Yes it is! There is absolutely no other mode of flying that allows one to launch into the thin air from a flat field, off of your own two feet. It's simply amazing the feeling! Free-flight off a mountain is fun too, quieter. But FLPHG is awesome if you have the ability to maintain your engine/harness well. Many people try to get into FLPHG but find that it's too much hassle to commit to the dirty work of maintenance. That fact can be good for others who don't mind the extra challenges of keeping an engine running well and purchase these harnesses reasonably inexpensively on the used markets.
Ben, you didn't indicate what your typical WOT static rpm is with the expansion chamber exhaust system, nor the pitch and diameter of the prop. Density altitude also has an effect. My engine has the Red-Head modification to it's cylinder (cylinder top is cut off, and a higher-compression head is mated to the cylinder as in a typical air-cooled MX bike and/or kart engine (KT100 / KA100). I have also done quite a bit of porting work and substantially reduced the mass of the piston. As mentioned before, I have the WB-39 carb in place that offers far better mixture adjustment and more air-flow due to it's larger venturi. My typical WOT static rpm is 9700-9850 rpm, depending on A/F tune. If I tune it to the ragged edge (max CHT, max EGT), I can attain 9850 rpm static. My typical 'safer' A/F tune is right around 9700-9750 rpm where it's RoP (rich of peak). The prop is a carbon Bolly one-piece of 22.5"x54". The measured chord angles and resultant calculated pitches actually vary a bit from the root to the tips; 21" pitch at the root, 22.5" at 75% of the radius, and 22" at the tips. The fastening of the prop hub on the prop-shaft does have about 10-12 degrees of backlash due to the imperfect fit of the retaining bolt. It's likely losing at least 100 rpm because of that backlash. Same thing happens if there is any torsional flex in the prop-shaft. One thing is very apparent though, and that is about 15 seconds after the engine attains max WOT rpms, it begins to lose rpms at a rate of about 10 rpms per second. The WOT rpms come right back up to max after releasing the throttle to around 75% for a few seconds, then WOT again. I have had a few theories about the cause of this, but none have solved the situation completely. My latest theory is that the exhaust gasses within the expansion chamber and the chamber's steel shell become too hot (for the chamber's length) so that the pressure waves travel too fast within the chamber and end up cramming too much spent exhaust gas into the combustion chamber before the piston closes the exhaust port. The proposed solution for this is a little involved and I won't delve into this right now. A little feed-back from Ben would be cool.🙂
I believe that my highly-modified Raket is producing about 17.5 hp, maybe more. In measuring static thrust with a digital scale, it's producing about +125 lbF (57 kgF; 556 N). I weigh 215 lbs, 225 lbs dressed for 65 deg F. flying weather. It typically launches me within 11-12 running steps, so the launching-run is about 33-40 ft. I can climb at roughly 500 fpm while in a turn, about +600 fpm in a straight climb, depending on the DA.
@@SagaSeaCraft All it would take is some turbulence to get him out of shape and the G forces would whip that propeller up into the wing fabric. What's to stop it ?
