Build thread on the GT-VX2 Explorer.

[Resasi]

I have been getting feed back from members following the build, which as I have said before, is a very welcome ‘eyes on’ from people who have either, have had experience with, or see possible problems with certain aspects of the build.

Ron expressed his views on the EFIS, and while I did not agree with that, have also now received further reservations and information that has given me pause for thought, and perhaps will need some further investigation.

Helipaddy a long established member of the Forum, who with a two seat ELA and a single seat Dominator in addition to being a professional helicopter pilot, is certainly be someone who one would benefit from listening to, has drawn my attention to a very recent LAA technical information leaflet concerning the growing use of EFIS in light sport aircraft, their suitability, limitations, and acceptance by the LAA for their approval in 51% build aircraft. Also to possible reservations about the effects of rotor shake, which is peculiar to gyros, on some components In the LAA TIL I also see that although certain MGL products are mentioned, the intended EFIS is not.

This certainly deserves my thanks to Helipaddy, and further investigation and follow up, which will be done.

Just before this, Denis had at my request done a possible upgrade to the build, which looked very good, (I really liked the look of it.) but will now be on hold while I do some further checking.



It may just be that this ‘all glass’ panel I was looking for may possibly have to be re-thought to accommodate some older but more established back-up instruments.

 

[Hueychief]

Leigh,
I would highly suggest looking into an ADS-B 2020 compliant Transponder for your safety as well as others around that may be situationally unaware. Cost should no longer be a limiting factor, but panel space may be the challenge for most. I understand why a hang glider, paraglider and possibly even a trike may not feel the need for one, but I've had my share of near misses almost running someone over because they weren't where they thought they were. My personal gyrocopter will have a TrigTT22 ADS-B Out bundle as shown here with a Stratux ADS-B In. Super handy for situational awareness along with Metar/Taf, weather, etc......

 

[Resasi]

Jeff got it covered. Planning on ADSB in and out. Bundle presently being looked at:-
STX 165R Sandia Aerospace Remote Mode-C Transponder
H-Coax-Sandia-8 RG 400 coax cable for V16/Sandia/EchoUAT, BNC & 1 SMA
ANT-DPA-TRNS... Transponder Antenna - Delta Pop - Airfoiled
H-STX 165R HARNESS - for Sandia STX 165R Harness
EchoUAT uAvionix EchoUAT ADS-B Transceiver
H-Coax-Sandia-8 RG 400 coax cable for V16/Sandia/EchoUAT, 1 BNC & 1 SMA
SkyFYX EXT uAvionix SkyFYX 2020 Compliant GPS External Mount

Good news, fuel tanks arrived, exhaust system on the way. Battery arrived, overflow bottle ordered will be sent when they get to Lockwood, alternative flatter Carb filters on the way..., hopefully pictures will once more be...on the way.

Sounding a bit like ‘two weeks’ ???

 

[Resasi]

Well the new tanks arrived and now trying them on. Bigger than the others, the first cone shaped air filters would not fit. So ordered the flat round ones which I think may be OK. Had ordered from Lockwood but haven’t arrived yet so checking on that.

The radiator showed up and looks good.

The initial Rotax exhaust I had ordered was unfortunately going to put more weight below where it was not wanted and the pipes weren’t compatible with placing it above so a different exhaust set up was ordered but due weather won’t arrive before at least Monday. So with waiting for exhaust, and air filers and overflow bottle to arrive, new engine bearers to be made fitted checked then anodised, a pause is now on

One of the fuel tanks was filled with water yesterday to weigh and confirm the volume…. 4.8 Gallons.. So…. 9.6 Gal total. A little shy of the 10 Gallon target I had aimed for, but that should still give a range quite a bit in excess of the 45-50mins I have been used to along with the power to carry the weight of a bit of kit, more robust gear, and heavier pilots with hopefully a more sprightly performance and high altitude performance for those that might need it.

They do look a bit like scuba tanks.


They, and the gyro are however a very much higher quality build than the Hornet my son Stuart and I initially did. With the 503 when I did the first Phase one test with full tanks at Zephyrhills it was a summer day. Nice long runway and got airborne with no trouble, accelerated nicely down the runway, having decide it was a go, the climb out then proved interesting, as did the subsequent circuit...and... 10galls was declared over the limit for those conditions.

I did think she was was a thing of simple beauty though.




And handled very nicely. Wasn’t entirely happy with the tail though.

 

[Resasi]

I have an apology to make to Paul Plack. I had addressed a question re Denis’s arial placement and Paul had very kindly replied, and which I had intended to share, but hadn’t. Thought I had posted it last nigh but do not see it today so another try.

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.

Reply from Paul was:-

"I apologize for the sluggish response. I'm just back from two weeks at my sister's place in rural Kansas, where my access to internet was very limited.

