A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Bygrave and Chichester
From: Tom Sult
Date: 2009 Aug 02, 16:38 -0500
From: Tom Sult
Date: 2009 Aug 02, 16:38 -0500
I agree with what you have said but the crash data for 336/337 is no better than other twins. Thomas A. Sult, MD IntegraCare Clinic www.icareclinics.com firstname.lastname@example.org On Aug 2, 2009, at 3:58 PM, Greg R. wrote: > > Not to speak for Gary, but the pusher/puller configuration has > what's called > "centerline thrust" - i.e. if you lose an engine, the thrust vector > stays on > the centerline - theoretically making the engine-out procedure > easier to > handle (ditto for a single-engine, though the engine-out procedure > is a lot > more cut-and-dried... ;-)). > > Wing-mounted twins have a more-complicated engine-out procedure - > not only > identifying the dead engine, securing/feathering it (also true of > centerline-mounted engine configs), but also maintaining a slight > bank angle > to compensate for the thrust imbalance caused by the dead engine. > > http://en.wikipedia.org/wiki/Critical_engine > > Not sure if the Vmc (minimum-controllable velocity) restrictions > would apply > to A/C with centerline-mounted engines, that's probably a question > for Gary. > > -- > GregR > > > ----- Original Message ----- > From: "Greg Rudzinski"
> To: "NavList" > Sent: Sunday, August 02, 2009 12:16 PM > Subject: [NavList 9297] Re: Bygrave and Chichester > > > > Gary, > > How would the Cessna 336/337 perform if one engine fails? Is there an > advantage to a pusher puller configuration over a single or wing > mounted twins? > > Greg > > On Aug 2, 11:18 am, Gary LaPook wrote: >> Well, I would agree with you Douglas, as judged from our >> perspective in >> 2009, that Chichester may have been "reckless." But as judged from >> the >> standards of aviation pioneers almost 80 years ago, I prefer the word >> "bold." If you look at early pioneering efforts, Lindberg, Perry, Sir >> John Franklin, Columbus etc., they all appear reckless as viewed >> through >> our prism of time. But that is what pioneering is all about, taking > chances. >> >> Regarding you preference for twin engine flying, the accident >> statistics >> show that they are more dangerous than singles, pretty >> counter-intuitive. Flying a twin when both engines are operating is >> just >> like flying a single, it only gets interesting when one quits. Then >> the >> pilot must deal with a greatly reduced performance envelope and >> asymmetric thrust causing control difficulties. If the pilot >> doesn't do >> everything exactly right he ends up crashing and the crash happens >> at a >> higher speed than would have occurred in a single. By US >> certification >> standards (I expect they are similar in Britain) a single must have a >> stall speed below 60 knots while a twin can have a much higher speed. >> This means that a pilot trying to crash land a twin must fly above >> the >> stall speed resulting in a higher impact speed and much more kinetic >> energy to dissipate (varies with velocity squared), can we say "torn >> aluminum" and "mangled bodies?" I've litigated airplane crashes for >> the >> last twenty years and I have seen my share of bent aluminum and >> autopsy >> photos. (BTW, a Cessna 310 Twin fits in a box on a standard pallet, >> about five feet square and three feet deep after it impacts the dirt. >> Airplanes are mostly air surrounded by an aluminum skin, just like an >> empty beer can and they squish just like a beer can..) >> >> After the loss of one engine the airplane has little or no climb >> capability. It will only climb or maintain altitude if the pilot does >> everything right. If he doesn't get rid or the drag form the flaps, >> the >> landing gear and the windmilling propeller immediately then he is >> going >> down. >> >> I'll give you some examples. About seven years ago a Cessna 310 was >> taking off from Laverne airport just northeast of Los Angeles on July >> 4, 2002, Independence Day. One engine quit right after takeoff and >> the >> pilot did not do everything right and the plane crashed on top of a >> bunch of picnickers celebrating Independence Day in the park near the >> airport resulting in the deaths of the two occupants of the plane, >> two >> deaths of the picnickers and severe injuries for nine other people on >> the ground. See the accident report at: > http://www.ntsb.gov/ntsb/GenPDF.asp?id=LAX01FA152&rpt=fa >> >> The left propeller control was found "one inch aft." In order to >> feather >> the propeller it is necessary to pull the prop control all the way >> aft, >> about eight inches. Since the pilot did not move the prop control all >> the way aft the prop did not feather and the plane could not maintain >> altitude with the left engine windmilling creating a lot of drag. It >> turned out that the pilot had done exactly as he had been instructed. >> His instructor's technique for practicing engine out emergencies >> called >> for the student pilot to just pull the prop control back one inch to >> demonstrate that he had identified the failed engine and that he >> would >> have feathered the prop in a real emergency. But in a high stress >> situation people do what they have practiced so four dead people, >> including two little children, and nine serous injuries. >> >> Another case I worked on involved a Piper Navaho hauling sight seers >> around Hawaii. One engine packed it in and because the mechanic had >> not >> used the proper method to adjust the wastegate controller on the >> other >> engine, the remaining engine was not developing full power so the >> airplane could not maintain altitude on the one engine. So even >> though >> the pilot was doing everything right he still had to ditch in the sea >> near Hilo and one little old lady, celebrating her fortieth wedding >> anniversary, rode the plane to the bottom of the sea. See report >> at:http://www.ntsb.gov/ntsb/GenPDF.asp?id=LAX00FA310&rpt=fa >> >> Another case I worked on involved a Twin Otter powered by two Pratt & >> Whitney turboprop engines. The underground fuel tank from