improving the 109??

[Milosh]

Bf109 had a bar attached to the outer door.

 

[Shortround6]

Simple, wheel/tire pushes door shut. Gear drops and gravity lowers door.
Now what happens as the airflow changes over the door may be subject to question. Door flutters a bit?

And maybe the late 109 needed all the help it could get on the bottom of the wing to counter that wacking big bulge on the top of the wing.

 

[stona]

And maybe the late 109 needed all the help it could get on the bottom of the wing

It needed all the help it could get with the wing overall, and the rest of the aircraft! Gear doors are just one of many elements when we consider all the other factors contributing to the drag/surface friction of the wing.

Cheers

Steve

 

[stona]

One aerodynamic analysis I read suggested that a cleaned up Bf 109 G-6 would have been capable, theoretically, of 800kph.

And here is the argument for such a fantastic speed on such a theoretical aircraft. No such aircraft could be, or ever has been built

Cheers

Steve

 

[tomo pauk]

Hoerner's analysis shows too low speed with engine (obviously not DB 601A but 605A) making 1200 HP - even the cluttered G5 and G6 with gun bulges and gondola cannons were good for 620 km/h. The gondolas cost almost 20 km/h, so a 'clean' G5 and G6 will do 640 km/h, not 610.
Uncovered whell wells cost another 11-14 km/h. Going from half- to fully retracted tailwheel earns 3-4 km/h. link

Hoerner's analysis:

 

[drgondog]

A couple of comments about the Horner analysis.
First - the RN is for 380mph at 22,000 feet. 1.1x10^^7 is not "Max RN", but the RN at that velocity for that chord at 380 mph at 22,000 feet .
For example for 340mph, SL, Chord = 5 the RN = 1.5x10^^7

Second - I don't have HP at 22,000 FTH for Db601 but suspect it is close to 1100-1200 Hp - which is fine for the aero analysis. Nowarra gives DB 605 A at 1475HP @ 22,000 feet for 391mph at 3200kg/7056 pounds for the 109G

Using that profile and same 14% Exhaust Thrust ratio

T=.85(1475) (550)/(391*1.467) = 1202; Include Exhaust Gas T---> 1.14*1202= 1370 pounds Total Thrust
his original value = 1140 pounds

Dynamic Pressure q is 1/2 Rho V^^2 at 22,000 feet ----> .5(.00237)(.498)(391x1.467)^^2 = 194 psf
his original value = 184 psf for the lower top speed (380mph) at 1200 HP

D/q = CdS --------> 1370/194= Cd(172) ---> 7.06 sq ft flat plate Drag and Cd = .041
his original value = 6.2 psf and CD=.036

For an explanation for increase of Total Drag consider that 380mph at 22000 = 380/701 = .54M
At 391 the M= 391/701 = .56M and that the compressibility drag rise for parasite drag is exponentially increasing. It takes 23% more HP to generate 20% more Thrust to take the 109G up 391/380 = 2.8% in airspeed for the 109G for the example given.

Net of the discussion re: Horner's analysis. 1.) it is a good illustration of basic performance analysis approach which serves to give a student an understanding regarding how Thrust and Drag are derived given a set of specifications and physical flight attributes. 2.) the reverse process of component drag build up is a better approach for understanding how it is done in preliminary design as there is Zero flight data, only projections based on matching Thrust HP to Drag Total (estimates) to plot Horsepower Required vs Horsepower Available from SL through Ceiling.

What is shocking is that a Mustang at combat weight, with the same HP as the much lighter 109G, is 12% faster - illustrating a.) the starting low drag of the Mustang, and b.) less compressibility increase to basic parasite drag as both a/c move past .5M.

At low to medium speeds the lower W/L of the 109 gives it a relative advantage at same Hp for the Climb performance. At high speeds the advantage disappears because the 109 is approaching Zero Power Available 'delta' versus Power Required for level flight while the 51 has excess Power available.

 

[GregP]

Is it bent or was it made that way?

I ask only because I have seen some doors and other items that had non-90° drills and taps in them. They LOOK funny but were original. We have a Bell YP-59A Airacomet being restored to flight status, and our was the 7th YP-59A (tail number 777). As a "test mule" it had a LOT of "custom" modifications. When we looked at the canopy frame, there was a bottom plate that had been modified maybe 10 times and had some 8 holes in it that had all been patched with "nickel-dime patches." We just made a new plate with no holes in it. Looks new now.

No agenda here, just asking. Also not lecturing, just wondered because I simply misunderstood your statement.

Cheers.

 

[pinehilljoe]

An old issue of Wings/Airpower had an article on what it would take to make the 109 a 400mph class plane, The author listed simple changes that could have been cut into production. Smooth out line, retract the rear gear, full wheel covers, eliminate balance horns.

 

[gomwolf]

Bf109 is almost reached at it's limitation at 1944. Actually, Galland want to more Me262 than any other prop aircrafts at that time and that is proper way to luftwaffe I think.

