Oh yeah, Propspanner, DEON DU PLESSIS, stirring again. Spent a bit too long in the Hassi sun??
You left out the anti-skid, autofeather, IELUs (engine parameter limiters) and ABCs (anti-yaw) by the way.
Baaaaaad Engineer. DOWN!
Well the Twin Otter does not exactly rate as the greatest looking aircraft ever designed. Looks like the nosewheel came straight off a wheel barrow. As for the high-tech wing enlarged from a cherokee 140 with it's high performance 1930 s Clark Y wing section that can't even support itself without great big struts...and even those have to be inspected on a regular basis to stop the wings falling off.
Then again, the Twin Otter can't be a bad aircraft or they wouldn't have built so many. It has a market niche that not many aircraft can compete in.
Can't say I disagree about the security van windshield comment, although the record in Algeria speaks for itself - windshields desteoyed: Let 0, Propspanners' aircraft, 2 down! Then again, a security van windshield is probably not a bad idea in Africa. Typical soviet approach to aircaft design - why put in lots of fancy, expensive curves when a flat slab of bl...dy tough glass from the parts bin will do. Some serious windshield heating in that piece of glass - 2 alternators (one backup) needed to provide the juice for windshield heating and prop de-icing.
Take the dimmer for the CWD warning lights on the LET for instance. The Americans would have used a fancy dimmer system with rheostats and photo cells - LET just used a folding smoked perspex cover to dim lights at night. Space pencil approach, but it works and doesn't break.
Rather fly behind a Walter than a PT6; they are bullet proof engines that do not have a fraction of the hot section problems of a PT6, can run on fuels that a PT6 would choke on, and a lot more economically as far as maintenance goes, at that. I figure if you could chop up a PT6 fine enough to fit in the fuel tank the Walter would run on it and spit out the soft bits.
Walter has a slightly higher fuel consumption than PT6A since it uses a slinger ring for fuel distribution instead of fuel nozzles. Then again this prevents hot spots in the hot section.
Never had a moments grief from a Walter and never had a failed start in I guess around 5000 cycles. How many replacement PT6s you looking for again, I am sure you could enlighten us Propspanner???? Walter doesn't even have a hot section inspection between overhauls - doesn't need one.
Guess that's why they re-engine the Thrush with the Walter despite the harsh environment these ag aircraft operate in.
I still reckon that it's time someone came up with a new design in this category of aircraft since the contenders are really thin on the ground - there's got to be a ready market. What other 19 seat twin turbine aircraft are there with STOL capabilities? There's the DO 228 but it 's an expensive aircraft to operate with those Garret engines. Both the Let and the Otter were designed in the 60s and airframe maintenance costs on the Otter are high.
My ideal aircraft in this category would have the following characteritics:
* STOL capabilities
* Simple yet efficient airframe of metal construction and modern design.
* Comfortable, quiet cabin with efficient airconditioning system
* Simple systems
* Light weight with OEW not greater than 35OO kg.
* Ability to carry a payload of at least 2700 kg.
* Cruise speed of at least 180 kts, preferably higher.
* Generous baggage capacity.
* Walter engines.
* Low maintenance and operational costs
* Coffee machine
* Africa proof (OK, maybe that's a bit unrealistic)
Asking a lot isn't it? However, look at how aircraft like the Cirrus SR20/22 have taken a quantum leap in aircraft design by starting with a clean sheet of paper. I reckon a DO228 derivative with Walter engines would come close. Gotta make it look a bit prettier though and something has to be done about that cabin! DO228 has a great wing though.
Let's try and keep this discussion to sensible debate instead of bringing security van discussions into the equation, my opening comments not withstanding!
ps. Why do twin Otter pilots hold handies on take off - is it that scary? I thought that the Otter Guys were really friendly until I realised they weren't waving but holding the power levers!
Last edited by wheels up; 3rd Sep 2005 at 20:23.