Bob Llewellyn Posted May 19, 2014 Share Posted May 19, 2014 Cri Cri's have a fairly high stall speed. Doesn't that rule them out for RAAus?.Comparo ( I 914 to 2 503's ... 1 x 924 x4 strokes = 3896. ( 2 x 503 x2 strokes. = 2012 . The 914 wins easily.. Any other comparisons you want me to do? Very small charge... Nev So, the 503s are definitely the cheaper solution - glad you agree! Hey, the Short Scion used a pair of Pobjoy Niagaras, and look at its load factor... Link to comment Share on other sites More sharing options...
facthunter Posted May 19, 2014 Share Posted May 19, 2014 The Comper Swift used ONE .(Originally as most had other s fitted later) Didn't the DH Dragon Have one of the biggest payload / HP ? 2 x 130 HP Gypsy 1-c's. Talking of Payload etc I recall an airline at Tullamarine . They taxi out in their brand new Short Skyvan. Tower says/ What Plane is THAT?. Skipper(proudly) THAT is our brand new SKYVAN. Tower .. Haven't you unpacked it yet? ... Nev 1 Link to comment Share on other sites More sharing options...
Bob Llewellyn Posted May 19, 2014 Share Posted May 19, 2014 The Comper Swift used ONE .(Originally as most had other s fitted later) Didn't the DH Dragon Have one of the biggest payload / HP ? 2 x 130 HP Gypsy 1-c's.Talking of Payload etc I recall an airline at Tullamarine . They taxi out in their brand new Short Skyvan. Tower says/ What Plane is THAT?. Skipper(proudly) THAT is our brand new SKYVAN. Tower .. Haven't you unpacked it yet? ... Nev The Scion also had, from memory, a 10-seat configuration. The point I was trying to make is that twin engines increase safety, especially when flying over tiger country, provided the aeroplane isn't loaded so heavily that the engine-out handling is razor-edged. Link to comment Share on other sites More sharing options...
facthunter Posted May 19, 2014 Share Posted May 19, 2014 You would have to be asleep to have a control problem with a twin and engine failure in cruise. You will have to get lower straight away in a Jet, as you lack the power to stay where you are. but you still don't have an assymetry problem of any magnitude. Where you get into strife is getting too slow so the rudder loses the effectiveness to keep the plane from yawing. Below VMC (a). This is most critical on initial climb out, where the performance may be very marginal as to climb gradient or if the approach is misjudged, and you get low and slow, then . Nev 1 Link to comment Share on other sites More sharing options...
Bob Llewellyn Posted May 20, 2014 Share Posted May 20, 2014 You would have to be asleep to have a control problem with a twin and engine failure in cruise. You will have to get lower straight away in a Jet, as you lack the power to stay where you are. but you still don't have an assymetry problem of any magnitude. Where you get into strife is getting too slow so the rudder loses the effectiveness to keep the plane from yawing. Below VMC (a).This is most critical on initial climb out, where the performance may be very marginal as to climb gradient or if the approach is misjudged, and you get low and slow, then . Nev Piper Apache 150? Link to comment Share on other sites More sharing options...
Bob Llewellyn Posted May 20, 2014 Share Posted May 20, 2014 You would have to be asleep to have a control problem with a twin and engine failure in cruise. You will have to get lower straight away in a Jet, as you lack the power to stay where you are. but you still don't have an assymetry problem of any magnitude. Where you get into strife is getting too slow so the rudder loses the effectiveness to keep the plane from yawing. Below VMC (a).This is most critical on initial climb out, where the performance may be very marginal as to climb gradient or if the approach is misjudged, and you get low and slow, then . Nev Indeed - so why not have recreational twins? Link to comment Share on other sites More sharing options...
Guest ozzie Posted May 20, 2014 Share Posted May 20, 2014 Indeed - so why not have recreational twins? Cause they get into enough sh*t as it is with singles. Link to comment Share on other sites More sharing options...
Bob Llewellyn Posted May 20, 2014 Share Posted May 20, 2014 Cause they get into enough sh*t as it is with singles. how 'bout a 12-engined seaplane!!! Link to comment Share on other sites More sharing options...
