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Re: Pieter Visser

Posted: Fri Dec 15, 2017 2:27 am
by Pieter001
I am waiting for some 30x30x5mm angle iron and neo-magnets to work on the landing gear. The magnets I plan to use for locating the correct place to drill the mounting hole, but we'll see how that goes once I get them.
NOTE: Magnets are of no use locating the correct place to drill as of course the metal gear hump attracts the magnets! works great on the e-glass sections... Pilot hole is the way to go;)
In the interim, I've started preparations for gluing the RH carbon fins skin in place, so lots of sanding on the skin and the fuss!!
marked and then sanded the RH carbon fin skin
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Re: Pieter Visser

Posted: Wed Dec 20, 2017 6:27 am
by Pieter001
It has been a busy couple of days and the great news is that my Whisper is finally on her own wheels after 241 hours of build, what joy!
Getting there was not clear cut. So let me start with the simplest way, I think at least, to get the gear legs and hole positions correct :)

Level the fuss in long-and-lateral attitude. I used a small workbench under the main gear layup and a rubbish bin with polystyrene at the back near the tail wheel. I used the laser to validate all the angles, canopy sills are the simplest here, but I've long since drawn lines in areas I need and use to level the fuss.
Once this is done one has to inset the gear legs, so both are level, as the fuss is level. This is done by determining how deep the gear legs are sunk into the main gear hump, which sounds simple, but as one cannot see through them, determining the gear leg hole position is rather tricky. Note that the laser works well here to see if the legs are at the same level and using the 4 axle attach holes at the bottom of the gear leg works well.
The best way to find the hole position in the gear hump is to drill a pilot hole in the gear hump on the face of it. I used a 4mm drill for this, but 3 will also work well. One can drill this hole around 60mm from the top of the gear hump. Using the 4mm drill back end once can now insert the gear leg and "lock" it in place by inserting the drill bit through the gear hump and gear leg hole. Masking tape on the gear leg will make it possible to put clear pencil marks on the tape. Mark the position where the gear leg exits the fuss while the 4mm drill bit is holding the gear leg (you may need to lift the gear so that it is flush with the gear hump all the way). This is now the DATUM mark to measure from, together with the pilot hole. Now insert the gear leg to the top where it "bottoms" out and mark this spot (we need to be at least 5mm below this point to prevent it fouling the top). We have our "green zone" between these 2 point.
Insert both gear and "lock" them in through the pilot hole with 4mm drill bits. Now use the laser to see how level they are. If your very lucky, they may be level, but likely they may need some adjustment. Decide which moves where (as close to the 5mm from the top mark as possible) and mark this position on the gear legs. Measure from the DATUM the distances and then measure this distance from the pilot hole. Mark this spot on the gear hump, BUT drill 5mm below this spot (as the pilot hole is 4 mm and the AN6 bolt is 9.6mm or 10mm if you drill a metric hole).

This method should produce the best result and I had to cover the first 10mm hole I drilled with a strong flox mix and drill again to level the gear. Level both gear first and then drill the 10mm holes! I first drilled the LH gear 10mm and realised my mistake later when I could not get the RH gear higher to level them :(

I've also fit the tail wheel, which was very straight forward thankfully.
On her own wheels!
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20171217_115202 Chris LH.png
1st attempt LH and RH not level
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20171217_115206 Chris RH.png
1st attemp RH gear level line out with LH
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Re: Pieter Visser

Posted: Wed Dec 20, 2017 6:57 am
by Pieter001
After correction the gear on and gear legs flush with gear humps and bolted on with AN6 bolts and nuts, all level and good :)
RH gear final with laser line
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LH gear final with laser line
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The tail wheel has some play on the spring, so I filled this in with flox so there is zero movement in this area.
Tail wheel removed with flox lines and package taped spring visible
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Re: Pieter Visser

Posted: Wed Dec 20, 2017 7:05 am
by Pieter001
A tip to get the AN6 nut on the AN6 bolt inside the gear hump, which is rather tight work space. I drilled 38mm holes on the inner edges of the gear hump, as per the instructions. I then used magnets on a size 14mm spanner and some masking tape. This then allows the washer to stick to the nut and the nut to the spanner with the tape preventing it from slipping out the back. Someone else needs to turn the bolt on the inside of the fuss, while you hold the nut in place and wait for it to "take" on the bolt. Once this happens and you are sure it has taken clean and well you can tighten it firmly. This is just temporary at this time of course.
2 small magnets with masking tape to prevent the nut slipping back to the magnets
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Washer now clings to the nut in position to make assembly simpler
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Re: Pieter Visser

Posted: Tue Jan 09, 2018 10:05 am
by Pieter001
The time has come to start the wing carry through spar box. This was my thoughts in December, as I was going to have a glorious 3 weeks of leave and lots of building to do :D

Sadly, this task is still ongoing and I've not completed it during my leave, although I've made good progress, life happens as usual and all my time was not build time. We had the best weather here in NZ, which one has to enjoy to the max when it comes around.

So first I made space and put 3 tables in place to put the wings on to level them. I am so thankful to have a garage with enough space to do this in! Really miss my hangar back home :(

Drilled the 6mm pilot holes at 90 degrees in the 2 spar planks, as indicated on the spar planks, after I aligned and clamped the 2 planks on top of one another. This worked out well.

