John Roberts 9 Posted September 19, 2018 Share Posted September 19, 2018 Hello, I have just finished assembling a Wot 4 Foam E Mk2 which I bought to use as a winter hack. Although it went together very quickly and without any issues I was a bit surprised to find that I needed to add 70 grams of nose-weight to get it to balance at the recommended 70mm point. I am using a 3S 2400 Hacker LiPo (185g) which is probably a bit heavier than the 2200 recommended by Ripmax so the need for additional nose-weight was doubly unexpected. The instructions say it ought to balance correctly with no adjustment. I suspect that the model will happily fly with a more rearward CoG and the instructions mention adding tail weight to "provide extra manoeuvrability for experienced pilots" so I will probably find myself removing some or all of the extra weight after its first flight! Anyway, I am just curious to know whether any other owners of this model have encountered the same issue. A friend who owns the Mk1 version confirmed that he didn't need any extra weight to balance so it might be just a Mk2 issue. Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted September 19, 2018 Share Posted September 19, 2018 Ripmax have been very bad on this. Their web site states that there's an error in the instructions, and that the CG should be at 80mm from the LE (not 70). This has been known for the last year or two, but they still haven't changed the instructions! You'll find there are two ballast weights under the fus. at the rear end (keep them!). I diligently removed these, to get the 70mm CG, and it cost me the model... Quote Link to comment Share on other sites More sharing options...
John Roberts 9 Posted September 19, 2018 Author Share Posted September 19, 2018 Thank you Brokenenglish . I appreciate you taking the time to post. I agree that it is very poor indeed for Ripmax to continue selling the model including instructions containing such a fundamental error. I am pretty sure I know the answer to my next question but I will ask it anyway - did Ripmax replace your lost Wot 4? Quote Link to comment Share on other sites More sharing options...
John Stainforth Posted September 19, 2018 Share Posted September 19, 2018 I had the same problem, and I added a little weight to the front. Without that the CG was too far back for my liking (even though I usually like my CGs fairly far back). Overall, I do not rate the model very highly for the price. Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted September 19, 2018 Share Posted September 19, 2018 Posted by John Roberts 9 on 19/09/2018 16:12:19: I am pretty sure I know the answer to my next question but I will ask it anyway - did Ripmax replace your lost Wot 4? I'm ashamed to admit that I didn't even ask, or even inform the seller (Inwoods), who give great service and it's not their fault. Furthermore, it's the second time that a gross kitting error by Ripmax has cost me a model. Quote Link to comment Share on other sites More sharing options...
Dave Hess Posted September 19, 2018 Share Posted September 19, 2018 I have one and use a 2200mAH 3S pack. Mine's the BNF one that comes with motor and servos so I didn't bother to measure the C of G. i just put my fingers under the wings about 1/3 of the way back to see if it was there or thereabouts, which it was. It flies perfectly. On low rates, it flies like a trainer, and on high rates it can fly a 10ft vertical square. I just measured it at 90mm from the leading edge. As a general fun plane, I think it's pretty good, but it could do with a bit more power and maybe a servo upgrade to unleash its full potential. Edited By Dave Hess on 19/09/2018 20:31:32 Quote Link to comment Share on other sites More sharing options...
John Roberts 9 Posted September 19, 2018 Author Share Posted September 19, 2018 Well I have now removed all the extra weight that I had painstakingly hidden within the tight confines of the cowl and the plane balances at the 80mm point. This ought to be a safe starting point given that Dave Hess' version flies well at 90mm. Just need a calm-ish day to get it maidened and trimmed out. For what it is worth I intend to take Ripmax to task about their failure to notify purchasers about the error in the manual. How hard can it be to put a note or sticker in/on the box? Relying on a statement on their web site just isn't good enough. Thanks to everyone above who responded to my post! Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted September 20, 2018 Share Posted September 20, 2018 Posted by John Roberts 9 on 19/09/2018 22:10:59: For what it is worth I intend to take Ripmax to task about their failure to notify purchasers about the error in the manual. How hard can it be to put a note or sticker in/on the box? Relying on a statement on their web site just isn't good enough. Thanks John, It's clearly unacceptable that Ripmax should consider that anyone buying, and then carefully assembling and flying a model, must consult their Web site to avoid a disaster. Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted September 20, 2018 Share Posted September 20, 2018 I had the same problem and it cost me a fuselage! I added weight to the front to get the CofG right as per the instructions, and it kept trying to dive into the ground. Whilst frantically reaching over to dial in a load of up trim, I managed to switch off the Tx!!! Being a computerised tranny, by the time it had come back up, the model was already in the deck! The replacement fuselage came with a sticker attached warning of the correct CofG which was spot on without any nose-weight! I'm not a fan of the model - the Foam-E version, anyway. Its OK for stick banging, but is divergent in pitch, presumably due to the VERY floppy tailplane. I bought it as a hack for testing suspect radio gear, but the radio compartment is too cramped for anything but the smallest of receivers. I won't be buying another when this one finally goes.... -- Pete Quote Link to comment Share on other sites More sharing options...
