Jonker 18 meter sailplane

[Greg Arnold]

I have been looking at the website for this new sailplane --
http://www.jonkersailplanes.co.za/.

One photo has this caption: "The post curing oven is almost completed.
All components must be post-cured at 60°C for minimum 12 hrs for the
epoxy to achieve its LBA approved specifications."

I know that high-tech sailboats are post cured, but it was my impression
that sailplanes were not, and this was a reason that some have problems
with subsequent changes in wing shape.

Is Jonkers using a better technology that everyone else, or is
post-curing already done by other manufacturers?

[[email protected]]

Greg Arnold wrote:
>
> Is Jonkers using a better technology that everyone else, or is
> post-curing already done by other manufacturers?

All gliders that I kow of are post cured to some extent. The epoxy
resin does not reach it full potential strength untill it has been post
cured.

Robert Mudd
Moriarty, New Mexico

[Greg Arnold]

wrote:
> Greg Arnold wrote:
>> Is Jonkers using a better technology that everyone else, or is
>> post-curing already done by other manufacturers?
>
> All gliders that I kow of are post cured to some extent. The epoxy
> resin does not reach it full potential strength untill it has been post
> cured.
>
> Robert Mudd
> Moriarty, New Mexico
>

I see on the DG website that DG post-cures at 35 C (95 F), while Jonkers
claims to post-cure at 60 C (140C). I just looked at a book on sailboat
building, where one builder says he post-cures at anywhere from 176 F
(due to a limit in a racing rule) to 200 F.

[Mike Lindsay]

In article >, Greg Arnold
> writes
wrote:
>> Greg Arnold wrote:
>>> Is Jonkers using a better technology that everyone else, or is
>>> post-curing already done by other manufacturers?
>>
>> All gliders that I kow of are post cured to some extent. The epoxy
>> resin does not reach it full potential strength untill it has been post
>> cured.
>>
>> Robert Mudd
>> Moriarty, New Mexico
>>
>
>I see on the DG website that DG post-cures at 35 C (95 F), while Jonkers
>claims to post-cure at 60 C (140C). I just looked at a book on sailboat
>building, where one builder says he post-cures at anywhere from 176 F
>(due to a limit in a racing rule) to 200 F.

Gives an entirely new meaning to the expression "hot ship" doesn't it?
--
Mike Lindsay

[Jack[_4_]]

I know that my PIK-20 was actually built in an autoclave. After 30
years, I still have no spar bump or dip. The unfortunate piece of that
is that the molds warped and the wings are a touch too thick. I believe
Sparrowhawks are cured at above 300 deg. f. if I read the info
correctly.

Jack Womack