Fun Flys and Foxes' Paws

[David Davis]

SLEC Fun-Fly: Build Blog Complete with Fox's Paws!

Introduction.

The two gentlemen in the picture, holding their SLEC Fun Flys, (Fun Flies?) are both members of my former club, the Shropshire Model Fling Club, or SMFC for short. Alan Ayres' model, on the left is the earlier product with a foam wing. Kit Davidson's is the later version with a built up wing featuring lite-ply wing ribs. As you can see, both models are finished in yellow, Alan's is covered in film while Kit's is covered in Solartex and features RNAS markings as befits a man who spent his working life in the Royal Navy. The diagonal velcro strip on the port wing is to enable the installation of a Mobious camera. Alan's model is powered by an OS 35SF while Kit's has a Thunder Tiger GP 42. I've flown Kit's model on several occasions and found it to be very impressive, it goes exactly where you put it and it's very easy to land. A most enjoyable model to fly.

The model is a shoulder wing design which is easy to build. The kit contains a very explicit set of instructions with forty-five photographs illustrating the construction process. It would make an ideal first build for someone who has learned to fly on an ARTF trainer and perhaps followed it up with something a little more advanced, but who is looking forward to building, as opposed to assembling his first model. The fuselage is made up from lite-ply sides connected together by formers which fit into slots in the sides, so it's difficult to build it out of true. The top and bottom of the fuselage are made up from balsa sheet. The wings feature a semi-symmetrical wing section and the tail surfaces are made from balsa sheet. The kit is extremely comprehensive and includes an engine mount, spinner, fuel tank, undercarriage, pushrods and horns. I do not propose to give a blow by blow account of the construction, the building instructions and photographs do a good job of that, but if I come across any problems, I will let you know.

Having retired to rural France I treated myself to a kit as a Christmas present to myself and was going to finish it in yellow to match the other two but Kit persuaded me to finish it in orange to match my National Coal Board orange overalls. These overalls are sometimes referred to as my “Guantanamo” overalls by various jolly fellow club members but I've been insulted by experts in the past so it just bounces off me. They were brand new and cheap because few people have the self-confidence to carry off orange! They are also beautifully made of a very heavy material which keeps me warm in the winter and which protects my clothes. Furthermore, they are also fire resistant so should I be unfortunate enough to be caught in a fire while wearing them, with the aforementioned jolly fellow club members in attendance, we'll see who'd be laughing then!

Having decided to finish the model in orange film, I was in the model shop in Whitchurch while collecting more stuff from “home,” when I bumped into another SMFC member. I told him of my decision to finish the model in orange. He said that it would be a good idea as three yellow Fun Flys in the air at the same time would be a recipe for disaster!

The model is supposed to be suitable for engines of 25-48 cu.ins though an electric powered version is also available for those who like that sort of thing. The works demonstrators were flown with OS 32 SF engines. I felt that a four-stroke would be too heavy for this model and the only two-stroke which I had available in this range was a Super Tigre 40 which I thought might be a bit too much both for the model and for limited flying skills. So I bid on a superb red Irvine 36 advertised on eBay and missed it by £1, but the same advertiser had an old but sound-looking SC 32 for sale. I bid the minimum amount and won it. It has a small torpedo silencer and will probably be a bit of a barker. I plan to test run it over the next few days to find out. I hate noisy engines so if it is noisy, I will have to see whether I have another silencer which will suit it. If not an email to Just Engines will be in order.

[David Davis]

Fox's Paws: An Explanation.

In the 1980s I had a girlfriend who told me that she'd “made a fox's paw”. I had never heard the expression before and had to have it explained to me. It means a “mistake.” No she wasn't referring to me, we are still good friends three decades on! It's an Anglicisation of the French “faux pas,” which means a “mistake,” or more literally, a “false step.” It was apparently widely used in the Bohemian circles of South London within which she moved at the time. Despite having built lots of models, I have already made two fox's paws in the construction of the fuselage and it's not even finished yet but I was once encouraged to improvise, adapt and overcome, so I have done!

The Build: The Fuselage.

