GT400 Construction Page
Construction from the Boxes to the Test Flight
The following is a chronicle of me building a Quicksilver GT400 with the list of extras. After looking at updates available we have come up with a nice little package to enhance the GT400. Having built a couple of Quicksilver GT500’s and a Sport 2S this was new territory for me, having owned a GT400 in my early years of flying (which I bought assembled). So although it is a scaled down Quicksilver GT500 there are similarities but many differences, so I have decided to put these pages together so you can see how easy it is to build and fly your own Quicksilver ultralight. Quicksilver kits are ideal for the “average joe” to build their own aircraft. You do not need an engineering degree to put a Quicksilver kit together, the assembly manual is easy to follow, and very straight forward. All but a few parts are pre-drilled and ready to assemble. It is not unlike the old “Meccano set”. Some sections are already pre-assembled. When you are finished you will have the satisfaction of building your own aircraft, and more importantly you will know every last nut and bolt that keeps you in the air. The aircraft can also be supplies as a factory built. Once assembled, you would, of course, get it checked out by an aircraft inspector before getting it registered.
The popular accessories to enhance the Quicksilver GT400 are:
Disc Brakes (Black Max), 6” Alloy Wheels, 6” Alloy Nose Wheel (from the GT500), Tundra Tyres (18”), GT500 Windscreen, In-Wing Tank, 2 piece GT500 Nose-cone, Wider Yoke, Updated Instrument Panel, Electric Start, C Box upgrade, Oil Injection and extra wing ribs.
(All of these upgrades will be on this Quicksilver GT400 we are building)
THE JOURNEY BEGINS
We started with the shipment arriving from Sydney after spending a few weeks on the ocean from LA.
In theory these 4 boxes and a tube (plus some basic tools) could be dropped into the middle of Australia, and around 120 man (or woman) hours later, after adding some oil and fuel, you would have a fly-away aircraft.
This is the boxes all un-packed ready to start the assembly process
The assembly manual is well set out with exploded views of all the parts, with a description of what parts go in what order, guiding you through the assembly process. Most parts are pre-drilled. For most for the assembly the tools you will most use is a 3/8 and a 7/16 socket and spanner.
STAGE 2
STAGE 5
STAGE 4
STAGE 1
STAGE 3
Assembly of the forward tube, axles, brake and wheel assembly.
(this has the optional Black Max brake system and optional tundra tyres)
Assembly of the root tube, aileron control and cabin frame.
Assembly of the rear tube, rudder, elevators and all associated hardware. This is probably one of the hardest bits of the assembly as the Dacron has very tight tolerances (but it does fit), so it requires careful reading of the instructions and most importantly patience. This stage and the flaps and ailerons are probably the most challenging.
Attachment of the rear tube to the main body, and align, measure and check it is square to the front tube, also attach and adjust elevator controls. Also attachment of the fuel tank and straps, and the flap handle controls, which will be on the main tube (like the GT500) instead of the root tube, due to the option of the GT500 wing fuel tank in the middle.
Assembly of the seat and seat track, control wheel, extra fuel tank bracket, front wheel assembly and rudder pedals.(this has the optional Quicksilver GT500 front wheel assembly)
The ailerons and flaps are just as difficult as the tail end, with very tight tolerances, but they do fit. I found by spraying some INOX lanolin spray liberally on the tubes before pulling the covers on, will make for an easier fit. Also making sure the tops of the rivets holding the cross pieces are smoothed with a fine file will help as well.You need to bunch up the fabric and pull down to get the top in place first, then pull down and smooth out the snag points, before slowly and carefully doing up the zips. The spray dries out in a few days.
STAGE 6
The internal wing structure was assembled, then dis-assembled and slid into the wing skin, then the skin was stretched to the right shape on the wooden rack. Wing battens were slipped into place, and aileron and flap eyebolts were attached. Internal bits were then attached to LE and TE spars. The second wing will take half the time.
I just got the front pod and the backplate back from the paint shop.
Mal from M J’s Motorcycle Repairs did a great job with a 2 pack clear finish over red. He did a good match of the paint colour to the sails as well. This is going to look great.
The starboard wing is finished and the flap handle and connecting rod installed. The pod and backplate has been fitted, and will be working on the GT500 style windscreen next. Once again a bit of customising will be required. Finishing off the engine install after that.
Engine all installed, pretty straight forward Rotax 503.
STAGE 8
Fitting the GT500 style windscreen was a real pain, as the side rods had to be shorted to fit the shorter aircraft (which was not as simple as it sounds). Patience prevailed, it was time consuming but finally got it right. Looking good. Also the fitting for the removable nose cone went on. The instrument panel was also fitted to the pod, after cutting an extra hole to accommodate the compass. All ready for the instruments now and the wiring. What has been taking the longest bit with this kit is the customising and grafting of GT500 bits. The patience doing the extras is worth it, as the extra bits really do enhance an already good aircraft.
