kirkj

My Feedback: (61)

be sure and share (with pictures) the things you do to add strength. weight is not a concern of mine either and I would love to beef mine up as well.

Kirk

tobba

Will do Kirk.

Marc to confirm again we purchase the ducting/tank upgrades through Ali?

Thanks

marc s

Yes indeed, Ali exclusively distributes these kits.

marcs

Remco45

@ Countryboy: thanks for your commetns. You are most likely correct in that in your example the two servos on the right cannot deliver their full force to the bottom left one helping it with overpowering the top left jammed servo. For that, i suppose all four of them should be placed behind each other (SWB-style) and coupled by hard pushrods. However, the 2-servo setup will not work when a servo fails limp, the 4-servo setup will provide full control.
I've questioned quite a lot of other modellers and although it seems that good quality servos rarely fail, it seems that failing limp happens more frequently than failing jammed.

@Tobba: did you use the original 3-servo SWB-tray or did you modify it?

Regards,

Remco

tobba

Gents,

Started my build, to the distaste of my BVM Mig which is 90% finished and now taking a back seat due to the excitement.

Can anyone enlighten me here... besides acting as a shim plate is there any other reason for the nice glass plate? It holds the pivot arms nicely in place when you attach the stab too, but I don't see much else going on...

Thanks.

tobba

Hi Remco, I used the SWB system standard and it works well. Great in a pull pull scenario but not sure here. This is a tricky one. I spose for me at the moment, a more simple approach with 2 servos and less to actually go wrong seems better. Understand the pros and cons but if a servo does lock I'm thinking you may get a little more throw to try and land from the 2 servo setup?? I'm sure this will be argued in many directions which is probably a good thing.

Wow there's a few wide holes in the assembly process which I'm sure will unfold... I got the finished cockpit which is amazing, but not too much when it comes to the assembly of the main structures. Any info I'm missing here?

Thanks.

marc s

Tobba,

Don't believe so, I locktited studs in the pivot arms which makes alignment easier without using this template guide. 4 Lock nuts secures stab unit.

marcs

tobba

Thanks. Snap, I'm in the shed now making 2mm carbon plates for the pivot arms to sit on for a better footprint.

I like the stud idea, will follow suit.

schroedm

My Feedback: (1)

Chaps, just use the thin glass plate. Keeps everything nicely lined up and 4 bolts are quicker than 4 nuts and washers each time. Oh, and there's no need to enlarge the footprint, everything works fine.

Besides, you'll raise the stabs up which will likely interfere with the cover/scale bacon slicers!

Mark

marc s

Mark,

On the SG kit I am working on the spacers under the pivot units were needed to get the stab to the correct height, there were not intentionally added. I guess each kit is slightly different.
On the template thing I am still not sure how it can keep everything aligned if it has nothing into which to fit to 'hold' things in place. The pivots have M4 holes in them, so rest the template on these so the holes align, then if you are really lucky you wont move anything as you lower the stab down, tried that before I added the studs - real mare!
With studs the unit just slips over - self aligning, as for the 4 nuts well not sure a few minutes makes that much of a difference, might have done at LeMans

marcs

Remco45

Many interesting possibilities here.
As you can see from earlier postings, I've decided to switch the stabilizer pivots around and make the bacon slices pivot in tracks.
According to Andy, the fiberglass plate has no other purpose but to protect the underside of the stabilizer and to raise it to the required level.
Hence I just cut the two strips out and glued them to the stabilizer.

Aileron and stabilizer hinge covers
Glued the rear parts in place as there is just enough room to get access to the screws and nuts.
The front parts are made removable.
To cope with the slanted flap hinges on the wing, glued some hard balsa to them and used a small sanding block to obtain vertical sides.
Just sanded about 1 mm further inward and covered them with 1 mm ply.
Glued some hard balsa to the tips too as the thin material makes them wobbely.

Regards,

Remco

ceffi

Hello
here some pics of the Hawk from my friend.
The best one I have ever seen.

Christian

marc s

Very nice indeed, needs a pilot though!

marcs

Remco45

Main gear doors: the small ones

When asked, the manufacturer gave a good reason why they don't apply markings or pre-drill the required holes for the small doors.
The tolerances in the wood, location and thickness of vacuum-formed wing parts etc. are just too large to enable precise location in advance.
Some very carefull modelling is needed here, so MarcS came to the rescue.
Once again I would like to thank you for your SG build virtual manual.
The installation of the small gear door proved to be a lot easier thanks to your tips, tricks and the now well known Scully-touches (see his page 13 and 18).

The Tommyhawk prototype originally contained a one-piece part from which all three gear doors had to be made.
Cut off the large doors and installed them in the fuselage as per Marcs manual.
I will wait with the installation of the middle parts until the gears and the covers are ready (see Marcs manual page 18).

From the first Tommyhawk production model, the small gear door needs to be discarded and replaced by an ABS part which has already the hinge locations marked on them.
Unfortunately, the opening in the wing was made for the original part, so the gap at the hinge side is too large and needs to be filled later on.
Andreas told me it would probably be better to replace the ABS door by a fiberglass door, so started with that and glued the three fiberglass part on.
I did not copy the top side of the door from the ABS part, but left it straight according to the opening in the wing.
Once the door is in place, by opening it you will be able to see how it should be trimmed.

To enable removal, the M2 screws are replaced by two sockethead M2 bolts. Also prepared two lenghts of M3 thread.
Note that the one near the leading edge is slightly bend due to the drilling angle in the wood.

As per Marcs instructions, first make the hinge near the leading edge.
Important: do not glue the ball sockets and the threads together. Both ball sockets must be able to rotate around the M3 thread during door movement so a drop of oil should be applied.
Trim the wing opening as required; the initial gap is large but will be filled up partially to make it look scale later on.

