Topic: Chippie spinning

[BAMTSW]

I've read a few tales about the Chipmunk's spin characteristics and it's hard for someone with little or no experience in them (such as myself) to separate the BS from the truth. Anyone care to give us a first-hand account of how she behaves? Just curious...

[Dean Cross]

Well Al,
 My Chipmunk spinning is hardly vastly exprienced, but it is current....
The story is something like this...............
Bought Chipmunk,terrified of the legendary Chipmunk spin. Spoke to a couple of SKY GODS and the sum total of the wisdom was
1. Make sure the brakes are off before spinning
2. Both hands on the stick during recovery

My first spin sortie was with an ex Chipmunk, Piston Provost,Vampire, Canberra,Bucaneer etc Pilot. Well briefed, as per the flight manual....oh and by the way ...you are in the back seat as that is where you will be teaching it from...........

Was I comfortable?    Of course not!

45Mins Later I was all checked out to continue learning........

What did I learn???
The civilian flight states three different possible spin phases forthe DHC-1.
1.Semi-stalled spiral dive
2.Normal spin which flattens after 3-4 turns
3. Oscillating spin

I have experienced all three

Semi-Stalled spiral normally follows the Airline Pilots entry(reluctance to apply and maintain full pro spin control)
Normal spin with a well rigged airplane
Oscillating when engine idle too high /or ailerons miss-rigged

All are fully recoverable as per AFM instructions(p.s. I have had a couple of heart in mouth moments)
I think the two main myths about the Chipmunk spin are
1.People fail to recognise that when recovery control is applied, the spin speeding up means you are about to come out..and
2. you think you have full forward Elevator when in fact it is not even  neutral...keep on pushing smoothly through the buffet.

I have had my DA authorising officer preach to me about spin exit on a heading , when after several attempts he conceeded "its not quiet like a Pitts" ( I think he was happy she came out actually)

P.S. Never Spin a well Aerodynamically designed aeroplane without a chute strapped to your bottom.....Ask me how I know this???

This subject is a"can of worms...but the Chipmunk does "exactly what it says on the tin".
Hope this helps...I am sure there are more experienced offerings out there???    

[BAMTSW]

Excellent stuff. I would assume then that the Müller-Beggs recovery technique is a smoking-hole-in-ground option?

You'll have to elaborate on the 'chute comment.  

[Dean Cross]

Muller recovery technique not recommended    

[Dean Cross]

I think my first Chipmunk student should comment on the "chute" advice

[Martin]

WEll what can I say?  

After an 'Interesting' past, I have completed one or two 'jumps'. I met and and was taught aerobatics by an excellent instructor  

During that training we discussed low level manouvers and the 'what happens if...' conversation cropped up.

It was MY opinion at that time that trying to leave an aircraft which was perfoming at low level would never be survivable... so why use the 'chute'?.. after all its heavy, uncomfortable and restrictive.

However!!! after learning the basics, and expanding my learning I have seen some amazing occasions when at very low level, i.e. less than 1000ft pilots have managed to struggle from an airframe, deploy and walk away.

If MORE than one person can do this, then I advocate ALWAYS using that and any other aid (Helmet/suit/gloves/boots), which might help any of us engaged in such pursuits......   no matter how hard other people laugh!!

Of course, this is just my opinion, what does everyone else think??

 

[Rob Merrylees]

The DHC-1 Chipmunk is not at all dangerous to spin provided :-
1) You have sufficient height for recovery
2) The correct recovery technique is used.

A large number of fatal accidents  involving spin recovery training occured when the DHC-1 Chipmunk was first introduced in Australian Aero Clubs.
It is thought that this was brought about by previous experience with Tiger Moth aircraft that did not require the same degree of positive spin recover technique.

The Royal Aero Club of NSW later placarded their Chipmunk Aircraft with the simple instruction, "To recover from a spin apply FULL opposie rudder and FULL foward elevator" or something similar.

The technique I use is FULL OPPOSITE RUDDER and then ease the control column progessively forward.  An increase in the rate of rotation may be felt. This is a good sign that the recovery action is working and when the airspeed builds up the aircraft will stop rotating .

The Chipmunk is actually reluctant to spin.  Using a power off, steady deceleration to stalling point and then applying rudder with opposite aileron, the Chipmunk will most likely enter a stalled spiral dive before flattening out into a true spin.  Once the aircraft has entered a true spin it takes some effort to move the control column forward.

There was an incident in Australia where a Chipmunk had a rudder cable break while in a spin.  The instructor took over control and was able to recover using elevators and aileron alone.  This to my mind illistrates the importance of elevators in the spin recovery process.

