Now THAT'S a Spinner!

[rwanttaja]

Check out the spinner on the Morane Saulnier N. Can you imagine trying to make such a large symmetrical bowl in your shop? Yet the technology of 1915 wasn't that much above what homebuilders have now.

http://www.wanttaja.com/morane.jpg

The picture's so clear you can see the rows of fasteners holding the bowl to bulkheads fore and and aft of the propeller.

I'm curious as to the material used. Aluminum was pretty high-tech in 1915, and sheet steel would have to have been pretty thin to keep the weight down. Could this possibly have been turned wood?!!!!

Also, look at the deflector plates installed on the faces of the propeller to deflect the bullets from the Lewis gun....

Ron Wanttaja

[cwilliamrose]

Was metal spinning common back then? Seems like the cowlings on some WWI airplanes were spun.

[Floatsflyer]

According to Wikipedia:

The Morane Saulnier Type N Bullit had a "large metal casserolle spinner designed to streamline the aircraft but caused the engine to overheat. In 1915 the spinners were removed and the overheating problems disappeared with little loss in performance."

[BusyLittleShop]

Yes I can imagine Ron... to make a spinner then and as well as now you start with a flat piece of aluminum and work it by hand onto to a buck in a Lathe...


https://youtu.be/yrTDBW6q7Xg

[rwanttaja]

Yes I can imagine Ron... to make a spinner then and as well as now you start with a flat piece of aluminum and work it by hand onto to a buck in a Lathe...
Absolutely outstanding...Thanks!

Ron Wanttaja

[BusyLittleShop]

You're welcome Ron...

The Morane Saulnier was inspired by the success of Louis Bechereau's
1912 Deperdussin monoplane racer... powered by a 190HP Gnome Lambda
14-cylinder twin-row air-cooled rotary it was the worlds first
aircraft to exceed 100 MPH barrier... just think in 1912 the worlds
knowledge to engineer high speed aircraft was only 5 years old thanks
to the Wright Brothers going public in 1907... Look closely and you
can see the design trends that will follow in the years leading up to
WW2... namely enclosed aerodynamic cowl and spinner to not only lower
the drag of a radial engine but to manage the air for greater cooling...

1912 Deperdussin was not only fast but also the first pure sex with
wings aircraft...

http://2.bp.blogspot.com/_FEcHJfaMW1o/Sa6W1Nt9msI/AAAAAAAAHOc/GgWhleD_4Do/s400/Deperdussin5.jpg
http://www.ctie.monash.edu.au/hargrave/images/dep_gb_provost_041013_500.jpg

The iconic Deperdussin is also popular with replica builders...

https://alchetron.com/cdn/deperdussin-monocoque-2276510e-d5e5-415e-ad21-7ab2f4bdb30-resize-750.jpeg

[BusyLittleShop]

According to Wikipedia:

The Morane Saulnier Type N Bullit had a "large metal casserolle spinner designed to streamline the aircraft but caused the engine to overheat. In 1915 the spinners were removed and the overheating problems disappeared with little loss in performance."

I doubt the claim because the advantage of the rotary engine's success
was improved cooling: when the engine was running, the rotating
crankcase cylinder assembly created its own fast-moving cooling
airflow, even with the aircraft at rest or sporting a spinner...


https://youtu.be/atMn9s6m-j4

[Dana]

I doubt the claim because the advantage of the rotary engine's success
was improved cooling: when the engine was running, the rotating
crankcase cylinder assembly created its own fast-moving cooling
airflow, even with the aircraft at rest or sporting a spinner...


Spinning the engine helps, but you still need to have cool air coming in. If the engine is spinning inside a box of hot air, the air will be circulating but it won't do much cooling.

[Frank Giger]

Aluminum was crazy expensive back then, but we must remember that these aircraft were on par with professional racing cars today - the elite air racers of their day, where dollars-for-speed was just a given.

If the spinner alone costs as much as a wing but gives one an extra three miles an hour in reduced drag, so be it. The spinner goes on. There are trophies and records on the line, and who can put a dollar value on that (well, except for the people putting up the prize money)?

[rwanttaja]

My thought is that the spinner was eliminated due to maintenance issues. It'd be crazy hassle to remove the thing to get at the front of the engine, especially when there's a huge bulkhead on the front of the prop to support the spinner.

Ron Wanttaja

[BusyLittleShop]

Spinning the engine helps, but you still need to have cool air coming in. If the engine is spinning inside a box of hot air, the air will be circulating but it won't do much cooling.

