FEDERICO GILLI Posted October 9, 2009 Share Posted October 9, 2009 As I cannot find any building blogs on the new Seagull Percival Mew Gull I decided to start my own one, please feed in any comment or suggestion, all is welcome. I’ve been looking at this model since the add’s start populating the magazines and eventually I pulled out the finger and order one for myself! The big colour full box arrived in good conditions and all the items, most still packed, appear to be fine. The first thing you see is a very large fuselage and already fitted pilot. The last item appear to be very big but if compared to the real size aeroplane it is not. The pre fitted canopy is properly secured with both glue and screw. I would have preferred to be able to add few extra cockpit details and more accurate instrument panel without having to risk damage the canopy but I’ll worry about it in due course. The fuselage is very well covered including the wing fairings that are wooden build up structures rather than ABS attachment. The large fibreglass cowl is very well painted and the light cream colour is just a tad darker than the profilm used to cover the balsa and plywood structures. A nice silver stripe is painted on top of the cowl as per the real prototype. Seagull did a good job in going for silver paint instead a much easier sticker. The two wings and tail plane half look small in comparison to the fuselage but I guess this is only an impression as with almost 1.9m of wing span the model is not small at all. The fin and rudder is pre installed in the fuselage top tail cone attachment. In this unit a couple of plywood tabs are designed to add strength to the epoxy bond once fitted to the fuselage. Reading at David’s Sparrow hawk review this looks to be an improvement as the lack of such was pointed out. One other obvious difference is that the two elevator servos are fitted under the canopy rather than at the tail end leaving a cleaner and more scale-ish look. The well spats are well made, some work need to be added to modify the front section to match the real units, this mod will also improve the long grass handling as more of the wells will be uncovered. Aluminium spars are supplied for both main and tail wings. Considering the size of the model I would have liked to be able to transport the wing in two half but this is not an option, good job I’ve a station wagon. The wheels are big foamy jobs, so providing the grass is not too long should not create any trouble. The oleo struts are supplied but they do not look exactly as the units on magazine pictures, the lovely aluminium support have been replaced with standard Z shaped thick piano wire. After months of deliberation I decided to go petrol for this one. This is my first spark engine and I thought to go for a Chinese job to save few bobs. Eventually once I got the model I could not face to butcher the cowl to accommodate carburettor and exhaust so I finished off in buying one of the most expensive 25cc on the market with optional inverted pit muffler! I got a Roto 25 and I put it in “investment for the future” light! The unit arrived from the factory un-scratch and as you can see from the picture is quite a piece of kit. I have to say that the size of the Roto 25 is quite intimidating as my biggest engine till date was an OS 70fl. The grp motor supports supplied with the kit are just big enough but since they were suppose to harness the power of a 1.20 2 stroke I hope they will be strong enough for the 25 petrol. That’s for now. Regards, > > Federico Quote Link to comment Share on other sites More sharing options... Advert Stephen Grigg Posted October 9, 2009 Share Posted October 9, 2009 Lpooking forward to this build Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 9, 2009 Author Share Posted October 9, 2009 Start opening the different plastic bag I found the fuel tank. The supplied item is 400cc. Despite this will be the best fit for the built in plywood frames I’ve decided to go for a 300cc unit with the hope to save a bit of weight in light of the petrol engine low consumption and extra weigh at the front. I’ll use the bung I got a wile back for a Sullivan tank that looks fitting ok. On the weight issue David had to put some lead in the nose so I’m hoping that the model will not require to be counterbalanced on the tail once complete. Probably tail mounted servos will have helped here. Speaking of the servos having overspent on the engine I start looking around for cheap high torque standard size units. This is never a good idea but I decided to have a go at some spingrc units I found on the net. They appear to have been successfully used in large petrol 3D planes so I though to have a go. I’ll install them in my faith-full (and disposable) new yamamoto for a wile to be sure to be sure. As per the receiver I have not decided yet. As 35Mhz futaba man I should look for a decent PCM unit, said that my only futaba rx are in my two 50 size helis and non is PCM. Most of my glow planes have 8ch corona’s units both synthesised and non. I have to say that I’m very impress by these little fellas and I never got any trouble from them at all. One other nice bit is the aluminium backed spinner. This one has already found a new home in my VQ Macchi 205 so I’m planning to go for a same size full aluminium unit for the Mew gull. For completeness I can only add that I did stick a bit of duck tape to the back-plate to get the balance right. lace w:st="on">Batterylace> wise I’ll use a 4.8V 2200mA on the engine electronic and probably the same for the servos. For the electric enthusiast the kit come with a substantial conversion kit that will accommodate any type of set up you will choose. The kit is completed with a neat battery hatch with two spring loaded catches and required minimum modification to the front of the fuselage and cowl. Regards, > > Federico Quote Link to comment Share on other sites More sharing options... Kelly Posted October 10, 2009 Share Posted October 10, 2009 Hi Federico, Very nice looking model . I look forward to the rest of your build and maiden flight Kelvin Quote Link to comment Share on other sites More sharing options... Former Member Posted October 10, 2009 Share Posted October 10, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 