hoooooolllllyyyyyyyy s**t......

[DeltaTango]

It had been a long and satisfying flight.
Beautifull weather, and not so much traffic to report. We were comming back from a 2.5 hour flight which was devoted to a radio stations listenners on a need to know basis about the various traffic jams up and down the coast.

It was the last of 2 trips I had to join, in order to be scheduled to fly the highly complex sortie with the mission of reporting traffic jams.

Anyway, 10 miles out from home, the pilot suddenly started to tighten his harness and make some safety turns after which he turned and asked:
"How do you feel about spins?''

I quickly tightened myself as best as I could to the seat and replied very calmly:
"F....f.....find w...with me......"

So he went on to a couple of half spins, I remark this since they looked nothing like any stalls I have ever performed, and we turned for home.

My doubts about the maneouver has opened new questions, one of which are: What exactly happenes during a spin???!?!?

Please fill in the missing bits this clouse:
One wing stalls and then_____________because_____________and the result is_________________.


Thank you
DT

[willbav8r]

Erm, I think you'll find BOTH wings are stalled.....

[mad_jock]

Depends what tye of plane you are in. But both wingsare always stalled.

Some are more docile than others. A cessna C152 has to be worked to keep it in and will usuall recover itself without the shove forward the POH recommends. Now the PA38 with half tanks on board will be a different kettle of fish. The rotation will be 3-4 times faster than the cessna and you will loose vast amounts of height very quickly. But if you follow the POH it does come out at the bottom. Typically for a 3000ft height loss it will be 3-4 rotations depending how much fuel you have on board in about 15 seconds. It also sounds scary as hell because of the stalled wings there are huge vortexs shedding off the wing which because it has a high T bounce off it causing the whole thing to shake, the control runs up the tail bang off the skin and cause a hell of a racket. Which when combined with the wing drop cause people to call it a Terrorhawk. Personally I luved instructing in them and a student who learn in a tommy found cross training onto other types a breeze.

MJ

[B2N2]

Check out this link http://www.av8n.com/how/#contents
item #18 deals with spins but lots of good info on this one...
Have fun..

[Thumpango]

Mad_Jock,

there are lots of stories about PA38 spins, but just how badly do you need to treat a traumahawk before it gets upset and bites?

I really like the PA38 and have grown to love it but this area does worry me a little - well, more than a little actually!

[mad_jock]

The CAA made them put strips on the leading edge which gives you buffet now so the stall isn't quite as instant as it used to be.

Basically if you don't control the wing drop on the stall it will flick you into a fully developed spin. But it will come out again by its self. But it happens that fast its very likely that you will go through Vne.

I have managed to get it to flick through into a spin using roll to correct wing drop. But it requirers such a hurrendous attitude I don't think your average PPL would even come close to getting it into that part of the envelope.

The reason why most FI's don't like Spinning the tomahawk is that most FI training is done on a C152 or the like which dosn't really spin properly and you have to work to get it into a fully developed spin. The tommahawk is much faster and if they don't know about carrying low fuel will come as a bit of a shock.

It also takes a while to be able to patter the spin properly. You usually have to do a couple first with the student before pattering it because of the amount of swearing coming from the LHS.

MJ

[B2N2]

Have been at least 12 fatal stall/spin accidents in Traumahawks.
Most of them on skill tests/checkrides with experienced pilots/examiners usually for initial FI rides.
One examiner managed to recover at very low altitude and told a horrible story of the yoke being stuck in the full back position.
They later figured out it was a design error in the yoke/panel configuration.(AD issued)
Also the Pa38 was designed to be assembled by an unskilled labour force (to keep prod. cost down) and the prototypes used for certification had additional strengthening in the aft fuselage and wings that was omitted in the production versions.
There's a rumour that the Piper Chief designer at that time sent a memo to Piper HQ to recall all Pa38's and shred em.
You'll never see me flying one..imo it's a low wing T-tail 152, so they got everything wrong...lol

[wobblyprop]

I learnt in a tomahawk and remember the instructor saying there was an AD to strengthen the tail if you intentionally wanted to go spinning it. Presumably a 4 point harness would be nice, too.

tomahawk scared the life out of me the first time i stalled it.