John Roberts 9 Posted September 20, 2018 Author Share Posted September 20, 2018 I have dropped a polite but forthright email to Ripmax regarding this issue. It will be interesting to see their response. Some on this forum have found Ripmax to be both quick & helpful when responding to queries/issues whereas others say they hear nothing. From time to time all companies will encounter faults with their products - the true measure of a good company is how they react & respond when it happens. Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 20, 2018 Share Posted September 20, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Mike T Posted September 20, 2018 Share Posted September 20, 2018 I don't usually do repeats but in the W4f-e's case, I'm on my fourth. The other 3 were lost to radio problems or excessive "exuberance"... All were assembled and flown out of the box - I didn't pay any attention to the CG as I was using the recommended battery size (3s 2200) and all the other gear was 'in situ'. All were slightly nose heavy requiring a little up trim - my latest more so as it has been 'up-gunned' with a 3542/1250 motor and 60A ESC. This required a little more up trim for it to fly S&L hands off. I've never had any pitch divergence issues. My tails have not been floppy, but they were/are all 'flexible'. The reinforcing spar does its job and the retaining screw must be well tightened. All used full-size JR (35) or FrSky receivers, which fitted snugly in the space provided. A more versatile model I've never had and I suspect its sales indicate many others think the same. That's not to excuse any failure to amend critical information, BTW, it's just that I never found it to be an issue. As usual, YMMV... Quote Link to comment Share on other sites More sharing options...
Mark a Posted September 20, 2018 Share Posted September 20, 2018 I don't think I even bothered to balance mine just chucked in the recommended battery and flew it trimmed it out and that was that, been my hack ever since. Quote Link to comment Share on other sites More sharing options...
Wilco Wingco Posted March 7, 2020 Share Posted March 7, 2020 Just bought one of these used from a fellow flyer for my grandson to learn on, with reduced throws of course. He has the c of g marked at 70 mm, the manual he gave me with the model, a MK 2, said c of g should be 60 mm?. All the references I have found so far say the manual states 70 mm but it should be 80 mm!. Help. Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted March 7, 2020 Share Posted March 7, 2020 The manual is WRONG! If you set it to 70mm, it will constantly try and dive into the deck (737 syndrome!). Mine flew fine with no ballast required, once I'd discovered this. Mine is now deceased following an unexpected diversion through a blinding sun, and I won't be replacing it! The very floppy tailplane made it divergent in pitch, which made it difficult to establish a correct trim. OK for stick banging, but not a nice flying machine. Glad to be shut of it! -- Pete Quote Link to comment Share on other sites More sharing options...
John Roberts 9 Posted March 7, 2020 Author Share Posted March 7, 2020 @Wilco Wingco Mine is set at 80mm and has now had hundreds of flights without incident so I would say it makes a safe & reliable starting point. The model does seems very tolerant of a wide range of CoG points and I have flown mine with it set as far back as 90mm (experimenting with prop hanging!) and as far forward as 70 mm (using an oversize battery) and, frankly, it didn't make a whole heap of difference. My advice is go for 80 or just a tad less and all should be well. I hope your grandson enjoys it because for such and cheerful foamy it is great fun and super value for money. Quote Link to comment Share on other sites More sharing options...
FlyinBrian Posted March 7, 2020 Share Posted March 7, 2020 Posted by Peter Christy on 07/03/2020 11:37:57: The manual is WRONG! If you set it to 70mm, it will constantly try and dive into the deck (737 syndrome!). Mine flew fine with no ballast required, once I'd discovered this. Mine is now deceased following an unexpected diversion through a blinding sun, and I won't be replacing it! The very floppy tailplane made it divergent in pitch, which made it difficult to establish a correct trim. OK for stick banging, but not a nice flying machine. Glad to be shut of it! -- Pete I totally agree re the floppy tailplane, I ended up framing the tail with hard 1/16 balsa and then filmed over it, its OK now. Quote Link to comment Share on other sites More sharing options...
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