Pilot Pete Posted May 21, 2014 Share Posted May 21, 2014 I think the cri-cri needs about an extra MTR of wing length to get the wing area right Link to comment Share on other sites More sharing options...
facthunter Posted May 21, 2014 Share Posted May 21, 2014 You could design a twin that was pretty docile to manage. Contra rotating props close together and angled thrust line and large fin/rudder. Conceptually it is unlikely to fly well on one engine as few ultralights are overpowered.. You would have to have a lot of surplus power to fly with one engine stopped and the prop not feathered. Electric might offer possibilities. But then electric should be very reliable. Many early twins didn't perform well on one engine. They just extend the glide. When you can maintain level flight on one,it does aid safety, but a lot of people died training on twins and they still catch people who are not current with their assy. handling. Nev Link to comment Share on other sites More sharing options...
Teckair Posted May 21, 2014 Share Posted May 21, 2014 Yep Whyalla Airlines had a Piper Chieftain lose power on one engine, the pilot tried to continue the flight from Adelaide to Whyalla on the engine still running but it failed due to the extra load and the plane ended up in Spencer Gulf. All eight people on board died including two of my old school friends. The sad part was when the first engine quit the aircraft was over York Peninsular and could have been landed safely, but due to various pressures the pilot felt compelled to continue on to Whyalla. Link to comment Share on other sites More sharing options...
David Isaac Posted May 21, 2014 Share Posted May 21, 2014 Sorry to hear you lost two old friends in that one Richard. They shut them down as a result of that accident didn't they? Link to comment Share on other sites More sharing options...
facthunter Posted May 21, 2014 Share Posted May 21, 2014 There were some crankshaft faults.. It's normal to land at the nearest SUITABLE aerodrome with a twin. Nev Link to comment Share on other sites More sharing options...
Teckair Posted May 21, 2014 Share Posted May 21, 2014 Sorry to hear you lost two old friends in that one Richard. They shut them down as a result of that accident didn't they? Yes they did get shut down but it should have been so much more than that, it was all about money and convenience above safety. Link to comment Share on other sites More sharing options...
Teckair Posted May 21, 2014 Share Posted May 21, 2014 There were some crankshaft faults.. It's normal to land at the nearest SUITABLE aerodrome with a twin. Nev I have not checked for myself but was told there were three suitable aerodromes where they could have landed on York Peninsular. Link to comment Share on other sites More sharing options...
facthunter Posted May 21, 2014 Share Posted May 21, 2014 That may well be, but they are all dead now. I think the mainbearing shells moved in the tunnels and scratched the radius's causing shaft failures. It's all on record. Some think the pilot and company were given a hard time by the authority, but they went out of business, I think. There is a bit about the engine faults concerning the maker. There is always something to get from reading about these happenings. IF there are indications the engine is not right, (noises vibrations loss of power, oil pressure etc) get it on the ground. If you are on fire do it even more quickly. Nev Link to comment Share on other sites More sharing options...
Bob Llewellyn Posted May 21, 2014 Share Posted May 21, 2014 That may well be, but they are all dead now. I think the mainbearing shells moved in the tunnels and scratched the radius's causing shaft failures. It's all on record. Some think the pilot and company were given a hard time by the authority, but they went out of business, I think. There is a bit about the engine faults concerning the maker. There is always something to get from reading about these happenings. IF there are indications the engine is not right, (noises vibrations loss of power, oil pressure etc) get it on the ground. If you are on fire do it even more quickly. Nev go the Do-X. Or even the dreaded 7-engine approach in a B52? with one out... surely a fire will get you to the ground quickly, one way or another? Link to comment Share on other sites More sharing options...
Gnarly Gnu Posted May 21, 2014 Share Posted May 21, 2014 Yes they did get shut down but it should have been so much more than that, it was all about money and convenience above safety. I understand they were wrongly shut down by CASA but fortunately were able to recover substantial damages against CASA later. I say fortunate but we are paying for these stuff-ups, it would be so much better if they didn't act like some doofus totalitarian thugs from the start. Lycoming were shady too, they always admit to nothing & then quietly issue AD's shortly after. 1 Link to comment Share on other sites More sharing options...
facthunter Posted May 21, 2014 Share Posted May 21, 2014 Like the Viscount going to Winton in the 60's The wing failed due to the heat of a Magnesium fire in one of the engines. ( Another "stalled" post) it should have been there a half hour ago. I think my computer goes to sleep Nev 1 Link to comment Share on other sites More sharing options...
Teckair Posted May 22, 2014 Share Posted May 22, 2014 Some think the pilot and company were given a hard time by the authority, I understand they were wrongly shut down by CASA WTH Link to comment Share on other sites More sharing options...
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