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#11
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CTR is right, use the flight manuals where possible, as I did. CTR is a
tilt rotor advocate (CTR stands for Civil Tilt Rotor) and he works for Bell. His coments on my presentation are fundamentally wrong, he fails to mention that the V22 also uses aux tanks for the plot I present, as well. The weight of the tanks is subtracted from both aircraft, the payloads are correct as published. The charts are backed up by the published data for each model, I will provide the source data to anyone who emails me. As shown in the presentation at the below web site, a tilt rotor carries half the payload, has no range advantage over a helicopter, and has much less transport efficiency (speed times payload) at any range.. http://webpages.charter.net/nlappos/...comparison.pdf Nick "CTR" wrote in message oups.com... Nishant, If you intend to use data you have collected over the internet to support your Mechanical Engineering Final Year Syllabus, I recommend that you stick to published data from sources like SAE, NASA or AHS. Referencing data, opinions or conclusions from individuals personal web sites is not a good idea. Do your own research of from reputable data sources and then draw your own conclusions. Good luck, CTR |
#12
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CTR is so off base, he confuses the units on the charts. The ranges shown
are all in 1050 Nautical Miles. Yes, in the presentation, aux tanks are used for both types, tilt rotors and helicopters, and their weight (payload reduction) is accounted for properly. I stand by my numbers, they are impeccable. A tilt rotor carries half the payload to the same range as a helicopter, and it has less transport efficiency, and costs twice as much for the same payload. http://webpages.charter.net/nlappos/...comparison.pdf Nick "CTR" wrote in message oups.com... For those willing to take a close look at Nick Lappos's presentation and it's referenced supporting data, please note the following: 1) The 1,050 KM range shown for the CH-53 in Nick's presentation is with additional internal and external aux tanks installed. Using only normal internal fuel tanks, the CH-53 ferry range is only 590 KM. 2) The 1,030 KM V-22 ferry range shown in Nick's presentation is actually 2 X the 515 Amphib Assault mission range. With internal ferry tanks installed the V-22 ferry range is 2,100 KM. Twice that of the CH-53. 3) The 1,150 KM ferry range shown for the MILITARY UH-60L in Nick's presentation is with four additional 230 gallon external aux tanks installed. Using only normal internal fuel tanks, the UH-60L ferry range is only 290 KM. 4) The 750 KM ferry range shown in Nick's presentation for the CIVIL BA609 is with using only current internal fuel tanks. This is almost three times the UH-60L ferry range. With internal tanks planned for the Military BA609 version, ferry range is increased to 1,000 KM. In short, for Nick's presentation, using as many internal and external aux fuel tanks as possible for the CH-53 and UH-60L is acceptable. But the use of even additional internal aux tanks on V-22 or BA609 is prohibited. So Nishant, do your own research before you draw any conclusions. Don't take anyone's opinion (even mine) until you look closely at all reliable data sources. Good luck, CTR |
#13
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Nick,
My only mistake is after a 22 hour day is typing KM instead of NM. All numbers in my post are in Nautical miles. For those wishing go know the full facts, go to: http://www.boeing.com/rotorcraft/mil...22/v22spec.htm Under V-22 RANGE you will find: Range =B7 Amphib assault, nm (km) - 515 (954) =B7 Max, self-deployment, nm (km) 2,100 (3,892) (this is a direct paste) Then for the CH-53 go to: http://www.sikorsky.com/file/popup/1,,185,00.pdf From the Load/Range chart for ferry range (0 payload) with internal and external aux fuel tanks the CH-53 range shows 1050 nm (1946 km). So if I am confused Nick, please explain why in your charts you only show the V-22 self deploy 0 payload range being approximately 1030 Nautical Miles. While the source you reference using for your data states this range to be 2100 Nautical Miles? What external aux tanks did you use for the V-22 range, since the V-22 does not carry external aux tanks? Again, I suggest no one ever use conclusions from some one's personal web site. Go to reputable sources and check the data yourselves and drow your own conclusions. Take care, CTR |
#14
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Nick said;
"Also, Stepniewski and Keys "Rotary Wing Aerodynamics" (Dover publications) has a major section on tilt rotor design aspects.' OK Nick, what chapter is missing from my copy of "Rotary Wing Aerodynamics"???? Chapter II - IV is on the Winged (compound) Helicopter. Chapter II - V is on the Tandem (fore & aft rotors) helicopter. The Tilt-rotor is covered in 45 words and a picture in Chapter I - I. As a mater of fact, Stepniewski recommends the Intermeshing configuration for tomorrow's rotorcraft. http://www.UniCopter.com/1093.html "NickL" wrote in message There are many American Helicopter Society technical papers that have been given at the AHS annual forum over the years, several at a level which would be right for undergraduate work. Ask your school librarian for help, these are usually available in a few days. Also, Stepniewski and Keys "Rotary Wing Aerodynamics" (Dover publications) has a major section on tilt rotor design aspects. Nick Lappos For some broad performance comparisons between helicopters and tilt rotors and supporting sites, see my site: http://webpages.charter.net/nlappos/Disk-Loading.pdf |
