Leading Edge Slats on the Me-109

[Crumpp]

you will stall her of course when you do a mistake and lose control

Again, they act like training wheels on a bicycle. In otherwords, it should be EXTREMELY difficult to spin the aircraft and very easy to recover.

once the a/c enters the spin

The advantage of the slats is in preventing spins. Find a report on the spin characteristics of the Bf-109.

There is an engineering reason there is not one.

[Robo.]

So are you saying that the 109 was unspinnable? Even if the pilot made a mistake?

I see the point that the a/c in game is now too difficult to recover and I agree it should be addressed.

[SlipBall]

Originally Posted by Robo.

So are you saying that the 109 was unspinnable? Even if the pilot made a mistake?

I see the point that the a/c in game is now too difficult to recover and I agree it should be addressed.

I find it easy to recover, trick being to act very fast with opposite rudder, & pitch throttle, to protect the engine

[NZtyphoon]

Originally Posted by Crumpp

Again, they act like training wheels on a bicycle. In otherwords, it should be EXTREMELY difficult to spin the aircraft and very easy to recover.



The advantage of the slats is in preventing spins. Find a report on the spin characteristics of the Bf-109.

There is an engineering reason there is not one.

Interesting in light of the fact that one of the reasons the 109 was chosen over the He 112 was because test pilot Hermann Wurster was able to demonstrate a series of spins, 21 to port, 17 to starboard, before a group of Luftwaffe officials. Clearly the 109 was easy to recover from spins - the E probably a little more difficult than a Jumo engined prototype - but the slats were not some miracle cure for spins.

[Crumpp]

Hey check it out......the slots resulted in far superior stall characteristics such that with the CG loaded fully aft, the airfract was spun in a tail heavy load safely!

Wow, that is good information. We I teach spins, the CG must be as far forward as possible for a very good reason.

Normally, a rearward CG spin is extremely dangerous and something to be avoided. To intentionally load the aircraft to its rearward limits and then spin it speaks volumes of the confidence in the slat operation.

Entry into a spin is much easier at any aircraft rearward CG limit but recovery is much more difficult if not impossible because the spin will flatten.

The aircraft showed no tendency to flatten the spin even at a rearward CG.

That pretty much says it all and proves the value of the LE slats.

[Robo.]

Originally Posted by Crumpp

Hey check it out......the slots resulted in far superior stall characteristics such that with the CG loaded fully aft, the airfract was spun in a tail heavy load safely!

Wow, that is good information. We I teach spins, the CG must be as far forward as possible for a very good reason.

Normally, a rearward CG spin is extremely dangerous and something to be avoided. To intentionally load the aircraft to its rearward limits and then spin it speaks volumes of the confidence in the slat operation.

Entry into a spin is much easier at any aircraft rearward CG limit but recovery is much more difficult if not impossible because the spin will flatten.

The aircraft showed no tendency to flatten the spin even at a rearward CG.

That pretty much says it all and proves the value of the LE slats.

So in your opinion, what exactly is wrong with the Bf 109 we have in game regarding slats operation and spin recovery?

[Crumpp]

It is way too easy to enter a spin and the stall behavior is too violent.

The account Nztyphoon only relates the aircraft being spun at only at the most aft CG location.

Willy Radinger and Walter Schick's books on the Bf-109 development and testing go into some detail on the spin testing of the Bf-109.

Spin entry and normal recovery was a requirement in the RLM specification for a new fighter that the Bf-109 was designed under. They actually modified the Bf-109V1 for this purpose.

The testing experimented with different size slats as well as pilot deployable and retractable slats. It was a very expensive test because of the modifications required to meet the specification

CG location not only changes stall speeds in any aircraft, it effects both spin entry and recovery. At the forward limits, the aircraft is most difficult to spin and recovers the easiest. Aft CG limit is the opposite, easy to spin and difficult to recover.

Once more, we have two basic categories of CG limits. It is just like the difference between an Aircraft Flight Manual and Pilots Operating Handbook.

When the Pilots Operating Handbook covers only a particular model or type of the aircraft, the Aircraft Flight Manual is very specific to the aircraft.

http://www.differencebetween.net/mis...n-afm-and-poh/

On every aircraft type there is a CG limits range published in the Type Certificate that covers the particular model or type. Each specific aircraft has a weight and balance sheet the cover the specific limits of that serial number aircraft. Like the Aircraft Flight Manual, that weight and balance is part of the airworthiness of that serial numbered aircraft.

So while a production type will have a set range, not every aircraft in that type will have the same CG limits.



My first airplane had LE slats and it was a hot topic on the owners forums on who could get their airplanes to spin. I had the airplane for 3 years and during that time I got it to spin only three times. It was work each time with the airplane just doing a normal stall. Each time, it was summer time (high density altitude), aft CG, and hard stomping on the rudder to get a spin out of it.

That is normal behavior for LE slats. They just won't spin depending on the CG location and conditions. That is why slats are used as an anti-spin device by engineers!

The Bf-109 exhibits the same normal behavior for LE Slats. It is difficult at best to get it to spin under normal operating conditions

[Crumpp]

I even tried spinning it - according tp the POH it was possible, but
despite several attempts I never managed a convincing spin which was
quite re-assuring!.

http://groups.yahoo.com/group/Rallye/message/2974

LE Slats equipped aircraft are very pedestrian in the stall / spin behavior department by design.

[taildraggernut]

Entering stalls/spins from a gentle deceleration in level flight is a very different affair from an accelerated stall.

[Crumpp]

Entering stalls/spins from a gentle deceleration in level flight is a very different affair from an accelerated stall.

The results of both coordinated and uncoordinated accelerated stall behavior are documented in the RAE report.

See:

4.4. Stalling Tests.

The Bf-109 exhibits typical LE slat equipped behaviors.

When the slots were fully open the aircraft could be turned quite steadily until very near the stall. If the stick was then pulled back a little more the aircraft suddenly shuddered, and either tended to come out of the turn or dropped its wing further, oscillating meanwhile in pitch and roll and rapidly losing height ; the aircraft immediately unstalled if the stick was eased forward. Even in a very tight turn the stall was quite gentle, with no tendency for the aircraft to suddenly flick over on to its back and spin.

When the Me.109 was following the Hurricane or Spitfire, it was found that our aircraft turned inside the Me.109 without difficulty when flown by determined pilots who were not afraid to pull their aircraft round hard in a tight turn. In a surprisingly large number of cases, however, the Me. 109 succeeded in keeping on the tail of the Spitfire or Hurricane during these turning tests, merely because our Pilots would not tighten up the turn suficiently from fear of stalling and spinning.

http://kurfurst.org/Tactical_trials/...ls/Morgan.html