Flair Puppeteer

[Alan Hilton]

A second to Jon’s comment re c of g the mk 1 kit marked position was too far back .I have no experience with mk 2 kits .Regarding closed loop I used Mick Reeves Kevlar thread on my last build and found it better than the metal fishing trace I had used for years

Alan

[John Bisset]

Like you, barryt, I am dithering about the front end. Don Fry's hinged cowl area sounds interesting - I haven't heard of that before. Maybe a scrap trial build is needed!

[barryt]

Hi all. Sorry about the delay in responding. Domestic issues getting in the way of my chosen hobby again. Using the ‘self isolation’ excuse at the moment!

Taking a good look at the fuselage to see how a closed loop arrangement would work. I know it would look great and I would really like to pursue this solution. No issue with the rudder and I have done that before on other models. I am struggling with the elevator arrangement though.

I traced the fuselage top and side view then added the ‘more or less’ scale positions, and angles, of the elevator control cables. It appears that the vertical mounted elevator servo ends up significantly aft of the CG. Not only that, the servo would end up in an inaccessible position.

I guess one solution would be to mount a vertical swivel bar at the position where the elevator control cables converge and then drive that bar, using a pushrod, from a vertical servo mounted further forward. This will add complexity and make it awkward to attach, and tension, the control cables.

Before I go any further, is this the way it should be done? Does anyone have a simpler solution?

John, check this video for the removable front end. **LINK**

I think I will use a similar mounting method but I will have to place the battery in the fuselage instead of the cowl.

Looking forward to your responses.

[John Bisset]

Good grief I can't believe it is three months since this was posted. I did get distracted by 'domestic issues' as part of this virus problem , but I hadn't realised it was that long. Sorry about the long delay!

Thank you for the video link barryt - I now have a part built fuselage which aims to have a similar system. I rather like the idea of an interchangeable 'power pod' for different machines, though I suspect the theory of that sounds better than the practice will be.

On your elevator cables question, I suspect this is far too late now, but have you thought of simply running the cables through small diameter cooper tubing acting as a sleeve into the fuselage, each side. The copper tube bent in a gentle S shape to bring the control wires into a position ~ parallel to lead to the servo? I did something like that in a smaller model years ago. It worked well, since the movement is not great and I saw little wear in a couple of years (light) flying. I used Laystrate control line wires and 1/16" copper tube as I recall. I had debated about putting the smallest size of heat shrink tubing over the wires at the fuselage entry as a wear reducer, but didn't bother in the end. Not sure if thta is of any help - I may have misunderstood your drawing.

Meantime the other problem I have been debating is wheels, though I have some time on that yet. Currently no commercial wheels of the correct size seem to be available in the UK, and I came back onto the forums just hours too late to spot the Williams Brothers wheels that were offered a day or two ago. Rats! I shall put out a 'wanted' add soon.

So - does anyone have any suggestions on building my own? I think I may manage to cast some tyres eventually - I have done some silicone rubber casting before and I suspect the softer rubbers used for that may be about right. Not sure though...

John B

[J D 8]

Hi John, rubber O rings are available in a wide variety of sizes and cross sections. They are widely used in industry. Simply bearings are just one source.

Cheers, john.

[Dave Cunnington]

There are other threads on the wheel subject, sorry I don't know where but it's worth a search.

My son produced some 3d printed wheels for me and I stuck 10mm neoprene onto them as tyres

Don't knock the lack of scale details, I'm just enjoying the rebuild of a very old airframe and

hopefully one day I'll get it to fly !             SC 52 2 stroke, home made cowl

 

Edited By Dave Cunnington on 30/06/2020 14:07:48

Edited By Dave Cunnington on 30/06/2020 14:12:18

[Geoff S]

My method for feeding closed loop wires through the fuselage is to use snake inner as conduits but make sure your choice of wire will pass through the small hole first. I've used it on both my 58" DB Moths (Tiger and Cirrus/Gypsy) successfully and on my unfinished 60" Pup. It makes feeding the wires through completely hassle-free for all 3 (rudder and both elevator halves).

Geoff

PS of course the rudder closed loop on the Moths is outside the fuselage but all 3 of the ones for the Pup are fed with snake inner.

Edited By Geoff S on 30/06/2020 14:17:11

[John Bisset]

Thanks jd8 and Dave C - I have some fairly large size O-rings,but shall investigate that link. Likely to work better than my musings on joining some suitably sized tubing together - though carefully cut neoprene is a thought Dave.

Geoff s - that sounds like a lower drag option than mine!

[Geoff S]

Here's what I mean by using snake inners as closed loop conduits:

It's easy to thread the wires in from the outside and, perhaps just as important, easy to replace them if there's a problem.

Geoff

[John Bisset]

Thanks Geoff - an idea I may well use. That ease of replacement can be important.

 

Edited By John Bisset on 30/06/2020 20:39:24