WOT 4 FOAM E - engine wobble

[Rene Chinnery]

Having returned to R/C flying after 40 years a lot has changed!

Bought a WOT 4 electric foam model which I have flown several times - it's a good re-introduction trainer. Landings have occasionally been on the rough side and the undercarriage has been glued back on more than once!

Looking at the engine it wobbles quite a lot with there being nothing much keeping it in the fuselage other than the engine mount which clamps a foam bulkhead.

How should it be attached and can one correct too much movement?

Thanks

[Colin Carpenter]

A common enough fault. Seen it in all of the Wot Foam E's ! If it gets too bad the change in thrust line as throttle is used will kill the model ! You will think it's radio !! Simply get Gorilla glue , UHU , or similar in there as best you can ! I got two repairs in before the third failure which killed my Acro Wot 😥😥 Colin

[Dave Hess]

Mine's the same. It doesn't affect the thrust-line because it's only the foam behind the engine mount that gets compressed. To fix mine, I just stuffed in a load of expanded polystyrene balls, then poured in some foam-safe cyano and activated it when it had soaked down far enough.

[Rene Chinnery]

Thanks guys that's really helpful. Is it possible to get the WOT 4 with a built-up balsa / ply fuselage (self build is OK) and foam wings? Strikes me as a good model so worth keeping it.

[Dave Hess]

There's nothing to stop you building a balsa fuselage, but if I wanted a new fus, i'd make one out of foam-board, like the Flitetest planes. I would think about an hour from start to finish.

[brokenenglish]

Posted by Rene Chinnery on 27/12/2018 18:33:32:

Thanks guys that's really helpful. Is it possible to get the WOT 4 with a built-up balsa / ply fuselage (self build is OK) and foam wings? Strikes me as a good model so worth keeping it.

Yes. Google Chris Foss kits and that's exactly what you get. The wings are veneered foam I think.

Also, IMO, the Max Thrust Ruckus (and so probably the Riot as well) is far superior to the Ripmax foamies in terms of nose strength. The foam around the motor mount area is thicker and far more robust. The foam around the Acrowot nose (and rudder) is far too flimsy. That's one of the reasons I switched to a Ruckus, and the problems disappeared...

[Geoff S]

I assembled a Wot4 Mk2 ARTF and fitted an electric motor a few weeks ago. I'm very impressed with it as a great winter hack.

Wot4 Mk2 ARTF

Geoff

PS I would agree about the Riot.  It's a very rugged model. A bit heavier than the foam Wot4 but I fly mine in strong winds without any serious problems.  Not tried the Wot4 in strong wind but I think it will be fine.

Edited By Geoff Sleath on 27/12/2018 21:04:27

[Old Geezer]

The Wot4 Mk2 artf is excellent in windy conditions, with just sufficient inertia to be less affected by turbulence than any foamy - particularly important when getting back onto the ground - a further bonus being the ultra short take off available into a brisk wind. With the right motor/prop/LiPo set up just give it the beans and it's off the ground and climbing at 45 degrees from stationary in less than 10-15 feet.

[PAUL HUTCHINSON 2]

Guy's can you advise what you would use if the whole motor mount had ripped the front of the foam e out after a rough landing. Would uhu/gorilla glue/super glue be ok?

If gorilla glue, which one would you recommend?

Cheers

Paul

[Ray Wood 4]

Hi Paul,

Poundland 5 minute epoxy £1.00, the White Gorilla woodworking glue would also work fine depends if your in a hurry

Regards Ray

[PAUL HUTCHINSON 2]

Thanks Ray, appreciate your help

[ron evans]

Just a word of caution about Poundland 5 minute epoxy.

I bought some last year to mend a broken concrete garden ornament, and it worked very well.

However, although I used it outdoors, the very strong smell was unmistakably polyester and tested on blue foam it did tend to melt it.

It's possible other stores may stock proper epoxy, so test on scrap foam first.

Ron

[PAUL HUTCHINSON 2]

Guy's just thinking, I have some 5 minute araldite epoxy and other 5 minute epoxies would they be as good at sticking the EPO foam?

I will test a small area first but wanted your opinion first

Sorry for all the questions

Paul

[Rene Chinnery]

I fixed this problem on my wot4 using ordinary gorilla glue - it appears to push itself as it expands into the foam and tightens around the engine bearer. OK it's a brown colour but the repair is really solid

[John Lee]

The following is an extract from a typical Multiplex instruction manual. Multiplex uses their own proprietary EPO labelled 'Elapor' but it is very similar in characteristics to other EPO's so I'd be vary weary of using epoxy, and if you do test thoroughly:

"Important note
This model is not made of styrofoamTM, and it is not possible to glue the material using white glue, polyurethane or epoxy; these adhesives only produce a superficial bond which gives way when stressed. Use medium-viscosity cyano-acrylate glue for all joints...."

