Danny Fenton Posted September 26, 2020 Author Share Posted September 26, 2020 I am drawing the plans for a 1/4 scale Chippy, but don't tell anybody I have done all 5 views, have to revisit the full size to check some dimensions. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted September 26, 2020 Share Posted September 26, 2020 Drifting off subject again Mr. Fenton lovely aeroplane the Chippy but so is the Apache, the Nimrod/Fury and the P 51. Must admit I used to do that now I concentrate on one at a time as I would hate to leave my family a heap of unfinished projects to sort out, not that I am planning on going anywhere for a long time . Cheers Eric. Quote Link to comment Share on other sites More sharing options...
Gary Clark 1 Posted September 26, 2020 Share Posted September 26, 2020 Excellent Danny. I have the plan for the Jerry Bates 1/4 Chippie but never got around to it so could Build a Danny Fenton one instead in the future! I also struggle with finishing projects Eric but haven't developed the discipline of staying on one subject at a time. Maybe I'll teach myself that in the future! Gary Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted September 26, 2020 Author Share Posted September 26, 2020 I thought I was doing very well The Apache is waiting flight tests, as is the Fury, and a Hurricane, not to mention a Grumman Trainer. I don't have access to a decent flying site at the moment, so I am supposed to be alternating between a day on the Mustang and a day on the Chippy, alas that plan seems to have gone a tinsy bit awry Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted September 26, 2020 Author Share Posted September 26, 2020 Hi Gary, I have the Jerry Bates too, and the Dave Womersley, neither are quite right. Though Dave's is closest. I took part in my first R/C BMFA scale comp at Blackpool on Sunday and it has fired me up to get a decent model built, I have been talking about it long enough I didn't do that well on Sunday, but I didn't come last either. A Fenton Chippy, now I like the sound of that Cheers Danny Edited By Danny Fenton on 26/09/2020 22:22:49 Quote Link to comment Share on other sites More sharing options...
Gary Clark 1 Posted September 26, 2020 Share Posted September 26, 2020 Well I'd be a willing customer Danny and I'm sure plenty of people on here would too. I'm still patiently waiting for you to publish a plan for the Apache also! Gary Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 5, 2020 Author Share Posted October 5, 2020 Hi Gary, patience my friend Well I am stuck and cannot do any more on my Chipmunk project until I get to the 1:1 and take some measurements. So I thought I better get back onto the Mustang. Final aileron fitted need to sort some servo trays and set up the RDS. It may mot be much progress but it is progress none-the-less Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 6, 2020 Share Posted October 6, 2020 Just found this Danny, now following along... Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 6, 2020 Author Share Posted October 6, 2020 Great to have you aboard Martyn Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 7, 2020 Author Share Posted October 7, 2020 A quick test of the RDS for the flaps, still need a bearing block near the rear spar to stop the piano wire "wandering" but seems to work okay. The RDS adaptors are not gripping the piano wire as well as alloy ones would, might have to file a flat in the wire to assist. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 7, 2020 Author Share Posted October 7, 2020 Filed flats in the piano wire and added a simple balsa guide between the rear spars, (I will face this with some 1/16 ply as a bearing surface). All seems to be set up okay, will have to check with the TX as i never trust these servo testers to get the extent of travel right. Lovely thing about RDS is you can slide the surface back off, no linkages to mess with. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 7, 2020 Share Posted October 7, 2020 That looks great Danny. Where did the 'top hats' come from? Martyn Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 7, 2020 Author Share Posted October 7, 2020 Hi Martyn, Eric Strefford printed them for me. They seem robust enough, the one area we are worried about is the grub-screws are in threaded plastic. I have used two 3mm grub-screws, and filed flats on the torque rod. The wooden block has made things much more solid, I faced the block with a small square of 1/16 ply to beef up the bearing surface. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 8, 2020 Share Posted October 8, 2020 I was going to 3D print some as well but insert a brass collet into the centre and use long grub screws that would engage with the plastic outer. That would also give me a big enough access hole to get at the servo arm screw as well. They do look great. I will be using RDS on my next scale model Martyn Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 8, 2020 Author Share Posted October 8, 2020 For these wing servos the size is just about optimum. The hole down the centre is always at least 2mm which allows a jewellers driver to do up the servo screw. I cant see how you would lock the collet to the printed top hat. I think the answer is maybe a harder plastic than PLA?? Though saying that these have worked. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 8, 2020 Share Posted October 8, 2020 I think the answer would be an alloy collar around the printed part so that the retention grub screw is threaded in that. I’ve done that with other 3D printed parts where I needed a ‘stronger’ thread that that provided by the plastic. Alternatively just machine an alloy top hat (I believe they are commercially available). Have you thought about an IDS system at all Danny? Used a lot in gliders IDS Edited By Ron Gray on 08/10/2020 13:32:53 Edited By Ron Gray on 08/10/2020 13:41:10 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 8, 2020 Author Share Posted October 8, 2020 Hi Ron, yes there is a commercially available RDS adaptor, they are very expensive for what they are. They are not of this design. These are unique. I have, and do make them from alloy normally, see below, but that takes time, and the 3D printed items are very quick to produce. We will see if the printed ones perform over time. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 8, 2020 Share Posted October 8, 2020 What about the IDS ones Danny, they are 'cheap' but do the job on gliders of all shapes and sizes! The other ones I've seen are the MKS ones, which aren't that expensive MKS Edited By Ron Gray on 08/10/2020 16:28:47 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 8, 2020 Author Share Posted October 8, 2020 The problem with the aftermarket units is that you have to get the exact size to fit your servos, spline count and diameter. For example the IDS one you show is for the MKS servos, £70 a pop, way outside my market. IDS is a new one on me so thanks for pointing it out. I thought it was similar to what I called moving fulcrum which will only give a low angle of surface deflection. But actually it isn't. Looking at the moment arms I cannot see how its going to provide a solid surface at neutral. The airflow on the glider wings is probably lighter so wont matter as much. I believe the DS guys mainly use RDS. The ones I make will fit any servo and only require an alloy (or printed) "top hat" and 2mm piano wire. Its far simpler. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 8, 2020 Author Share Posted October 8, 2020 The problem with a wing that has no fixed trailing edge is alignment of the flap and aileron. I made a jig to get the flap angle correct. Aligned the aileron to the flap and then made a false wing tip from some scrap balsa. This allows me to align the aileron to the tip, and the flap to the aileron. One I am happy I can remove the false tip and carve a real one. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 8, 2020 Share Posted October 8, 2020 IDS also for Bluebird and Futaba servos from Hyperflight, but agree that the piano wire RDS is possibly simpler. Diagram for fitting of IDS ‘horn’ IDS fitting Edited By Ron Gray on 08/10/2020 18:16:49 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 9, 2020 Author Share Posted October 9, 2020 Second flap sorted. I had to go back to the first flap and tweak the position of the torque rod, just to ensure I had enough travel to cover flap fully up and down plus a little for adjustment on the Tx. Ailerons next, they should be much easier. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 1, 2020 Author Share Posted November 1, 2020 Been concentrating on my two Chipmunks getting them sorted, all good to go now, so back on the Mustang. Had a lot of trouble with the ailerons, the RDS would not work properly, with the hinges pushing out at the extremities. The problem is the hinge lines and pockets cannot be in perfect alignment. I have tweaked things as best I can and is much better. But of all the RDS set ups I have done this is the first to cause me grief. Mustn't get complacent and be more careful with alignment in future. Anyway while messing around I managed to strip Eric's 3D printed RDS adaptors, my own fault, you should use the grub screws to cut the threads, I didn't I used a tap. Unfortunately although it was an M3 it was .6 (fine) not .5 which would match the grub-screws. Rather than wait for Eric to print some more I ran a couple up on the lathe in T6 alloy Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 28, 2020 Author Share Posted November 28, 2020 I have been really nervous about the wing skins. The wings have to be absolutely perfect and no undulations or these 1/16th skins will highlight every error. Hence my fear. The trailing edges also have to meet the ailerons and flaps, which is another worry. I thought long and hard about how to do the skins, and in the end opted for joining two lengths of 1/16th and do the skin in one piece. I glued all around the perimeter and gently attached the skins, they are only pinned at the edges, but there is no play when you gently press the skin. the idea is the natural curve of the wood will mean no ripples. I made a duplicate of the starboard skin as it fitted the port side perfectly. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 2, 2020 Author Share Posted December 2, 2020 Managed to finally drum up some enthusiasm to add the second section of upper wing sheeting to my P-51. Will try and get the underside done tomorrow. Wing is still nice and straight thankfully, the lower sheeting behind the spars should lock the wings hopefully, then it's the dreaded retracts..... Quote Link to comment Share on other sites More sharing options...
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