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Stiletto-
11-07-2007, 04:35 PM
Hello, I recently was thinking about this. In WWI they started off mostly with Monoplanes like the Moraine Bullet and the Fokker Eindecker, but as the war progressed and throughout it and after the Great War, Biplanes were at the fore front (and rightly so, all the best planes of the war had 2 wings). The maybe one exception of a good late war design being the Fokker D.VIII, it had an underpowered engine with only 110hp but do to its parasol-monoplane design, it had low dragna d light weight and could do 126mph (204kmh).

On the other end of the spectrum we have triplanes like the Sopwith and Fokker Dr.I which was a copy of a Sopwith that had been captured. The Dr.I as well only had 110hp and only did 115mph (180kmh) but do to the lift from it's 3 wings, it had a great climb rate and in a turn was highly maneuverable. It's apparent that all 3 types of planes could be successful in World War I.
Fastforward to World War II.. As the war started there were many Biplanes in service, as the war ended they were by far obsolete, probably obsolete by 1940 or 41 at the latest as the shift went into modern monoplane designs.

My question is, at what point do you go from a Monoplane to a Biplane? I am thinking as engines developed over the years and produced more power and the planes got faster (obviously generating more lift) the need for a second wing was not as necessary. I also think this goes hand and hand with fighter tactics, as dogfighting became less encouraged and the boom and zoom method was.
A "modern" monoplane had enough power to fight in the vertical where as an underpowered plane would be much easier to stall and thus it was better at fighting in the horizontal and thus the use of 2 wings instead of one. But where is the grey area where you start needing a monoplane more and a biplane less? 700? 800hp? 900hp? Also the aerodynamics must play a part as well.

If you look at the I-153 and I-16, they both were generally made at the same time with the same power plant, and are relativley similar besides their differences in their wings. The I-153 does about 265mph (426kmh) Where the I-16 (Type 18) can do 288mph (464kmh). The trade off seems similar to those found in world war one, even with 9 times the horsepower, while the I-16 is a bit faster, the I-153 can climb slightly better and is better in a turn. It is hard to say which is the inferior plane (as both were pretty inferior to what the germans were using http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif) I think it pretty much comes down to pilot choice between these 2 aircraft.

With my point being, when is it better to buld a Monoplane than a Biplane? it is evident that speed was king by the end of WWII and one of the main reasons of having a Monoplane was for speed and these designs being able to fight through the vertical, retaining energy unlike the old biplanes of WWI which pretty much had to use the horizontal. If the trend was to "boom 'n zoom" in WWI instead of getting into large furballs, do you think that possibly Monoplanes would have been more prevalent (and ultimatley more succesfull than biplanes) if the tactics dictated the hit and run? Maybe it doesn't have to do so much with an engines hp and the aero efficiency of a plane?

Your additional thoughts are welcome.

BlitzPig_DDT
11-07-2007, 04:53 PM
Strength.

Early mono-planes were all flex wings. The trouble is, flex wings can only carry so much weight, turn so hard, and go so fast. So they needed ailerons ("little wing" - developed by Curtiss (IIRC) to beat the Wright patent on aicraft control), however, now you had a problem of being able to break the plane much more easily from the increased control.

So bi-planes developed. Sure, more lift, but far more drag. The point was that you boxed the wings, adding more strength than weight, and none of it dead weight as it helps lift as well. Now you can go faster, roll quicker, turn harder, and carry more weight.

The Fokker Dr.1 was revolutionary because it used unbraced (cantilever) wings. They were strong enough to not need wire bracing, which made the plane a bit tougher in combat too. But that's why Fokker was able to make the D.VIII. Cut the middle 2 wings out (since there is a mini-aerofoil in the undercarriage), and now you reduce drag significantly (although, depending on prop, some Dr.1s could go 115mph - it was much closer to (in terms of speed), and a much better turner, than the vaunted Sopwith Camel - outclimbed the Camel too).

Junkers had an all metal, low wing mono-plane at the end of the war, it just never saw service.

So that's why - reduce drag, and go faster. And when - when you can make the wing strong enough without having to brace it with another.

