 

[Cswanson]

Is this the Frank Dobson who lived in Whittier, California? If it was, I might be able to help.

 

[Cswanson]

I’m trying to find Frank Dobsons family. I have a ton of his personal belongings and most of it is the original plans and information on his creations. I purchased a storage unit in Orange County back in 2013 and have been trying to locate the family to get it back to them. Any help would be greatly appreciated.

I'm new to this forum and system. I tried to respond in another context but I'm not sure where it went. I think that i knew the Dobson family when they lived in Whittier, California in the mid-50s. My friend, Perry Dobson, and I even helped make a part for his planned plane. I think I could help find Perry.

 

[Cswanson]

I purchased a storage unit in Orange County back in 2013 and have been trying to locate the family to get it back to them.

I hope you succeed. Failing that, donating to a reputable museum is an option.

Check out the obituary for Mona Francis Dobson in the Whittier News.

 

[hesham]

Welcome aboard Cswanson,

and if you have any materials or projects for him,you can send them here.

 

[Cswanson]

This, combined with my earlier comments should be a pretty good lead for finding a connection to Frank Dobson. I think he is the person you are looking for but I don't know why the family isn't interested in the contents of the storage unit that you bought.