ID for fun

[Randy Wilson]

I had promised to give some background on the ABC Dragonfly engine (posted above a ways) and I particularly like the description in "Plane Speaking; A personal view of aviation history" by Bill Gunston, noted aircraft engine historian and author. His Chapter 8, "January 1918 - Cancel the Others …" is only two pages long but certainly tells the story well. Here is a summary in my words, with quotes from the chapter.

The chief designer of ABC Motors had designed a 7-cylinder radial engine, the ABC Wasp, of 170-200 horsepower whose dry weight was only 290 pounds. The Dragonfly was to be an upsized 9-cylinder radial engine of 340 horsepower, with a weight of 600 pounds. In January 1918, the British Air Board decided to make the Dragonfly the "virtually standard engine for all future fighters and bombers." Orders were placed with 13 companies to produce 9,700 engines. One design, the Nieuport Nighthawk, was going to be the new standard fighter, powered by a Dragonfly engine.

Unfortunately, the Dragonfly turned out heavier, 656 pounds, and with less power, only 295 horsepower at its rated 1650 rpm. But that wasn't all, as the engine overheated badly, and after a few hours in the air, it basically shook itself apart! The short answer was that the engine was designed, without realizing it, to "run at the critical torsional-vibration frequency of the crankshaft." After over 1,300 of the engines had been produced, it was realized that the whole design would have to be redesigned completely. Mr. Gunston ends his chapter with "The one good result was it spurred Major B.C. Carter at Farnborough to undertake valuable research into torsional vibration."

As a side note, the Air Board had earlier ordered another engine, the Sunbeam Arab V-8 of 200 horsepower, which "proved to suffer from a weak crankcase, faulty cylinder attachment, and severe vibration, which took many months to cure." At this time, several hundred SE.5a fighters were "waiting for engines" and "British engine supplies were in a state of crisis." If the war had continued past November 1918, the British would have been almost without reliable, modern aircraft engines.

Hopefully, Dan K's response above will make more sense to those without prior knowledge of the ABC Dragonfly engine. By the way, Bill Gunston's "Plane Speaking" is a great read for any aviation buff. Since we seem to be stuck home for a bit longer, heck I may just reread it myself

Randy

[bdk]

Wow, the shape of the Napier-Heston racer is so Art Deco. Gorgeous! Wouldn't it be cool to have a class of aircraft from this era running around the pylons at Reno?

Art Deco indeed...Me209, Curtiss XP-37, Stanzel Tiger Shark, Gee Bee Z, and many pulp comic airplane designs of the day. Incidentally the Napier Heston Racer was a fine wrapping, tho tragic, debut of the lovely Napier Sabre.

I can see the Heston flying cover for this:


http://impdb.org/index.php?title=Things_to_Come

[Pogo]

Trying to see if anyone enjoys these kind of posts

Randy, I think it's a cinch 'these kinds of posts' are welcome indeed. At least, it's what I think, and I vote you keep 'em coming.

[bdk]

"No illustration of the Napier Sabre engine may be published, but these are the bearers for it."

No longer a secret I guess, yet good info is still hard to find on the Sabre!

Wow, the shape of the Napier-Heston racer is so Art Deco. Gorgeous! Wouldn't it be cool to have a class of aircraft from this era running around the pylons at Reno?

Incidentally the Napier Heston Racer was a fine wrapping, tho tragic, debut of the lovely Napier Sabre.

[Randy Wilson]

This link is to a page at the NASM with eight views of a Napier Sabre IIA engine.

https://airandspace.si.edu/collection-objects/napier-sabre-iia-horizontally-opposed-24-engine/nasm_A19670111000

Randy

P.S. for bdk: Two sources for more on the Sabre are "Allied Aircraft Engines of World War II" by Graham White with about eleven pages on the engine and its primary aircraft, and the second is "British Piston Aero-Engines and their Aircraft" by Alec Lumsden which has about four pages on it. Both have info on earlier Napier engines. Just FYI. Randy

P.P.S. - forgot one, "Major Piston Aero Engines of World War II" by Victor Bingham, has a whole Chapter 9 on the Sabre and its aircraft of nine pages. It has an interesting discussion of the issue of manufacturing sleeve valves for the engine, also touched on in the two above.

[airnutz]

"No illustration of the Napier Sabre engine may be published, but these are the bearers for it."

No longer a secret I guess, yet good info is still hard to find on the Sabre!

Wow, the shape of the Napier-Heston racer is so Art Deco. Gorgeous! Wouldn't it be cool to have a class of aircraft from this era running around the pylons at Reno?

Incidentally the Napier Heston Racer was a fine wrapping, tho tragic, debut of the lovely Napier Sabre.

Back when I had TCM, they'd show Things To Come from time to time whereupon we would pay homage and assume the position...

Brandon, there's a link to a nice colorized Max Millar cutaway drawing of the Sabre at the bottom of the Napier Sabre Wiki page in the external links section.

Here's some nice animations illustrating the choreography of the internals of the Sabre posted on the excellent Hawker Tempest website...
http://www.hawkertempest.se/index.php/c ... o-pasquali

...And lastly, here's a link to a site with restored blueprint copies of the Sabre for sale, but if you scroll down past that there is some excellent quick paragraphs explaining the internals for recent initiates. Further down yet in the green box is more history giving some development and service issues with some solutions...
http://www.aviationshoppe.com/sabre-ii- ... p-256.html

The http://www.hawkertempest.se site has more thorough info and even some Sabre sound clips...
James

[Randy Wilson]

If you don't mind a First War type. Maybe a bit tricky. More info later. Randy

Attachments

[Baldeagle]

Gotha G.I



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[Randy Wilson]

Close but not technically correct. I mentioned this could be a bit tricky. Randy

[Dan K]

Close but not technically correct. I mentioned this could be a bit tricky. Randy

Pre-Gotha... Friedel-Ursinus Kampfflugzeug

[Randy Wilson]

Dan K - yes, specifically the Friedel-Ursinus B.1092/14, photo taken on 20 February 1915. This was the design turned over to Gotha in March 1915 to become the Gotha G.1. It is late, so a bit more on it in the morning. Good work to you and Baldeagle on a fairly rare type. Randy

[Dan K]

Dan K - yes, specifically the Friedel-Ursinus B.1092/14, photo taken on 20 February 1915. This was the design turned over to Gotha in March 1915 to become the Gotha G.1. It is late, so a bit more on it in the morning. Good work to you and Baldeagle on a fairly rare type. Randy

Any explanation as to why the fuselage markings are “B.1089”? Was paint being rationed? Perhaps the extra weight would prevent flight?

[LysanderUK]

Adding a bit of back story to the Napier Sabre in the NASM collection, it's been stated elsewhere that this engine is probably from Typhoon 1b MN235, the sole surviving example that's now on display at the RAF Museum. MN235 was sent straight from the factory to the US for evaluation, although it appears to have done relatively little flying. The aircraft was traded back across the pond in the 60's minus engine.

Last edited by LysanderUK on Wed Apr 22, 2020 10:58 am, edited 1 time in total.

[Baldeagle]

Any explanation as to why the fuselage markings are “B.1089”? Was paint being rationed? Perhaps the extra weight would prevent flight?

It's a "92", just an odd Germanic font.

[bdk]

Here's some nice animations illustrating the choreography of the internals of the Sabre posted on the excellent Hawker Tempest website...
http://www.hawkertempest.se/index.php/c ... o-pasquali

I've not seen that animation before, it is fantastic!