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Too much fun.. almost..
Wow, sounds like such a great day! Congrats Kevin! :-)
Isn't it wonderful when everything comes together? Ok, so you had a sloppy one. The important part is that you reacted properly and didn't bend the bird. It's all part of the learning experience. Question: Maybe I'm reading you too literally but, are you going to have to get through your 10 hrs of solo time "before" you start the x-country time? I would think that you could do a lot of that concurrently. Take care & Fly Safe, Steve R. "The OTHER Kevin in San Diego" skiddz *AT* adelphia *DOT* net wrote in message ... Got in another hop today, with some solo time tossed in for good measure.. Was supposed to fly yesterday, but the aux fuel gauge went batty on the flight before mine. It was nice to get a call from the school letting me know before I took the drive down. Unfortunately, I was informed this morning the ship was ready to go by the time I was supposed to fly. Minor procedural goof with the school. No big deal as far as I'm concerned - I got some things done around the house and actually got some work done. Weather here in the Golden State has been crappy of late and I woke up to a bit of rain. I wasn't too concerned because the outlook showed it would be cool and cloudy today, with rain beginning tonight. Looking outside right now you wouldn't expect rain but I digress.. Got to the field and worked out my W&B for both dual and solo flight. I wasn't aware I'd be going solo today, but I knew that paperwork would be required if I did. I knew the CG would be different without 150lbs of human next to me, but wow! What a difference both laterally and longitudinally.. Preflight went ok, but I thought the lower swashplate was a bit "jiggly". I hadn't flown this particular ship in about a month so had Q check it out before we launched. He said it was ok so I strapped in and got it started up. Slight issue with the left mag check - the right mag showed the expected drop but when I went to both and then back to left, the RPM took a good 10 seconds to drop and then it didn't drop half what I was expecting. Back to both and back to left and it did what it was supposed to. Guess I didn't get it "in the groove" the 1st time. I got an 'attaboy" from the left seat for catching that one. Everything was in the green so I picked us up (I'm getting pretty good at those with two of in the ship) and headed for the taxiway as I made my initial call. We were cleared for takeoff so I taxied to the runway centerline, made a right pedal turn, checked the gauges and we were off. Nice cool day with DA about 150' below actual field elevation so there was power a plenty and it didn't take but 21inches to get us outta there.. 1st approach was a little ugly, but I hadn't flown this particular pattern more than once or twice before so didn't know how I had to be set up for each leg. 2nd time around was pretty good and didn't require much fiddling on final. Q asked me to set down and pick up a couple times then asked the tower to head back to the parking area. I wasn't sure if I'd done something wrong or if Q had noticed anything with the helo.. We got back to the ramp and he set the ship down and asked "You want both doors or just the left one?" I opted for the left one only and he trotted to the hangar to pick up my logbook and the door. I sat there on the ramp, throttle at idle and watched one of the new students going over a preflight with an instructor. I couldn't help but puff out my chest a bit whenever he'd glance over at me. Pilots ego already? At 24 hours?? What a dork I am.. Good thing there was a helicopter to deflate my head a bit... Q got back with the door and my log book and in a couple minutes he was leaning in the helo and telling me what I could and could not do. Basically, I couldn't do jack. What I could do was hover, fly patterns and approaches and have fun. Ok, not much leeway but what the hell? I get to fly a helicopter all by myself again. Remember the pilot ego? Detonated like a nuclear bomb on the 1st pickup. I was all over the place for a few seconds until I figured out the balance point. Perfect situation for one of those "wanna get away" Southwest Airlines commercials.. heheh Once I was settled down, I pointed the nose towards the runway and called the tower for clearance. I had to hover at the hold short line for a min or so and then was cleared to take off so I taxied out, pointed the nose down the long direction of the runway, made my checks and I was off. Before I knew it, I was climbing out at 1000 FPM and doing 65 knots.. Before I'd even made my crosswind turning point, I had to decrease the power about 4" and add some forward cyclic to stick the altitude at 800'. Turned downwind and made my downwind checks.. Abeam my landing spot I set up my descent and got slowed down before turning base. Slowed down a bit more and was at about 45 kts and 300' AGL as I turned final. Got the angle set up and was bit high so I lowered the collective a bit more and stole a glance at the panel. Wow.. 10 whopping inches of MAP and I'm comin' downhill at a steady 300fpm. The ship started to rumble a bit about halfway down so I started adding power slowly and adding a smidge of forward cyclic.. I came up a bit short, but otherwise I felt the approach was a good one. Very little to do on the way