Pirschjaeger
11-07-2007, 10:24 PM
When is it better to build a monoplane rather than a biplane? I'd say just before the other guy does,....technology permitting.

Both planes have their advantages depending on the situation but in the end it's the BnZ'er that has the better chances.

Fritz

Stiletto-
11-08-2007, 04:01 PM
Okay DDT, so you think that if there wasn't an issue of structural integrity that most planes would have been Monoplanes during WWI? I can see this to some extent, though I think lift was more important than drag in these days since you aren't going much faster than 100 miles per hour, where as drag is much more significant at 400 miles per hour.

M_Gunz
11-08-2007, 05:17 PM
Originally posted by Stiletto-:
Hello, I recently was thinking about this. In WWI they started off mostly with Monoplanes like the Moraine Bullet and the Fokker Eindecker,

Have you been doing your learning from The History Channel? They started off with both types.
Until the Eindekkers, the major action was by 2 seaters and all of those I know of are biplanes.
Bombers, recon planes and gun busses -- all 2 seaters. 1914-1915 you might have found Bleriots
used in some ways, as spotters up until things got really competitive.


but as the war progressed and throughout it and after the Great War, Biplanes were at the fore front (and rightly so, all the best planes of the war had 2 wings).

Huh? DrI was definitely one of the best, DVIII would have been.


The maybe one exception of a good late war design being the Fokker D.VIII, it had an underpowered engine with only 110hp but do to its parasol-monoplane design, it had low dragna d light weight and could do 126mph (204kmh).

That was very fast for those days.


On the other end of the spectrum we have triplanes like the Sopwith and Fokker Dr.I which was a copy of a Sopwith that had been captured.

Glurk? Copy??? Copy ended with using 3 wings. Fokker used short wide wings that allowed the
DrI to yaw very quickly. It could be flat turned at insane rates as Vernor Voss demonstrated.
Same with the length, it was made short to reduce swing weight in yaw turns.

It had the new thick Gottingen wings with foil close to what later became the standard, the
Clark Y wing. Sopwith had thin wing foils; much more stall prone and poor lift compared.
Sopwith had external wire bracing, DrI had never done before internal bracing with stronger
wing spars only allowed by the new thick wings.

DrI was as different from Sop Tripe as 109 from I-16.


The Dr.I as well only had 110hp and only did 115mph (180kmh) but do to the lift from it's 3 wings, it had a great climb rate and in a turn was highly maneuverable. It's apparent that all 3 types of planes could be successful in World War I.

Could be? http://forums.ubi.com/images/smilies/blink.gif


Fastforward to World War II.. As the war started there were many Biplanes in service, as the war ended they were by far obsolete, probably obsolete by 1940 or 41 at the latest as the shift went into modern monoplane designs.

They were obsolete in 1938 and total jokes in 1941.


My question is, at what point do you go from a Monoplane to a Biplane? I am thinking as engines developed over the years and produced more power and the planes got faster (obviously generating more lift) the need for a second wing was not as necessary. I also think this goes hand and hand with fighter tactics, as dogfighting became less encouraged and the boom and zoom method was.
A "modern" monoplane had enough power to fight in the vertical where as an underpowered plane would be much easier to stall and thus it was better at fighting in the horizontal and thus the use of 2 wings instead of one. But where is the grey area where you start needing a monoplane more and a biplane less? 700? 800hp? 900hp? Also the aerodynamics must play a part as well.

The time to change was when wings got thick enough for internal bracing.

But what sells is what worked before and military budgets suffered during the post-WWI years
DUE TO massive near-worldwide economic trauma (US caught it late, but caught it hard) following
the worldwide flu epidemic (no common aspirin, no alka-seltzer, no flu shots) that killed over
20 MILLION people not to mention much farmland deeply polluted and 'mined' with unexploded
shells killing farmers that were left. Nickel and dime budgets do not push upgrades along.


If you look at the I-153 and I-16, they both were generally made at the same time with the same power plant, and are relativley similar besides their differences in their wings. The I-153 does about 265mph (426kmh) Where the I-16 (Type 18) can do 288mph (464kmh). The trade off seems similar to those found in world war one, even with 9 times the horsepower, while the I-16 is a bit faster, the I-153 can climb slightly better and is better in a turn. It is hard to say which is the inferior plane (as both were pretty inferior to what the germans were using http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif) I think it pretty much comes down to pilot choice between these 2 aircraft.

