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#1
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HP-24 Project
Bob,
I have been following the development of your HP-24 for the past seven years. I continue to be amazed at the amount of work that is involved in producing a composite aircraft kit. In addition, I have been amazed at your build skills and creativity. (http://www.hpaircraft.com/hp-24/) Have you been able to establish a projected date when your first prototype will fly? Wayne HP-14 "6F" http://www.soaridaho.com/Schreder |
#2
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HP-24 Project
Wayne Paul wrote:
Bob, I have been following the development of your HP-24 for the past seven years. I continue to be amazed at the amount of work that is involved in producing a composite aircraft kit. In addition, I have been amazed at your build skills and creativity. (http://www.hpaircraft.com/hp-24/) Forgive my ignorance but what is the 200 pounds of water ballast for? Tony |
#3
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HP-24 Project
On Feb 13, 11:57*am, Anthony W wrote:
Forgive my ignorance but what is the 200 pounds of water ballast for? Carrying water ballast is common in soaring contests, and also for long flights where speed is essential to achieving distance. The increased weight increases both forward speed and sinking speed in proportion, so that the maximum glide ratio does not change. The only change is that increased weight increases the speed at which the best glide is encountered. My understanding is that this basically holds true right up to where the speeds are great enough that you encounter transonic effects and the rules start changing. I can't remember what sort of wing loading that is, but I ran the rho-v-squared numbers back when Linda Wolkovich called me about the Concrete Glider episode, and the numbers were surprisingly large. It's theoretically possible to cast a ferro- concrete version of a modern sailplane weighing several tons and have it glide at the same ratio as its lighter composite bretheren. The only problem would be launching it - the man-carrying, roll-off- hilltop glider that Linda originally wanted wasn't going to happen. At soaring contests, pilots evaluate the weather and ballast accordingly. When the lift is predicted to be strong, they carry lots. When its weak, they don't. Over the course of the soaring day, pilots re-evaluate their situation and dump ballast as they see necessary. They always (they should, at least) dump all ballast before landing to reduce landing energy to the bare minimum. Anyhow, when you see speeds up around (and sometimes over) 100 mph for 300 or 400 mile tasks at Nevada contests, you know those guys are ballasted to up around 9.5 lbs/ft^2. That takes way more water than 200 lbs, but I figured I'd start there and then maybe test uphill from there (or let others do it). Thanks, Bob K. |
#4
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HP-24 Project
Bob Kuykendall wrote:
On Feb 13, 11:57 am, Anthony W wrote: Forgive my ignorance but what is the 200 pounds of water ballast for? Carrying water ballast is common in soaring contests, and also for long flights where speed is essential to achieving distance. The increased weight increases both forward speed and sinking speed in proportion, so that the maximum glide ratio does not change. The only change is that increased weight increases the speed at which the best glide is encountered. My understanding is that this basically holds true right up to where the speeds are great enough that you encounter transonic effects and the rules start changing. I can't remember what sort of wing loading that is, but I ran the rho-v-squared numbers back when Linda Wolkovich called me about the Concrete Glider episode, and the numbers were surprisingly large. It's theoretically possible to cast a ferro- concrete version of a modern sailplane weighing several tons and have it glide at the same ratio as its lighter composite bretheren. The only problem would be launching it - the man-carrying, roll-off- hilltop glider that Linda originally wanted wasn't going to happen. At soaring contests, pilots evaluate the weather and ballast accordingly. When the lift is predicted to be strong, they carry lots. When its weak, they don't. Over the course of the soaring day, pilots re-evaluate their situation and dump ballast as they see necessary. They always (they should, at least) dump all ballast before landing to reduce landing energy to the bare minimum. Anyhow, when you see speeds up around (and sometimes over) 100 mph for 300 or 400 mile tasks at Nevada contests, you know those guys are ballasted to up around 9.5 lbs/ft^2. That takes way more water than 200 lbs, but I figured I'd start there and then maybe test uphill from there (or let others do it). Thanks, Bob K. So let me get this straight. Unlike in powered flight, pilot weight isn't a problem? So guys like Chuck S. and myself could fly one of these? Tony |
