Handling qualities of DHC-2 Beaver

[Methusala]

I consider myself, along with most of us, an aficionado of all things with wings. I don't have formal aeronautical qualifications, apart from my experience flying many types of mostly ultralight aircraft. I am posting here so as not to directly divert from the feelings of grief in another thread. I read a lot of aero related stuff and recall a pilot report some years ago in the British magazine Pilot featuring the Beaver. I have loved the Beaver since the 1950's when the Snowy Mountains Authority flew a fleet of 6 from Polo Flat in Cooma. I flew as a passenger in VH-NOO a couple of years ago doing 3 landings including one on the Hawksbury River. Back to the pilot report. This stated that the aircraft was, because of the long and narrow chord wing, prone to savage wing drop at the stall. A local accident cost the agricultural pilot a leg and lucky to get away with his life, when it stalled and crashed while dropping super out of Tralee Station south of Canberra. It is important not to allow our love for a particular type to cloud our perceptions. A friend of mine was waxing lyrical about the Dromedary to its pilot on a visit to Forbes. The pilot responded quickly saying that it was just another aircraft and could kill you in an eye-blink. High aspect ratio wings cause gliders to have fairly aggressive wing drop in stalls. Try it in a Blanik.

 

 

[nomadpete]

Thank you for diverting this Avenue of debate onto it's own thread.

 

 

[djpacro]

I didn't go to the trouble of finding out what aerofoil section etc is on the Beaver so just plucked this figure from https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710021678.pdf A Design Summary of Stall Characteristics of Straight Wing Aircraft showing the typical effect of aspect ratio on stall margin distribution.

 

 

 

[David Isaac]

I didn't go to the trouble of finding out what aerofoil section etc is on the Beaver so just plucked this figure from https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710021678.pdf A Design Summary of Stall Characteristics of Straight Wing Aircraft showing the typical effect of aspect ratio on stall margin distribution.[ATTACH]53284[/ATTACH]

DJP,

If I read those graphs correctly, the lack of taper has a greater effect on stall than the aspect ratio alone.

 

Is that a correct interpretation

 

 

[derekliston]

Don’t want to buy into any of this straight wing, taper wing stuff, I just remember a quote from an old pilot about the DC3. (Tapered wing) “There are three rules about stalling a DC3. Don’t stall, don’t stall and don’t stall!”

 

 

[djpacro]

DJP,If I read those graphs correctly, the lack of taper has a greater effect on stall than the aspect ratio alone.

Is that a correct interpretation

Yes, taper plus washout and aerofoil section (especially different aerofoils spanwise). Most data around is for a steady, straight stall (without power/slipstream effects) however the stall margin distribution gives an indication of behaviour in other situations - a skidded turn, for example.

[Yenn]

I would expect the pilot of a Beaver to be conversant with the stalling characteristics of the plane, at least if it was a commercial pilot, not a learner.

 

 

[facthunter]

Beavers and Otters were used in PNG a far more critical situations and aerial agriculture had a fleet of them at Bankstown.. We keep hearing of these deadly planes. The beaver is a true utility plane with good control capability. The aspect ratio is not high by modern standards, the rudder is very effective. ATR's and dash 8's have far more critical wings. Icing shows this up and I'm sure that Alaska where there's lots of beavers you would get a good load of ice on now and again. Try a Mitsubishi Mu-2 or a Wirraway or even a Chipmunk if you are not ready. for dropping wings

 

.. Don't stall anything in a dynamic situation.( You are right on the edge).. IF you want to be safe. When all this stuff was current there was no real drama. Now Captain Marvel would have trouble with flying everything.. Everyone" wheels on" tailwheel planes (though It's normal with the DC3) Wingmen ( wingpersons) if there's a light breeze.. . Drama.. Nev.

 

 

[Happyflyer]

On the subject of Beaver flying characteristics you may be interested in this from the PPRuN forum on this subject. Sea Plane down in Hawksbury - Page 4 - PPRuNe Forums

 

Aviation Investigation Report A15Q0120 - Transportation Safety Board of Canada

 

Quote:

 

In the controlled conditions of certification, the stalling of the DHC-2 was described as gentle. However, as is the case for many other aircraft, a stall in a steep turn under power triggers an Incipient spin with few or no signs of an impending stall, and the flight path changes from horizontal to vertical. In low-altitude flight, stalling followed by incipient spin, no matter how brief, prevents the pilot from regaining control of the aircraft before impact with the ground.

