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If the ground had been two metres higher, the landing would have been perfect

Repairing a WOT 4 XL once I'd realised how expensive they were!

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David Davis20/07/2018 12:41:48
3232 forum posts
541 photos


I was once asked on some forum which was my favourite model. I chose my WOT4 XL powered by an Enya 120 four-stroke, the cooking engine not the R type.

4  maiden.jpg

While flying it was enjoyable I made a complete holicks of the landing one day and the model dropped straight down from a height of six feet or more onto its wheels breaking the fuselage in half. I put the two halves into the cellar and forgot about them until last week when I was burning undergrowth from my orchard. I picked up the XL intending to chuck it onto the bonfire but before I did that, I visited Steve Webb's website to see how expensive a replacement was.

At over £183 a pop I decided to have a go at repairing it! I pushed the front onto the back as well as I could. I had aligned it as well as possible but there were some bits of wood missing so I fitted into a SLEC fuselage jig and pinned it in place with cyano. It's a shame that I hadn't taken a picture of the two fuselage halves but you'll be able to see the repairs later.

Brief Autobiographical Tangent.

The man who first got me interested in aeromodelling was my Uncle Geoff, my mother's sister's husband, who was a draughtsman and who built superb models during the Golden Age, mainly free flight gliders like the SATU and Jinx. This would have been 1959 or 1960 when I would have been 11 or 12 and he would have been in his early 30s. Within two years he had died of cancer but before he died he gave me all of his models including an incomplete double sized Vic Smeed "Tomboy" which he had drawn up himself. Spool on thirty years or more and I built the model and installed a radio.

double sized tomboy.jpg

However, the fifty year-old wood in the fuselage was very weak so I built another fuselage using cyano throughout. I was very much a beginner at the time and my transmitter didn't have a buddy box facility. Somehow I got it into a spiral dive which hit the ground with great force and all I was left with was a Vintage Yellow Solartex bag of balsawood sticks! Every glue joint had failed. Since then I have only used cyano very sparingly when building models preferring aliphatic on most joints.

The Revival!

Given my previous experience with cyano I was surprised at just how strong and rigid the repaired fuselage was once I'd removed it from the jig. I decided to reinforce the joints with glass fibre mat and resin. Some of it is wing joining tape, some of it is finishing cloth and using glass and resin is not my strongest suit as the photographs below will attest to, however, the repairs have now been reinforced. Having sanded away some excess glue the original servo tray was fitted last night.

I still need to scarf in a few pieces of wood and add a little filler before recovering the fuselage. I also need to repair the elevator pushrod but the repairs are going ahead steadily and I may even fit a glider tow release.

wot 4 xl (1).jpg

wot 4 xl (2).jpg

wot 4 xl (3).jpg

wot 4 xl (4).jpg

Laser Dilemma.

For some time I have been telling my French clubmates about Laser Engines but I haven't had one in a model for years. I thought I'd take the opportunity to replace the Enya with either an old Laser 150 V twin I picked up for strong money at an auction in Exeter a long time ago, or with a brand new single cylinder 155 which I've never run.

My head says fit the 155 as that's just a straight swap. My heart says fit the V twin but there are problems. I cannot fit the stock fuel tank high enough in the model to ensure a good fuel flow to the carburetters. I can squeeze two six ounce SLEC red tanks, one for each cylinder, next to each other in the fuselage but I cannot get them further forward than the F1 former and that may upset the centre of gravity. The other alternative would be to cut away the balsa wood block on top of the fuselage, between the F1 former and the firewall and fit the two tanks from the top but that would involve a certain amount of grief.

I have asked Jonathan Harper at Laser's for advice and he says that an uncowled V twin in a WOT 4XL looks like something out of Mad Max.

I quite fancy a Mad Max WOT 4 XL!

Any advice will be gretfully received.

Edited By David Davis on 20/07/2018 12:46:30

Jon - Laser Engines20/07/2018 13:20:11
4412 forum posts
162 photos

If it helps you can use a radio active 12oz tank and fit it with 2 clunk lines. you can then fill through one of the carb feeds and the overflow will work as normal. The radio active tanks are good as they are not square so you can mount them 'flat' and get the tank c/l a little higher.

Another option to the mad max look could be a hotrod look. Bright colours, flames down the side, that sort of thing.

Tim Flyer20/07/2018 13:29:25
926 forum posts
151 photos

Pleased you are repairing it David . They are great planes . I always keep one running (I have had 3!!) . I think if you use the V twin it will also be madly nose heavy. The 155 will be plenty Ballistic! I have used a 2s OS 120ax in all of mine and it’s a lovely engine and also rather ballistic on a 16x8 prop. A 155 ( I use one in my Wots Wot Xl) will turn a 16x8 fast so it will more than power it . One thing worth considering is UPWARD flapperons for landing. I need and use these on my 120 2s powered version as it will keep on floating with all the power! Another thing is tail mounted servos rather than the rattling push rod . The big Laser 155 will allow that with no added nose weight 😊Enjoy!

David Davis20/07/2018 15:44:32
3232 forum posts
541 photos

Would it be simpler to mount the V Twin inverted?

Edited By David Davis on 20/07/2018 15:54:04

Jon - Laser Engines20/07/2018 22:44:15
4412 forum posts
162 photos
Posted by David Davis on 20/07/2018 15:44:32:

Would it be simpler to mount the V Twin inverted?

Edited By David Davis on 20/07/2018 15:54:04

Only if you can get the tank low enough.

As for weight I think the company w4xl I used for testing the 155 was more or less perfect on the balance. I did have the rx battery way back but it was ok. the 150 twin is not massively greater in weight and also you have the added weight of the repair down the back so it might all work out

David Davis21/07/2018 05:19:41
3232 forum posts
541 photos

Even with the Enya fitted, which is lighter than either of the Lasers, the model flew with considerable up trim. However, I'd fitted the battery beneath the fuel tank so I'll remove it and refit it well to the rear. I hope I haven't epoxied the thing in!

I have ordered a 12oz tank from Radio Active.

David Davis05/08/2018 08:43:19
3232 forum posts
541 photos

Laser 150 V Twin and Radio Active 12 oz tank temporarily installed. One of the advantages of living in La Creuse is that oak and other hardwoods are available faIrly cheaply. The engine is mounted on 8mm square oak strips.

The next job is to repair the elevator pushrod and to fit a glider tow release. Note the untidy state of my workbench. A temporary situation I assure you!

laser v twin temporary installation.jpg

Edited By David Davis on 05/08/2018 08:56:59

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