Topic: SE5 restoration

Giles,

I'm with greyhead on this one.

From my trusty Zeus book, 10 swg is 0.128" or 3.2512mm

Alan B

Regarding getting as high an rpm as possible, I don't think you need to get concerned, I've got a Laser 200 in a DB 1/4 scale SE5 and there's ample power. Take offs and climb out at what I judge to be in a scale fashion takes about 1/2 throttle. On full throttle it will go up at about 30 degrees - most unscale like! Just get the engine to run, erring slightly on the rich side, and you'll be rewarded with a cool yet powerful enough performance

Hello all,

I am still without my camera so I've made up a very quick 3d version of my exhaust design. The basic idea is for the silicone pipes to run through the dummy litho headers completely and then into a long aluminium pipe for the exhaust itself. The silicone pipes are the ones I have already trialled and achieved 100rpm increase in top speed. They have an internal diameter of 9mm, the same as the Laser exhausts. The aluminium tubes I have found are 7/8 in outer diameter (about 22mm) and 18 swg, which is 1.2mm thickness. I get 2.4m for about a tenner.  This diameter is the right scale for the models scale exhaust.

Now, the increase in internal diameter - ie from 9mm in the silicone to approx 19.6mm of the aluminium tube should help to not increase the back pressure too greatly. In other words, if I simply used a 9mm internal pipe then I expect I wouldn't be able to achieve such a long exhaust as I'm hoping to with this aluminium tube. I need to make a join between the silicone and the aluminium that is gas tight, I'm hoping to find some kind of rubber O ring for this.










I have set up a quick rough and ready version of these pipes and I'm hoping to test it at the weekend. I'm using plastic electrical conduit that is conveniently the same size as the aluminium tubes.

What do people think?

I have to say that I’m very impressed with your graphics and the principle seems perfectly feasible.  Being a fair distance from the actual exhaust I wouldn’t be surprised if the plastic conduit does the job so negating the need to buy the aluminium tube; it would certainly be easier to produce the tuned out end with the plastic.  Silicone sealant as used in bathrooms etc. would make a reasonable seal between the two pipes and once again I don’t think there would be enough heat to adversely affect it.

I do 3d graphics for a living. If you liked that you'll love this:



Stills from an animation of the Ford GT. Nothing there exists, it is all 3d.

I'm glad you think that the idea is sound Grahame. I liked the idea of the aluminium as it has a bigger internal diameter, is probably lighter and I get very slightly dent and distress it to get a bit of detail. Although you are quite right about making the turned out end.

I have run the Laser engine with mock up exhausts running down quite a length of the fuselage, to a scale length.

<a href="http://www.youtube.com/watch?v=HVKGzQPt4Kc" target="_blank">http://www.youtube.com/watch?v=HVKGzQPt4Kc</a>

The sound of the engine has improved, if such a thing were possible, and the revs I can get at full throttle have increased! I was getting 7,700-7,800 rpm, with the long pipes I'm getting 7,800 - 7,900. This could of course be as the engine is still running in, but the main thing is that the engine is not being restricted in an adverse way. As you can see in the clip I rev the engine up is a most un-scale like manner, which I was please about as I was expecting the increase in back pressure to prevent this.

So, I shall now be starting to manufacture a nice scale looking set of heads and exhaust manifold to go around the silicone pipe and aluminium tubes that will make up the long pipes. The plastic pipes shown here started to melt!

I am delighted that this has worked out. I will now only get the gunk from the exhausts over half the model.

I am also thinking of making up a small tank under the engine with a short length of pipe feeding into it from the crank case breather as this gunk is currently free to drip out of the bottom of the engine bay. This would help with keeping the model clean too.

Very, very nice Giles,

OK you've convinced me.  Perhaps I should look to a Laser for my Storch.  I've become a big fan of petrol engines but I haven't really found one to fit and your Laser does sound good.

Alan B

Having established that this will work I'm having difficulty getting hold of some aluminium tube. I can find 3/4 inch outer diameter tube with an 18swg wall, but I need to buy 50 quids worth, I need about 2 meters!

Can anyone suggest an alernative tube? The plastic I had was going to melt.

folding deckchairs?  I'd offer you the one in the back of my car, but then I'd have nothing to sit on between flights!  I'm pretty sure the frame on that is about 3/4 dia, or do you have a non-ferrous scrap merchant near you?

Now that is an excellent idea - I've had a google for some scrappies and there are some close by so I'll do some phoning around. Thanks

Hello all,

I am getting my DB models 1/4 scale SE5 ready for the summer. It has been dormant since last year.

My first job is the tail skid. I have had endless problems with the skid as so much force gets put through it when landing and taxiing, and it was always breaking. One option is to fix the skid so it is not steerable, as the problem is the strength of the hinge.

