Tim Kearsley Posted September 12, 2021 Share Posted September 12, 2021 I guess that's what keeps us interested Andy. When you're new to the game though there's so much you don't know and I suspect you don't know what you don't know sometimes - if you see what I mean! Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted September 12, 2021 Share Posted September 12, 2021 I got you Tim. That is why, like many others here, we enjoy passing on our experiences to others for them to learn from Quote Link to comment Share on other sites More sharing options...
Paul Johnson 4 Posted September 12, 2021 Share Posted September 12, 2021 I could write pages of good advice on how to cock it up!!! 1 Quote Link to comment Share on other sites More sharing options...
Tim Kearsley Posted September 12, 2021 Share Posted September 12, 2021 Well when I first got into this hobby, back in about 2006, I assembled my first ever ARTF. I knew nothing about glues and their characteristics. I came to needing to slot the fin into the fuselage (I think it was an Extra or Edge, from memory). I coated the tongue of balsa that slotted into the fuselage with medium cyano. It was quite a tight fit and as I slotted it in the cyano went off - with the fin about half in!! It was locked solid of course and had to be cut out. You do learn by your mistakes! Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted September 12, 2021 Share Posted September 12, 2021 Sadly we keep making them too, but they vary all the time. My last error was with the Spitfire from Richard. My motor ESC was getting a touch too warm so I flew it without the spinner to help get more cooling air in. Worked great to about 50 feet up where the plane started getting in its stride. This extra air popped my battery hatch in front of the cockpit off, the turbulence created from the void / formers was sufficient to blanket the tail feathers so no vertical control and into the ground she went at around 50mph. The tail now resides over the door to my aircraft building shed. Quote Link to comment Share on other sites More sharing options...
Graham R Posted September 12, 2021 Share Posted September 12, 2021 7 hours ago, Paul Johnson 4 said: You don't have to take it too far just enough to clear the nuts. Posh looking model stand Paul. Quote Link to comment Share on other sites More sharing options...
Paul Johnson 4 Posted September 12, 2021 Share Posted September 12, 2021 Not that posh...HK Have had the ply laminate separating in a few places. But it is useful. Quote Link to comment Share on other sites More sharing options...
Paul Johnson 4 Posted September 12, 2021 Share Posted September 12, 2021 Forgot to mention about the clearance, careful with your nuts... don't get them near the propeller..... Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted September 13, 2021 Share Posted September 13, 2021 15 hours ago, Paul Johnson 4 said: I could write pages of good advice on how to cock it up!!! As I have said many times, I have learned much from making mistakes that I keep making them so I san learn more. 1 Quote Link to comment Share on other sites More sharing options...
Tim Kearsley Posted September 13, 2021 Share Posted September 13, 2021 18 hours ago, Paul Johnson 4 said: Forgot to mention about the clearance, careful with your nuts... don't get them near the propeller..... I'm always most careful with my nuts, especially around propellers. 1 Quote Link to comment Share on other sites More sharing options...
Jonathan S Posted September 17, 2021 Share Posted September 17, 2021 All, I am going to do a bit of covering with brown paper tonight for the first time. I have Richards instructions ?. But does any body have any hints and tips. I am planning on using Gorilla wood glue. The next big job will be wing attachment and Wing Fairings, everybody seems to have skipped over how this goes together in their blogs or done it slightly differently so any hints and tips would be welcome. thanks Jon Quote Link to comment Share on other sites More sharing options...
gillyg1 Posted September 17, 2021 Share Posted September 17, 2021 Jonathan. Use the cheapist pva you can find .. Gorilla is expensive. Dilute around 10% Apply too dull side of brown paper with a soft brush, like wall papering. Allow to "grow" for 30 seconds ish. Apply to surface, smooth out from the middle useing a soft cloth. When wrinkle free, iron on. I use a travel iron, temprature set to number 1. PVA reacts too heat. Its a "doodle" Graham, cornwall Quote Link to comment Share on other sites More sharing options...
Gordon McConnell Posted September 17, 2021 Share Posted September 17, 2021 Hi folks, Back to working on the P-51 after a delay due to all sorts of things. The wing and fuselage are covered now in Solartex and painted. Not the lightest or cheapest solution but will be strong! I have fitted the flaps and been installing the servos and the linkage. I chose to use two servos as Paul has done and run into a problem. I can get the servos to run the flaps from stowed to deployed position but the servos are jittering and humming at the extremes of travel. When the flaps are retracted, the servo is still actively trying to retract them further don't think they would last long doing that so I have been adjusting the centring and throws of the servos in an attempt to quieten them down. Part of the problem is that when the flaps are fully retracted, the linkage is over top dead centre so to speak and is not in a straight line causing a higher load on the servo. I am wondering if Paul or anyone else has run into this problem and found a solution? I am concerned that if one servo fails the flaps may be asymmetrically deployed with unspeakable consequences! Thanks. Gordon Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted September 17, 2021 Share Posted September 17, 2021 Would ball joint linkages help ? bit more tolerant to slightly off line. 1 Quote Link to comment Share on other sites More sharing options...
