Lark IS28B2, info request

1. What is service life, factory or imposed?
2. How would you rate it as a training glider, ab-initio to
intermediate to advanced?
3. What is current parts availability?
4. Strong points?
5. Weak points?
6. Maintaince, easy to difficult?
7. Are they US ATC'd?

I've had experience with a dozen two seaters, but have missed out on
this one and need the info. Replies to r.a.s or e-mail are okay.

Thanks,

Francis

Gary

Not sure, we have 2 x IS28's & an IS-30 2 seaters, about 15 years old
I figure at this stage. Gliding Club of Victoria (Australia) has
quite a few of these guys.

Noted the followups on spinning, yes this is true. But the IS30 will
spin 'quicker'. The air brakes on the IS28 are not as effective as on
say a K13. They are 'harder' to land than K13 etc. Safe to say that if
you can land these guys you can land a 'lot' of gliders nicely.

We use them as the main training aircraft in our fleet.

> 4. Strong points?

Strong, takes heeps of abuse, good X country two seater with GREAT
penetration not bad L/D.

> 5. Weak points?

Around the tail/elevator area, there has been some weakness discovered
where you can 'twist' the elevators in opposite directions with
a fair amount of play. There are ways of fixing this.

Not much fun rigging/derigging.

/daveb

2. This is definitly an intermediate training glider. It has a good mass and
the pilot needs to know what he does to control it. It is definitly not in the
Blanik class of glider for example, its reactions are more like a glass ship.

3. In Canada at least the parts a relatively easy to get as there is a local Lark
dealer.

4.Strong points, looks, performance 34 or 36:1, all metal can sleep outside
good mass so good penetration, easy access for maintenance.

5. Wheel fork is weak, heavy, needs a team of 6 to 8 to disassemble. Eyebolts for ailerons
porly manufactured and needs to be inspected and replaced.

6.Maintenance is easy.

7 I do not know. It is available in Canada.

Jean Lapierre

That has been my experience also. I have "snap rolled" (a very slow event, given the
long wing span) out of tight thermals on several occasions -- watch the airspeed. The biggest
problem we had with the Lark was the difficulty in ground handling caused by the heavy wieght
of the plane.

On the other hand, it is comfortable and good vis.

I found that the controls were not well balanced, and the stick was too long. Alerons took too much effort
and the rudders were touchy.

Another common problem -- make sure that the brakes are locked before takeoff--air pressure will suck out
the brakes on takeoff and really hurt (our anemic towplane) performance.

Francis Govers
fxgo...@tasc.com

The latest factory recommendation that I have seen is in our manual as
a mandatory service bulletin dated in 1985,
stating an updated "total safe life" to 10,000 hours or 30,000 landings.
Additionally, a "total service life" updated to 20 years. That
part was news to me, as we have a 1978 model. Our AI sees these as a
recommendation based on an estimated use rather than an absolute
restriction (USA). I guess that makes me wonder.

Our club uses this as an intermediate trainer, to advance a pilot to
our 1-36. For that it works well. Cause the Lark or 1-36 will spin
if you incorrectly recover from an incipient stall in a turn/thermal.
Wrong input (pro-turn rudder or anti-turn aileron) = spin entry.
Unlike ASK-21, Grob 103, SGS 2-33's that I have flown.

The US Lark dealer has been able to get the Lark-unique parts, but
refers us to Tost dealers for the release, wheel, gas shock.

>4. Strong points?

As has been stated, good 'legs' (penetration, weight) for x-c, all metal.

The shock makes for comfortable landings on rough runways.

Flaps. No one has mentioned that the flaps reduce thermaling speeds
and landing speeds. The flaps have a negative setting for high speed.

>5. Weak points?

Weight seems to be the major deterent to getting a crew. Although, a
former Lark owner gave us his portable crane/winch and wingstand. The
crane is a 4 foot (1.5 meter) pipe with a hand-cranked boat trailer
winch. He said that he
(in his +70's) and his 110 pound wife could disassemble his Lark with
two people in 45 minutes. I'm not sure about the time, but I'm sure
the right two people could do it. Our club thinks 5 makes it work
easy enough.

The spoilers aren't as effective as G-103 or ASK-21.
The stick is long because the aileron forces are big at high speed.
But yes, the controls aren't well balanced. Coordination is
rudder-limited.

Yes

Have fun! We really like ours.
John

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Make sure that the spoilers are properly adjusted. The Lark is
supposed to have a 15-22 pound pull to unlock. Spoilers that 'unlock'
by themselves might also have that problem.

If you stall, or fly uncoordinated, yes, it will spin. Makes one an
'honest' flyer. (honestly, I thought the yaw string was straight!)

Thanks for your input and thanks to others who've responded via
this group and e-mail.

This is disconcerting. I hardly feel like gambling on buying a
glider that may be "lifed" in 1997, though it'll have less than 1000
hours on the airframe.

It brings more questions to mind.

How do we approach this? SSA to FAA? SSA to Manufacturer?

If the current legislation (18 year product liability limit) passes,
will either become more lenient?

Will the glider lose it ATC at 20 years and be limited to
Experimental only?

Has the EAA any information on similar power aircraft scenarios of
factory "total service life" and FAA dispositions?

Francis