[mad_jock]

I think most have the tail mod now for the cracking problem.

Also its manditory to have 4 point harness if you spin them.

I believe a student managed to lodge themselves forward across the instructors lap which must have been fun at the time.

They are a good trainer, plenty of room, instructor can get at the fuel selector easly. Quite responsive, huge rudder.

Worst thing about them is that awful trimmer.

MJ

[BigEndBob]

When demonstarting the effect of rudder the Tomahawk pitches down before any significant yaw sets in.....very strange.
The Tomahawk always seemed like a nice aeroplane missing a wide chord wing and low tail.
Flying clubs love them because they are cheap ....and so are Ladas.
These days i bet there are very few Tomies that haven,t had their front end rebuilt!

[mad_jock]

When demonstarting the effect of rudder the Tomahawk pitches down before any significant yaw sets in

I think it could be because it has such a large rudder. When you put the rudder in there is a increase in drag which causes the pitch change.

The only other thing i can think of is the trimmer being that daft spring tension device, its not actually a proper trimmer. By altering the airflow round the back end you don't get enough tension on it.

I must admit i have to make a mental note about side slipping when flying a PA28 after the PA38.

MJ

[Send Clowns]

Second best advice I heard about the PA-38 was "never look at the tail if you're spinning the Tomahawk" (given by a man who had been an instructor for 50 years). Best advice was "never fly a Tomahawk". I took both :p

A description of a spin really relies on a demonstration with an aircraft model. In essence it is a "flight" condition with wings stalled and yaw. In a developed spin there is yaw, roll (in the same direction as yaw for an erect spin) and pitch at the same time. In many aircraft these combine to a stable motion about an axis close to one wing tip combined with rapid height loss (I seem to remember up to 11,000 feet per minute quoted for the Bulldog, though I may be mistaken). Other aircraft such as the Cessna 152 never really become stable and "nod" through the spin, which I find more uncomfortable although these recover more easily. The unstable spin and easy recovery are connected.

[Keygrip]

Interesting reading - the history of the terrorhawk - used to fly 'em out of Manchester and agree with all the tail wagging stories. Scared the c**p out of me during the instructor course - I don't believe the tail of any aircraft was ever designed to do what I saw it doing whilst spinning.

What I've been curious about (since reading the first post on this thread) is why was an aircraft - on what would appear to be a public transport flight, carrying a passenger - spinning?

[mad_jock]

Its better it flexs than it dosn't. Stiff tail equals high stress.

Well looking at the posters country I would have though that spinning wasn't half as dangerous as driving home afterwards.

Some instructors love them some hate them. I always liked them. Plenty of room proberly being honest being the main factor. Linked with low wing for teaching circuits and a sprung steel gear which as long as you keep the nose wheel out of the way the student can drop onto from 10ft with only there pride damaged.

Yes they are cheap, if the instructor enjoys teaching in them. If the instructor doesn't like them its a bit unfair on the student because the instructor will tend to get a bit snatchy with the controls at any sign of low airspeed. I have had a few inherited students from an instructor like this and discovered that the instructor had refused to do a full clean stall due to them ****ing themselves the first time they tried one. And had installed fear into the student about the handling aspects (the student though a 35-40 deg turn was steep)

MJ

[Finals19]

Here's a bit on the PA38 I managed to read up on:

.....the original PA38 prototype was markedly different from the production model - it had eleven ribs per wing (therefore a stiff wing) and a vertical tail offset by 2.5deg, and also the engine thrust line offset. The final test report gave this build the thumbs up as a excellent training aircraft. Piper observed that a prerequisite for this was that the wing used had to be stiff (GAW1 type wing). However when the production model came out, all but four of the wing ribs were removed, and there was no off set tail fin or engine thrust line.

The more flexible wing initially caused nasty stall characteristics and snap spin characteristics. Even after stall strips were added things only improved to a point.

