Lockheed YP-24/Consolidated P-30

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Zipper730

Chief Master Sergeant
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Nov 9, 2015
From what I remember the YP-24 was based upon a transport called the Altair, which was built to sport specifications.

I'm curious if sport specifications were the same as fighter ones?
 
wuzak said:
No. It wasn't built to a "sport" specification
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I remember a similar description used before, though I'm not sure if it applied to the United States.

What I'm interested in was, since the P-24/P-30 was based on a small transport plane
  • What g-load was the Lockheed Altair designed around?
  • What g-load was the Lockheed/Consolidated P-24/P-30 designed for?
  • What was the typical g-load requirements that fighters of the era?
 
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You are in an era when things may have been in a state of flux as far as government regulations were concerned.

The Lockheed Sirius was ATC #300 on 3-14-30 and the first ATC (airworthiness type certificate) had been issued in March of 1927.

The Books I have show no mention of the Lockheed Altair (basically a Sirius with retractable landing gear?) having a regular ATC, at least 3 had a group 2 certificate.
Group 2 was for aircraft with modifications or a small number of prototypes. However some aircraft with full ATCs often failed to find much of a market and were built in very small quantities so things get a bit blurred.

Please note the certification date for the Sirius was only about 1 year months before the Fokker tri-motor crash that killed Knute Rockne and result in, according to WIki

"...sweeping changes to airliner design, manufacturing, operation, inspection, maintenance, regulation and crash investigation, igniting a safety revolution that ultimately transformed airline travel worldwide from the most dangerous form of travel to one of the safest/"

This including the banning of wooden construction for commercial aircraft (but not private) in the US.

Please note that a number of Sirius aircraft were later converted to Altairs. Serial numbers 143, 144. 145, 152 and 153. There may have been others?
No 153 started as a Sirius, became an Altair and was later used by the Army as YIC-25.

Transport aircraft would not be required to meet the same load standards as fighter aircraft.
Not all commercial/private aircraft had to meet the same load standard.

see Airworthiness certificate - Wikipedia

for a modern overview.

Prior to 1927 there was no or darn little government inspection in the US so it took a while for things to evolve.
 
Shortround6 said:
You are in an era when things may have been in a state of flux as far as government regulations were concerned.
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Wow, that's quite serious. I assume the US Army had more concerns about structural strength in aircraft designs correct?
 
I think you are confused about these 1930 era aircraft.

From Wikipedia
Lockheed Sirius. Two versions of the same basic design were built for the United States Air Force, one made largely of wood with a fixed landing gear, and one with a metal skin and retractable landing gear, designated Y1C-25 and Y1C-23, respectively. Its basic role was intended to be as a utility transport. A total of 15 Sirius aircraft were constructed in 1929 and 1930. The first and best known Sirius was bought by Lindbergh, and in 1931, as NR-211, it was retrofitted to be a float plane. Lindbergh and his wife Anne Morrow Lindbergh flew it to the Far East, where she wrote a book about their experiences there entitled North to the Orient.

Lockheed Altair was a single-engined sport aircraft of the 1930s. It was a development of the Lockheed Sirius with a retractable undercarriage, and was the first Lockheed aircraft and one of the first aircraft designs with a fully retractable undercarriage. The prototype Altair was purchased by the United States Army Air Corps and designated Y1C-25, with a second Altair, fitted with a metal construction fuselage was also purchased by the Army as the Y1C-23 and used as a staff transport, as was a single similar aircraft operated by the US Navy as the XRO-1.

Lockheed / Consolidated P-24/P-30 (PB-2, A-11) was a 1930s United States two-seat fighter aircraft. An attack version called the A-11 was also built, along with two Y1P-25 prototypes and YP-27, Y1P-28, and XP-33 proposals. When the Detroit Aircraft Corporation failed, who started the design and won the U.S. contract, the chief designer of the YP-24, Robert J. Woods was hired by Consolidated Aircraft. Woods continued to develop the YP-24, the design becoming the Consolidated Model 25, with all-metal wings replacing the wooden wings of the YP-24 and a larger tail. The Army Air Corps ordered two prototypes as the Y1P-25 in March 1932, to be powered by a Curtiss V-1570-27, fitted with a turbo-supercharger on the port side of the forward fuselage. The order for the second prototype was quickly changed to a Y1A-11 attack aircraft, omitting the supercharger.

Lockheed Altair (From My collection)

Lockheed Sirius (From Wikipedia)


Consolidated P-30/A-11 (From My collection)


Consolidated YP-24 (From My collection)


 
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The drawings you have posted are copyrighted materials done by Lloyd Jones and, as such, should be credited to both Lloyd and the publication from which they came. The source of each of the photos should also be indicated.

AlanG
 
The drawings were left with signatures on and photos were credited, ones from my collection I have prints of and many were made from negatives in photo labs where I was stationed in the Air Force or rescued from a dumpster in the Air Force, or purchased from auction sites. I did not know the names associated with the drawings. The drawings are from the net.
 
I would note that the Detroit Aircraft Corporation had a connection with Lockheed and built several of their designs in modified form.

