Telescoping wings

[riggerrob]

A few engineers have proposed telescoping wings. Fewer mockups have been displayed, but only a handful of prototypes flew, none entering production.

Circa 1920, Terrasaurian proposed a flying submarine with telescopic, biplane wings. A few sketches were published in an English-language magazine.

Most of these concepts were proposed between World War 1 and WW2, in both France and Italy.
Gordou Leseurre built wind tunnel models in France.
Russian-born engineer Ivan Makhonine, MAK-10 and MAK-123. The MAK-10 prototype first flew 1 August 1931 in France. It was a conventional, cantilever, low-wing monoplane with fixed, spatted landing gear and two cockpits behing a Lorraine W engine. After 4 years of test flights, it was re-engined with an 800 horsepower Gnome and re-named MAK-101. The later MAK-123 prototype had a radial engine, a long canopy and Stormovik-style retractable landing gear. The MAK-123 was photographed painted in Luftwaffe insignia.

During WW2, Messerschmitt proposed a telescopoic wing version of their 328 interceptor powered by a pair of pulse jets. The telescopic wing Me 238 version was intended to launch from submarines or railways. But never seems to have gotten off Messerschmitt's drawing board. Our Justo Miranda has drawn a few speculative sketches of the telescopic Me. 328.

Post WW2, an American named William Horton built a "Horton Wingless" prototype based upon a much-modified Cessna T-50, UC-78 Bobcat/Crane, light twin. The Wingless was basically a low aspect-ratio plank with outer wing panels that telescoped out for landing and take-off. Its pair of 225 horsepower, Jacobs, radial engines drove two propellers mounted on extension shafts long enough to get them forward of the swept leading edge. A painting of Horton's creation graced the cover of Science and Mechanics magazine February 1951. The prototype demonstrated impressive performance the few times it flew. Another version of the story has the prototype powered by a pair of P&W R-985 radial engines. The Wingless prototype was built in a three-way partnership with Horton, Howard Hughes and Harlow Curtice of General Motors fame. When the partners fell out, Horton was jailed on allegations of stock market fraud. The prototype was sent to Orange County Airport where it was deliberately burned.

During August 1971, the Aquajet, amphibian, business jet concept made the cover of Mechanics Illustrated, though I doubt if they ever built a prototype. Dr. G. Leonard Gioia hired engineers Norris Switzer and John Willerton.
Motocar has published a cutaway of the similar-looking Skyshark over on the artwork forum.
aka. Ominionics Dolphinair patents show a similar high-winged amphibian.

Gevers was a bit more conservative, proposing a light business twin with twin, flat-6, air-cooled, Lycoming, piston engines. Circa 1999 I glanced at the Gevers Genesis seaplane mockup in Arlington, Washington. But I doubt if they ever built a prototype.

 

[Zoo Tycoon]

Akaflieg Stuttgart fs29 - Wikipedia

en.m.wikipedia.org

This flew, unsure how successful but it was flown between 1975 to 1997.

 

[avion ancien]

You've omitted to mention the Gérin Varivols.

 

[Silencer1]

A few engineers have proposed telescoping wings. Fewer mockups have been displayed, but only a handful of prototypes flew, none entering production.

Soviet engineer Bakshayeff made prototype of LIG-7 aircraft

and few projects of more advanced types, including RK-I fighter

 

[riggerrob]

cher avion ancien,

How could I forget the Gerin Varivol when I never heard of it before?
Hah!
Hah!
I started this thread in hopes that other contributors would help fill gaps in my knowledge.
Now you have forced me to research both of Jacques Gerin's Varivol airplanes.

Gerin built two Varivol prototypes - in France - during the 1930s.

The first was an odd-looking biplane with reverse sesquiplane wings, meaning that the top wing had a shorter span than the lower wing Lower wing span remained fixed at 11.77 metres in both take-off and cruise configurations. These "wings" were little more than streamlined main struts, supported by a single inter-plane strut and a few wires. For landings and take-offs, extra wing panels slid out of the fuselage, along the trailing edges of both top and bottom wings. The extended panels had longer chords than fixed wings. Top wing area increased from 6.3 square metres to 26 square metres when electric motors extended flexible wing panels. Wing camber could also be changed in flight.
Holy over-sized ailerons Batman!
The Varivol biplane fuselage started with an un-cowled, 230 horsepower, Salmson radial engine turning a 2-bladed propeller. The bulky fuselage completely filled the gap between the top and bottom wings. A single pilot sat in an open cockpit aft of the wings. The fuselage got even deeper the farther aft it continued, swelling to the full height of the (full sized) rudder. The horizontal tail lay on top of the aft fuselage, making a T-tail with only the tiniest of vertical fins. Some photos show fixed, tail-wheel undercarriage while others show fixed nose-wheel undercarriage.
The biplane was wind-tunnel tested at Chalais-Meudon. The Varivol biplane flew from March 1931 until November 1931 when it was destroyed in a fatal crash.

