Whimsical challenge, assault glider 1940.

[BoKu]

Methinks he be dead, and therefore unavailable.

Sorry, I must have misunderstood the part about "It is the summer of 1940 and..."

At the time, Airspeed Ltd. had designed and were producing Horsa gliders, and I think that Norway could have put Tiltman and his team onto the design of a smaller glider along the lines of what's suggested here.

Edit add: Nevil Shute Norway's autobiography _Slide Rule_ is an absolutely fascinating view into the world of pre-war aeronautic engineering. I rate it right up there with Ann Welch's _Happy to Fly_.

 

[rv7charlie]

There was no 'whimsical challenge' in 1940.

As I said, it's quite likely that the best products for the job, given the tools and materials available at the time, were built. If we're talking about duplicating the effort using today's tools/materials, then we're talking about something else.

Perhaps the OP could clarify his intent.

 

[Riggerrob]

There was no 'whimsical challenge' in 1940.

As I said, it's quite likely that the best products for the job, given the tools and materials available at the time, were built. If we're talking about duplicating the effort using today's tools/materials, then we're talking about something else.

Perhaps the OP could clarify his intent.

Dear rv7charlie,
This whimisical challange is limited to materials and skills that were available during 1940. You can apply more modern thinking and engineering concepts. Aeronautical engineering was much simper back then, so computers or CNC are not needed.
Suggestions may include different tow configurations (e.g. Mistel), different doors, etc.

 

[Riggerrob]

Sorry, I must have misunderstood the part about "It is the summer of 1940 and..."

At the time, Airspeed Ltd. had designed and were producing Horsa gliders, and I think that Norway could have put Tiltman and his team onto the design of a smaller glider along the lines of what's suggested here.

Edit add: Nevil Shute Norway's autobiography _Slide Rule_ is an absolutely fascinating view into the world of pre-war aeronautic engineering. I rate it right up there with Ann Welch's _Happy to Fly_.

Original poster here ...
The first Hotspur flew in November 1940 and the first Horsa flew in Septembert 1941, so the summer of 1940 puts us back at the very beginning of the British Airborne Forces and the struggle to re-invent the wheel without German engineers. This challenge is supposed to produce the first British assault glider ... for a mission similar to the German DFS 230. Britain only raised paratrooper and assault glider forces after the German successes during the summer of 1940.

 

[Hot Wings]

Sorry dear Hot Wings,
But I am restricting this whimsical project to materials and tools that were available in 1940.

Got it! As Spock would say "using stone knives and bear skins".

Where did I last see my slide rule?

 

[berridos]

tow?

 

[rv7charlie]

Dear rv7charlie,
This whimisical challange is limited to materials and skills that were available during 1940. You can apply more modern thing and engineering concepts. Aeronautical engineering was much simper back then, so computers or CNC are not needed.
[snipped]

You do realize that the above is self-contradictory, right?

 

[Riggerrob]

Dear berridos,
Finally!
Some one is thinking!
Yeah!

 

[Hot Wings]

No pictures. CAD is out in 1940 and I can't draw well. Here is my initial thought:

10 soldiers - 40's vintage with gear = 2700 lbs (one is also the pilot)
Airframe structure = 50% of payload = 4000 tow off weight
10#/ft wing loading = 400 ft^2 wing @ 60 ft span = 80 inch chord = 9/1 AR

Strut braced Spratt control wing. 'Pilot' gets to select 2 trim settings - Vx or Vy. Vertical Horizontal stab is fixed. Rudder is linked to stick for roll.
Welded or bolted steel tube structure along the lines of the Aford-a-plane
Fold out wood bulkheads and snap in place wood stringers for fuselage shape - cotton cover zippered or lashed with hemp or raw hide.
Crew gets to lay in cotton hammocks - 2 high x 2 wide x 2 long with the remaining crew member laying under the rear seated 'pilot'. The fuselage covering is fully zippered in place after crew is in.
Cargo is stuffed into cotton pockets (maybe with ply floors) and in the nose (shaped like an SGU 2-22/Cherokee) as needed to tip back on the single main gear to set cg range.