From Wiki: "However, in 1929, the management of Lockheed voted to sell majority share ownership to the Detroit Aircraft Corporation. In July 1929, the Detroit Aircraft Corporation acquired 87 percent of the assets of Lockheed.Lockheed Aircraft Company"

The versions built in Detroit often had a metal fuselage with wooden wings compared to Lockheeds all wood construction.

Consolidated had built the "Fleetster

Which looks like a Lockheed Vega on steroids but might only be a case of imitation being the sincerest form of flattery.

You can draw all kinds of connections but the words "Developed from" might not be too far from "inspired by" which may mean few, if any common parts even if the same designer/engineer worked on both planes.
 
I know the USAAF had an obsession with twin-seat fighters to defend against lufbery circles, provide a flying gunship for protecting bombers, and essentially either be fighter bombers in one, or a high-altitude variant as a fighter, and a low altitude version as a fighter-bomber.

That being said, it is interesting to contemplate how much performance could have been gained in either maneuverability, speed, or range by removing the gunner. It would be beneficial from the standpoint of weight-reductions, streamlining, agility, top-speed, climb-rate, and with the same amount of fuel onboard, greater range. If the weight of the airplane was sufficiently light, you could also make the wing a little smaller and retain the same agility, and reduce drag. Even if the weight wasn't changed an ounce, the missing weight could be replaced with structural supports that would strengthen the plane, providing superior g-load capability, or extra fuel for range.
 
I am not sure the USAAC did have an obsession with twin-seat fighters to defend against lufbery circles.Lufbery circles are a defensive maneuver not an offensive one.
In any case they only built 26 two seat fighters from the end of WW I until they built the P-30, hardly an obsession.

It used same engine as the P-30 only without the turbo charger.

They also had pretty good idea what a single engine fighter would do.

Same Curtiss V-12 engine.
 
I really don't know what they were thinking, except that various schools of thought (tactics/doctrine?) were competing with each other and they may have been buying small quantities of aircraft to test out the theories.

remember that this was being test flown at the time they were taking deliveries of the P-16 biplane.

There was a Curtiss powered version

and yes, the landing gear did retract (semi)

SO the idea of the P-16 acting as a escort seems a little far fetched. (bombers are faster than the escorts)
By the time you get to the P-30s the AAF is buying B-10s
 
Shortround6 said:
I really don't know what they were thinking, except that various schools of thought (tactics/doctrine?) were competing with each other and they may have been buying small quantities of aircraft to test out the theories.
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I'm curious what the doctrines were to be honest
he idea of the P-16 acting as a escort seems a little far fetched. (bombers are faster than the escorts)
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Actually, the P-24 was faster than the B-10 (235 vs 205-215)
By the time you get to the P-30s the AAF is buying B-10s
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The P-30 could do 275
 
Bomber escort wouldn't be done at the bomber's top speed.
It's probably going to be close to it's cruising speed, and if it's a formation of bombers, it's going to be at the slowest bomber's cruising speed.
 
The PB-2A had a maximum speed of 274 mph at 25,000 feet, 255.5 mph at 15,000 feet, and 214 mph at sea level. It could climb to 15,000 feet in 7.78 min. Service ceiling was 28,000 feet and range was 508 miles.

B-10. Maximum speed 213 mph at 10,000 feet, 196 mph at sea level. Normal range 590 miles, maximum range 1240 miles, ferry range 1830 miles.

SInce the B-10 had engines that had a critical attitude of 5400ft and the PB-2A/P-30 had an engine with a critical altitude of at least 15,000ft one could guess that they were not going to operate at the same altitudes.

The Army was thinking years ahead and was ordering stuff to test it out for future plans. The P-30 was far from the first turbo equipped aircraft the army had ordered.
 
tyrodtom said:
Bomber escort wouldn't be done at the bomber's top speed. It's probably going to be close to it's cruising speed, and if it's a formation of bombers, it's going to be at the slowest bomber's cruising speed.
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Makes sense, however some people simply seemed to focus on top speed and not cruise.

The range wasn't all that much different, not sure what cruise speed was for either aircraft.
The Army was thinking years ahead and was ordering stuff to test it out for future plans. The P-30 was far from the first turbo equipped aircraft the army had ordered.
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Yeah, they had an obsession with turbochargers: On the bright side, we were the only nation that mass produced them.
 
In the early 30s 2 pitch and variable pitch propellers were just coming into use, The P-16 pictured used a fixed pitch prop. Cruising speeds were often 70-90% of full speed. Some engines did NOT have military ratings. The HP figure normally published was the max continuous power in many cases.

The US was ordering a variety of planes in small numbers. trying to figure out doctrine or planed tactics in case of a future war based on the purchase of a couple of dozen planes seems like a stretch.
The US Army was "obsessed" with turbos because the only supercharger manufacturer in the US was obsessed with them (any company using superchargers on their aircraft engines (and Curtiss normally did not) bought not only the designs but many of the parts from General electric. The turbo was also a way to altitude performance in an era with crappy gas. Turbo work on Army experimental planes started when gas was 73 or 80 octane and if the engine was not designed to use boost (engine driven supercharger) to begin with then a turbo set up to deliver sea level air pressure at higher altitudes is one way of trying to improve performance without breaking things.
 
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