#5
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HP-24 Project
"Anthony W" wrote in message
news:fwJsj.332$ph.312@trnddc06... Bob Kuykendall wrote: On Feb 13, 11:57 am, Anthony W wrote: ... So let me get this straight. Unlike in powered flight, pilot weight isn't a problem? So guys like Chuck S. and myself could fly one of these? Tony If only it were that simple... Water ballast is typically carried in the wings so to not stress the airframe and wing root connections (remember, the wings are removable with minimal to no tools - just to complicate the situation). The maximum design load for the cockpit is usually not that high - I see a target weight for the HP-24 of 300 pounds. And, unlike water ballast, you can't perform do-it-youself lyposuction to shed weight if the day gets a little weak and you are having trouble making it back home. The glide angle is the same, but at higher weights, the higher sink rate means you need stronger lift to regain altitude. Ain't no such thing as a free lunch, eh? Plus, if you are serious about performance, then you end up with a cockpit that is often a bit tight for plus size individuals - dunno how roomy the HP-24 is. -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#6
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HP-24 Project
Capt. Geoffrey Thorpe wrote:
"Anthony W" wrote in message news:fwJsj.332$ph.312@trnddc06... Bob Kuykendall wrote: On Feb 13, 11:57 am, Anthony W wrote: ... So let me get this straight. Unlike in powered flight, pilot weight isn't a problem? So guys like Chuck S. and myself could fly one of these? Tony If only it were that simple... Water ballast is typically carried in the wings so to not stress the airframe and wing root connections (remember, the wings are removable with minimal to no tools - just to complicate the situation). The maximum design load for the cockpit is usually not that high - I see a target weight for the HP-24 of 300 pounds. And, unlike water ballast, you can't perform do-it-youself lyposuction to shed weight if the day gets a little weak and you are having trouble making it back home. The glide angle is the same, but at higher weights, the higher sink rate means you need stronger lift to regain altitude. Ain't no such thing as a free lunch, eh? Plus, if you are serious about performance, then you end up with a cockpit that is often a bit tight for plus size individuals - dunno how roomy the HP-24 is. My problem with flying (besides money) is that I was 6'7" before my back injury and weight builds fast on tall guys. At my perfect weight I'm too heavy for 90% of the planes I'd like to fly (and I'm far from my perfect weight.) I'm mostly looking at small 2 seaters to build in a single seat configuration. I'm looking to build something under the LSA rules so I don't have to pass the physical to fly it. Tony |
#7
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HP-24 Project
Anthony W wrote:
Bob Kuykendall wrote: On Feb 13, 11:57 am, Anthony W wrote: Forgive my ignorance but what is the 200 pounds of water ballast for? Carrying water ballast is common in soaring contests, and also for long flights where speed is essential to achieving distance. The increased weight increases both forward speed and sinking speed in proportion, so that the maximum glide ratio does not change. The only change is that increased weight increases the speed at which the best glide is encountered. My understanding is that this basically holds true right up to where the speeds are great enough that you encounter transonic effects and the rules start changing. I can't remember what sort of wing loading that is, but I ran the rho-v-squared numbers back when Linda Wolkovich called me about the Concrete Glider episode, and the numbers were surprisingly large. It's theoretically possible to cast a ferro- concrete version of a modern sailplane weighing several tons and have it glide at the same ratio as its lighter composite bretheren. The only problem would be launching it - the man-carrying, roll-off- hilltop glider that Linda originally wanted wasn't going to happen. At soaring contests, pilots evaluate the weather and ballast accordingly. When the lift is predicted to be strong, they carry lots. When its weak, they don't. Over the course of the soaring day, pilots re-evaluate their situation and dump ballast as they see necessary. They always (they should, at least) dump all ballast before landing to reduce landing energy to the bare minimum. Anyhow, when you see speeds up around (and sometimes over) 100 mph for 300 or 400 mile tasks at Nevada contests, you know those guys are ballasted to up around 9.5 lbs/ft^2. That takes way more water than 200 lbs, but I figured I'd start there and then maybe test uphill from there (or let others do it). Thanks, Bob K. So let me get this straight. Unlike in powered flight, pilot weight isn't a problem? So guys like Chuck S. and myself could fly one of these? Tony As long as you are prepared to "shed some ballast" when necessary... |