12, 2009 Author Share Posted October 12, 2009 Hi Polyphilla, I've try few time the paste from word icon but I could not get it to work. As I've not much time to type stuff during the day and I not reliable internet at home I use word at home and past from work. I've also try to paste as plain text with the same result. Probabily is me! Regards, Federico Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 13, 2009 Author Share Posted October 13, 2009 Last night I start measuring up for the engine installation. Firs job was to remove the captive nuts from the 8 o’clock engine installation. The captive nuts look like glued and I thought I was in for a fight but a 4mm bolt and few tap with the hammer and the job was done. The glue was only external to them so no major surgery required.As the firewall is already drilled for the electrical conversion I tried to fit the engine mounts at this location. The first impression was good but after a more accurate examination the engine centre line was a bit too high. As per the attached picture the centreline for the electric motor (marked with E) is way different that the one for the IC engine (marked with P). I can’t understand why the two don’t match so if anyone has an idea please do not be shay!With the help of a Mr Sheen can I tried to align the cowl and firewall centre line and the result is that the electric conversion CL is lining up pretty well with the cowl hole.Unless the trust line is different from IC to electric I can’t see why the two aren’t matching. I do not think as well that the orientation of the engine will make any difference.To cut the story short I decided to use the electric motor mounting holes to support the two engine supports. The engine resulting position is 3-4 mm to high so instead of drilling a third sets of holes in the firewall with the result of having a flying Swiss cheese I decided to use shims between the engine and the mounting blocks to align the engine the CL. PTFE or metal strips will be used as shims.One other thing I have to do on the engine installation is to beef up the firewall joints to the fuselage structure. The latest is build in two layers both glued to the firewall. The external layer is the fuselage external sheeting while the internal is a light balsa frame. As the external one is not accessible I will add some triangular stock to the join to the plywood structure using epoxy glue. The firewall itself is circa 1cm thick and unless advised differently I take is good enough for the 25cc. I have no idea if the firewall need to be fuel proofed as I will use petrol but I will do it anyway for good measure.That’s it for now.Regards, Federico apologies for any smily faces but the paste from word function does not work at all on my pc. Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 16, 2009 Author Share Posted October 16, 2009 Next step is getting all the bits together and start mounting the engine. The two engine mounts are just 4mm too short so the exhaust does not clear the firewall. Two pieces of good plywood will sort this out. The 3mm PTFE spacers looks thick enough to get the shaft centre line in the electric motor required position and everything line up with the cowl opening. I’m still very puzzled about the I/C engine shaft centreline position on the firewall. As no mention is made on the instruction I’ll not going to add any more trust angle to the motor installation. The fire wall had already a bit of right-down trust build in it so I’ll take is a good enough starting point. I’ll have the first few flights without cowl. This will facilitate engine set up and help in keeping an eye on the front end installation. If I’ll need to add washers to get a better thrust line not having fitted the cowl yet will avoid having to drill more holes in the fuselage to get the alignment right again. I’ll get the motor installation sorted and than I’ll put it aside until the firewall fuel proofing and strengthening are done. I’ll pick up some thin Zap at the weekend so I’ll be able to start fitting all the hinges and move on to the rest of the assembly. Quote Link to comment Share on other sites More sharing options... Jack Rogerson Posted October 16, 2009 Share Posted October 16, 2009 Hi Frederico, A couple of guys in our club built Mew Gulls many years ago, and they suffered from aileron vibration. Our answer was to fit balance weights to the ailerons, and increase the diameter of the torque rods from the centrally-mounted servo. People didn't use separate servos at the time, too expensive. Hope your one doesn't suffer from the same problem. Stackerjack. Quote Link to comment Share on other sites More sharing options... Stephen Grigg Posted October 17, 2009 Share Posted October 17, 2009 Ive always found Seagull seem to sort there models out before producing them so hopefully that fault will have been cured Quote Link to comment Share on other sites More sharing options... Les Holloway Posted October 17, 2009 Share Posted October 17, 2009 Federico - I'm also assembling a Seagull Mew Gull, and have so far completed the wing and u/c assembly without problems, However, I have hit a real difficulty with my engine installation. I am using a Laser 150 four-stroke, mainly because fully inverted it will fit wholly inside the cowl without any nasty protrusions, and with the exhaust pointing straight down out of the cooling vent which I shall cut in the bottom of the cowl Like you, I was puzzled by the different thrust lines, but I took the angled-two-stroke with pre-fitted captive bolts as the definitive position, and drilled new holes to get my thrust line in exactly the same place. Because of the length of the Laser's bearers I had to fit a standoff to get the right position. I now find that when the cowl is sitting neatly on top of the fuselage, the engine is about 4mm too low, so the spinner does not line up properly. If I tilt the cowl down, the alignment is better, but then the rear end of the cowl is 2 or 3 mm above the fus - spoiling the look. My dilemma is: do I accept that the cowl is not accurate, and bodge it as best I can - or do I raise the engine 4mm to line up with the "best position" cowl, and risk the thrust line being out? I've emailed Seagull and Perkins