Author Topic: HT, a Question about the Spit FM: (Read 2528 times)

Major Biggles · « **on:** February 07, 2007, 05:03:40 PM »

HT, i was wondering how you've modelled the spit death stall. is it something that should happen, is it a bug, is it an unfortunate flaw in the spitfire?

it just seems awfully unrealistic, especially in the spit1. the plane just sits perfectly inverted, engine off...

surely a plane doesn't do that, even if it has no engine to pull it forwards, wouldn't the stabilisers point the nose down?

could you describe why the spit, and only the spit does that deathstall, especially the mk1 and 5? it's always puzzled me, it doesn't seems real... if it is a bug in the FM, are you aware of it?

Krusty · « **Reply #1 on:** February 07, 2007, 06:21:33 PM »

The spit is not alone. P38s can get into perfect float-down stalls as well. Mossies have been known to have unrecoverable, no-oscilation, perfectly flat vertical descents (as well as perfectly-still arse-first tail slides), and the Ta152... my god the 152... *shudder*

Major Biggles · « **Reply #2 on:** February 07, 2007, 06:22:45 PM »

mossie is bad, but nowhere near as bad as the spit1, it's just not right, a plane doesn't do that in real life, it should point the nose down no matter what you do with the controls...

Krusty · « **Reply #3 on:** February 07, 2007, 06:29:55 PM »

Definitely agree, with several planes that have odd stalls.

Widewing · « **Reply #4 on:** February 07, 2007, 06:50:33 PM »

Well, the Spit16 is prone to flat spins, but if you have a few thousand feet under you, you can recover. In comparison, you can push the Spit8 much harder without departing into a flat spin.

Mossie, some Spits, Bf 110, and the P-38s all suffer from this problem.

My regards,

Widewing

Major Biggles · « **Reply #5 on:** February 07, 2007, 06:55:05 PM »

Quote

Originally posted by Widewing
Well, the Spit16 is prone to flat spins, but if you have a few thousand feet under you, you can recover. In comparison, you can push the Spit8 much harder without departing into a flat spin.

Mossie, some Spits, Bf 110, and the P-38s all suffer from this problem.

My regards,

Widewing

it's not the flat spin that i'm referring to WW. it's the inverted float that i think needs fixing, i's not realistic. the spit1 has no chace of getting out of it because the engine cuts when you flip upside down, so you have no power to bring yourself out. the plane shouldn't do this anyway, the stabs would push the nose of the plane towards the ground, just like a weather vane.

it's that inverted flat spin float, that is most obvious in the spit 1 and 5.

dtango · « **Reply #6 on:** February 07, 2007, 10:31:03 PM »

Quote

Originally posted by Major Biggles
...it's just not right, a plane doesn't do that in real life, it should point the nose down no matter what you do with the controls...

Might check your aerodynamics

. What do you think happens in a flat spin or better yet, inverted flat spin in real life - especially the kind you can't recover from that kills people in real life? And without film and based on your descriptions I'm assuming that's what's happening.

One of the big issues with flat spins is that the angle of attack is very high (worst case at 90 degrees) which means you no longer have air travelling along the chord-wise direction of the wing which means that your rudders and elevators and possibly ailerons are rendered useless because there's no air flowing over them in the direction that they were designed to be used for. That's what makes flat spins so dangerous because you can be stuck in state that you can't get your plane "flying" again.

Here's an example of a real inverted flat spin done albeit on purpose by an acrobatic pilot in a stunt plane who can recover from it:
http://www.bulldogairshows.com/video/1997promo/flatspin.avi

I've done my share of flat spins and inverted flat spins in P-51's in AH. About 80% of the time I'm unable to recover. Usually they involve me hangin just a bit too much in the vertical intentionally or unintentionally. Here's a recent film of one where I screwed up trying to get ready to perform a hammerhead (use the film viewer and watch it from the external or fixed views - better with trail turned on as well) - note that once in a flat spin my rotation actually slows down dramatically which makes it seem like I'm just floating down upside down.
http://brauncomustangs.org/films/film61_flat_inverted_spin.ahf

Here's some info on the net regarding flat spins that's enlightening. The discussion regarding badly executed hammerheads and the result seem to describe my flat spin in the AH film above.
http://www.flyingmag.com/article.asp?section_id=14&article_id=699&print_page=y

I'm not a real life pilot so don't know all the ways you might try and recover from a flat spin but from what I've read one way to do it technically is transition it back to a normal spin and then recover using usual techniques. The trick is if you're able to get out of the flat spin into a normal spin with your nose pointed down. One trick is to deflect aileron in the direction of the spin.

Tango, XO
412th FS Braunco Mustangs

1K3 · « **Reply #7 on:** February 07, 2007, 10:39:27 PM »

Yeah Spitfire may be manuverable but if you spin it it's hard to recover. 109 and 190s are not that manuverable but getting out of a spin is easier in 109/190 than spitfire.