With my point being, when is it better to buld a Monoplane than a Biplane? it is evident that speed was king by the end of WWII and one of the main reasons of having a Monoplane was for speed and these designs being able to fight through the vertical, retaining energy unlike the old biplanes of WWI which pretty much had to use the horizontal.

You should try playing a WWI sim for a while.
Howard Hughes made Hell's Angels in 1930 and used actual WWI planes he brought back at the end
of the war. They use plenty of vertical during the fight scenes directed by HH who was there
in the air in WWI and aimed for technical accuracy in all the aerial scenes, even flew himself.
A wonderful film if you want to see the real things in realistic action.


If the trend was to "boom 'n zoom" in WWI instead of getting into large furballs, do you think that possibly Monoplanes would have been more prevalent (and ultimatley more succesfull than biplanes) if the tactics dictated the hit and run? Maybe it doesn't have to do so much with an engines hp and the aero efficiency of a plane?

Your additional thoughts are welcome.

Go monoplane.

A lot of speed limits prior to WWII were DUE TO fixed props that are only good to so fast and
not really efficient at any speed.

There's a whole lot more to the design choices than quickly meets the eye or gets on the average
made for 8th graders "educational" shows.

In early WWI, one 2 seater would get over the other, match speed and then drop a brick.

ElAurens
11-08-2007, 06:56 PM
The single biggest reason for the dominance of biplanes in the early years of aviation is lack of engine power.

Most early aircraft could barely drag themselves into the air. Aero engine development was in it's infancy. Engines were heavy and produced very low specific outputs. The only way to maintain any kind of safety margin with the paucity of thrust available in the early days was to drastically increase lift. How do we increase lift?

More wing.

BlitzPig_DDT
11-08-2007, 08:22 PM
It's sorta both El. To support a single wing with ailerons and the associated complexity would make things too heavy without adding lift. Rather than add dead weight, why not make it pull it's weight (so to speak)?

Even a 110hp Oberusal could power a monoplane to some of the best performance of the war (and the LAST kill of it). http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Stilleto - Look at the Etrich Taube. Possibly the first bomber, and one of the fist war planes too. Not only beautiful to look at, and slow, and weakly powered, it was a mono-plane wing warper, that while fragile, could lift 2 people, plus some extra gear and even light bombs. Don't need 2 wings to do that. But it's also not going to go fast or roll hard - it would collaps like piece of newspaper.

Also, think they weren't going fast? The Pfalz D.XII, Albatri, SPAD, and even SE5a were about speed. More so the first 3. They could turn, but relative to what? The Dr.1 was ignored. It's fame comes from Richtofen (even though it SHOULD come from Voss, but nevermind). But even he preferred to "BnZ", as this crowd would call it. (he himself said he didn't like turning fights, and he and Boelcke more or less pioneered the diving, speed attack)

The SPAD 13 was a BEAST. A WWI Jug. "Dove like a streamlined brick" and fast as hell. And very successful. The vast majority of Richtofens kills came in the Albatros, which was better at diving than turning (though the D.V had diving issues due to the Sesqui-Plane layout).

Sopwith knew the triplane was a dead end, so they went back to biplanes - less drag, better vis, more speed.

The best plane of the war, the Fokker D.VII (7) was feared because it was FAST, dove very well, could hang on it's prop, and on top of all that, was a great turner to boot. It's speed and climb were what made it so deadly and effective.

Pulling Gs, diving fast, rolling hard... these require lots of strength. Strength means weight. With low power, you have only 1 choice, suffer the drag penalty and box the wings with a second set of wings, to that the weight contributes to lift (and is a more efficient way of gaining strength, like a roll cage).

Stiletto-
11-08-2007, 09:39 PM
Good posts guys. M Gunz, I would play a WWI sim but there haven't been any good ones in years, I remember playing Red Baron II and it's physics failed in comparison to Wings of Glory, a sim 2+ years older. I also cut my teeth in flight sims playing the original Red Baron, did this online aswell, but my 2400 baud modem didn't cut it. I remember in the original Red Baron the SE5a was the fastest plane, I think it did 145mph in the game, though in Wings of Glory the Spad 13 was the fastest, I dunno if these were inaccuraices or just different variants between the games, not so important..

