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Member postings for Chris North 3

Here is a list of all the postings Chris North 3 has made in our forums. Click on a thread name to jump to the thread.

Thread: C No Ohmen
04/09/2019 01:33:48

Peter and Trevor - thanks for the feedback. The ESC is just too long to fit into either fuselage bay but i will shoe horn it in when I install of the electronics prior to coating.

For now I have made a start on the cowl. The spinner ring has been sanded to shape. I guess this does not need to be overly accurate but to get the best profile I could by hand I positioned the ring so that the required outer edge was level with the building board and then I stuck a pin through the center of the plate to hold it in place. This way I could rotate the ring on the center pin in order to get a consistent sanded edge.

20190831_154351.jpg20190831_154357.jpg

With that done I cuts some cross hatches in the center area in order to roughly open it up and then used the dremmel with a sanding drum to get the best internal circle I could.

Unfortunately I forgot to take photos of the rest of the work so I will upload these next time. A piece of 9mm soft balsa sheet was cut just over size using the plan as a guide and reference lines were then added for the center line, thrust line and the edges of the ventilation holes. Using these guidelines the spinner ring was glued to the front of the sheet and left to dry.

The cowl sides are made from 1/2" sheet but since I only had 9mm, I cut enough 9mm sheet to make both sides and then laminated a piece of 3.5mm sheet on top. Just to make things harder for myself, the 9mm sheet was not wide enough for the cowl sides given the required grain direction and so a second lamination was made up and but joined to the first to make a suitably wide section.

These will now all be dry and ready for cutting tonight but unfortunately work is once again getting in the way and forcing travel. So unfortunately, no work on the Ohmen for the next couple of weeks.

I am sure that when this is finally finished more than half the build time will have been the result of suspensions for work and holidays!. Maybe I should stick to ARTFs in future...wink

Anyway, before I go, another quick question - what kind of stand-off is required between the front of the cowl spinner ring and the back of the spinner plate? I'm assuming 1.5mm is ok but is this particularly critical? I am assuming the best way to achieve this is to install the propeller and spinner and then pack the required gap with some scrap 1.5mm sheet.

'Til next time!

02/09/2019 03:00:22

Since the motor was mounted I connected the ESC and tried to see where this could best be positioned. I assume that it is meant to be attached to the bottom of the battery plate (which I have not glued into position yet) in the front bay - so that it can be accessed when the cowl is removed but everything seems to be a bit of a squeeze. Also once the bottom sheeting is installed and the battery plate glued in position this whole area is going to be almost impossible to access.

If Peter or anybody else has a picture of their Ohmen battery and ESC set-up then that would be appreciated for a bit of guidance. Note that I am using the 4-max recommended set-up20190901_214519.jpg

02/09/2019 01:46:18

Next the wings were given a good sand and the wing tips shaped to blend in to the ailerons....I forgot to take the before shot but here is one of the finished tips. I have probably made life more difficult for myself when it comes to covering the wing but I like the way it looks so we shall see how we go.....20190831_145807.jpg

Next up I attached the motor so that I could start to think about the cowl. As yet I have not attached the bottom sheeting to the front of the fuselage as once I do there will be no access to the from section. With the motor in place it was obvious that, as noted by Peter in his original article, that the motor shaft and securing bolts could cause an issue for the battery and I decided to add a simple box arrangement. A balsa box was made up and glued into position and then a piece of 2mm ply was glued to the top. Hopefully this will stop the battery in the event of an untidy landing.

The box in place....20190831_141503.jpg20190831_141522.jpg

and with the ply top installed.....20190831_141710.jpg

02/09/2019 01:33:10

This weekend the focus was on tidying the airframe up so that we can move along to the finishing stage.

So - first up the fin support blocks:

the laminated strip tacked to the jig, before sanding ...20190829_220119.jpg

and after..20190830_213120.jpg

the jig removed from the fuselage...20190830_213235.jpg

and the blocks removed from the jig...20190830_213818.jpg

and trial fitted to a loose tail just to see how they fit....20190830_214246.jpg

A little bit of trimming required to make sure there is no clash with the elevators but not bad

30/08/2019 10:56:59

Hi Peter - good spotting - yes everything is only temporary at this stage - the hinges are all slotted and set but nothing glued. I will cover each item separately and then cut the covering at the hinge slots before final assembly. At the moment I have not beveled the flying surfaces either as I plan on doing all this on the final sanding and tidy-up before starting to cover.