down but ride it down. Just have to adjust my final turn numbers a bit. Went around again and this time it was much better. I turned final a little higher and faster and once I'd got the pitch angle established, it was a matter of collective and pedal until about 50' when I had to start adding forward cyclic as power was pulled.. About 10' the nose suddenly swung to the right and it took a healthy measure of left pedal to get it squared away. I thought I was just late adding left pedal as I pulled power, but found out on the next approach it was actually the wind coming from between two hangars. The third one was pretty. I hit my numbers all the way around the pattern and don't think I made a single adjustment to the cyclic on final. I ended up in a 3' hover right over the spot I was aiming for and went ahead and set it down. I called the tower and told 'em I wanted to hang out at the numbers and do some hover work. I was cleared and proceeded to work on pickups and set downs. I'm still not used to the tail down attitude these little dragonflies get when flying solo so the first few pickups were ugly to say the least. Set downs, on the other hand, are pretty much cake and I started making up games for myself to test my hovering skills. I'd hover taxi away from the numbers, turn around and pick one small spot to set down on and see how accurate I could be. Even in that last foot or so where I'd had so much trouble in the past was smooth. It got to the point where I was putting the wheel attachment point within just a few inches of where I wanted it and I was able to put the tip of the right skid right on the tip of the arrows leading to the displaced threshold several times. I tried some sideways hovering and managed to get it moving left pretty good, but right was a little erratic.. I had a hard time keeping the centerline right under my butt going that way.. Still, it was good practice. I noticed the CHT creeping up a bit so called the tower and asked to enter the pattern again. I was cleared after a few moments and off I went. Damn near busted the 800' pattern altitude 'cuz I was a bit slow in reducing power and got to my downwind checks. Everything was cool so I checked the clock to see how I was doing on time. 20 minutes before I had to head back to the ramp. I thought I'd get about 3 more patterns in after this one so got set up to make my base turn and flew a pretty good steep approach. Got a little too shallow right at the end, but that was fixed with a touch more collective.. Went around again and again, made a decent approach - not great, but not too bad.. The wind that caught me by surprise at 10' was still there, but I anticipated it and as soon as I felt the nose start to move, that left pedal got jammed in and the nose hardly budged.. Once into the hover I set it down and did some quick mental calcs. Ok, about 4 minutes per circuit, I've got a little over 10 minutes before I need to head back and it look like I've got about 7 or 8 gallons of fuel left in the main and a couple gallons in the aux. I'll do one more then call it a day. I call the tower to get cleared and I'm off again.. Crosswind and downwind legs are good, but I'm a bit too fast as I turn base and too high as I turn final. I get my angle set up good and have to lower the collective a bit more to get my descent rate up as I'm too high.. As I get it back on track, the rumble starts and I decide I'm going to make it a steep approach. I start to pull power and take a peek at the VSI.. Yikes.. 400fpm and I'm getting a bit slow. I figure I'm going to have to overshoot my spot even if I add power at this point I add some power and forward cyclic.. The rate of descent doesn't seem to be slowing and I really looks like I'm dropping rapidly and the airspeed is slowly creeping up.. At about 20' up the "oh ****s!" start and the ground is coming up pretty damned fast.. I add a handful of forward cyclic and drop the collective ever so slightly and as soon as the ship stops vibrating, I pull power and just get it stopped about 2' off the ground. I set down, collect my thoughts and pick it up. At least I've figured out how to pick up the ship solo without it wandering all over the place. I'm still uncomfortable with the "wheelie" liftoff.. I'd kinda like someone to take a video of me picking up solo so I can see how close to the ground the tail rotor is actually coming. I call tower and request a taxi back to the ramp and just as I turn around, I see Q standing near the fuel shack. Not sure if he'd just visited the soda machine or he was coming to see where I was. I was hoping he hadn't seen that last approach. If he did, there was no indication of it because as soon as I started down the runway towards the ramp, he turned and walked to the hangar. I taxied back and made a nice set down right in the center of the pad. throttled down, flicked the governor off and set the cool down timer and thought about that last few seconds of the last approach.. I'm not sure I actually got into settling with power and am thinking that I probably was just too slow adding power on final as the 1st part looked and felt pretty good. Either way, it was a really crappy way to get a helicopter back to Mother Earth and it definitely got my attention in a big way. Other than that approach, I thought I flew pretty good and looking back, I'm pleased I was able to execute