There is also an apparent issue with W&B limitations. Near MTOW there is a possible issue with aft out of limits c of g when the seats are shifted to there rearmost points.......

I think I will stick to 152's which are very easy to spin and even easier to recover....

[Send Clowns]

It's better it flexs than it doesn't. Stiff tail equals high stressThe problem comes with metal fatigue and with breaking strains! Also with confidence. On a more serious note the aerodynamics of any surface can be altered by its movement. You must know about control reversal with wing deformation. Not sure what would happen in a spin with the tail waving all over the place!

[mad_jock]

H'mm breaking strains no aeroplane operates materials inside the plastic area of the stress strain curve to my knowledge.

Strain is related to stress via youngs moduli in the linear region of the stress strian curve so a breaking strain is really a buckshee punters way of defining breaking stress which again is a buckshee term. You have Yield Stress where the metal goes plastic and deforms, Ultimate Stress (sometimes is less than Yield stress but huge plastic strains have occured) when the whole lot fails and metal departs from each other under a plastic (ductile) failure, and Critical crack intensity when there is a crack and the whole lot goes with a bang.

In relation to the S-N curve for fatigue its highly non linear at the high stress levels. As the stress levels decrease the number of cycles before fatigue increases by factors of 10 quite quickly. From memory at 75% of Yield stress you can get 1e4 cycles out of steel and at 25% 1e8.

There for if you make the tail stiff there is high stress so fatigue becomes a problem along with critcal crack intensity which was why they stuck the plates in the tail to stop the cracking problem. But this wasn't to stop the flexing in the tortional sense which everyone can see and dosn't like. It was at the root of the tail where the control runs go up the front of the tail Flexible tail means low stress so fatigue is not a factor.

The only thing which isn't stalled is the rudder hence it is the only control that works. This can be seen if you spin an aircraft and while recovering shove the nose forward. When the tail starts flying again you will get a nasty neg G bunt and other nasty complications that the test pilots won't even try. So until you come out of the spin the controls apart from the rudder arn't effective so can't be reversed and after the spin the wings are unstalled so no more vortex buffet so no more flexing.

MJ

[Send Clowns]

But over time with a metal fin the breaking strain reduces, due to metal fatigue. I did indicate that this was not entirely serious, although it is not confidance-inducing. However if the fin twists then the rudder must become less effective, even if it does not go far enough to reverse.

[mad_jock]

What do you mean by strain? Strain is defined by change in length divided by the original length. (delta)L/L

The tail flexs in torsion, the top appears to move alot, but does it?

Yes it will move a little but what people actually see it the ends of the elevators deflecting up and down which are moving up and down by less than 10cms which I suspect is acutally very little movement in torsion on the actual emphange which is the bit thats doing the twisting. Its the arm away from the emphange which causes what appears to be large movement. Which when combined with the high T's inertial being so far away from the center of rotation makes for what looks like large deflections.

As soon as the rudder is put under load to correct the spin the whole lot will stop due to the load being more than the load being applied by the vortexs. This load will be factors in magnitude above that being created by the vortexs. And it will be the same as if the plane was a low T. The amount of twist that occurs will again be the same as the low T so control reversal of the rudder will be just as unlikely as in any other part of the flight envelope or any other type.

So with out doing any calcs on it I would reckon the actual maximum stress created by the torsional twisting of the tail in the spin is proberly just past the static port on the emphange. The place where it occurs is dependant on the section taper of the emphange. And is proberly lower than in a side slip.

And to note you cannot tell anything about the fatigue state of a structure by just looking at a displacement. Its the stress level which this deflection induces when analysed in comparision to a S-N (which stands for Stress-Number of cycles) material curve. Linked in with the history for that bit of metal. 1 tail scrape would take years off the life of the structure compared to spinning once a day everyday of the aircrafts life.

MJ

[Send Clowns]

Jock

Since there is no overall stretching in this case strain is the amount of movement. This still allows the concept of a breaking strain, which will reduce with fatigue.