 

Quote:

 

In 2014, Transport Canada and the manufacturer, Viking Air Limited, recommended that stall warning systems be installed, but only 4 have been installed on Canadian‑registered DHC-2s. There are currently 382 DHC-2s registered in Canada, 223 of which are used in commercial operations.

 

Level of risk is determined by the probability and severity of adverse consequences. Given the number of DHC-2s without a stall warning system in commercial operations, combined with the fact that low-altitude manoeuvres are an integral part of bush flying, it is reasonable to conclude that a stall at low altitude is likely to occur again. Because stalls at low altitude lead to catastrophic consequences, this type of accident carries a high level of risk.

 

Until, at a minimum, commercially operated DHC-2s registered in Canada are required to be equipped with a stall warning system, pilots and passengers who travel on these aircraft will remain exposed to an elevated risk of injury or death as a result of a stall at low altitude.

 

Therefore, the Board recommends that

 

the Department of Transport require all commercially operated DHC‑2 aircraft in Canada to be equipped with a stall warning system.

 

TSB Recommendation A17-01

 

Appendix C – TSB aviation investigation reports on accidents involving aircraft that stalled and were not equipped with stall warning system

 

Quote:

 

Accident Type Fatalities Summary

 

A14O0105 DHC-2 Beaver 0 The float-equipped DHC-2 Beaver aircraft (registration C‑FHVT, serial number 284) rolled to the left prior to the flare. The pilot attempted to regain control of the aircraft by applying full right rudder and right aileron. The attempt was unsuccessful, and the aircraft struck rising tree‑covered terrain above the shoreline. The aircraft came to a stop on its right side and on a slope. Two of the 3 people on board received minor injuries. The aircraft had no stall warning system.

 

A12O0071 DHC-2 Beaver 2 The DHC-2 floatplane (registration C-FGBR, serial number 168) stalled and crashed during a go-around while attempting to land. Two of the 3 people on board drowned. The aircraft had no stall warning system.

 

A11C0100 DHC-2 Beaver 5 The DHC-2 floatplane (registration C-GUJX, serial number 1132) stalled and crashed during takeoff. All 5 people on board received fatal injuries. The aircraft had no stall warning system.

 

A10Q0117 DHC-2 Beaver 2 The DHC-2 amphibious floatplane (registration C–FGYK, serial number 123) stalled and crashed during takeoff. Two of the 5 people on board received fatal injuries. The aircraft had no stall warning system.

 

A09P0397 DHC-2 Beaver 6 The DHC-2 floatplane (registration C-GTMC, serial number 1171) stalled and crashed during takeoff. Six of the 8 people on board received fatal injuries. The aircraft was equipped with a stall warning system, but it was not functioning, and the TSB identified this as a cause or contributing factor.

 

A08A0095 DHC-2 Beaver 0 The DHC-2 floatplane (registration C-FPQC, serial number 873) stalled and crashed while the crew was attempting a forced landing. Five of the 7 people on board sustained serious injuries. The aircraft had no stall warning system.

 

A05Q0157 DHC-2 Beaver 1 The DHC-2 floatplane (registration C-FODG, serial number 205) stalled and crashed during takeoff. The pilot, who was the sole person on board, received fatal injuries. The aircraft had no stall warning system.

 

A04C0098 DHC-2 Beaver 4 The DHC-2 floatplane (registration C-GQHT, serial number 682) stalled and crashed on approach. The 4 people on board received fatal injuries. The aircraft had no stall warning system.

 

A01Q0166 DHC-2 Beaver 3 The DHC-2 floatplane (registration C-GPUO, serial number 810) stalled and crashed on approach. Three of the 7 people on board received fatal injuries. The aircraft had no stall warning system, and the TSB found this to be a risk factor.