a recovery for whatever the hell it was I'd got myself in to and not bend up a helicopter. Can't say the same for my ego though. Probably a damned good lesson in any case. Got the ship shut down and secured and can't help giving the ship a pat on the canopy and uttering "good girl". As I round the nose and start my walk back to the hangar, I see Q walking out towards me and I meet him halfway. "How'd it go?" "Did you see that last approach?" "I wasn't watching you.." "Good. I scared the crap out of myself." I went on to explain what happened and he kinda grinned and asked "Got into a little settling with power didja?" I had to admit that I probably had and told him what I'd done to get out of it. Q just smiled and walked away. Ok, I guess I did the right thing. I hit the "pilots lounge" and made two entries in my log book. 0.3 dual and 0.9 solo.. Q came up and asked how much time I logged and then told me he wanted be to blow through my next ten hours of solo so we could work on cross countries and asked me where I wanted to go. What a baited question.. I'd really like to fly over my mom's house and drop water balloons but I don't think the FAA would like that too much. I told Q I'd like to fly out over the desert and buzz the lizards and he said "Yeah, I'd like to do that too. Plan it out.." Cool. I'll give you one guess what I'm going to be doing later tonight.. Not sure we'll go any time soon with another storm coming through, but even if I end up flying dual in the pattern tomorrow, it'll be cool. Anytime I can get in the helicopter is great. I love this stuff! |
#2
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"The OTHER Kevin in San Diego" skiddz *AT* adelphia *DOT* net wrote in
message ... Question: Maybe I'm reading you too literally but, are you going to have to get through your 10 hrs of solo time "before" you start the x-country time? I would think that you could do a lot of that concurrently. I don't think so. It'd take me a couple weeks to knock out those 10 solo hours. Since I was tasked to create a flight plan to head to the desert, I'd imagine we're actually going to make that flight in the near future. Looking at the schedule for this morning, I see I'm scheduled for dual today. Not sure if it's going ot happen as we got some Noah's Ark style rain at 3 this morning and it's still coming down steady.. Not sure what visibility is going to be at the field, but at the least, I can hit the cafe and get some breakfast and get some informal one on one ground.. That sounds about right to me too. What I remember from my fixed wing training is that we did a duel x-country first. I'd imagine that's what your flight plan assignment is about. I was then signed off for 2 or 3 short solo x-countries with remedial training in between. I then did my long x-country. Back then, that one had to be 3 legs, each at least 100 nm's long. The regs have changed since then, from what I understand so it's a little different these days for the student plank fliers. I'm not up on what the regs require of rotorcraft students. The end result was that I finished my required x-country time with only an hour or so of solo time to wrap up and it all came together very close to the 40 hour minimum for a private pilot ticket. I hope the timing in your training works out as well! Looking forward to reading about your first x-country adventure. How do you fly a helicopter and manipulate a sectional at the same time anyway? ;-) Fly Safe, Steve R. |
#3
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A great work of story telling there, Kevin. I really enjoy reading
these. Maybe that could be your second hobby/love(?) You must have one great memory for detail. I couldn't describe the happenings of the Gravitron at the state fair with the detail you show in these posts. Keep up the good work! ref The OTHER Kevin in San Diego wrote: Got in another hop today, with some solo time tossed in for good measure.. Was supposed to fly yesterday, but the aux fuel gauge went batty on the flight before mine. It was nice to get a call from the school letting me know before I took the drive down. Unfortunately, I was informed this morning the ship was ready to go by the time I was supposed to fly. Minor procedural goof with the school. No big deal as far as I'm concerned - I got some things done around the house and actually got some work done. Weather here in the Golden State has been crappy of late and I woke up to a bit of rain. I wasn't too concerned because the outlook showed it would be cool and cloudy today, with rain beginning tonight. Looking outside right now you wouldn't expect rain but I digress.. Got to the field and worked out my W&B for both dual and solo flight. I wasn't aware I'd be going solo today, but I knew that paperwork would be required if I did. I knew the CG would be different without 150lbs of human next to me, but wow! What a difference both laterally and longitudinally.. Preflight went ok, but I thought the lower swashplate was a bit "jiggly". I hadn't flown this particular ship in about a month so had Q check it out before we launched. He said it was ok so I strapped in and got it started up. Slight issue with the left mag check - the right mag showed the expected drop but when I went to both and then back to left, the RPM took a good 10 seconds to drop and then it didn't drop half what I was expecting. Back to both and back to left and it did what it was supposed to. Guess I didn't get it "in the groove" the 1st time. I got an 'attaboy" from the left seat for catching that one. Everything was in the green so I picked us up (I'm getting pretty good at those with two of in the ship) and headed for the taxiway as I made my initial call. We were cleared for takeoff so I taxied to the runway centerline, made a right pedal turn, checked the gauges and we were off. Nice cool day with DA about 150' below actual field elevation so there was power a plenty and it didn't take but 21inches to get us outta there.. 