for advice and await their replies, but if anyone has any thoughts I'd be grateful to hear them. Cheers - Les Holloway Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 19, 2009 Author Share Posted October 19, 2009 Hi Stakerjack, The model come with one servo per airelon. This combined with high torque units coupled with thick adjustable metal rod should fix the issue. Thanks for the heads-up. Regards, Federico Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 19, 2009 Author Share Posted October 19, 2009 Hi Les, I'm glad you are working on the same project! Information sharing could potentially save us some hassle. For the engine installation I adopted the opposite solution going for the electrical option thrust line. The only reason was that this position was aligning perfectly with the cowl front hole. The other thing I considered was that not having to drill an other series of holes would have give me the option to find a better location after if things are not working ok. Can you tell me if you choose to beef up the fire wall in any way? Did you also used the supplied hinges or did you replaced them with different units? I could not get my hand on the Zap and triangular balsa stock a the week end so I have no building news to report. Regards, Federico Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 19, 2009 Author Share Posted October 19, 2009 I have a question about cowl vents and air intakes. As the real thing has a quite large air intake below the propeller I will replicate the same on the model without spoiling the look. From a vent point of view thing are a bit more complicate. My plan of action is to replicate the right side louver plate as per original. I've aluminium and a brass plates and I was planning to use some for this poupose. The brass is thinner but I guess the aluminium is easier to cut. I was thinking to use a large wood chisel to open up the louvers. Suggestions? I do not think that the louvers on the right side will be sufficient to expel all the air coming from the intake, for this reason I'll drill out the 6 exhaust holes on the bottom of the cowl too. Regards, Federico Quote Link to comment Share on other sites More sharing options... Les Holloway Posted October 19, 2009 Share Posted October 19, 2009 Hi Federico - I didn't beef up the firewall, mainly because when I peered inside the fus there was a substantial glue fillet all around the firewall joint. I also used the supplied hinges as I have never had a problem with these 'fuzzy mylar' types, even unpinned. In this case, to be on the safe side, cocktail-stick pins will be inserted from the underside. Like you, I am planning to replicate the right side louvre in very thin aluminium, but not as a functional item. Haven't yet worked out how I am going to cut the louvres! As I need access to my Laser carb and plug from below, I need a fairly large vent in the bottom of the cowl. I shall try to make the front cut-out match the one on the full-size. I also intend to make internal baffles to direct incoming air over the cylinder head. Regarding my engine / cowl alignment problem, I have now had a reply from Perkins, who say their demo Mew Gull also needed the cowl tilted slightly down to line up with the spinner. However, they also say that moving the engine a few mm upwards should not affect the flying performance. Meanwhile Seagull in Vietnam have passed on my enquiry to someone who sounds American - may even be the designer... I await his comments with interest. Cheers - Les Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 20, 2009 Author Share Posted October 20, 2009 Hi Les, you are right about the glue around the firewall but in my one is just about visible. I'll add some extra epoxy and balsa fillets for good measue as I'm not familtiar with pertol engine vibration levels. I got some zap this morning so I'll try the mylar hinges tonight. I'm still short of few bits but as I'm drivig to Belfast at the week end I hope to find what I need there. I'm very courious to see the replay from seagull about the thrust line. I was looking at the instruction manual and the electric conversion firewall look different from the one in my kit. In the manual the firewall thrustline line-up with the one on the main firewall while in the kit does not. As per the Perkins guy I think that down and right thrust are more important than keeping the centre line of the engine on the plane datum line. Anyway I do not even know if the lower position achieve this objective. If you have any pictures of your plane please do post them in this thread. Regards, Federico Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 21, 2009 Author Share Posted October 21, 2009 Got the Zap! I've got all hinges sorted in wings and elevator halves as per instruction but I did not agreed with the fin/rudder hing installation before fitting the fion the fuse. I glued the fin assembly to the fuselage with 5 min epoxy after removing the cover film as per instructions. I also remove the film from the bottom tail cone gluing area. I try the tail wheel assembly and discover than the wheel rudder shaft did not sit parallel to the fin/rudder at all. This potentially will introduce strain on the hinges. I fix this adding two washer below the back screw on the tail assembly. By the way the instruction call for three screws to retain the wheel but only two holes are present. Despite the shaft now lineing up there still a bit of side movment on the wheel shaft when the rudder move. would have prefered a different system similar to the sparrowhawk to reduce the strain on the rudder hinges. Before getting at the tail I tryed to add epoxy and a couple of balsa filletts on the inside of the firewall. This prove to be a hell of a job as the acess to the area will be an issue for an Hobbit! I managed anyhow to get some of the planned work done. Water based dulux diamond coat wood varnish was used to fuel proof the fire wall and tank bay, again the last item was a nightmare to reach so do not know how well the job turned out. Overall I'm quite pleased the only snag is that after I got the rudder glued to the fin I noticed that the alignment of the two is not perfet as the rudder top is slightly out on the right side. As this is a minor issue it is