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Diana-2 - master-piece or flop?



 
 
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  #1  
Old June 16th 07, 06:55 AM posted to rec.aviation.soaring
BlueCumulus[_2_]
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Posts: 37
Default Diana-2 - master-piece or flop?

I have read very good critics about Diana-2
but as well very bad news about it.

The good news are from the people who seem to have flown the first two
Prototypes. The bad rumors I heard about number-3 of Diana-2.
Obviously the main difference is, that the wing position was shifted some
centimeters to the front. The glider appeared in Australia last November,
flew with experimental permit, but never got the airworthiness approval from
the Australian Airworthiness Authorities.

The gossip mentions problems like:
- airbrake movements being asynchronous
- flap handle unlocking in flight and shifting to full positive
- too high flap handling forces (more than JAR22 limits)
- weak aileron control at take off until tail wheel is off the ground
- glider is stalling while thermaling over inner wing at speeds CLmax with
- aileron control not good enough to keep bank when circling 30deg
- glider was in general instable to fly in yaw and pitch

Did anyone fly serial planes of Diana-2 with manufacturing numbers 3?


  #2  
Old June 16th 07, 01:24 PM posted to rec.aviation.soaring
[email protected]
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Posts: 154
Default Diana-2 - master-piece or flop?

- flap handle unlocking in flight and shifting to full positive

I'm curious. How can flaps self-deploy to full positive given in-
flight airflow? Are they somehow balanced?


- too high flap handling forces (more than JAR22 limits)

This one seems to contradict the first one. If it takes a lot of force
to deploy the flaps, how can they self-deploy to full positive?



  #3  
Old June 16th 07, 09:44 PM posted to rec.aviation.soaring
BlueCumulus[_2_]
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Posts: 37
Default Diana-2 - master-piece or flop?

it is not contradictory

- it needs much force to push the flaps to negative position
- when you fly fast through a thermal or turbulence the handle unhooked
and comes fully back into positive position, unless you hold it
permanently
in your hand.
- a former world champion who flew the glider said: The plane unfortunately
can not be flown to its full performance, because as long as it behaves so
badly.

many modern gliders even accept the flaps to be in intermediate positions
without being in a locked position and the flaps will not move.


wrote in message
ups.com...
- flap handle unlocking in flight and shifting to full positive

I'm curious. How can flaps self-deploy to full positive given in-
flight airflow? Are they somehow balanced?


- too high flap handling forces (more than JAR22 limits)

This one seems to contradict the first one. If it takes a lot of force
to deploy the flaps, how can they self-deploy to full positive?





  #4  
Old June 16th 07, 11:06 PM posted to rec.aviation.soaring
GK[_1_]
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Posts: 30
Default Diana-2 - master-piece or flop?

On Jun 16, 3:44 pm, "BlueCumulus" wrote:
it is not contradictory

- it needs much force to push the flaps to negative position
- when you fly fast through a thermal or turbulence the handle unhooked
and comes fully back into positive position, unless you hold it
permanently
in your hand.
- a former world champion who flew the glider said: The plane unfortunately
can not be flown to its full performance, because as long as it behaves so
badly.

many modern gliders even accept the flaps to be in intermediate positions
without being in a locked position and the flaps will not move.

wrote in message

ups.com...

- flap handle unlocking in flight and shifting to full positive


I'm curious. How can flaps self-deploy to full positive given in-
flight airflow? Are they somehow balanced?


- too high flap handling forces (more than JAR22 limits)


This one seems to contradict the first one. If it takes a lot of force
to deploy the flaps, how can they self-deploy to full positive?



- Strangely enough Mr.Johnosn did not publish these "revelations".

  #5  
Old June 17th 07, 12:06 AM posted to rec.aviation.soaring
Paul Hanson
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Posts: 89
Default Diana-2 - master-piece or flop?



- Strangely enough Mr.Johnosn did not publish these
'revelations'.


I am not taking any sides in the Dianna 2 debate, as
it seems like a hot ship, with a not too shabby track
record to back that up and I do not have rounded enough
info to pass judgment on it. I do want to point out
however, that this thread is about s/n 3 or higher;
Johnson tested s/n 2, the personal Dianna 2 of the
US dealer. I am curious to hear more, both good or
bad (hopefully good though). One can never be too cautious
about believing hype on any product, especially sailplanes,
but I do want to point out that the Poles have a very
good track record when it comes to their ship's performances
and their claims about them. In general they tend to
be very objective, scientific, and accurately stated,
as confirmed by many other Johnson (and other's) tests,
including s/n 2 Dianna II. But lets not stifle further
discussion on the subject.