My introduction to the Chipmunk was undertaken by an experienced former World War2 instructor.  Without any pre- flight briefing or warning as to what might happen he asked me to do a steep climbing turn, continuously urging me to climb steeper, turn harder.   Of course the inevitable happened and the aircraft stalled , flicked over on to its back and then down into an incipent spin.  Power off, opposite rudder , stick forward and I pulled out of the dive.  Staisfied, he simply said,  "Thats enough upper air work, lets go back and do some circuts".  Since that time, Chipmunk spins have held no terror for me!

[Dean Cross]

I could not agree more on the importance of elevator Rob. I think pilots think the Chipmunk elevator is forwrd when the stick is just under the instrument panel, whereas it is just forward of neutral elevator.
As part of departure( from controlled flight) awareness, I like to ask students to enter a steep turn with high power and pull through the buffet, the aeroplane departs and control is easily regained by re-applying the airflow( stick centrally forward), even without touching power or rudder. In fact this is so controllable that the machine can be made to depart from a steep turn to the right and forward stick at the appropriate time leaves it in a steep turn to the left.I think that really builds confidence in the student ( also makes them respect the buffet). Steep turns to the left then follow with departure to the inverted, stick forward,control regained,roll to the nearest horizon and recover from dive. Throttle is closed during this one to minimise speed build up but the elevator is the magic control.
Mis use of the rudder at low speed can make things worse in any aeroplane, unload the elevator and ,altitude permitting , win every time

[Rob Merrylees]

In the last paragraph describing my instructors urgings I forgot that as well as telling me to "climb steeper, turn steeper" he added "use more rudder, put on full rudder".   As you describe, I seem to recall that he got me to do a left hand turn!

[Neil Bordessa]

I spin the Chippie every time I do aero's to keep my hand in and use the same technique as Rob Merrylees, I have found this method works well for me.

[Dean Cross]

Neil,
Is that the same entry technique, recovery or both?
Do you find the entry and recovery characteristics are different depending on the C of G?
Solo I find is more difficult to enter but much quicker to recover!(55kts full application works a treat for entry).
Declan
Sorry guys, for me aileron usage during departure from controlled flight is only an emergency recovery technique after the standard recovery has failed. The only time I had a nasty neither/nor spin was when I performed the airline pilots entry,"gently does it, no full positive application of anything, that might get me into trouble!"
If it will not go in using elevator and rudder alone, it is a rogue, and should be treated with caution!

[Neil Bordessa]

Sorry did not make it clear, it was the same recovery method. The entry is the same as yours 55kts, back on the stick then full rudder. I don't always get a clean entry   though..... any tips?

[Dean Cross]

Neil,
Is it any easier when you are dual or solo?

[Bob]

Assuming you have read the TNS on spinning, here's a further interesting note;
http://www.dhchipmunk.com/spinning.htm

I have the TNS as a pdf file if anyone wants it.
Bob

[chipmunkflyer]

Intersting discsussion on spinning .. one or two historical notes:-

The increased rudder area, although requested by Boscombe Down after testing both G-AJVD & 'KDN in December 1948 was actually asked for by the test and demo pilots of de H Canada and first flown by George Neal in mid 1949 and incorporated from October 1949 on the DHC-1B-2 model.

The first aircraft tested here in the UK was WB 550 in April 1950 at Boscombe Down and was on test at the time that the first RAF spinning accident occurred at Oxford UAS ... the fact that WB550 was on test at that time with the enlarged rudder was used as an excuse to assist spin recovery at the subsequent enquiry and thus the myth was borne.

As a result of differences between the Tiger Moth and the Chipmunk at spin entry John Derry toured the RFS & UAS units in 1950 demonstrating the use of opposite aileron during spin entry to resolve this problem .... George Neal, the Canadian test pilot, had learned this technique from Russ Bannock way back circa 1947 when he took over the Chipmunk testing programme .... thus the early RAF Chipmunk PN shows on page 27 the use of opposite aileron as an entry technique. Interstingly no mention is made of holding it neutral once entered.

One other point of interest ... the Canadian model has only eighteen inch stall buffet strips whilst the UK model retains the original thirty inch one.
George Neal found that by gradually reducing this item it lessened the buffet at stall/spin entry and also gave better entry to the spin. Thus the Canadians have never seen the point of using anti spin strakes on their model.

I also discovered recently that following two spinning accidents years ago the Portugese Air Force removed spin training from the syllabus ...  they have however taken the precaution of adding anti-spin strakes to their model as it was built under licence from the UK.

I have also added a post to the side slipping discussion

Best

Rod