probabilbetter to stick with it rather than tamper with the hinges increasing the risk of less than secure bonding. That's all folks!! Regards, Federico Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 23, 2009 Author Share Posted October 23, 2009 Hi, I've started looking in the tail plane halves set up. The instruction are calling for two 7cm long 3mm OD steel rods. This two items as the main aluminium brace tube, shall be fed through the pre drilled holes below the fin assembly. The main brace tube is a perfect fit and match both fin and tail plane halves just righ. Not the same can be said for the two steel rods, these item are not 3mm but 2.5ish. Once you slide them in the receptacle holes they are completely loose. I decided to ditch the two and replace them with 3mm brass rods cutted from a welding rod. The fit is now perfect and I'll soon epoxy them in place before I do the same with the elevators halves. The more I look into the wing/tail design the more I'm convinced that Segull with very little extra efford coul have provide the existing set-up with grub srew retainers allowing the dimantle of both main wing and tailplane for easier transportation. Regards, Federico Quote Link to comment Share on other sites More sharing options... Peter 'Ivanna Crashalot' Savage Posted October 24, 2009 Share Posted October 24, 2009 It is a very nice aircraft! Dad's got a seagull EP Decathlon, it was quite well constructed. Offtopic: My grandad worked at percivals after the war, think the mew gull was before the war and the original G-AEXF is at RAF hendon in london Edit: it is a replica at hendon, the real one is in yorkshireEdited By Peter Savage on 24/10/2009 21:13:38 Quote Link to comment Share on other sites More sharing options... Les Holloway Posted October 27, 2009 Share Posted October 27, 2009 Hi Federico - You're right about the transportation issues. I keep looking at that six-foot wing, complete with undercarriage, hanging in the rafters of my workshop, and wondering how I am going to fit it into my modest hatchback! I also share your thoughts on the tailplane fixing, although I've done mine mainly by the book' and it all went together very nicely. I had my doubts about the whole of the tail feather assembly being held in place by a relatively narrow glue bond, so I increased the surface area by building up with thin ply in strategic places, and used 30-min epoxy. As far as the two locating wires for the tail plane halves are concerned, mine are also short, but as they are only going into a single rib I don't think that matters, I cyanoed them in place in the fin base before sliding on the tailplane halves on the main brace tube, using 30-min epoxy again. Still haven't heard from the Seagull guy about my engine alignment issue... Hi Peter -You've presumably found the RAF Museum website which gives you a 3D view of both the replica Mew Gull at Hendon and an internal full panorama of the cockpit, and also the stuff at the Real Aeroplane Company at Breighton Aerodrome, where the real one is based. There are quite a lot of nice pix of G-AEXF on the JetPhotos.Net website. Cheers - Les Quote Link to comment Share on other sites More sharing options... Graham Ashby (Editor) Posted October 28, 2009 Share Posted October 28, 2009 Interesting to read your comments guys. Short of adding the stickers my Mew Gull is practically ready to fly. I too had the same issue with the cowl, engine thrust line and spinner / nose ring relationship but opted to leave the set-up alone as I'm duty bound to put the model together 'as is', it being a review an' all. Mind you, I'm not too distressed about the appearance of the cowl. It'll be interesting to see if anyone at the club notices. Agree that the cockpit is bland, though I plan to remove the canopy very shortly after the review's put to bed and do something with it, i.e. extend the dash further into the cockpit as a continuation of the forward fuselage decking, add a better instrument panel, and fit a 1/4 scale latex pilot. I'm tempted to add a pitot tube and a few panel lines, too. Engine: Saito 150 installed as per kit with the exhaust exiting on the underside. Had I been building it entirely for myself I'd have fitted it inverted and fully cowled. Has anyone heard any comments about how the model flies? I'm getting close enough to the test flight to be very interested. Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 30, 2009 Author Share Posted October 30, 2009 Les, Graham, would you be so kind to tell me your servo choice for the Mew Gull? Regards, Federico Quote Link to comment Share on other sites More sharing options... Graham Ashby (Editor) Posted October 30, 2009 Share Posted October 30, 2009 Yes, I'm using six SuperTec S03T / 2BB servos - 5.8kg-cm torque but noticeably slow, not that speed is much of an issue in this instance! Quote Link to comment Share on other sites More sharing options... FEDERICO GILLI Posted October 30, 2009 Author Share Posted October 30, 2009 Thanks Graham, I got my box of outstanding bits last night. The hawk wooden prop 18x10 look impressive and it is probabily the closest thing to scale I can fit in an I/C non geared set up! The prop appear to have enough meath around the shaft to allow for the multi bolt roto prop hub. So I need to drill the prop next. On this I've planned to use only 2 of the 4 bolts supplied I hope this will be sufficent. Shall I drill the prop perpendicular to the blades or in line with them? The alluminium spinner I ordered look nice too but I'll tell you more after I balace it. I also got an heavy duty CRRC power switch complete with led and charge socket to be used as supply / kill switch to the injection system. I'll use a standatd switch for rx and servos. Speaking of servos I got my 9kg MG Spring-rc servos. They looks good and have been supply with a substantial array of arms. I need to set them up into my new yamamoto to check them in the air. As the loads in the Mew Gull are not goint to be huge I hope they will work fine. Some 6x3mm pertol fuel tube was part of the order so I can now fit the tank. As I have a number of different commecial glow inline filters I was wandering if I can use any of them with petrol. Any suggestion on this? Thanks a million. Regards, Federico Quote Link to comment Share on other sites More sharing options... Les Holloway Posted October 30, 2009 Share Posted October 30, 2009 Hi everyone – Re servos – I’m using Hitec HS-5625MG digitals – 9.45 Kg.cm torque on the 6v battery I’ve installed. That’s probably overkill for this model, but I was thinking ahead to a large aerobatic machine… Here are some pix of my cowl problem – sorry about the crap photography – cramped workshop and I’m still experimenting with a new camera. 