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

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

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.

Have you been able to establish a projected date when your first prototype
will fly?

On the sage advice of Greg Cole, the developer of the delightful
little SparrowHawk, I tell everybody that it will fly on Tuesday.
Week, month, and year TBD, but the day will be Tuesday.

When the weather warms up, we'll start molding a pair or two of wings,
and that might hold promise for flight this year, but I'm not holding
breath. However, I do remain confident that there is a growing market
for what I'm doing, so long as I do it right.

If anybody wants one pretty bad, and wants to hurry the project up a
bit, I'm open to the idea of taking on some help. I can guarantee
you'd learn some pretty crafty ways of doing high-tech composites with
low-tech tools. But be warned I'm pretty picky about who I let into
the shop.

Thanks, Bob K.

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

"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.

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

"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

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...

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