In case you hadn't noticed (such as the hint that I said it directly) the comments on the tail actually breaking were not intended to be taken especially seriously. One is forced in aviation to trust the people who certify an aircraft that it will not fall apart. The point about the tail moving so much in that area is one of confidance - it does not increase with large movements. I also did not say anything could be told about fatigue life by movement. What I said was that fatigue can be caused by repeated movement well below the initial breaking strain, which it can. You only have to twist a paperclip to prove it. A tailscrape will of course make no difference to the fin, although it will cause damage in the tail boom.

More seriously if you are suggesting that the loads twisting the tail are much less than the normal loads imposed by control inputs As soon as the rudder is put under load to correct the spin the whole lot will stop due to the load being more than the load being applied by the vortexs [sic] then I would suggest that the twisting under the (greater) loads caused by the rudder displacement will be greater. Of course control reversal is caused not by cyclic flexing but by the twisting caused by control deflection.

[mad_jock]

Since there is no overall stretching in this case strain is the amount of movement. This still allows the concept of a breaking strain, which will reduce with fatigue.

Of course there is over all stretching. If there wasn't any stretching there wouldn't be any stress so no fatigue would occur and for that matter the structure wouldn't be under load.

The paper clip failing is because you have loaded the metal up past its Yield stress into plastic deformation hence high strains and work hardening which as I stated early put you at the very top of the S-N curve ie 100% stress which put you into the area of very low cycles to failure. Which i might add is a completly different mode of failure to the high cycle fatigue which is due to cracks migrating until the critcal crack intensity is reached. But the load that is able to be supported is the same until very late on in the fatigue life.

But you still don't seem to grasp that structures do not fail due to strain they fail due to stress. Which is defined as the load in newtons divided by the area it is applied over.

Yes I am saying the forces on the tail are alot less due to vortexs coming off the wing. They are applied on a lever and not as a constant force which is why it flutters (technical term is bluff body dynamics). As the air speed increase it is on the squared law so if side slipping double the speed 4 times the load at full rudder 3 times 9 etc. Its effects of controls part 1 fast firm controls slow sloppy controls etc.

The reason why I take exception is there is so much bollocks talked about tail flutter with persudo engineering talk used as justification. And if people believe this bollocks a prefectly good training aircraft will continue to have a crap reputation due to FI's who don't know any better continuing the bollocks.


MJ

[Send Clowns]

Actually the reason I wouldn't spin a Tomahawk is that it has a T tail. As I said, I was being light-hearted, never intended to suggest that the tail would actually fail, with my comments really refering to confidence. I personally would assume it would come out of a spin, but I see no reason to spin an aircraft which is specifically designed with poor stall-recovery characteristics.

Your comments explain why the tail flutters - well it is accepted that it does and I understand flutter, but my point was not that the flutter has any control effect at all. Control reversal (or at a lesser severity reduction of control effectiveness) occurs due to twisting caused by the aerodynamic forces from the control, not from flutter.

[mad_jock]

Go on then I am going to bite.

Please explain why a High T light aircraft is any harder to unstall than a low T aircraft? Or for that matter why it is any nastier to stall than a Low T. The tommahawk is actually harder for the student to put into the stall than the cessnas. The fact they actually have to fly it properly thus training them properly is neither here nor there.

You may say jokingly that you don't mean that the tail will fail. But there are numerous FI's out there who use exactly the same arguments that you have used as a reason to not fly them or stall them. Spinning is a personal thing if your no comfy with an aircrafts handeling don't do it. But all FI's should be able to do a clean stall in any training aircraft.

but I see no reason to spin an aircraft which is specifically designed with poor stall-recovery characteristics.

I don't really see the reason to spin any aircraft to be honest. But if you let go of the controls in the stall it recovers all by its self, if you push the nose forward it recovers, if you put the power up it recovers. Whats poor about that?

Spinning once in the spin if you neutralise the controls select min power and apply opp rudder it comes out after a turn. So whats poor about it?