1 The Laser 150 installed on what I reckon is the right thrustline: 2 The best cowl fit I can get with the engine in that position: 3 Not too bad, you might think – but this is what the back end of the cowl looks like: 4 And if I get the cowl to sit properly on the fus, this is what happens at the front end: That’s really not acceptable, so I reckon I am going to shift the engine 3mm or so higher and hope that the altered thrust line is not going to affect the flight performance too much… Graham – I’m really looking forward to your review! Cheers - LesEdited By Les Holloway on 30/10/2009 13:44:24 Quote Link to comment Share on other sites More sharing options... Prev 1 2 3 4 5 6 Next Page 1 of 12 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply Share More sharing options... Followers 0 Go to topic listing Latest Posts Home THE WORKSHOP Build Blogs and Kit Reviews Percival Mew Gull × Existing user? 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Stephen Grigg Posted October 9, 2009 Share Posted October 9, 2009 Lpooking forward to this build Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 9, 2009 Author Share Posted October 9, 2009 Start opening the different plastic bag I found the fuel tank. The supplied item is 400cc. Despite this will be the best fit for the built in plywood frames I’ve decided to go for a 300cc unit with the hope to save a bit of weight in light of the petrol engine low consumption and extra weigh at the front. I’ll use the bung I got a wile back for a Sullivan tank that looks fitting ok. On the weight issue David had to put some lead in the nose so I’m hoping that the model will not require to be counterbalanced on the tail once complete. Probably tail mounted servos will have helped here. Speaking of the servos having overspent on the engine I start looking around for cheap high torque standard size units. This is never a good idea but I decided to have a go at some spingrc units I found on the net. They appear to have been successfully used in large petrol 3D planes so I though to have a go. I’ll install them in my faith-full (and disposable) new yamamoto for a wile to be sure to be sure. As per the receiver I have not decided yet. As 35Mhz futaba man I should look for a decent PCM unit, said that my only futaba rx are in my two 50 size helis and non is PCM. Most of my glow planes have 8ch corona’s units both synthesised and non. I have to say that I’m very impress by these little fellas and I never got any trouble from them at all. One other nice bit is the aluminium backed spinner. This one has already found a new home in my VQ Macchi 205 so I’m planning to go for a same size full aluminium unit for the Mew gull. For completeness I can only add that I did stick a bit of duck tape to the back-plate to get the balance right. lace w:st="on">Batterylace> wise I’ll use a 4.8V 2200mA on the engine electronic and probably the same for the servos. For the electric enthusiast the kit come with a substantial conversion kit that will accommodate any type of set up you will choose. The kit is completed with a neat battery hatch with two spring loaded catches and required minimum modification to the front of the fuselage and cowl. Regards, > > Federico Quote Link to comment Share on other sites More sharing options...
Kelly Posted October 10, 2009 Share Posted October 10, 2009 Hi Federico, Very nice looking model . I look forward to the rest of your build and maiden flight Kelvin Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 10, 2009 Share Posted October 10, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 12, 2009 Author Share Posted October 12, 2009 Hi Polyphilla, I've try few time the paste from word icon but I could not get it to work. As I've not much time to type stuff during the day and I not reliable internet at home I use word at home and past from work. I've also try to paste as plain text with the same result. Probabily is me! Regards, Federico Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 13, 2009 Author Share Posted October 13, 2009 Last night I start measuring up for the engine installation. Firs job was to remove the captive nuts from the 8 o’clock engine installation. The captive nuts look like glued and I thought I was in for a fight but a 4mm bolt and few tap with the hammer and the job was done. The glue was only external to them so no major surgery required.As the firewall is already drilled for the electrical conversion I tried to fit the engine mounts at this location. The first impression was good but after a more accurate examination the engine centre line was a bit too high. As per the attached picture the centreline for the electric motor (marked with E) is way different that the one for the IC engine (marked with P). I can’t understand why the two don’t match so if anyone has an idea please do not be shay!With the help of a Mr Sheen can I tried to align the cowl and firewall centre line and the result is that the electric conversion CL is lining up pretty well with the cowl hole.Unless the trust line is different from IC to electric I can’t see why the two aren’t matching. I do not think as well that the orientation of the engine will make any difference.To cut the story short I decided to use the electric motor mounting holes to support the two engine supports. The engine resulting position is 3-4 mm to high so instead of drilling a third sets of holes in the firewall with the result of having a flying Swiss cheese I decided to use shims between the engine and the mounting blocks to align the engine the CL. PTFE or metal strips will be used as shims.One other thing I have to do on the engine installation is to beef up the firewall joints to the fuselage structure. The latest is build in two layers both glued to the firewall. The external layer is the fuselage external sheeting while the internal is a light balsa frame. As the external one is not accessible I will add some triangular stock to the join to the plywood structure using epoxy glue. The firewall itself is circa 1cm thick and unless advised differently I take is good enough for the 25cc. I have no idea if the firewall need to be fuel proofed as I will use petrol but I will do it anyway for good measure.That’s it for now.Regards, Federico apologies for any smily faces but the paste from word function does not work at all on my pc. Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 16, 2009 Author Share Posted October 16, 2009 Next step is getting all the bits together and start mounting the engine. The two engine mounts are just 4mm too short so the exhaust does not clear the firewall. Two pieces of good plywood will sort this out. The 3mm PTFE spacers looks thick enough to get the shaft centre line in the electric motor required position and everything line up with the cowl opening. I’m still very puzzled about the I/C engine shaft centreline position on the firewall. As no mention is made on the instruction I’ll not going to add any more trust angle to the motor installation. The fire wall had already a bit of right-down trust build in it so I’ll take is a good enough starting point. I’ll have the first few flights without cowl. This will facilitate engine set up and help in keeping an eye on the front end installation. If I’ll need to add washers to get a better thrust line not having fitted the cowl yet will avoid having to drill more holes in the fuselage to get the alignment right again. I’ll get the motor installation sorted and than I’ll put it aside until the firewall fuel proofing and strengthening are done. I’ll pick up some thin Zap at the weekend so I’ll be able to start fitting all the hinges and move on to the rest of the assembly. Quote Link to comment Share on other sites More sharing options...
Jack Rogerson Posted October 16, 2009 Share Posted October 16, 2009 Hi Frederico, A couple of guys in our club built Mew Gulls many years ago, and they suffered from aileron vibration. Our answer was to fit balance weights to the ailerons, and increase the diameter of the torque rods from the centrally-mounted servo. People didn't use separate servos at the time, too expensive. Hope your one doesn't suffer from the same problem. Stackerjack. Quote Link to comment Share on other sites More sharing options...
Stephen Grigg Posted October 17, 2009 Share Posted October 17, 2009 Ive always found Seagull seem to sort there models out before producing them so hopefully that fault will have been cured Quote Link to comment Share on other sites More sharing options...
Les Holloway Posted October 17, 2009 Share Posted October 17, 2009 Federico - I'm also assembling a Seagull Mew Gull, and have so far completed the wing and u/c assembly without problems, However, I have hit a real difficulty with my engine installation. I am using a Laser 150 four-stroke, mainly because fully inverted it will fit wholly inside the cowl without any nasty protrusions, and with the exhaust pointing straight down out of the cooling vent which I shall cut in the bottom of the cowl Like you, I was puzzled by the different thrust lines, but I took the angled-two-stroke with pre-fitted captive bolts as the definitive position, and drilled new holes to get my thrust line in exactly the same place. Because of the length of the Laser's bearers I had to fit a standoff to get the right position. I now find that when the cowl is sitting neatly on top of the fuselage, the engine is about 4mm too low, so the spinner does not line up properly. If I tilt the cowl down, the alignment is better, but then the rear end of the cowl is 2 or 3 mm above the fus - spoiling the look. My dilemma is: do I accept that the cowl is not accurate, and bodge it as best I can - or do I raise the engine 4mm to line up with the "best position" cowl, and risk the thrust line being out? I've emailed Seagull and Perkins for advice and await their replies, but if anyone has any thoughts I'd be grateful to hear them. Cheers - Les Holloway Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 19, 2009 Author Share Posted October 19, 2009 Hi Stakerjack, The model come with one servo per airelon. This combined with high torque units coupled with thick adjustable metal rod should fix the issue. Thanks for the heads-up. Regards, Federico Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 19, 2009 Author Share Posted October 19, 2009 Hi Les, I'm glad you are working on the same project! Information sharing could potentially save us some hassle. For the engine installation I adopted the opposite solution going for the electrical option thrust line. The only reason was that this position was aligning perfectly with the cowl front hole. The other thing I considered was that not having to drill an other series of holes would have give me the option to find a better location after if things are not working ok. Can you tell me if you choose to beef up the fire wall in any way? Did you also used the supplied hinges or did you replaced them with different units? I could not get my hand on the Zap and triangular balsa stock a the week end so I have no building news to report. Regards, Federico Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 19, 2009 Author Share Posted October 19, 2009 I have a question about cowl vents and air intakes. As the real thing has a quite large air intake below the propeller I will replicate the same on the model without spoiling the look. From a vent point of view thing are a bit more complicate. My plan of action is to replicate the right side louver plate as per original. I've aluminium and a brass plates and I was planning to use some for this poupose. The brass is thinner but I guess the aluminium is easier to cut. I was thinking to use a large wood chisel to open up the louvers. Suggestions? I do not think that the louvers on the right side will be sufficient to expel all the air coming from the intake, for this reason I'll drill out the 6 exhaust holes on the bottom of the cowl too. Regards, Federico Quote Link to comment Share on other sites More sharing options...
