Bf 109, trimming and Finns

[pasoleati]

Someone requested to post names of Axis/German pilots criticizing the lack of rudder in the 109. Well, how about Pekka Kokko who wrote the Finnish 109G-2 evaluation report? His report contains e.g. following criticism:
-cramped cockpit both in width and in height
-canopy swings to side
-wide canopy framing obstructs visibility greatly
-lack of in flight adjustable rudder and aileron trim tabs
-unretractable tailwheel
-blind flying instrumentation poor
-detachable wingtip joint has a gap on about 1 cm covered with fabric. This [fabric] tears off often before the VNE and this causes a danger of wing sking deformation

So, do we believe a wartime report more or a memoir of a stuttering old man 60 yrs after the event?

[Angus]

I belive it was Izzy.i.e. Kurfurst who asked me to provide it.
Funny enough as it is, I have read some autobiographies from German pilots, they really don't get so much into the 109's flying characteristics at all!!!!
Anyway, the Fins may be able to provide some more stuff.
Just read the Finnish manual of the 109G6, and I must say that the performance figures are not quite the same as presented on these boards for a 1943 aircraft.
I have another graph from German sources, late 1943, it works nicely with the finnish one.
What Izzy is usually presenting is the practically flawless and overboosted uber 109, be it so, or prove othervise.,,,,,;)

[pasoleati]

What is also surprising is that the report considers the plane to require large unobstructed airfield! Take-off distance itself is shortish, 350-400 m, but the initial climb rate with gear and flaps down is low (if falps are not used, TO distance is 150-200 m greater), i.e. the distance to clear 50 ft obstacle is long. Landing distance is also long for the plane has tendency to float before touch down.

[pasoleati]

Exact wording from the report:"For landing the aircraft requires a large field without even small surrounding obstacles for the aircraft glides extraordinarily long before touching down."

[HoHun]

Hi Pasoleati,

Good work finding those reports!

However, when evaluating them, you have to find something to compare them to.

That the climb angle is steeper than the glide angle is normal for the fighters of the time.

P-51D/K, 9000 lbs, sea level, sod-turf runway, no wind:

1400 ft ground run, 2100 ft to clear 50 ft obstacle

Landing, firm dry sod, 8000 lbs:

1300 ft ground run, 2200 ft to clear 50 ft obstacle

(From the USAAF P-51 manual.)

German Kennblatt figures usually are for grass runways, and for 20 m (66 ft) obstacles.

All manual figures usually have some safety margin, in the case of the USAAF manual it's 25%.

Note that the Finns had no high-performance plane in the class of the Me 109G to compare to, and the older, slower fighters they had probably had shorter take-off and landing runs, so it was important to note the difference.

Regards,

Henning (HoHun)

[niklas]

-cramped cockpit both in width and in height

I once read that german pilots taller than a certain height ( 1.73m?) actually were ordered to fly the 190 later.

-canopy swings to side

Don´t see the problem here. You can´t open it in flight but why should you anyway? For bailing out the possibillity to opebn/ detach the canopy was definitly tested and cleared. Many german pilots bailed out successfully.

-wide canopy framing obstructs visibility greatly
Agree. Stiff frame for emergency landings / rollovers though.

-lack of in flight adjustable rudder and aileron trim tabs
Only aircrafts over 5tons required rudder and aileron trim in germany.

-unretractable tailwheel
G2 already?

-blind flying instrumentation poor
Artificial horizont was there, wasn´t it? Don´t know about the possibillities of radio navigation. What in detail was missing?

What exactly is the distance to clear a 50ft obstacle? Takeoff distance usually INCLUDE the distance to pass a 20m obstacle.

Groundeffect (floating) affects all aircrafts. When the 109 glides extraordinary long then it´s a nice hint about the aerodynamic efficience of the 109, especially because it´s wingloading was on the higher side compared to contempory fighters in 42/43.

niklas

[MiloMorai]

Originally posted by niklas


-canopy swings to side

Don´t see the problem here. You can´t open it in flight but why should you anyway? For bailing out the possibillity to opebn/ detach the canopy was definitly tested and cleared. Many german pilots bailed out successfully.

-wide canopy framing obstructs visibility greatly
Agree. Stiff frame for emergency landings / rollovers though.

-

There was problems jettising the canopy and the Radinger/Otto book reports on this.

How does one get out of the a/c when upside down if the canopy will not open. Don't forget there is a 400l gas tank right above.

[BlauK]

Originally posted by pasoleati
Exact wording from the report:"For landing the aircraft requires a large field without even small surrounding obstacles for the aircraft glides extraordinarily long before touching down."

Qualitative report is always comparative to some basis. It is quite natural to make that kind of remarks when thinking of all otherf fighters FAF was using before 109:s.

Large FAF airbase would not come even close to a large RAF or USAF airbase AFAIK Some LW pilots who had to use a FAF base temporarily were quite surprised of their small size.

