Aircraft Review : de Havilland Canada DHC-6 Twin Otter -300 Series by RWDesigns
DHC-6 Twin Otters were quite thin on the ground for X-Plane a few years ago, but now that has all changed. First there was a great conversion of Syd Adam's version by Pedro van Leeuwen into his own freeware aircraft, and this was a great conversion. But it still had mostly default X-Plane switchgear and instruments and considering this the aircraft has still been overwhelmingly very popular. Now Jetsim has released their own payware version and this version is a complete ground up built aircraft of the veritable famous "Twotter".
The DHC-6 is a Canadian 19-passenger STOL (Short Takeoff and Landing) utility aircraft developed by de Havilland Canada and is currently produced by Viking Air. Some places note the aircraft is not in production anymore, but it is. After Series 300 production had ended in 1988, the remaining tooling was then purchased by Viking Air of Victoria, British Columbia, who manufactured replacement parts for all of the out-of-production de Havilland Canada aircraft. On February 24, 2006, Viking purchased the type certificates from Bombardier Aerospace for all the out-of-production de Havilland DHC-1 through DHC-7 aircraft. The ownership of the certificates gives Viking the exclusive right to manufacture new aircraft. Currently the production restarted on July 17, 2006, at the Farnborough Air Show as Viking Air announced its intention to offer a Series 400 Twin Otter. On April 2, 2007 production of the Viking Twin Otter, equipped with a more powerful Pratt & Whitney Canada PT6A-34 engine was initiated and construction began and Zimex Aviation of Switzerland received the first new production aircraft, serial number 845, in July 2010. As of summer 2014 Viking has already built 55 new Series 400 aircraft at their Calgary facility. Serial number 900 took flight in spring 2014. The production rate as of summer 2014 is approximately 24 aircraft per year. To date there has been just under a 1000 Twin Otters of all series produced.
Development of the aircraft began in 1964, with the first flight on May 20, 1965. A twin-engined replacement for the single-engined DHC-3 Otter retaining DHC's renowned STOL qualities, design features included double-slotted trailing edge flaps and ailerons that work in unison with the flaps to boost STOL performance. The availability of the 550 shp (410 kW) Pratt and Whitney Canada PT6A-20 propeller turboprop in the early 1960s made the concept of a twin more feasible. To bush operators, the improved reliability of turboprop power and the improved performance of a twin-engined configuration made it an immediately popular alternative to the piston-powered Otter which had been flying since 1951.
The first six aircraft produced were designated Series 1, indicating that they were prototype aircraft. The initial production run consisted of Series 100 aircraft, serial number seven to 115 inclusive. In 1968, Series 200 production began with serial number 116. Changes made at the beginning of Series 200 production included improving the STOL performance, adding a longer nose that was equipped with a larger baggage compartment (except for aircraft fitted with floats) and fitting a larger door to the rear baggage compartment. All Series 1, 100 and 200 aircraft and their variants (110, 210) were fitted with the 550 shaft-horsepower PT6A-20 engines.
In 1969, the Series 300 was introduced, beginning with serial number 231. Both aircraft performance and payload were improved by fitting more powerful PT6A-27 engines. This was a 680 hp (510 kW) engine that was flat-rated to 620 hp (460 kW) for use in the Series 300 Twin Otter. The Series 300 proved to be the most successful variant by far, with 614 Series 300 aircraft and their sub-variants (Series 310 for United Kingdom operators, Series 320 for Australian operators, etc.) sold before production in Toronto by de Havilland Canada ended in 1988. (wikipedia).
Performance : Maximum speed 160 knots (297 km/h at cruise altitude) 170 knots (314 km/h at cruise altitude) : Cruise speed 150 knots (278 km/h at cruise altitude) : Stall speed 58 knots (107 km/h at cruise altitude) : Range (Max fuel, no payload) 771 nmi (1,427 km) 775 nmi (1,434 km) 799 nmi (1480 km) 989 nmi (1832 km) with long range tankage : Service ceiling 25,000 ft (7,620 m)
RWDesigns de Havilland Canada DHC-6 Twin Otter
Yes this is a great looking Twin Otter from RWDesigns (formerly Jetsim). It is the long nose version (no notes on if a short nose version will happen?) and finally we have a quality version of this great and versatile aircraft. These short distance regional aircraft are some of the best to fly in X-Plane, because they are just that... very versatile. They give you great flexibility in island hopping or airport hopping around touristy areas and delivering people and cargo to remote areas and even supplying supplies to people who have a habit of doing badly planned adventures and even then saving them from themselves (or mostly getting them back to the nearest hospital). In most cases you need an aircraft like the Twin Otter in most or all of those scenarios.