#15
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CTR, your confusion abounds:
1) The range chart I show is based on a hover at takeoff, unlike the rolling airport takeoff that you would like to claim. A mission from a ship at your takeoff weight would qualify the V22 as a submarine, BTW. My charts show flight manual mission capability, not your marketing hype. Stick to the facts, stop selling. 2) Learn your aircraft before you waste our time, the V22 must be fitted with its aux wing tip tank to make the range I depict, at a loss of payload, just like the aux tanks used in the max range for the helo. Nobody but you (in your confusion) said external. 3) As a Test Pilot for 27 years, Fellow of the AHS, Member of the SETP and Distinguished Alum of Georgia Tech, Aerospace Engineering, I sign my posts with my name, and stand behind the data as accurate. You post marketing web sites, anonymously, so where is your credibility? My point, proven = A tilt rotor carries half the payload to the same range, and has much less transport efficiency than a helicopter. Nick Lappos |
#16
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Nick,
Thank you for finaly providing actual responses to critical comments to you presentation. Perhaps now we can proceed with a constructive technical discussion of your conclusions. In response to your original post question to me "Let me ask, what qualifications do you have to be so misunderstanding of this technical data?" I responded "I have 25 years of Aerospace engineering experience on many verticle lift aircraft including the AV-8B Harrier, won multiple awards for best paper by both AHS and SAE and have seven patents in the field of aerospace technology. How about you?" Again thank you for finaly responding to my question in response. Even if it took awhile. 1) The data I reference is the same Prime Contractor data you reference at the bottom of your Load Range chart for the CH-53 and V-22 comparison: http://www.sikorsky.com/programs/stallion/stallion.html http://bellhelicopter.com/products/tiltRotor/ http://www.boeing.com/rotorcraft/mil...22/v22spec.htm So why do your accuse me of marketing and selling? Also since the V-22 data you reference states a 2100 ferry range, where do you derive the approx 1030 NM range you show? You have made it your personal quest to force the V-22 to fly the same flight profile as a conventional helicopter and bend the numbers to negate any benifits the V-22 wing affords in range and payload. Your referenced data shows the V-22 capable of a 2100 NM ferry range. With a 2100 NM ferry range there are few places on this planet that the V-22 cannot avail itself of a short rolling takeoff. And if in the real world there is a need for the V-22 to fly a 2100 NM ferry from a ship to shore, immediately after vertical takeoff and conversion to airplane mode, it can top off its fuel while still beyond the 2100 NM radius of its destination. 2) You said "Learn your aircraft before you waste our time, the V22 must be fitted with its aux wing tip tank to make the range I depict, at a loss of payload, just like the aux tanks used in the max range for the helo." This is a distortion of the facts. There are no V-22 aux fuel tanks that change the external mold line of the aircraft. Therefore they have zero effect on the V-22 drag. Also any additional INTERNAL wing tanks consist only of a bladder in the existing wing structure. To meet the CH-53 range you show you have added external tank pods that both increase drag and weigh considerably more. And while on the topic of external tanks, as an engineer, how can you compare the range of a MILITARY UH-60 with four added external 230 gallon tanks to a CIVIL BA609 operating on internal fuel only? Especially since to achieve the range you show the UH-60 has to limit itself to 4,000 ft altitude. You don't even allow the BA609 to use it's additional permanently installed fuselage tank for an additional 250 mile range. Please do not accuse me of being biased if you plan to twist data to meet your preconcieved conclusions. 3) Nick, you accused me of the following "You post marketing web sites, anonymously, so where is your credibility?" Again, I referenced the same type of sites you referenced in your presentation. And if you had bothered to take the time to check out and study the AHS link for data on the the BA609 I recommended, you would have figured out who I was a long time ago. Yes I am the primary author of this paper. Here it is again to save you some time: http://www.vtol.org/pdf/61PropulsionII.pdf Nick, if you truly believe that your presentations conlusions can withstand the scrutiny of the AHS, why don't you submit an abstract for the next forum? Finally Nick, as I said from the start: "Yes they (the V-22 supporters) twist the facts to make their case. But you also twisting the facts does not make your case stronger. It only makes it weaker" I also stick by my statements. Have fun, CTR |
#17
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CTR, I accuse you of marketing and selling because you are. The data I show