[Charge]

"the aircraft glides extraordinarily long before touching down"

That is why even after the war the pilots (in Finland) were taught to pull the slats out before landing as the a/c could be brought down more slowly and on shorter distance.

-C+

[Grendel]

This report demands some notification to what the plane was being compared. The previous primary fighter types of FiAF were the Brewster B-239, Curtiss Hawk 75 and Fiat G.50. Compared to those the plane was much different beast, lacked aileron trims and required more space for landing and takeoff. After some time the Finnish pilots seem to have used mostly carrier style landings, coming in slats out, in shallow turn and sitting down with 3 points, then stopping quickly.

The canopy did have emergency jettison system, btw. But of course, what do you do if it doesnt work? Is there any matter if the canopy is jammed which way it opens?

Btw largest complaint about the canopy was the neck armor in the old canopy. It was badly positioned - and killed pilots in emergency landings. It was great news for them, when the G-6 had a better rear armor, that wasn't attached to the canopy itself.

[Kurfürst]

Originally posted by MiloMorai
There was problems jettising the canopy and the Radinger/Otto book reports on this.

How does one get out of the a/c when upside down if the canopy will not open. Don't forget there is a 400l gas tank right above.

Uhum. Radinger Ottos book in fact gives details of canopy jettison test with the later Erla Haube. Jettisoning was w/o problem when jettison levers operated in the right order, the tests were specifically about what if the pilot operates the levers in wrong, exact reverse order than he should... during the tests the canopy would open in many cases, but would remain attached to fuselage etc.

And as a result of the test the jettisoning trials, the canopy could be jettisoned reliably even if the levers were operated against prescribed instructions...

In other words, Milo is represanting a *very special version* of the original source - as always.

Otherwise... I have read Spitfires had a crowbar in the cocpit as standard equipment (you may guess the reason), and the book 'Fighters' also mentions that several RAF pilots during BoB carried a pistol with themselves, in case the Spit catches fire, to be used as a 'painkiller'... the movie Dark Blue world has also a nice scene of what happens if a Spitfire`s tank, 85 gallons mounted right in front of the cocpit, gets holed.. you`d literally swim in the petrol.


-cramped cockpit both in width and in height

True, as on other WW2 fighters.

-canopy swings to side

And? So does on Me 262.

-wide canopy framing obstructs visibility greatly

Stiegler, Hanna didn`t find it very restrictive otoh.

-lack of in flight adjustable rudder and aileron trim tabs

what niklas said. Other 109 pilots didn`t complain about it.

-unretractable tailwheel

Tailwheel WAS retractable on F-1, F-2, F-3, F-4, G-1, G-2, G-3 and G-4. If Kokko flew a plane that was w/o one, it comes as an atypical special case, or a very late production a/c.

-blind flying instrumentation poor

Considering we speak of a daylight fighter, what`s the surprise ? Otherwise it had the same thing as other fighters of the time for blind flying - artifical horizon etc. 109s built as bad weather variants had full instrumentation for nightflying, as well as autopilot, and from 1943 extra electrical navigation equipment, DF radio, and the Y-system that was used to navigate LW bombers over English nights w. hundred meter accuracy.. I am not aware if similiar was ever mounted on allied planes.

btw, Kokko`s report also mentions the G-2 climbs at 4900 fpm with 1.3ata, 30 min rating.

[Karnak]

Originally posted by Kurfürst
-cramped cockpit both in width and in height

True, as on other WW2 fighters.

Moreso than the vast majority of WWII fighters.

[MiloMorai]

Oh Barbi.

Test report # 109 18 E-43, dated 2-11-43

"In spite of the repeated improvements to the canopy jettson system of the 109G, complaints were still being received that the canopy refused to jettison at all or did not do so without problems."

It then goes on about fixes, but finishes with:

"It appears that this type of jettisoning mechanism will offer certain advantages, provided a design solution can be found to prevent the pilot becoming hung up on the levers while entering or leaving the cockpit."

It should be noted that the test was not done above 350kph(217mph).

Again, we an example of Barbi's reading inability.

LOL Barbi. I did not know that Europe had 100% cloud free skies, 100% all the time.

[HoHun]

Hi Karnak,

>Moreso than the vast majority of WWII fighters.

Do you have any dimensions? I'm just asking because we've had this debate over and over again, and I believe actual numbers might improve the quality of this round ;-)

Regards,

Henning (HoHun)

[Kurfürst]

Messerschmitt AG
Augsburg
Test Report
No. 109 18 E 43
Canopy Jettisoning 109 G
Flight Test Dept.
Date 2/11/43
Cause:
In spite of repeated improvements to the
canopy jettisoning system of the 109 G,
complaints were still being received that
the canopy refused to jettison at all or did
not do so without problems. Further jettison
trials were subsequently carried out,
the results of which appear below.

Test Procedure:
A normal G canopy with the markings No.
109.135-135-002 and 109.117-003 was installed
on the test-bed. In addition, the canopies
were fitted with a relief spring with
the marking No. A 17729 Z. Jettison trials
were conducted with the above-named
canopy.

