Sunday, March 18, 2007


Steve's "Otter Of The Week"! Karl E. Hayes

As we have seen previously, the Otter has been the most important aircraft in Canadian history for accessing "remote" places, which led to development. The Otter also has a "fine" history across this great land for "protecting and policing" our "Natural Resources". Read about one such Otter still employed by the Manitoba Government to this very day. First, though, some info on the "Vazar Turbine Otter". All information is from Karl Hayes' "masterful" CD entitled:

De Havilland Canada

Also, at the very end of my "Post", find Karl Hayes' "Contact and CD Info"......


The Cox Turbo Otter, in its original form at least, failed to achieve success as it was too complicated. Many modifications had to be made to the basic Otter, particularly to the fuel system. The expense and time needed to test and verify these modifications, and to rectify difficulties encountered, caused the project to founder. The problem with the Otter remained, however, how to modernise the aircraft to give it the extra power it needed and improve its engine reliability. The next attempt at a solution adopted a much simpler approach, and got it right.

Dara Wilder was a pilot, inventor and manufacturer of mining and oil-extraction equipment. He knew the value of a big aircraft such as the Otter, able to transport men and heavy machinery out to the mines, and he could see that the solution was to replace the radial engine with a turboprop. He set some stringent, but realistic, requirements which were to ensure the success of his idea. The conversion had to be in the form of a bolt-on modular unit that would require no airframe modifications aft of the firewall. The conversion kit had to be simple enough to install in the field. Like the original Otter, the turbine-powered version had to be certified on wheels, floats and skis, as well as for commercial IFR operations.

Interestingly, Dara Wilder's project got going in 1984, the year the Cox Turbo Otter “bit the dust”, literally. The engine installation was designed by Floyd Perry of Salinas, California who was a veteran of turbine conversions. The engine selected was the Pratt & Whitney PT-6A-135, the same 750 shaft horse power turbine used in the Beech F90 KingAir. Since the engine was several hundred pounds lighter than the radial it replaced, it had to be hung quite a distance forward of the firewall to keep the aircraft's centre of gravity envelope in the right place. The result was the long, pointy nose which is characteristic of all turbine conversions of the Otter. To keep the conversion as simple as possible, the new engine mount attaches to the same four mounting points used by the Otter's original engine.

One of the things Wilder and Perry had to do during the certification process was to prove to the satisfaction of the FAA that the Otter's airframe would hold up under the additional torque loads imposed by the more powerful turbine engine. They had acquired Otter C-FDIV (453) which had crashed in 1982 and which had been brought to the Serv-Aero Engineering facility at Salinas, California where it was in use as the non-flying prototype, on which the engine installation was first performed and tested. This airframe was jigged up and instrumented, and then carefully monitored twisting forces were applied to simulate the torque loads of different power settings. The results were impressive, the airframe going not merely to the engine's 750 shaft horse power, but to over 1,200 horse power without flinching. As a result the engine mount can also accommodate the more powerful PT-6A-145 engine, which develops 1,150 shp. The fuselage of C-FDIV was later transferred to the Aero Flite Industries facility in Vancouver, where many of the turbine conversions were to be performed. It was used there as a ground instructional airframe, engineering trainer and demonstrator.

The flying prototype of the Vazar Turbo Otter, as this conversion was called, was Otter number 22. A one-time RCAF aircraft, it was subsequently operated by Gateway Aviation and then by Turn Air. It was advertised for sale in May 1985 with 10,800 hours on the airframe. Registered N9707B, it was converted to a turbine by Serv-Aero Engineering at their Salinas, California facility during 1987. In August 1988, N9707B flew from Bellingham, Washington to Ketchikan and Wrangell, Alaska where it was demonstrated to local operators. Four years after the project started, the Vazar received its certification on floats in the United States in November 1988. Canadian float certification followed in June 1989.