 

A01P0194 DHC-2 Beaver 5 The DHC-2 floatplane (registration C-GVHT, serial number 257) stalled and crashed on approach. All 5 people on board received fatal injuries. The aircraft had no stall warning system; the TSB noted this fact under "Other findings."

 

A00Q0006 DHC-2 Beaver 3 The DHC-2 (registration C-FIVA, serial number 515) stalled and crashed while climbing. Three of the 6 people on board received fatal injuries. The aircraft had no stall warning system.

 

A98P0194 DHC-2 Beaver

 

(modified: maximum weight increased) 0 The DHC-2 floatplane (registration C-GCZA, serial number 1667) stalled and crashed following a missed approach. None of the people on board were injured, but the aircraft sustained substantial damage. The aircraft had no stall warning system, and the fact that the pilot had no warning of the impending stall was identified by the TSB as a cause or contributing factor in this occurrence.

 

 

[facthunter]

I'm surprised they aren't fitted with a stall warning system. Is that the case in Australia also? Most planes from that era have them fitted and the places they operate from would suggest it would be needed.. I'm quite surprised about that . Its not small and carries a few pax. When people comment about their planes benign stall I'm always sceptical . I've long been a critic of how we cover stalling. recall the flying boat at Perth not long ago . Nev

 

 

[David Isaac]

That is a very enlightening read from Transport Canada. Obvious from benign to nasty in a split second.

 

I have flown the Beaver, one of Sydney harbour seaplanes ones actually many years ago but never that close to the stall. Nice aeroplane as long as you don’t want to go fast but need to carry lots of weight.

 

 

[Glenn Wilson]

I'm surprised they aren't fitted with a stall warning system. Is that the case in Australia also? Most planes from that era have them fitted and the places they operate from would suggest it would be needed.. I'm quite surprised about that . Its not small and carries a few pax. When people comment about their planes benign stall I'm always sceptical . I've long been a critic of how we cover stalling. recall the flying boat at Perth not long ago . Nev

Best advice for anyone flying - Go out with an instructor in a suitable and capable A/c and stall the beejesus out of it. All speeds, fully developed spins, all attitudes and all kinds of recovery techniques. Demystify the stall and the spin. Then when it actually happens in your "gentle stalling A/c' your reaction/response is automatic and safe.

I once did a dynamic stall in a Drifter of all things. Flying, turning and in a blink we were not flying. Nose down and rudder fixed it before the ground did.

 

 

[facthunter]

IF you haven't trained to limit conditions how are you expected to handle it when it happens?. Not only that, your underconfidence just doesn't allow you to do your best in assessing and coping with the situation. You can't know what you don't know. Nev

 

 

[ClintonB]

Maybe we need the training syllabus to be expanded to cover this more as part of our RPC. I know our local Sportstar was placarded "no spinning" and the stalls done during basic exercises introduces you to the buffet and gentle nose drop that occurs. I was told that using the buffet if occurs will indicate that you need to correct before the stall, But this does not help if you are caught out by inattention or distraction and a wing drop occurs. From what I have read not every plane uses the same recovery technique, so hard opposite rudder, close throttle, ease rudder off as spin stops, then exit dive gently may not help(this is what I have tried to remember just in case it is ever needed)- especially if you are too disorientated to figure out which way the spin is to start with. I would like to go somewhere and do a solid block of training in upset recovery with a good and patient instructor, I would consider this a good insurance policy for longevity.

 

 

[djpacro]

Maybe we need the training syllabus to be expanded ......

Done, see Part 61.

[facthunter]

You clearly cannot do the training you would like in an RAAus plane.. Even spirals are not permitted to be demonstrated. You need a substantial and aerobatics capable plane to do it in. The" recovery from unusual attitudes" programme I have always recommended. This is NOT aerobatics but requires a similarly strong and certified plane to allow for the pilot getting the plane into difficulties, where recovery may entail strong airframe loads. This training may save your life many times in a lifetime of flying, and certainly improve your skills base. Nev

 

 

[Yenn]

There are some aerobatic planes on the RAAus register. We are just not allowed to make full use of them.

 

Funny thing is aerobatics are forbidden, but there is nothing stopping slow flight. Much more dangerous in my opinion and I enjoy it in both my planes.