Hostetler 40% GeeBee Model Z

[Phil Clark]

With the wings essentially complete and the main fuselage done, mounting the engine & cowl plus undercarriage & spats is next, so time for some moulding...................

After glassing and basic surface prop work, cowl & wheel spat patterns have been finished in 2 coats of gloss black Klass kote epoxy before a flat down to 1200 and a polish with a medium & fine grade cutting compound.

Once set up in parting boards, 6 coats of Mirror Glaze release wax was applied before a heavy coat of black epoxy gelcoat was brush applied. The moulds are laid up with West epoxy, 1 layer of 100g cloth, 3 layers of 200 & a final layer of 100g. The mating faces had an additional 4 layers of 100g cloth to increase thickness/rigidity where the 2 halves of the mould will be bolted together.

[Phil Clark]

Strut fairing patterns & mould.

[Phil Clark]

Moulds released, trimmed and ready for waxing.......

[Phil Clark]

Tail surfaces built after much modification to the terrible Hostetler plans. First off that stab wasn't even symmetrical......5-6mm longer on one side than the other + the rib spacing wasn't accurate to our scale 3-views. With all that corrected, the basic structure has cyparis front & rear spar & diagonals with laminated balsa LE and control surface TE's with balsa ribs & cap strips. We're also incorporating scale 'strap' type hinges rather than conventional pin type hinges. Cyparis hard points are added with brass tube inserts for the bracing strut/wire fixing points.

[Phil Clark]

Wings & tail surfaces covered in Diatex 1000 + Skycraft fabric cement & Rand-o-Proof tinted non-tauting nitrate dope. Two 50/50 thinned coats have been brush applied to partially seal the fabric. Simulated rib stitching + pinked tapes will go on next before a further 2-3 coats of spray applied dope prior to painting.

The epoxy glass cowling has also been made.......very pleased with the end result following the pattern/tool making work.......even a Moki 400 looks tiny compared to this at almost 480mm diameter!!!

[Phil Clark]

Engine re-installed & cowl mounting complete.

6 mounting lugs are bonded & dowel pegged off the firewall. A corresponding ring is Hysol bonded inside the cowl and the 6 fixing bolts are accessed from the rear through the gap between the fuselage & cowl so no cowl fixings are visible.

A baffle plate has also been fitted blanking off all inlet area other than that of the cylinders so all incoming air is forced directly past the engine.

[Phil Clark]

Detailing of the wing panels is also underway..........we've been in contact with the builder of the flying replica of the 'Z' in Florida and from dimensions he's given us off the full-size, we've had the correct width Solartex pinked tapes cut by Mick Reeves, so we know from photo reference they are in the right place + are exactly the right size. Simulated rib stitching under the pinked tapes has been reproduced with a narrower strip of Solartex with cotton strands tacked underneath.

Port upper surface pictured......

[Phil Clark]

.....and the port underside......

[Phil Clark]

Diatex covering + rib stitching & pinked tapes now complete on tail surfaces & ailerons. Two brush applied coats of 50/50 thinned non-tauting Nitrate dope have been applied & we're now part way through a further 3 sprayed coats.

The 1st of the huge wheels spats has also been laid up, here shown still wet prior to trimming (when green) & joining whilst still in the moulds.

[Alan Cantwell 1131]

More than a tad stunning Phil, cant wait to see it in paint

[Phil Clark]

Thanks Alan.......with the Dart nearing completion, the GeeBee will be our main project for the next couple of months, so it'll be progressing pretty fast from here on in.

Phil

[Peter Siggins]

Hi Phil ,
Two stunning builds.Just curious with the Convair water dumping system - how do you compensate for the CG change on the take off run?
Massive project - good luck with the testing

Pete

[Phil Clark]

Haven't got that far yet Pete.......there is still 10-12 months to go with this project before any significant testing is done, so there is a huge amount of work still to be done. With the pattern making work almost complete.....the pattern is then to be 3D scanned to generate a CAD model that will be used to design all of the internal structure. Once scanned, the patterns will then be sent to the tooling company who will be making all of the moulds. Another company with then be manufacturing all the composite components from these moulds prior to the 'kit' returning to The Little Jet Company for final assembly & fit out. 2-3 other companies are also involved in the design/manufacture of the skis and the hydraulic retraction mechanisms, so as you can see, it's a vast undertaking by all involved.

Phil

[Phil Clark]

1st of the wheel spats out of the mount ready for trimming & clean up. 2" carbon tape has been added between layers 2 and 3 of the 200g glass cloth to increase rigidity.

[Phil Clark]

This is the pattern for the forward fuselage louvers (2 blocks of 4 on each side of the upper fuselage behind the cowl & 1 block of 3 on each side below the LE of the wing just behind the cowl).

A master was made for 1 of the 4 negatives before a silicone mould was taken and 4 identical parts cast in fast cure PU resin. Once cured and trimmed, these were heated in boiling water to soften before bonding to a base board that matches the curvature of the fuselage.

Once waxed, epoxy glass mouldings are taken from the pattern.

[Phil Clark]

First 'all together' motivational shot of the project.......looks a little 'nose too low' here, but considering we still have 9" wheels to add, she'll be a lot more nose up once complete.

[Phil Clark]

After making the foam blank that will form the basis of the canopy hatch pattern, it was discovered the top line of the fuselage was completely wrong (another massive error on the plan!!!). The top line should be a smooth gradual curve from the back of the cowl to the back of the canopy.........as you can see, the fuselage is far too flat producing a kink at the front of the canopy

The upper sheeting was removed along with 3 upper formers & all longerons before reworking to give the desired top line......the amount of drop can be seen by the original profile of the blue foam cockpit hatch blank.

Re-profiled cockpit hatch pattern with balsa slab added that forms the lip that the cockpit glazing is fixed to

[Phil Clark]

More pattern making.......this time, the canopy.

Here's the basic balsa pattern for the canopy. This is 1" oversize on the rear & the base. Once complete, this pattern will have an epoxy mould taken from it which will be used to pour a temp resistant aluminium powder filled PU resin vacform tool.

Next the cockpit hatch & canopy patterns were skinned in 160g twill weave glass. Plenty of work still to go before moulds can be produced.

[Phil Clark]

Going back a few steps, we were not happy with our original forward fuselage louvers. They looked to 'deep' so the pattern was reworked to reduce the depth of each louver.

Here's the 1st set of epoxy glass louvers off the mould with the slots opened up.......MUCH better

[Phil Clark]

First bank of 2 sets of louvers taped in position........