Diamant 18m

I'm looking into buying an 18m Diamant. There doesn't appear to be much
info about this particular model on the net other than the BGA's tech
sheet and a few odd references. I have no issue with it being flapped
etc. I wondered if anyone had experience with the 18 metre Diamant or
new of a url for more info. I'm told Jane's World Sailplanes has some
good info but other than that nada.

here's hoping

Phil

Phil,

I havent flown one myself but you may find some information
on:

www.sailplanedirectory.com

Hope this helps,

JR

At 16:48 28 March 2006, Phil Collin wrote:
I'm looking into buying an 18m Diamant. There doesn't
appear to be much
info about this particular model on the net other than
the BGA's tech
sheet and a few odd references. I have no issue with
it being flapped
etc. I wondered if anyone had experience with the 18
metre Diamant or
new of a url for more info. I'm told Jane's World Sailplanes
has some
good info but other than that nada.

here's hoping

Phil

I had one a long time ago. See this thread on gliderforum:

http://www.gliderforum.com/thread-view.asp?threadid=729

John Galloway




At 18:12 28 March 2006, Jono Richards wrote:

Phil,

I havent flown one myself but you may find some information
on:

www.sailplanedirectory.com

Hope this helps,

JR

At 16:48 28 March 2006, Phil Collin wrote:
I'm looking into buying an 18m Diamant. There doesn't
appear to be much
info about this particular model on the net other than
the BGA's tech
sheet and a few odd references. I have no issue with
it being flapped
etc. I wondered if anyone had experience with the 18
metre Diamant or
new of a url for more info. I'm told Jane's World Sailplanes
has some
good info but other than that nada.

here's hoping

Phil

Contact Ray Poquette. He loves the Diamant 18.

Ray is "Thermo-Tec", and his number is in the classified section of
"Soaring".

Mike


phil collin wrote:
I'm looking into buying an 18m Diamant. There doesn't appear to be much
info about this particular model on the net other than the BGA's tech
sheet and a few odd references. I have no issue with it being flapped
etc. I wondered if anyone had experience with the 18 metre Diamant or
new of a url for more info. I'm told Jane's World Sailplanes has some
good info but other than that nada.

here's hoping

Phil

I had a Diamant 18 from 1974 - 1983. I had about 750 and some odd hours
in it. The info from Art on the Glider Forum is good. The 18 had an
AD on the spar stubs that limited your VNE until it was accomplished.
Most of the ones around had already had the earlier ADs on the flap
counterweights and the rudder damper done already by the factory which
had a representative travel around and fix them (Fred Jiran). I flew it
for a long time and sold it without ever complying with the spar stub
AD, because in normal flying, it was rarely necessary to go that fast
anyhow. The factory, FFA from Switzerland was still supporting it and
provided a kit to accomplish the spar stub AD.

It's a real floater for a glass ship. It has a very good L/D, but it
comes at a relatively slow speed. It looks a lot like an ASW-12 and has
a similar max L/D, but the whole performance curve is shifted over to
the left, so everything happens about 10mph or more slower than the
ASW-12. But compared to the 12, it's a much easier and safer ship for
ordinary mortals to fly. It has a lot of washout in the wing, which
I think is one of the reasons the stall/spin behavior is very good, but
this hurts it's high speed performance. This is both good and bad. I
think it could still stay up on weak days better than any ship I can
think of, even today, except maybe the LightHawk. It would make an
excellent contender in the "micro-lift" arena, even today. It has a
very slow stall speed and landing speed. You can get it down below 30
knots when thermalling. The real expert on Diamants is Dan Pierson.
He used to fly his with as much or more than 70 gallons of water.
This would put him even or even better than the ASW-12 and
tantalizingly close to some of the big open ships like the Nimbus 2 at
the time. Dan still has his 18 and has extended the wing to 19 meters.
He had taken up "open cockpit" Diamant flying with the aft part of the
canopy removed the last time I talked to him. I don't think you would
want to land it gear up, as the fuselage is actually a foam sandwich
construction and the amount of glass over the foam is pretty thin and
would not take much abrasion. Once you got into the foam, your hind end
would be scraping the surface in very short order, I think.

