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  • Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.

    Post 16 Update

    Post 17 Warning

Classics Hangar's civi Messerschmitt

That's what I mean, you can read from authors claiming that pilots locked their slats, but I have yet to hear that from the pilots themselfs. Who knows, maybe there was one, but that doesn't make it a common practice.
The pilots sometimes talk about a scary moment when they deploy in an evasive manover but not really any mention about negative aerodynamical effects.
To be clear, they do not change the lift slope when they deploy, they extend the max AoA of that portion of the wing. My opinion is their main function is to force the aircraft to stall level instead of dropping a wing. The slats should allow the outer wing to stall 5 deg after the inner wing. In other words, it's hard to spin this aircraft.
 
Are you modelling independent slat operation on the Bf 108?

BTW it is a Bf 108, not an Me 108 as its design predates by several years the incorporation of Willy as the owner of the former Bavarian Flugwerke in July 1938 and it's renaming to Messerschmitt AG. The utilisation of `Me` for the Bf 108 is really a colloquialism applied as a result of generic interpretation, rather than the correct usage.
 
Mathias said:
That's what I mean, you can read from authors claiming that pilots locked their slats, but I have yet to hear that from the pilots themselfs..
Click to expand...

You have to be quick, Mathias! There are not many Bf (or Me but that VERY old news) 109 pilots left.
 
Mathias said:
That's what I mean, you can read from authors claiming that pilots locked their slats, but I have yet to hear that from the pilots themselfs. Who knows, maybe there was one, but that doesn't make it a common practice.
The pilots sometimes talk about a scary moment when they deploy in an evasive manover but not really any mention about negative aerodynamical effects.
To be clear, they do not change the lift slope when they deploy, they extend the max AoA of that portion of the wing. My opinion is their main function is to force the aircraft to stall level instead of dropping a wing. The slats should allow the outer wing to stall 5 deg after the inner wing. In other words, it's hard to spin this aircraft.
Click to expand...

HI

Interesting thread both the plane and the slats issue

So i asked my friend(93,still quite bright/Legion Condor up 1945,which flew Bf-108 both stronger and weaker version)

he says that he never experienced any slat problem.It increased the manouverbility a lot and only were a bit touchy if you fly hard sharp manouvers as the automatic deployment on the 108 was not as sophisticated as on the 109
He also never heard about locking them!

you can see here
http://109lair.hobbyvista.com/index1024.htm

Also he said according to Novotny (with him he flew in Russia for some time) this was the secret of the 109 (Hartmann never ported over to any other plane)

All the best

Roland
 
I wish my students were reading this. It's a good illustration of how to evaluate sources, and a practical example of why it makes a difference.
 
The problem is that even if it's only a few years back it's very difficult to keep a precise memory about details.
That's why I try to get only betatester which are current on the specific type. E.g the last time I flew a Super Cub was about 7-8 years ago. I wouldn't dare to make exact statements about how exactly she flew, roll rate, stall etc..!
My father was flying the Me 163 and I once we met with a few other Me 163 pilots and they were 'only' around 70 years old back then.
It was unbelievable how different their recollection about solid 'facts' back than was, and that concerning a type with only version!
 
sg38 said:
The problem is that even if it's only a few years back it's very difficult to keep a precise memory about details.
Click to expand...

That's a good point. But for the 109, at least, there are scores of first-hand accounts, Finnish as well as German. Even reading all of them, you can't say that something never happened (and Mathias was careful not to do that). But you can establish what was normal, and for a model that's what we want.
 
Great responses everyone, thank you!


sg38 said:
The problem is that even if it's only a few years back it's very difficult to keep a precise memory about details.
That's why I try to get only betatester which are current on the specific type. E.g the last time I flew a Super Cub was about 7-8 years ago. I wouldn't dare to make exact statements about how exactly she flew, roll rate, stall etc..!
My father was flying the Me 163 and I once we met with a few other Me 163 pilots and they were 'only' around 70 years old back then.
It was unbelievable how different their recollection about solid 'facts' back than was, and that concerning a type with only version!
Click to expand...