Overall look is a small Zeppelin with a pylon mounted wing and a small bubble on top for the pilot's head.

Parachute used for final phase of landing if needed.

The 60 foot wings come finished and in 2 halves. Assembly is simple by putting pins in place for the Spratt pivots and the struts at the fuselage. 2 control rods. or Teleflex like cables, are the only control hookups needed. The HZ stabs fold down and are pinned in place with struts to the vertical stab/rudder. The fuselage with bulkheads folded and several duffel bags of cotton skin, tools and other assembly materials could be as narrow as 24 inches. The whole thing could fit in a 32ft x 3ft x 6ft tall box with a total shipping weight of 3/4 ton.

 

[Riggerrob]

Dear Hot Wings,
Great independent thinking to simplify shipping and pilot training!

 

[Tiger Tim]

Call me boring, but:

With the Avro Anson being thoroughly service tested and in wide scale production by 1940, I propose we adapt that.

The airframe is largely non-strategic materials (steel tube fuselage truss but otherwise it’s all wood) and the tooling and know-how already exist. The Mk.V had a wood monocoque fuselage but production of those didn’t start until 1941 so we’ll stick to the steel tube. The turret has to go for weight and balance reasons, the engines of course would go and the retractable main gear would be deleted and replaced with a centreline skid. Takeoff would be accomplished from a three wheel dolly as floatplanes sometimes are. For balance reasons a single pilot would be housed in an extended nose section using as much of the de Havilland DH. 84 as possible (windows & frames, instrument panel, controls, seat, etc.) but with its structure adapted to steel tube like the rest of the fuselage.

Towing to the release point may be possible with a Defiant or a Hurricane, the former having available a powered turret to fend off attackers under tow. The latter could carry a couple light bombs to be used to harass an enemy ground position secondary target after glider release as a diversion from the silently approaching glider troops. The glider may also be double towed by a heavy bomber or large transport which itself will carry a complement of paratroops.

In any case, nearly all necessary components are well tested and in full production. If given the go-ahead we can have the first prototype ready to begin testing the week after next.

 

[Hot Wings]

I like the launch dolly idea.
Not too sure I'd like to be one of the sardines in my version, but it is the best way to cut frontal area.

 

[Riggerrob]

Dear Hot Wings,
That is some truly independent thinking about sitting/laying troops in hammocks.
May I suggest that the best position - for hard landings - is sitting, facing aft like most USAF and USN (e.g. Grumman C-3 Greyhound) troop transports. Sling seats only need to be anchored at the top and under the knees. Nylon sling seats are standard on NATO, cold War-vntage helicopters. Aft-facing means that most landing forces shove your butt deeper into the seat, reducing the need for fancy seat-belts.
Since sling seats are only canvas, they can quickly flop aside for quick exits.
I also like your idea of canvas compartments to stow small cargo. In a rush, a soldier can cut them loose with a bayonet.

I survived a King Air crash because initially I was facing aft, with my back leaning against the pilot's seat. Unfortunately, no one else was wearing a seat belt, so they all crushed on top of me. The key point is that I did not flop around the cabin because impact forces forced me deeper towards the pilot's seat.
Now tag-line seat-belts are installed in many skydiving jump-planes. They are standard on (PAC XL 750 and Quest Kodiak and retrofitted to many Cessnas). They were invented by Jack Hooker (Hooker Harnesses). Hooker tag-lines became popular after two fatal jump-plane crashes in 1992. The bottom ends clip to cargo rings or seat-belt anchors on the cabin floor. One end of the belt slips around the hip joint of a parachute harness, then clips back into the bottom piece.
These days, most skydivers sit on bob-sled style benches, facing aft ... towards the door.

 

[Hot Wings]

Now tag-line seat-belts are installed in many skydiving jump-planes.