Most devotees of the Otter prefer the look of the original. The round, radial engine is much more attractive than the long, pointy nose of the turbine. The piston engine original also sounds like what an Otter should sound like. It should not sound like a King Air! Points like this aside, it has to be said that the turbine conversion has greatly improved the DHC-3 where it matters, in its performance. The lighter engine, giving a weight saving of 730 pounds, provides a payload increase of the same amount. An increase of 150 horse power enhances all areas of performance. Cruising speed is increased by 43 mph, rate of climb is increased and take off and landing distances reduced. The engine gives much greater reliability and the TBO has increased to 3,500 hours. The Vazar is certified for IFR, allowing it to be operated at night and in the short days of the northern winters. It provides a much more dependable operation in severe weather and a much improved economy of operation. The Vazar is certified to carry 16 passengers.

Commercial development of the turbine Otter was undertaken by Dara Wilder's company, Vardax, based at Bellingham in Washington State. The company formed its Vazar Aerospace Division for the project. The Bellingham location is however only an administrative and marketing office. Operators of Otters wishing to convert their aircraft to Vazar dash 3s can either purchase a conversion kit and undertake the work themselves at their own base, or have the work performed by any contractor who specialises in the conversion. Many such conversions have been undertaken by Aero Flite Industries at the Vancouver International Airport. As John Hill of Aero Flite explained, the engine comes from P&W Canada in Montreal, Serv-Aero builds the conversion kit at Salinas and Aero Flite mates the engine and the kit to the Otter in Vancouver, to produce the DHC-3T Vazar Turbo Otter. Other companies specialising in this conversion are T.C.Aviation in Saskatoon, Saskatchewan and Recon Air in Geraldton, Ontario.

As at December 2004, 68 Vazar conversions had been completed, making this by far the most successful of the Otter turbine conversions.

Otter 429

Otter 429 was delivered on 1st October 1962 to the Ontario Provincial Air Service (OPAS) as CF-ODY, based at Sault Ste. Marie. In September 1972 the registered owner was changed to Province of Ontario, Ministry of Natural Resources, registration C-FODY. The Otter faithfully served the Province for 27 years, with only one minor incident. It continued to fly for the Province of Ontario until May 1989.

It was then transferred to the Province of Manitoba Air Services, Winnipeg, where it joined Otters C-FMAU (74) and C-FMAX (267). On 16th June 1991, the pilot landed at the water base at Island Lake, Manitoba but was unable to taxi to the dock because of the high wind and wave conditions. The pilot decided to fly over to a sheltered dock nearby but on take-off a wave hit the right float and collapsed the first compartment. The aircraft ended up partially submerged. It was repaired and returned to service. The three Otters are based at Winnipeg but deploy to other locations during the summer months, including Lac du Bonnet. ODY was noted here on floats in May 2004, flying fuel drums to such places as Berens River and Bloodvein in support of fire bomber operations.

***Latest Update!***

Otter 429

C-FODY. The Province of Manitoba Air services arranged for two of its Otters to be converted to Vazar turbines. The aircraft in question, C-FMAX (267) and C-FODY (429) routed Winnipeg to Calgary on 30 March 2005 and then onwards via Golden, BC, to Vancouver where they arrived on 2 April. C-FODY entered the Aeroflite Industries hangar at the Vancouver International Airport where the conversion work was performed. C-FMAX was converted by Viking Air at Victoria, BC and it passed through Calgary at the end of May 2005 on its way back to Winnipeg. C-FODY was noted outside the Aeroflite hangar at Vancouver on 18 June 2005, its turbine conversion completed and about to depart for its return trip to Winnipeg.

Later in June, both MAX and ODY were flown to Wipaire at Minneapolis, Minnesota where they were fitted with Wipaire 8000 amphibious floats, before returning to Winnipeg. In January 2006 both Otters were flown to Rocky Mountain Aircraft at Springbank near Calgary for a new avionics fit, then in April to Red Deer, Alberta for repainting into a new red and white colour scheme, then back to Springbank for finishing off and return to Winnipeg end April, in time for the summer 2006 season. These two Otters are the very last Otters still in government service in Canada and as they have now been updated with turbine engines and state of the art avionics, they are set for many more years of government service.

- by Karl E. Hayes

Otter C-FODY, still serving the "Province", and "protecting the wilds"!

WEBSITE - Vazar Turbine Otter

ODY gets her "turbine"!

ODY in Bissett, Manitoba, "back at work"!

"Great information, Karl"!

CONTACT and CD INFO - De Havilland DHC-3 OTTER - A HISTORY by Karl E. Hayes

Comments: Post a Comment

<< Home