1st approach was a little ugly, but I hadn't flown this particular pattern more than once or twice before so didn't know how I had to be set up for each leg. 2nd time around was pretty good and didn't require much fiddling on final. Q asked me to set down and pick up a couple times then asked the tower to head back to the parking area. I wasn't sure if I'd done something wrong or if Q had noticed anything with the helo.. We got back to the ramp and he set the ship down and asked "You want both doors or just the left one?" I opted for the left one only and he trotted to the hangar to pick up my logbook and the door. I sat there on the ramp, throttle at idle and watched one of the new students going over a preflight with an instructor. I couldn't help but puff out my chest a bit whenever he'd glance over at me. Pilots ego already? At 24 hours?? What a dork I am.. Good thing there was a helicopter to deflate my head a bit... Q got back with the door and my log book and in a couple minutes he was leaning in the helo and telling me what I could and could not do. Basically, I couldn't do jack. What I could do was hover, fly patterns and approaches and have fun. Ok, not much leeway but what the hell? I get to fly a helicopter all by myself again. Remember the pilot ego? Detonated like a nuclear bomb on the 1st pickup. I was all over the place for a few seconds until I figured out the balance point. Perfect situation for one of those "wanna get away" Southwest Airlines commercials.. heheh Once I was settled down, I pointed the nose towards the runway and called the tower for clearance. I had to hover at the hold short line for a min or so and then was cleared to take off so I taxied out, pointed the nose down the long direction of the runway, made my checks and I was off. Before I knew it, I was climbing out at 1000 FPM and doing 65 knots.. Before I'd even made my crosswind turning point, I had to decrease the power about 4" and add some forward cyclic to stick the altitude at 800'. Turned downwind and made my downwind checks.. Abeam my landing spot I set up my descent and got slowed down before turning base. Slowed down a bit more and was at about 45 kts and 300' AGL as I turned final. Got the angle set up and was bit high so I lowered the collective a bit more and stole a glance at the panel. Wow.. 10 whopping inches of MAP and I'm comin' downhill at a steady 300fpm. The ship started to rumble a bit about halfway down so I started adding power slowly and adding a smidge of forward cyclic.. I came up a bit short, but otherwise I felt the approach was a good one. Very little to do on the way down but ride it down. Just have to adjust my final turn numbers a bit. Went around again and this time it was much better. I turned final a little higher and faster and once I'd got the pitch angle established, it was a matter of collective and pedal until about 50' when I had to start adding forward cyclic as power was pulled.. About 10' the nose suddenly swung to the right and it took a healthy measure of left pedal to get it squared away. I thought I was just late adding left pedal as I pulled power, but found out on the next approach it was actually the wind coming from between two hangars. The third one was pretty. I hit my numbers all the way around the pattern and don't think I made a single adjustment to the cyclic on final. I ended up in a 3' hover right over the spot I was aiming for and went ahead and set it down. I called the tower and told 'em I wanted to hang out at the numbers and do some hover work. I was cleared and proceeded to work on pickups and set downs. I'm still not used to the tail down attitude these little dragonflies get when flying solo so the first few pickups were ugly to say the least. Set downs, on the other hand, are pretty much cake and I started making up games for myself to test my hovering skills. I'd hover taxi away from the numbers, turn around and pick one small spot to set down on and see how accurate I could be. Even in that last foot or so where I'd had so much trouble in the past was smooth. It got to the point where I was putting the wheel attachment point within just a few inches of where I wanted it and I was able to put the tip of the right skid right on the tip of the arrows leading to the displaced threshold several times. I tried some sideways hovering and managed to get it moving left pretty good, but right was a little erratic.. I had a hard time keeping the centerline right under my butt going that way.. Still, it was good practice. I noticed the CHT creeping up a bit so called the tower and asked to enter the pattern again. I was cleared after a few moments and off I went. Damn near busted the 800' pattern altitude 'cuz I was a bit slow in reducing power and got to my downwind