Fitting the rear pilot enclosure is a very tight fitting, so cord had to be attached to the holes for the rivets in the aluminium strip on the front edge to get it tensioned and placed right. This was a two man job, and patience is required to get the creases out as you go and get front edge in the right place. It is also an easier job with a pneumatic riveter.
The instrument panel is in and ready for the instruments to go in and to be wired up.
I finally got back into the finishing off the Quicksilver GT400 after being tied up with another project. The instrument panel is all finished and ready to be installed. I have had to re-think the wiring for this one, as the basic GT400 had only a limited wiring loom, and normally only has an ASI, a tacho and a CHT and a pull start. I have had to virtually copy the GT500 loom.
By adding the VSI, EGT’s, Altimeter, compass, circuit breakers, Hobbs Meter, electric start, battery etc, the aim is to basically have a single seat GT500 with all the GT500 inclusions (You can never have too many instruments). This instrument panel is basically from the GT500-582, so I have had to work out an extra loom to handle all the extra bits.
So far I have taken around 65 hours to get to this stage.
FINAL ASSEMBLY:
Finally got to the “final assembly” stage. With the wind and the rain the way it has been, it has been a struggle to get any work done (whatever happened to those nice winter days, global warming?). The “customising” has also been time consuming but it will all be worth it in the end.
Had a few issues with the customising of the GT500 windscreen and top screen, as the GT400 is shorter than GT500. I had to work it all out without mucking it up. It’s the old story “measure twice, cut once”.
Still have a bit of tidying up of the wing battens, as this unit has the extras to be installed. Also need to sort out the GT500 flap controls (more customising).
Everything is pretty well in place, but now the big job of starting from one end and going right through and checking every bolt is done up, every pin is in place and everything is where it should be. The next step after that is to adjust the wing washout, rudder deflection, rudder and aileron angle, and of course the weight and balance.
I would like to think that weather permitting that we should have the engine run in and be in the air sometime this week.
Well, we finally got closer to the stage of getting the Quicksilver GT400 in to the air. We did the weight and balance and everything was within tolerance of the assembly manual. I was a bit worried that the nose was a bit heavier than the GT500-912 (that I have been flying regularly for the last 12 months), but the early testing hops proved all to be OK. Wing washout, aileron and flaps adjustment done.
We spent a full day checking that all the nuts, bolts and pins were in place, with 2 people going over a second and a third time, we still found things to do before taking the final step of getting the Quicksilver GT400 in the air. When you get to this stage of the assembly you realise that this is the most important part of the whole equation, as your bum is going to be in this seat when you’re climbing out at 1400 ft a minute, so it has to be done right.
After spending the 77 minutes to run in the Rotax 503 it was time to put all the hard work to the test. A series of hops up and down the airstrip proved that the balance was right and all of the controls were working correctly and responding as they should. (see the video)
Back to the hangar for a further check that everything was all OK after the hops shakedown.
A few extra stand-off ties and a last minute power problem with the radio to solve and we were ready to go. The time had come to see the fruits of all the hard work and TLC.
Having flown the GT500 and the Sport 2S for the last 8 years, and not having flown a GT400 since my early days, it was a pleasure to get the aircraft in the air and realise again what a fun machine the GT400 is to fly. Responsive, safe, nimble and easy to fly is the best way to describe the GT400.
All the customising has been well worth it, and made vast improvements on the original.
Thank you to all who have been following the construction of the Quicksilver GT400, as you can see it is not as hard as it looks. I will get some “in the air” footage over the next week or so to add to the website.
What will be my next project ??? Mmmm
THE BIG FINALE
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This construction page is purely instructional, and any ultralight aircraft that you build should be registered, checked and test flown by the appropriate authorities before flying the aircraft yourself, and you should have the appropriate licence to fly ultralights.
Ultralight aircraft flying can be dangerous, but only as dangerous as you make it. Pre-flight checking of your aircraft before takeoff, not flying in bad weather and using your common sense to the max, will have you flying safely for many years.
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STAGE 7
This page is dedicated to the construction of the GT400, but the principles are the same for the GT500 and Sport 2S and MX series.
STAGE 9
STAGE 10
Everything is pretty well in place, but now the big job of starting from one end and going right through and checking every bolt is done up, every pin is in place and everything is where it should be. The next step after that is to adjust the wing washout, rudder deflection, rudder and aileron angle, and of course the weight and balance.
I would like to think that weather permitting that we should have the engine run in and be in the air sometime this week.
(A few days later)