I have used modelling software to predict the performance of antennas mounted on open-frame gyros, and in my experience getting the gyro modeled accurately is very difficult. Denis's scheme, with a half-wave dipole mounted off the trailing edge of the tail, looks like a novel approach and would seem to solve some common issues. I would have a couple concerns which could be checked out on Denis's machine:

(1) Make sure the installation is checked for VSWR using a proper antenna analyzer connected to the end of the coax which normally plugs into the radio. This should be checked across the full range of rudder defection in both directions. The V16 has a crude VSWR readout function when transmitting, but the manual disclaims its accuracy. The radio will protect itself against antenna faults by cutting power automatically, but you don't want that to actually happen if you can prevent it.

(2) If you have the means, check the antenna's polar response pattern to identify any dead spots in its coverage caused by interaction with the airframe. I'd expect at least a partial null in coverage straight ahead due to blockage from the airframe and pilot, but it may be surprisingly minimal. This effect may also vary with rudder position. The easiest test I could picture would be to park the aircraft on a compass rose, tune in a weak, distant AWOS/ASOS station, and park the machine at varying angles to the signal's heading. If the signal drops below the squelch level in some directions, the same level of degradation will happen on transmit.

(3) I'd be a little concerned that good quality coax might not be happy bending every time the rudder deflects, but if it's routed with this in mind, it may be fine.

(4) Any loose rivets or other hardware on the tail may manifest as "static" during transmit or receive when in flight. This includes rudder cables. Keep things tight and in good contact or, if you can't, intentionally insulate them from each other.

Denis's experience with this antenna will trump any of my concerns. Give us a report when you get up in the air and try it, and good luck! Your build thread is great!

Paul"

Denis wasn’t happy with his cable routing and had incorporated a rather nifty flare in the rudder trailing edge midway down that will allow the co-ax to bet fed through the rudder all the way to the exit spot at the trailing edge, rather than coming out and along the side as it does now.

As to loose rivets or hardware, all riveting was inspected closely by Denis. I am mortified to admit that I had two that were required to be drilled out and done again, the rest I can testify were snug and tight. Can’t think of any other loose hardware in that area.

 

[Resasi]

More snow last night, nippy outside. Winter would certainly seem a very appropriate time for building inside and catching up on theory.


The new exhausts now mounted look great. (Note the lugs in the prop hub to mount the Warp drive blades.)

Denis did however have reservations which are very pertinent. The pipes do extend quite far back. If a prop blade were to stop directly behind one there might be a possibility of heat damage.

Grant is going to contact and see if the factory can get a slightly different pipe config that moves the main body forward so rear pipe does not get so close to the prop.



Outlet points down...might point up? Sound concerns? There is an additional/optional silencer adaptation with this system.




Warp blades being mounted.


The plate is probably not as sexy as a prop spinner, but the 4 blades and that hub plate does look rather purposeful.

In the above picture, if you look down the trailing edge of the rudder from the bottom silver stripe on the GT logo you will see the flared exit for the co-ax cable for the rudder mounted arial we will be trying for the radio.

Blue just looks better and better every step of the way, I am very excited about this machine. It is a dream coming true and the ‘Explorer’ closer to that affordable but rugged single that can take one places.

This shot also shows a better view of what looks like the collective along the left side of the seat, but is actually the prerotator actuator. By raising this lever, when the safety latch system, shown earlier in the thread, is released, the prerotator is engaged. I am not going for the twist throttle that can be incorporated into that, but for a conventional throttle quadrant which will be mounted just above the handle, and inter-operable with the left hand.

Just looking at Blue compared with the original Hornet one can see the huge difference, and get some idea of the massive amount of thought and development that Denis has put into to GT-VX1 and now 2.

This is now evolving into a serious rugged bare bones x-country single seat machine, compared to the light 'round the patch’, fun machine the Hornet was.

 

[wolfy]

If you are considering a different exhaust maybe you could look at a 4 into 1 system, these engines (like a vw) respond well with a 4 into 1.
And in fact don't make there rated power without one.

wolfy

 

[Jazzenjohn]

Would you have more prop clearance if the exhausts were swapped back to front on opposite sides? It looks like a tighter bend on the one side.

 

[helipaddy]

switch the headers around, front to rear.

 

[Resasi]

If you are considering a different exhaust maybe you could look at a 4 into 1 system, these engines (like a vw) respond well with a 4 into 1.
And in fact don't make there rated power without one.

wolfy

We were not concerned with more power, just simplicity and geometry of the system.

Did you make a custom fuel tank outlet at the bottom of them ? as they are upright it seems probable
if it is the case how did you make this custom outlet, did you solder a threaded aluminium part or is there a simpler method to do it ?

Ordered them from the manufacturer to our spec.

switch the headers around, front to rear.

Unfortunately both took us too far. On the front, impinged on the area where the oil reservoir is going to be positioned, on the rear too close to the prop even when swopped. The supplier seems willing to work with us and supply the fitting that we want to keep the can centred.

 

[wolfy]

We were not concerned with more power, just simplicity and geometry of the system.