Result:
The experiments were carried out as follows
based on various theoretical considerations.
First, the normal canopy lock was
opened and then the jettison lever pulled.
This sequence was chosen in spile of the
fact that there is a placard in the cockpit
which specifies that the lever be operated
in exactly the opposite sequence. Theoretically,
it is impossible to first pull the jettison
lever and then unlock the canopy, since
when operating the jettison lever the pilot
must place his head in the forward part of
the cockpit for safety. It is then no longer
possible to operate the canopy lock, since
the canopy center section may fly off to the
side at any lime after the jettison lever is
pulled.
In the first experiment the canopy lock
was activated at a speed of 350 kph and a
yaw angle of 10 degrees. The canopy center
section jammed. When the center section
was knocked over the limiting wire
snapped and the canopy struck the side of
the fuselage and then remained hanging.
As a result of the impact the two pins on the
right side of the canopy were so stressed
and bent that releasing the jettison lock was
no longer possible.
Subsequently, a forced landing was
made at Lechfeld with the canopy section
hanging to the side. The jettison procedure
may be seen on Page 4.
After the normal jettison procedure
failed to function smoothly, additional jettisoning
assistance was installed based on a
proposal from flight testing. As depicted in
Illustrations 1 and 2, the upper end of the
lever on the rear part of canopy 109.117-
003. which activates the locking bolts, was
lengthened.
A cable was attached to the lengthened
lever and the rear wall of the canopy (Illustration
3). At a specified opening angle (after
the limiting wire is broken) this pulls the
locking pin. This ensures that the center
section cannot swing out and bend the
locking pins. At the same time, the cockpit
center section is placed in the wing's downdraft
and is thus guaranteed to fly away beneath
the wing. The following page contains
a description of the jettison procedure
with the additional release mechanism. Installation
of the additional pull cable is
seen only as an interim solution to be retrofitted
in the 109 G cockpit. It can easily be
installed by the units themselves. For an
eventual series introduction Herr Caroli's
28
29
Canopy Jettisoning Process
Canopy is depicted as per Drawing No.
109.135-002 and 109.117-003. Also, the
relief spring drawing-number A 17729 Z is
installed.
The jettisoning procedure depicted below
took approximately 0.3 sec.

Canopy Jettisoning Process

Canopy is depicted as per Drawing No.
109.135-002 and 109.117-003. Also, the
relief spring drawing-number A 17729 Z
and the flight department's additional release
mechanism are installed.
The jettisoning procedure depicted below
took approximately 0.7 sec.

Flight Report No. 980/298
Bf 109, W.Nr. 160031, CM + ZD.
Pilot: Willemsen
Assignment:
To demonstrate trouble-free jettisoning of
canopy. (Complaints from front-line units)
1st Test
(23/9/43)
State of aircraft:
Canopy center section with rubber sealing
and compensating spring. Airframe otherwise
standard.
Result:
The canopy lock was released in straight
and level flight at a speed of 350 kph. Afterwards
the folding canopy immediately
opened to the right, the restraining wire immediately
broke, and as a result the canopy
struck the right side of the fuselage. Jettisoning
the canopy by pulling the emergency
jettison lever was no longer possible,
because the forceful opening of the canopy
bent the locking bolts. The subsequent
landing with the canopy hanging to the side
proposal will have to be adopted. This calls
for the two pins on the right side with
which the canopy center section is mounted
in the front and rear sections of the canopy
to be replaced by two claws. At certain
opening angles the claws no longer retain
their grip on the front and rear sections of
the canopy, and thus the canopy center section
can fly away below in the same way as
shown in the jettisoning procedure. A
memo has already been sent to BAL 109
informing them of the above proposal and
the interim solution by means of a pull cable.
It is to be assumed that the above improvement
can be introduced by the units
quickly.
Herr König of Erla Antwerp has already
designed and flight tested a jettisoning
mechanism for the improved view canopy,
in which the center and rear sections
are replaced by a single piece. It appears
that this type of jettisoning mechanism will
offer certain advantages, provided a design
solution can be found to prevent the pilot
becoming hung up on the levers while entering
or leaving the cockpit.

Augsburg, 2/11/43
FAV-A/Kal/Ka.
was uneventful. On the ground great force
was required to pull the emergency jettison
lever.
2nd Test
(5/10/43)
State of aircraft:
Additional cable on the canopy, which
opens the lock after the limiting wire is broken.
Otherwise as in 1.
Result:
The canopy lock was released in straight
and level flight at a speed of 350 kph. Afterwards,
the folding canopy immediately
opened to the right and the restraining wire
immediately broke. As the canopy opened
further, the additional cable released the
locking bolts and the canopy with rear section
was jettisoned smoothly. A detailed report
on the experiment with photos of the
jettisoning is being issued by FAVA1.
Augsburg, 7/10/43
FAFb/Wi/He.



Selective storytelling, as always.