Build thread on the GT-VX2 Explorer.

Resasi

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Joined
Jul 2, 2007
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Location
London/ Kilifi Kenya
Aircraft
Gyrs, RAF 2000/Mgni/Bnsn/Hrnet/Mrlin/Crckt/MT-03/Lyzlle AV18-A/Prdtor. GT-VX1&2, Pax ArrowCopter
Total Flight Time
100+ gyro, 16,000+ other
Gyro Technic Inc now kindly been given its own place in the Builders Forum by Mike and this will be a build thread on the new model that Denis has been receiving a lot of queries about.

His GT-VX1 is a superbly engineered kit that he has developed in over ten years of building and flying his creations. I believe he has built around 11 gyros during this time, each incorporating new ideas and improvements. During his time he also began thinking of producing his own rotors and with Ernie retiring and the present problems with the supply of Dragon Wings it seemed a good time to look into that.

With my own initial foray into the world of gyros with the Hornet and seeing what Denis had produced, I decided that it might be time to try another shot at building a gyro that I might have some input into. I have always felt that I wanted a single seat gyro that would be able to do more than just burn around the local area. Denis had been receiving queries about putting 912 onto the GT-VX1 and this would give more power/ better fuel burn, better performance and some legs to go places, possibly with a bit of camping kit for those fly-in’s that last over a day, or, when you suddenly get grounded away from home by weather.

Gyro Technic does offer build assist and my particular build skills are pretty minimal. I had possibly progressed beyond the hammer and screwdriver abilities I formerly had with our Hornet build but not a lot more, so this was definitely interesting. I contacted Denis and now...suddenly... the build is under way.

Lockwood was where I had initially bought our Rotax 503 for the first build, so, back I went to look at what might be available in terms of a new/second hand power-plant. The GT-VX1 is powered by the 582 and produces a good 2 stroke performance. The 912 is a well established 4 stroke with a good track record and lower fuel burn. It comes as the 912 80 hp or the ULS 100hp. In comparison to the 80 hp version of the Rotax 912 series the 100 hp offers more power while keeping the same weight with a time between overhauls of 2,000 hrs, and, best power to weight ratio in its class.

There are a number of engines out there but with the reputation, proven track record, and widespread familiarity with the product, I felt that I was prepared to put more money into that particular choice. People had indicated interest, and various singles out there are using them. I had contacted Eric Hoskins who builds mustering machines in OZ, looked at the two 912 Merlins in the UK, and contacted Mark who has flown a 912 Dominator in the US. all of whom had indicated their satisfaction with that as a powerplant.

I arrived at Gyro Technic in Kasota yesterday along with the zero timed 912 ULS I had been able to get from Lockwood when I got to Tampa just before Christmas.

Denis has given me the tour, and launched me into the build. Photos are being taken, and hopefully progress will be posted as I go along.
 
YAY ...a 2020 build -thread! Fantastic news Leigh ...today's top choice in the affordable -single class of US gyro! Congratulations So excited for you & see the new creation!
 
First build thread of 2020! Congratulations Leigh!
 
The engine arrived from Lockwood, at the same time as I did in Kasota for the build assist program that is possible with this kit. This was exciting and my Christmas present from Santa looks really nice. I had seen it before Christmas in bits on the bench being zero timed by Kerry in Sebring, and the change is ‘look like new’ amazing.
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Some of the gyro bits have been anodised blue which was the colour I chose, and like the engine arrived the day I did.
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I having admired Denis’s machine which is a real beauty, and hopefully mine may look like some time in the future, was ready to start.

Denis suggested I begin with the vertical tail section and since he has a video on the use of the jig and riveting the tail sections I will include this to show what I started on, a lot more tentatively I hasten to add.


The Vertical section of the tail was done first. The sheet metal has been cut to the required shape and guide holes are in. These placement holes( some) will allow a cleco to be put in, some had to drilled out further.

The sheet is position on the top of the jig. Airfoil shaped machined rib shapes are then placed into positions on the jig. When all are in place the roller bars are then lowered which folds the sheet down on either side of these. These are only lowered part of the way to being, this
allowing the top few rows to be clecoed into position then pop riveted. This can then removed from the jig and finished off on the desk. As you can see it is massively heavy (not), or I am stooping more as I shuffle geriatricly around.

