Cloud Models Mosquito for PSS

[Steve McLaren]

Well, since I came back from the last event at the Great Orme with all my proper models pretty much in-tact (there was also that bag full of polystyrene!, but we won't talk about that!) and the mass build A4 is not going to be available till February, I really need something to keep me busy during these wet and windy weekends.

Well fortunately, at the Wings and Wheels show at North Weald in July, I bought myself a Cloud Models Mosquito kit.

For those who don't know it, it's a 54 inch 'sport scale' model. and it comes with a nice pair of obechi veneered foam wings, and several plastic mouldings - 2 fuselage halves, 2 lower nacelles, and 2 upper nacelles. Apart from that, there are a whole lot of laser cut formers from light ply, and a tailplane, elevators, and fin from 3/16th balsa.

So I'm hoping it's going to be a very quick and easy build!

These are the wings - with a pre-machined slot which defines the aileron cut outs.:-

They provide a cut-out in the lower surface veneer for the aileron servos. But I've had a few models with aileron servos in underside of the wing which tend to grab in the long grass and cause stripping of the servo gears, So I am going to go for torque rods, and servos mounted inside the fuselage instead.

In fact ,I'm going to use the Andy Blackburn design torque rods from the Jet Provost (2014 mass build ), because I was so impressed by how smooth and positive these are. Are these really his design? If so, he should apply for a patent!

So, to fit the torque rods, it is necessary to chop the trailing edge off the wing panels, and glue some 1/4 inch strip onto the main panel, the trailing edge piece, and the aileron:-

The wings are only intended to be 'sport scale' so the profile is chosen for performance and ease of build rather than perfect scale, which is fine for me. But I think it should be possible to improve the shape of the wing tips.

As far as I can ell, the trailing edge of the tip should blend smoothly into the trailing edge of the wing panel. So I thinK I need to add to add a bit of material to the tips to achieve this. Which will make the span a bit bigger.

The Andy Blackburn torque rods are made from 5/32nds inch aluminium tube, running in a blue snake bearing.

The ends are made from bent piano wire, epoxied into the aluminium tube. To fill the gap between the wire and the tube, I find it convenient to epoxy a piece of glass cloth to the piano wire, and when dry, wind it round the wire with a bit more epoxy impregnation and tape it up until cured. If you add too much fibreglass, it's easy to sand it down again until it fits in the tube.

Finished torque rods:-

Since I don't need the servo cut-outs in the lower surface, I am going to try to repair them, and reinstate the strength of the wing skin as much as possible.

I cut the circle of veneer away from the core, then created 2 crescents of 1/32nd ply which I pushed under the veneer. I used gorilla glue on these crescent pieces, in the hope that it would expand and fill the gaps, and bonded the circle of veneer back in the same way.

Then filled any gaps with lightweight filler.

[Andrew Mawman]

I've fancied having a go at one of these for years, keep it going

[IanN]

I've had one of these for a while, as yet unstarted, but having done a few experimental "dry runs" the fit of all the plastic parts does seem as if it may be a bit of a faff and I've seen quite a few comments from other builders that found the same. I think the kit is a hangover from the day when any prefabrication was seen as a selling point

Bottom line is that whether you succeed with the plastic, or resort to doing your own thing with trad formers and planking, the kit was still imo very good value for money at the £55 it cost when I bought one from the now defunct Galaxy Models. Costs a bit more now

Watching with great interest to see how you find it

[Scott Edwards 2]

Looking forward to seeing this one grow. Did you get it from The Balsa Cabin ? They normally have one hanging up .... many times I've thought .... hmm, shall I .... Was worried about the wing section and short nose though. Watching with interest !

[Steve McLaren]

Thanks for the heads-up on the plastic bits Ian. I've not built anything with construction quite like this before, so we'll just have to see how it goes. Like you say, If I can't get it all to fit, there's always the old traditional solution.

Yes I did buy it from the Balsa Cabin Scott. Like you, I have looked at it hanging there in previous years, and thought 'No- I've got too many other things to do', but this year I had nothing else on the build board. I think I paid a little over £80 for it which still seems like very good value. I paid about that much recently for just a pair of foam wings.