Les Holloway Posted October 19, 2009 Share Posted October 19, 2009 Hi Federico - I didn't beef up the firewall, mainly because when I peered inside the fus there was a substantial glue fillet all around the firewall joint. I also used the supplied hinges as I have never had a problem with these 'fuzzy mylar' types, even unpinned. In this case, to be on the safe side, cocktail-stick pins will be inserted from the underside. Like you, I am planning to replicate the right side louvre in very thin aluminium, but not as a functional item. Haven't yet worked out how I am going to cut the louvres! As I need access to my Laser carb and plug from below, I need a fairly large vent in the bottom of the cowl. I shall try to make the front cut-out match the one on the full-size. I also intend to make internal baffles to direct incoming air over the cylinder head. Regarding my engine / cowl alignment problem, I have now had a reply from Perkins, who say their demo Mew Gull also needed the cowl tilted slightly down to line up with the spinner. However, they also say that moving the engine a few mm upwards should not affect the flying performance. Meanwhile Seagull in Vietnam have passed on my enquiry to someone who sounds American - may even be the designer... I await his comments with interest. Cheers - Les Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 20, 2009 Author Share Posted October 20, 2009 Hi Les, you are right about the glue around the firewall but in my one is just about visible. I'll add some extra epoxy and balsa fillets for good measue as I'm not familtiar with pertol engine vibration levels. I got some zap this morning so I'll try the mylar hinges tonight. I'm still short of few bits but as I'm drivig to Belfast at the week end I hope to find what I need there. I'm very courious to see the replay from seagull about the thrust line. I was looking at the instruction manual and the electric conversion firewall look different from the one in my kit. In the manual the firewall thrustline line-up with the one on the main firewall while in the kit does not. As per the Perkins guy I think that down and right thrust are more important than keeping the centre line of the engine on the plane datum line. Anyway I do not even know if the lower position achieve this objective. If you have any pictures of your plane please do post them in this thread. Regards, Federico Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 21, 2009 Author Share Posted October 21, 2009 Got the Zap! I've got all hinges sorted in wings and elevator halves as per instruction but I did not agreed with the fin/rudder hing installation before fitting the fion the fuse. I glued the fin assembly to the fuselage with 5 min epoxy after removing the cover film as per instructions. I also remove the film from the bottom tail cone gluing area. I try the tail wheel assembly and discover than the wheel rudder shaft did not sit parallel to the fin/rudder at all. This potentially will introduce strain on the hinges. I fix this adding two washer below the back screw on the tail assembly. By the way the instruction call for three screws to retain the wheel but only two holes are present. Despite the shaft now lineing up there still a bit of side movment on the wheel shaft when the rudder move. would have prefered a different system similar to the sparrowhawk to reduce the strain on the rudder hinges. Before getting at the tail I tryed to add epoxy and a couple of balsa filletts on the inside of the firewall. This prove to be a hell of a job as the acess to the area will be an issue for an Hobbit! I managed anyhow to get some of the planned work done. Water based dulux diamond coat wood varnish was used to fuel proof the fire wall and tank bay, again the last item was a nightmare to reach so do not know how well the job turned out. Overall I'm quite pleased the only snag is that after I got the rudder glued to the fin I noticed that the alignment of the two is not perfet as the rudder top is slightly out on the right side. As this is a minor issue it is probabilbetter to stick with it rather than tamper with the hinges increasing the risk of less than secure bonding. That's all folks!! Regards, Federico Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 23, 2009 Author Share Posted October 23, 2009 Hi, I've started looking in the tail plane halves set up. The instruction are calling for two 7cm long 3mm OD steel rods. This two items as the main aluminium brace tube, shall be fed through the pre drilled holes below the fin assembly. The main brace tube is a perfect fit and match both fin and tail plane halves just righ. Not the same can be said for the two steel rods, these item are not 3mm but 2.5ish. Once you slide them in the receptacle holes they are completely loose. I decided to ditch the two and replace them with 3mm brass rods cutted from a welding rod. The fit is now perfect and I'll soon epoxy them in place before I do the same with the elevators halves. The more I look into the wing/tail design the more I'm convinced that Segull with very little extra efford coul have provide the existing set-up with grub srew retainers allowing the dimantle of both main wing and tailplane for easier transportation. Regards, Federico Quote Link to comment Share on other sites More sharing options...
Peter 'Ivanna Crashalot' Savage Posted October 24, 2009 Share Posted October 24, 2009 It is a very nice aircraft! Dad's got a seagull EP Decathlon, it was quite well constructed. Offtopic: My grandad worked at percivals after the war, think the mew gull was before the war and the original G-AEXF is at RAF hendon in london Edit: it is a replica at hendon, the real one is in yorkshireEdited By Peter Savage on 24/10/2009 21:13:38 Quote Link to comment Share on other sites More sharing options...
