Piers Bowlan

So something bigger with a slightly higher wing loading and semi-symmetrical wing section I suggest, to enable it to fly a little faster and penetrate a bit of a blow ( UK usual weather). Not so much a trainer but a good second model. One not suited to public open spaces but a club environment.

An interesting experiment and a nice video illustrating the effectiveness of flaps increasing a wing’s camber so enabling the ‘same lift’ but at a lower speed whilst increasing drag producing a steeper glide angle. The ailerons or any control surface will be ‘weak’ at slow airspeeds, it is the first feedback we model pilots have that we are flying slowly, maybe too slowly. What we observe is always ground speed but what we (and the model) are interested in is airspeed. The second indication we are flying too slowly is the incipient spin!

In cases like this more information can be helpful to get to the bottom of what is going on. i remember reading a thread where someone was having problems with a Sopwith Camel (or similar) which had a strong tendency to ground loop. Many suggestions were forthcoming including gyros and altering the wheel toe in/ out etc. Eventually it transpired that a very large lump of led had been attached ABOVE the engine to compensate for a very heavy tail. The resulting high c of g and narrow track u/c was the cause of the models errant behaviour. A lighter tail would helped a lot! Knowing about the lead earlier in the thread would have halved the number of posts. 🤣

Whilst it is true there is not much that can be done about the washout, wing section or a warp Jon, having a knowledge of why the model behaves this way might help us not to build, or buy one, like it again! If Maurice has not already done so he could try adjusting the C of G to see if there is any improvement? Alternatively he could try increasing the aileron differential incase adverse yaw is precipitating a wing drop or even adding a tad of coupled aileron and rudder ☠️. I tend not to take the view, you are stuck with it, just trim for speed and all will be well. If the C of G is out then the model can be speed unstable. If a model is well designed, built and set up correctly, as I have no doubt yours are, the model will behave itself if trimmed for a stable approach.

Whilst I have to agree with everything Jon says here (!) I think there is a bit more to it. Certainly a stabilised approach;-a/c configured early on glide path in trim with approach power set, is the basis for a good approach and landing. To say the aircraft can’t stall is a bit of an exaggeration. Unlike a full size aircraft we have no idea how near the critical pitch attitude the aircraft is to the stall. There are these things called gusts, thermals and sink. Yes we can apply power to arrest the sink but can’t see the airspeed as the model approaches, unlike a full sized aircraft. It’s all down to guess work with a model - no stall warner. So when it’s gusty we fly a little faster, as you do with a full sized aircraft. We know when we have got it wrong however when it departs and ends up in bits 😭. This doesn’t help Maurice with his Chipmunk ‘that stalls at the merest suggestion of landing’. The question is why is his aircraft so unforgiving? As I said before (now deleted!) there are questions? 1. Is it overweight (high wing loading) 2) is there any inbuilt washout. 3) is it always one wing that drops (warp?) 4) differential ailerons would be helpful. 5) is the aerofoil ‘thin’ and unforgiving which won’t help matters. 6) C of G position? As for flaps helping, most aircraft are actually more likely to drop a wing and depart into a spin (incipient spin) with full flaps selected if the speed is allowed to decay below a minimum safe approach speed (especially a high power settings). Answers on a post card please! A little more information about Maurice’s Chipmunk might help possibly.

Sorry, Leccy I didn’t realise GreyAce’s Helios were sub 250g in public open spaces. A Wildthing with big motor and LiPo would be something of a missile and not suited to a public open space by a beginner- agreed 👍

If GreyAce wants too fly in strong winds, better get one of these. The Wildthing 46 being EPP is as near indestructible as you can get. They have been around for a long time and most slope pilots have had one at some time. Designed by Alan Head of SAS (Soar Ahead Sailplane) fame they are now still available from The Balsa Cabin fortunately. No suitable slopes to fly from? No problem, just saw the nose off, attach a ply bulkhead and screw the BL motor to it (20 mins work). I think he may get addicted to slope soaring however if he is able to make the journey to a slope. If he can build/rebuild/set up a helicopter, an electric Wild Thing will pose few challenges. Also, if he has logged 60 hours on his helicopter without crashing it he has obviously got orientation and coordination hacked, so I can’t see him struggling, even in a blow. Tip:- fit a folding prop and have fun 👍😁

My three models to complete now put to one side, - so my bench nice and clear 😁

With formers I usually use the age old technique of pricking out the shape through the plan directly onto the wood, then just join the dots with a scalpel and straight edge (steel rules). With ribs I prick out onto a piece of thin ply, carefully cutting round it into the wood as a template. OK on a parallel chord wing.

Carbon strip from here. The probably do carbon rod too. Here.