I remember using the SE5a on ballon busting missions in Red Baron, and as I'd circle around the ballons back and forth making my passes I'd get a trail of german planes on me, so I'd just firewall it until they got real small and make longer passes. So it's prevalent that speed is pretty much king, even in these old games. I don't remember using the vertical at all to try and get at an adversary though, I think the loss of energy was too much, but I could be wrong / game could have been wrong.

M_Gunz
11-08-2007, 10:34 PM
Until the 1.4-something patch around April-May of 98, RB2 wasn't at its best.
RB3D went gold with a cracked, exploit loaded FM but the MMP and Campaigns saved it.
I've been on servers with 80 RB3D players at once where who lagged was because of their
connect to the server and not server to me.

I never had Wings of Glory. Didn't have Flying Corps that had what was then a very good FM
but campaign so sterile it was dubbed Flying Corpse. Most combat flight sims seem to sit
between RB and FC for the extra between actions immersion.

WWI air war was a time of huge change and development of all aspects of air war.
The reversals in superiority of planes and tactics makes for a good game environment.
The Germans had even developed a sheet-steel armored plane just for attacking trenches
but it never hit production that I know of, the first of the true close tactical support
breed rather than lining up fighters and strafing the trenches.

If you can find Hell's Angels somewhere (AMC shows it sometimes) cheap or free then grab
a copy. If I could put all THAT in a box, even to just choices and cutscenes (do you want
to: A) stay in the barracks and sleep, B) eat supper, C) go to a bar, D) visit the USO?)
between briefings and don't forget flying missions -- I'd have one heck of a game.

M_Gunz
11-08-2007, 11:40 PM
Originally posted by BlitzPig_DDT:
It's sorta both El. To support a single wing with ailerons and the associated complexity would make things too heavy without adding lift. Rather than add dead weight, why not make it pull it's weight (so to speak)?

Wing thickness was key. The did not understand what is Reynolds Numbers since (1930?) and
scaled up from birds wings directly when they got past only surfacing the top layer at all.

The thin wings hit stall at a low AOA and making things worse, except for rigging the wings
are straight with no twist or change in foil from root to tip; the whole wing would stall at
the same time, not inner before outer.


Even a 110hp Oberusal could power a monoplane to some of the best performance of the war (and the LAST kill of it). http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Stilleto - Look at the Etrich Taube. Possibly the first bomber, and one of the fist war planes too. Not only beautiful to look at, and slow, and weakly powered, it was a mono-plane wing warper, that while fragile, could lift 2 people, plus some extra gear and even light bombs. Don't need 2 wings to do that. But it's also not going to go fast or roll hard - it would collaps like piece of newspaper.

Also, think they weren't going fast? The Pfalz D.XII, Albatri, SPAD, and even SE5a were about speed. More so the first 3. They could turn, but relative to what? The Dr.1 was ignored. It's fame comes from Richtofen (even though it SHOULD come from Voss, but nevermind). But even he preferred to "BnZ", as this crowd would call it. (he himself said he didn't like turning fights, and he and Boelcke more or less pioneered the diving, speed attack)

Eindekker zipped along at about 91mph in 1916, SPAD XIII made 135mph in 1918.
When they got SPEED up was in dives, IIRC from long ago, SPAD XIII could hit 200mph in a dive.


The SPAD 13 was a BEAST. A WWI Jug. "Dove like a streamlined brick" and fast as hell. And very successful.

It and the Pfalz copy of it were the FWs and Jugs. Not just for dive speed but for roll rate
unmatched. Long ago the Brittanica article stated that the wings were set anhedral, instead
of wingtips being slightly up, they were slightly down. Training losses were very high to
say the least, more than combat losses, all SPADs rolled like a round bottom canoe.
Consider you are going 120mph and want to change course 120 degrees left. SPAD flat turns
like a streamlined brick so you pull up vertical, roll onto course, pull over the top and
roll back flat now on your way back down. Pull over top uses gravity and you've slowed
enough that e-loss in the pull over is minimal, dive to complete returns your speed with
motor assist, total time maybe 5-6 seconds done aggressively.


