Author Topic: New 109's (Read 3039 times)

LRRP22 · « **Reply #30 on:** October 12, 2005, 01:13:17 PM »

Quote

Originally posted by Kurf�rst
And frankly, this is what I'd expcept. Regardless how you boast on how 'ultra clean' it was, there was nothing special about it. It looks like any other bombrack [/B]

Don't you think that maybe most bomb racks looked the same for a reason? Don't you think they would look more like gondolas, if the gondola shape was more efficient?

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frank3 · « **Reply #31 on:** October 12, 2005, 02:29:00 PM »

I think they just tried to make the fairing as small as possible, without concerning too much about the aerodynamic loss

LRRP22 · « **Reply #32 on:** October 12, 2005, 02:59:30 PM »

Quote

Originally posted by frank3
I think they just tried to make the fairing as small as possible, without concerning too much about the aerodynamic loss

I'm sure they were designed to be as efficient as possible for the loads they were designed to carry. You can bet that if a different, but bigger, shape was more efficient, then they would have been bigger.

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Krusty · « **Reply #33 on:** October 12, 2005, 08:24:42 PM »

Not so. They knew that faired DTs were better aerodynamically, but the only plane that ever got them was the Mossie. Just because they DO something doesn't mean that they take into consideration every aspect. The plane flew pretty fast enough, they didn't give a crap if it lost 10mph because of bomb racks. The bomb racks were necessary.

In general, aerodynamics were still in the fledgling stages in WW2. Hell it took the RAF til 1945/46 to figure that giving the spitfire WHEEL DOORS would add 5mph. Something as simple as a spit climbing with closed radiators (rigged closed) gave it an additional 500+ fpm climb rate. Drag is a subtle thing. Why argue why a pony has "this" drag and a 109 has "that" drag. They just *did*. Fact. End of matter. Nobody knew any better.

I'd personally argue that it wasn't until the speed race after the war that people really sat down and started thinking about what slows a plane down in flight.

Squire · « **Reply #34 on:** October 12, 2005, 09:07:49 PM »

They knew perfectly well what caused drag.

Look at the world air speed record holders in the 1930s, the Schneider Air Races, and all the rest. The Germans, British, French, Italians, Americans all pioneered very sleek drag free designs that went very fast in the inter war years.

It was the 1940s, not the 1490s.

"Hell it took the RAF til 1945/46 to figure that giving the spitfire WHEEL DOORS would add 5mph."

-The Spit VII, VIII, XII and XIV all had wheel doors, the 109G-6, 109G-14, and 109G-10 did not. Fixed tail wheels were simply a design decision for combat a/c in WW2, some felt that the retractable tail wheel was just something else that could fail upon landing (which they sometimes did), and cause damage to the a/c. It wasnt considered that big a deal.

They did care about a loss of 5-10 mph, but as you say, bomb racks were required, as were DT racks, just as gondolas were, and they were used. They were combat a/c and drawbacks like that were just the cost of doing business. You cant fighter-bomb without racks to carry them.

GRUNHERZ · « **Reply #35 on:** October 12, 2005, 09:17:42 PM »

He meant doors to cover the outer half of the mainwheels.

Squire · « **Reply #36 on:** October 12, 2005, 10:11:51 PM »

Oh those, well, same thing, they were an extravegance that were not considered crucial, and it had nothng to do with not knowing about drag in WW2, thats for sure. 109K-4 and Spit Mk.21 were the only varients of those two to have them (they also both had retractable tail wheel).

Krusty · « **Reply #37 on:** October 12, 2005, 11:59:54 PM »

It was only after tests that spanned the entire war that they came out with a report on what caused drag (and how much). They did not know about the wheel doors before then. They might have thought it was negligable or not important (seeing that the fighters flew, flew well, and got kills, etc, what does it matter if they have doors?).

Also, what won speed races was power to weight and wing shape. Messerschmitt designs had one thing, a really strong (for the time) engine, a thin, modern, wing, and a lightweight frame. They were ungainly as hell and boxy. Not very aerodynamic, either.

Debonair · « **Reply #38 on:** October 13, 2005, 01:18:06 AM »

On the topic of aerodynamics, anyone ever wonder if induced drag reducing winglets (like those on a 777) would have improved the manuverability of WWII fighter?

Karnak · « **Reply #39 on:** October 13, 2005, 02:11:17 AM »

There was a lot of effort by all combatants to reduce drag. They all knew about it and they all fought to minimize it. Look at the cowling on the A6M and Fw190. Those are both designed to reduce the drag of a radial engine. The thin wings on the Spitfire are a direct legacy of Mitchell's experience designing aircraft for the Sneider Trophy races. The compact form of the Bf109 is to minimize drag. The P-51 was designed from the start to have less drag than contemporary fighters. The Mosquito's whole shape is likewise to minimize drag as was the Ki-46's. The only real change from the La-5FN to the La-7 is to reduce drag.

In all these cases they did their best within the limitations that were imposed on the design team. Sometimes those limitations were due to the mission of the aircraft, sometimes due to budgetary requirements and sometimes they had to sacrifice to keep it simple enough to build and operate effectively.

Aerodynamics were not a new concept.

Charge · « **Reply #40 on:** October 13, 2005, 03:18:07 AM »

"On the topic of aerodynamics, anyone ever wonder if induced drag reducing winglets (like those on a 777) would have improved the manuverability of WWII fighter?"

Why would they improve maneuverability?
They are there to reduce drag.

-C+

Debonair · « **Reply #41 on:** October 13, 2005, 04:04:41 AM »

Specificly they reduce induced drag by limiting the creation of wingtip vorticies.
So, to be more specific improve manuverability in a low speed turning contest.
Reduced drag, I was thinking, would mean more excess thrust or more lift, potentialy including the horizonal component of lift which makes a 'plane turn.

Debonair · « **Reply #42 on:** October 13, 2005, 04:48:36 AM »

...so does the above make sense or nonsense?

Angus · « **Reply #43 on:** October 13, 2005, 05:48:49 AM »

Well, racks or no racks, the P51 is very fast for its weight and HP's.
Similar power to what - the 109G-6? Heavier, but yet faster?
Anyway, I'm eager to see and try the G-14, - could be my next pet in AH

Wonder what skin it's gonna get. I vote for Hartmann's!!!!!

Charge · « **Reply #44 on:** October 13, 2005, 08:35:45 AM »

Debonair, I would say that the way you described them especially in slow speed their effect is very small if it exists at all.

They do help the contemporary airliners to save fuel at their normal cruising speeds by reducing the wingtip vortices and their effect on drag.

-C+