The rather small size, of the landing gear definitely comes into play
when you fly it with that much water. It was a real big risk to take
off on that gear with that kind of weight. You could only do it at
carefully checked runways with no chance of any holes or bumps, and
even then, it was a big risk. With no water ballast, the gear is
adequate, although on the small side - I think it used the same size
hub and tire as a Libelle which was a much smaller ship. I never flew
mine with more than 45 gallons. I considered the 25 gallon difference
between me and Dan Pierson as my safety factor, since no formal
structural analysis of flying with that much water had been done :-)
The wings are big and one piece, but not really all THAT heavy, I mean,
esp. compared to a Nimbus 2 or ASW-17 inner panel. The main pin on
the spar stub had to be lined up just right with the bearing on the
root rib of the other wing, or it just would not go together, and it
was a rather bluntly rounded pin, so it was very difficult to visually
tell if it was lined up right. I found that it was easier to do it by
feel out on the wingtip. There was a certain "sweet spot" and you
could with practice find that pretty easily. When it was lined up in
the sweet spot, it would just fall together very easily. But if you
were not in the sweet spot, no amount of force would help. It had a
rigging lever similar to a Libelle, but that was totally useless.

As far as flying qualities, the flaps are very nice and very effective
for decreasing landing speed and help give you a better view over the
nose (your feet) when landing. The dive brakes are also very effective
and combined with the landing flap position and the excellent view, and
the very low stall speed, make it a very nice ship to land. The
reclining position is very comfortable once you get used to it. It is
very narrow in the cockpit, but pretty long, that's pretty obvious just
from looking at a picture of the ship. The rudder is very heavy on
the 18. That is really because it has a very large area, and is driven
by a pushrod system and the lever arm that drives the pushrod in the
nose is only a few inches long, so the amount of force required from
your feet can be quite high just due to the mechanics of the short
lever arm. The all flying tail is quite sensitive, but not any more so
than a Nimbus 2 or a Std. Cirrus. The ailerons can have a lot of
friction, and the forces are high compared to some other designs. The
ailerons use these drivers that have ball bearings with races at 45 deg
angles to translate the lateral motion of the pushrods to an up and
down motion. These can get dry and were usually not accessable because
the fittings they attach to the wing by had been filled over with
filler. But you can remove the filler and take them appart to clean
and grease them. I used to try to spray a light weight lubricant on
the bearings but then you get more dirt in there and you can't get in
there and clean it out without taking them apart.

Alex Caldwell
Tulare,CA

phil collin wrote:
I'm looking into buying an 18m Diamant. There doesn't appear to be much
info about this particular model on the net other than the BGA's tech
sheet and a few odd references. I have no issue with it being flapped
etc. I wondered if anyone had experience with the 18 metre Diamant or
new of a url for more info. I'm told Jane's World Sailplanes has some
good info but other than that nada.

here's hoping

Phil

My first glider was a Diamant 16.5M, extended to 17.2M. Except for being
a bit sensitive in pitch, It was easy to
fly, docile and climbed great. The pilot seating is very reclined and
this required some getting used to. Rigging can be challenging...bring
friends. Don't fly it with white shoes though because the highly curved
canopy magnifing the reflection and the movement of your feet can be
very distracting.

Paul




phil collin wrote:
I'm looking into buying an 18m Diamant. There doesn't appear to be much
info about this particular model on the net other than the BGA's tech
sheet and a few odd references. I have no issue with it being flapped
etc. I wondered if anyone had experience with the 18 metre Diamant or
new of a url for more info. I'm told Jane's World Sailplanes has some
good info but other than that nada.

here's hoping

Phil

I owned a share of a Diamant 18 from 1974 to 1979.
It was my first glass glider and I found it relatively
easy to fly with few vices. There was a mod to the
all moving elevator that some UK Diamants had -- ours
did not. The mod was a small extension to the middle
aft part of the elevator and was intended to increase
the pitch stability. Without this mod the pitch stability
is rather poor and in fact stick forces REVERSE at
high speeds. To make this clear, the faster you fly,
the more you need to hold the stick back! Very weird.
If you let go the glider would (presumably) go into
an immediate bunt.

However we never bothered to have the mod done and
I guess that shows that we did not have any qualms
about the handling (or were we young and foolish?).

As others have said the brakes are excellent and extend
from the top and bottom wing surfaces.

The canopy opening mechanism and cockpit shape are
very unconventional but caused us no problem. A previous
owner did suffer a partial opening of the canopy in
flight and flew the rest of the flight one handed while
holding the canopy on with the other!

I don't remember any problems with the rectractable
U/C. However I did manage to bend the axle in a firm
landing. So I would say that the U/C is strong enough.

Ours was landed wheels up at least twice. Once on
a tarmac runway with a cine camera strapped to the
underside. This caused a fair amount of damage. The
second time I was the pilot and got away without any
damage on a soft hay field.

I don't think I have flown a better glider for weak
wave. However a modern standard class glider will
outperform the Diamant in thermal cross-country tasks.