UHU Por also does a good job & some of my Clubmates use Gorilla glue successfully, personally I find it messy & unsightly.

My standard methods to spray one half with activator & allow it to evaporate off. Use medium cyno (I prefer green Zap) on the other & bring the parts together. It produces a bond stronger than the components with no mess. Do allow the activator to dry off before bonding, it will still be effective but you don't get the crackling, fumes & heat that wet activator generates.

[Engine Doctor]

Best way to fix the faults on a foam wot 4 is to buy a Riot instead , up the power to the 4s set up and your away .

Just my opinion having flown both models many times. Please don't start a bun fight .

Failing that get some DeluxeMaterials "Foam to Foam" adhesive in the joint . Excellent stuff with good bond and decent gap filling properties . Will have to be left to harden for a day or so 

 

Edited By Engine Doctor on 17/11/2020 10:19:58

[MattyB]

Posted by PAUL HUTCHINSON 2 on 16/11/2020 16:19:47:

Guy's can you advise what you would use if the whole motor mount had ripped the front of the foam e out after a rough landing. Would uhu/gorilla glue/super glue be ok?

If gorilla glue, which one would you recommend?

Cheers

Paul

Gorilla (PU) glue would be my preference, but I would also embed some carbon strip across any breaks in the foam to prevent any recurrence of the issue. You could do this at the same time as you glue on the front end or afterwards (jut slit the foam, push in the carbon strip then use CA or foam safe CA to anchor it in place). This is very effective in EPO models - my Durafly Excalibur has been reinforced using this technique after many of the early models had structural failures, and after 200+ flights it's still going strong.

[PAUL HUTCHINSON 2]

Thanks guy's, great to see sooooo much help and advice

[Mike T]

It's an odd mounting system, with a base plate embedded in the foam to which the mount itself is screwed. It's possible to goop-up the base plate with filler and adhesive. I used pieces of spare foam salvaged from previous wrecks fixed in place with thick and thin cyano.

If the nose is completely off or damaged beyond salvage, then a nose-ectomy is called for, with a prosthetic bulkhead and motor standoff from liteply, like this:

The standoff was to use the 'overhung' X-mount for that particular motor. The original metal mount could be screwed directly to the bulkhead if using the original motor.

PS - the bulkhead provides a firm fixing for the cowl as well, thus resolving both 'wobbly motor' and 'wobbly cowl' problems.

Edited By Mike T on 17/11/2020 16:00:17

[PAUL HUTCHINSON 2]

That’s a fantastic idea, what did u use to stick the bulkhead to the front of the fuselage?

cheers

paul

[Mike T]

Just thick cyano, Paul. When its cured, wick in some thin cyano as well, to make doubly sure.

You could also drill some 3mm holes through it to take bamboo barbecue skewers for extra 'anchorage'.

[David Davis 2]

Posted by brokenenglish on 27/12/2018 20:47:17:

Posted by Rene Chinnery on 27/12/2018 18:33:32:

Thanks guys that's really helpful. Is it possible to get the WOT 4 with a built-up balsa / ply fuselage (self build is OK) and foam wings? Strikes me as a good model so worth keeping it.

Yes. Google Chris Foss kits and that's exactly what you get. The wings are veneered foam I think.

Also, IMO, the Max Thrust Ruckus (and so probably the Riot as well) is far superior to the Ripmax foamies in terms of nose strength. The foam around the motor mount area is thicker and far more robust. The foam around the Acrowot nose (and rudder) is far too flimsy. That's one of the reasons I switched to a Ruckus, and the problems disappeared...

Rene, you have lots of WOT 4 options.

1. The standard size WOT 4 Almost Ready To Fly.
2. The standard size WOT 4 Almost Ready To Build kit, which as Broken English has sugested has a foam veneer wing. Both of these will need a bigger electric motor and battery than that installed in your WOT 4 Foam-E. Then again you could always fit nice 46-53 two stroke glow!
3. The "Three Blues ARTF," so called because the model is finished in white with blue trim in three different shades of blue. This model is the same size as the WOT 4 Foam-E and takes the same size servos and motor as the WOT 4 Foam-E. **LINK**

Of course they may not all be in stock.

There used to be an ARTF WOT 4 finished in white with blue and black bands on it. It had a reputation for being tail heavy and for being a poor flyer once the cg was correct.

That said, my experience of flying WOT 4s is limited to kit-built and ARTF WOT 4s powered by i/c engines, the WOT 4 Foam-E and the much larger WOT 4 XL.