Understood mate and agreed regarding simplicity.

wolfy

 

[Vance]

In my opinion pointing the exhaust up will make things seem quieter from the ground Leigh.

It is my observation that sound is surprisingly directional.

 

[Capt'n Gator]

Looking really nice, any speculation on a sale price? I want mine in an anodized Red

 

[Resasi]

Looking really nice, any speculation on a sale price? I want mine in an anodized Red

I think you get a quote from Denis, it does vary according to exactly what one wants. Red would look good, his brakes are that colour and look very nice.

In my opinion pointing the exhaust up will make things seem quieter from the ground Leigh.

It is my observation that sound is surprisingly directional.

I would rend to agree with you Vance, and in these present times there do seem to be more and more noise sensitive areas.

 

[GyroRon]

I think I ruffled feathers when I posted earlier that I didn't like the idea of the Efis panel.... So I am reluctant to post my thoughts on the exhaust.... But I am GYRO RON afterall, and GYRO RON has always had a problem with keeping his opinions to himself! LOL

I do NOT like the exhaust you guys have chosen. I am a big fan of a 4 into 1 system and also a fan of something quiet. Those 912 engines can be very quiet with a proper exhaust.

Why not install something like this?

http://www.falconaircraft.cz/en/inzerce/inzerat/zenair-ch-601-and-ch-701-exhaust-system-rotax-912

1150228 Pipistrel Alpha Trainer Rotax GmbH 912 UL2 Standard Exhaust System GEN2 | eBay

Find great deals for 1150228 Pipistrel Alpha Trainer Rotax GmbH 912 UL2 Standard Exhaust System GEN2. Shop with confidence on eBay!

www.ebay.com

Or if you feel like it can't be under the engine, something like this,

CKT Stainless Exhaust, Overhead, Rotax 912/912S (7820-013)

CKT Stainless Exhaust, Overhead, Rotax 912/912S (7820-013)

www.seareyspecialist.com

I will admit, some of the exhaust systems are damn expensive

 

[Sv.grainne]

I was looking through your posts and photos and did not see a picture of the flight controls. Specifically looking for an image or two of the pivot block setup and control forks for rotor head control. Do you have any yet that you can post?

 

[Resasi]

I think I ruffled feathers when I posted earlier that I didn't like the idea of the Efis panel.... So I am reluctant to post my thoughts on the exhaust.... But I am GYRO RON afterall, and GYRO RON has always had a problem with keeping his opinions to himself! LOL

I do NOT like the exhaust you guys have chosen. I am a big fan of a 4 into 1 system and also a fan of something quiet. Those 912 engines can be very quiet with a proper exhaust.

Why not install something like this?

http://www.falconaircraft.cz/en/inzerce/inzerat/zenair-ch-601-and-ch-701-exhaust-system-rotax-912

1150228 Pipistrel Alpha Trainer Rotax GmbH 912 UL2 Standard Exhaust System GEN2 | eBay

Find great deals for 1150228 Pipistrel Alpha Trainer Rotax GmbH 912 UL2 Standard Exhaust System GEN2. Shop with confidence on eBay!

www.ebay.com

Or if you feel like it can't be under the engine, something like this,

CKT Stainless Exhaust, Overhead, Rotax 912/912S (7820-013)

CKT Stainless Exhaust, Overhead, Rotax 912/912S (7820-013)

www.seareyspecialist.com

I will admit, some of the exhaust systems are damn expensive

No feathers ruffled Ron. I did want a 4 into one, and had it. Unfortunately could not fit it under, or over, due the geometry of pipes and where various other bits were positioned.

These can be fitted with silencers if too loud.

I was looking through your posts and photos and did not see a picture of the flight controls. Specifically looking for a image of two of the pivot block setup and forks for rotor head control. Do you have any yet that you can post?

 

[PW_Plack]

In my opinion pointing the exhaust up will make things seem quieter from the ground Leigh.

Also, possibly louder inside the helmet, and with an odd modulation from reflections off the rotor. It will also require some measure to prevent water collection.

 

[Sv.grainne]

No feathers ruffled Ron. I did want a 4 into one, and had it. Unfortunately could not fit it under, or over, due the geometry of pipes and where various other bits were positioned.

These can be fitted with silencers if too loud.




View attachment 1146614

No feathers ruffled Ron. I did want a 4 into one, and had it. Unfortunately could not fit it under, or over, due the geometry of pipes and where various other bits were positioned.

These can be fitted with silencers if too loud.




View attachment 1146614

Thanks for the picture, nice.

Bobby

 

[Resasi]

Also, possibly louder inside the helmet, and with an odd modulation from reflections off the rotor. It will also require some measure to prevent water collection.

Both good points Paul. As always having many eyes on can certainly bring considerations to light, that flew right over my head.




Presently 'doing a swan’.

Serene above with little showing, legs going like buggaree under the water.

Headway is being made.