RE: Skygate Hawk - build (virtual manual)
 

Mark should be although I am also looking at a servo option as well mounted on the front of the nose gear formers so access is easier, this could be linked through Rx to sequence with gear etc.

marcs

RE: Skygate Hawk - build (virtual manual)
 

After fitting the hinges I squared up the cut-out in the fuselage, then sanded the doors (still in one piece) to give a nice even gap all round, once happy I taped the doors to the fuselage opening in the correct position. Inside I moved the hinges to rest on the gear doors and marked them with a marker.
In the past I have used a small Proxxon milling machine to cut slots in composite control surfaces with good results so used the same method to make the four slots required to glue in the hinges.
Once the slots were cut I removed the small door from the end and cut the door panel into halves, then taped back together with an even close line.

RE: Skygate Hawk - build (virtual manual)
 

Next i turned my attention to the operation of the small rearward nose gear door. This is not a full scale build so for the sake of reliability and simplicity I was looking for an alternative method for running this door. Options were:

- Linkage connected to nose leg
- Servo driven via a linkage
- Air cylinder driven

Spent a few hours doodling various ideas and decided to try a set-up using an air cylinder, this was the 'cleanest' option as I could just hook it into the main gear door air feeds.

I had a BVM air cylinder (2") which looked about right, next had to try to get it at the right angle to drive the door. I came up with a mount (FR4 board) which I attached to a small piece of 'L' aluminium via two bolts, it was secured to the main gear former by 3 x M2, and positioned so the cylinder was clear of the nose wheel and overhung the nose gear door opening. I cut the mounting holes in the FR4 plate into 10mm slots so the whole plate could be moved up and down to allow fine tuning of closure.

I slotted the small door to accept a small strip of glass board which I plan to attach the air cylinder to.

Still work in progress but it just might work, and if it does it should be reliable and easy to maintain.

marcs

RE: Skygate Hawk - build (virtual manual)
 

Mounted the small door using the brass hinges, took a little fettling as the small door varied in thickness from edge to edge so the door would not sit flush with the fuselage bottom, a little work on the mill recesses the hinges to take into account this variance.
Taped one door in place ensuring correct gaps all round, filled the two slots cut for the hinges in the door with some 20 minute epoxy and pushed the two hinges into place - will leave to set and then repeat for door two.

Started to paint the front nose leg former assembly with grey primer as it will be difficult to get to it once in, making sure to leave exposed wood around the glueing surface to create the best bond.

Been debating cutting a top hatch in the fuselage, comments from some owners suggest there should be one to make access to turbine and other components easier etc, the top of the fuselage has two possible options, one hatch just behind the cockpit and running to about half way along the spine, the second from there back to fin, my preference is the first hatch.

QUESTION:

The servos driving the elevator are positioned a few inches back from the rear cockpit bulkhead area, and a long metal tube runs the length of the fuselage just below the spine to the rear to drive the elevators. This metal tube would run right through the middle of either of the hatch options, so..

Do I shorten the linkage and move the servo mounts back 12-14" so they are behind the proposed front hatch option OR do I leave in the original position and live with a metal tube running through the middle of a hatch?

Finally would the hatch cause unwanted extra structural weakness?

marcs

RE: Skygate Hawk - build (virtual manual)
 

Following the painting of the nosegear frame/formers, I mounted the nose leg to it and fitted to check it lined up centrally then marked the fuselage where the glue joints would be, removed and keyed these areas.
I opted to remove the M2 nuts and bolts from the nose door hinges as they were really fiddly to get to and adjust nicely, in replacement I used a length of 2mm carbon rod which was long enough to pass through both hinge locations and finish inside the fuselage just to the side of the nose gear formers. As the hinges are positioned inside the mounts in the fuselage the door cannot move out of alignment, and removal just requires the rod to be drawn rearwards. Two small notches need to be made in the base of the former to allow these rods to pass through.

Tackled the main wing phenolic tube as well. This is only attached on one side of the fuselage and the builder is left to attach to the other side, not an ideal situation I must say! Anyway, waxed the wing tube around 5 times with a general purpose furniture wax, inserted and fitted the wing. Clamped up the wing and taped it so the joint was nice and flush, mixed up some 9464 and applied it to the supplied carbon ribbon then wrapped it round the phenolic tube and fuselage (I keyed these up prior to this for a good fix) making sure the 9464 was well soaked through the cloth.

marcs

RE: Skygate Hawk - build (virtual manual)
 

couple more..