I agree about control reversal but in the tail fin its way to stiff especially in the Piper and cessna configurations for rudder reversal to occur.

All you are doing is promoting the bollocks that is spoken about the tommahawk. Your trying to justify to yourself that its dangerous when it isn't any more dangerous than spinning any other aircraft within the limits specified in the POH.

MJ

[BigEndBob]

I,m going back a bit now, from memory i seem to remember that the spin itself wasn't much of a problem re; breaking tails, but the very steep nose down attitude and clean design allowing very rapid increase in speed, which could panic the pilot into too rapid a pull up and breaking something.

Got to admit the Tomahawk is the only aircraft ive been in and seen my life pass before me. Always make sure you read the ( i seem to remember) 3 pages on how to spin the tomahawk in the flight manual.

[mad_jock]

BigEndBob that is a more than fair comment.

And Iwould always recommend reading the POH for what you are actually meant to do instead of relying on word of mouth from other FI's.

MJ

[Send Clowns]

M_J

The T tailplane sits in disturbed air from the mainplane in a stall. This means that the elevator has less authority (that should certainly have been taught on your principles of flight course). It may also be the reason that the aircraft is difficult to stall, as the loss of authority may be coming in early.

All light aircraft can be recovered from a spin in the standard configuration, it is part of the proving of the aircraft. However there can be other factors, such as fuel imbalance, that can make the spin recovery significantly more difficult. Although I see good reason to spin for training purposes, I see no reason to do so in a T-tailed aircraft.

[mad_jock]

It may loose as a small amount of authority due to the turbulence from the vortexs. But the main factor is it dosn't benifit from prop wash. Which is a more marked effect, giving the student less authority putting the plane into a stall at low power due to reduced air flow over the back end. Recovering from the stall is as quick and responsive (if not better) as any other training aircraft in my experence using the standard techniques. Which is 300 hours on 150's 152's 172's and 700hrs on PA38's and 100hrs on PA28's. And come to think of it 6 hrs in a seminole which has very similar stall handling as the PA38 from what I can remember and 49hrs in a Cougar which stalls like the PA28.

And to be honest as the elevator has nothing to do with the stall recovery in a spin its not really a factor in this dicussion. As posted previously when you correct the spin the biggest worry is busting Vne.

And as for the ATPL principles of flight course, which i don't think i have deviated from yet. I think I will stick to the principles of flight I used to teach to under graduates on there degree courses backed up by the basic priciples of structural engineering and fluid dynamics. Along with running labs in the wind tunnels with the spotty perverts for 2 years.

Before you start about super stalls on large high T aircraft yes I know about them. We are talking about only a SEP training aircraft.

You are just showing how the bollocks about the PA38 is so popular and unfortunatly believed by many.

MJ

[snooky]

I remember spinning an early tomahawk (before the stall strips were added) and finding it very exciting.
After the first fatal accidents a CAA test pilot came up with a document describing several different spins possible in the type, with different recovery recommendations for each.

The hinges on the rudder, I remember, had lots of washers used as spacers. If the wrong number of washers were present, with full rudder and full up elevator the controls could jam against each other in the tail!

[QFTJT]

After reading some of the assumptions that certain individuals have posted on this forum I think it is a good idea that you stay away from Tomahawks. I’ve actually been quite amused by the comment made by the so called “Tomahawk expert” on this forum

People here either like the aircraft or hate it. If you don't like the T- tail, the way it spins or its "poorly or flimsy tail" and design characteristics, that's fine. Nobody is forcing you to fly one. But don't post absurd assumptions about this aircraft, when:

1. You have never flown one
2. You have no technical knowledge of the aircraft
3. Have limited total aviation experience and knowledge
and
4. You have never consulted the POH or even spoken to any highly experienced PA-38 owners or pilots.

mad_jock

The Tomahawk WILL NOT come out of an incipient spin unassisted. You said that you would “get it to flick through into a spin using roll to correct wing drop” and “it requires such a horrendous attitude I don't think your average PPL would even come close to getting it into that part of the envelope”. Then what have been the main reasons SPL PPL and CPL holders have not been able to recover from spins, resulting in fatal accidents? I wonder what was the reason was that they were unable to recover? You also stated” the elevator has nothing to do with the stall recovery in a spin“ that is ridiculous.

