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Member postings for Martyn K

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

Thread: See-through OS wankel rotary engine running slow-motion
16/05/2018 09:56:34

Brilliant - thanks

Thread: Reading the wrong frequency...??
15/05/2018 17:09:30

It may be that the bandwidth of the Scanner is incorrect. If its set to WBFM, it could settle anywhere within the slope of the detector. The spacing between 35MHz channels is 10kHz but the transmitted bandwidth will be less than that

Martyn

Thread: Paint... Acrylics for spraying - advice please
15/05/2018 16:20:25

Thanks Denis

I have never heard of Acrylic thinners, I must investigate. 15psi is quite low pressure, much lower than I am used to so something else to try

Martyn

15/05/2018 13:40:54

Probably not a bad idea Don, but doors don't have a multitude of scale detail.

My worry is regarding the mix of screenwash and check that I have actually got me facts correct... I don't want to ruin the model or have the paint bubble or craze because I misread something

Thanks

Martyn

15/05/2018 13:32:55

Hi all

I need to paint a couple of models and I would like to try some Acrylic paints.

I read in a thread here somewhere that B&Q will mix up Valspar paint to match a full size colour. However, I need to prime a model or two (1/4 scale glider and the Chippie) with White undercoat/Primer first.

In that thread it was suggested that the paint can be sprayed (using an automotive spray gun) with the paint thinned with screenwash.

I have bought a litre of Valspar Acrylic white primer/undercoat and 5l of screenwash. Before I go any further can anyone provide me with a good mic recommendation and any gotchas I need to be aware of? I really don't want to screw this up..

 

Thanks

 

Martyn

Edited By Martyn K on 15/05/2018 13:34:34

Thread: Peterf's 1/4 scale Falcon Models Tiger Moth
14/05/2018 08:48:49

Absolutely fantastic. Well done Peter..

Thread: Martyn's Dalotel
10/05/2018 09:09:18

Thanks Chris

Martin, there is a bit of final fettling on the rudder before it gets covered but its about right.It does have a clight bevel/curve on the rudder, the fin edge is square

Martyn

09/05/2018 15:25:21

A little bit more progress. Having spent quite a bit of time trying to sort out the undercarriage doors I think I have finally succeeded to get it almost right.. The problem is that the doors need to open and maintain alignment with the the oleo. Sounds straightforward except my retract units are not angles forward, but the legs are.. Using the same mechanism that was used on the full size, the doors sit higher on the wheel when retracted, but when lowered they move downwards and outwards - if that makes sense.

5 attempts to get the left leg lined up the right leg was right first time. It means that the hinges for the door need to be raked which means that they are very slightly skewed inwards when extended, but that is a compromise I can live with..

The video show the operation but basically, the link pin is set so that the door is pulled closed when retracted, but as it extends, because the door hinge is further out that the leg hinge, it pushes the door downwards and outwards.. Really pleased with that.

Ailerons have been built and I thought a couple of bare bones shots would be worthwhile..

bare bones2.jpg

and

barebones3.jpg

and

bare bones1.jpg

The angled wingtips have also been finished. Today I have wired in the aileron servo extension leads and sheeted the bottom of the wing.

Quite pleased with this..

More to come

Martyn

Thread: Better late than never Chippy
09/05/2018 11:17:35

Very nice indeed

Martyn

Thread: Balsa USA Sopwith Pup 1/6 scale
08/05/2018 10:29:05

Brilliant.. Nice to see a successful maiden. Looks lovely in the air as well

Thread: Peterf's 1/4 scale Falcon Models Tiger Moth
04/05/2018 13:57:41

Just superb...

Well done.. Take care with that maiden.

Thread: Classic Aerobatic Model Photo Thread
01/05/2018 10:38:31

It has been rather quiet. My only contribution this year has been my Mama Mia. Seems to fly quite well despite its size..

finished4.jpg

Thread: Martyn's Dalotel
24/04/2018 15:25:37

Progress update.. I am spending rather a lot of time on this and don't seem to be getting very far. Working on two areas, the cowl and the undercarriage and then doing bits like adding cap strips while I have a few spare minutes.

There is only one accurate 3v that I can find and this does not appear to be too accurate(!) The cowl shape is wrong - it appears to be too narrow compared with the few photos I can find.

dalotel-3v.jpg

As I mentioned, the engine will be inverted. A quick test fit and the tank was still too high - so this has been lowered again. It will need a small cut-out in the wing to accommodate - that. I will need about 6mm removing from the upper wing centre section. Hey ho..

Anyway. The cowl. Basically built as per plan but taking care trying to get the shape right - especially around the rear curves or straights. I still haven't decided which is really correct.

cowl1.jpg

All still a bit rough - WIP

cowl2.jpg

The original was a Glass Fibre cowl and sat on top of the basic fuselage shape. the drop is intended. I'll glass the cowl in 18gm cloth - it will add a bit of resilience. I said it was still a bit rough...

cowl3.jpg

Surprisingly, the cylinder head doesn't protrude too far. The bottom part is (or will be removable) for access. The FS exhaust with exit at the rear opening. I'll need to get a new manifold for this. There is a vent from under the cowl at the rear which will be expanded. The inner side of the cowl will have a dummy radiator fitted both halves. This will be useful for deflecting the air to the cylinder head I hope.