I have to admit that having everything slotted together not only stops me from loosing bits but it also allows me to pop it all together now and again to convince myself that it is coming along.

I do like the look of this plane but keep wondering whether it would look twice as good as a biplane - maybe something for the future...smile p

Thread: Moon Dancer 2
30/08/2019 10:49:52

Looking great Peter and plenty of great photos to help us along. Following with interest.

Thread: C No Ohmen
30/08/2019 01:17:15

Thanks Peter - I was heading down the right path but like your idea of a dummy jig for the blocks so will borrow that idea.

Hi Dennis - as Peter has said, everyone approaches a build differently and nothing is right or wrong. I will get everything finished into its separate parts and sanded down before starting any covering this way I can make sure I have done everything!!

Last night progress saw a tail jig made up for the fairing blocks. I didn't have any large enough block balsa and so have laminated up some offcuts from 6mm soft balsa using superphatic so that they will sand easy . The jig has been attached to the fuselage with a small drop of cyano and the blocks attached to the jig in the same way - hopefully the drop is small enough to allow me to remove it all easily later.

To finish up for the night I found an offcut of 1.5mm balsa that was just enough to cover the bottom of the rear fuselage. This was attached with superphatic, again to aid the sanding process, and all taped into position overnight.20190829_220147.jpg

Looks like there could be some sanding happening over the weekend....

29/08/2019 01:44:30

So the plan now is to use a scrap piece of balsa sheet to represent the fin and to attach and shape the support blocks.

So a question to anyone who may be following : do you normally glue the finished support blocks to the stabilizer or the fin (or both) before covering or do you cover all items separately and then glue them together afterwards (ensuring balsa to balsa bond of course)?

Also a question for Peter - should the leading edges of the stabilizer and fin be rounded off or left square? I am sure it will look better rounded off but does it make a lot a difference as far as performance is concerned?

Thanks in advance

29/08/2019 01:37:48

Now that the fuselage sheeting is essentially finished (it needs a bit of sanding and filling along the joins) I thought it would be a good time to move onto the fin support blocks.

I don't want to glue the stabilizer and fin before covering as I can see that this will make covering more difficult but I do need to position the tail so that I can sand the support blocks to shape.

Since I still have the paper template on the tail I used the center line to ensure the tail was pushed up against F9 and centered over the rear fuselage. A T-pin was inserted through the stabilizer and the support plate to hold it in position while still allowing it to pivot slightly. A tape measure was used to verify the check the distance from one tip to the centre point at the rear of the hatch. A minor rotation was all that was required to get both sides equal and then a second pin was installed at the front of the stabilizer to fix it. The plan being that these pin holes can now be used to reposition the stabilizer once the template is removed.

The templates had been attached using pritt stick and so a quick wetting of the paper and the whole template was able to be scrapped back easily. While the paper comes off no problem the glue gets sticky again when wet and so this rubbed off and then given a quick sand with a fine sponge sanding block.

20190828_215403.jpg

While I was at it I went ahead and removed the templates from the stabilizer, fin, and elevators.

29/08/2019 01:20:31

So a quick check list of items left to do:

  • attach bottom fuselage sheeting
  • add packing block below wing bolt retainer
  • attach tail feathers
  • add & shape support blocks to side of fin
  • build cowl;
  • cut top and bottom openings in hatch cover
  • attach battery tray & velcro
  • add all electrics;
  • finish shaping wing tips;
  • sand, assemble, stand back, smile and enjoy;
  • cover and set-up for maiden;

Well that doesn't sound too bad...

29/08/2019 01:12:46

Measure, cut, glue, wet, bend, glue hold, repeat.....

20190828_211257.jpg20190828_211306.jpg20190828_211323.jpg20190828_211355.jpg

I have to say that I am quite pleased with the way the sheeting has turned out. There are a couple of spots that i could have done better on but all in all in it is looking neat and tidy. The only thing I am a little worried about is that the fit is nice a tight and so I am not sure if this is going to be a problem once I apply the covering - i.e. should there be a 1 mm gap to account for the film covering at the joins?. I have the change to loosen everything off a bit when sanding prior to covering so we will see.

27/08/2019 02:55:45

Back at home and back at the bench. Only had an hour this evening so spent the time adding the next piece of fuselage top sheeting.

First I taped piece of thick paper to the fuselage

20190826_212739.jpg

...then rolled it over and marked the center spine...

20190826_213219.jpg

..removed the paper, cut to size, taped to the edge of a piece of 2.5mm sheet and cut to the template..

