Delta Foxtrot

Posted by Mark R on 10/12/2012 10:52:16: Well this is quality control on the wing brace.......hmmm has China been asked to make these parts? Probably not as their quality control is better..... Mine were the same. I emailed MHC and a few days later I got a replacement set, direct from SLEC. I also mentioned the lack of triangular balsa and was ent a a small piece, enough for the front fuselage, but not the turtle deck. At least MHC respond to these issues, hopefully the quality / content of the woodpacks will be improved for future buyers. Dave

Posted by david fillingham 1 on 01/12/2012 18:16:04: Posted by Nigel Hawes on 01/12/2012 06:30:26: David - 1/8 of an inch span loss is so negligible that you shouldn't worry. As for cutting the ailerons out before profiling, I'm not sure how you would get round that! I wasn't consulted on the CNC woodpack, nor have I seen one, so I can't really comment. Normally I'd advise you to spot glue the ailerons back in and then release them after profiling but if their outline has been CNC routed, then this won't be possible due to the routing gap. I imagine whoever designed the cut left them attached so they could be profiled BEFORE releasing, but if only small tabs have been left, then they'd probably break out anyway as the profiling stage involves quite rigorous planing and sanding. As a last resort you could make some new ailerons from some spare 10mm soft balsa sheet which are a very tight fit in their apertures, then as above, spot glue them in, profile the wing and release them at the end, shaving 1mm off each end for operating clearance. I'm sure over the course of this mass build some better solutions will be posted! Nigel, Thanks for your comments, it is good to get advice from the designer. I agree that the loss in span (1/4'' as both wings are 1/8'' short) is no big deal, but is annoying that laser cut parts should have such errors. I looked at more parts today and noticed some more minor problems. The dihedral braces are so badly cut they are scrap. The fuselage sides replicate an error on the plan, in that the top line is too high behind the cockpit, it would be good to confirm that the plan does have an error there. There is also no triangular stock in the woodpack. These are easily rectifiable and will hopefully be fixed for later copies. Thanks for the advice on the ailerons. I thought about tacking them back in with thin sheet to shim them into position and to support the ends. If this fails I will cut new parts and proceed as your build article. I think that the CNC parts should be modified to remove the aileron cuts for future copies. Thanks David I bult up the wings over the weekend and managed to profile the ailerons by chocking them in place with strips of balsa, which withstood razor planing and sanding. It is possible that the ailerons could be sucessfully profiled if they are not separated from the trailing edge pieces, but I think it would be better if the CNC parts were modified to remove the aileron cut. I mentioned my other points in an email to modelflying and today I received a replacement set of dihedral braces and a small amount of 10mm triangular stock. So 10/10 to modelflying for responding quickly to problems. I also had a defective canopy when I bought the plan and that was replaced quickly and without any fuss. The replacment wooden parts came from SLEC. David

Posted by Nigel Hawes on 01/12/2012 21:34:49: You can afford to use fairly firm leading edge panels, or as I've learned since I designed this model, a 3/16" dowel along the leading egde not only provides a uniform rounding, but also protects the panel, allowing the use of lighter balsa. I used this method on the subsequent Fizza and Whizzza designs with pleasing results. If you use firm leading edges, medium grade mainwing panels and soft trailing edges, you should end up with a very light and strong wing. Ironically one of my Tucanos was used to evaluate heavy loads for the cross-channel attempt, and even at 4 1/2 lbs weight, it still flew very nicely with loads more upward momentum for stall turns and reversals etc. So it is by no means a weight critical model, which takes the pressure off when trying to get the right balsa grades, something which is increasingly difficult these days! I used to make an annual 600-mile round trip to SLEC, spending whole days selecting the balsa for my kits and thoroughly getting in ian Hull's way I'm sure! Nigel, Nice to know that you do not consider the model to be to weight critical. My concerns about the woodpack gradings were based on reading your build articles, but I guess these were written nearly ten years ago. David

Posted by Phil Winks on 01/12/2012 17:35:33: David regarding profiling the ailerons now they're seperated how about using some good decoraters masking tape, wide stuff, underneath the wing to hold them in place while profiling this is usually done with the edge of the wing laid close to the edge of the bench and the wing flat on the bench so the tape underneath should keep the ailerons in place during the operation. Phil Thanks for the tip Phil, I will certainly try this. David