I’m not sure how “altering the airflow round the back end” would cause the trim springs to not provide enough tension, maybe you could elaborate? Just out of interest, when was the last time the trim springs were changed in the aircraft it question?

Regards,
QFTJT
International Piper Tomahawk Club

[mad_jock]

I wouldn't say I am an expert by any stretch.

I quite agree that once your in a fully developed spin its either recovery action or hit the ground.

The comment was mainly for if the student doesn't catch the wing drop and releases everything the plane will accelerate and take its self out usually with a fairly steep nose drop but you are correct its not a cert.

As for the problems. In the uk there are some fairly stricked rules about spinning them.

1. 4 point harness
2. No more than half tanks, the more fuel the faster it rotates.
3. Entry is right back to full stall then gently let the wing drop into the spin without huge amounts of rudder input.
4. And no more than 3 rotations I think.

As someone else has posted its about 3 pages in the POH.

And as with all flight tests pre cert they can't cover all modes of spinning. The usual method of teaching spin entry in the UK in C152 etc is to flick them in with rudder input (and some keep the rudder input on until it really gets going). Which is against what the POH says for the tommy. Which I might add doing a reverse flick into the spin is definatly not allowed in the POH on purpose.

Also local conditions may be different to what the aircraft was tested in.

Which all leads the plane getting into a mode of spinning which was never tested. This isn't just the problem of PA38's. There have been plenty of cases with other aircraft where the Pilot has had to use techniques outside the standard eg increasing power to get more air over the rudder. In fact my FIC instructor managed to get into one of these modes with a C152 which it wouldn't recover with full rudder input and increased the power which forunately recovered it.

I can't and won't presume what happen in the incidents but I should imagine bits of the above will apply. And due to the high rotation rate and height loss compared to some types you have alot less time to play with it to get it to recover. To much fuel in is really scary about 1" below the cross is my max.

Elevator in the spin. During a fully developed spin the only effective control is rudder. Yes I know you can roll in the tomahawk and it will go from nose down to flat and back again. (NOT recommend again its not in the POH). The only time the elevator becomes effective again and unstalls, is when the spin is recovered using rudder and the plane starts flying again. This can be seen if the student has some forward input on the control the plane will neg G bunt into an even steeper nose down attitude (which is why i think its stalled). The elevator comes in when you have to recover the nose down attitude before the wings come off through busting Vne which was why there was the cracking problem at the fin root with people hauling it back. It may be a feature of the High T that the elevator is stalled in the spin due to lack of prop wash, but i havn't stuck any string on the back end to see if it is.

Trim springs as you know its proberly one of the worst features of the machine. I was only making a educated guess as to why the plane pitches when teaching yaw. I must admit the 2 I instructed in had new springs and I didn't notice any pitch change. You could be right, its a feature of old tired springs.

MJ

[Oktas8]

Elevator in the spin. During a fully developed spin the only effective control is rudder. ... The only time the elevator becomes effective again and unstalls, is when the spin is recovered using rudder and the plane starts flying again.

Now, one of us is misunderstanding something quite important, and I hope it's not me! :)

If one maintains nose up elevator in a spin, how will the wings become unstalled? And if the wings remain stalled, how will autorotation cease? I think the elevator is effective in a spin, but less than normal due to high angle of attack and high slip angle at the aft end of the fuselage. So by itself it will not necessarily effect a spin recovery.

With the exception of the Robin 2160, I don't know of a GA manufacturer-recommended spin recovery that does not involve elevator use to assist spin recovery. Note I'm talking about fully developed spins here.

The only time AFAIK that the elevator is completely ineffective is in a truly flat spin, at 90° angle of attack. Parachute time!

