Scruffmeister Posted May 2, 2015 Share Posted May 2, 2015 Just started the build of my Wot4 Mk3. I've not built one of these before nor am I an experience builder so please feel free to chip in. I do have a few questions to get things started: 1) the instructions say the bulkhead (firewall) is in two pieces that need to be joined, but a single 1/8" part seems to have been supplied. Presumably this is a change since the instructions were last updated, but the real question ... - is 1/8" sufficient for the OS 81 FSa engine I will be fitting? 2) Has anyone got any info on mounting the elevator servo in the rear. This seems like a viable option with an engine at the heavier end of the scale? Edited By Scruffmeister on 02/05/2015 20:44:37 Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 2, 2015 Share Posted May 2, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Rob Tothill Posted May 2, 2015 Share Posted May 2, 2015 Hi scruff, I recently built one of these, and I'm also quite an inexperienced builder, so I'll hopefully be able to give you the beginners perspective. I can't advise about the firewall as I think mine came with a 1/4" one, and only has a 46 2st in it. To get my engine to fit in the cowl I had to set the firewall back 1/2". With the battery just behind the firewall I didn't need any lead. I made a carbon tube pushrod for the elevators, as the wood supplied was a bit flexible. Do you have to decide about the servo early, or could you see how it balances before covering then make a decision? Rob Quote Link to comment Share on other sites More sharing options...
Ian Mat Posted May 2, 2015 Share Posted May 2, 2015 I recently built one of these as a first build and I have to say that I don't have a problem with the firewall, especially when you see how it all fits in. Just make sure you use plenty of epoxy both sides, when gluing it in... I fitted a 46 2 stroke, but have since flown (and slightly crashed it) numerous times, where the engine and firewall have taken the full impact and nothing has come loose. I wouldn't worry about it, just build it and enjoy!! Quote Link to comment Share on other sites More sharing options...
Scruffmeister Posted May 2, 2015 Author Share Posted May 2, 2015 Ian - just to check, I assume you didn't get a firewall in two parts and it really is just the case that the instructions are a bit out of date from the actual parts supplied? Rob/Percy - many thanks for your tips. I'll keep you posted! Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted May 2, 2015 Share Posted May 2, 2015 I think the instructions refer to the two light ply firewalls glued or laminated together on some earlier kits . If its apropper ply fire wall it will be OK. The kit used to use light ply for the U/C mounting , if your kit has that dump them and make them from proper birch ply. With heavier engines there was an option to set the firewall back ; this also helped to accommodate the rear carbs on four stroke engines without lengthening the nose. Quote Link to comment Share on other sites More sharing options...
iqon Posted May 2, 2015 Share Posted May 2, 2015 I have 53 2 stroke fitted and both the rudder and elevator servos are at the rear.....with no problems at all...... Quote Link to comment Share on other sites More sharing options...
Wiltshire Flyer Posted May 3, 2015 Share Posted May 3, 2015 Interesting to read the comments re the fire wall. I've just finished building my Wots Wot and have beefed up the firewall as I had concerns regarding its strength. Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 3, 2015 Share Posted May 3, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Don Fry Posted May 3, 2015 Share Posted May 3, 2015 Small thing, but the undercarriage plate is thinner than the prong nuts used to secure the glass fibre undercarriage version, and it needs a couple of eight lite ply washers glued in so the nuts secure properly. Don't worry about beefing it up, Mr Fosse has some competence as a designer. Use nylon bolts to secure the undercarriage, so the bolt breaks before the plate. Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 3, 2015 Share Posted May 3, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Scruffmeister Posted May 3, 2015 Author Share Posted May 3, 2015 Thanks all, judging by the number of responses there is clearly lots of experience out there for this design as I'd expect!I'm not committed to engine choice yet, so I'd be interested to know what would be your ideal currently available engine for the Wot4 I'm building and why? I'm looking for something that can do big loops, tall stall turns at around 3/4 throttle but doesn't have to be a speed daemon!Edited By Scruffmeister on 03/05/2015 13:50:36 Quote Link to comment Share on other sites More sharing options...