checks. Everything was cool so I checked the clock to see how I was doing on time. 20 minutes before I had to head back to the ramp. I thought I'd get about 3 more patterns in after this one so got set up to make my base turn and flew a pretty good steep approach. Got a little too shallow right at the end, but that was fixed with a touch more collective.. Went around again and again, made a decent approach - not great, but not too bad.. The wind that caught me by surprise at 10' was still there, but I anticipated it and as soon as I felt the nose start to move, that left pedal got jammed in and the nose hardly budged.. Once into the hover I set it down and did some quick mental calcs. Ok, about 4 minutes per circuit, I've got a little over 10 minutes before I need to head back and it look like I've got about 7 or 8 gallons of fuel left in the main and a couple gallons in the aux. I'll do one more then call it a day. I call the tower to get cleared and I'm off again.. Crosswind and downwind legs are good, but I'm a bit too fast as I turn base and too high as I turn final. I get my angle set up good and have to lower the collective a bit more to get my descent rate up as I'm too high.. As I get it back on track, the rumble starts and I decide I'm going to make it a steep approach. I start to pull power and take a peek at the VSI.. Yikes.. 400fpm and I'm getting a bit slow. I figure I'm going to have to overshoot my spot even if I add power at this point I add some power and forward cyclic.. The rate of descent doesn't seem to be slowing and I really looks like I'm dropping rapidly and the airspeed is slowly creeping up.. At about 20' up the "oh ****s!" start and the ground is coming up pretty damned fast.. I add a handful of forward cyclic and drop the collective ever so slightly and as soon as the ship stops vibrating, I pull power and just get it stopped about 2' off the ground. I set down, collect my thoughts and pick it up. At least I've figured out how to pick up the ship solo without it wandering all over the place. I'm still uncomfortable with the "wheelie" liftoff.. I'd kinda like someone to take a video of me picking up solo so I can see how close to the ground the tail rotor is actually coming. I call tower and request a taxi back to the ramp and just as I turn around, I see Q standing near the fuel shack. Not sure if he'd just visited the soda machine or he was coming to see where I was. I was hoping he hadn't seen that last approach. If he did, there was no indication of it because as soon as I started down the runway towards the ramp, he turned and walked to the hangar. I taxied back and made a nice set down right in the center of the pad. throttled down, flicked the governor off and set the cool down timer and thought about that last few seconds of the last approach.. I'm not sure I actually got into settling with power and am thinking that I probably was just too slow adding power on final as the 1st part looked and felt pretty good. Either way, it was a really crappy way to get a helicopter back to Mother Earth and it definitely got my attention in a big way. Other than that approach, I thought I flew pretty good and looking back, I'm pleased I was able to execute a recovery for whatever the hell it was I'd got myself in to and not bend up a helicopter. Can't say the same for my ego though. Probably a damned good lesson in any case. Got the ship shut down and secured and can't help giving the ship a pat on the canopy and uttering "good girl". As I round the nose and start my walk back to the hangar, I see Q walking out towards me and I meet him halfway. "How'd it go?" "Did you see that last approach?" "I wasn't watching you.." "Good. I scared the crap out of myself." I went on to explain what happened and he kinda grinned and asked "Got into a little settling with power didja?" I had to admit that I probably had and told him what I'd done to get out of it. Q just smiled and walked away. Ok, I guess I did the right thing. I hit the "pilots lounge" and made two entries in my log book. 0.3 dual and 0.9 solo.. Q came up and asked how much time I logged and then told me he wanted be to blow through my next ten hours of solo so we could work on cross countries and asked me where I wanted to go. What a baited question.. I'd really like to fly over my mom's house and drop water balloons but I don't think the FAA would like that too much. I told Q I'd like to fly out over the desert and buzz the lizards and he said "Yeah, I'd like to do that too. Plan it out.." Cool. I'll give you one guess what I'm going to be doing later tonight.. Not sure we'll go any time soon with another storm coming through, but even if I end up flying dual in the pattern tomorrow, it'll be cool. Anytime I can get in the helicopter is great. I love this stuff! ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#4