which the >> airplane had just been refueled was contaminated with water (it >> looked >> like mud) and one engine stopped right after the nose was raised >> due to >> ingesting the water. The pilot then did everything wrong and >> feathered >> the wrong engine, shutting down the one operating engine. This >> resulted >> in 16 deaths of the occupants. >> See:http://www.ntsb.gov/ntsb/GenPDF.asp?id=LAX93FA149&rpt=fa >> >> Having two engines gives one the sense that he has redundant >> systems and >> that it is unlikely to have two reliable systems fail at the same >> time. >> So, if an engine should fail once every 5,000 hours then the chance >> of >> two such engines failing at the same time should be only once every >> 25,000,000 (5,000 times 5,000) hours. But that assumes that the two >> systems are completely independent from each other which is rarely >> the >> case. First, obviously, both engines are being operated by the same >> pilot and any error on his part can result in the loss of both >> engines. >> Both engines received the same fuel so if one tank has contaminated >> fuel >> they both do. They were refueled at the same time so if the pilot >> runs >> one out of fuel then the other will follow moments later. The same >> mechanic worked on both engine and if he screwed up one then he >> probably >> screwed up the other one too. I remember watching a Cessna 310 take >> off >> from Chicago Midway airport one day. Right after takeoff one engine >> failed and the pilot was able to bring it around and land safely. The >> plane taxied up to my hangar with one prop stopped and my friend Bill >> jumped out and walked right past me. I asked him, as he passed, >> what had >> happened and he said he couldn't stop to talk as he had to "go and >> clean >> out his shorts." I don't think he was talking figuratively since he >> went >> immediately into the men's room. The next day when I saw him I asked >> again and he said he was doing a test flight after the mechanic had >> adjusted the propeller governor and right after takeoff that one >> propeller had gone into feather uncommanded which resulted in the >> loss >> of power from that engine. As he was bringing the plane around to >> land >> he said that all he could think about was that the mechanic had just >> adjusted _both_ propeller governors and he was waiting for the >> other one >> to go into feather too. >> >> In the case of over water ferry flights on which the plane is heavily >> overloaded with fuel, the single engine ceiling may be below sea >> level. >> This means with such a heavy load that the plane cannot maintain >> altitude if just one engine fails and a ditching is inevitable. In >> this >> case a twin is quite a bit less safe than a single since with two >> engines you have twice the probability of an engine failure, 2 per >> 5,000 >> hours using my prior example. >> >> gl >> >> douglas.de...@btopenworld.com wrote: >>> My interest in the Bygrave helical slide rule too Gary, was >>> stimulated > when I read Chichester's book 'The Lonely Sea and the Sky' many > years ago. >> >>> I have been hoping ever since to find one, perhaps one of them would > turn up in an antique shop or 'car boot sale', but now realise that > fond > dream is far from ever becoming a reality. >> >>> It is very strange that they are now so incredibly rare >>> considering they > must have been made in reasonably large numbers from the early > 1920's up to > the mid 1930's, and were also an official piece of navigating 'kit' > for > aircraft navigators in that period for the RAF, so must have been > made in > fairly large numbers rather than just a relatively few for > experimental > purposes. They were also available to buy privately. So what > happened to > them all? It's most odd. >>> Even the most arcane scientific apparatus and instruments are >>> usually > preserved or survive in private hands to be sold on or given away to > others > rather than just binned. >> >>> Are all those RAF Bygrave slide rules still locked away in some old, > musty, forgotten RAF or government store at the back of dusty shelves > awaiting some storekeeper to find them and be told to put them in an > auction > of ex-government surplus. (Still dreaming you see !). >> >>> Whilst the skill and amazing endeavour of what Chichester achieved >>> is > not to be denied an any way, (and you have now confirmed by your own > practical flying test in a Tiger Moth); which was immediately > apparent to me > when I read of the exploit, and it has continued to amaze me still - > with > what he wrote I was also filled with the astonishment and feelings > that > Chichester was idiotically reckless in what he did,..(I think) to > the point > of insanity. >> >>> Given that he writes in a style which is deliberately meant to >>> make his > story not just interesting but no doubt boost his (Chichester's) > reputation, > and sales of the book, and hopefully have the reader clutching the > book with > white knuckles in anticipation of events unfolding; nevertheless, he > exposes > a devil-may-care attitude of quite serious stupidity and ignores > issues of > high importance which any right-thinking person would not consider > reasonable, and certainly not anyone who knows anything about flying > and the > consequences involved in flying solo in a single engined aitrcraft > with a > 'dodgy' engine over large stretches of water. >>> ---------- >> >>> I had a personal friend who taught me to fly, he was the Chief >>> Flying > Instructor at Bembridge flying school, and who very nearly lost his > life > when the donkey of the Cessna 150 stopped en route, mid - Solent, as > he was > flying back to Bembridge from Goodwood, (The Solent is the sea - > only four > miles of water between the Isle of Wight and the mainland) -and after > turning downwind towards the mainland to maximise his ground > traverse, he > did not make it and was... >> >> read more � > > > > > --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To unsubscribe, email NavListemail@example.com -~----------~----~----~----~------~----~------~--~---