A little more progress today. I cut some channels into the trailing edge 'spars' and epoxied in the torque rods.

Then stuck the trailing edges back on.

and the extended wing tips.

Yes I know they're a funny shape! but hopefully there's enough material there that I can round them off a bit more.

So then I started on the fuselage. It's all built around a self -igging light ply battery box.

to which you then add add some light ply sides and formers.

The idea is that you build a sort of light ply skeleton to which you then add the plastic mouldings.

The wooden part is going together very well. The laser cut parts all fit together perfectly so far. But I haven't got to the tricky bit yet!

[leccyflyer]

Nice job on the extended wingtips. My clubmate Jim has recently completed one of these for electric and she flies well, but he noted the stubby wingtips and was looking at reworking those. Here's a couple of piccies of his model in flight, with a rather unique IAF colour scheme.

[Andy Blackburn]

Ooh - nice. What mark Mosquito are you going to do? Your new wingtips look a *lot* better than the kit ones.

You haven't mentioned it so far, but is there any washout on the foam cores?

[Steve McLaren]

Andy, Yes there is some wash-out. Measuring from the foam outers which the wings came in, it looks like the trailing edge is 6mm high at the tip, on a chord of 130mm. So that would make about 2.6 degrees. Sounds about right to me??

I'm thinking B Mk IV. Mainly because the kit comes with the clear nose moulding and the smooth exhaust mouldings. I'm still trying to narrow down on the colour scheme - have seen a few I like so far.

[MattyB]

Just took a look at the plan, and I have to say that section does not look conducive to a good glide performance - it's flat bottomed and rather thick. It will fly, but will require quite specific conditions - not much wind on a big hill. My Dad has an old Clark Y sectioned PJ Models Hawk with a very similar section; it flies, but very slowly and it isn't much fun on anything other than a massive cliff site. Based on that I think I would either build this as an electric or bite the bullet and construct a more suitable wing for PSS.

Edited By MattyB on 16/11/2015 22:09:36

[Steve McLaren]

Hmm, that doesn't sound too promising Matt. Scott was expressing the same concerns. And Andy thinks I'll have to add half a pound of lead to balance all that tail! So my cunning choice of a great value, quick assembly, PSS model is not looking so clever now!

I won't give up hope completely, but it seems I may have to hedge my bets. I was always planning to build in the wiring for the motors anyway, so if it just doesn't work for PSS, it may not appear on the slopes more than once!

[Phil Cooke]

Matt - I think the wing section on the plan as per the link is a little 'schematic' or 'cartoony'. It certainly doesn't look like the section you can see sat in the foam beds in Steve's first photo - that looks far more suitable to me - quite Eppler like - its not flat bottomed as per the plan drawing anyway...

[Matt Jones]

I agree with Phil.

Subscribing

[Andy Blackburn]

I agree with Phil; I think the wing section will be fine.

 

I do think you'll have to come up with some imaginative scheme to get the weight forwards - I wasn't joking about having to stuff a battery in each spinner.

Edited By Andy Blackburn on 17/11/2015 23:18:29

[IanN]

IIRC, the kit is designed for the bomb aimers canopy to come off so you can shove as much battery as will physically fit right up front in the fus

I suspect that, without the weight of motors, that in itself won't suffice

[Robert Armstrong 2]

Probably a naive suggestion, but why not put weight equivalent to the motors in the cowlings? Then it should be as easy to balance as the original designer's intention and if you have to go electric after all you won't have built in inaccessible weights which have to be removed. Especially as you intend to build in the wiring anyway might as well include the motor mounts as well

Edited By Robert Armstrong 2 on 18/11/2015 09:31:03

Edited By Robert Armstrong 2 on 18/11/2015 09:32:12

[leccyflyer]

The easiest way to add such weight would be in the spinners, as well as in the nose. That's whatI've done with my funfighter PSS conversions - secured the spinner with a captive nut and heft bolt, then filled the spinner cavity with lead. Gets the weight as far forward as possible, so you need less of it - plus it's easily removed. I would also be inclined to build the model so it easily converts between electric and PSS. The Mossie was, afterall, the first real MRCA.

