Hostetler 40% GeeBee Model Z

[Phil Clark]

Work progressing on the canopy & cockpit hatch patterns........a final 600 rub down followed by a gloss colour coat & a polish and they are good to have the moulds laid up.

Also here are the 2 fairing patterns that fair the undercarriage leg fairings into the underside of the wing.

[Phil Clark]

The fin (or lame excuse for one!!!) is also done, as are the hard points for the rudder strap hinges & the tail plane strut & bracing wires.

[Phil Clark]

Canopy & cockpit hatch patterns are complete and moulds have been laid up.

The finished female mould for the canopy is then used to pour an aluminium powder filled PU resin vac-form tool. This is completely grain free and temperature stable so gives excellent results when crystal clear mouldings are required. The final tool is not solid but has an HD foam insert (bonded to the balsa support bars) that gives a 1/2 - 3/4" wall thickness of resin...........more cost effective on resin + doesn't create quite as much heat as it cures in the glass mould.

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[Phil Clark]

Moulds for the removable panels at the roots of the tail plane.........here already cured, removed, trimmed with a ply frame added to improve mould stiffness. These moulds were laid up over plasticard panels tack glued over the appropriate areas.

The removable glass panels laid up in 2 layers of 160g twill weave cloth with 2" glass tape around the edge to thicken the edges for the fixings. Again, the panels have been removed and rough trimmed in this shot

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[Phil Clark]

The huge wing fairings are also pretty much complete.

The centre & rear sections are from 1/8" balsa with lite ply formers. The front section is from HD foam with a skim of epoxy & ultra light fairing compound before a thorough sanding & glassing in 48g cloth and L285 resin. Once the glass is cured, and minor undulations or imperfections can be filled and blended in without fear of under cutting surrounding soft balsa.

Evident here is the fact the fairing is not 1 complete smooth curve. The centre section is only single curvature from just below fuselage centreline with only a slight double curvature across the top of the wing section. The fairing has a defined kink in it where it's joined to the double curvature rear section.

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[Phil Clark]

Canopy hatch mould complete & the hatch laid up, out of the mould & rough trimmed to size. Peel ply used internally to aid bonding of the internal structure to the hatch + a 1" carbon tape added around the front edge as the hatch is very thin ahead of the canopy.

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[Phil Clark]

Turning to the tail skid, the full-size (as far as we can tell) has a free castering skid.........useless on a large model so we've opted to fit a steerable kid. The finished tail skid will be finished with a moulded glass streamlined fairing, but the basic component is based around a 16mm st/st thin walled tube with a 6 SWG piano wire shaft running on a pair of machined bronze bushes A tiller arm is attached to the top end of the piano wire shaft with closed loop cables to the rudder servo. The 16mm tube shaft is silver soldered to a 3mm steel mount plate the skid is silver soldered up from hand cut brass & st/st plate parts......

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[Phil Clark]

A fiddly session of cutting (Diamond wheel in Dremel) and filing had all the moulded glass louvers ready to fit into the forward fuselage.

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[Phil Clark]

The flying & landing wire attachment points + fairings for where the landing gear fairings meet the underside of the wing are all covered over with fairings of various shapes & sizes..........once the laser cut metalwork for flying/landing wires was trial fitted, patterns were made of all of the various fairings (the basic glassed balsa pattern for the carb intake scoop that's fitted under the nose is also shown in photo #1) before a mould was made & all the fairings were made in epoxy glass (16 individual parts in total)

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[Phil Clark]

Bit more detail stuff..........the internal tubular steel framework of the full-size has to be replicated inside the cockpit area as it's all visible with the canopy hatch removed. So with the internals tidied up, the framework (dry fitted only here) is added in 6mm carbon tube.

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[Phil Clark]

More metal work in the form of st/st streamline section tail plane struts with 1mm st/st plate end fittings silver soldered. Shown here after clean up but prior to sand blasting & etch priming. Spruce hard points in stab & fuselage are all bushed in brass tube to prevent wear & crushing when nipped up.

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[Phil Clark]

Moving to some initial finishing work, the cowl is flatted & primed in grey epoxy primer inside & out + after all forward fuselage louvers are fitted & feathered into the fuselage, the complete front end is glassed in 48g cloth & L285 resin.

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[Phil Clark]

A brief interval from winter grey & rain and it's outside in the sun for a few progress pics.......

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[Phil Clark]

Back to surface prop on the front end.......after a 2nd brushed coat of resin to fill the cloth weave and a course 80 grit rub down, it's into the primer sand, primer sand phase.......3 coats of primer and 3 rub downs gradually working finer & finer (taking most of the primer off each time) and we're ready for a final 600 grade rub down before we start adding the various raised panel edges & the multitude of fixings & fasteners.

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[Glenn Masters]

That sir - is a masterpiece !! and its one of my favourite genres of 1930s buttock-clenching-prop-snapping-somersaulting-hooligan-mannered aircraft ! Will you be able to make available any of your countless moulding details ? particularly the engine baffle pattern, louvre details and flying wire bezels etc ?

[Phil Clark]

Hi Glenn

Thank you....glad you approve!!

Re:- availability of glass mouldings.......yes, they will all be available a little later down the line (you're not the 1st to ask)

Cheers

Phil

[Phil Clark]

It's been a long time since I've shown any progress with the big GeeBee Z, but we've not been idle. Alongside the GeeBee, multiple other projects have been completed over the past 6 months.........these include the long term renovation of my 1:3.5 scale Messenger, a Nijhuis Vampire, the repair/renovation of a Ziroli DC-3 + my colleague John's 1/5 scale Ed Newman Storch........all bar the DC-3 have successfully flown and the DC not far behind. We've also done a couple of ARTF bashes (Hanger 9 60cc P-51 + a Flying Legends 1/4 scale DH.60 Moth).......plus a commercial UAV project that I'm unable to post photos of yet on request from the client.

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[Phil Clark]

So.......back to the GeeBee................we're no more than a few weeks away from completion, so these images go back a while.

Paintwork......all done with Klass Kote 2-part epoxy paints with custom paint masks from Flightline Graphics.

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[Phil Clark]

With a 470mm diameter cowl, even a Moki 400 looks small and didn't 'fill' the cowl (it's a scale model & it looked all wrong)..........so..........we need a dummy Pratt & Whitney 'Wasp Junior'.

This is built around a moulded glassfibre crankcase, cylinders built from 'stacked' laser cut styrene parts (over 100 per cylinder) + a multitude of different resin cast & tubular aluminium/brass parts.......A LOT of work, but hopefully very convincing. It's not 100% finished in the photos below.......various small bits & pieces still to add.

And before anyone ask 'won't this blank off too much cooling air for the Moki?'.........all 9 cylinders are 'hollow' allowing air to pass straight through them.

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[Phil Clark]

The colour of the cowling artwork has proved a tricky one..........some references say yellow & blue.......others off white & red. The docs we've used for this model state white & red so we've gone with it.......

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