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Then began on the horizontal stab. again begun in the jig before removal to desk and pop riveted towards the trailing edge which is the finished off with a stiffening insert right at the trailing edge and (round) riveted. Slightly different technique and riveting tool.
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These were pretty well finished off, except for trailing edge of the fin as we wait for an opinion from Paul Plack about possible ariel placing.
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I was then able to start watching and helping with the assembly of the rotor blades.
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This is the leading edge of the 12’ rotor blade. I am estimating that I will be using the 25’ set, the hub bars are a constant 1’ and weigh 11.55lbs. The single 12’ blade weighs 21.472lbs, complete set of 25’s will be 54.494lbs.

Denis has a set of DW 24’s and Sport Copter 24’s and so a comparison of weights with his 24’s was.
DW’s 45.7lbs Sport Copter’s 53.2lbs Razor Blades 52.862lbs

The blade making process was very interesting with the component parts, leading edge, upper and lower skins, both end plates, tip weight root bolting insert, and bonding test strip for adhesion testing after curing, being placed into an etching bath. As the leading edge required slightly longer etching time the skins and other items were removed and placed into the first rinsing bath first where the surface deposit is cleaned off, and then into a second rinsing bath final cleaning before being dried.

When dry the adhesive which is in a tape form sandwiched between two covers is then laid out into position with covers removed, blades assembled, and then placed into the autoclave. There the blade is then clamped to specific trailing and leading edge pressures and then baked to a specific heating and cooling cycle. Each blade's components come from specific batches, all of which are recorded along with the curing graph details, and adhesive test strip which go with each set of blades which are cured as a set of two blades.

The next step will probably be to start assembling the tyres, and the instrument pod.

Presently getting ready for the snow storm heading our way. Luckily the workshop is pleasantly warm as I do not do cold very well. If we do get snowed in no worries as supplies are in and a long way to go.
 
Thank you for sharing the fun Leigh.

I great story told well.

It looks like kinetic art to me.

I am not a two stroke enthusiast so in my opinion the Rotax 9 series engine is such a good choice.

Are you going to keep her here or take her back to England when she is finished?
 
And I like a nice turn of phrase Vance, and kinetic art is a great one. I rather fancy myself as an artist in metal, the reality however, something different. This is the vision that Denis has conjured up, and I merely making a reproduction.

The difference between this and our first build is huge. There we were stumbling in the dark and working from plans. Ordering the material cutting, grinding, bolting... often ruining. The plans here are amazing 2 and 3D, all the required parts immediately to hand. With the build assist, the jigs are right here, correct tools, and an experienced eye to oversee, guidance when needed.

I am not a natural builder and our first build an often frustrating and wasteful process. This is hugely different. A huge spacious comfortable work shop that is a pleasure to work in Denis and his guys Grant, Mike snr, and Mike Jnr, all friendly, helpful and great company and learning new skills. This is really instructive in a very positive and reassuring way.

The jump to the Rotax 912 from the 503 or 582 was always an aim for the extra power with fuel economy. A good reputation with lots of them out there, extra power for those odd occasions where things may have got a little bit wrong, bit hotter, field was a bit shorter, the trees a bit higher.

Hopefully eventually the UK, Vance.

The voyage back there however will be a slightly complicated one. We have to complete this one as a new model, get it certified here. The 40 hrs flown off to establish the limitations, and complete Phase 1 flight testing and a POH completed.

Get the new plans done for this model in 2 and 3D, see that UK CAA Section T requirements are all met. An application will then be made to the LAA in UK for consideration as an amateur build there. This includes submission of the plans and proof of compliance with Section T.

If approved, the kit then brought over for assembly under the supervision of an LAA designated inspector, test flown by the CAA/LAA test pilot, and, if it passes, issued a permit/airworthiness certificate. That at least the gist of what lies ahead.

Anyway back to work, just finished the instrument pod, couple more end plate parts to finish before starting on the vertical fin.

Have also done work on two rotor blades.

P.S. the snow storm has arrived. Looking pretty chilly outside.
 
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Been really stuck into the rudder, horizontal stabs, instrument pod, and vertical fin. The sheets went onto the jig clecoed in part riveted removed and finished. In line with FAA 51% requirements guide holes have to be drilled for clecos, then quite often again for the rivets.

Two kinds of rivets, pop and round headed. Different tools for both and all new to me, but great fun.

Leading edge vertical fin. Out of the jig
20200117_200148.jpg
... now lots of clecoing and riveting

The blade making has also been new and interesting, etching rubbing off on the two rinses, drying laying out and applying the adhesive, making up the blade attaching the tips, tip weights, hub bar mounting base to leading edge spar. Laying out adhesive for top and bottom skin, baking then removing.
20200115_143516.jpeg


Did some milling of the top and bottom plates for the vert fin
20200117_190737.jpg

Finished the horizontal stabs last night, and began vert fin. Into the jig and repeated the process done for the rudder. Think I may have now finished this section.
20200118_101350.jpg


Lots more photos...and building to do.
 