[Daren Graham - Cambria Funfighters]

Posted by Steve McLaren on 17/11/2015 21:00:22:

Hmm, that doesn't sound too promising Matt. Scott was expressing the same concerns. And Andy thinks I'll have to add half a pound of lead to balance all that tail! So my cunning choice of a great value, quick assembly, PSS model is not looking so clever now!

I won't give up hope completely, but it seems I may have to hedge my bets. I was always planning to build in the wiring for the motors anyway, so if it just doesn't work for PSS, it may not appear on the slopes more than once!

Just a thought but why not give Phillip Knight a call at cloud and he will tell you what section he uses. Just Google Cloud models, he's very helpfull I know as he manufactures the Funfighters for me.

[Andy Blackburn]

Posted by Robert Armstrong:

> Probably a naive suggestion, but why not put weight equivalent to the motors in the cowlings?...

Not a bad idea, IMHO - I had a Balsacraft Hurricane several years ago with a similar arrangement, the scale "PSS" spinner was mounted on a liteply box that contained the battery and a bit of balance weight; it was a tight push-fit in the existing motor box.

Edited By Andy Blackburn on 18/11/2015 12:44:13

[Andy Meade]

My Me262 awaits its dogfight Steve!

Great progress, ready for April?

[Steve McLaren]

I hope it will be ready well before April Andy. I understand the mass build will start late Feb, so I want to be clear for that.

I printed a couple of wing sections today and compared them to the foam cores. I reckon it's closer to Eppler 205 (but with a slightly more pointed leading edge) than to Clark Y.. That's got to be good news right? But good enough?

But as suggested by Daren, I did also refer the question to Cloud Models, so hopefully we'll see what he says.

All this talk of where to put all the lead is focusing my mind on how to lighten the tail end!

[Daren Graham - Cambria Funfighters]

In my PSS Me 109 I used a 4 cell Nimh pack in the nose, weights in the spinner and instead of the usual pushrod I put a lightweight snake in the tail for elevator. Also the elevator servo as far forward as possible. If you consider I used no other ballast and normally it would have a 32 2 stroke up front it worked well.

[MattyB]

Posted by Steve McLaren on 19/11/2015 21:20:05:

...I printed a couple of wing sections today and compared them to the foam cores. I reckon it's closer to Eppler 205 (but with a slightly more pointed leading edge) than to Clark Y.. That's got to be good news right? But good enough?

I guess their online "plan" must be less plan, more extremely rough sketch then! Given that's the case then yes, I agree it should fly fine - there are better sections out there for general slope and PSS IMO, but E205 should give you enough soaring ability to ensure the model will be flyable in a decent range of conditions.

[Matt Jones]

If it is E205 then you're quids in, it's a great section for slope models and has been used on many, many PSS models with great success

[Erfolg]

I totally agree that E205 is a very good section. I use it on my electric power planes. Although I have been told once or twice it is totally unsuitable. Compared to Clark Y I think the benefits come from having less camber @ 3% (comp 3.5)and being a little thinner @ 10.5 (comp 11.7%).

I am not sure about any sharpness in the LE as this does tend to lead to sudden flow separation, even if the nose radius is small it needs to be a smooth curve

As a gliding section it has worked well on all my Sagittas, having good (although not exceptional) low speed characteristics. Yet put the nose down, it not only lifts its skirt and moves forward, it also exhibits a good glide ratio, covering large distances with little height loss.

May be an old section, particularly compared to MH 32 but pretty good non the less.

[Steve McLaren]

The official answer on the wing section from Phillip Knight at Cloud models is that it is Eppler 205. Which is very good news - it sounds like I'm still on track for a PSS model.

The wings are now joined, the aileron hinges fitted (at least temporarily) and the tips sanded to their rough shape.

The fuselage frame is also complete.

So now it's on to the trickier tasks of making all those plastic bits fit properly.