Member postings for Tim Rowe

Sensational!

Could watch that all day long.

Tim

+ for Pritt. When the time comes to take the paper patterns off, brush on some clean water and the paper will soak it up readily. It will also start to wrinkle and lift. If you keep going sparingly with the water the paper will more of less fall off taking most of the glue with it. If you try to peel the paper too early you will find more of the glue remaining on the job.
I do this all the time for balsa and plywood ribs and formers on model aircraft.
Just a light wipe with a damp (not wet) sponge or cloth and that removes any residue.
No nasty solvents!

Mick 70

Jason B has it on the nail. 4 laminations or 1.5 mm will give you a fraction over 6mm finish as there will be a slight growth in the glue lines.

Don't try to steam plywood as it will likely end in tears. In effect you are making your own.

You will need a reasonably robust former and loads of clamps which you could make with suitable lengths of planed pine and studs. The clamps will need to be very closely spaced to get even closing of the laminates and to help this I would have a sacrificial layer top and bottom which is not glued but simply there to provide a more even clamping pressure and to stop the job itself getting marked.

If I was doing this I would almost certainly use epoxy glues as the curing time can be made sufficiently slow to get everything lined up. It will also be durable.

You will get a bit of spring back over the length of your application but that does not look to critical. If it is, you will have to slightly overbend and there you are on your own!

Very helpful everyone but for the moment I have pushed the problem into the long grass.
Among my projects further down the list is a smaller motor glider with a smaller spinner. The collet was the same OD but drilled for the 3mm shaft. Overall it was a bit shorter needing a longer machine screw to retain the spinner cone but I have tried it and it works.

I am in a hurry to get this one finished but now I have time to set up to make a new one for the later model. Looks like it could become the perfect excuse to buy a few more tools.

Tim

Yes Mike

I totally agree an electric bill could be truly shocking! I could easily see me having the same argument as I insist that a toilet roll has the loose bit hanging from the front. Except that is if it is hanging from a wire holder old style on the back of the door in which case it has to come from the back.

As for the right word Neil I would just drop the 'e' and it now becomes "loctit" job done

Tim

Hi Bear
Now why didn't I think of that! Doh!
Tim

Hi Stewart

Many of the Cox engines are not fitted or equipped with silencers so they are noisy little beasts. I have got a Cox 010 and that is quite capable of annoying Spanish neighbours who are not generally known to be quiet peoples. My Cox 020 can annoy the neighbour's neighbours and as for the 049s and 051s well …………….. They are a big turn-off on noise sensitive flying sites.
The other problem is that most of them are not throttled so have reduced application in a radio controlled model. You can fit timer to control the length of the run and you don't need to fill the tank completely which can also give some control of the run time. To reduce the power you can richen the mixture so that they are 4 stroking and to get a significant reduction in thrust you can reverse the propeller.

Parts and new engines are available from Canada and there was quite a fun newsletter although that seems to have dried up.

I am lucky in that our flying field near Campos in Mallorca does not have noise limits or restriction and I have a number of gliders that could be fitted with Cox engines on pods to get them into thermals and soaring height.

My stronger interest is in IC engines especially four strokes but I also have a number of electric and I have to say that most of the kits and designs that I have built that were originally intended to be powered by Coxes I have adapted to use equivalent electric motors. With the small brushless motors available these days with lightweight and energy dense LiPo batteries a conversion often makes great sense. At the other end of the scale large models and top level aerobats can be electric as well and everything in between. Electric is also popular for twin and multi-engine aircraft.

I love the engineering in the IC engines and it is much harder to stir up similar emotions on an electric motor. One day maybe.

Tim

Thank you everyone for the quick and useful comments.

​Here are photos of the collet.





This second photo shows the collet in the backplate of the spinner. I should have described the arrangement a bit better. Overall it is a bit more complicated than my ability to make a new one although I like the idea. Perhaps I will have a practice some time but the slits might defeat me.

​For the moment I will avoid the Loctite and split a sleeve for all the good reasons given. I will check out what is available on eBay too.

​Again, many thanks

Tim

I am more a lurker on this forum but active on the sister model flying forum. The Proxxon PD 400 thread has been very interesting because I picked one up second-hand from Lancaster Model and Hobby World about two years ago with a job lot of associated tooling. It is noisy so I may have to look into that before I get stuck into any real project.