20190826_212318.jpg

..using cyano, I attached the sheet to the top of the fuselage sheeting and let it set..20190826_214118.jpg20190826_214130.jpg

....the sheet was then wetted on the outside and the water allowed to soak in. After a couple of minutes the sheet was slowly rolled over the formers until it aligned with the spine. The sheet was released, cyano added to the formers and the edge of the spine and the sheet rolled back into position. The fuselage was turned upside down and pressure applied until the glue was dry and the sheet was attached...20190826_215045.jpg

...leaving me with a nicely rolled top sheet... 20190826_215107.jpg20190826_215130.jpg

Now I just need to repeat for the second side and then trip up so it is flush with the fwd and rear formers. Since I have to try to align two edges on the next piece of sheeting I expect there may be a rough join along the spine however this can be filled and sanded before covering so no need to worry to much about aesthetics at this point.

I'll see how I get on this evening.

19/08/2019 07:27:27

With the sheeting in place both sides were then trimmed flush with the base of the hatch cover. To do this a spare piece of 6mm strip was placed next to the hatch and was used as a guide for the box cutter. This way the sheeting was neatly trimmed and only required a quick sand to bring it flush with the base of the hatch.

I forgot to take pictures of the sheeting process but here are a couple of the final sheeting before trimming and the trimming process

20190817_064507.jpg

20190817_064517.jpg

20190817_064733.jpg

19/08/2019 07:23:13

Small bit of progress before heading to the airport....

I decided that I would make a start on covering the cockpit hatch cover as a bit of a test for the rest of the fuselage top. In an attempt to cut down on waste balsa I used a piece of scrap paper to assist with cutting a template for the sheet balsa. So taping one edge of the paper flush with the bottom of the hatch base, it was wrapped around the formers and then the center line of the spine marked. The paper was removed and its size marked onto a sheet of 2.5mm sheet

Since I had used 6mm square balsa strips as the hatch alignment rails, I also added 6mm to the width of the paper template so that the sheet when cut would reach the bottom of the guide rails.

A bead of cyano was run along one edge of the hatch cover and the balsa sheet was placed up against it. With the extra 6mm width the sheet was able to sit on the work bench and be held vertical against the side of the hatch using a couple of squares.

Once dry the outside of the sheet was throughly wetted with water and left to soak in. After a couple of minutes the sheet was gently and gradually pushed over the formers towards the center spine. Pushing a little at a time allowed the sheet to form without breaking.

The sheet was then released and a bead of cyano run along the top of each of the formers and along the edge of the sheet where it touched the spine.

The hatch was turned over and rolled against the bench, so that the sheet was tightly wrapped against the formers without any gaps, and was then held until the glue was dry.

Luckily the first sheet ended up just next to the latch lever and so no trimming was required to clear the latch mechanism.

The process was repeated for the second side however this time the sheet was started from the center spine to make sure the join was nice and tight. A notch was cut in the sheet for the latch handle and then the sheet wetted and rolled around to the hatch bottom edge.

15/08/2019 06:51:58

And since I was now more comfortable with bending smaller wire I used the same approach for the main under carriage legs. To get the lever arm to help with the bending I used a single length if wire and bent a leg at each end!

All I need to do now is to cut them to length and they will be ready for trial fitting

20190814_213552.jpg

15/08/2019 06:10:42

While at the LMs i did contemplate getting a new bender but I'm a bit of skin flint and can't abide buying things twice so decided to persist.

A quick sharp jab of the palm had the wire bender free and so I decided to try again, this time with the thinner wire.

I found that if the hobby vice is clamped as hard as possible to the desk it will eventually stop rotating when a load is applied. The distortion to the wire bender meant that even with the thinner wire it would tend to run up over the wire but I eventually worked out that instead of trying to do all the bending with the handle, if the wire is pulled around with one hand in the direction of the bend, the handle then only has to do half the work and forms the bend quite easily.

Wish I had found this out before damaging the bender!

Anyway, a new elevator joiner was made up, trimmed to size and then the elevators notched so that the joiner sat flush with the hinge surface. Very straight forward and boring for most i am sure but since I took the photos, here they are..:

Joiner bent to shape and locations for drill holes marked...20190814_213346.jpg

Hole drilled slightly under size, grove cut to accept wire and little bit extra taken at hole location to account for wire radius...

20190814_213258.jpg

Wire inserted and groove adjusted until wire sits flush...