is precise, but you post inane questions because you need to show disagreement, kind of like a spin thing, huh? Please tell the group that you are a hydraulics designer for Bell, and know lots about pipes and fluid and O rings, but not a damn thing about rotorcraft performance, (as your inept observations prove) and that your heart and soul are with the tilt rotor (as they should be, but do not park your brain as you build that new machine). I have updated the presentation, and now include a US Navy payload-range chart that agrees with my work, precisely. No facts twisted, not even bent a little. Eat it and weep, CTR. Regarding the 2100 miles of ferry range, for the FIFTH time I will tell you that cannot be done from a transport ship, is not possible for a normal troop carrying mission (which is what I am comparing) and has zero payload when flown. It is not germain, but it has one virtue for you - it has a big number, a really big number, and that seems to stick in your brain. As I have posted to each of your inept comments, the V22 cannot take off from a ship with the ferry fuel to go beyond the 1100 miles I have shown. The 2100 miles is a ferry stunt, troopless and unable to be done from an assault transport. Deal with it. Regarding the difference between a 609's takeoff payload and the size of a fuel tank, suffice it to say that the aircraft must actually take off with the fuel for it to be used in the mission, a fact that seems to escape you. The 609's range shown is from a hover, and is all it can do because its hover performance is so poor. Short of burning its wings and crew for fuel, its range is stuck at the 700 miles shown. Do not try to understand this, it is a heavy concept. A tilt rotor carries half the payload of a helicopter, to the same range, and has much less productivity. http://webpages.charter.net/nlappos/...comparison.pdf Your hydraulics background explains your confusion about hover payload and how it limits mission range. Airplanes use more runway when they get heavier, but they take off. Helos make a big splash in the water if they are loaded beyond their hover weight. Think hard about that, grasshopper. Nick PS I have 16 patents, and have authored over 20 papers, as well as several AGARD and NASA TR's, and am a Fellow of that AHS you describe, for contributions to understanding helicopter tactical maneuverability and performance. AND I can read a payload-range chart, something you might learn to do if you try real, real hard. AND I sign my name to my work, and do not hide behind a fictious username. "CTR" wrote in message ups.com... Nick, Thank you for finaly providing actual responses to critical comments to you presentation. Perhaps now we can proceed with a constructive technical discussion of your conclusions. In response to your original post question to me "Let me ask, what qualifications do you have to be so misunderstanding of this technical data?" I responded "I have 25 years of Aerospace engineering experience on many verticle lift aircraft including the AV-8B Harrier, won multiple awards for best paper by both AHS and SAE and have seven patents in the field of aerospace technology. How about you?" Again thank you for finaly responding to my question in response. Even if it took awhile. 1) The data I reference is the same Prime Contractor data you reference at the bottom of your Load Range chart for the CH-53 and V-22 comparison: http://www.sikorsky.com/programs/stallion/stallion.html http://bellhelicopter.com/products/tiltRotor/ http://www.boeing.com/rotorcraft/mil...22/v22spec.htm So why do your accuse me of marketing and selling? Also since the V-22 data you reference states a 2100 ferry range, where do you derive the approx 1030 NM range you show? You have made it your personal quest to force the V-22 to fly the same flight profile as a conventional helicopter and bend the numbers to negate any benifits the V-22 wing affords in range and payload. Your referenced data shows the V-22 capable of a 2100 NM ferry range. With a 2100 NM ferry range there are few places on this planet that the V-22 cannot avail itself of a short rolling takeoff. And if in the real world there is a need for the V-22 to fly a 2100 NM ferry from a ship to shore, immediately after vertical takeoff and conversion to airplane mode, it can top off its fuel while still beyond the 2100 NM radius of its destination. 2) You said "Learn your aircraft before you waste our time, the V22 must be fitted with its aux wing tip tank to make the range I depict, at a loss of payload, just like the aux tanks used in the max range for the helo." This is a distortion of the facts. There are no V-22 aux fuel tanks that change the external mold line of the aircraft. Therefore they have zero effect on the V-22 drag. Also any additional INTERNAL wing tanks consist only of a bladder in the existing wing structure. To meet the CH-53 range you show you have added external tank pods that both increase drag and weigh considerably more. And while on the topic of external tanks, as an engineer, how can you compare the range of a MILITARY UH-60 with four added external 230 gallon tanks to a CIVIL BA609 operating on internal fuel only? Especially since to achieve the range you show the UH-60 has to limit itself to 4,000 ft altitude. You don't even allow the BA609 to use it's additional permanently installed fuselage tank for an additional 250 mile range. Please do not accuse me of being biased if you plan to twist data to meet your preconcieved conclusions. 3) Nick, you accused me of the following "You post marketing web sites, anonymously, so where is your credibility?" Again, I referenced the same type of sites you referenced in your presentation. And if you had bothered to take the time to check out and study the AHS link for data on the the BA609 I recommended, you would have figured out who I was a long time ago. Yes I am the primary author of this paper. Here it is again to save you some time: http://www.vtol.org/pdf/61PropulsionII.pdf Nick, if you truly believe that your presentations conlusions can withstand the scrutiny of the AHS, why don't you submit an abstract for the next forum? Finally Nick, as I said from the start: "Yes they (the V-22 supporters) twist the facts to make their case. But you also twisting the facts does not make your case stronger. It only makes it weaker" I also stick by my statements. Have fun, CTR |