Modelling wise the Twin Otter is pretty good, with great detailing of rivets and paneling from the X-Plane "draw per pixel lighting" shading effects and aircraft body fittings, although it is still a high step up into the cockpit. looking up the cockpit looks excellent in detail. This is the office and you will spend a lot of time in here and so you will require it to be very good... thankfully it is. The Twin Otter cockpit is quite short as the pilot's and co-pilots seats are resting closely to the rear cockpit bulkhead, there is not much room in there or space. the two yokes are on a V central column and are expertly created. the main power (throttle), feather and fuel (cutoff) levers with the flap selector set out behind are all arranged on the centre overhead box structure.
Once up in the left hand pilot's seat the panel looks quite basic for a two engined regional aircraft. The pilot gets most of the instruments and the co-pilot really gets only the standard six instrument pack and a turn indicator. Power "on" is on one of two small switch panels on the left and right side of the main overhead structure. If you want the main switchgear then it is directly above your head and right up against the rear cockpit bulkhead.
Main panel lighting are three rotary knobs right above you rear with two for the Panel/Eng-Inst pilot (left) and one for the radio/co-pilot (right). twirl them all up and the overhead and panel comes to life. And it all looks really great. Point to be aware of is you need to set your X-Plane views to cater for this straight up extreme switch and knob position, you will go up here quite a lot and you need to get there and back quickly.
Not everything though is now switched on... you have to also now switch on the equipment stack one radio set at a time. A feature I really like, because it is very realistic. You have the 10.30 Garmin GNS 530 gps with a pop-out screen, to turn on it is a two button press activation with the .C button first and then an "OK?" by pressing the "ENT" button. Below is Bendix/King KX155A TSO which is COMM 1/NAV 1 only (sorry no COMM 2/NAV 2). Next down is the KT 70 TSO Transponder and finally a KR 87 TSO ADF radio set. You will find the equipment here more interactive with more changes than the standard radio sets fitted to X-Plane aircraft, button work and settings can be changed more than the basics... The KR 87 TSO X-Plane manipulators however are quite difficult to use, the worse are the smallest -/+ adjustments, they are also very hard to find sometimes. Top of the equipment stack is the standard KMA 28 TSO audio selection panel.
No NAV2/VOR 2 direction finding is a real loss in an aircraft of this type? The NDB setting doesn't give you enough range and as we will see you have to take short routes across open water. I found a trick around this by using the GNS 530...
Find the VOR radial that you want and put it into the GNS gps as a "direct" position. In this case it is "SSR" TACAN RAF Lossiemouth, Scotland. It will give you range, direction and your position. The good news is that the GNS can accept VOR radials.
The autopilot in the DHC-6 is a Collins AP106. the system is centre right on the panel and the altitude selection is just below. The altitude selection works with two buttons on the upper top of the pilot's station panel. There is an activation and adjustment button and knob missing from the AP panel... I'll let you think about that one for a moment.
Engine display panel is beautiful, with great lighting. Dials include - Torque Pressure Gauges - Prop RPM Percentage Gauges - T5 Temperature Gauges - Gas Generator RPM Gauges - Fuel Flow Gauges - Oil Temperature Gauges - Oil Pressure Gauges and Fuel Quantity Gauges LEFT gauge is AFT and RIGHT gauge is FWD. An excellent Fire protection panel and DC Volts/Load Indicators. As my route today was quite long, I have put in 13 X 100 Ibs of fuel in each tank
On the centre yoke support column is your "Yaw" damper button and the trim knobs are down by your right arm rest.
Overhead is the twin throttle levers and propeller feather levers, far right the two fuel valve levers, all are excellent with the throttles levers having built in reverse thrust. Small panels either side cover electrics/landing lights and starters on the left and wiper switches on the right. The lighting switches are set out all over the rear of the overhead panel so you have to remember their placement, De-iceing and heating switches and controls are all up here as well. Detailing is great with attention to detail like with this overhead light and switch.