RE: Skygate Hawk - build (virtual manual)
 

Noooooo to the hatch! [:@] I think it would require a total re work of the model as removing that much of the fuselage will really effect the strength of the finished jet.

RE: Skygate Hawk - build (virtual manual)
 

It could do with a hatch but appreciate your point, I'll just ring you when the time comes to get to the turbine and you can lend me a hand ;)

marcs

RE: Skygate Hawk - build (virtual manual)
 

Boys settle ,we can think about more complicated matters that will increase costs later [:-]

RE: Skygate Hawk - build (virtual manual)
 

Hi Greg.

marcs

RE: Skygate Hawk - build (virtual manual)
 

Oh Oh! Behave.. The boss is here! :D

RE: Skygate Hawk - build (virtual manual)
 

Awww mate, and he'd just sent me the mechanism he's come up with to open and close it :D :D :D :D

http://www.patriotmill.com/backrig.jpg

RE: Skygate Hawk - build (virtual manual)
 

Looks a little under-engineered for my work - you bored with no toys to play with;)

marcs

RE: Skygate Hawk - build (virtual manual)
 

Now we have some Aeropoxy its gluing time.
The front formers are now all secured.
Next was the rudder & fin, two ply hinges, one piece of plastic tube, hollow length of wire, two rudder horns and a spare washer!
The plastic tube goes inside the holes in the ply hinges to act as a bushing.
First job was to line up the hinges (with bushing in place) and cut two square slots for the ply hinges, once done and on the advice from Jorg I used a small length of aluminium tube to slot over the retaining wire as it came out of the top of the rudder, and planned to glue this into the top section of the fin, which is hollow - effectively making another hinge and adding security.

RE: Skygate Hawk - build (virtual manual)
 

Tacked in the hinges and the new tip tube hinge with some 20 min epoxy and left to dry.
Once secure I marked up the position for the lower FR4 hinge, this requires a slot which was done using a sharpened junior hack saw blade.
Whilst I was trying to line up the slots and position this lower hinge in place I noticed it was difficult to get the hollow length of retaining wire through the plastic bushes in the ply hinges, even with the edges rounded off they were catching and not sliding through nicely,
after some deliberation I swapped this hollow wire for a solid piece which I was then able to file the end to form a nice rounded point, this slid into each bush with any problems.

The top of the fin where the extra tube hinge was fitted had slight bows in the edges as there was no support for them, so used some Aeropoxy to fill this area and clamped two pieces of wood to the sides to hole the edges while everything dries.
Added Aeropoxy to all hinges above and below the frame.
marcs

RE: Skygate Hawk - build (virtual manual)
 

Enjoying your build, quality stuff.

Cheers, Alex

RE: Skygate Hawk - build (virtual manual)
 

Gidday from down under.

Just ordered a Tomahawk Hawk - still a long wait, kit due March next year. It will be interesting to see where I end up with instruction manuals. I'm half way through a 1/2 scale Pitts S1 out of Exclusiv Modellbau from Germany. Same gig, DIY instructions but a nice DVD full of pics. I think I'll cope, and the quality of the products out of Germany always makes it a little easier to swallow.

Good luck with your build.

RE: Skygate Hawk - build (virtual manual)
 

Tobba, hi, agree with you on the quality side of things, it does make a difference. I too will be building a Tomahawk after this build, might even be along sooner than yours as I believe it was one of the first ordered.
With any luck you might have a few additional pictures to work from ;)

marcs

RE: Skygate Hawk - build (virtual manual)
 

tobba,

I believe I have the first Hawk from tomahawk due with me in December. Having spoken to Thomas you'll be pleased to know that there are no instructions - just a CD full of pictures :eek:

This kit is simply a Skygate blown up on a photocopier so having built a SG Hawk I can't see anything really tricky. Besides you'll be able to use this thread as a 'manual' for the Tomahawk kit too so get cracking Marc :)

Rgds,
Mark

RE: Skygate Hawk - build (virtual manual)
 

Started pre-assembly and trial fitting on the rear former set, comprising three formers, one supports the fin and the other two support the rails for the elevator pivot plates, in all they assemble to all act in supporting these key components. I heard somewhere that there were issues around fin flutter but was told this has been addressed now, however I did shape a piece of thin ply to flix to the top section of the fin former to add some additional strength to this critical area, it may not be essential bit for the sake of 10 minutes work it seems it cannot do any harm.