iqon Posted May 3, 2015 Share Posted May 3, 2015 Sc 52.perfect ( although i did say it was a 53 earlier ). power is spot on and cheap, Personally I think your 81fs is too big and heavy. you know the next 10 answers are all going to be different.... Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 3, 2015 Share Posted May 3, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Don Fry Posted May 3, 2015 Share Posted May 3, 2015 An Irvine 53 with a 6 inch pitch prop on mine, performs as you describe Scruffmeister. Built with the firewall recessed 5 mm back from the front edge of the fuselage, every thing balances out, servos installed in the under wing bay,no lead. Closes loop used on the rudder. Tend to agree about 4 strokes in these being heavy. Remember the design is older that 4 stroke model engine technology. An ASP 75 powered example I once knew, had it servos on the tail. Ballistic performance. But it clapped its wings, albeit after severe provocation. Quote Link to comment Share on other sites More sharing options...
Scruffmeister Posted May 3, 2015 Author Share Posted May 3, 2015 I'm starting to think an OS 46AX might be just the ticket. I had one of the ARTF Wot4s a while back with an OS 55AX and it was overpowered (although great fun!). My only concern is that the ARTF will probably come out lighter than a kit built Wotty due to foam wing so perhaps the 46AX could be underpowered on the one I'm now building!?Edited By Scruffmeister on 03/05/2015 16:44:41 Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted May 3, 2015 Share Posted May 3, 2015 My Dad's one with a 30 year old fuselage and a very light wing now has a Saito FA62A four stroke. Sounds too small, but the engine has a very good power to weight ratio and it therefore flies brilliantly with loads of power. It has had many engines (2 and 4 stroke) and the Saito is the best. CSEdited By Concorde Speedbird on 03/05/2015 17:00:52 Quote Link to comment Share on other sites More sharing options...
Stevo Posted May 3, 2015 Share Posted May 3, 2015 Ihad a W4 like scruffmeister..... 55AX AND a tuned pipe... went like a ROCKET. Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 3, 2015 Share Posted May 3, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted May 3, 2015 Share Posted May 3, 2015 46 AX is a lovely motor Scruff but the 4 stroke route is nicer, you get the pull and can fly for a week on a thimble full of fuel John p.s I exaggerate some times couple of nice Saito's in for sale adds by the way Edited By john stones 1 on 03/05/2015 19:44:11 Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 3, 2015 Share Posted May 3, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Scruffmeister Posted May 7, 2015 Author Share Posted May 7, 2015 Thanks for all the advice so far chaps. If anyone has any photos of the firewall / engine mounting on their Wot4s could you post them please? Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted October 7, 2016 Share Posted October 7, 2016 Hi all I just wanted to resurrect this thread as I am soon starting to build a mk3 for my son and I , which I have just bought from Chris Foss. The shops don't seem to have the traditional kit in stock . I didn't want the ARTF with the front hatch for electric , plus I think I will build a much more durable model if it's anything like the kit Acrowot I built last year. There are a number of very experienced flyers on this site and their views would be appreciated. My first question concerns air brakes option. Has anyone had experience of these? Some of my larger planes have flaps and it sounds a fun thing to add some interest? Is it worth adding them or do you think it reduces aileron size and adds too much weight? We are powering it with an OS55ax and tuned pipe so want it to be "fun". Opinions appreciated. ..Tim Edited By Timothy Harris 1 on 07/10/2016 09:08:43 Quote Link to comment Share on other sites More sharing options...
Richard Wood Posted October 7, 2016 Share Posted October 7, 2016 Hi Tim, The mk3 kit is very good quality & a great flyer - good choice! An OS55AX will no doubt be a good match. I've built one or two but not with the airbrake option - the model flies very well at low speeds as it is. It might be interesting to have a crack at it though... Quote Link to comment Share on other sites More sharing options...
Keith Evans 3 Posted October 7, 2016 Share Posted October 7, 2016 Hi Tim I built one of these for a friend a few years back .It flew just as well normally ,I never saw this but was told that when the air brakes were deployed it was like hitting a brick wall and dropped dramatically although safely . Get plenty of height when you first try it . Quote Link to comment Share on other sites More sharing options...
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