Having said that, thanks for taking the time on stress/strain explanations - very informative.

cheers,
Oktas8

[Mylo]

Here at goodwood,we spin the Tomahawk on a regular basis,and provided you recover as per the POH then the A/c will behave exactly as any other.
It is also a fantastic A/C for stall training,as it stalls properly therefore making the student more aware of this maneuver and the correct recovery techniques, unlike the PA28 that we also have and in which the stall can be a complete non event thus making it not the best platform for teaching stalling on.
And to those of you who have "been told by somebody" to avoid the PA38...(Clown in particular)....I suggest you try it for yourself before passing on negative information you have on an A/C you haven't even flown.......

[expedite_climb]

I believe a student managed to lodge themselves forward across the instructors lap which must have been fun at the time. Yup,
Spin left if the student is female, spin right if not.....

[mad_jock]

All the recovery procedures that I have seen require you to neutralise the controls, power to idle then apply opp rudder to direction of spin in there most basic form. While in the fully developed spin you can wiggle the yoke as much as you like and it won't recover the plane. It will have some other effects, but it won't get you out of it. This is only talking about normal spins which a PPL instructor would teach.

Some types recommend a bunt forward on the controls (Cessna I think says a firm shove forward which I have yet needed to do) after rotation has stopped. The wings don't unstall until after the rotation stops at which point you are usually pointing at a fairly steep angle towards the ground and you will accelerate very quickly towards Vne the last thing most people think about is shoving the nose forward. They are much more likely to pull it back hard with the possibility of stalling again or bending something. Instead of the smooth control input to level the aircraft before busting Vne.

Another common mistake on early spin lessons is for the student to leave full rudder applied after the rotation has stopped which can cause a bit of fun.

MJ

[Oktas8]

Ok I'll bite that hook mad_jock!

I agree with your comments, except with reservations for elevator use. You're describing a Muller-Beggs recovery, also recommended by some manufacturers as you said. However, Neil Williams, Szurovy & Goulian, this author (http://www.ozaeros.com/spin/beard.htm) and the FAA (http://www.safetydata.com/manual/61-67b.htm) point out that in many aircraft a positive check forward may be needed on occasion. IMO it is sending altogether the wrong message to pilots, to say that the elevator does not play an effective role in spin recovery. It may not, it will not in some aircraft most of the time.

The brisk forward movement (aft if inverted) of the control column occurs before spin recovery not after - no point at all if the aircraft has already stopped rotating. I had an aerobatically rated student once who was not checking forward in the A152, but relying on recovery on rudder alone. I entered a spin with partial power (as for a power-on stall), and closed the throttle after two rotations - the aircraft would not recover without a check forward, which surprised the student very greatly. Naturally, one will need to ease out of the ensuing dive fairly briskly, but that is the case for many spins. Most piston engined aircraft will not get anywhere near VNE unless power is on or forward pressure is maintained.

I realise mad_jock you qualified your post as referring to spins taught by a PPL instructor. In this country we do not distinguish between different types of instructor this way, so this discussion may be getting more advanced that you intended.

Anyhoo, cheers, O8

[mad_jock]

It may not, it will not in some aircraft most of the time.

I will bow to your experence, I am not an aero instructor and was only commenting on the training aircraft I have flown within the limitations of the normal spins PPL instructors teach. To be honest the only aircraft I have spun with any regularity is the tommahawk. Which I do with the utmost respect and feel comfy doing within the limits placed by the POH and my own limitations which is less fuel than the POH maximum.

I agree I was intending to discuss C152 and PA38's and other training aircraft which are commonly used at flying schools.

Must admit I have quite enjoyed thinking about the engineering side of things with the tommy. And I can see a wee trip with string taped under the leading edge and left over the top to see if the elevator is stalled in the spin with the tommy. And maybe some strain wax on the empange to see where the max stress occurs.

To be honest I was a structural engineer who was forced into doing fluid dynamics for thermo problems and wind loads on structures. Navier Stokes always drove me to drink and I could never be bothered waiting the 6 days it took to get the computer to spit out a CFD solution (and the barstard usually didn't converge at some point on the last day)

And as for the tommy getting near Vne, O yes it will quite happly sail through it within about 5-10 seconds after the rotation stops. Which is why people where over stressing the fin root and they had to put a plate in which I think is inspected every 150hours.