I'm wondering what kind of problems I'd have if the skid was fixed and the only steering on the ground was via the rudder.

Giles

One of the other issues I wanted to ask opinions on was fuel for my Laser 200V. I had been running it on the Model Technics Laser Mix. I had some running problems in that the midrange running was lumpy and nowhere near as smooth as the engine was when it was new (it has only had about 20 flights). One suggestion was that because the engine was now run in the mixtures needed to be adjusted - this lead to endless fiddling and no good results.

One of the cylinders was producing a much blacker exhaust gunge than the other side. You would assume this was the mixture, and that it was running too rich - but again, I'd fiddled with the mixtures (both top and bottom end) with no improvement.

Neil at Laser suggested trying a 5% fuel, which so far I have been reluctant to do as I'm worried that the engine will start to corrode internally.

What would people think about using 5% fuel?

I wouldn't be too worried Giles, particularly not if Neil Tidey suggested it. Of course some might argue that nitro isn't the problem anyway, it methanol. As you may be aware methanol absorbs moisture from the air. Unfortunately you can't run your Laser without it.

I run all my Lasers including my v twin on Southern Modelcraft Laser mix Giles. Its about 2/3rds the price of the MT stuff, and I've never had a problem with it in almost 20 years.

Giles,
      I run my Laser 240 V Twin on 10% Prosynth - as recommended by Mr Tidey himself. The 240 likes 10% Nitro .

      It's the only fuel I use on all my engines. No problems with corrosion as Prosynth uses Aerosynth oil as the lubricant.

     Now Aerosynth is just about the best oil for preventing corrosion. All I do is run the engine dry , at full throttle , at the end of the days flying. Then just put it away - no after run oil needed.

     My 240 is now coming up to 6 years old and is as clean, inside and out , as the day it was bought.

     Everybody has their own particular brew , this just works for me.


              Great engines aren't they ?

I wouldn't be too worried Giles, particularly not if Neil Tidey suggested it. Of course some might argue that nitro isn't the problem anyway, it methanol. As you may be aware methanol absorbs moisture from the air. Unfortunately you can't run your Laser without it.

I run all my Lasers including my v twin on Southern Modelcraft Laser mix Giles. Its about 2/3rds the price of the MT stuff, and I've never had a problem with it in almost 20 years.

Ditto;good fuel;good price and good service from Dave watts.

Hello all,

I have adjusted my roundels - this is what they looked like before:



And this is what they look like now, much better. I had calculated the size of the red section wrong!



Interesting how the blue hue is different. The before picture was about a year ago, and the camera exposure is different too.

I am adding some of the markings that were missing for the first flights last year, things like the number on the tail and the big K on the top wing. I also have a selection of scale parts I've been making up for around the engine.

Thanks for the advice on the fuel. I have some 5% knocking about somewhere, so I'll give that a go next time. I also have quite a bit of Laser Mix - I wonder if I could mix that with some 10% in order to get through it?

Giles,
      Try not to use a fuel with any , or very little castor oil in it. Laser's are much happier on a mainly synthetic brew.

I have adjusted my roundels

Amazing what a difference the proportions make Giles.   Looking even better than it did before

Alan   

I have made good progress on my new tailskid design. All the previous attempts at this have failed. There is just so much force being applied to the skid that the hinges have failed - or the hinge has survived and ripped itself out of the wood it was mounted on!





One one side this is soft balsa, on the other side it is a sheet of 4mm ply with Kevlar cloth applied for strength. Inserted into the end of this sandwich is a mild steel plate with a steel hinge MIG welded to it. The idea is that the load is now spread up the length of the skid - and the hinge will not be able to come off!

Bellow is the tailskid I'll be using first, the green part is being reused, and the bolts there are likely to pull out of the balsa/ply sandwich that makes up the skid itself. When this happens I have made up another version - pictured below - with some spring steel welded to the other side of the hinge, this will stick out of the bottom of the wooden part of the skid itself and help absorb the forces involved.

I'm very pleased with my progress on the SE5. Many months ago I made the decision to get a 200V Laser for this model. Shortly after that I was able to plan to have working scale exhausts on the model. There then followed an extended period of fitting the engine and then developing a home made exhaust that would fit within the scale dummy exhausts. All this took ages and was very frustrating, but last year I was able to fly the model with the home made exhausts. What I didn't do was to make the dummy engine, now I have:







The rocker covers are ply base with lithoplate cover, painted with a nice high gloss black. I know that the real SE5 would have a dull finish, but I was so pleased with these rocker covers that I wanted to show them off a little - hence the shiny finish.

Under the rocker cover is a simple ply and bala engine block. The exhaust headers are tin plate (golden syrup tin!) soldered together with the tops of the tubes heated in a gas flame to give a nice blueing.