Paul Hanson
"Do the usual, unusually well"--Len Niemi


  #6  
Old June 17th 07, 04:22 AM posted to rec.aviation.soaring
[email protected]
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Posts: 172
Default Diana-2 - master-piece or flop?

On Jun 16, 5:24 am, wrote:
- flap handle unlocking in flight and shifting to full positive

I'm curious. How can flaps self-deploy to full positive given in-
flight airflow? Are they somehow balanced?

- too high flap handling forces (more than JAR22 limits)

This one seems to contradict the first one. If it takes a lot of force
to deploy the flaps, how can they self-deploy to full positive?


Yeah, I'm curious too. I have an old Speed Astir, and had some trouble
with the flap lock becoming disengaged. It usually happened turning
base to final, and went from full positive to full negative in blink
of an eye. There is considerable force at all airspeeds and conditions
(except a negative "G" push) exerted on the flap control toward the
negative flap setting.

  #8  
Old June 17th 07, 09:00 PM posted to rec.aviation.soaring
tommytoyz
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Posts: 57
Default Diana-2 - master-piece or flop?

" this thread is about s/n 3 or higher;"

There is a very good report on another ship in the US, which I assume
is SN3 or higher and reports nothing of rumors that you are passing
on.

From Bill Liscomb's report on his ship:


Off tow the fun really begins! It
is easy to fly and the roll rate is downright
snappy. As with most flapped ships,
as the flaps go farther down, the adverse
yaw goes up. But at normal climb/cruise
settings it is not noticeable and control
harmony is good. I haven't flown with
other ships very much, so I can't claim
any kind of remarkable thermalling performance.
I do know this thing has
climbed out of situations where my previous
glider, a 304CZ, would have had
problems. The flying weight of the Diana 2
(without water ballast) is about 25 pounds
heavier than the empty weight of the 304CZ! Empty weight of my Diana 2
with instruments, battery, oxygen, etc., is 433 lbs.
Then, there is the glide. Unreal! I'm still having trust issues with
the glide computer. It seems impossible that a 15m ship
has legs like this! The factory provides a nice sheet of linear graphs
showing flap settings for speeds at different wing loading. The
idea with the flap charts is you cut them out and stack them together
with a glue stick. As you dump water, simply peel off charts
until you get to your current wing loading. The correct flap setting
is mandatory to get the best performance from this ship. In
March of 2007, I did get to see what a load of bugs does. I checked
out my black, fuzzy leading edges, then set the glide computer to
20% bugs and did a 30 mile final glide. I got back to Warner very
high, dialed the bugs back to zero, and it showed my actual arrival
altitude.
I've done one flight with water
ballast. I put in 43gallons (344 lbs)
plus another 12lbs in the tail, which put
me at just under 1,000lbs (1102 lbs is
the maximum). This gave a wing loading
of 10.6 lbs sq ft. (the dry wingloading
is about 6.7 lbs sq ft). Once off
tow, the water transforms the glider
into a rocket. I felt like I was strapped
inside a runaway locomotive. I flew on
August 29th, 2006, a great day in So-
Cal, and SeeYou showed two segments
over 170 miles with no turns and average
speeds 113 and 116mph.
Landings are easy. I use the
+21 flap setting rather than the +28
because of the wind we usually have at
Warner Springs. This setting also increases
aileron effectiveness while
dealing with the normal crosswind
shear, thermals and turbulence on final.
Wheel landings are the norm - touch
down, add full spoilers, put flaps full
negative, hold the tail off, roll to a stop.
The Diana 2 is small and light, both in the air and on the ground. It
is a total blast to fly. Soaring in Southern California is
unique in that a pilot can encounter several different air masses in
one flight. Without water ballast, the Diana 2 is very capable of
handling these conditions. It does very well in small, weak thermals
as well as the big rowdy stuff, and has an amazing glide over a
wide speed range. When it gets good, simply add water. Lots and lots
of water...

  #9  
Old June 17th 07, 10:20 PM posted to rec.aviation.soaring
Udo
external usenet poster
 
Posts: 132
Default Diana-2 - master-piece or flop?

Thanks for the report.
I do not know were people pick up those ideas.
I did fly a few times with and against the Diana and I was very much
impressed. I also did sit in the cockpit and I was not able to get
comfortable.Other then that I was very much tempted. Instead I got an
other glider.
Udo

On Jun 17, 4:00 pm, tommytoyz wrote:
" this thread is about s/n 3 or higher;"

There is a very good report on another ship in the US, which I assume
is SN3 or higher and reports nothing of rumors that you are passing
on.