Gerin's second Varivol V.6E was a much prettier, mid-wing, cantilever monoplane that resembled a Caudron racer in silhouette. It was powered by a 6-cylinder, air-cooled, inverted inline engine. The single cockpit was aft of the wings and enclosed in a Plexiglas canopy. The wings were based on wooden box spars, around which the aerodynamic outer wing panels slid in or out to increase span. Outer wing planform remained constant. Sliding outer panels outboard almost doubled wing span Broad, constant-chord inner wing panels extended from the fuselage. Inner (flexible) wing chord was more than double that of slightly tapered out wings panels. Construction appears to be mostly wood.
Construction started in 1938, but was not completed until 1946. It was wind-tunnel tested in 1946.
Internet accounts vary as to whether the monoplane ever flew.
The monoplane prototype languished in a barn for 50 years before being restored and displayed at the Musee Regional de l'Air in Anger, France. A few plywood panels have been replaced by Plexiglas that allows visitors to inspect the inside of the fuselage.

 

[Schneiderman]

Never constructed but in 1943 George Miles submitted a patent application for a telescoping and twisting wing tip. GB565634A

 

[Justo Miranda]

Me 328

 

[avion ancien]

cher avion ancien,

How could I forget the Gerin Varivol when I never heard of it before?
Hah!
Hah!
I started this thread in hopes that other contributors would help fill gaps in my knowledge.
Now you have forced me to research both of Jacques Gerin's Varivol airplanes.

Gerin built two Varivol prototypes - in France - during the 1930s.

The first was an odd-looking biplane with reverse sesquiplane wings, meaning that the top wing had a shorter span than the lower wing Lower wing span remained fixed at 11.77 metres in both take-off and cruise configurations. These "wings" were little more than streamlined main struts, supported by a single inter-plane strut and a few wires. For landings and take-offs, extra wing panels slid out of the fuselage, along the trailing edges of both top and bottom wings. The extended panels had longer chords than fixed wings. Top wing area increased from 26 square metres. 6.3 square metres to 26 square metres when electric motors extended flexible wing panels. Wing camber could also be changed in flight. Holy over-sized ailerons Batman!
The Varivol biplane fuselage started with an un-cowled, 230 horsepower, Salmson radial engine turning a 2-bladed propeller. The bulky fuselage completely filled the gap between the top and bottom wings. A single pilot sat in an open cockpit aft of the wings. It landed on conventional, fixed, wire-braced tail-wheel undercarriage. The fuselage got even deeper the farther aft it continued, swelling to the full height of the rudder. The horizontal tail lay on top of the aft fuselage, making a T-tail with only the tiniest of vertical fins. Some photos show tail wheel undercarriage while others show a nose-wheel undercarriage.
The biplane was wind-tunnel tested at Chalais-Meudon. The Varivol biplane flew from March 1931 until November 1931 when it was destroyed in a fatal crash.

Gerin's second Varivol V.6E was a much prettier, mid-wing, cantilever monoplane that resembled a Caudron racer in silhouette. It was powered by a 6-cylinder, air-cooled, inverted inline engine. The single cockpit was aft of the wings and enclosed in a Plexiglas canopy. The low wings were based on wooden box spars, around which the aerodynamic outer wing panels slid in or out to increase span. Wing chord remained constant. Sliding outer panels almost doubled wing span Broad, constant-chord inner wing panels extended from the fuselage. Inner (flexible) wing chord was more than double that of slightly tapered out wings panels. Construction appears to be mostly wood.
Construction started in 1938, but was not completed until 1946. It was wind-tunnel tested in 1946.
Internet accounts vary as to whether the monoplane ever flew. The prototype languished in a barn for 50 years before being restored and displayed at the Musee Regional de l'Air in Anger, France. A few plywood panels have been replaced by Plexiglas that allows visitors to inspect the inside of the fuselage.

Now isn't it so much more fun to learn about these obscurities by reseaching them yourself rather that letting others do it for you!

 

[riggerrob]

Yes cher avion ancien,

Researching obscure airplanes is fun, but I was hoping that another contributor would download a few photographs.
Either that or I will have to learn how to down-load photos. .. another adventure ....