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"The OTHER Kevin in San Diego" skiddz *AT* adelphia *DOT* net wrote in message We did some pilotage today and I can tell you this; it's a bitch to fly and mess with a sectional at the same time. I do a lot of 1000nm + cross countries in a chopper, and what I've found most useful is to prefold the sectionals in such a way that the route is readily unfolded. I used to even buy two copies of them so that wouldn't have to play the flip and refold game when I crossed the north-south boundary. I don't do that anymore because it gets expensive, but it was useful on my first few trips. IMO water features and railroad tracks are the most trustworthy things to use as reference points. Flying at a higher than normal altitude will help a lot to show you where you are on the sectional. I usually use about 2000 agl for medium cross-countries and 45-55 hundred for long ones. (My turbine works really good here + I get a free TAS increase from the altitude) The other reason to fly higher on cross countries is that you'll have less worry about towers & wires. Wires & towers are the biggest enemy of a helicopter pilot, especially when you're in unfamiliar territory. Your workload will be much lower if youre flying higher than anywhere a wire could be. BTW: In hilly terrain never fly lower than than the tops of the hills on each side, you'd be amazed how many wires there are acoss two mile wide valleys. You cant see the wires, so always look for structures and assume that theres a wire between them. Bart |
#5
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"B4RT" wrote in message
... I usually use about 2000 agl for medium cross-countries and 45-55 hundred for long ones. (My turbine works really good here + I get a free TAS increase from the altitude) The other reason to fly higher on cross countries is that you'll have less worry about towers & wires. Bart Ok, I'm a bit confused here. So Bart, or Kevin, or anyone who cares to put in their 2 cents worth, have at it. :-) My issue is with Bart's statement that there's a free TAS increase in his helicopter with altitude. I'm sitting here, thinking about how I want to word all of this and I'm starting to think that I'm about to answer my own question so I'll put it to you kind folks and see what comes back! I understand that fixed wing aircraft gain efficiency with altitude. The simplified explanation is that as the aircraft climbs to greater altitudes (ie: thinner air), there's less frictional drag on the airframe and the aircraft achieves a higher TAS (true airspeed for those who may not know) as long as you're not flying so high that you're no longer able to pull standard cruise power from the engine. Assuming the same power settings from the engine/engines, you'll achieve a higher cruising airspeed (TAS) at altitude than you will at sea level. All of this happens automatically. As for helicopters (any rotorcraft), the airspeed of the "wings" (ie: the rotor blades) is limited to the maximum rpm that the rotor system can sustain. Because of this, as the helicopter climbs to altitude, the rotor blades can't see the kind of TAS increase that a fixed wing aircraft enjoys because the speed of the rotor blades is tied to the max rpm of the rotor system. Consequently, as the air thins with increased altitude, the helicopter has to fly with ever increasing collective settings to maintain the same lift/thrust levels. When you can't increase airspeed (rotor rpm), you have to increase AOA (collective) to maintain a given lift/thrust level!? One negative side effect of this is that the helicopters Vne speeds lower as the altitude rises. What I've always been told is that because of this, it doesn't generally pay for a helicopter to go to altitude on a x-country flights unless there are sufficient favorable winds (ie: tail winds!) to make up the difference. (?) Now to the part where I might be answering my own question. Just as the fixed wing aircraft sees in increase in TAS at altitude as long as it can still maintain cruise power (generally 65 to 75% power), I'm starting to think (I hadn't really considered it this way before!) that as long as the helicopter isn't pushing it's Vne limits at altitude (due to higher collective settings), the fuselage will see an increase in TAS also, even if the rotor blades themselves are not, because of rpm limitations on the main rotor system. Of course, if the fuse is seeing a higher TAS, then the rotor blades will also see in increase, at least on the advancing side..........but I don't think I want to get into that too deeply! ;-) Am I getting this anywhere near right? I hope this makes sense. Thanks for any replies! :-) Fly Safe, Steve R. |
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Remember, TAS is your airspeed (ignoring the winds) in relation to the
ground. IAS is to the air around you. The higher you go, the less drag on the fuselage and same as a fixed wing, less drag on lift prducing surfaces mean more efficiency, which means a little better airspeed. That IAS maybe lower due to less power, but for that amount of power you are more efficient. That all adds up to higher TAS and lower fuel burns. In the turbine I fly, I see up to a 5-6 gallon an hour less burn at 5,000'. On Fri, 29 Oct 2004 13:56:01 GMT, "Steve R." wrote: "B4RT" wrote in message ... I usually use about 2000 agl for medium cross-countries and 45-55 hundred for long ones. (My turbine works really good here + I get a free TAS increase from the altitude) The other reason to fly higher on cross countries is that you'll have less worry about towers & wires. Bart Ok, I'm a bit confused here. So Bart, or Kevin, or anyone who cares to put in their 2 cents worth, have at it. :-) My issue is with Bart's statement that there's a free TAS increase in his helicopter with altitude. I'm sitting here, thinking about how I want to word all of this and