#18
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OOPS, I couldn't find my copy (still in cartons in the garage, after my move
South) so I THOUGHT I remembered a chapter on it. Oh well, sorry about that. Nick "Dave Jackson" wrote in message news:sey1f.114567$tl2.98843@pd7tw3no... Nick said; "Also, Stepniewski and Keys "Rotary Wing Aerodynamics" (Dover publications) has a major section on tilt rotor design aspects.' OK Nick, what chapter is missing from my copy of "Rotary Wing Aerodynamics"???? Chapter II - IV is on the Winged (compound) Helicopter. Chapter II - V is on the Tandem (fore & aft rotors) helicopter. The Tilt-rotor is covered in 45 words and a picture in Chapter I - I. As a mater of fact, Stepniewski recommends the Intermeshing configuration for tomorrow's rotorcraft. http://www.UniCopter.com/1093.html "NickL" wrote in message There are many American Helicopter Society technical papers that have been given at the AHS annual forum over the years, several at a level which would be right for undergraduate work. Ask your school librarian for help, these are usually available in a few days. Also, Stepniewski and Keys "Rotary Wing Aerodynamics" (Dover publications) has a major section on tilt rotor design aspects. Nick Lappos For some broad performance comparisons between helicopters and tilt rotors and supporting sites, see my site: http://webpages.charter.net/nlappos/Disk-Loading.pdf |
#19
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Nick,
I thought arrogance was limited to fast mover pilots. Most of the helo pilots have worked with actually answer questions instead of degrading the people asking them. So why don't we try this again. And instead questioning the capabilities of the questioner, answer the questions: And to keep it specific and to the point, one question at a time. Lets start with a straight forward one. You use 750 NM 0 load range for the BA609. However the site you reference in your presentation notes that the aircraft is can be fitted with an additional internal tank to provide 1000 NM total range. Why don't you use this 1000 NM range? Carlos A. Fenny AKA Civil Tilt Rotor Note: In 29 years I have worked, hydraulics, mechanical controls, landing gear, flight test, canopy/escape systems, composite structure and advanced design. |
#20
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CTR,
You ask, "..the aircraft is can be fitted with an additional internal tank to provide 1000 NM total range. Why don't you use this 1000 NM range?" As I have said now SIX times, the 609 cannot hover with that fuel and tank, even when it has zero pax or payload. The hover weight is rigidly limited by the rotor performance. With all the power the 609 has, it can only hover with enough fuel to go 750 NM, leaving all passengers home. THAT IS WHAT THE PAYLOAD RANGE CHART IS FOR, to tell you how to make the tradeoff between fuel and payload, at a fixed hover takeoff condition. You are clearly one of those guys who thinks a rotorcraft is like your car, fill the trunk, fill the seats and fill the gas tank. That is not how we can operate. The 609 can hover at 16,800 lbs, not one pound more. Its empty weight is 11,300 lbs, then it must carry no more than 5500 lbs of fuel when it starts its journey. In cruise, the 609 needs about 7.4 lbs of gas to go one mile. Therefore, it goes about 750NM with no pax. If we add one pax, we take out 170 lbs of gas, and its range drops by 23 NM. Get the picture? Now, if you are at an airport and want to allow rolling takeoffs, and load the aircraft up until it cannot hover, that is fine, but don't try that at Wall St heliport, the sound of proprotors cutting light poles is offensive to the neighbors. Don't try that off an assault transport, the marines in back do not have water wings. If the tilt rotor cannot hover at the start of its mission, it cannot do the mission. Rotorcraft missions need rotorcraft performance, thus we publish the performance with a hover at the start, so that we can take off from small places, the reason why folks buy our machines. Get the picture? Tilt rotors carry half the payload to the same range as helos, and cost twice as much per ton of payload to do it. Nick "CTR" wrote in message oups.com... Nick, I thought arrogance was limited to fast mover pilots. Most of the helo pilots have worked with actually answer questions instead of degrading the people asking them. So why don't we try this again. And instead questioning the capabilities of the questioner, answer the questions: And to keep it specific and to the point, one question at a time. Lets start with a straight forward one. You use 750 NM 0 load range for the BA609. However the site you reference in your presentation notes that the aircraft is can be fitted with an additional internal tank to provide 1000 NM total range. Why don't you use this 1000 NM range? Carlos A. Fenny AKA Civil Tilt Rotor Note: In 29 years I have worked, hydraulics, mechanical controls, landing gear, flight test, canopy/escape systems, composite structure and advanced design. |
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