OOZ662 · « **Reply #8 on:** February 07, 2007, 10:43:27 PM »

There is NO spin in what he's talking about. The aircraft doesn't rotate around any axis. Take a toy plane, hold it inverted and horizontal, then move your hand toward the ground. There you have a sped up version of what happens in Aces High with these aircraft.

BaldEagl · « **Reply #9 on:** February 07, 2007, 10:49:55 PM »

I think this might be the same phenomenon (excepted from a post of mine in another thread... I was in a Spit V):

I fly out and there's a mountain range between our bases. As I approach I spot a NIK at about 7K. OK, I'll go get the NIK first then I'll go get Axer. This is going to be great! I'm chasing the NIK around the mountains, close enough to get a few pings on him but never close enough to bring him down. Suddeny: Ping Ping Ping and my left wing is gone.

My plane rolls over inverted and I know it's going to go down fast. I want every opportunity for the pings I landed on the NIK to become a kill for me and I can see friendly dots approaching so I shut off the engine.

Here's the strange part:

My plane floats gently toward the ground inverted at about the same speed as a chute. As I float there I watch the friendlies come in, engage the enemys, planes are flying all around me until the battle ends and everyone flys off and I'm just floating there upside down taking it all in.

DREDIOCK · « **Reply #10 on:** February 07, 2007, 11:41:26 PM »

Quote

Originally posted by 1K3
Yeah Spitfire may be manuverable but if you spin it it's hard to recover. 109 and 190s are not that manuverable but getting out of a spin is easier in 109/190 than spitfire.

I have never gone into a flat spin or an unrecoverable stall in either a 109 or a 190.

110's yes, a pony, Yes, a mossie Yes
but never a 109 or 190

---EDIT---

At least not without having an important part of my plane shot off first LOL

dtango · « **Reply #11 on:** February 08, 2007, 12:19:32 AM »

Quote

Originally posted by OOZ662
There is NO spin in what he's talking about. The aircraft doesn't rotate around any axis. Take a toy plane, hold it inverted and horizontal, then move your hand toward the ground. There you have a sped up version of what happens in Aces High with these aircraft.

If that's the case then give HTC the film. They're more than happy to look things over.

More than likely the aircraft transitioned from some form of flat spin to flat stall (where there is zero rotation around the yaw axis). Spins occur because the left and right wings of the aircraft are producing different lift in a stall because the variation of angle of attack between the left and right wings for a variety of reasons. As you near 90 angle of attack on both wings in a flat spin/stall it's conceivable that any spin is arrested by the natural directional (yaw) stability of the aircraft resulting in just a flat stall with little to no rotation around the directional (yaw) axis of the aircraft.

If you can't get your airplane out of this attitude, what you end up with is the airplane pancacking into the ground spin or no spin.

Tango, XO
412th FS Braunco Mustangs

MajWoody · « **Reply #12 on:** February 08, 2007, 12:28:16 AM »

I used to have some bad ones in the KI84 that were unrecoverable. I sometimes held it in the vert too long & then floated down tail first. Shutting the throttle or the motor down had no effect. All the way down from 10k slowly, tail first. Very unrealistic. The weight of the engine should cause the nose to drop off like a lawn dart.

Karnak · « **Reply #13 on:** February 08, 2007, 12:34:43 AM »

Quote

Originally posted by 1K3
Yeah Spitfire may be manuverable but if you spin it it's hard to recover. 109 and 190s are not that manuverable but getting out of a spin is easier in 109/190 than spitfire.

Which would not be historically accurate.

The Spitfire Mk XIV (the massively over torqued one) had to be held in a spin or it would recover on its own after two or three rotations. Thus said Jeffery Quill, the Spitfire program's chief test pilot.

Widewing · « **Reply #14 on:** February 08, 2007, 12:35:21 AM »

Quote

Originally posted by dtango
If that's the case then give HTC the film. They're more than happy to look things over.

More than likely the aircraft transitioned from some form of flat spin to flat stall (where there is zero rotation around the yaw axis). Spins occur because the left and right wings of the aircraft are producing different lift in a stall because the variation of angle of attack between the left and right wings for a variety of reasons. As you near 90 angle of attack on both wings in a flat spin/stall it's conceivable that any spin is arrested by the natural directional (yaw) stability of the aircraft resulting in just a flat stall with little to no rotation around the directional (yaw) axis of the aircraft.

If you can't get your airplane out of this attitude, what you end up with is the airplane pancacking into the ground spin or no spin.

Tango, XO
412th FS Braunco Mustangs

Different aircraft display different behavior.... I've linked to a film I made of the Mossie, Spitfire MkI and the Bf 110G-2. When viewing the film, do so from the fixed view with trails turned on.

Strange Stalls

My regards,

Widewing