I'm starting to think that I'm about to answer my own question so I'll put it to you kind folks and see what comes back! I understand that fixed wing aircraft gain efficiency with altitude. The simplified explanation is that as the aircraft climbs to greater altitudes (ie: thinner air), there's less frictional drag on the airframe and the aircraft achieves a higher TAS (true airspeed for those who may not know) as long as you're not flying so high that you're no longer able to pull standard cruise power from the engine. Assuming the same power settings from the engine/engines, you'll achieve a higher cruising airspeed (TAS) at altitude than you will at sea level. All of this happens automatically. As for helicopters (any rotorcraft), the airspeed of the "wings" (ie: the rotor blades) is limited to the maximum rpm that the rotor system can sustain. Because of this, as the helicopter climbs to altitude, the rotor blades can't see the kind of TAS increase that a fixed wing aircraft enjoys because the speed of the rotor blades is tied to the max rpm of the rotor system. Consequently, as the air thins with increased altitude, the helicopter has to fly with ever increasing collective settings to maintain the same lift/thrust levels. When you can't increase airspeed (rotor rpm), you have to increase AOA (collective) to maintain a given lift/thrust level!? One negative side effect of this is that the helicopters Vne speeds lower as the altitude rises. What I've always been told is that because of this, it doesn't generally pay for a helicopter to go to altitude on a x-country flights unless there are sufficient favorable winds (ie: tail winds!) to make up the difference. (?) Now to the part where I might be answering my own question. Just as the fixed wing aircraft sees in increase in TAS at altitude as long as it can still maintain cruise power (generally 65 to 75% power), I'm starting to think (I hadn't really considered it this way before!) that as long as the helicopter isn't pushing it's Vne limits at altitude (due to higher collective settings), the fuselage will see an increase in TAS also, even if the rotor blades themselves are not, because of rpm limitations on the main rotor system. Of course, if the fuse is seeing a higher TAS, then the rotor blades will also see in increase, at least on the advancing side..........but I don't think I want to get into that too deeply! ;-) Am I getting this anywhere near right? I hope this makes sense. Thanks for any replies! :-) Fly Safe, Steve R. |
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Hi!
I had a long drawn out reply to your first sentence (about TAS, CAS, and IAS) until I re-read it and paid more attention to the "ignoring the winds" part! ;-) I agree, assuming absolutely NO wind, TAS should equal ground speed if we're doing the calculations correctly. Since that's never the case (the part about absolutely NO wind that is), for all intents and purposes, I try to never equate airspeed and ground speed as the same thing although the first will obviously have an impact on the second. The only reason I mentioned tail winds in my original question was to clarify that if you've got a good enough tail wind, your ground speed will be up enough to compensate for any airspeed losses that occur due to the increased altitude. I hear what you're saying about less drag on the lift producing surfaces (wings!) but aren't you also having to fly at greater collective settings in the "relatively" thin air? From what I think I'm getting out of all this, that minor change isn't hurting you enough to offset the gains of climbing up to 5000 feet and the improved fuel burn (5-6 gallons/hr isn't chump change these days!) doesn't hurt a bit either. In the turbine helicopter you fly, where is the point of diminishing returns? In other words, how high can you go before any improvement in TAS or fuel consumption quits netting you any gain? Thanks for the reply. Fly Safe, Steve R. hellothere.adelphia.net wrote in message ... Remember, TAS is your airspeed (ignoring the winds) in relation to the ground. IAS is to the air around you. The higher you go, the less drag on the fuselage and same as a fixed wing, less drag on lift prducing surfaces mean more efficiency, which means a little better airspeed. That IAS maybe lower due to less power, but for that amount of power you are more efficient. That all adds up to higher TAS and lower fuel burns. In the turbine I fly, I see up to a 5-6 gallon an hour less burn at 5,000'. On Fri, 29 Oct 2004 13:56:01 GMT, "Steve R." wrote: "B4RT" wrote in message ... I usually use about 2000 agl for medium cross-countries and 45-55 hundred for long ones. (My turbine works really good here + I get a free TAS increase from the altitude) The other reason to fly higher on cross countries is that you'll have less worry about towers & wires. Bart Ok, I'm a bit confused here. So Bart, or Kevin, or anyone who cares to put in their 2 cents worth, have at it. :-) My issue is with Bart's statement that there's a free TAS increase in his helicopter with altitude. I'm sitting here, thinking about how I want to word all of this and I'm starting to think that I'm about to answer my own question so I'll put it to you kind folks and see what comes back! I understand that fixed wing aircraft gain efficiency with altitude. The simplified explanation is that as the aircraft