Posted by Nigel Hawes on 01/12/2012 06:30:26: David - 1/8 of an inch span loss is so negligible that you shouldn't worry. As for cutting the ailerons out before profiling, I'm not sure how you would get round that! I wasn't consulted on the CNC woodpack, nor have I seen one, so I can't really comment. Normally I'd advise you to spot glue the ailerons back in and then release them after profiling but if their outline has been CNC routed, then this won't be possible due to the routing gap. I imagine whoever designed the cut left them attached so they could be profiled BEFORE releasing, but if only small tabs have been left, then they'd probably break out anyway as the profiling stage involves quite rigorous planing and sanding. As a last resort you could make some new ailerons from some spare 10mm soft balsa sheet which are a very tight fit in their apertures, then as above, spot glue them in, profile the wing and release them at the end, shaving 1mm off each end for operating clearance. I'm sure over the course of this mass build some better solutions will be posted! Nigel, Thanks for your comments, it is good to get advice from the designer. I agree that the loss in span (1/4'' as both wings are 1/8'' short) is no big deal, but is annoying that laser cut parts should have such errors. I looked at more parts today and noticed some more minor problems. The dihedral braces are so badly cut they are scrap. The fuselage sides replicate an error on the plan, in that the top line is too high behind the cockpit, it would be good to confirm that the plan does have an error there. There is also no triangular stock in the woodpack. These are easily rectifiable and will hopefully be fixed for later copies. Thanks for the advice on the ailerons. I thought about tacking them back in with thin sheet to shim them into position and to support the ends. If this fails I will cut new parts and proceed as your build article. I think that the CNC parts should be modified to remove the aileron cuts for future copies. Thanks David

I have just recieved my cnc and additional woodpack today. It looks like the wing leading and trailing edge pieces are 1/8'' short when laid over the plan. I wondered if anyone else has noticed this? I could either reduce the centre section by 1/8'' and lose 1/4 '' of wing span or add some 1/8'' strips to the leading and trailing edge pieces at the wing root. I am reluctant to loose wing span as the wood selection in the pack does not look great and the airframe weight might be a little higher than optimum. I parted the aileron from the trailing edge as these were joined by a few small spurs of balsa. After laying the parts over the plan I wondered how to plane the wing and aileron to the required wing section. Nigel Hawes instructions do not cut out the ailerons form the wing until after profiling. I would be interested if anyone has any views on how to solve these issues.

Please count me in. Thanks

Just to round off I have flown my replacement acro wot foam e loads since I lost the first one to the esc failure. It is a great aeroplane for the price, it flies very well and I have had loads of fun with this. It is still going strong after 160 + flights.

My copy of the plan arrived this morning, so I am in.

Posted by MZH on 07/07/2012 23:29:49: Hi after flying the wot4 foam-e with no problems apart from pilot error ,I purchased a acro wot foam-e. like other struggled to get the battery in and fit the cover not a quick job. (what is the mod with regards to the battery compartment to improve acess?) nice calm day ,first flight all trimmed out very nicelty But on a couple of occasions ,just as if you had totally lost all power motor and radio for a second then ok, same again on landing approach. checked all connection all seems ok, phoned the model shop that I purchased it from and theer suggestion was to change the esc (skywalker esc as supplied) with the on from my wot for and try again. have yet to try MZH The battery access mod is on the Ripmax website **LINK**.

I flew another six flights with the Acro wot foam e tonight and on one flight I heard a vibration so I cut it short and landed to investigate. The motor was very warm, but the ESC was just a little warm. The problem was caused by the battery cables / connectors rubbing against ths outrunner. I have incorporated the Ripmax ESC positioning mod, but with some of my 3S / 2200 Mah batteries it is still a bit of a squeeze getting the cables in and the hatch on. Next flight the motor was down on power so I landed to let it cool and all seemed well on the last flight. It seems very likely that the ESC on my first Acro Wot, which was close coupled behind the motor due to the poor installation on manufacture, failed due to rubbing against the motor. I will be more vigilant with the battery wires on future flights. I am just posting this in case helps prevent others experiencing similar problems. Dave F

Update on my ACRO WOT Foam e problem. I returned the model to Kings Lynn who were very helpful and quickly sent it back to Ripmax. Ripmax sent me a replacement which was not of as good quality as the first aeroplane. There were had a blemishes around the cockpit area and on the tail, but I managed to cover most of these with the stickers. I could not be bothered to send it back to Ripmax as they would not cover the postage costs of returning the original. I emodied the ESC positioning mod suggested by Ripmax, which makes battery positioning easier, but does nothing for ESC cooling. I do not think lack of ventilation was the problem I had with the first model, I believe it was a faulty ESC as it was cool after the first two flights, but burning hot within seconds of connecting the batter to the ESC after the crash. I flew it for the first time tonight. Six short flights pf around 5 mins. I gradually used more throttle on each flight and had no problem with the ESC, it was only slightly warm at the end of the session. Hopefully the ESC problem I had was down to a faulty unit. Dave F