Trevor Posted September 18, 2021 Share Posted September 18, 2021 Lengthen the flap horns as far as you can. You may then be able to use more travel on the servo which will reduce the load. Also the further forward the servo arm goes to retract the flap, the less the load on the servo in the retracted position. Quote Link to comment Share on other sites More sharing options...
RICHARD WILLS Posted September 18, 2021 Author Share Posted September 18, 2021 10 hours ago, Gordon McConnell said: Hi folks, Back to working on the P-51 after a delay due to all sorts of things. The wing and fuselage are covered now in Solartex and painted. Not the lightest or cheapest solution but will be strong! I have fitted the flaps and been installing the servos and the linkage. I chose to use two servos as Paul has done and run into a problem. I can get the servos to run the flaps from stowed to deployed position but the servos are jittering and humming at the extremes of travel. When the flaps are retracted, the servo is still actively trying to retract them further don't think they would last long doing that so I have been adjusting the centring and throws of the servos in an attempt to quieten them down. Part of the problem is that when the flaps are fully retracted, the linkage is over top dead centre so to speak and is not in a straight line causing a higher load on the servo. I am wondering if Paul or anyone else has run into this problem and found a solution? I am concerned that if one servo fails the flaps may be asymmetrically deployed with unspeakable consequences! Thanks. Gordon Gordon , As the servos go over centre and try to pull the rods up against the central hub of the servo , why not just make the rods arch over the hub ? They will still push the flaps down , Also, since the ARTF brainwashing has made everyone think that we should have a separate servo on every vital control surface , then why do we not drive each elevator individually ? All through the 70s and 80s we saw models with only one Futaba 148 aileron servo . I personally have never seen one fail . I cant say that about the selection of mini servos I have in my fleet. 1 Quote Link to comment Share on other sites More sharing options...
Paul Johnson 4 Posted September 18, 2021 Share Posted September 18, 2021 Gordon also check that the retracted position has no resistance when fully up, things like covering binding against the top wing skin or not letting the flaps fully close. Ideally without the servos attached the flaps should rest totally closed when you invert the wing. If not then this also could be a cause of the servos humming. Quote Link to comment Share on other sites More sharing options...
RICHARD WILLS Posted September 18, 2021 Author Share Posted September 18, 2021 I hum a bit ...... Quote Link to comment Share on other sites More sharing options...
Paul Johnson 4 Posted September 18, 2021 Share Posted September 18, 2021 Maybe so but I've heard your singing so stick with the humming.... Quote Link to comment Share on other sites More sharing options...
Gordon McConnell Posted September 18, 2021 Share Posted September 18, 2021 Thanks Richard. I will check it out and do a little humming myself.? Quote Link to comment Share on other sites More sharing options...
Gordon McConnell Posted September 18, 2021 Share Posted September 18, 2021 All good advice guys. Thanks. Ball joints on the flap lever and lengthening the flap lever would be ideal. I will have a think about how to arrange it. I agree with you Richard on the single servo option. I used two servos as I thought that it would be easy to adjust the servo travel to have the exactly same flap angle each side. Probably adding too much complexity just to avoid making up a Y linkage and adjusting it to suit. Thanks again everyone. Quote Link to comment Share on other sites More sharing options...
Tim Kearsley Posted September 18, 2021 Share Posted September 18, 2021 Gordon, I had very much the same problem. I increased the horn length as much as I could to maximise the torque from the servos. Also, I use FrSky kit and the way I set up flaps is to use a three-point curve so that the two end-points and the centre can be set up precisely to avoid binding at the extremes of travel. Quote Link to comment Share on other sites More sharing options...
Jonathan S Posted September 18, 2021 Share Posted September 18, 2021 I have just covered the flaps and they are sticking a bit so more sandpapering as they are sticking. I am wondering if to go for 2 or 1 flap servos. Any advise, what's the pros and cons? Thx Jon Quote Link to comment Share on other sites More sharing options...
Tim Kearsley Posted September 18, 2021 Share Posted September 18, 2021 It's down to personal choice Jonathan. I always go for two servos as I think it makes getting the flaps adjusted for equal travel and end points easier but others will disagree I'm sure! As I replied to Gordon in an earlier post I use a curve on each servo channel to ease the end point setting. Quote Link to comment Share on other sites More sharing options...
Paul Johnson 4 Posted September 18, 2021 Share Posted September 18, 2021 Jonathan There are pros and cons for both as you would have seen here. A single servo failure isn't a drastic as one flap failing (I as yet after 5 yrs haven'thad one fail). 2 smaller servos are lighter than one larger one. The decision is yours. Quote Link to comment Share on other sites More sharing options...
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