Nerd's Corner - Ice cool aircraft recognition game.

[Bob]

I think it is a confusion between Torque production, which is wholly achieved by the actions of gas pressure on the engines pistons, (nothing to do with the engines rotating mass, that can only store and release energy as in a flywheel) and the torque effect visualised by the Snipe start up, which to a great degree is a result of the ratio of masses of the rotating and non rotating parts of the whole assembly (aircraft mass: rotating mass of engine)

that was my oiginal point...is it incorrect?

In other words when the engine starts it is rather more inclined to to rotate the relatively low mass of the airframe than the relatively large mass of the engines rotating parts...it's not that the le Rhone is a massively torquey engine, it's just the effects of relative mass

last edit added the word massively....the le rhone is torquey, but not as much as torque reaction shown would imply


...Just call me Mr long-winded

P.P.S. I have de Man Flu, so any criticism of my mental perambulations will be directed to the effects of my self medication....so there

[Cacophonix]

I fear someone is extending the meaning of torque, as far as I know (and there is a lot I do not know) torque can be calculated from RPM and power and nothing else.

By definition (in physics/mechanics) torque is defined as a force that tends to cause rotation. Mathematically it can be associated with RPM and power but to say what you have said above is not entirely correct!

Caco

[Cacophonix]

I think it is a confusion between Torque production, which is wholly achieved by the actions of gas pressure on the engines pistons, (nothing to do with the engines rotating mass, that can only store and release energy as in a flywheel) and the torque effect visualised by the Snipe start up, which to a great degree is a result of the ratio of masses of the rotating and non rotating parts of the whole assembly (aircraft mass: rotating mass of engine)

that was my oiginal point...is it incorrect?

In other words when the engine starts it is rather more inclined to to rotate the relatively low mass of the airframe than the relatively large mass of the engines rotating parts...it's not that the le Rhone is a torquey engine, it's just the effects of relative mass

Your emboldened comment (see above) is absolutely correct, think of Newton's third law here about the resultant forces! Also keep in mind that in a rotary it is the rotation of the engine and the mass couple that produces the resultant forces (equal and opposite) and thus the effect on the rolling of the airframe by that force (remembering the F = M * A) is material. As for the comment about torquey engines well this is not precise but I understand (I think) what you mean and would go further and say that the effect of the relative displacement of the mass, and the centre of rotation, between the engine and the airframe that enhances the torque rolling effect in some aircraft (like the Snipe with a rotary engine in this case).

Caco

[Cacophonix]

Anyway, I have led the thread away from aircraft identification. Perhaps we should set up a physics thread here? Back to Cpt_Pugwash's aircraft.

Caco

[Bob]

Aaah, yes sorry, it's a Bell YFM-1 Airacuda

[Cpt_Pugwash]

Bob has it.

YHC.

[Bob]

Righto

Baddiet.jpg (106.85 KiB) Viewed 395 times

[Cacophonix]

Righto

Baddiet.jpg

Clearly American with that belly gun or ball turret on the underside and just the way the bloody thing looks, but do I know what it is? No is the answer!

Caco

[John Hill]

Google did not take long to find that one!

[Boac]

Is No 1 feathered in that picture? Rudder deflection certainly says yes.

[Cacophonix]

Google did not take long to find that one!

Well spill the beans then as nobody else seems to know! We won't tell anybody you cheated!

Caco

[Cacophonix]

Is No 1 feathered in that picture? Rudder deflection certainly says yes.

Well spotted! As you say the port prop looks like it is feathered.

Caco

[Bob]

A small hint........ IMO it looks about 5-6 years ahead of it's time

[Cacophonix]

A small hint........ IMO it looks about 5-6 years ahead of it's time

A pre world war US bomber then? Let me consult my big boy's book of US bombers then!

Caco

[Cacophonix]

I see that John Hill, with the fortitude and virtue of a Whakahoro sheep shearer, has stayed shtum about the aircraft's identity, despite having being punishment dipped multiple times. All that woolly virtue aside and nothing said by John, I can now announce that after wasting at least 40 minutes of my remaining lifespan fruitlessly searching for the aircraft in my big boy's book of bombers, I stumbled upon the aircraft on a website I have used previously to find rare birds to try and bamboozle myself and the folks here.

Bob's aircraft is to be found here and is a Stearman XA21... A Stearman for goodness sake!

The U.S. Army's road to the classic twin-engined attack aircraft of World War 2 (1939-1945) was a long one and saw many promising (and forgettable) types dropped from contention. This included the overlooked Stearman "XA-21" of which only one was built and failed to impress. The type first flew in 1938 but never materialized beyond its prototype status even after drastic changes had been implemented that included a redesigned nose. The product did, however, provide U.S. Army authorities exposure to twin-engined types (and their inherent strengths and weaknesses) that eventually led the adoption of platforms like the Douglas A-20 "Havoc" and North American B-25 "Mitchell" forms.

The XA-21 began life as the Stearman "Model X-100" and was developed to a standing USAAC ground attacker requirement. The Model X-100 was proposed with its unique nose section that showcased a long "greenhouse-style" canopy over the crew area. A twin-engine configuration was used to power the type (and was required by the USAAC for its new attacker). Three crew operated her various onboard systems and a conventional, single-finned tail unit was used. The wing mainplanes were high-mounted and each carried an engine nacelle. The engine of choice became 2 x Pratt & Whitney R-2180-7 "Twin Hornet" radials outputting at 1,400 horsepower.

Proposed armament included a single Browning 0.30 caliber machine gun in the nose and four additional guns fitted to the wings (two each). Four additional Brownings (0.30 cal) were then installed to face aft and tackle any approaching interceptor. Up to 2,700lb of conventional drop ordnance would be carried to fulfill the bombing requirement.

After the Army acquired the X-100 it was redesignated XA-21 for its test phase. It was quickly found to hold an inherent design flaw - namely its long greenhouse canopy that restricted the pilot's forward vision - this meant poor ground running, take-off, and landing qualities. As such, engineers were forced to completely redesign the nose section and it was then reborn as a "stepped" cockpit approach somewhat reminiscent of the Consolidated B-24 "Liberator" heavy bomber (detailed elsewhere on this site). The XA-21 continued in testing but did not reveal any stunning revelations about her to recommend her for serial production.

https://www.militaryfactory.com/aircraf ... ft_id=1535

Bob, you are a total bastard!

What a good and very interesting challenge!

Caco

[Cacophonix]

What is this? Easy one.

JohnBonhamMobyDick.JPG (61.61 KiB) Viewed 309 times

Caco

[om15]

German uniforms, and the engine layout is similar to a Gotha heavy bomber, but no variant of the Gotha has that cockpit arrangement.

Zeppelin-Staaken R.III,

[Cacophonix]

Quite correct om15. The marker is with you.

Caco

[Bob]

Bob, you are a total bastard!

You're not the first to notice, but thanks all the same matey

[Cukup Sudah]

Here's one to ponder while we wait for om15.