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[i][During training, Pete and the other commanders flew the Lunar Landing Training Vehicle, or LLTV - and a similar, predecessor called the Lunar Landing Reserach Vehicle or LLRV - and, of course, 'flew' numerous landing simulations in immobile simulators on the ground. The LLRV/LLTV - or The Flying Bedstead, as it was sometimes called - was built for NASA by Bell Aerosystems, Buffalo, NY and consisted of an open frame that supported a large, down-pointing jet engine that removed 5/6th of the effective vehicle weight and allowed the pilot then to use the equivalent of the Descent engine and RCS thrusters to practice landings. The accompanying photo shows Pete flying the LLTV.] [I asked Pete about the value of this training.] [Conrad - "I think everybody agreed that the LLTV was very essential to a successful landing. One of the problems which we were talking about earlier at lunch is that you have to realize that the visual on the simulator was very bad. We had a plaster-of-paris lunar surface (called the L&A) and a B&W television camera (that flew to it). So you're looking at a flat, no-depth boob tube - a television - in the window. So, the last five hundred feet, if you were watching that out the window in the simulator, it wasn't any good. It just didn't really resemble the real world."] [Bean - "It was a virtual image something or other. Which was a flat TV with some optics that..."] [Conrad - "Tried to give it depth..."] [Bean - "But it didn't."] [Conrad - "It was the best they had at the time. We didn't have a moving-base simulator, either. (In more recent times, Shuttle crews have been able to train in simulators that move in response to crew inputs and, thereby, give much more realistic simulations.) So, the LLTV was critical, to get a real feel. And the reason Al made the comment about maneuvering at 110:31:06 is that the LMPs didn't fly the LLTV."] [NASA built two LLRVs and three LLTVs. Three of these five vehicles were lost in accidents. Because of the jet engine, the LLTV was actually a less stable vehicle than the LM and, therefore, was harder to fly. For this and other reasons, it was decided that only people who absolutely needed the experience - mission commanders and their backups - would fly the LLTV. None of the LMPs ever flew one.] [Conrad - "Al hadn't flown one, and that's why he made the remark (110:31:06) when I started really maneuvering the thing around. Because you had big attitude changes up there, because you're in a low gravity field. He had seen that kind of a maneuver, probably, inside the simulator. But that virtual image display and the fixed base didn't really give you any feel for it. So, the first time Al really experienced that was at the Moon. And I just passed it off 'Yeah, I'm busy doing what I was doing.'!"] [Bean - "We were all flying helicopters and you didn't maneuver a helicopter any where near like that. Up there, you really had to move the LM to maneuver it. So Pete got used to it and I was thinking helicopter kind of stuff. So, when you (Pete) suddenly maneuvered much more than a helicopter, it caught me by surprise. But to you, well, that's the way you do it. I think it's because, on Earth, you're supporting the weight with a certain amount of thrust. So, let's say you've got to knock off ten foot per second forward. You pitch up (means tilt the LM back and, therefore, the direction of thrust up) to a certain angle to do that and you get used to that kind of maneuver. You go on to the Moon; you've got one sixth the thrust to hold this same mass up and ten feet per second forward with that mass is the same as it was on Earth. But, in order to stop it (meaning slow it down by ten feet per second) with one-sixth the thrust, you're going to have to pitch up (means tilt the LM back) a lot harder. So I think it's just strictly the fact that you're operating with less thrust than a helicopter for the same weight and the same momentum. So, in order to use it, you've got to get that thrust vector up higher faster or you're just never going to slow down the translations - or get one going and then stop it. When you think about it, it makes sense. But, at the time, it just seemed like 'God, what's he doing?' It felt to me like you were pitched too far (back), you know. And you probably were doing quite a bit because you've got to get it (pitched) up there to get the little ol' thrust vector to work."] [Conrad - "That's right, you have to move it more to get the maneuver. So it looks really bad to you, although nothing serious is happening."] [Bean - "It looked normal to you!"] [Conrad, from the 1969 Technical Debrief - "I think the manual control of the LM was excellent. The LLTV is an excellent training vehicle for the final phases. I think it's almost essential. I feel it really gave me the confidence that I needed. I think the (immobile) simulator did an excellent job in manual control and LPD training all the way down to the last couple of hundred feet. I think both devices worked very well together."][/i]
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