I don't know exactly how many models I've built since I built my Keil Kraft Ajax fifty-six years ago but it must be at least twenty or thirty and that does not count finishing other people's abandoned projects or rebuilding the wrecks left behind in SMFC's “Boot Hill Corner!” However, despite all of this experience I made the first fox's paw virtually straight away when I started building the Fun-Fly! I glued the undercarriage block to the fuselage sides alright but such is the inadequacy of my spacial awareness, that despite having a photograph to refer to, I epoxied the block behind the former slots instead of in front of them! They have therefore become so much dead weight or “local fuselage strengthening!” However, I always thought that the undercarriage supplied with the kit was something of a weak point so I made up an under-mounting plate from two layers of 1/8”ply. I intend to fit an undercarriage from a dead Foam-E WOT 4 to start with, despite that model weighing a mere 1.1 kg while the Fun-Fly weighs 1.8 kgs. What do the cognoscenti think? If it's not strong enough I have other options!

[Geoff S]

I built a couple of the earlier SLEC (Precedent) Fun Flies with foam wings.

I had an Irvine Q40 in he first which was much too powerful for my pre A certificate self and I replaced with a Super Tigre G34 which was perfect and one of the best engines I ever owned (still got it somewhere). In fact I passed my 'A' with it and it met it's Waterloo when the battery went flat as I was on the down side of a stall turn - lesson - don't do a quick recharge when an unexpected winter flying day crops up.

I liked it so much I built another and I think it only took a week from start to test flight. (I was a fast and enthusiastic builder then). I can't remember what happened to that one. The main fault with the structure was the fuselage weakness around the shoulder wing. One of mine broke in half after blowing off my stand and the inertia of the engine was enough to snap the fuselage when the wing tip hit the ground.

I've been tempted to build another with a built-up wing and electric power but life's too short to build 3

Geoff

[Redex]

Just as a reminder - within the forum there are some other build blogs for SLEC FunFly's, including leccy info for those interested.

[David Davis]

The Second Fox's Paw.

 

The second mistake occurred when I had the fuselage fully assembled and ready for glueing. The instructions and photographs are very clear on this, you assemble the fuselage up to and including the former at the leading edge of the wing, marked F5 in the case of the Fun-Fly. You fit the servo mounting plate and the the wing fixing plate former, marked F13. Having checked that all is square, you then run glue, thin cyano in my case, into all of the joints. This is what I did, but I had omitted to include the wing mounting plate! By the time I realised my mistake, not only was the glue dry but the firewall was also epoxied firmly into place. The mounting plate is supposed to locate in three slots, one in the former at the trailing edge of the wing and two in the fuselage sides. There was nothing for it but to epoxy two pieces of scrap ¼” spruce to the undersides of the fuselage slots, to saw off the lugs from the plate, to epoxy the plate on top of the spruce strip and to add some shaped lite-ply to the top of the plate to clamp it into the correct position. The plate's rear lug simply glued into the former as it was supposed to. I expect I'll have to alter the wing centre section to allow for the alterations. The redundant slots in the side of the fuselage will be filled with scap balsa.

 

The pictures show the model set up in my SLEC fuselage jig; not really necessary but as I've got one I decided to use it! They also show the “modified” undercarriage and wing mounting plate.

 

More Fuselage Musings.

 

1. The instructions tell you to place scrap balsa at the rear of the fuselage to represent the thickness of the fin and and tailplane, to glue the tail-blocks into place and to shape them using a razor plane and sandpaper. I did this using aliphatic glue and having allowed it to dry overnight I began to shape the tail-blocks. As they were only glued at the front, they soon came unstuck. I solved the problem by drawing round the fuselage contours which gave me two lines to work to. I then shaped the blocks in a rough and ready way and I will finish them off neatly to the fuselage profile. Picture below.

2. With just about every kit I've ever built, I've incorporated a closed loop rudder. In the case of the Fun-Fly the rudder pushrod is supported throughout most of its length so I've left things standard.

The built-up nose block is posing a few challenges but I'll let you know how I get on later.

The photos will be posted when I've worked out how to retrieve them from this new computer!

Edited By David Davis on 30/01/2016 13:50:11

[David Davis]

Nice man who runs the computer shop in Aigurande showed me how to find pictures I had lost in my lap-top's memory! I've had some difficulty in uploading the picures but here they are as a warning to you all!

"Modified" wing fixing.

Fuselage in jig, clamp holding the firewall in placewhile the epoxy dries.

Tail block marked up for planing and sanding.