True Dana... if the engine were confined inside a box a rotary would
be spinning in its own heat of combustion and exhaust but that is not
what we see on the Morane Saulnier... the designers engineered a gap
between the spinner and cowl to allow a path for cooling air to enter
and at bottom there is no cowl what so ever which is another design
feature to allow the cylinder to exhaust in the exposed air stream...
technically speaking I don't see a possible problem of over heating
rather I see a number of novel measures taken by the engineers to
sufficiently manage precious cooling air...

8086

[BusyLittleShop]

My thought is that the spinner was eliminated due to maintenance issues. It'd be crazy hassle to remove the thing to get at the front of the engine, especially when there's a huge bulkhead on the front of the prop to support the spinner.

Ron Wanttaja

In the time of war leave it up maintenance to find a short cut to a crazy hassle... like install quick fasteners to cowling to get at the engine...

(Its worth noting the chief reason rotarys sported cowls was to divert the Castrol oil spray away from the pilot and onto the bottom of the aircraft)

[Mayhemxpc]

My thought is that the spinner was eliminated due to maintenance issues. It'd be crazy hassle to remove the thing to get at the front of the engine, especially when there's a huge bulkhead on the front of the prop to support the spinner.

Ron Wanttaja

Ron, I think you are probably on target there. When people ask why my plane (O-2A) doesn't have spinners while the civilian 337 (and O-2B) do, I say that when operating in remote locations, on Laterite or PSP runways, spinners just lead to cracked spinner bulkheads and more maintenance. (I am not 100% sure this is true, but former USAF maintenance personnel who worked on the planes agreed with me.)

-- Chris

[Airmutt]

I doubt that the spinner and those deflectors bolted on the back were channeling much cooling air thru that narrow opening. The Morane appears to have been pretty tightly cowled. Don’t think the video of a uncowled rotary engine turning a modern design prop validates any claim about rotary engine cooling.
When Lockheed changed the engine/prop combination for the C-130J it suffered many cooling and ventilation issues. Took a redesign of the oil cooler pan and augmentation system, a change of the beta schedule and interior nacelle ventilation changes to name a few.
There are other examples over where airflow or lack of has adversely effected the performance of turbo chargers, oil coolers etc. and forced design changes.
But I agree with Ron, the maintainers were probably glad when the spinner was officially removed.

[BusyLittleShop]

Here is custom spinner to behold with a tight air gap... 3350 powered RareBear... no cooling problems noted...

8102

[Airmutt]

Oh wow, 3 bladed prop and the white & gold paint scheme - that’s a throw back pic. Didn’t mean to imply that it can’t be done. My comment was to the most likely poor efficiency of the Morane’s prop with the deflectors attached.
Rare Bear is any interesting combination parts and a lot of engineering. Quite the plane for what was essentially started from pile of parts.

[BusyLittleShop]

In 2002 Rare Bear sported a three blade propeller off Lockheed P3 Orion attached to Lockheed Constellation hub but
after back-to-back testing in 2004, a switch was made back to the Aeroproducts four-bladed propeller...

Historically speaking those defectors were history after Garro's Morane was captured and Fokker designed the synchronized firing mechanizum...

8103

[Airmutt]

The blades maybe have been from a P-3 but Lockheed never used a 3 blade setup on the Orion. Early C-130s had a 3 blade configuration which was a Curtiss Electric setup. The Ham Std blades were essentially the same except for the tip shape. The square Herc prop was referred to as the power blade while the rounded Orion tip was referred to as the speed blade.

[Dana]

The blades maybe have been from a P-3 but Lockheed never used a 3 blade setup on the Orion...

Maybe that's why they used Constellation hubs...

[Ron Blum]

Fascinating thread!!!

My guess is that Airmutt (Dave) is correct. BIG spinners are good (streamlines the rest of the airplane). I would guess that the propeller was stopping most of the cooling flow. When the spinner was removed, more frontal area was exposed to get a little more cooling area. Even though it's a huge spinner, it is not very long. The flow (streamlines) probably didn't change a lot with or without the spinner.

Bottom line: Tradeoff between cooling flow and strength of the root section. Solution: Bigger spinner to allow a longer/larger root section and a better blade/blade angle out a little further.

Way cool thread!!!

[BusyLittleShop]

A closer look at those bullet defector plates from the Epic of Flight...

