Re: Weight Build-Up of Q1


There are a lot of things in life that would be NICE to have, but we are25+ years down the road
in the building process, nobody has yet done what you think would be nice and all the blabbering
about it wont make it happen. This late in the game you wont get enough data to make anything
statistically significent. It would have been NICE if you wouldve been around 20 years ago with your

-----Original Message-----
From: Rob de Bie <>
To: Q-LIST <>
Sent: Mon, Jun 25, 2012 1:32 pm
Subject: Re: [Q-LIST] Re: Weight Build-Up of Q1

I think it would be very nice to have a detailed weight breakdown. It
would allow the builder to see whether he's building his component
too heavy, and by adding up component weights, he could also check
the weight of the airframe being assembled progressively.

The 100 grams I mentioned was (unfortunately) not the deviation from
the predicted total weight of 28 kg. It was the error on the
calculated *balance weight* in the nose (typically 400 grams). I
mentioned it as an example how difficult it is to keep track of all
component weights and location during construction. Although I really
tried, I never was able to predict the balance weight better than 100 grams.

About vacuum bagging a 'Rutan style' wing: I once calculated how much
the foam would be compressed under full vacuum, and I was surprised
how much it was! I don't recall the exact number, but it was a few
percent. That would probably lead to wrinkles in the laminate,
because the foam is also compressed in chord and span directions.
Maybe it was done with a light vacuum?


At 00:47 20-06-2012, you wrote:
, Rob de Bie <robdebie@...> wrote:

Thanks for the data! Maybe it can be compared (one nice day) with the
theoretical weight of these components, adding up the foam weight,
skin weight, spar weight, etc.
Having built with the Rutan style construction and watched several
others do the same process,and with the variability of the amount of
epoxy contained in the layup and subsequent finishing, and having
perused several similar projects,it is unlikely that any weight will
predict within ten percent of minimum.

Hand lay up projects that use vacuum bagging with bleeder sheets
predict much closer to minimum weights. prepreg parts of course are
much closer. 100 gram out of 28000gram is darn good!

A look at gene's carbon Q1 which was hand layed and vacuum bagged
with bleeder sheets, indicates just how light and predictable a hand
layed Q1 can be made.

My conjecture is, if the original Q1 could have been built as light
and as conforming to shape as the carbon Q1, even the Ohnan powered
version would have many more examples FLYING today...



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