From Bill Liscomb's report on his ship:


Off tow the fun really begins! It
is easy to fly and the roll rate is downright
snappy. As with most flapped ships,
as the flaps go farther down, the adverse
yaw goes up. But at normal climb/cruise
settings it is not noticeable and control
harmony is good. I haven't flown with
other ships very much, so I can't claim
any kind of remarkable thermalling performance.
I do know this thing has
climbed out of situations where my previous
glider, a 304CZ, would have had
problems. The flying weight of the Diana 2
(without water ballast) is about 25 pounds
heavier than the empty weight of the 304CZ! Empty weight of my Diana 2
with instruments, battery, oxygen, etc., is 433 lbs.
Then, there is the glide. Unreal! I'm still having trust issues with
the glide computer. It seems impossible that a 15m ship
has legs like this! The factory provides a nice sheet of linear graphs
showing flap settings for speeds at different wing loading. The
idea with the flap charts is you cut them out and stack them together
with a glue stick. As you dump water, simply peel off charts
until you get to your current wing loading. The correct flap setting
is mandatory to get the best performance from this ship. In
March of 2007, I did get to see what a load of bugs does. I checked
out my black, fuzzy leading edges, then set the glide computer to
20% bugs and did a 30 mile final glide. I got back to Warner very
high, dialed the bugs back to zero, and it showed my actual arrival
altitude.
I've done one flight with water
ballast. I put in 43gallons (344 lbs)
plus another 12lbs in the tail, which put
me at just under 1,000lbs (1102 lbs is
the maximum). This gave a wing loading
of 10.6 lbs sq ft. (the dry wingloading
is about 6.7 lbs sq ft). Once off
tow, the water transforms the glider
into a rocket. I felt like I was strapped
inside a runaway locomotive. I flew on
August 29th, 2006, a great day in So-
Cal, and SeeYou showed two segments
over 170 miles with no turns and average
speeds 113 and 116mph.
Landings are easy. I use the
+21 flap setting rather than the +28
because of the wind we usually have at
Warner Springs. This setting also increases
aileron effectiveness while
dealing with the normal crosswind
shear, thermals and turbulence on final.
Wheel landings are the norm - touch
down, add full spoilers, put flaps full
negative, hold the tail off, roll to a stop.
The Diana 2 is small and light, both in the air and on the ground. It
is a total blast to fly. Soaring in Southern California is
unique in that a pilot can encounter several different air masses in
one flight. Without water ballast, the Diana 2 is very capable of
handling these conditions. It does very well in small, weak thermals
as well as the big rowdy stuff, and has an amazing glide over a
wide speed range. When it gets good, simply add water. Lots and lots
of water...



  #10  
Old June 17th 07, 11:36 PM posted to rec.aviation.soaring
BlueCumulus[_2_]
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Posts: 37
Default Diana-2 - master-piece or flop?

Maciek wrote: If one of your ailerons pins out, or your flaps aren't
locked at their position - they will all deploy up. It is impossible that
the flaps are balanced that much ....


I do not agree with that.
It depends on the aerodynamic and kinematics design of the flap system.

The ASW27 does not show any tendency to change flap settings between
+2 and -1 which covers a speed range of 80-180km/h. The same I was
told to be the case for the ASW26. You can have the flaps in any inter-
mediate position and it will stay there. you can move the flaps to any
setting with two fingers (except -2 and Landing position).

As said before the prototypes of the Diana-2 have the wing position about
5cm (2") more tailward than this first "Serial Machine". Why the wing-
position was moved forward is not clear but confirmed. After such a
significant change I would rather call it a prototype as well. The handbook
as well did not show the new drawings and figures for the CG calculations.
The glider was month too late in production and delivered in a hurry after
just one test flight. This Diana-2 with production number 3 seems to be a
different plane in regards of flying behavior than the prototypes.
That's why I was wondering if anyone might have flown number 4.
__________________________________________________ ______

"Maciek" wrote in message
...

wrote:

Yeah, I'm curious too. I have an old Speed Astir, and had some trouble
with the flap lock becoming disengaged. It usually happened turning
base to final, and went from full positive to full negative in blink
of an eye. There is considerable force at all airspeeds and conditions
(except a negative "G" push) exerted on the flap control toward the
negative flap setting.


finally someone imaginative... There is a pressure difference betweene the
upper and the bottom surface of the wing, thanks to whitch our gliders can
fly (if there is enyone who doesn't know that...). If one of your ailerons
pins out, or your flaps aren't locked at their position - they will all
deploy up. It is impossible that the flaps are balanced that much, to
overcome the pressure difference and deploy to positive - especially in a
glider weighting 185 kg.

Mat



 




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