And that's exactly why one should be very cautious with every talk that is done on a subject, often it's just anekdotes. This is particular true for everything Luftwaffe-related, too many guys around with an agenda in this or that direction and way too many wannabe experts.
If the anekdotes fail to deliver a coherent picture, pure and cold math has to take over, and that's what Greg is doing with his flight modelling. The slats theme is a pet baby of Greg for ages and I'm really looking forward to what he's coming up with on the FM's. ;)
 
I think it's really difficult to even get an idea about the actual application of 'SOP's, field mods, maintainance problems etc for a plane which has been built more the 34000 times.
But I do agree of course that you need solid sources to work with during programming. Naturally original pireps and manuals are the first choice.
 
Right, unfortunately the German period manuals don't talk that awfull lot about flight dynamics so one needs to gather that from elsewhere, Rechlin tests, allied tests with some reservations, and of course Greg's DATCOM and Roscam maths. As I understand it the M$ flight model is build around those maths anyway in one form or another so that should bring us right on track. :)
 
Ken Stallings said:
BTW: I just noticed something from that big screenie just posted. This sucker has leading edge slats! That's mighty impressive and I did not before realize it did!

I bet that has a great positive effect on reducing stall speed.

Ken
Click to expand...

Stall speed was 61 km/hr (33 kts) and landing speed 85 km/hr (46 kts). The Bf 108 only needed 185 meters (607 ft) for take off and needed just 130 meters (427 ft) to land.

Cheers,
Huub
 
sg38 said:
Well, as they are only on the outboard wingsection, not much reduction in stall speed BUT they work independent of each other with a primitive failure prone mechanism.
So you were in for a nasty surprise when they opened unevenly at slow flight, at low altitude a killer!
One report states that the german astronaut Furrer was killed during an airshow when he lost a slat on the 108 during a high speed/low level pass.
Click to expand...

Actually, stall reduction is the primary purpose of leading edge slats. They normally deploy due to the onset of stall causing less air resistance than the force of gravity allowing them to deploy forward and down.

When they do deploy, they essentially become an avenue to air to maintain a better boundary layer with the main wing. In effect this increases the critical angle of attack which normally translates into a reduction in stall speed.

Slots: http://en.wikipedia.org/wiki/Leading_edge_slot

Slats: http://en.wikipedia.org/wiki/Leading_edge_slats

As you can see by the link, the type of leading edge slats on this Me-108 is an automatic type, as it deploys automatically as a result of aerodynamic forces working against gravity. All that has to happen is for the rails and bearings to be free. These types of slats can become dangerous if one side hangs up while the other deploys. In that case, you have asymetric lift, with the wing of the failed slat dipping down significantly as it will stall first, leading to a possible spin if not countered very soon.

Cheers,

Ken
 
huub vink said:
Stall speed was 61 km/hr (33 kts) and landing speed 85 km/hr (46 kts). The Bf 108 only needed 185 meters (607 ft) for take off and needed just 130 meters (427 ft) to land.

Cheers,
Huub
Click to expand...

Wow!

Now that's even more impressive to me than the speed. This was a more capable aircraft than I originally understood it to be.

Ken
 
Maiden flight in FSX. A bit too nude yet but the exterior is now in the paintshop.:wavey:

bf108_FSX_01.jpg


bf108_FSX_02.jpg
 
All this talk tempted me to buy the 190 late models.....wow...wanna talk about tricky flight dynamics. Nice planes but very tricky...landings are tough.....can't wait for the 108 though.
 
skyhawka4m said:
All this talk tempted me to buy the 190 late models.....wow...wanna talk about tricky flight dynamics. Nice planes but very tricky...landings are tough.....can't wait for the 108 though.
Click to expand...

The first thing the pilots had to learn when they converted from the 109 to the 190:
Fly this thing with two fingers only! The controlls are extremely light and the plane is very agile and responsive, stick forces don't exceed 14 kilograms at very high speed in a dive.
On an aside, the A-8/R2 Sturmjäger are bitches to fly with all the armor.
For comparison, the A-5 or A-6 are much more forgiving.
 
I noticed the differences actually. I've been mostly flying the F-9 variant I think it is? German types have always had a place for me. I was wondering......how do I get the tail insignia to make them historicly accurate?
 
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