[David Davis]

The Wing: A Most Interesting Form Of Construction.

Having got the fuselage to this stage I decided to make a start on the wing. It is largely made up of lite-ply with balsa sheeting and balsa leading and trailing edges.

You begin construction by pinning the lower spar, made from 1/4 square hardwood to the plan. SLEC provide you with a similar length of 1/4 square balsa which is pinned where shown on the plan, to hold up the semi symmetrical wing ribs, and then you build the first of three sub-assemblies. These are the centre section of the wing and the two aileron servo boxes which are glued to the centre section. The picture below shows one of the aileron servo boxes in the course of construction, before glue was applied.

All of the lite-ply components fit together very tightly. At first I was tempted to open up the slots with a small file but I found that by applying a little more muscle they all snapped together and I glued them into place using cyano. A first for me!

The wing ribs are then glued to the spar. Between each wing rib is a spacer which also acts as an inter-spar web; this is also made of light ply, Part No: W57. These are glued to the spars and also fit into a slot in each wing rib producing a strong mechanical joint which is strengthened by the glue. Furthermore the tabs on the sides of W57 are not identical, being male and female, i.e, each web goes through the wing rib and slots into the web on the other side further increasing the strength of the joint. I wish I had taken a picture of the part before using them all in the wing construction because a picture would give a much clearer explanation of the construction than words can.

However, I found out that as I proceeded to build the wing, the ribs did not match their positions on the plan. I'm told that if a carpenter, making a staircase, makes a small mistake with the first step, then the mistake becomes much larger and more obvious when he reaches the top of the structure. Fearing that I had made a similar mistake, I removed the lite-ply leading and trailing edges from their sheets. These two components, parts W59 and W60 respectively, have small holes machined into them to suit wing ribs. I'm pleased to say that they matched my structure perfectly so they were snapped into position and glued into place. I suspect that something has gone wrong in the printing of the plan. The picture below shows my dilemma.

Having thus reassured myself, I proceeded to build the port wing which fortunately matched the other! Before going off to choir practice last night I had started the wing sheeting. Pictures to follow.

[David Davis]

Foxes Paws Department: Wing Ribs.

The SLEC Fun Fly features semi symmetrical wing ribs. While building the first wing half, I could not understand why one of the ribs did not sit neatly on the 1/4 inch balsa wing rib alignment strip. Of course I had fitted it upside down! My notorious sense of spatial awareness strikes again! As it was already glued into place I had to cut it out. In the process I destroyed the front section of the rib and had to make up another from stock plywood. For the port wing I decided to write the word "TOP" on each of the wing ribs while they were still in their sheets. Eagle-eyed readers may have noticed that inscription in the picture of the aileron servo box above!

Edited By David Davis on 24/02/2016 07:17:37

[David Davis]

Just a quick note to advise you of progress so far.

I've sheeted the wings...

... and it's beginning to take shape!

It starts to get exciting when the kit-box starts to empty.

[David Davis]

I reached the stage of fitting the rear fuselage blocks into position. This time I glued them to the fuselage with epoxy and learned from other threads that you should sand them to profile with the scrap balsa, representing the fin and tailplane, pinned into position. I discovered however that I had planed away too much balsa from the blocks so I glued some sdrap balsa into place and sanded it down with my new triangular sander which I find very useful.

[David Davis]

After sanding it didn't look too bad.

 

At the time of writing I have been unable to finish covering the fuselage through lack of orange Profilm. As I explained above I had intended to cover the model in orange in order to match my overalls, see picture below, NCB overalls and an Akubra hat, de rigeur for any fashionable areomodelliste this season! However, as I've run out of orange, I've decided to cover the top-sides in white. I'm eagerly awaiting the arrival of more Profilm.

Edited By David Davis on 11/03/2016 10:04:18

[David Davis]

Fuselage and tail surfaces covered and epoxied into position. Just waiting for the glue to dry.

[David Davis]

Pleased to report that the maiden of the SLEC Fun Fly was successful. It was rather windy on Sunday (10th April 2016) so I flew the ARTF Stick 1500 first as I don't really mind if I crash that one!I managed quite a long flight with a landing on the 10 metre wide runway, however, I clipped the prop on landing and filed a few millimetres off one of the blades. Then I faffed about watching others fly, thought about flying the Gemini instead, thought about not flying the Fun Fly but finally decided that I was a competent enough pilot to maiden the model even in a stiff breeze, so off I went.