@@thomassawicki2065 Pretty much all of us fly flphg without any major life-threatening mishaps other than possibly having less-than-photogenic landings, or at worse smacking the propeller on uneven ground or getting tangled-up in soybean crops. The prop is far enough behind from the wing's sail that it won't cut the sail unless somehow the pilot allows the harness to wildly yaw too far. Even if that happens while flying, there won't be a big problem as long as the pilot gets the harness back on centerline and lands the craft soon afterwards. I would say that 100% of flphg pilots in the USA have had quite a lot of HG free-flight experience before ever attempting flphg flight. There are a very few in Sweden that have learned flphg without freeflight experience. But the point being that in order to be reasonably safe flying a FLPHG, a pilot should first have much experience and skill in free-flight. Just as with any other form of flying, a flphg pilot must know the atmospheric conditions and determine that the conditions are appropriate for his craft. If conditions are too active or are forecasted to degrade within the flight's time-span, then you don't fly. All forms of flight have risks. It's the pilot's job to minimize the risks through good judgement, skill, and proper maintenance. So, just as I indicated previously, you might want to do more research into flphg before making such broad, unsubstantiated statements.You might even want to try flphg if you are already a HG pilot.🙂
@@thomassawicki2065 Well, first of all, any pilot of any aircraft should be aware of the atmospheric conditions before launching. If it's too active for your aircraft type and/or your skill level, then you don't fly. However, I've flown in very active soaring conditions with my flphg without any real handling problems. It's just that the pilot must judge for himself the conditions that he can skillfully fly in. Also, my flphg harness has a 'drag strut' that prevents the glider and prop from interfering with one another. Even during non-photogenic landings it has saved my prop. Other pilots fly with limiting-lines that prevent side-to-side swing of the harness' aft end, which of course prevents prop-sail interference. However, I've never had an instance where my prop ever came close to taking a bite out of my sail. It really comes down to pilot judgement and skill, just as in any other aircraft, large or small. FLPHG is really very much fun. You should look into it and try it out for yourself.
Well, first of all, any pilot of any aircraft should be aware of the atmospheric conditions before launching. If it's too active for your aircraft type and/or your skill level, then you don't fly. However, I've flown in very active soaring conditions with my flphg without any real handling problems. It's just that the pilot must judge for himself the conditions that he can skillfully fly in. Also, my flphg harness has a 'drag strut' that prevents the glider and prop from interfering with one another. Even during non-photogenic landings it has saved my prop. Other pilots fly with limiting-lines that prevent side-to-side swing of the harness' aft end, which of course prevents prop-sail interference. However, I've never had an instance where my prop ever came close to taking a bite out of my sail. It really comes down to pilot judgement and skill, just as in any other aircraft, large or small. FLPHG is really very much fun. You should look into it and try it out for yourself.
Coolest way to fly.
Yes it is! There is absolutely no other mode of flying that allows one to launch into the thin air from a flat field, off of your own two feet. It's simply amazing the feeling! Free-flight off a mountain is fun too, quieter. But FLPHG is awesome if you have the ability to maintain your engine/harness well. Many people try to get into FLPHG but find that it's too much hassle to commit to the dirty work of maintenance. That fact can be good for others who don't mind the extra challenges of keeping an engine running well and purchase these harnesses reasonably inexpensively on the used markets.
Ben, you didn't indicate what your typical WOT static rpm is with the expansion chamber exhaust system, nor the pitch and diameter of the prop. Density altitude also has an effect.
My engine has the Red-Head modification to it's cylinder (cylinder top is cut off, and a higher-compression head is mated to the cylinder as in a typical air-cooled MX bike and/or kart engine (KT100 / KA100). I have also done quite a bit of porting work and substantially reduced the mass of the piston. As mentioned before, I have the WB-39 carb in place that offers far better mixture adjustment and more air-flow due to it's larger venturi.
My typical WOT static rpm is 9700-9850 rpm, depending on A/F tune. If I tune it to the ragged edge (max CHT, max EGT), I can attain 9850 rpm static. My typical 'safer' A/F tune is right around 9700-9750 rpm where it's RoP (rich of peak).
The prop is a carbon Bolly one-piece of 22.5"x54". The measured chord angles and resultant calculated pitches actually vary a bit from the root to the tips; 21" pitch at the root, 22.5" at 75% of the radius, and 22" at the tips. The fastening of the prop hub on the prop-shaft does have about 10-12 degrees of backlash due to the imperfect fit of the retaining bolt. It's likely losing at least 100 rpm because of that backlash. Same thing happens if there is any torsional flex in the prop-shaft.
One thing is very apparent though, and that is about 15 seconds after the engine attains max WOT rpms, it begins to lose rpms at a rate of about 10 rpms per second. The WOT rpms come right back up to max after releasing the throttle to around 75% for a few seconds, then WOT again. I have had a few theories about the cause of this, but none have solved the situation completely. My latest theory is that the exhaust gasses within the expansion chamber and the chamber's steel shell become too hot (for the chamber's length) so that the pressure waves travel too fast within the chamber and end up cramming too much spent exhaust gas into the combustion chamber before the piston closes the exhaust port. The proposed solution for this is a little involved and I won't delve into this right now.