#8
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HP-24 Project
On Feb 13, 6:06*pm, cavalamb himself wrote:
Anthony W wrote: Bob Kuykendall wrote: On Feb 13, 11:57 am, Anthony W wrote: Forgive my ignorance but what is the 200 pounds of water ballast for? Carrying water ballast is common in soaring contests, and also for long flights where speed is essential to achieving distance. The increased weight increases both forward speed and sinking speed in proportion, so that the maximum glide ratio does not change. The only change is that increased weight increases the speed at which the best glide is encountered. My understanding is that this basically holds true right up to where the speeds are great enough that you encounter transonic effects and the rules start changing. I can't remember what sort of wing loading that is, but I ran the rho-v-squared numbers back when Linda Wolkovich called me about the Concrete Glider episode, and the numbers were surprisingly large. It's theoretically possible to cast a ferro- concrete version of a modern sailplane weighing several tons and have it glide at the same ratio as its lighter composite bretheren. The only problem would be launching it - the man-carrying, roll-off- hilltop glider that Linda originally wanted wasn't going to happen. At soaring contests, pilots evaluate the weather and ballast accordingly. When the lift is predicted to be strong, they carry lots. When its weak, they don't. Over the course of the soaring day, pilots re-evaluate their situation and dump ballast as they see necessary. They always (they should, at least) dump all ballast before landing to reduce landing energy to the bare minimum. Anyhow, when you see speeds up around (and sometimes over) 100 mph for 300 or 400 mile tasks at Nevada contests, you know those guys are ballasted to up around 9.5 lbs/ft^2. That takes way more water than 200 lbs, but I figured I'd start there and then maybe test uphill from there (or let others do it). Thanks, Bob K. So let me get this straight. *Unlike in powered flight, pilot weight isn't a problem? *So guys like Chuck S. and myself could fly one of these? Tony As long as you are prepared to "shed some ballast" when necessary...- Hide quoted text - - Show quoted text - Damn, that leaves Chuck S in a real fix now doesn't it. BFG |
#9
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HP-24 Project
cavalamb himself wrote:
As long as you are prepared to "shed some ballast" when necessary... Is that like taking a dump in flight? ;o) Tony |
#10
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HP-24 Project
"Anthony W" wrote in message news:fwJsj.332$ph.312@trnddc06... Anyhow, when you see speeds up around (and sometimes over) 100 mph for 300 or 400 mile tasks at Nevada contests, you know those guys are ballasted to up around 9.5 lbs/ft^2. That takes way more water than 200 lbs, but I figured I'd start there and then maybe test uphill from there (or let others do it). Thanks, Bob K. So let me get this straight. Unlike in powered flight, pilot weight isn't a problem? So guys like Chuck S. and myself could fly one of these? Tony, You don't get something for nothing in a sailplane. The situation of weight affects your power plane in the same way it does a glider. If you look at the max range speeds of your airplane you will see the max range speed increases as wing loading increases. Of course you will also note that it takes a higher power setting to maintain level flights at the higher gross weight speeds. Lift conditions for a sailplane is their power. When meteorological conditions are predicted to be strong, (lots of power) we fly at high wingloading. If the conditions weaken, the water ballast is dumped thus lowering the wingloading. Ballast is carried in the wings, not the fuselage. The wing tanks have little effect on weight and balance. A pilots weight affect weight and balance. For a heavy pilot, weight must be added to the tail. Additionally, many gliders have maximum fuselage weight limits. The biggest problem a heavy pilot has is fitting into the cockpit. http://www.soaridaho.com/Schreder/HP-18/N15DP/N15DP.htm http://www.soaridaho.com/photogaller...ey/Roger_1.jpg http://www.soaridaho.com/Schreder/HP...Test_Brian.jpg I hope this has been helpful, Wayne HP-14 "6F" http://www.soaridaho.com/Flights/6F_Gold_Distance.html |
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