Les Holloway Posted October 27, 2009 Share Posted October 27, 2009 Hi Federico - You're right about the transportation issues. I keep looking at that six-foot wing, complete with undercarriage, hanging in the rafters of my workshop, and wondering how I am going to fit it into my modest hatchback! I also share your thoughts on the tailplane fixing, although I've done mine mainly by the book' and it all went together very nicely. I had my doubts about the whole of the tail feather assembly being held in place by a relatively narrow glue bond, so I increased the surface area by building up with thin ply in strategic places, and used 30-min epoxy. As far as the two locating wires for the tail plane halves are concerned, mine are also short, but as they are only going into a single rib I don't think that matters, I cyanoed them in place in the fin base before sliding on the tailplane halves on the main brace tube, using 30-min epoxy again. Still haven't heard from the Seagull guy about my engine alignment issue... Hi Peter -You've presumably found the RAF Museum website which gives you a 3D view of both the replica Mew Gull at Hendon and an internal full panorama of the cockpit, and also the stuff at the Real Aeroplane Company at Breighton Aerodrome, where the real one is based. There are quite a lot of nice pix of G-AEXF on the JetPhotos.Net website. Cheers - Les Quote Link to comment Share on other sites More sharing options...
Graham Ashby (Editor) Posted October 28, 2009 Share Posted October 28, 2009 Interesting to read your comments guys. Short of adding the stickers my Mew Gull is practically ready to fly. I too had the same issue with the cowl, engine thrust line and spinner / nose ring relationship but opted to leave the set-up alone as I'm duty bound to put the model together 'as is', it being a review an' all. Mind you, I'm not too distressed about the appearance of the cowl. It'll be interesting to see if anyone at the club notices. Agree that the cockpit is bland, though I plan to remove the canopy very shortly after the review's put to bed and do something with it, i.e. extend the dash further into the cockpit as a continuation of the forward fuselage decking, add a better instrument panel, and fit a 1/4 scale latex pilot. I'm tempted to add a pitot tube and a few panel lines, too. Engine: Saito 150 installed as per kit with the exhaust exiting on the underside. Had I been building it entirely for myself I'd have fitted it inverted and fully cowled. Has anyone heard any comments about how the model flies? I'm getting close enough to the test flight to be very interested. Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 30, 2009 Author Share Posted October 30, 2009 Les, Graham, would you be so kind to tell me your servo choice for the Mew Gull? Regards, Federico Quote Link to comment Share on other sites More sharing options...
Graham Ashby (Editor) Posted October 30, 2009 Share Posted October 30, 2009 Yes, I'm using six SuperTec S03T / 2BB servos - 5.8kg-cm torque but noticeably slow, not that speed is much of an issue in this instance! Quote Link to comment Share on other sites More sharing options...
FEDERICO GILLI Posted October 30, 2009 Author Share Posted October 30, 2009 Thanks Graham, I got my box of outstanding bits last night. The hawk wooden prop 18x10 look impressive and it is probabily the closest thing to scale I can fit in an I/C non geared set up! The prop appear to have enough meath around the shaft to allow for the multi bolt roto prop hub. So I need to drill the prop next. On this I've planned to use only 2 of the 4 bolts supplied I hope this will be sufficent. Shall I drill the prop perpendicular to the blades or in line with them? The alluminium spinner I ordered look nice too but I'll tell you more after I balace it. I also got an heavy duty CRRC power switch complete with led and charge socket to be used as supply / kill switch to the injection system. I'll use a standatd switch for rx and servos. Speaking of servos I got my 9kg MG Spring-rc servos. They looks good and have been supply with a substantial array of arms. I need to set them up into my new yamamoto to check them in the air. As the loads in the Mew Gull are not goint to be huge I hope they will work fine. Some 6x3mm pertol fuel tube was part of the order so I can now fit the tank. As I have a number of different commecial glow inline filters I was wandering if I can use any of them with petrol. Any suggestion on this? Thanks a million. Regards, Federico Quote Link to comment Share on other sites More sharing options...
Les Holloway Posted October 30, 2009 Share Posted October 30, 2009 Hi everyone – Re servos – I’m using Hitec HS-5625MG digitals – 9.45 Kg.cm torque on the 6v battery I’ve installed. That’s probably overkill for this model, but I was thinking ahead to a large aerobatic machine… Here are some pix of my cowl problem – sorry about the crap photography – cramped workshop and I’m still experimenting with a new camera. 1 The Laser 150 installed on what I reckon is the right thrustline: 2 The best cowl fit I can get with the engine in that position: 3 Not too bad, you might think – but this is what the back end of the cowl looks like: 4 And if I get the cowl to sit properly on the fus, this is what happens at the front end: That’s really not acceptable, so I reckon I am going to shift the engine 3mm or so higher and hope that the altered thrust line is not going to affect the flight performance too much… Graham – I’m really looking forward to your review! Cheers - LesEdited By Les Holloway on 30/10/2009 13:44:24 Quote Link to comment Share on other sites More sharing options...
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