climbs to greater altitudes (ie: thinner air), there's less frictional drag on the airframe and the aircraft achieves a higher TAS (true airspeed for those who may not know) as long as you're not flying so high that you're no longer able to pull standard cruise power from the engine. Assuming the same power settings from the engine/engines, you'll achieve a higher cruising airspeed (TAS) at altitude than you will at sea level. All of this happens automatically. As for helicopters (any rotorcraft), the airspeed of the "wings" (ie: the rotor blades) is limited to the maximum rpm that the rotor system can sustain. Because of this, as the helicopter climbs to altitude, the rotor blades can't see the kind of TAS increase that a fixed wing aircraft enjoys because the speed of the rotor blades is tied to the max rpm of the rotor system. Consequently, as the air thins with increased altitude, the helicopter has to fly with ever increasing collective settings to maintain the same lift/thrust levels. When you can't increase airspeed (rotor rpm), you have to increase AOA (collective) to maintain a given lift/thrust level!? One negative side effect of this is that the helicopters Vne speeds lower as the altitude rises. What I've always been told is that because of this, it doesn't generally pay for a helicopter to go to altitude on a x-country flights unless there are sufficient favorable winds (ie: tail winds!) to make up the difference. (?) Now to the part where I might be answering my own question. Just as the fixed wing aircraft sees in increase in TAS at altitude as long as it can still maintain cruise power (generally 65 to 75% power), I'm starting to think (I hadn't really considered it this way before!) that as long as the helicopter isn't pushing it's Vne limits at altitude (due to higher collective settings), the fuselage will see an increase in TAS also, even if the rotor blades themselves are not, because of rpm limitations on the main rotor system. Of course, if the fuse is seeing a higher TAS, then the rotor blades will also see in increase, at least on the advancing side..........but I don't think I want to get into that too deeply! ;-) Am I getting this anywhere near right? I hope this makes sense. Thanks for any replies! :-) Fly Safe, Steve R. |
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"Steve R." wrote in
: Hi! Am I getting this anywhere near right? I hope this makes sense. Thanks for any replies! :-) Fly Safe, Steve R. Sorry to wade into this discussion without a bit more prep but having read your reply to the post something occurred to me that might help. The way turbine engines work mean that as the air gets colder (perhaps due to low surface temp or climbing to higher alt for example) they become more efficient and generate more power for a given power setting. The 'laymans' (i.e. my!) logic for this is that since turbines work by heating air, the cooler the air at the intake, the more the air can be heated by the engine thus producing greater thrust. I suspect that the reason for the lower fuel burn is due to this effect, rather than the lower drag. toad. |
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Toad-Man wrote:
The way turbine engines work mean that as the air gets colder (perhaps due to low surface temp or climbing to higher alt for example) they become more efficient and generate more power for a given power setting. The 'laymans' (i.e. my!) logic for this is that since turbines work by heating air, the cooler the air at the intake, the more the air can be heated by the engine thus producing greater thrust. This is part of it, the other part is the flame temperature in the engine is much hotter, because the air is less dense while you use approximately the same amount of fuel to generate as much power (or thrust in a jet engine). So you not only have cooler intake air, you also have much hotter turbine inlet air. |
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Steve,
Indicated airspeed is just a measure of how many little molecules are banging against the pressure transducer. The higher you go, the fewer of these little guys there are per unit volume of air. Since the chopper has to bang the same number of molecules to produce lift and thrust up high as it does down low, the only thing that really changes is volume of air that is being traversed (read TAS increase). If you think about it, you'll find that most of the things that hold true in airplanes also hold true in helicopters with regard to the lift and thrust vector math that go into the TAS. Even if I didnt know the junk that went into this, I can see the effect directly by watching my GS increase on my EFIS/GPS. The chopper maintains about 110kts indicated, but the TAS is around 120. Meanwhile my burn goes from about 26.5GPH down to about 24.5. Of course the increased winds aloft can kick the snot out of this benefit if theyre not beneficial. But one day I got the biggest kick out of doing 165-170 knots on my way down the florida keys. Approach actually called me and asked what kind of helicopter I was in. Bart "Steve R." wrote in message ... Ok, I'm a bit confused here. So Bart, or Kevin, or anyone who cares to put in their 2 cents worth, have at it. :-) My issue is with Bart's statement that there's a free TAS increase in his helicopter with altitude. |
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