Author Topic: Flights of Fancy (Read 87616 times)

TheLurker · « **Reply #275 on:** 16 September, 2020, 09:09:09 pm »

ElyDave · « **Reply #276 on:** 16 September, 2020, 09:16:12 pm »

I'm going slow due to masses of work keeping me brain dead in the evenings, but with the dansing programme on the beeb restarting, I predict an uptick in balsa fettling.

Fuselage structure mostly done, with front and rear stringers. Managed to get out of sequence and fit bottom stringers ahead of the undercarriage and F5A, but I can get them in with a bit of fiddling. U/C bending went surprisingly well, will post a pic sometime. Only made one error, tried to unbend it and snapped the wire. Good learning curve, remaining wire was sufficient and I paid attention. Just need to trim the legs for the wheel fit.

TheLurker · « **Reply #277 on:** 17 September, 2020, 05:45:21 am »

ElyDave >I'm going slow due to masses of work keeping me brain dead in the evenings...

Likewise and the brain fog lead me to screw up the bottom line of the anti-glare panel which means it's wrong for 62620, but I'm consoling myself that there are examples out there which do have it as I've done it. Just not 62620, grrrr.

ElyDave>... but with the dansing programme on the beeb restarting...

Lovely isn't it? Two (or more) hours guaranteed to be absolutely free of interruption every Sat. for far more important things.

ElyDave> Just need to trim the legs for the wheel fit.

Don't do that until after you've fitted the wheels. If you use an insulation sleeve to hold the wheel in place it's far easier to leave the UC leg overlong, fit the wheel, slide a longish sleeve into place, cut to length and then a put tiny dod of glue (epoxy, CA) on the cut end. Make sure the sleeve _is_ glued in place or you may find yourself having to make another wheel (or wheels) to replace any that get lost on landing in long grass. Yes, that is the voice of (bitter) experience.

If you've yet to sand the wheels to profile it's worth knowing that the x-sect shown on the plan leaves you with quite a "square" looking wheel. The tyres on the L-19/O-1 were chunky, but not _that_ chunky so a bit more of a curve than shown is required. It's not obvious it's "wrong" until after you've painted the wheels. DAHIKT.

TheLurker · « **Reply #278 on:** 20 September, 2020, 05:34:20 pm »

Sorry, but ICBA to log in to imgbb & upload pics. Moar Bird Dog WIP

TheLurker · « **Reply #279 on:** 25 September, 2020, 10:06:10 pm »

Done all but five minutes of titivating. A little bit of paint on the underside of the nose and some matt Al. on the insulation sleeves holding the wheels on.

At least one glaring error in the decoration, *shrugs*. Combination of tiredness and stupidity. And, as is traditional for me, I have finished it just as the weather turns foul for the foreseeable.

Weight sans rubber 28.91g
with 32.66
So throw in a motor peg and it'll be 33g for everyday.

andytheflyer · « **Reply #280 on:** 26 September, 2020, 04:10:26 pm »

That's very nice TL. I'd be proud of that. Hope you get the right weather for a maiden shortly.

TheLurker · « **Reply #281 on:** 27 September, 2020, 09:41:08 am »

Quote from: andytheflyer

That's very nice TL. I'd be proud of that. Hope you get the right weather for a maiden shortly.

Ta. Tomorrow and Tuesday are looking promising at the moment and the grass on the "aerodrome" is a good 6" to 8" long now

TheLurker · « **Reply #282 on:** 29 September, 2020, 09:15:16 pm »

Bird Dog. Got the glide sorted out, but power trials were not great. Even on only 100 or so turns (about 1/8 of "safe" maximum) using the kit rubber (2 strands of 3/16") getting a stall. Come the next calm am going to try with a spare 4 strand 3/32" motor. Only had about half an hour this evening before testing curtailed by poor light & the dew setting in.

Quote from: Morat on 12 March, 2018, 07:33:57 am

Thanks for the info! I hope WW comes back with their full range.

This may already be well known, but I didn't know until yesterday that VMC have taken on West Wings' range of products.

This month's BMFA News, p49. It's a throwaway comment in an, interesting, article about VMC's Balsa Basics RC Spitfire.

ElyDave · « **Reply #283 on:** 29 September, 2020, 09:23:11 pm »

Slow and steady progress in the flatlands.

- Air intake lamination completed
- Nose block sanded to profile - a curious mix of art and engineering. Will take another look after putting it aside for a day or so, just to make sure I'm happy with it
- U/C wires fitted, tail wheel fitted
- Front of fuselage planked
- wheels sanded to shape

Will post photos eventually.

TheLurker · « **Reply #284 on:** 05 October, 2020, 10:05:20 pm »

If your stocks of balsa are running low *now* would be a *very* good time to restock. We're in for steep price rises, as much as twice current, quite possibly with low availability thrown in. Seems the wind turbine industry is hoovering up vast quantities of balsa for blade cores.