If you are going to use carbon rod I would sharpen the end with some sandpaper to a nice point which will make it slide easily into the foam. Just keep an eye on it to make sure it goes in straight! Having made the hole with the carbon rod, withdraw it and push some epoxy down the hole as well on the carbon rod. Gorilla glue could be an alternative. I wouldn’t use cyano in this instance as it may go off before you have it fully in place! I am assuming the model is made of EPO. Philips favoured method is also mine too, carbon strips let into the surface of the foam. The problem is the plastic moulding ‘thingy’ will have to have a slot cut, with a junior hacksaw I suggest, to facilitate the the strip running from the root across the break to reinforce it. Use a sharp scalpel blade to make the rest of the cut in the foam which will enable you to push the strip into the foam. Once in place run thin cyano along the top of the carbon which will wick into the (EPO) foam. You don’t need foam safe cyano on EPO and it does work best on this type of repair in my experience. An accelerator spray will set it solid to form a very strong joint. Two strips could be even stronger. Good luck.

Unfortunately my wife opened the letter with Richard’s Tempest order form in. She said, ‘ Don’t you think you have enough planes in your garage Piers?’ (I think it was a rhetorical question 🤣) Next time Richard mark the envelope ‘HMRC’, she won’t open that! Anyway, cheques in the post, as they say.

Lightly loaded aeroplanes just fly better, whether that is a model or full sized B747. They will fly on less power, land and take off at lower speeds. Needlessly adding more materials to make them ever stronger is counter productive because of the weight gain. One complication I am keen on however are flaps, not just for low speed arrivals but to stop the long float in ground-effect before touchdown. Some years ago I remember watching a friend’s Mossie come creaming in over the threshold at low level before floating the length of the strip. Finally he landed in the ‘rough’ and ignominiously ending up inverted. That is when you do need a tough model! Of course he was coming in like a train because of the fear of the dreaded ‘tip-stall’. (I would have done the same) Flaps? A good servo is all you need in terms of added weight, a good trade off I feel.

According to his website, the Tony Nijhuis 72in Mosquito weighs 14lbs and has a wing loading of 40oz/squ ft. Tapered wings and a high wing loading is not a combination made in heaven. ☠️

David if you scroll down to Pete H’s 2nd post (on page 3 of the La7 Warbird Replica thread). You will find some photos of ‘cutting the ailerons free’. HERE. Regarding your comment about ‘no stringers or internal structure’, a veneered foam cored structure is stressed skin or monocoque so does not need any.

David, veneered foam core wings are sometimes supplied ‘intact’ in that you are required to mark out and then cut with a sharp scalpel the ailerons and flaps (when fitted). You then have to trim off some more material in order to face the cut edges with strips of balsa. These then are slotted to take the hinges. You will also have to bevel the ailerons to facilitate their movement up and down.

Good one Keith, make a change from the ME262 or over modelled A10 Warthog. Thinks; the plexiglas in the front might be a tad vulnerable in a less than perfect landing but it could always be painted balsa. Go on, build one and have the plan published in RCM&E!

More expense ( two motors/ESCs, wiring and bigger batteries) may put many people off a twin? Traditionally IC twins need to be bigger because of the weight, to keep the wing loading sensible. Bigger models take longer to build and a ‘scale’ mossy with its oval fuselage cross section will certainly be more challenging to build, which puts off people who just struggle to build a fuselage that is straight ( I empathise 🤣). HOWEVER, with Richard’s WR USP of simple ‘scalish’ build lines, foam wings and E-power using a couple of ubiquitous 2200mAh LiPos, it could be very appealing indeed ❤️. 60in span could be the sweet spot in terms of span if that wasn’t too big for a couple of 2200mAh batteries?

I will go for that option.

Presumably ply, not lite-ply? Could the retract mounting plate be made thicker- more meat for the screws to bite into ( yum!) Alternatively use bolts poking upwards (wire lock buried heads so they don’t rotate). What I am driving at is, I am fretting about the gear being ripped out after an ‘arrival’ onto none too short grass. Maybe I should just keep taking the Valium or get another hobby. 😉

Foam core wings are easy and quite satisfying to build too. Polystyrene foam is cheap and plentiful. Reinforced with carbon fibre strips and covered with brown paper with PVA, are ridged and quite light too. As an alternative, I can vouch for Bill kits, their wings are well made and reasonably priced. Saves a lot of time too.

Richard is in the ‘business’ of selling kits and probably the reason why there aren’t many kits of the Zero or Nakajima is because there isn’t a lot of demand for them? As for the Betty Bomber Keith I think you could be on your own with that one. We probably all have our own list of ‘interesting’ (kwerky) or sometimes ugly planes to model but they would not be very successful as kits. Personally I think a kit of the DH Hornet would be great in preference to a Mosquito but I don’t think there would be many other takers.

Yes, BEB was a really great contributer and moderator on the forum. Much missed.

Beautiful work, but ... Wot, no pilot! 😮

Either would be good for me Richard.