Started the 'grey out' of areas which are potentially seen, and makes them easier on the eye.

RE: Skygate Hawk - build (virtual manual)
 

Once the rear former set was complete I tack glued the rearmost two formers at 90 degrees to the rails, the forward most former which takes the fin tube needs to be free so that when the formers are fitted the fin can be adjusted before this former is finally secured. Trail fitted in fuselage and marked where to pre surface for good glue fixture.

Waxed up the rear wing tube and began the fixing of the phenolic tube, aeropoxy and glass tape are applied to one end, once dry the other end can be done, doing both is possible but I am not confident the waxed wing tube would release if both ends are glued at the same time! Yep call me what you want............

RE: Skygate Hawk - build (virtual manual)
 

Gear door cylinders supplied are really nicely made, swivel nipples on the base of the cylinder so the air tube can be routed in the desires direction. Also a 'stop' collet is also supplied which is a first, usually I have to remove the fixing on the end of the ram and slide on a collet so that the end position on the air ram can be set exactly where you want it - on these its already there - nice :D

The cylinders have a large hole at the top for mounting, M4 by the looks of things, so two choices here, bush out the hole to M2 or M3 or drill the ply cylinder mounts out to accept M4, I decided on the latter as there is plenty of meat on the ply mounts to take this enlarged hole.
Fitted the gear doors and hooked up the cylinders, attached the ply mounting plates, extended the rams to full throw and moved the cylinders until the desired max opening of gear doors was optimised, then positioned the ply mounts so the cylinder was at the best angle, and tacked the mounts to the fuselage (pre sanded for a good fix) - lining up both cylinder mounts took a while as its tricky to get hands in through the opening to apply cyano but patience prevailed.

Painted and mounted the small nose gear door cylinder to its mounting, and added air line. Fitted air line to nose wheel retract (4mm tube) and security wired.

RE: Skygate Hawk - build (virtual manual)
 

last two for now....

RE: Skygate Hawk - build (virtual manual)
 

I have been asked during this build by Ali to work on a tank and ducting upgrade, Ali who has experienced many flights on the Skygate Hawk, has found that finished examples with higher wing loadings, those over the 20kg weight fly significantly better than sub 20kg examples. In addition a better airflow through the jet would further enhance the overall abilities of this great jet.

The plan is to develop and make commercially available a kit to increase the tank capacity with a new 6.5 - 6.7L tank and associated mounting formers, and a fully ducted inlet and turbine system to improve airflow through the jet. In addition to the work on the Skygate hawk, this option will also be available for the new Tomahawk Hawk once it has landed on our shores. Ali is keen to make this an option that existing owners can upgrade to, and if required remove should the need arise leaving a minimal weight of components in the jet. Access will be a key consideration in this upgrade.

Ali's words "I had always thought that the model would benefit from a higher wing loading, more power and a cleaner ( Aerodynamically ) install. Other Skygate owners had proved this with heavier ( Over 20 Kg ) builds plus more power. Now all that was left to do was the instal part, and maybe mention that we are doing this with the new forthcoming Tomahawk in mind and the idea that if needed all of the bolt ons could be made removable and the model returned to the original lightweight spec if needed"

The plan is to move the tank up and above the ducting, which is really the only place for it. The tank will be a simple rectangular shape, possibly with baffles. Two formers will hold the tank in a cradle, with the x-braces that sit under the tank removable so full access to the turbine is possible once the tank is removed. These are early pics and more will follow as part of this build.

marcs

RE: Skygate Hawk - build (virtual manual)
 

Marc,

Looks good and agree with all the above and have spoken to Al about this before.

Put me down for the free prototype version on my Tomahawk :D

Is that going to be the location of the front 'support' former? If so, the tank front/pipes will hit the rear of the front cockpit. The higher up the rear fuselage section you go, the less anything can protrude.

M