TheLurker · « **Reply #285 on:** 17 October, 2020, 06:03:05 pm »

Bit more repair work, this time in the Chiribiri No. 5. Have to say I was quite expecting this, the combination of bamboo & basswood in v. thin sections did seem a bit... delicate. Should be a straight-forward repair, the trick will be working out how to improve strength without adding undue weight. At the moment I'm thinking of either cyano impregnated paper strapping or v. fine wire or thread bindings.

However the Bird Dog is now part trimmed, up to 300 turns which is good for a circuit and a bit. On which subject; Dave, the 3/16 kit rubber proved too beefy for mine. More than 100 turns saw almost instant stall from hand launch. I'm currently using a 4 strand 3/32" motor. As far as nose weight goes mine need a big old lump, but my kit wood was pretty heavy and I've got the hinged rudder so perhaps to be expected. There were a couple of other Bird Dogs at today's meet and there was quite a variation in nose weight from about the same as mine to perhaps 1/4 of what I'm using. Mine also needs a 1/16" shim for downthrust and about 1/32" right thrust on top of the 2 degrees I built in. As I managed to bend the prop. shaft - nasty stall into hard floor - I'm going to reseat the nose button to build this in. Not sure when I'll be able to continue trimming it, but will post an update when I do to try and give you a head start on it.

ElyDave · « **Reply #286 on:** 17 October, 2020, 08:19:34 pm »

Total thread bomb with photos

Construction progress on Bird Dog, plus repair on Veron glider - a bit scrappy, but that v-section is difficult to get the tension.

U/C - managed to snap the wire once, but had enough to get it right second time. Hopefully have enough for the struts inside the canopy as well.

Fuselage and wings

And the glider

And a top tip for weighting - if you are a single malt drinker (reasonable guess?) or have the occaisional good bottle of wine, the lead foil capsules aare great nose weights, easy to fold flat, cut, stick to things etc.

Today - painted nose block Tamiya Flat Green, wheels and anti glare panel Humbrol Matt Black. Pored over the instructions for the various cut-out sections prior to starting coverage and assembly

andytheflyer · « **Reply #287 on:** 17 October, 2020, 08:53:13 pm »

That's looking very nice, well done. Are you TL in disguise?

TheLurker · « **Reply #288 on:** 17 October, 2020, 09:08:27 pm »

Quote from: andytheflyer

That's looking very nice, well done.

Andy beat me to the punch. He's right, the BD is looking good and the wing repair looks absolutely fine. FWIW I find that repaired models get more flights in than pristine, off the bench ones because, like that first scratch on a brand new bike, you become a little less precious about it.

> ... if you are a single malt drinker (reasonable guess?) ...
As it happens I am, but I only get through a couple or three bottles a year so that's not the most convenient source of ballasting... however ... I do have a couple of large offcuts of roofing lead that can be hammered, cut and or smelted* into convenient shapes.

> ...thread bomb...
You can never have too many pictures of aeroplanes. Toy or otherwise.

*H&S? Wossat then?

ElyDave · « **Reply #289 on:** 17 October, 2020, 09:20:23 pm »

H&S - that's for the workplace. I have lost count of the times Mrs ED has retorted "call yourself an H&S man?"

In my defence, it's been a while since I've attended minor injuries.

andytheflyer · « **Reply #290 on:** 18 October, 2020, 08:43:25 am »

Ah!Is this a common factor - model aeroplane building and malt whisky?

I'm an Islands man, particularly Islay. Comes from geology field trips as a student to the Hebrides and the Scottish NW Foreland. These rocks are not part of the UK y'know.

Malt - as seaweedy, smoky and peaty as possible please. Laphroaig, Ardbeg, Port Charlotte. None of those smooth, refined Highland potions. Need to be just like me. Rough and ready, uncultured.

And Grouse for everyday. Well, not everyday, but you know what I mean.

TheLurker · « **Reply #291 on:** 24 October, 2020, 09:59:47 pm »

Quote from: ElyDave

In my defence, it's been a while since I've attended minor injuries.

Umm, about 2 years for me I think. Cutting strip (and a finger) for the Walthew MKII.

Quote from: AndyTheFlyer

Malt - as seaweedy, smoky and peaty as possible please. Laphroaig, Ardbeg, Port Charlotte. None of those smooth, refined Highland potions.

I will drink them if offered, it's only polite after all and one wouldn't want to offend one's host, but my taste is for the refined* Highland potions.

Fettling the Bird Dog after last week's trimming session.

Repairing the chipped air inlet. Dave you might want to think about case-hardening the air inlet with a smear of cyano, that fine edge is quite vulnerable. Yes, the NB did get re-painted.

Increasing the built in right & down thrust, now 2.5deg & 3deg. Right is more or less there, may need a tad more down.

Move *most* of the ballast inside. Epoxied to the back of bulkhead 1. At the moment up to 6g and likely to need more, that's what comes of not so great kit wood. All the ballast will end up inside when it's trimmed out, but easier to add than take away.

*Oh dearie me, the voices of the Morningside Ladies in the cafe at Jenners.