Flying the DHC-6 Twin Otter
One of the most highly used routes of the talents of the Twin Otter are found in the upper top reaches of Scotland and the accompanying northern islands of Orkney and Shetland. So my route was from Aberdeen/Dyce (EGPD) to Kirkwall (EGPA) via Lossiemouth and Wick, then on to Sumburgh (EGPB) in the lower Shetlands. The return route was a nonstop flight back to Aberdeen/Dyce via Kirkwall and Wick and then direct back over the water to EGPD. The area is suited well for the Twin Otter, but it is also known for its constantly variable changeable weather and add in a mid-February winter period and it was going to be interesting flying.
There are two baggage compartments with one in the nose and a larger one aft of the passenger cabin. All doors open by a hand on the inside of each door (including the pilots/co-pilots doors), here a door menu would be a better fit, as the two baggage doors are quite hard to open, as you have to find the doors from the inside to open/close them? At least you can just twist around in the cockpit to open/close the main passenger doors through the cockpit/cabin opening.
Passenger cabin is bright and cheerful, but a bit too bright with the cabin lighting switched on. Great baggage seen in the compartments and with the passengers on board we are ready to depart to Kirkwall.
Engine start is quite easy. Ignition "on" for each engine and make sure the fuel and feather/prop levers are forward, then flick the starter switch on which engine you want to start. The process is automatic and it will take a little while to turn over and power up.
You will need a little power to get the aircraft moving, but in the taxi mode it is quite easy to control, just make sure to control the taxi speed. Lighting is fine with two landing lights in the wings and a small taxi light on the front nose gear. It's not brilliant but good enough for what you need. The landing lights will work on/off by the X-Plane menu (set on my joystick), but the taxi light has to be switched off manually... which means a visit to the overhead panel every time to just do that.
You set the flaps by the positioner on the overhead panel and the flap position is shown on the central window strut. The system is not notched but a continuous linear movement up or down, so you can set them where you like within the flap range of 0º to 40º
Most aircraft are built to a compromise. In the Twin Otter's case it is it's low speed and STOL (Short,TakeOff and Landing) capabilities. These aspects are great in their right situations, but can work against you in other areas. In the Twin Otters case it is its speed and climbing ability, so this aircraft is not going to win any awards in either of those areas. That huge tail works against you in other ways as well. I found the aircraft is not great in cross winds, so taking off in a stiff crosswind North Sea breeze is going to make the aircraft a handful. You will have your work cut out at low speeds until that tail starts to bite the air. So your yoke is a blur and your working the throttle to get the best compromise of keeping the aircraft sorta straight. Once you get to a certain built up movement of speed the aircraft settles down quite nicely and once in the air is also nice and easy under the yoke and rudders. You are not going to do aerobatic turns or somersaults in a utility aircraft like this but it will turn and climb well within reason. A small annoyance is that after leaving the runway the wheels will continue to rotate? they will go on turning like this for ages unless you use your brakes to stop them, If you do use the brake then make sure that it is off again to land... or you may go and burst your tyres.
If you have looked closely at the Collins AP106 system you will notice there is no V/S (Vertical Speed) button or V/S climb or descend knob? The Collins system does not use that type of system to climb or descend, instead it works this way.
You set your speed and pitch (usually at 1000fpm) and then turn on the Collins AP system by the switch, then to activate you then press the IAS (speed) button to maintain the climb (pitch) and lock in the speed you have chosen. The aircraft maintains the pitch and holds that speed, and once it has settled its position you can actually change the pitch up or down by using more or less throttle... but the speed stays the same. It works quite well once you are familiar with how it works and how it adjusts your pitch, the tricky part is getting the right pitch and speed to be locked in at the right point so the transition from manual control to auto control is smooth and the aircraft does not go nose down and then pick up speed to adjust itself.
At first I didn't like it or was simply not used to that way of adjusting my climbing vertical speed. But time and practise and I can now easily set the system smoothly, it is just getting both pitch and speed correct. As the aircraft climbs and the speed stays constant then the vertical speed will adjust to the power available and your pitch will decrease from usually 1000fpm to around 500fpm, and it works very well when you are used to it. You set the "ALT ALERT" on the panel to tell the system when the set altitude (8500ft) is achieved and the aircraft will then level off and release the throttle hold, you then need to adjust your throttle speed to the airspeed you require. The speed band is quite small with 90knts minimum and 140knts the usual cruising speed or 160kts if you are really lucky.
Once in the (slow) cruise Scotland turned on an early cold morning soft misty light show. And as the sun rose more I headed north.