Anyhow the whole subject of spinning isn't one of standard solutions every aircraft is different. The POH is the bible. If the POH says don't spin it, don't. And if it says recover one way do it.

MJ

And the tommahawk is a bloody good training aircraft.

[SpannerInTheWerks]

Personally I have always enjoyed instructing in the Tomahawk. I accept it is not to everyone's liking - I'm not attracted to Ford Mondeos...but many are!

As for spinning - most of my more amusing stories relating to flying relate to spinning the Tomahawk:

1. The time I turned round and looked at the tail!
2. The time the engine stopped
3. The time I first spun the Tomahawk and felt 'unwell' - not from motion sickness, but from a sense that it wasn't going to recover (unfortunately hadn't been told/read that the rate of rotation increases when you effect a recovery!)

Happy days!

:O

[hugh flung_dung]

MJ - All the recovery procedures that I have seen require you to neutralise the controls, power to idle then apply opp rudder to direction of spin in there most basic form Just for the avoidance of doubt (in case anyone is following this thread and does not have much spin experience) the Standard Spin Recovery is:
Power off, ailerons neutral, FULL rudder opposite TI, short pause, stick progressively forward (or rearward if g is negative) until rotation stops. Rudder is NEEDED to decrease the rate of yaw, elevator is NEEDED to decrease the angle of attack. Unless the POH says do something different, or you are a highly experienced aerobatic pilot, stick to the standard spin recovery.
Someone else mentioned the Beggs-Mueller method: this requires that the stick is floating (not in your hand!) and does not work in a number of aircraft.

[Raw Data]

If you think spinning an Axe is fun, try spinning a Beech Skipper...

There have been, I think, two Tomahawks that lost their tails in New Zealand... one off Wanganui, not sure about the other. I seem to recall that the Wanganui one lost its tail downwind in the circuit.

I enjoyed instructing in the Tomahawk, miles better than a 152 (but then, I have wide shoulders). Not particularly impressed by the build quality though...

[robione]

Ive instructed on them so think i qualify to post an opinion.They are a very interesting a/c to stall and spin.One of the clubs i instructed at had several in the fleet and the stall behavior was different from one to the other.One in particular being a fierce wing drop at the stall if there was even a slight bit of yaw present.Although some are approved for spinning having had what i believe is the tail modification,i was never happy spinning in them.I believe spinning should be done in truly aerobatic a/c and training in light trainers should go no further than incipient spin recovery,that said its only my humble opinion.[ Im aware you dont have to teach it in the JAA syllabus]The spin in the Tomahawk is a damn site more lively than a 152 having spun both.If its your cup of tea fine, but i personally do not trust the Tomahawk spinning and count my lucky stars that im still in one piece having spun them on several occasions,but not no more,i just dont trust it having looked back at the tail and the spin recovery technique taking me near through the virtical,maybe im just getting old,but spinning in the Tommybomber i will leave to you chaps.

[whatunion]

aircraft bite fools dont they, and there seem to be plenty on here.

the worst mistake an instructor can ever make is to describe the stall/spin characteristics of an a/c as being they same as when they taught the exercise. eg pre-meditated.

who says the tomahawk dosnt spin like the c150/2. try going in off a full power entry. or an out of limits aft c of g and see how it spins.


the cherokee 140/180 is often described by instructors as having a non event in a stall or spin. i have even heard one instructor say it dosnt stall and he had a prof licence.

c of g which is very rarely mentioned, certainly not here, is the major key to spin characteristics and which contols are effective. i am amazed just how many of you have seemed to have carried out all these experiments while you are spinning to find out control effectivness.

i saw someone burn to death in front of me once in a pitt special. if he had of lived he would have told you that a pitt special with a second passenger and full tanks has quite different spinning charachteristics that one with half tanks and no passenger!

beware of dead experts