ElyDave · « **Reply #292 on:** 27 October, 2020, 10:50:27 am »

Warp Speed Ahead

Oh dear, covered the tailplane and fin, following the instructions I shrank both sides of the tissue simultaneously (which I don't recall doing with the glider), and either because of that, or insufficient holding down, I have a wavy, wobbly horizontal tailplane.

What's the solution? Reshrink side by side with sufficient weight on top, or remove tissue and recover?
Or is it a result of a light construction and me trying to get the tissue too taut pre-shrinking?

TheLurker · « **Reply #293 on:** 27 October, 2020, 11:51:02 am »

Ah. Million and one possibilities.

I'd strip it off, steam it for a good long time while bending it *gently* against the warp (don't burn* yourself) then pin it down for at least 24 hours. Let it sit for a few hours after you unpin it, to see if takes up the warp again. If it does, repeat.

Definitely shrink the tissue on both sides at the same time, simple 1/16" sheet outlines don't have much warp resistance.

If it absolutely refuses to flatten after two or three goes use the existing parts as a template and cut new from the sheet scrap in the kit. Another possibility is a laminated outline, which will have a better strength to weight ratio and is likely to be lighter than the sheet version, but we can leave that for another day.

I have been known to pre-shrink tissue before applying it to flat, lightweight frameworks. Take something like an old picture frame, it needs to be *very* rigid, tape the tissue to that, mist or steam shrink it. Use the ready shrunk tissue to cover the framework, with as few wrinkles as possible, before doping it. It'll shrink a bit more if your "dope" is a shrinking dope, but not too aggressively, taking up any small wrinkles.

*Easier said than done.

TheLurker · « **Reply #294 on:** 27 October, 2020, 05:33:17 pm »

A thought.

Rather than using weights, which can shift, when you dope the tail. Pin it down. If your LMS has t-pins buy a packet of those, grab a hole punch and a something like a Total yoghurt pot lid - needs to be reasonably robust - and punch out lots of little discs. Stick a pin through the centre of each little disc.

Rest the stab. on some spacers placing lots of pins around the perimeter. Slide the discs down so that they hold the piece down firmly. See the pic. below - they're being used to hold down some laminations for a rudder TE rather than a doped item, but you get the idea.

If you can't get t-pins easily Dunelm sell some long & relatively thick glass headed pins fairly cheaply which would do as well.

ElyDave · « **Reply #295 on:** 02 November, 2020, 08:53:26 am »

Steamed the tailplane with the iron (in a pressing cloth) at the same time as smoothing the tissue, looks like it might be OK.

Wings covered over the weekend, one of them shrunk with no warps and the other drying now. A little more structure in the wings to resist the warping. I foresee a lot of fiddliness getting all these paper templates cut and fitted, need to read the instructions fairly thoroughly before embarking on a spree of stuff. Good job I didn't throw all my OHP pens for acetates out, window templates marked up ready to go.

TheLurker · « **Reply #296 on:** 02 November, 2020, 09:34:59 am »

Quote from: ElyDave

Steamed the tailplane with the iron (in a pressing cloth) ...

Now that, that is a bloody good idea. Nicked.

Quote from: ElyDave

I foresee a lot of fiddliness getting all these paper templates cut and fitted...

Err. Yes.

The paper templates are highly unlikely to need any adjustment but holding the cut acetate in place will make you wish you were double-jointed and had a third hand. The rear canopy isn't too bad, but the front and side glazing is a bit of a.... fiddle.

I expect you've already worked it out, but in case you haven't, small bits of masking tape can be used to hold the main glazing in place until you've glued it. The trick with cyano and acetate is to "spot weld" it rather than trying for a seam joint. CA fogs acetate quicker than you can say, "Jack Robinson".

Bon chance.

Ermm. Want some more free, probably unnecessary, advice? When cutting the acetate, tape it down to the cutting board and then tape the template to the acetate and use a fresh blade. Makes all the difference for the tight curves and notches.

ElyDave · « **Reply #297 on:** 02 November, 2020, 08:53:37 pm »

Still about half a mm out of true, think I'll give it another steaming.

Wings are looking OK though

Did you trace the patterns onto paper to place over the acetate? I pinned it to the board over the plan and traced it with the OHP Pen

TheLurker · « **Reply #298 on:** 02 November, 2020, 09:24:21 pm »

Quote from: ElyDave

Did you trace the patterns onto paper to place over the acetate?

I have done in the past, good old grease-proof paper to the rescue. However this is, "The Modern World" - oops, sorry, wrong thread - and you can download the templates as A4 sheets from VMC.

Go here,

https://www.vintagemodelcompany.com/cessna-bird-dog.html

open the "Additional Resources" section and the templates are available as downloadable PDFs.

*Cave* There are some very important guidelines missing from the downloadable tissue template sheet. Compare closely with those printed on the plan. I missed this vital step.

ElyDave · « **Reply #299 on:** 04 November, 2020, 08:23:53 am »

Cheers, will go and check, particularly to remember which of those are directly cut from the paper vs which might need to be transferred to something else, and which need to be done as LH and RH parts.