Earliest possible LAPES?

What is the earliest date a Low Altitude Parachute Extraction System could be perfected?
OTL LAPES was first used during the Siege of Khe Sanh 1966. During that siege, USAF C-130 Hercules delivered a many thousands of rounds of artillery ammo, allowing USMC defenders to succeed when the French Foreign Legion failed a decade earlier at Diem Bien Phu.

Would LAPES have been practical before the invention of tail gates (Budd Conestoga, Fairchild Flying Boxcar, Fairchild Husky, Lockheed C-130 Hercules, etc?

Would LAPES have been practical with all the extra aircraft WALLIES had during the summer of 1944? Would Spitfires, Thunderbolts, Halifaxes, etc. have been able to deliver sufficient tonnage around the bottle-necked Normandy beaches?

Would LAPES have helped the Poles during the Battle of Falaise Gap (August 1944)?
Would LAPES have helped Polish ... British paratroopers at Arnhem (September 1944)?
 
Would Spitfires, Thunderbolts, Halifaxes, etc. have been able to deliver sufficient tonnage around the bottle-necked Normandy beaches?

I'm not sure Spitfires and Thunderbolts are good platforms for a LAPES delivery. They don't come fitted as standard with a rear cargo ramp.
 
I think the rear cargo ramp may be the prerequisite for LAPES, so maybe the question is could a the rear ramp design be built with WW2 technology?
 
some german planes (gotha 244 and arado 232) (1941)
go-244:
Go244-15f-s.jpg

Ar-232:
ar232-003.jpg

US: fairchild C-82/ C-119 (1944)

300px-C82_Packet.jpg
 
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Germans had the trappoklappe rear ramp on Ju-252 and Ju-290 which could deliver parachute cargo or parachute troops who slid down the ramp face first. Whoo-wee.
 
The rear cargo ramp was necessary to deliver any large sized cargo by LAPES. Another factor was the climb after dropping the LAPES package. A high power to weight ratio was necessary to get the aircraft away from the ground before you run out of landing area and get into conflict with surrounding terrain, especially at forward airstrips. Most WWII cargo aircraft didn't have the necessary power and this was not really developed until jet/turbine engines were developed. The C-119 didn't really have this power but the C-130 did.

I can tell you this from personal experience. I'm probably the only AH.com member who has flown on both. :)
 

trurle

Banned
The rear cargo ramp was necessary to deliver any large sized cargo by LAPES. Another factor was the climb after dropping the LAPES package. A high power to weight ratio was necessary to get the aircraft away from the ground before you run out of landing area and get into conflict with surrounding terrain, especially at forward airstrips. Most WWII cargo aircraft didn't have the necessary power and this was not really developed until jet/turbine engines were developed. The C-119 didn't really have this power but the C-130 did.

I can tell you this from personal experience. I'm probably the only AH.com member who has flown on both. :)

The question in this case is mostly about climb rate, not the power/weight. If C-119 fails, C-47 may do the trick as his climb rate was about 10 m/s - similar to C-130. Also, stall speed is lower compared to C-130, so C-47 actually can climb at higher angle. Lack of rear door make a problem though. But i remember Lisunov Li-2 (from the same DC-3 family as C-47) was able to carry 1 ton of bombs under wings. Replacing the bombs with the LAPES pods (instead of LAPES pallets) may be ok. The aerodynamics of pods need not to be overly perfected, because the cruise speed would be just about 250 km/h.

Such development was possible if some people during WWII come to idea of towed gliders simplification. Or the hybrid of towed glider and parasitic fighter concepts stripped of all non-essential parts.

Take glider > Simplify undercarriage > Add drogue chute > Specify very low drop height > Remove pilot > Remove controlled aerodynamic surfaces > Make suspension integral with fuselage > Make under-wing glider version > Remove all wings and stabilizers > Simplify design = LAPES pod

With may be ~400kg payload per pod, WWII-era LAPES will be not terribly efficient delivery method. But you can still drop weapons up to may be 75mm M116 howitzer (in 2 loads) - or a lot of ammunition.
 

trurle

Banned
Would Spitfires, Thunderbolts, Halifaxes, etc. have been able to deliver sufficient tonnage around the bottle-necked Normandy beaches?
If surplus C-47 would be available, it may be possible.
Would LAPES have helped the Poles during the Battle of Falaise Gap (August 1944)?
I doubt it was a reason to use a LAPES. The Polish 1st armoured divsion was never trapped, right?
Would LAPES have helped Polish ... British paratroopers at Arnhem (September 1944)?
No. The problem was poor communication and featureless terrain, not the size of the landing zone.
 
Good points about developing LAPES from assault gliders.
OTL since LAPES never drop high enough to worry about vertical rate of descent, the parachutes only BRAKE the load by gradually reducing horizontal velocity. Braking parachutes were first used on DFS assault gliders early in WW2.
After WW2, hundreds of Germany's best aeronautical engineers (e.g. Theo Knacke) moved to the USA (Operation Paperclip) and the USSR. During the Cold War, they perfected braking parachutes for early jet bombers and Century series fighters to reduce runway length requirements for landing. Even the first batch of Learjets needed braking chutes to satisfy runway length certification.
Circa 1960, US engineers back-loaded braking chute technology for air assault.

Maybe braking chute technology was not perfected until 1960????

As needing a tail ramp .... C-47s were built with under-wing bomb racks specifically designed to drop cargo cylinders to para-troopers. Simple matter to hang braking chutes off the back end and drop them from lower altitudes.

As for needing tail ramps, the first cargo plane with a tail ramp was the Budd Conestoga. The prototype Conestoga first flew .... and it entered USN service in ........

Yes! Poles were surrounded during the Battle of Falaise Gap. They tried to "cork the bottle" created by Canadian troops advancing g from the North and American troops advancing from the South. Trapped Nazis despearately tried to escape by over-running the Polish "cork." Poles stubbornly defended a hill they named "the Mace." Poles advanced too far during the Battle of Falaise Gap. Poles advanced beyond their (British) supply lines as they tried to prevent all the Nazis remaining in Normandy from escaping. Poles ran so low on linked machine gun ammunition that Spitfires dropped ammo from low altitude onto the "Mace" (Hill held by Poles).

As for piston-pounding C-119s not having sufficient climb rate to exit steep mountain valleys - after dropping cargo - yes!
C-130 had a far better climb angle for delivering cargo to mountain valleys.

But the OP asked about "earliest possible LAPES" ? Let's limit our conversation to LAPESing cargo into fields with clear approaches.
 
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