One of these tin tubes covers the actual exhaust pipe from the Laser, one covers a structural wire, the other two are empty. The positioning of these pipes in a 1-2-1 pattern is also scale correct.




The two halves of the exhaust itself are litho plate moulded in a female mould. I was pushing the limits of the litho at the front curve, and they have all split here. However, as everything is still to be painted I shall be able to disguise this. I'm thinking of using some heat resistant paint I have used in the past for real engines - the actual exhaust which is hidden in these will certainly get hot enough to affect the paint.

There is a concern that the heat will be sufficient to melt the litho - but it will have a steady stream of air running over it so I'm keeping my fingers crossed.

I was looking back through this build of mine and realised that I hadn't posted the link to the YouTube of the SE5 flying last year. Here it is:

<a href="http://www.youtube.com/watch?v=P9mHkJoOEvk" target="_blank">http://www.youtube.com/watch?v=P9mHkJoOEvk</a>

This was with the home made exhausts - but no dummy engine. I flew it quite a few times like this to prove if things were working OK. I have now repainted my roundels with the correct ratio of circles too.

I'm working on adding all the scale details that are missing from the model. My current task is the manufacture of the two radiators at the front of the fuelage, or more accurately, the slatted Venetian blind type structure in front of the radiators that would control the cooling.

I am planning on using tin sheet to form the outer rectangular shapes, and then run thin metal tubes between them with tiny tin slats soldered to them to make up the adjustable slats.



My question is should I use a brass tube to make the horizontal bars? I need a metal that I can solder to the tin rectangular outer structure. I can't find any tin tubes or bars, but there are plenty of brass ones. I presume I can solder tin to brass?

The other issue is one of actually cooling the engine. At the moment I have a baffle in front of the V-Twin to ensure all air passes through its fins, you can see this in the YouTube videos in the previous post. The only thing going in front of this baffle will be these radiator slatted structures. I'm not sure if the addition of the slats will create enough turbulence to limit the amount of cooling air getting to the engine. It could be that the slats, when assembled in the fully open position will actually provide a streamlining effect and help the cooling!

You can solder tin to brass or copper, mild steel or stainless steel but I doubt you have pure tin, rather tin plated steel.

I'm using the KS metals tin sheet - surely this is just tin and not plated?

In order to solder to stainless or mild steel don't I need to use silver solder? I'm hoping to get away with electricians solder as I find silver soldering a complete pain!

Mild steel is easy to solder I use LA CO flux which is a paste, tin everything well 1st.  S/S can be difficult to solder but again tinning is the key. tin is about twice the price of copper, to my knowledge it's rare to have pure tin plate as it's quite soft, like pewter I believe.  Mild steel etc is tin plated to reduce corrosion and makes it easier to solder.

I'm using the KS metals tin sheet - surely this is just tin and not plated?

In order to solder to stainless or mild steel don't I need to use silver solder? I'm hoping to get away with electricians solder as I find silver soldering a complete pain!

Giles - all the 'tin' sheet I bought from KS (but it was 20 years or so ago) was actually tinplate. Easy way to check - scratch it.
Mike

Giles - all the 'tin' sheet I bought from KS (but it was 20 years or so ago) was actually tinplate. Easy way to check - scratch it.

Or, get a magnet .........

Alan B

Or, get a magnet .........

Alan B

Better still - I didn't think of that!
Mike

Does anyone know where I can get a quarter scale Lewis gun?

Make one from brass or ali tube, lite ply etc 

Pegasus Models in Norwich have BUSA 1/4 Lewis guns in stock at £16 each.

You can buy a lot of balsa and ply for £16 

I'd like the idea of making one. I've got some scale drawings and it looks fairly straightforward.

These are some pics from another SE5 enthusiasts build:





So I might have a crack at doing it this way. I'll probably do a 3d model on the computer first to help me work out how to put it together. Then I can print out the parts I need to cut out and stick paper cut outs on the ply.

I like the 3d idea, could put it on here as a sticky 

You can buy a lot of balsa and ply for £16 

You can indeed, but that was not the question 

If you are thinking of building one the specs may help for scale:

Specifications
Weight    28 pounds (13 kg) (not really relevant )
Length    50.5 inches (1,280 mm)
Barrel length    26.5 inches (670 mm)
Width    4.5 inches (110 mm)

I'd like to paint my prop so it looks wooden. I use a black plastic one, so I'm thinking I can rub the surface down a little so it will take the paint, but I'm at a loss as to how to get a wooden finish.

Can anyone offer any advice?

You could try 1st painting with white or cream paint then go over the top when dry with stain varnish using a coarse brush, quick rub down then over the top with a better quality brush and very thin stain varnish.

I did this very roughly on my Pups rear fuselage deck and I mean very quick job but at a glance it's convincing.