The cockpit is a nice place to be. You work hard in the office of the Twin Otter, but the rewards are there. Those big Pratt & Whitney PT6A-27 turbine turboprop engines are right there powering away in the background. Sound from them is not extreme but still constantly slightly high. Overall the sound is very good but not exceptional. Sound is also 3D directional and non-adjustable.
With the Scottish Mainland behind me I headed up to Wick and then the islands started to flow under the aircraft. Close up detail of the aircraft in flight shows good detailing of the wings, tail and I like the external metal plates that strengthen the hold of the wings on to the fuselage... gives you good feeling that they won't blow off.
Arriving at my first port of call in Kirkwall, Shetland and I found it difficult to lose height? Pulling back the power and pushing the yoke full forward still means the aircraft was slow to drop down, holding the IAS button on and no power didn't work either?
I finally got the aircraft down to a 1000ft and studied Kirkwall below from a bypass, before looping back around to RWY27. I had good reasons to check out the lay of the land, as the blustery North Sea wind at Aberdeen was now a full blown gale of 20kts, I didn't so much land at EGPA but crab in totally sideways. The low Twin Otter 75knt landing speed gives you more space and it is very wide. once down reverse propeller thrust can stop you within a very short distance, it looks and sounds great from the cockpit as well.
I was down and my passengers still were on friendly terms with me as well. But I was not happy with my approach or landing at all, at least the route did not end here so I would get more chances to put things right.
It was mostly going to be all over water to the next stop at Sumburgh (EGPB) lower Shetland. And almost when I had reached my height of 12,500ft and as quick as a throwback of a dram of Scotch the weather turned even worse and darker. I climbed more up to 10,000ft to get above the cloud tops, but the Twotter did what it was best at... just kept on Twottering along.
Liveries
There is not a great selection of liveries, because the Twin Otter has so many operators it would be impossible to cover even a few of the best... The painters are going to have a field day with this aircraft.
There are seven liveries, two white in clean and dirty, A British Airways, British Antarctic Survey and Royal Canadian Forces designs and a Maldivian Air Taxi. The other one is the Flybe livery in use.
It was time to descend and I checked out the manual to see if I had done anything wrong, as this Collins AP system is quite different from the standard V/S versions.
Well I had missed something and that was you had to not only set your throttles to idle... but also feather your propellers as well? I did this and down slowly I descended. It was odd (and slightly disconcerting) just having the props just windmilling around out there with only the sound of the wind showing you your speed. You have to get you distance to height right as you drop usually at 1000ft per minute. I found that if you adjust your feather angle (I have mine set up on my keyboard) you could adjust the pitch from 1000ft to 200ft per minute to get the best glide down. The IAS switch on the Collins has to be on and you select the "MDA" button (minimum descent altitude) to target the set altitude like you did earlier before when going up.
I pulled the throttle power back in to give me more power as the MDA reached clickoff point to get a smooth transition from descending to powered forward flight. Down at 1500ft I couldn't see anything in front of me though the foggy windows, and I knew on the approach to EGPB that there was a big dirty mountain of a rocky point to the left of me. I saw it finally through the gloom and used the ILS Horizontal Situation Indicator alignment to guide me to end of the runway 09. The ILS beam is actually offset on RWY09 and too tricky to use in these conditions, so I just used the beam to align the Twin Otter with the runway and flew down the runway to get the correct bearing and wind direction, which I found that RWY33 would give me a direct approach with the wind directly behind me which is hard enough, but at least the bluster is not throwing me stupidly sideways.
A clear 90º to 90º circuit to RWY33 and the approach was perfect and I was soon down and parked up. The Twin Otter comes with full systems including Electrical, pneumatic, hydraulic, Anti-Ice and Fuel System.
Return to Aberdeen Dyce was a straight through route. So I set up the Garmin GNS to cover all the bases including a few waypoints over the water section. I like to fly VOR to VOR but here I wanted to test out the NAV gps system.
My route was just under 250nm and I was going to fly at 12.500ft. Just a quick ride home was the idea... but coming over Kirkwall you could see my problem? I had a 22knt headwind, and at that point only a 120knt groundspeed, it was going to take hours to get back to EGPD and it did. But that is not a bad thing in here. I just sat back and enjoyed the flight back, I had become quite smitten with this aircraft and you can see easily why it is so popular.