I trimmed the planks to the indicated size and also trimmed the "depth" from 217mm to 204mm, as it would be too high to fit correctly in the fuss. The trimming of the spar planks is quite a task with the thick layup using a hack saw. I later switched to a the 125mm angle grinder with a 1mm steel disk: making a very "quick" cuts only around 1mm deep at a time and allowing a bit of cooling off time. I did this outside in a stiff breeze too as there are LOADS of fiber glass dust around with the approach. It is WAY quicker, that is for sure! One must ensure that there is no heat build up when doing this.
Wings on 3 coffee tables and tips on polystyrene block to adjust for incidence and dihedral
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Spar planks pilot holes drilled while clamped together before trimming
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Re: Pieter Visser

Posted: Tue Jan 09, 2018 10:28 am
by Pieter001
As I've lost a lot of build time with the relocation to NZ, I decided to have the wings constructed by the Whisper factory, which saved me a LOT of time and they look great too :)

The challenge I found is that with the wingtips on it is not as simple as setting the wings up in the wing jig to get them level and to determine where the wing spar runs. The 38mm holes are open at the root and available to put short 38mm tubes in and to use this method for leveling. However, I decided to mark the center line on the wing spar and the 38mm holes and to align all of this across the 2 wings, which will have the same result in the end, but is slightly easier to setup in my circumstance.

Using the laser to level the wing spar, spar planks and to set the incidence on the wings is pretty simple. I used the wingtip foam cut template to determine that the spar center in the wing should run at around 74cm from the aileron cut line (top of wing). Using the laser again, it was easy to line up the wings correctly.
LH wing at root with cord line marked and wing spar center line extended and marked on the root too
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RH wing at root with cord line marked and wing spar center line extended and marked on the root too
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Re: Pieter Visser

Posted: Tue Jan 09, 2018 10:37 am
by Pieter001
I then needed to set the dihedral. With the wings level at the center at ZERO incidence, measuring and setting the dihedral is not too hard. I setup the left wing with the wingtip 18cm higher than the center and then used the laser to set the level of the RH wing. Setting up the laser and then swinging it around by 180 degrees allows one to measure the height of the wing tips.
LH wingtip after dihedral of 3 degrees was set
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Set the RH wingtip, using the level to be the same height as LH wingtip - Laser not easy to see with the flash here. One can see a small polystyrene block under the wing, on top of the big block, which is used to set the incidence of the wing to be ZERO at the root
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Re: Pieter Visser

Posted: Tue Jan 09, 2018 10:43 am
by Pieter001
Using a new 41mm hole saw blade, newly purchased with the arbiter (no drill bit, but a 6.5mm seemed to work just fine), I then drilled the wing bolt holes. This was after I used a long 6mm drill bit to drill the spar plank pilot holes into the wing spar, FROM both sides. It is important to drill from both sides and to be as square as possible. The laser again works well to assist with this and I used a black permanent marker to draw the square lines on my hand drill.

The bronze bushings need to be trimmed in a lathe to the desired length and I am eagerly awaiting the engineering shops in town to open so that I can have this job done. After measuring it turns out the left bush needs to be 98mm and the RH bush 101mm in total length and speaking to Chris at Whisper, he recons the 3mm is marginal enough so that I'll have both at 101mm. Rule is rather a tad too long than too short, meaning the bush has to be wider than the wing spar and the spar planks must not foul the wing spar.

The joystick bolt hole, for a single control stick, is drilled in the center from left to right and 40mm from the top (or 44mm if already wrapped). I'll do this during the week :)
LH wing bolt 41mm hole drilled
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Trial fit of LH wing bolt using 3mm plexi as spacers
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Trial fit of RH wing bolt using 3mm plexi as spacers
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Re: Pieter Visser

Posted: Tue Jan 09, 2018 11:05 am
by Pieter001
While waiting for the engineering shops to open, I decided to glue the RH carbon fin skin. This replaces the standard fiber glass skin and the RH and LH skins combined should save around 800gr of weight in the tail section, which is fantastic! It came out beautifully. The Whisper factory did a great job with these carbon skins and they are a joy to behold. After marking and sanding of all the areas, I vacuumed and then washed all areas with acetone and a brush. I then painted a layer of mixed resin without flox on the fin skin in the bonding areas to ensure good adhesion. I then mixed around 200gr of resin with cotton flox to get a firm consistency and applied this liberally to the skin and the fin bulk head support structures, after which I used a few small screws to get the fin positions correctly. These screws was used to "dry fit" and position the RH and LH skins and to check for alignment etc. Once the RH skin was in position correctly, I drilled 2mm holes as required and used more small screws to ensure that the wing is fit properly and to push out the extra flox, which was a LOT!

I am very happy with how this turned out and I pray I never have to try and get this carbon skin off, as it will be near impossible!
RH fin skin glued on securely with screws removed, but the holes are visible
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RH fin skin above the H-Stab support. The painted layer of clear resin is visible on the carbon
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Re: Pieter Visser

Posted: Wed Jan 10, 2018 6:36 am
by Pieter001
The engineering shop will only open on Monday the 15th, so my bronze bushings are lying idle and so am I :( Thus, decided to do the strengthening of the rudder attach points, the Hstab area and I also decided to add a little more strength to the area where the elevator pulley will be mounted, before I make the hole for it.

I am using 300gr bi-ax carbon for all of these sections, so I'm using 5 layers instead of the 6 layers of 410gr bi-ax E glass. Thus the layup weights less, but it will be super strong ;) !

I'll likely use only 4 layers on the rudder attachment points, but that will be for tomorrow :D
Single layer 300gr bi-ax carbon over the area where the elevator pulley will be attached. This area was already strengthened with E glass, but I'd like this little extra to make sure the elevator can deal whatever loads may be put on it
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5 layers of 300gr bi-ax carbon over the Hstab attachment points. I've covered the holes drilled here with tape on the opposite side, before doing the layup
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Pic of both carbon layups with peel ply finish
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