A little feed-back from Ben would be cool.🙂
Fantastic, how many hp and or how much thrust are you getting? Thanks!
I believe that my highly-modified Raket is producing about 17.5 hp, maybe more. In measuring static thrust with a digital scale, it's producing about +125 lbF (57 kgF; 556 N). I weigh 215 lbs, 225 lbs dressed for 65 deg F. flying weather. It typically launches me within 11-12 running steps, so the launching-run is about 33-40 ft. I can climb at roughly 500 fpm while in a turn, about +600 fpm in a straight climb, depending on the DA.
That contraption looks to have many ways to fail .
The propeller could get you, or the wing, or all those wires.
Do some homework before making silly comments. You might learn something.
@@SagaSeaCraft
All it would take is some turbulence to get him out of shape and the G forces would whip that propeller up into the wing fabric.
What's to stop it ?
@@thomassawicki2065 Pretty much all of us fly flphg without any major life-threatening mishaps other than possibly having less-than-photogenic landings, or at worse smacking the propeller on uneven ground or getting tangled-up in soybean crops. The prop is far enough behind from the wing's sail that it won't cut the sail unless somehow the pilot allows the harness to wildly yaw too far. Even if that happens while flying, there won't be a big problem as long as the pilot gets the harness back on centerline and lands the craft soon afterwards.
I would say that 100% of flphg pilots in the USA have had quite a lot of HG free-flight experience before ever attempting flphg flight. There are a very few in Sweden that have learned flphg without freeflight experience. But the point being that in order to be reasonably safe flying a FLPHG, a pilot should first have much experience and skill in free-flight.
Just as with any other form of flying, a flphg pilot must know the atmospheric conditions and determine that the conditions are appropriate for his craft. If conditions are too active or are forecasted to degrade within the flight's time-span, then you don't fly.
All forms of flight have risks. It's the pilot's job to minimize the risks through good judgement, skill, and proper maintenance.
So, just as I indicated previously, you might want to do more research into flphg before making such broad, unsubstantiated statements.You might even want to try flphg if you are already a HG pilot.🙂
@@thomassawicki2065 Well, first of all, any pilot of any aircraft should be aware of the atmospheric conditions before launching. If it's too active for your aircraft type and/or your skill level, then you don't fly.
However, I've flown in very active soaring conditions with my flphg without any real handling problems. It's just that the pilot must judge for himself the conditions that he can skillfully fly in.
Also, my flphg harness has a 'drag strut' that prevents the glider and prop from interfering with one another. Even during non-photogenic landings it has saved my prop. Other pilots fly with limiting-lines that prevent side-to-side swing of the harness' aft end, which of course prevents prop-sail interference. However, I've never had an instance where my prop ever came close to taking a bite out of my sail. It really comes down to pilot judgement and skill, just as in any other aircraft, large or small.
FLPHG is really very much fun. You should look into it and try it out for yourself.
Well, first of all, any pilot of any aircraft should be aware of the atmospheric conditions before launching. If it's too active for your aircraft type and/or your skill level, then you don't fly.
However, I've flown in very active soaring conditions with my flphg without any real handling problems. It's just that the pilot must judge for himself the conditions that he can skillfully fly in.
Also, my flphg harness has a 'drag strut' that prevents the glider and prop from interfering with one another. Even during non-photogenic landings it has saved my prop. Other pilots fly with limiting-lines that prevent side-to-side swing of the harness' aft end, which of course prevents prop-sail interference. However, I've never had an instance where my prop ever came close to taking a bite out of my sail. It really comes down to pilot judgement and skill, just as in any other aircraft, large or small.
FLPHG is really very much fun. You should look into it and try it out for yourself.