20190814_213322.jpg

Re-attach elevators and double check location of second location hole. Remove and repeat grove preparation for second elevator...

20190814_213221.jpg

Jobs a Good 'un

20190814_213143.jpg

20190814_213109.jpg

15/08/2019 05:54:03

Very little progress this week as there has been no time to get to the building board plus I came across a problem with the wire bender which I put on the back burner

I think bending 3mm wire with the K&S mini wire bender is most likely fine if you have a decent vice but since I'm using a small hobby vice I think it is on the limit. The problem being that it is hard to clamp the hobby vice tight enough to the table to stop it spinning when trying to bend the wire. This means that one hand was required to support the vice and thus only one hand on the wire bender handle. For thin wire this would be fine but 3mm is at the limit and so I have slightly elongated the pin hole in the handle. This means that there is now slop and so the handle tends to ride up over the wire instead of bending it.

Here is the result of trying to bend 3mm wire one handed! Yes it is well and truly wedged!

20190814_204306.jpg

So, frustrated the thing was put aside for a day or two. In the mean time a trip to the LMS was made to pick up some 2mm wire (couldn't get 16SWG) for the elevator joiner.

08/08/2019 11:40:49

Thanks for that Peter - I most likely didnt see it as I have cut part of the plan up. Still it is not installed yet so no problem. This was all the wire I had so I will have a look at the local shop after the long weekend.

Thanks again for keeping an interested and helpful eye out

08/08/2019 02:33:51

As a bit of a change and to make sure I keep seeing progress I moved on to the tail feathers.

I had already cut out the horizontal stab and elevators from 5mm ply sheet and so first up I installed the hinges using the trusty hinge slotter to make sure the hinges were centered. Practice must make perfect as the slots were much easier to make this time and the hinges a nice tight fit.

Couldn't resist getting a feel for what it is going to look like..

20190806_214849.jpg

It looks a bit strange just now but once I have completed the fin and rudder I will take all of the paper off of the parts and sand back.

Next it was time to take the scalpel to the plan again so I could use it as cutting guides for the fin and rudder. The rudder was no problem however the fin dis not fit on the 5mm sheet I have and so the sheet was butt joined to create the correct width. There should be no issue with glue strength but either way the butt join has been placed so that it is at the front of the fin and will be supported by the thickest section of the fin cheek blocks.

20190807_220242.jpg

Putting that aside to dry I was trying to find something simple before finishing for the evening.

On the Batty build their was only a single elevator and so no need to join separate halves. Ohmen requires a standard wire joiner and so this seemed like the ideal item to look at.

Previously I have always struggled with pliers to bend undercarriage wires and so this time, given that the plan calls for 3mm wire I decided to get a small wire bender. 3mm wire looked a bit big for the elevator joiner and so rummaging through the spares bag I found an old set undercarriage legs I had made to suit some retracts in a flitetest spitfire which were slightly thinner at around 2- 2.5mm. One end was already bent to take the wheel and this turned out to be a perfect fit for the elevator.

So with a bit of thinking and some trial pulls to see which way it would bend (!) I set up the wire bender and bent the second 90 deg into the joiner. Wow so much easier than struggling with pliers.20190807_220053.jpg

20190807_220216.jpg

So feeling brave and since I had everything set-up i thought I'd try bending the undercarriage. Well the vice I have is a small desk mounted one and I have to say that it is not ideal for bending 3mm wire which is at the limit of this little bender I got. The main problem is that the vice is not stable enough and so any decent pull on the bender handle turns the vice on the bench. Holding it stead with my left hand did help but reduces the amount of pull that can be given. For sure the 3mm wire was a lot harder to bend but when I got the hang of it I die manage manage to make some progress.

All in all not bad for a first attempt. Anyway we are away for the long weekend so I will finish this off later next week. I can tell already that the trick is going to be bending the second leg so that it matches the first! Any tips and hints would be most welcome! 20190807_220147.jpg

05/08/2019 10:11:56

Thanks for the tips Peter - I did notice on the plan that the ply plate was above scrap balsa. At this stage I have only installed the ply plate and plan to add scrap balsa next to provide packing / spacer between the top of the wing and the ply plate. I don't always seem to build in a logical manner which I am sure makes life difficult for myself. Still, every build is a learning exercise and so I am hopeful that all these mistakes and work-arounds will lead to a more streamlined build experience down the track!

When getting this plan copied I also made a couple of copies of Peggy Sue 2 just in case so you never know..mind you there is still plenty to do on this one first.

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