The undercarriage has been fun as well. Using HK retracts, I am trying to replicate the some look as the prototype. I was originally intending on using oleos but the ones I bought were too big. However the stanchions were the correct size. Heat shrink represents the rubber gaiters.

wheels1.jpg

The leg is fastened to the retract unit using a stub of 4mm piano wire. To prevent it rotating in the stanchion, the leg was slotted (using a diamond cutting wheel on the Dremel) and pinned through using 16swg piano wire and then all slow epoxied into place. The little grub screws supplied stripped the aluminium thread the first time I tried to tighten them. You can see the pin holes if you look closely. Not much suspension but the tyres (are slightly oversize) but VERY soft. That is the springing.. I'll need to land this carefully.

wheels2.jpg

One challenge I have is to fabricate the doors so they open outwards at an angle when the undercarriage is lowered but close up and move upwards when the undercarriage is retracted. Its all about trigonometry. I just have to work out the angles and linkage lengths.

wheelwell.jpg

The wheel well bay has a 1/32 ply reinforcement ring on the inside

wheelwell2.jpg

The bay itself has been doped and sealed and a coat of fuel proof grey paint added. I am not adding any wheel well walls.

That's about if at the moment. The aileron fitting is the next airframe bit. Doing Trigonometry is the next thinking carefully bit.

 

More to come but this is slow. May get it finished by Christmas at this rate.

Martyn

Edited By Martyn K on 24/04/2018 15:26:14

Thread: Quarter Sawn Balsa
18/04/2018 15:45:24

A photo of what Quarter grain wood looks like..

p6230006.jpg

Both of the lower sheets (1/32 balsa) is quarter grain although the top half (in the photo) is cut towards the edge of the quarter area. The bottom part is beautiful and demonstrates exactly what you need to look for. The very long cross grain shows it was at 90 degrees to the growth rings in the tree. Quarter grain is not ideal for sheeting wings though as it is rather stiff and does not bend easily to the profile of the wing section.

Martyn

18/04/2018 15:06:41

1/4 grain has - as Peter noted - a speckled 'Mackerel Sky' appearance. The benefit is that its stiffer across the grain than normal straight grained wood and if decent quality you can go down a size in wood using light weight material

Mainly used for components that you want to keep warp free, like fins, rudder and wing ribs.

Decent wood is as rare as hens teeth. I have still got some that is 30 yo - keeping it for a special occasion. Probably use it to line my coffin laugh

Martyn

Thread: Peterf's 1/4 scale Falcon Models Tiger Moth
11/04/2018 11:30:06

That looks superb.. Absolutely wonderful

Thread: Peacemaker
11/04/2018 09:45:58

Is that the George Aldrich design from the early 60s Martin? Always thought is was a very nice Control Line model. Very elegant

Thread: Forum members' new models: Let's see them.
11/04/2018 09:38:27

Looks great Simon..

Thread: Swift 82
05/04/2018 13:06:26

Love that colour scheme CSB..

Great build blog as well

Thread: Taranis = Stopping a timer
05/04/2018 07:35:04

Sorry for the slow response and many thanks for the guidance. I spent a couple of evenings playing. I found it was much easier (as usual) to do this on the transmitter than using companion.

This was the solution I came up with. Its probably not the best but it works OK for a first attempt. I may not fully understand the concept of v1 and v2 but this works for me.

I used two Logical switches.

L2 first - I started work on L1 but realised I needed a second switch.

L2 is a>x Thr 0

For the uninitiated, this mean that L2 turns on when the throttle is greater than the midpoint . This allows a soft start before the timer starts

The difficult one was L1

L1 is Sticky (L2 (v1) and |SA^(v2)) AND SA^

Read this in two halves. Sticky means that once set it stays set.

So When L2 goes on, L1 goes on and stays on. However, I wanted to be able to stop the timer so the capital AND means that it also needs SA to be in the up position. Providing both were on then L1 would switch on. L1 would switch off when I moved SA from the top position. Great - I now had basically what I wanted. SA is effectively an arm switch and is also set to disable the throttle (set to -100) when not in the up position.

However, it was still possible to inadvertently restart the timer. There are two conditions (v1 and v2). The second |SA^ (NOT SA^) disables the L2 condition, preventing an inadvertent restart. Logically this meant that once L1 had turned off, the first condition needed both L2 on and SA being up to restart.

Back to the first menu screen. Now when selecting the switch to start the timers, both L1 and L2 have magically appeared in the list - select L1 and it works perfectly.

Thanks again. That was fun. I learnt a lot

Martyn

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