If luftwaffe want better prop aircraft with liquid cool Dimler-Benz engine, they have to produce G.55 when they discussed it. Milch had interest that aircraft(because G.55 can use DB603 without major design change and actually they made G.55 with DB603. It's name is G.56 and it was quite good fighter aircraft.) but they giving it up because there productivity will be fall for a time, if they produce it.

 

[tomo pauk]

An old issue of Wings/Airpower had an article on what it would take to make the 109 a 400mph class plane, The author listed simple changes that could have been cut into production. Smooth out line, retract the rear gear, full wheel covers, eliminate balance horns.

I'm not sure that improving an already 400 mph plane (= Bf 109F-4 from Dec 1941; Bf 109G from mid 1942) to become a 400 mph plane is worth the trouble
Bf 109F-4 was already making 390 mph from mid 1941 on.

 

[Shortround6]

"Listed Placard"" range?????

Where in the cockpit was this "Placard" located????

Or was it next to the fuel filler????

 

[GrauGeist]

I love that picture and plane but it was never built because it was not that much of an improvement to be interrupting the production of the worlds best fighter plane at the time. ( I am sure this last will stir up some vehement argument, but the only real point is that the Me-109 shot down more planes than the next three types combined. Any argument that ignores this simple fact is wrong!)
As a silly aside, which Allied aircraft type downed/destroyed the most Axis planes?

I'm assuming that you meant "not put into production", because they built 4 of them.

The point being, is that it's design attempted to use aerodynamic lessens learned during the interim between the introduction of the Bf109 and the Me309's concept.

If you look closely, you will also see that the Me262 had some influence in it's design.

 

[Thos9]

Here's the 109V21 with a hi-vis cockpit cover (and a radial engine).

 

[Shortround6]

It was not usually located on the plane at all. It was printed in the sales brochure, or in the pilot's manual and is the number that we all see listed in all the books, etc.

From Merriam-Webster;
Full Definition of placard

1. 1: a notice posted in a public place : poster
   
   
2. 2: a small card or metal plaque
   

Some airplanes did have placards in the cockpit giving speed restrictions, like never exceed speed in a dive and/or not to exceed speed in rough or turbulent air.
Other restrictions may have been listed or had their own placards (like loading restrictions?).

There is no such thing as "Placard Range".

Flight manuals will usually give fuel consumption per hour in various conditions (speed/attitude and throttle settings) like this "Flight Operation instruction Chart"
http://zenoswarbirdvideos.com/Images/P-40/P-40FOIC.pdf

Please note that the P-40 could do about 309mph at 15,000ft using max continuous power which may be the same as METO (Maximium Except for Take-Off.) ?

Please note that according to the Flight Operation instruction Chart range can vary from 325 miles to 700 miles depending on speed and altitude with 3 intermediate ranges given.

A separate Chart would have been listed for the plane while carrying an under fuselage store (bomb/drop tank) to take into account drag.

I would also note that the according to at least one test on the P-40D it could do at 15,175ft 354mph using 3000rpm/full throttle, 335mph using 2600rpm/FT, 307.5mph using 2280rpm/FT and 290mph using 2200rpm/part throttle.

SInce the engine was allowed to run at 3000rpm and 44in boost for 5 minutes I rather doubt it took over five minutes to accelerate from around 300mph to 354mph. In other words from a high speed cruise (thirsty as it was) to full level speed.
It might have take 5 minutes to accelerate from 150mph to 354mph, or not. I don't know.

 

[GregP]

Is that you, Neoconshooter?

 

[CharlesBronson]

Do not include the P-51 in the list of hard to make planes of WW-II! It was the single easiest plane to manufacture in the war! Huge effort was made to make production of the plane fast and easy. But do add the Zero and P-38 to the list of expensive to make planes!

Certainly the P-51A and B could be considered easy to manufacture.... compared with a spitfire or P-38 but still itwas more complicated than a Me-109F4 or G2, the Mustang also was a 1 ton heavier more so it consume more raw materials. Some people wont agree with me but except the sophisticated V12 engine the me-109 was budget plane, the best "bang" for your reichsmark.

 

[GrauGeist]

The P-51 was "easy" to manufacture because the U.S. tapped into it's mass-manufacturing experience.

The Germans never caught onto this and thus the much needed fighters trickled off the assembly line in comparison

 

[CharlesBronson]

Well, with 33,000 airframes (and most likely 30,500 aircraft actually delivered) you cannot charge the Me-109 of not being mass produced. Actually I think it was the only weapon system of the III reich (along with MG42) designed from the onset to be manufactured at large scale. Germany had bigger problems in other industrial areas like tanks, railways, ships, etc.

 

[GrauGeist]

The problem with Germany, is they never took the mass-production model seriously.

And it wasn't until their situation was dire, that they actually started producing large quantities of aircraft (although the quality was lacking). Had they took this attitude in 1939 - 1940, then they may have been able to ward off combat attrition, although the lack of pilots and fuel in the latter half of the war would still need to be addressed.

 

[wuzak]

Is that you, Neoconshooter?

I believe that to be the case.