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Getting some popcorn. I'm going to sit back and enjoy this. Keep the photos coming Leigh and enjoy yourself and the experience.
The experience has been amazing, all the people here have been so kind and friendly. Denis has a great workshop where he does some pretty advanced manufacturing, his attention to detail and standards is inspiring. A build assist really is the way to go with Gyro Technic.

The machine I am now making is so far removed from that first build that it fully explains Stuarts comment when he had visited Gyro Technic.
“ Dad...it made our machine look positively dangerous!!'

The build quality that I am able to achieve here, is way ahead of what I could do in the garage at home. I am really enjoying this, and the confidence it inspires in this being a structurally safe machine is hugely reassuring.
 
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More work/progress yesterday as most of the sheet metal riveting has been done I started on the rudder pedals. A gyro buddy of Denis’s, and a Forum member Gyro Paul came down from Minniapolis to spend some time, it was great to meet him. Always nice to meet other Gyronaughts, from around the country. He very kindly was helping me with taking photos to document the build, and then helping me hunt for the right bits as the jigaw puzzle comes together.

The documentation, plans, and packaging of the parts is absolutely first class and saves so much time. The attention to detail is extremely helpful.


Highlighting the parts.
20200118_094236.jpg
I blew this one up to show the difference between leaving the piece as is, or just shaving an edge to highlight it. Denis has done it on his Black Gyro and it really does make it stand out. I wanted the same for the Blue.

So shaving an edge. Did this with a lot of parts
20200118_124710.jpg



Next on to the rudder pedals
20200118_131523.jpg

Next riveting with the big round head rivets
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Next on the assembly frame laid the front section of the keel beam.
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Next the drop part of the keel, and then last tail beam
20200118_162704.jpg


Deburring and drilling out the holes.
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The attachment point for the undercarriage strut goes on.
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On with the seat bracket, note the concentration, its very tricky tightening bolts...or I've just realised that I forgot to put the washer on!!!
20200118_165247.jpg

Steps back to admire.
20200118_165412.jpg
 
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Since only allowed ten pictures, will carry on with the tale here.

Pictures were demanded popcorn ordered so mustn’t disappoint any prospective audience.

Pressing in an insert to the nose-wheel housing
20200118_170758.jpg

Done
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Most important. Not allowed to fly without the official company logo
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Attention now goes to the nose-wheel assembly
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Will it steer??? ....Not without pedals
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Nose-wheel centering springs have to go in this sucker and it
is a bit of a squeeze.
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Bit of a struggle, helps to have strong thumbs.
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Cap on, then onto a developing airframe.
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Starting on the mains now. Struts attached to keel.
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Pretty sure something will go here.
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Well it seems the limit has been reached... however...
 
...on with the build. Time is pressing.

A front strut would seem to be a good idea.
20200118_192353.jpg



...and about steering. Pedals go on.
20200119_143954.jpg




Thought we might try moving higher up so the upper mast plates go on.
20200119_145607.jpg

Need an instrument pod so in go some pod supports
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Some of the mast folding structure
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And on it goes.
20200119_164247.jpg


Tall tail support rods...and yes on tiptoes to get those on.
20200119_170825.jpg


Well another long day. Definite progress being made, the table full of parts is clearing. The tail pieces and instrument pod will now be taken to be powder coated our lovely blue which, with the silver rods, golden bolts, and the highlighting accenting of the shaved edges of various parts I think is making for a very fetching colour scheme. Lots more to do with mounting the engine... and... and... and.

Still thinking of a name. When we were building ours Stuart wanted ‘Dudu’ for its name. A Swahili word they use for insects/Hornets, so I agreed. At some stage at a Bensen Days someone came up with a slightly puzzled look and asked me why I had called it that, so I told him, and he wandered off. Little while later I passed a friend and asked him what dudu was in American.
"Piece of sh*t." came the reply!

I am giving the name for this one a bit more thought this time.
 
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Hi JM, thanks for visiting. Your tail looks lovely. I will weigh mine when it is all together.


Fortunately when all done it did straighten and become smoother. I must confess my riveting is not yet up to any sort of standard.
20200120_095612.jpg


Fortunately when completed the wavy tail did improve.