The take off didn't go in the direction I'd planned but I soon got hold of it. It required a fair bit of up trim and a small amount of left aileron but after that I just flew it about on low rates most of the time. Loops, rolls, immelmans, (immelmen?) even a Cuban Eight, then I decided to quit while I was ahead. I brought her in somewhat hesitantly and on finals I heard Fabrice, the club's treasurer, who had just arrived, shout out, "Sur la piste!...Sur la piste!" which means, "On the runway!" I'm pleased to say that I put her down on the runway, without clipping the prop and taxied her back to me. It was not my best landing ever but it was a maiden flight and there was no damage; better than some of Fabrice's later landings with his Goldberg Piper Cub! Then I flew the Gemini and managed to land that on the piste, again, it was not a perfect landing but I'm still getting used to that model too.

I got Roger to take a couple of pictures of your humble servant posing with the model in my NCB suit which matches the colour of the model! I'm going for a haircut and beardtrim on Tuesday. I may even dispense with the winter whiskers, they make me look like a badger or a homeless person! Perhaps I'll opt for an aviator's moustache.

[David Davis]

I wanted to put this bit under the last picture but my inadequate computer skills couldn't position the cursor in the correct place.

 

So what are my conclusions about the kit?

Firstly, the finished model is an excellent flyer.It goes exactly where you put it and is capable of more manouevres than I am. I really enjoy flying this model, perhaps I'll learn to knife-edge with this one! Furthermore, the kit contains everything you need to build the model except for the wheels, you get a fuel tank, a good length of fuel tubing and all of the nuts bolts and screws, you even get a piece of clear plastic sheet with which to cover the plan.I dispensed with the standard single wire undercarriage because I'd seen them bend the wheels out of track on other people's models. This was an alteration I had planned from the start, the model is fitted with a chrome plated commercially-available undercarriage fitted to the airframe with plastic saddle clamps. The wheels last flew on a control line B. Sichi Sopwith One-and-a- Half-Strutter in the 1980s! The only other alteration I made was to replace the metal strip which attaches the tail wheel to the rudder with a length of cable tie. This was only because I'd made a complete horlicks of drilling the hole in the strip and I wanted to get the model into flying condition for last Sunday. It seems to work alright.

The construction of the wing is somewhat involved but it does produce a very rigid and accurate structure.I used much more cyano in building this model than I usually do, especially in the building of the wing. Having read all of the other threads which deal with the construction of this model, I am not the only one to fit one of the wing ribs upside down, so it's a good idea to label each one with "TOP" while they're still in their sheets!

The fuselage is straight-forward in its construction until you come to the nose section. Here the instructions are simply wrong. Picture 23 for example refers to attaching the tank bay formers "F37 and F38 on the inside of formers F4 and F5 and glue them in place to parts F36." As part F36 is the nose-ring I had to do a fair bit of head scratching before I realised that some of the parts had been mis-labelled both in the instructions and in the photographs.The tank bay formers are parts F38 and F39, not F37 and F38 and they are glued to the tank bay sides F37 not F36.

Am I being pedantic? Perhaps, but I couldn't for the life of me work out to build the cockpit and attach it to the wing, (pictures 35-41 and Figure 2.) In the end I fitted a pair of magnets to hold the front end in place, used a tab and screw at the rear as per instructions and used some velcro strip in the middle for good measure. So far it hasn't blown off.

I noticed that many of the models which featured in other threads do not seem to have been completed. Am I being unfair to suggest that these builders gave up because they couldn't understand the instructions? Almost certainly yes. Perhaps the models were finished but the builders did not finish their threads. Perhaps life got in the way. Marriage, divorce, childbirth, moving house, pressure of work, promotion at work and redundancy are all reasons why models are started but never completed. I'm lucky; I live in retirement in rural France.

So do I think that the SLEC Fun Fly is a suitable model for a first-build for someone who has learned how to fly on ARTFs and wants to actually build rather than assemble a model? Yes I do with two caveats. The model does take a fair bit of time to build and the novice builder would benefit from having the help of an experienced modeller to guide him through some aspects of the build.

Graphics by Tim Calvert of Model Markings.

 

Edited By David Davis on 12/04/2016 07:23:13