Over Wick I turned out over the North Sea and headed for the Scottish mainland. Once the coast was in view I was ready to feather the props and pull back the power and head down to the coast to fix "NOBAL" then down the coast to Aberdeen/Dyce NDB "ATF" which gives you an almost 160º turnback to runway 34. As with everthing else today I was not going to get off easily as there was another heavy crosswind approach to the airport, but by now I was pretty confident of my abilities to touch this Twotter down as smoothly as possible. Wind, it had caused me havoc today, but I had flown well and the smile on my face proved all the hard work had not been in vain.
There are four variants in the RWDesigns Twin Otter package... The standard version as flown above.
A "Float" version.
A "Ski" version with large ski's on the wheels.
And a "Tundra" large tyre version.
Summary
At its heart the DHC-6 Twin Otter is a bush pilot's aircraft. It was built in Canada for the Canadian wilderness, and that makes it a tough no nonsense sort of machine. Speed is not the issue here, getting in and out of tight areas in bad weather with passengers and cargo is what it does best. At first it is an aircraft that will take a bit of time to master, that Collins autopilot is different but interesting and also quite easy once you understand it and use it. By the time this review was completed I found how much I really like this aircraft. It has some small comparisons to the FlyJSim Dash 8 in that it is an aircraft to master to fly really, really well. But once you get there it rewards you.
As a design the Twin Otter is excellent from RWDesigns, but remember this developer is still very new to X-Plane (They also designed the A330 last year), and few areas still need some polishing. The missing COMM2/VOR2/NAV2 radio is strange when you have two COMM1/NAV1 settings with the one already in the GNS530. There are no menus and they are really required for the door operations, likewise there are no static ground objects that would go very well with the aircraft. Liveries are few, but good and some modeling work is still a bit chunky and some panels are bare and not textured, like the bulkhead behind the pilots and parts of the cabin... the wipers are a bit chunky as well.
But where it is good it very good... The panel and instruments are excellent and so is all the switchgear including the equipment designs. Overall the modeling is very good and this is certainly the quality Twin Otter we have all been waiting for. Detailing is very good and the aircraft is a challenge to fly like a professional. As an investment the Jetsim Twin Otter is a great addition to your flying career, if you like to fly around the tough areas of the world like Alaska, Africa, Northern Europe and Australia... then this aircraft is invaluable to have.
My first reaction on first seeing the Twin Otter was "wow, finally a great usable Twotter.... I love it" Now after spending sometime with the aircraft "I really love it!".... It is a great aircraft.
The de Havilland Canada DHC-6 Twin Otter -300 Series by RWDesigns is now available from the X-Plane.Org Store here :
DHC-6 Otter 300 Series and is priced at only US$27.95
Features:
High-Resolution 3D Model
3D Cockpit
Hi Res 4K textures
Full 3D exterior model
HD Night Lighting
Interchangable liveries between versions.
7 paint schemes
Custom Prop/Engine sounds
Custom Systems
Programmed Radios
Customized GNS 530
Custom airfoils and flightmodel
Custom electrical and de-Icing systems
Installation : Download is 273.70mb that is unzipped to 368.80mb. And a Serial Number is required for installation.
Documents : DHC-6 AOM (Aircraft Operating Manual) and DHC-6 Flight Tutorial
_____________________________________________________________________________________
Requirements:
X-Plane 10.30+. Windows, Mac Linux
4Gb RAM. 1Gb+ VRAM Video card
Serial Number required during installation
RWDesigns - Are the same team that brought you the A330
_____________________________________________________________________________________
Review System Specifications:
Computer System:
- 2.66 Ghz Intel Core i5 iMac 27”
- 6 Gb 1067 Mhz DDR3
- ATI Radeon HD 6970M 2048 mb
- Seagate 256gb SSD
Software:
- Mac OS Yosemite 10.10.1
- X-Plane 10 Global ver 10.35 (final)
Addons
- Saitek x52 Pro system Joystick and Throttle
- Bose - Soundlink Mini
Scenery
- EGPD Aberdeen Dyce for XP10 4.1 by anthony_d (X-Plane.Org) - Free
- EGPA Kirkwall Airport 2.3 by dkm (X-Plane.Org) - Free
- EGPB Sumburgh (sorry I can't find this original scenery?) EGPB is however included the X-Plane "Global Airports" 10.35b2
- Final Frontier version 10.2 by Tom Curtis (X-Plane Store $24.95)
X-PlaneReviews review of Tom Curtis's "Final Frontier" here: Developer Update : Final Frontier version 10.2 by Tom Curtis
telecast reacted to Stephen in Aircraft Review : DHC-6 Twin Otter - 300 Series by RWDesigns