Re: Tail surfaces - 109F versus 109E?
 

George was absolutely correct, but if You want to obtain full information on rudder - here you are. I hope I'm not violating any rules of our forum but if so I accept any penalty.

Re: Tail surfaces - 109F versus 109E?
 

Hello,
I am quite sure that the outlines of the E and F vertical tails were essentially the same. However - besides other considerable constructive changes - the rudder axis was moved aft by 39 or 40 mm on the F. This is shown by George Hopp's above Mtt. drawing (which yields 39 mm). The RAF drawing compares only the rudders and thus may falsely suggest that also the outlines of the two tails were different.
On other drawings the horizontal distance of the elevator axis and the rudder axis is given as 85 mm for the E and 125 mm for the F. This would yield an an aft movement of the rudder axis of 40mm, on the assumption that the tailplane did not only keep its vertical position but also its horizontal one.
Last remark: Once you know about the different positions of the rudder axis the different optical impressions of the ratio between the length of the fin and the length of the rudder on photos become striking.
Regards,
klemchen

Re: Tail surfaces - 109F versus 109E?
 

Let's be clear here. Aircraft manufacturers use precise plans and jigs when building their aircraft. We still do the same when building our aircraft today.

All the best,

Crumpp

Re: Tail surfaces - 109F versus 109E?
 

My query was on Pstrany's post, rather than George's, for he specifically wrote "builders drawings". Whether Messerschmitt or German manufacturers in general, he shall have to tell us (and every English grammar teacher will be crowing "Apostrophes do matter!")

(Little joke - I don't really expect all contributors to have perfect English.)

George is almost certainly wrong, in one sense, because it will not have been the RAF but the RAE (Royal Aircraft Establishment) who took so much effort to measure and compare the shapes. At least, it will have been done at their instigation, whoever took the measurements. I assumed George meant simply "the British".

Re: Tail surfaces - 109F versus 109E?
 

Despite Murphy's book the problem is that shapes were really different as it can be seen from Mtt' bauplans.

Look at athe attached files in my above post.

Well occasionally I also have rudder manufacturing and assembling blueprints not only general arrangement dwg I have posted earlier on 109E and some remnants of 109F/G rudder drawing.

They ARE different.

1. Rudder has different mounting points location. F/G/K rudder has 2 points
2. Rudder has different square and shape
3. Fin shapes are different also.

Re: Tail surfaces - 109F versus 109E?
 

Quote:

They ARE different. 1. Rudder has different mounting points location. F/G/K rudder has 2 points 2. Rudder has different square and shape 3. Fin shapes are different also.

I don't think anyone is disputing the fact that the different design variants of the BF-109E/F/G/K experienced design changes. That is silly to dispute.

I am and I believe Graham is also speaking about deviation and distribution of manufacturing errors. Using multiple blueprints of varying measurement for the same type is beyond stupid from both a business and an engineering viewpoint.

When they hit the assembly line floor and the jigs are built, they are NOT different.

Do not confuse the wealth of pre-production and even post production information with that used on the assembly line. The Luftwaffe aircraft are probably the most prolific in their design changes without a re-designation of the type. The FW190 for example had three different aileron hinges with at least 5 different structural designs for the aileron itself. If you understand the affect of hinge point changes then you understand the significance on the stability and control of the design.

The documents you have certainly fulfilled the task and conveyed the information the author wished whether that information was precise or relative. That does not mean that had anything to do with assembly of the jigs or the actual aircraft rolling off the production line.


All the best,

Crumpp

Re: Tail surfaces - 109F versus 109E?
 

Hello,
mmoustaf's drawings are real interesting. They confirm that the rudder axis for the F was moved aft by 39 mm: Its distance longitudinally from the main wing spar (i.e. from the bridge going through the fuselage to which the wing spars were attached) is given as 5262 mm for the E and 5301 mm for the F. According to the drawings, the elevator axis was in exactly the same place for both models, despite different construction of the tailplanes (two pieces for E, one piece for F).
I am not maintaining that the outlines of the vertical tail for the E and the F were the same. The difference of the fins was very slight, but the E rudder was longer than it should be according to my theory. However, there is a discrepancy between George Hopp's Mtt. drawing and mmoustaf's E drawing, also by Mtt.. On the former, the outlines for E and F are the same, and the length of the rudder is specified as 634 mm,
i.e. 19 mm less than on the latter and precisely 39 mm more than the 595 mm of the F rudder.
George Hopp's drawing was made by the flight characteristics department on January 27 in 1941, that of mmoustaf on September 13 in 1942, probably by the same department ("Fleig" stands certainly for Flugeigenschaften = flight characteristics). At that time no E was built any more, so the drawing cannot have been used as a basis for construction. But what was it for then? And how reliable are drawings by Mtt. anyway?
Regards,
klemchen

Re: Tail surfaces - 109F versus 109E?
 

Quote:

And how reliable are drawings by Mtt. anyway?

Like most firms the reports are most likely extremely reliable for the purposes intended by the reports author. The discrepancy comes when one tries to take that information out of context and apply it to something never intended.

The key is having the entire report as well as the context of its development. Good example of that is our engine restoration has dictated we marry both physical and documentary evidence to build a case for the FAA that our engine will be safe to run using the latest manufacturer’s recommendations available.

Quote:

But what was it for then?

Without the entire report we would only be venturing a guess. However several distinct possibilities exist including the investigation of a q-limit raise in the design, the reduction or elimination of Dutch roll, or a decrease in the directional stability stick force per G. These are by no means the only explanation possible.

All possibilities will start out on the slide rule with supporting documents illustrating the design changes.

All the best,

Crumpp

Re: Tail surfaces - 109F versus 109E?
 

For such case we can continue duscussion with two type of drawings and one sample:

- first is Mtt jigs and theoretical outlines for production e.g. plans used to prepare splines and templates. These drawings represent a part of complete set used to restore 109E now and dated 1939. Also some remnants of 109F/G plans are available - that set was used to restore 109G-6 in Moscow;

- second is a drawing from NII VVS report contains dimensions and outlines of a real production 109E obtained in 1939/40 by USSR. So we can see how different are jigs/outlines both discussed earlier from a real sample;

- third is real rudder of 109G and 109E which I could measure. It could take about two weeks because of my skydiving activities

So what way do we choose?

Re: Tail surfaces - 109F versus 109E?
 

We can also draw on our experience as well as three other Warbird restoration organizations representing the majority of the US Market for restoring both Allied and Luftwaffe aircraft.

Can you post those drawings?

Thank you!