Number 1 Spitfire Inverted Flat Spin Recovery

[nrshida]

After flying the Number One Spitfire in the MA recently a discussion began about the stall characteristics and especially the inverted flat spin, which has the additional fun feature of cutting the engine due to the lack of gravity (which the carburettors need to feed fuel with this type).

I suggested to RTHolmes that you can escape by Elvis Presleying your way out of it, Rock and Rolling in other words 

Unfortunately the film viewer doesn't seem to depict the control surface movements but what I try to do is to get the plane to rock at the same time as oscillating the ailerons and looking for suggestion that the nose is ready to come back down.. Sometimes this works quite quickly. I have a feeling that the effect of the elevators is reversed in this position, so you often need to push slightly forward on the stick at the right moment. About ⅓ I suggest. Once the nose does start to go slightly downwards again it is important to be gentle or the spin will restart again very quickly. Once it has settled down you can restart the engine with the starter and go about your business.

Naturally this costs some altitude!


Number 1 Spitfire Recovery 2.ahf

[olds442]

also i thought more than just the spit in the hurricane had float carbs i know some planes where throttle linked carbs and some where fuel injected (db605) but i think the early allisons had float carbs then went to throtle carbs. all in all i know the d7 had a float carb so if you go negitive in it heck in most ww1 planes it will stall.

[Krusty]

Not all float carbs cut out in negative G. It was an issue with the gas feed in those Merlin engines specifically. The Spit Mk.XII had a similar issue at first and pilots were quite upset. They were told the cutout was a thing of the past and yet were still experiencing it. A rep from the factory came out (a lady on a bicycle the story goes) and replaced a rubber diaphram in all the engines' carbs and the problems disappeared.

I don't know if Allisons had that float carb or not, but regardless they did not have the negative G cutout.

[RTHolmes]

I can usually catch those given some alt, I was talking about the full tailslide. took me quite a few attempts to replicate it offline (25% fuel helps apparently) and now my ISPs hosting server is down  happens to me when i'm pulling inside a turn for a shot almost vertically so pull up get to ?70mph and push forward. if you catch it while you still have forward motion and some controls you're good, once you start tailsliding properly nothing much seems to help.


edit: here we go http://www.lumbergh.aquiss.com/ah/ah_films/tailslide.ahf

[nrshida]

I see the problem RTHolmes, will have a bash at this one this afternoon.

I read a bit further, it was a flooding problem apparently, which Tilly Shilling fixed with her little orifice 

She was quite a character I think:-

http://en.wikipedia.org/wiki/Beatrice_Shilling

[Tilt]

According to anecdote, she refused to marry him until he also had been awarded the Brooklands Gold Star for lapping the circuit at over 100 mph.

My kinda girl!!!!!

[olds442]

Not all float carbs cut out in negative G. It was an issue with the gas feed in those Merlin engines specifically. The Spit Mk.XII had a similar issue at first and pilots were quite upset. They were told the cutout was a thing of the past and yet were still experiencing it. A rep from the factory came out (a lady on a bicycle the story goes) and replaced a rubber diaphram in all the engines' carbs and the problems disappeared.

I don't know if Allisons had that float carb or not, but regardless they did not have the negative G cutout.

in any case a float carb will cut gas un neg G's so the planes with them should lose power when in neg G's because it will cut the gas so much the engine will lean its self out giving the engine a high rpm then a stall.

[MiloMorai]

Not all float carbs cut out in negative G. It was an issue with the gas feed in those Merlin engines specifically. The Spit Mk.XII had a similar issue at first and pilots were quite upset. They were told the cutout was a thing of the past and yet were still experiencing it. A rep from the factory came out (a lady on a bicycle the story goes) and replaced a rubber diaphram in all the engines' carbs and the problems disappeared.

I don't know if Allisons had that float carb or not, but regardless they did not have the negative G cutout.

Yes they will! The lady was a Beatrice 'Tilly' Shilling and the fixed was named Miss Tilley's Orfice. Miss Shilling with a small team travelled around the countryside in early 1941 fitting the restrictors, giving priority to front-line units.

[morfiend]

in any case a float carb will cut gas un neg G's so the planes with them should lose power when in neg G's because it will cut the gas so much the engine will lean its self out giving the engine a high rpm then a stall.

 Actually you have this backwards,the float bowls don't get fuel because the floats are at their highest point so the carb doesn't demand fuel from the system.What fuel is in the carb gets used up and the engine is fuel starved and cuts out.

  It doesn't run lean,that would be a mixture setting and has nothing to do with what happens under neg.G's


  1 of the biggest issues with the flat spin/inverted spin in the spitMk1 is caused by combat trim!  Once the plane enters at stall CT dials in full up elevator,much like in the TA152 and this causes you to have problems getting enough down elevator to pitch the nose down.

 Turning off CT and giving full down elevator trim can help alot,so can lowering the gear! If you lowered flaps you've made the situation worse,this also dials in full up elevator trim and can make recovery all but impossible.


   YMMV!


   

[olds442]

 Actually you have this backwards,the float bowls don't get fuel because the floats are at their highest point so the carb doesn't demand fuel from the system.What fuel is in the carb gets used up and the engine is fuel starved and cuts out.

  It doesn't run lean,that would be a mixture setting and has nothing to do with what happens under neg.G's


  1 of the biggest issues with the flat spin/inverted spin in the spitMk1 is caused by combat trim!  Once the plane enters at stall CT dials in full up elevator,much like in the TA152 and this causes you to have problems getting enough down elevator to pitch the nose down.

 Turning off CT and giving full down elevator trim can help alot,so can lowering the gear! If you lowered flaps you've made the situation worse,this also dials in full up elevator trim and can make recovery all but impossible.


   YMMV!


  

in neg g's the float goes up making the gas cut out. thats exactly what i said
and it will run lean. to much air and to little gas= lean.  when your float goes up in neg G's that engine gets fuel starved BUT not air starved. that means lean.

[DMVIAGRA]

RAF after realising how clumsy the Spitfire was.

[morfiend]

in neg g's the float goes up making the gas cut out. thats exactly what i said
and it will run lean. to much air and to little gas= lean.  when your float goes up in neg G's that engine gets fuel starved BUT not air starved. that means lean.

  Ok.....    when the float bowls are empty the engine runs lean,oh and increases rpm.

  So if you shut off fuel flow will the engine also run lean? After all it will still get air just no fuel so as you explain it it must run lean.




   

 PS: I suppose you'll tell me the fixed it with fuel injection.

[RTHolmes]

looks like I'm not the only one that cant recover the spit I tailslide o death 

[Oldman731]

looks like I'm not the only one that cant recover the spit I tailslide o death 

Take comfort.  I have never been able to recover from it, and I believe I have tried all the solutions proffered in this thread.

The moral is not to get slow at the top of the loop. 

- oldman

[olds442]

  Ok.....    when the float bowls are empty the engine runs lean,oh and increases rpm.

  So if you shut off fuel flow will the engine also run lean? After all it will still get air just no fuel so as you explain it it must run lean.




   

 PS: I suppose you'll tell me the fixed it with fuel injection.

lets do this 5=hgihest 0=lowest

so at first lets do a unrealistic 3 gas to 3 air
now you go negative g's the gas goes to 1 and air goes to 3 this is lean and engine is still running
now your upside down and this is what happens 0 gas to 3 air now this is not lean because the engine sshut off.