Update on my ACRO WOT Foam e problem. I returned the model to Kings Lynn who were very helpful and quickly sent it back to Ripmax. Ripmax sent me a replacement which was not of as good quality as the first aeroplane. There were had a blemishes around the cockpit area and on the tail, but I managed to cover most of these with the stickers. I could not be bothered to send it back to Ripmax as they would not cover the postage costs of returning the original. I emodied the ESC positioning mod suggested by Ripmax, which makes battery positioning easier, but does nothing for ESC cooling. I do not think lack of ventilation was the problem I had with the first model, I believe it was a faulty ESC as it was cool after the first two flights, but burning hot within seconds of connecting the batter to the ESC after the crash. I flew it for the first time tonight. Six short flights pf around 5 mins. I gradually used more throttle on each flight and had no problem with the ESC, it was only slightly warm at the end of the session. Hopefully the ESC problem I had was down to a faulty unit. Dave F

I have copied a posting in another thread that I started, not realising this one was around. Just thought people here might like to know about this. Hi, I took delivery of the new Acro Wot Foam e last week, tonight was the first opportunity to test fly it. I had two 5 minute flights at moderate throttle setting aimed at trimming the aircraft and flying gentle circuits. The aircraft flew well and I started to feel like I had made a good purchase. On the third flight I was making a gentle descending turn when at around 100 ft I lost all control of the model, no response! I retrieved the model from a cornfield where it nosed in and split split the nose open. There was a strong smell coming from the ESC which was still hot to the touch after a 4 or 5 min walk back to the benches. The model came with a 40 amp ESC and I measured 300 w / 30 amps at full throttle before flying it, so on paper the ESC should have had some margin, but in flight it failed without prolonged running at anywhere near full throttle. I plan to contact Kings Lynn models to try and get this rectified, but I am dubious about accepting a replacement model given, the saga of the WOT 4 foam e ESC problems. I would be interested to hear from anyone else who has had a similar problem with this model. dave f

Posted by Peter Beeney on 18/06/2012 20:38:20: David, - This happened to me, on a beginners, (a youngster), model that he was learning to fly with. On take off, as it happens, this one came down with loss of control and with the ESC really well alight, flames spurting out. Not on the third flight, but not long after. His father contacted Ripmax direct and they replaced it instantly. Dad repaired the damage and the second one has been going strong ever since. It’s certainly been broken again, and repaired, once or three times or more but the accidents are now getting very infrequent. I think it is a well known problem, so I would say that any replacement will be fine. Good Luck. PB Peter, Thanks for the feedback. I have emailed Kings Lynn, but I will take your advice and contact Ripmax if that doesn't work. dave

The kit quality was general OK. The fin and rudder hinges were showing daylight so I used glass fibre tape to reinforce these as I have done on the WOT 4 foam e. The stickers are very sticky and I would advise not fully peeling off the backing when applying. Just peel off the edges and smooth on progresively. The outer part of the elevator snake was protruding too much and limited down elevator movement. It is simple enough to remove the control rod and trim it off. Generally the quality was similar to the WOT 4 foam e with perhaps a few early production areas that could be improved. The other issue I noted was that the ESC cables where cable tied to both sides of the engine mount. This meant that the ESC had to be positioned just below the motor which I thought might potentially be a problem. This does position the ESC in the cowl vent flow so I decided to fly it as suppied. I doubt that this was a contributary factor to the overheating as the motor was only slightly warm to the touch, but the ESC was too hot to handle. I had to trim it with a bit od down elevator to stop it climbing. I had a 3s 2200 mAh pack sat where it should be and the CoG was just a little forward of the position recomended, perhaps it needs a small amount of weight in the nose, but it was not a big issue. hope this helps dave

Hi, I took delivery of the new Acro Wot Foam e last week, tonight was the first opportunity to test fly it. I had two 5 minute flights at moderate throttle setting aimed at trimming the aircraft and flying gentle circuits. The aircraft flew well and I started to feel like I had made a good purchase. On the third flight I was making a gentle descending turn when at around 100 ft I lost all control of the model, no response! I retrieved the model from a cornfield where it nosed in and split split the nose open. There was a strong smell coming from the ESC which was still hot to the touch after a 4 or 5 min walk back to the benches. The model came with a 40 amp ESC and I measured 300 w / 30 amps at full throttle before flying it, so on paper the ESC should have had some margin, but in flight it failed without prolonged running at anywhere near full throttle. I plan to contact Kings Lynn models to try and get this rectified, but I am dubious about accepting a replacement model given, the saga of the WOT 4 foam e ESC problems. I would be interested to hear from anyone else who has had a similar problem with this model. dave f