 

[TomcatViP]

Le Fana made a report on both design from Varivol with extensive pictures somewhat around 10 years ago.
See also here:

https://www.secretprojects.co.uk/threads/jacques-g%C3%A9rins-%C2%AB-varivol-%C2%BB-projects.2794/

 

[shedofdread]

Whilst a model and certainly not pre-war, the 'Tele-F' F3B class glider by Ralf Decker quite successfully used telescopic wings.

View: https://www.youtube.com/watch?v=WLlbWPg5UlU


To withstand the stresses of an F3B winch launch and the subsequent flight loads, it would have had to be a robust and reliably engineered system.

Edit- just thought; perhaps this should be moved to 'Aerospace' as it seems to be a general telescoping discussion? Just a thought...

 

[Silencer1]

We already has quite informative topic on Gerin Varivol

https://www.secretprojects.co.uk/threads/jacques-g%C3%A9rins-%C2%AB-varivol-%C2%BB-projects.2794/

 

[Johnbr]

 

[TomcatViP]

We already has quite informative topic on Gerin Varivol

https://www.secretprojects.co.uk/threads/jacques-g%C3%A9rins-%C2%AB-varivol-%C2%BB-projects.2794/

2 post above

 

[Silencer1]

2 post above

Thanks, TomcatVIP!
My bad.

Perhaps, addition of the Varivol' telescoping airfoyle' image would enchance the tread?
As at least two different appoaches to the changing of wing's lifting force could be presented simultaneously.

 

[TomcatViP]

Feel free

 

[Justo Miranda]

View attachment 638593View attachment 638594

Please see Horton airplane https://www.secretprojects.co.uk/threads/william-hortons-wingless-designs.5996/

 

[riggerrob]

Guiseppe Bellanca also filed a USA patent for a telescoping wing, during the 1930s, but we doubt if he ever built a mock-up.

 

[hesham]

Hi,

I never heard about this designer before and his system was so weird ?.

 

[Apophenia]

Not so weird. The article notes Ministere de l'Air trials of "l'avion Makhonine" (Ivan Makhonin) in 1931. The telescoping wing concept is essentially similar.

 

[avion ancien]

..... and then, of course, there were the Gérin varivols, which followed broadly the same principle and also are mentioned in the article.

 

[riggerrob]

Dear moderators,
Please link this thread with the larger thread on telescoping wings.

Done, thanks for the clue !

 

[Aerohydro]

​

For your information, and your entertainment, here's another telescoping wing design; the 1938 Ellingston Special.

Designed by Con Ellingston of Montana, the craft featured not only a retractable wing, but also a retractable undercarriage. Quite a compact design, its wingspan could vary between 25 ft and 32 ft, allowing it to fly as slowly as 40 mph or as fast at 110 mph.

Although the Special garnered some coverage in the American aviation press at the time, the craft seems to have been largely forgotten about since. Here are some articles, etc, about the Special:

"Popular Aviation" - Dec 1939 - page 53 ff​

​

"Aviation Week" - November 1938 - pg 45​

​

"EAA Vintage Airplane" - March 1996 - pages 26-27​

​

Airwar.ru - Ellingston Special (in English)​

​

There was also an illustrated article which had appeared in the July 1938 issue of "Western Flying", but unfortunately I haven't been able to track down a copy of that.

Cheers,
Paul

 

[Justo Miranda]

Hi

 

[Tonton-42]

Formula promised to a bright future that varies in scope !..

 

[Magman]

Circa 1905ish some folks in Buffalo,NY proposed telescoping wings as a method of roll control. Coincidentally; that was where the Wright/Curtiss “Aileron Lawsuit” went to court.
I do recall a picture but not the details.

 

[publiusr]

With origami/kirigami, you might get inflated wings at the ends. Harder inflated inner struts inside a more gently inflated wing. Maybe with ram-air…the wings get stiffer in a dive…use the air against itself to deploy maybe.

 

[Cy-27]

A little bit more on the Soviet aircraft in post #4 from Silencer1. Attached are three-views of the Bakshayev designs for the LIG-7 and RK-1 (with basic measurements). Both of the drawings are time-stamped 2004 so I would think it highly likely they are from an early Shavrov volume.

In the book Unflown Wings (Gordon/Komissarov (ISBN 978-1-90653-734-0), pages 439-441, there are images and brief descriptions of Bakshayev’s work at Leningradskiy Institute GVF (the LIG designation) and his RK designs. By the way, RK denoted Razdvizhnoye Krylo or Telescopic Wings.