> Vacuum bagging is no problem, we do it on almost every part we make.
> I don't think i'm too worried about fire personally. The general layout
> is important.
> The spacers need to be inserted prior to thermal cure. The mold would
> need to have
> the sides needed for a motor mount built in. This part might be best
> done male-molded.
> The vacuum bagging would give a super finish anyway.
> Bill
>
> Good idea on the built in motor mount. We considered this
> a long time ago sand cast in aluminum but the heavy weight was
> discouraging.
>
> Carbon fiber would be another matter entirely.
> Here are a few old dwgs. It would have to be redesigned
> for carbon fiber. I'll work on it.
>
> -- Paul Lamar ...No rotor no motor.
>
> Paul,
> The motor mounts need not be actually made from the mold. The flat
> sides George did for the aluminum BH would work too. That said if the
> shape could be kept somewhat simple it would be lightest to mold them
> in. A thin rib is difficult to set up in the mold of course. A fluted
> shape is better while still being removable.
> Bill
Bill,
I was just thinking about stiffeners and how they might be incorporated
integral to the design. I don't think the stiffeners need be high
considering the stiffness of the carbon.Perhaps like the Mazda aluminium
housing with low wide ridge, (is that what you mean by fluted shape ?)-
perhaps even foam filled to keep the weight down if you wanted a smooth
inside wall. Any number of ways of doing it.
George ( down under)
George,
What I mean by fluted is more of a half round of a tube on the surface
or indented into the housing. Remember if you have a narrow opening you
must place the fiber (usually a prepreg with carbon) down into it. It is
also best if you can get your vacuum bag in there to debulk the fiber of
the resin. One way we have done stiffeners is to mold them as a separate
part with a wide flange and then do a bond and post-cure using the base
resin as a binder. almost as strong as doing it in one shot. You want
the indents to be almost as wide as the palm of your hand. You can pack
fiber tow into a small groove but it can be iffy an how good that will
come out. Exeothermic reactions when curing the fiber are a problem as
well. The cure temps are around 275 deg. F and the resing will self heat
when it "kicks off" so you need to be careful. I've attached a file
showing fluting. Just a reference, not to scale really.
Bill J
Hot tip resin. Probably cost you and arm and a leg.
http://www.cytec.com/business/EngineeredMaterials/HighTempMaterials.shtm
Paul Lamar
------------------------------------------
Cytec Engineered Materials
Product Information
High-Temperature Materials
Cytec Engineered Materials is the industry leader in the
development and production of high temperature prepreg and
RTM resin systems.
Cytec Engineered Materials' high temperature resin
technology includes BMI (bismaleimide) and polyimide technology.
These resin systems provide service temperature performance
ranging from 400° F (BMI) to 680° F (AVIMID).
Our BMI products include prepregs, RTM resins and molding
compounds and are in use on a variety of programs such as
the F-22 Raptor, the C-17 Globemaster and the F-35 Joint
Strike Fighter. Cytec also offers a film adhesive, FM 2550
that is designed for use with BMI prepreg systems.
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