I considered the aft facing seat for the reasons you mentioned. But in the end they were rejected due to aerodynamic reasons - reducing drag for good glide ratio.
After all this is for war use back when soldiers were less pampered than we would consider acceptable today. A rough foot first arrival at the desired landing spot might be better than an aft facing one at a less than desirable location?
A system of belts/harnesses attached to shock absorbing lanyards similar to current fall protection harness systems might work with the prone 'cargo'?

 

[Aesquire]

My First thought...

Boxy fuselage, under inflatable Rogallo wing.


I like rearward facing seats for the crash, I mean landing, and most of the passengers will have empty stomachs by the time you get across the Channel. ( as I recall from the old station wagons with rear facing seats )

Unfortunately, 4 to 1, or with some refinement, 6 to 1, is all I can promise.

And Rubber is a strategic material, especially In England in 1940. But you can load the uninflated wing into the fuselage. Rigid spars, laminated wood, could also be used, instead of rubber bladders

But On further thought, the ram air chute designs would be even easier to control, and get better than 6 to 1, although the 150 mph tow speed is an issue.

 

[Aesquire]

Off topic, but I had a terrifying thought, how the English could have invaded France before D-Day with far less build up of landing craft, but the casualty rate?

 

[Riggerrob]

Dear Aesquire,
Glad the hear that you are thinking outside the (Waco) box.

Inventors were sketching Rogallo-like gliders as early as the 1930s, but Francis Rogallo did not perfect the concept until the 196os. As soon as Rogallo patented the concept, the new sport of hang gliding adopted the configuration. Many thousands of Rogallo hang gliders have flown.

The good news is that you do not need stiff leading edge tubes to fly a Rogallo canopy. Once inflated, underside air pressure makes them fly fine.

During the 1970s, a few parachute manufacturers started experimenting with Rogallo canopies in search of flatter glide than Para-Commanders (complex rounds). Their biggest problem was hard openings, a problem that Carl Yarbanet eventually solved by re-inventing the slider.

Irvin was the first with their Delta II. I made four jumps on a Delta II, but .... it opened too hard. Later I jumped a Paradactyl and rather enjoyed it. Its 2 -> 1 glide ratio was almost as good as early ram-airs and openings were reasonable with a slider. During the early 1970s, Paradactyl was the smallest packing sport parachute.

I still have a PZ_81 Rogallo reserve parachute and a Telka Rogallo reserve parachute in my personal collection.

 

[Aesquire]

I jumped the pre-slider version of the Paradactyl, & the opening was... memorable.
Fun though. I liked it.

Francis Rogallo's kite patent was for a "soft" design without a rigid frame.
I recently discovered the kiteboard/snowkite world that evolved while I wasn't looking.
There are 2 parallel design threads, ram air kites with tech crossover from paragliding, and leading edge inflatable kites with a range of aspect ratio and # of stiffening struts. Dacron & other synthetic materials, with polyurethane inner tubes.

There are videos of snow kites ( wearing skis or snowboard, and using a kite to go Up a mountain, or across fields & frozen lakes ) launching off mountains and gliding down. The "funny" part, is the harness/controls are designed to be used standing, not flying, so they glide with the "pilot" facing opposite direction of travel.

I'm tempted to get an appropriate sized kite and convert it to paragliding controls & harness, but the "regular" paragliders are so good now, it would just be for the learning experience. Otoh, a 21sq. Meter wing might be a hoot to soar the local training hill.

 

[Aesquire]

Back to the OP, soft wings, fabric and lines, would be well within the tech capability of 1940, but the tow plane would need to be capable of slow flight with excess power to climb/tow. And the speed is too low to meet spec. At least, I don't know if 150 knots is achievable.

Remember the Ancient Aliens myth/fad? The Plain of Nazca figures? While flight isn't needed to make Such things, ( I make acre sized yard mazes in my back yard, so... ) The Aztecs could have made hot air balloons, man carrying kites, and hang gliders with their daily technologies.

NASA Paresev - Wikipedia

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Ryan XV-8 - Wikipedia

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