In 1915 from an airfield near Dunkirk, French Lieutenant Roland Garros
took off armed with defector plates that for a time would make his
Morane Saulnier the most feared weapon in the air. Before the War
Garros had won acclaim at international air meets, had set an altitude
record of more than 18,000 feet and-in 1913- had become the first man
to fly across the Mediterranean. But his first efforts as a combat
pilot had netted him nothing. "I was able to outmaneuver my
adversary," Garros wrote, "but my observer never succeeded in shooting
him down with the light rifle, carbine or shotgun that constituted our
armament."

On a visit to Paris, Garros expressed his frustration to Raymond
Saulnier, the plane builder. In April of 1914 Saulnier had applied for
a patent on a cam-operated mechanism that, in theory at least, would
enable a machine gun to fire cleanly between the blades of a revolving
propeller. The design was sound enough. Unfortunately, the available
Hotchkiss machine gun tended to fire at an uneven rate and the
ammunition it used produced a high proportion of delayed " hang-fire"
rounds. No device could keep it from mistiming and shooting up the
wooden propeller. But Saulnier also showed Garros something else he
had designed: a steel deflector that, when fastened to the propeller,
would protect it from damage by the small percentage of bullets that
might actually hit it. Intrigued, Garros and another friend, master
mechanic Jules Hue, set to work to test the deflector idea. They
bolted a gun and engine onto an obsolete plane. I started the
engine, wrote Hue. "Garros fired and everything collapsed. The
engine fell to the ground, one blade of the airscrew having flown off,
and the fuselage broke behind the cockpit. What had happened? One of
the braces holding the deflectors had broken.

Hue thereupon fashioned better braces and produced a more streamlined
set of deflectors: wedge shaped, with gutter-like channels for the
bullets. In March Garros reappeared at St. Pol airdrome near Dunkirk
with a Hotchkiss gun on a fixed mount behind the shielded propeller of
a Morane-Saulnier monoplane, and on April 1 he took off alone toward
the German lines.

Officially, his mission was to bomb the railroad station at nearby
Ostend. But along came a German Albatros, seeking a look at the Allied
trenches after a week of bad weather. Garros, climbing, bore in on the
German plane. Then, from just behind his propeller came the orange
winking, the thin smoke trail, the noisy rattle of a machine gun. The
surprised Germans fired back with a carbine, but it was no contest.
Garros furiously slammed fresh ammunition into the gun until, on the
third clip, "an immense flame burst out of the German motor and
spread instantly." The Albatros went into a wide spiral and crashed. "I
gazed below me for a long time," Garros wrote later, "to convince
myself that it was not a nightmare.

Never before had a man aimed his entire plane as though it were the
weapon, and shot through the propeller to bring down an enemy. The
deflectors might be jury-rigged and imperfect, but they had worked,
and the prophecy for the future was incalculable. On April 15 Garros,
again firing through the shielded propeller, shot down a second German
plane. Early in the morning of April 18 he got his third, making him
second only to Pegoud, with five.

But later that very day Garros trumped himself. In the afternoon he
again took off from Dunkirk, swooped too low behind the enemy lines
and had his gas line cut by a single bullet fired from the ground.
After gliding to earth, he tried to set fire to his plane to protect
the secret of its armament. But he was too slow. German troops
captured the plane, and Garros, intact.

The Germans were jubilant over the opportunity to unravel the mystery
of the French plane that had destroyed three of theirs in less than
three weeks. Ironically, the technology needed to develop an even more
sophisticated method of shooting through the propeller was already
available to them. Franz Schneider, a Swiss engineer working in
Berlin, had applied for a patent on a synchronizing device even before
Saulnier had; unlike the French, the Germans had an air-cooled
Parabellum machine gun that was reliable enough to be adapted to the
timing mechanism. But Schneider had been given no machine guns to work
with. Instead, once Garros and his plane were in their hands, German
authorities assigned another engineer to develop an imitation of the
captured French device. Meanwhile, Allied airmen continued to dominate
the sky.

Enter Fokker and his team and they built a cam-operated push-rod
control mechanism connecting it to the oil-pump drive of an Oberursel
engine and the trigger of a Parabellum machine gun. They then attached
a plywood disc to the Oberursel's propeller and kept test-firing until
they got an even pattern of bullet holes between the blades. Finally
they mounted the whole works on the Fokker M.SK and reported to
Doberitz air base with the world's first reliable single-seated
fighter plane. The operation had taken, not 48 hours, but several days
of around-the-clock work.

From defecting bullets to synchronized forward firing to a mono plane
sporting enclosed aerodynamic cowl and bullet spinner, all the
beginnings of a modern fighter...

Roland Garros...
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