The vast majority of Richtofens kills came in the Albatros, which was better at diving than turning (though the D.V had diving issues due to the Sesqui-Plane layout).

DVa was faster than DIII and heavier, the fuselage shell and airframe were stronger and more
power. Richtofen was a marksman and made many kills from long distance compared to others.
He was a hunter since he was young. Heavy DVa might have been more stable than DIII, I can't
say but can guess.

The Albs were energy fighters compared to some Allieds but angles fighters compared to others.
You wouldn't want to e-fight with a SPAD in an Alb and you wouldn't want to turnfight an early
to mid Nieuport. Ohhhh, no!

Really the Albs were well-rounded, useful fighters that had more firepower than many Allieds.
Not the fastest or the best turn or climb but average to good on all and two guns as well.


Sopwith knew the triplane was a dead end, so they went back to biplanes - less drag, better vis, more speed.

They used full length wings and fuselage. And the engine, mediocre. Look at what the Camel,
Dolphin and Snipe got. And I'd take that Snipe over the SPAD XIII if I had a choice.


The best plane of the war, the Fokker D.VII (7) was feared because it was FAST, dove very well, could hang on it's prop, and on top of all that, was a great turner to boot. It's speed and climb were what made it so deadly and effective.

Top speed 116mph. It was deadly because it had good speed and could turn and climb well.
It was very stable and easy to fly, any pilot could be good in one.

It had the thick Gottingen wings same as DrI. Lift was higher, critical AOA was higher and
the lift curve has a wider rounded top than the thin wings with sharp peak at stall. Result
is much more benign stall (though still hard and fast by WWII fighter standards) that you
don't have to be a top test pilot to dare push the edges in.

That was the plane that had to be surrendered specifically by name in the Armistice.


Pulling Gs, diving fast, rolling hard... these require lots of strength. Strength means weight. With low power, you have only 1 choice, suffer the drag penalty and box the wings with a second set of wings, to that the weight contributes to lift (and is a more efficient way of gaining strength, like a roll cage).

They built them like bridges. Even the externally braced monos used bridge construction
techniques.

Consider that with fixed props you have to twist the blade so that any any speed one part
is running with the most effience while the rest is not. The inside may be set so that the
blade AOA (at about 1000rpm) would be right from stopped to takeoff and the blade twist would
vary evenly so that the prop tips are right at some speed below but not far below maximum speed.

So you are stopped, the inner prop area is where most of your thrust is made and the tips
are stalled (still may be adding thrust but at high cost in engine drag), and when you are
zooming along the tips are making most of the thrust and the roots are producing low thrust.

Those props had very long blades but note they were limited as to thrust producing speed
ranges. It took 2-speed props to break that barrier so the payoff going biplane to mono
did not have such a great pan-out.

M_Gunz
11-08-2007, 11:55 PM
Originally posted by Stiletto-:
I don't remember using the vertical at all to try and get at an adversary though, I think the loss of energy was too much, but I could be wrong / game could have been wrong.

So much of the game is about building up and hoarding your energy, climbing to high alt because
altitude is the only long-term energy you can save much of.

But the late model fighters could build speed and alt through a series of dives and climbs.

A short foray into the vertical, rising up to do a wingover at lower speed (less energy lost
in the slower gravity assisted turn) and then dive to regain the stored (in alt) energy as
speed takes less time and energy than a flat turn.

Nose low turns are another favorite of mine if my speed is not great. Drop the nose and the
throttle (slower prop means less gyroscope to fight when starting the turn, IRL) then get the
turn started while you drop and bring the power back up as you rise back up to alt with more
speed than you started with (if it was high, I'd wingover) in general. The turn is gravity
assisted, you can pull more there than you dare in a level turn and get quick angle if you
also accept the e-loss at economy rate you get. You try that next time you are not catching
up in a level turnfight, drop nose and cross the circle. If the target does not see then he
will accuse you of cheating! That works WWI and WWII except the circles are bigger in WWII.