The top...
20200120_095639.jpg


...and bottom. Not looking so wavy now.
20200120_101220.jpg

Yes JM it is a two piece with the Vertical fin and a nice large rudder with a lot of authority, which I like, because I would imagine that going from a 582 to the 912ULS 100hp I may well need it

I am unfortunately definitely in the builder category of ‘dangerous with a screwdriver and hammer’. I never really imagined building a flying machine and only did so because that seemed the only way then, and because it looked a fun project to do with my son...and it most certainly was.

In fact he credits the fact that, because he built the gyro and got his repairman certificate, he was able to get his first job offer with Allegient Airlines. He never took the job with them as soon after he was offered a job with Delta Airlines as a Tech 2 in line maintenance at LA. He is very happy with them though LA was pretty far to commute to see the kids in Tampa. Fortunately managed to move to Detroit, which cut down on time spent flying and is at least in the same time zone. He just told me yesterday that he has now got a move to Atlanta approved which is closer still...and warmer.

I did enjoy our project, but was aware that it was a rough job, I loved the way our Hornet flew and sad when we had to part it out when funds ran low.

Things improved and I have always been impressed with Denis’s work, so when this opportunity arose have been delighted to be able to come and do this build assist program here in his shop.

It is still pretty cold here but the workshop is warm and a great place to work. Speaking of which, things to do...
 
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JM I have found that feedback on the Forum is nearly always helpful and informative. I also like the idea that with other sets of eyes boo-boos can be caught and rectified before they are taken into the air and found out the hard way.

With regard to the tail, it is two piece.

20200120_122748.jpg
Denis has mentioned to me the power and authority his tail design has which I find reassuring, particularly when moving to the bigger engine.
 
With the upgrading of the power-plant, ability to carry more fuel and possibly some additional kit into grass and rougher fields, I had thought about getting larger tires.

20200120_122445.jpg


20200120_122458.jpg

Nose wheel

But when I arrived here and saw the tires Denis has, I think that these will be fine. He flies with them great on the 582 and, speaking for the gyro of course... I am not considering going any fatter.20200120_122533.jpg
 
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Trim referring to the pitch attitude and airspeed condition established by an offset gimbal trim spring arrangement on the rotor system we generally use. By adjusting trim spring tension we can change/establish a trimmed airspeed of the gyro. People fit various ways of altering this spring tension. For some ground, adjustable only. Scot Essex did a very nice kit which I used on the Hornet which could be changed in flight. Ideally a pitch stable gyro should self-restore to the trimmed pitch attitude and airspeed situation it was in before any gust updraft or pilot input that disturbed it.
 
Few more additions today, began by going down with Denis to get the tail, and pod powder coated to match...as closely as possible the frame.

Uncrated the engine then slung it above the mocked up frame to begin working on the engine mount alterations required for the heavier more powerful engine. About 80lbs heavier and 35hp more than the 582 on the GT-VX1.

20200120_172422 copy.jpg

And into position.

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The engine looks lovely, Lockwood did a nice job.

The seat went on.
20200120_172110 copy.jpg

A racing bucket seat it is very light strong and wraps round. I have sat in Denis’s and it is extremely comfortable with a good 4 point harness and a push in and click buckle rather that a lift flap which a friend of mine has and it always inadvertently opening.

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Pretty securely fastened to the frame.


The parts table is slowly beginning to thin out.

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Been looking at radios and considering propellors. Am thinking about the MGL V16 which seems to have good reviews, I cannot say the same for the V6 which Mark and Dennis have been having lots of problems with. The V16 I has good reviews on the VANs Forum, with a Vega head, and an MGL Xtreme mini EFIS.

I did try to contact Paul Plack about the arial placement on Denis’s machine and which I may try and copy unfortunately no reply to date.

It looks a good location but with very minimal knowledge on arial placement I just don’t know. Denis has made an alteration that will allow the wiring to be routed through the tail to the arial as opposed to outside as is shown below.

20200116_171312.jpg


With regard to propellor. With the 912ULS we have a slight problem with blade length constrained by keel and tail support tubes overhead. 62“ and a lot of power to soak up.

Powerfin could only do it with 5 blades but spoke with Daryl at Warp Drive and they can do it with only 4 blades. Whirlwind props had nothing Bolly nothing. I do like the strength of the Warp and liked my old 3 blade 62” which gave a best static thrust of 319lbs on a 503 DC DI.

Since this is intended to go into slightly rougher strips the strength of the blade, and one less, is a big consideration with regard to stone damage.
 
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