Next, attach the second ball socket to its hinge and align it carefully with the hinge arm and the door.
Carefully put the door in place: the opening of the ball socket almost touches the wood, and mark where the second hole should be drilled.
Insert the second M3 thread and put the door in place.

By opening the door carefully, you will be able to see how the door and the hinge openings need to be trimmed.
Ideally, positioning and trimming needs to fulfill three requirements: in closed position, the door should be flush and have even gaps; in open position, it should be parallel to the gear leg and finally it should be in line with the flight direction. This last requirement proved to be the most difficult...had to give up a few degrees otherwise the doors would not close.

Once everything seemed allright, glued the door in place using some 30 min epoxy. This allows some time to make final adjustments before taping it into the correct position with duct tape.

For the other door, just copy the basic trimming of the door and the openings in the wing skin.
I also copied the leading edge hinge position on the wood, but for the second hinge I carefully marked it according the Marcs procedure.
Needed about four hours for the first door, just 2,5 hours for the second one...

The gaps will be filled and adjusted later on.

Remco45

Remco45

More pictures

tobba

Guys,

In looking at the supplied Powerpoint reference supplied with the kit and applying my best translation skills ie:bablefish, does everyone agree the stab centreline is the rear hatch cover joining line?

The german was: Messpunkt + Nullpunkt ist Endleiste / Höhenruder zu Deckelebene.

Thanks.

Remco45

@ Tobba,

Yes, zero is when the most inward part of the stabilizer trailing edge is in line with the rear hatch cover.

Regards,

Remco45

kirkj

My Feedback: (61)

question:
in reading through this thread and the Skygate thread it seems that everybody mounts the aluminum louvers with the raised vents to the outside of the plane, then i have seen pictures of completed planes where the raised vents are to the inside of the plane (like a NACA duct) which is the correct way to mount the vents?

marc s

These vents face 'inside' - as per the SG hawk thread build......

marcs

Remco45

Sideways opening canopy

The D4S mechanism to modify the canopy into a sideways opening canopy is based on a fully assembled plug-in canopy.
After studying the Hawk cockpit pictures, I opted for a different approach.

First, the hinges were mounted on the RH cockpit side wall with the 2 mm rod and the canopy in place to ensure correct alignment.
I will replace the heavy 2 mm rod with a stainless steel 2 mm tube later on.
Glued the upper hinge parts to the canopy frame. The frame sidewall is then strengthened using a 15 x 5 mm wooden strip along the entire length.

Made 4 lock brackets from some spare Magnesium T-strip which are mounted on the LH cockpit sidewall.
After placing the canopy, the LH side of the canopy frame is also strengthened using a wooden strip, which is glued just above the 4 lock brackets.

Remco45

Canopy lock mechanism

Such a big aircraft needs a real functioning canopy handle too: the supplied plastic part is 4 mm too short anyway.
The mechanism is basically copied from the Hawk drawings.
A carbon fiber rod along the entire LH canopy sidewall contains four sort of "Z-shaped" hooks which pass through the Alu L-strp into the four lock brackets.

The handle was made from brass and Alu parts.
A small plate to transfer the circular movement from the handle to the rod is required as the rod only alows horizintal movement.

The second and third picture show the handle and locks in closed and open position.
All parts can be disassembled if required: easy for maintenance or to...ehh...ahum...correct errors.
At the rear end of the rod a pull spring is attached so the canopy locking mechanism is spring-loaded closed.

marc s

Remco,

Clever stuff here, love the catch -

marcs

marc s

Might be worth adding a small spring to maintain some tension in the locked position - just in case!

marcs

Remco45

Canopy frame corrections

After the hinge and locking mechanism functioned as required, the canopy frame needs to be prepared for glueing in the acrylic part.
Normally, I would keep off glueing in the acrylic part as long as possible, but...
On the real Hawk, the canopy stays in any opened position after releasing the spring-loaded handle.
Where the canopy devider frame connects with the RH canopy side wall, it is connected via a bracket to a gass spring. A bowden cable coming from the canopy handle operates the a locking device on the gass spring. On the first picture you can see these parts.
So, another challenge awaits!

Because our canopy is a lot less stiff, I need to glue in the acrylic part and thereafter the devider frame to stiffen it all up a bit.

So, before all that, the canopy frame needs to be prepered as much in advance as possible.
This includes (for me) some scale details such as the plating on the outside.
Also, the left hand side of the frame is less high than the RH side!
Just like on the real aircraft, the gap is coverd by L-shaped strips which are glued onto the RH cockpit side wall (sorry for the bad picture).

Remco45

Glueing in the canopy

As I've never made such a large canopy, I took several days to ask around for the working method.
Decided to use the super magnet (rare earth magnets or Neodymium magnets) method using Formula 560 canopy glue.
This proved to be really easy!

First, the canopy frame was placed onto a few thick books to raise it high enough above the work bench.
Placed the canopy over it, positioned it correctly and marked the forward and aft mold centerline onto the acrylic part for reference.
Taped it down and using a permanent marker went around it to mark the correct form.

Using flower scissors (thanks Marc) cut away all residue.
Placed the canopy in the frame from above (the frame can still be bend a little) as this will minimise any scratches.
Using the super magnets, started fixing form the top center of the forward and aft frame downwards, then along the sides.

Glue was put into a plastic syringe with a very thin plastic tip (these are used to wash out dental wounds).
Removing about 30 cm lenghth of magnets, glue was injected after which the magnets were replaced and any residue was wiped off with a moist cloth (warm water).
Use very little glue as it is quite thin and will climb up!
After the entire frame was done, it was placed onto the aircraft to dry in place as to prevent any twisting etc.