Douglas XA2D-1 Skyshark

[acegeek9992]

To be fair the general idea did work.

The Brits did similar with the Garnet Armstrong Siddeley Double Mamba with success.

It was just bad gearbox that screwed the T40.

That, and the propeller control system was an absolute crapshot since early Cold War electronics were far from reliable.

 

[drmrhonda580]

Anyone thought about the Westland Wyvern ?

 

[taildragger]

To be fair the general idea did work.

The Brits did similar with the Garnet Armstrong Siddeley Double Mamba with success.

It was just bad gearbox that screwed the T40.

That, and the propeller control system was an absolute crapshot since early Cold War electronics were far from reliable.

How was the propeller control problem significantly more difficult than that faced by other variable-pitch systems of the day? Weren't those systems mostly mechanical mechanisms?

 

[BAROBA]

I noticed that the radar is not in the most optimal position... What was it's use? Because those propellers and most of the engine is blocking its forward view... But also a steel tank hanging beneath it limits is field of view downwards.. It seems also rather small?

 

[aim9xray]

I would suspect that the radar receiver/transmitter unit is located in the belly for quick and convenient access, while the forward-looking antenna is located in the propeller spinner where it enjoys an unobstructed 180 degree (theoretical) forward-looking field of view.

 

[elmayerle]

Regarding Allison and the combining gearbox, remember they did manage to do that successfully with the V3420 when neither Rolls-Royce, Daimler-Benz, nor Daimler-Benz's Japanese licensees managed successful double-engines.

 

[apparition13]

Regarding Allison and the combining gearbox, remember they did manage to do that successfully with the V3420 when neither Rolls-Royce, Daimler-Benz, nor Daimler-Benz's Japanese licensees managed successful double-engines.

The issue was the T40 had over double the horsepower (5500 vs. 2600), and that was just too much for the gearbox design and materials.

 

[robunos]

Regarding Allison and the combining gearbox, remember they did manage to do that successfully with the V3420 when neither Rolls-Royce, Daimler-Benz, nor Daimler-Benz's Japanese licensees managed successful double-engines.

The issue was the T40 had over double the horsepower (5500 vs. 2600), and that was just too much for the gearbox design and materials.

That chimes with what I've read. I'll have to check the references, but AIUI, the output from both turbine units fed into a single 'bull gear', and the metallurgy of the day wasn't up to it . . .

cheers,
Robin.

 

[yahya]

Does anyone have Skyshark's Standard Aircraft Characteristics (SAC) that listed the avionics suite and could share it? Radar's nomenclature is known (AN/APS-19), but what about COM radio and any other electronics this bird may have carried?

 

[iverson]

Does anyone have Skyshark's Standard Aircraft Characteristics (SAC) that listed the avionics suite and could share it? Radar's nomenclature is known (AN/APS-19), but what about COM radio and any other electronics this bird may have carried?

 

[Scott Kenny]

there are scores of PT6T 'twinpacks' that work pretty well too

I'd argue that those are the exception to the rule of twinpacks generally being complete crap.

 

[P-STICKNEY]

I noticed that the radar is not in the most optimal position... What was it's use? Because those propellers and most of the engine is blocking its forward view... But also a steel tank hanging beneath it limits is field of view downwards.. It seems also rather small?

AN/APS-19 doesn't have a 360 degree field of vie.

I noticed that the radar is not in the most optimal position... What was it's use? Because those propellers and most of the engine is blocking its forward view... But also a steel tank hanging beneath it limits is field of view downwards.. It seems also rather small?

Well, the radar's an AN/APS-19, an X-Band surface and air search radar with a gun=aiming mode - It was used in the later night fighter Corsairs and some versions of the Skyraider. Ut used a swept fan beam for surface search and mapping - a 130 deg maximum field of view, and a spiral scan for air search (Intercept Mode). Gun aim was a narrow spiral scan with a max range of 1500'. Maximum surfaace search was about 100 NM, and maximum practical Air Search was about 20 NM. So having the radome and antenna in the front of the spinner didn't degrade anything. (The spinner section ahead of the contraprops was stationary, and Aeroproduct props had hollow hubs, so there was a path to get power and signal up to the antenna.) The electonics boxes weighed in at about 90 lbs (45 kg). In the normal APS-19 installation, the whole package, other than the display unit and control box were carried in a pod that was loaded onto a bomb rack. Overall weight of the pod was about 200 lbs (80 kg), and the electronics took up about 2 cubic ft.

 

[A_Random_Guy]

Here are some of the performance specifications for the A2D under varying loads as listed in Naval Fighters Number Forty Three, Douglas Skyshark by Gerry Markgraf.

 

[Metrallaroja]

Early A2D-1 estimations report 418knots at Sea Level on clean configuration. Impressive!

https://www.generalstaff.org/CDA/Air/A-1/XAD-3_Skyraider_ACP-APR-1947.pdf

High alttitude speed probably underestimated based on 1950 SAC.

 

[F.L.]

Early A2D-1 estimations report 418knots at Sea Level on clean configuration. Impressive!

https://www.generalstaff.org/CDA/Air/A-1/XAD-3_Skyraider_ACP-APR-1947.pdf

High alttitude speed probably underestimated based on 1950 SAC.

The plan is very nice !

 

[ZacYates]

I agree, that looks rather sharp!