BlitzPig_DDT
11-10-2007, 01:42 PM
Originally posted by M_Gunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The best plane of the war, the Fokker D.VII (7) was feared because it was FAST, dove very well, could hang on it's prop, and on top of all that, was a great turner to boot. It's speed and climb were what made it so deadly and effective.

Top speed 116mph. It was deadly because it had good speed and could turn and climb well.
It was very stable and easy to fly, any pilot could be good in one.

It had the thick Gottingen wings same as DrI. Lift was higher, critical AOA was higher and
the lift curve has a wider rounded top than the thin wings with sharp peak at stall. Result
is much more benign stall (though still hard and fast by WWII fighter standards) that you
don't have to be a top test pilot to dare push the edges in.

That was the plane that had to be surrendered specifically by name in the Armistice. </div></BLOCKQUOTE>

116.5 with the weakest engine. (Mercedes)

At 185hp (BMW) it went 124 (and the SPAD 13 was only good for 130, with an extra 15hp, plus it didn't have near the climb or turn of the D.7).

With the (210hp) Austro-Hungarian (Austro-Daimler) it only went 122, the weight wasn't much different, yet the climb to 13,000' was 1.2 minutes quicker, so it was a climb prop (ability to hang on it even more so, with virtuall no loss in speed).

The D8 went 125 and got to 13,000' just .25 minutes later than the Austro-D7.

High and mighty Camel only went 116.5 with the 150hp engine (which was heavier than the 130 Cleget, only gained it about 1mph, and added even more torque and worsened turn - it was a pilot killer to begin with). Standard 130hp Camel was 115mph, climbed to 15,000' in 20.4min, whereas the Dr.1 climbed to 16,400' in 14.3 minutes and went between 105 and 115 depending on prop. Less torque, more lift about 200lbs less weight fully loaded.... But hey, the Brits wrote the history.

(funny thing is, many pilots preferred the SE5a over hte Camel, yet the Camel still has the glory. The f4u of The Great War. http://forums.ubi.com/images/smilies/59.gif )

harryklein66
11-10-2007, 05:59 PM
124 mph is the D VII(F) top speed at see level
whereas 130 mph is the top speed of the Spad XIII 220hp at 4000 metre.

At 2000m the Fokker D VII(F)top speed was 115 mph
and the Spad XIII 220hp 135.5 mph

The Spad XIII 220hp climb twice faster than the fokker D VII,
and the D VII(F) climb between 30-40m/mins better than the Spad.

BlitzPig_DDT
11-10-2007, 06:55 PM
I doubt much serious fighting was going on at 4Km without O2 masks. They suffered a lot of "altitude sickness" before they figured out what was going on.

The SPAD couldn't match the handling of the D7. Yet the D7 was right with the SPAD in speed and climb - it was more dangerous.

M_Gunz
11-10-2007, 11:22 PM
The DVII was a great all-arounder and more because you didn't have to be as good a pilot
to do really well in it as SPAD, Camel and to a lesser amount, the SE5-A.

The GAS could send up more numbers of highly effective pilot-and-planes with the DVII, it
was next level beyond the best the Allies had in terms of handling. It was as big a leap
as ailerons were to wing-warping.

M_Gunz
11-10-2007, 11:31 PM
Originally posted by BlitzPig_DDT:
I doubt much serious fighting was going on at 4Km without O2 masks. They suffered a lot of "altitude sickness" before they figured out what was going on.

The SPAD couldn't match the handling of the D7. Yet the D7 was right with the SPAD in speed and climb - it was more dangerous.

Contraire. There were pilots that went up after 2 seaters at 16,000 to 21,000 ft. There were
2 seaters built to fly higher with crew oxygen but I can't say if the engines had boost or were
just big and powerful enough to have 22,000 ft ceilings. But it was done. And there was action
between 12,000 and 16,000 ft -- young pilots dealt with it regularly while "Grandpa" Rickenbacher
did suffer from respiratory and ear problems over it, medically unable to fly at times. He was
in his late 20's. Funny but we had a guy 28 in our platoon in basic and he was called Grandpa
too! But then he looked a bit like Al Lewis, Grandpa on The Munsters.