​Here is my question:
​I am just completing a 2m motorised glider and the out-runner motor has a 3mm shaft. The only spinner I could get hold of that matches the profile of the nose has a 5mm aluminium taper collet so I have to make an adaptor. The model shop where I bought the items suggested a piece of brass tube that would make up the gap with a longitudinal slit so it would be clamped to the shaft by the action of the collet. The standard sized brass tube that was suggested however was sloppy on the motor shaft and instinctively I don't like this idea. This is happening in Spain but I do speak Spanish and understood the advice.

​I have a suitable piece of Dural that I could make a sleeve from and a 3mm reamer so the adaptor could be a close fit over the shaft. My inclination is to Loctite the sleeve to the shaft so it is a permanent feature converting the shaft to 5mm and then using the collet on the spinner as intended. If I go this route what Loctite should I use.
​The alternative would be to make the adaptor sleeve exactly as before but put a longitudinal slit so it would clamp on the shaft more in line with the model shop advice.

​It is not a big powerful motor being only 280W driving a 7" folding propeller but nonetheless it would be embarrassing if it came off and the rearward shift in cg would probably by fatal to the aircraft.

What is the better option?

Tim

Mark
​Size of a single bed! That's one big model but even so scaling down a realistic engine sound will be tricky I think. You already said that the most important thing is the sound so why don't you start there. As other have suggested using a sound module can give you exactly what you want. You could start be sampling the real thing at your local harbour including backfires, rattles, whines and whatever else makes it authentic. Assuming you are going to fit radio control (although at that size small people might do) you can link the sound to the throttle and even include a start up. There are various software programs (musicians use them) to change the tempo of music without altering the pitch. If you really want to you could have a separate channel to make a seagull sounds, and to go the whole hog, the skipper giving instructions to the wooden crew using whatever choice language you can get away with. That's your sound sorted.
​With electric propulsion you could use a low kv brushless motor in which case the battery can go anywhere and can be useful ballast as it des not change weight as it runs down. If you want to swing a scale propeller you may still need a reduction gearbox.
​That's two things sorted out but now you can make a dummy Bernard engine which I have looked up and is mostly hidden with casings. But anyway you could create all the scale detail you want or go for an equally authentic engine like a Baudouin semi diesel that seems like it only fires on alternate days of the week.
​You can choose the size instead of being driven by something that will need craning out of your workshop and you can make the whole thing as easy or as complicated as you like.
Let us know what you decide and if it saves your marriage!
Tim

I have been lurking for long enough and really enjoying this forum as well as modelflying where I have been contributing.
​My grandfather was the real modeller in the family and he put some impressive things together that as a youngster I enjoyed taking apart. Fine up to a point but I always managed to lose at least one piece.
​Many of his books and Model Engineer magazines were passed on to me and the intrigue has grown to the point where I now have to do something about it.
​A model that did survive my dismantling reasonably well was a 2 1/2 " loco that I think is a Dyak. It is 2--6-0 and I would like to restore it some time. It doesn't need to steam again but in other respects I would like to do a proper job. First I need to learn on some other things and this site is surely the best place to be.
​60+ years have come and gone and at long last I now have my own little workshop with the main machine being a Proxxon 400 lathe with milling attachment plus a pretty good collection of hand tools.
​I have a technical and engineering background but with big gaps!

John - Not really. Chris has it where the punch rotates at an angle to the vertical. The best analogy I can think of is a spinning top where the point stays in one place but the main body orbits creating the angle. The beauty of the system is that no heavy presses are necessary. We used standard drill presses.

​This was in a production environment with many thousand operations per day. In a home workshop I would probably take the Loctite option or even very thin super-glue applied after a very light peen.

Chris
​The process for fixing is called rotary riveting. Google it to see how it works. Basically it combines spinning with pressure. We used to make a range of stainless steel yacht fittings where spacers or small shafts were fixed to side plates. The action which is akin to a wobble keeps the material moving and prevents cracking due to work hardening. It is extremely quick and the geometry of the parts is very simple.
​The tool is a bit more complicate but if you have a standard size boss you only need one set of dies.