What Bf.109K4 do we have anyway?

[MiloMorai]

1,98ata K-4s were rare but K-4s using C3 were not.

[Xasthur]

Originally posted by MiloMorai
1,98ata K-4s were rare but K-4s using C3 were not.

What are your sources?

[MiloMorai]

Originally posted by Xasthur
What are your sources?

This board for starters. Try the search option.

There was ~1700 K-4s built but only 4 Gruppen were authorized to use 1.98ata. These 4 Gruppen had ~150 109s of various models with about half operational. No one has come up with a number for 1.98ata converted K-4s.

[Charge]

Which one is more important, the technical ability to run on increased ATA, or the historical availability of such fuel?

If there were units operationally running on C3 and 150oct why can't we have both since both engines could operationally do it?

Or is the "in numbers more representative" model preferable?

-C+

[Xasthur]

Light perk on the 1.98 ATA version?

[TUXC]

IMO the best eventual solution is to have the 150 octane fueled Spitfires, P-51s, P-38s, P-47s, and Mosquitos and the 1.98ata 109K all perked to some extent. That way everyone gets what they want, but the higher boost versions won't take over the MA.

[Kev367th]

Unless some more info has come to light, as far as I am aware there is no HARD evidence that shows even 1 K4 flew with 1.98ata.

Lots of -
could of's,
we can 'safely' assume,
might of,
possibly did.

There is no doubt they would have liked to have 1.98ata, as per the commonly shown document.
Another document dated 3 days later shows them still using 1.8ata, and this is at the end of March 1945.

So given all the supply problems (fuel and plugs) is it even likely it happened considering the 190's HAD to have C3 fuel.
Once/if converted for 1.98ata the K4's couldn't use B4 fuel anymore, at 1.8ata they could use B4 or C3.
Neither was it a simple mod back to B4 standards (from Butch who is a 109 expert).

They did have however a operational testing group of 109G's that did use 1.98ata starting in Jan 1945. (don't know how long it lasted).

It's the same for K4's with Flettners -
Pics show them.
Not one pic has surfaced that show the actuating rod, in fact they were locked shut.
So the next argument was "well pilots could have asked for them to be unlocked"
I suppose they could, nothing to show they EVER did though.

Check back through the threads for plenty of discussion on these topics.


Big difference is there are sqn line books, pilot logs etc that show -
Spit LFIX - 150 octane May 1944
Spit XIV - 150 octane July 1944
Whole of 2TAF cleared for 150 octane Dec 1944.

[Charge]

"Unless some more info has come to light, as far as I am aware there is no HARD evidence that shows even 1 K4 flew with 1.98ata."

What is the hard evidence you require? There is a chart on Kurfy's site of units cleared for use of 1.98 ATA and AFAIK it is the same chart as in a book (not written by Kurfy btw).

And what friggin' flettners? I've never heard of 109s having flettners nor seen a picture. I see no immediate advantage of having flettners in 109 compared to flap/slat system it normally had.

-C+

[MiloMorai]

Originally posted by Charge
"Unless some more info has come to light, as far as I am aware there is no HARD evidence that shows even 1 K4 flew with 1.98ata."

What is the hard evidence you require? There is a chart on Kurfy's site of units cleared for use of 1.98 ATA and AFAIK it is the same chart as in a book (not written by Kurfy btw).

And what friggin' flettners? I've never heard of 109s having flettners nor seen a picture. I see no immediate advantage of having flettners in 109 compared to flap/slat system it normally had.

-C+

That is not 'hard evidence'. Cleared does not mean implemented.

for Barbi though, 'cleared = used by the LW; cleared = not used by the Allies'

Geez Barbi went on and on and on about Flettners. If not here, it was over at Ubi.

The rudder on the K-4 used a Flettner tab so I don't know how you could not have see them.

[Kev367th]

Originally posted by Charge
"Unless some more info has come to light, as far as I am aware there is no HARD evidence that shows even 1 K4 flew with 1.98ata."

What is the hard evidence you require? There is a chart on Kurfy's site of units cleared for use of 1.98 ATA and AFAIK it is the same chart as in a book (not written by Kurfy btw).

And what friggin' flettners? I've never heard of 109s having flettners nor seen a picture. I see no immediate advantage of having flettners in 109 compared to flap/slat system it normally had.

-C+

That is the chart I mentioned in my previous post.

Another document which shows 3 days later that units were still using B class fuel.
I believe Mike over at Spitfire Performance still has copy of it.

That leaves 6 weeks till the end of the war (with fuel / spares shortages) to modify all the units he is claiming were done.
Kurfy wouldn't have it that Mk I spits used 100 octane during the BoB thats with a 3 month (not 6 week) lead period during relative calm.
He has some good info, but stretches things on the odd occassion.

[Neil Stirling]

There was a proposal that formed part of w OKL, Lw.-Führüngstab, Nr. 937/45 gKdos.(op) 20.03.45  to convert some 109K-4 units to 1.98ata, however a proposal remains just that, an intention a suggestion.

Neil.

[Charge]

"Another document which shows 3 days later that units were still using B class fuel."

Well, I don't find that hard to believe. Technically they were cleared to use 1.98 ATA and that is enough for me.

***

Sorry, I misunderstood and was talking about something else in case of Flettners.

"An arrangement called the Flettner tab had been tried on large airplanes as far back as WW I. This device, which was invented by Anton Flettner, the same man who invented the Flettner rotor for propelling sailing ships, consisted of a small tab mounted at or behind the trailing edge of the main control surface. The pilot's control was connected just to the tab. When the tab was deflected, it moved the main control surface in the opposite direction. Because the hinge moment to deflect a control depends on the product-span times chord squared-it is apparent that very large reduction in the pilot's control effort could be obtained."

The rudder was very effective even in earlier 109s so I cannot see any sense in implementing a Flettner control in its rudder. Maybe elevator but not on rudder...

A useless modification IMO.

-C+

[MiloMorai]

Guess you have not had the pleasure of applying rudder for any amount of time  above the cruise speed the trim tab on the rudder was adjusted for.

There must be some truth to the story 109s pilots had one leg fatter than the other for Mtt to have a rudder Flettner on the 109.

Flettners were also tried on the ailerons. There is suppose to be ~200 K-4s produced with aileron Flettners (Oli Lefebvre). These proved to make aileron control too oversensitive.

[Angus]

With the "tail twist", you would not need the "boot" at a certain speed, typically the cruising speed right?
So, you would get legs excercize on both legs, typically more on the "high speed" leg right? Slow speed (under the nil, - cruise) would need opposite rudder.
Correct?

I'd much more have the trimmable one...

[Charge]

"Guess you have not had the pleasure of applying rudder for any amount of time above the cruise speed the trim tab on the rudder was adjusted for.
There must be some truth to the story 109s pilots had one leg fatter than the other for Mtt to have a rudder Flettner on the 109."

It is true that above or below the set speed of trim tab you had to constantly apply pressure on rudder to keep the plane flying straight. So why not just install a simple trim tab adjustable from cpit but to change totally the more complex control system is beyond my reasoning. Also if the rudder becomes too light in slow speeds there's always a risk of over controlling, and even more so if the controls and not balanced enough.

I don't recall reading about the differences pilots experienced when changing to K. So were they indeed locked?

The method of flettners require the only to control of the tab, and the tab movement moves the rudder surface. So if the tab is locked the control wires need to be switched to rudder.

-C+