GrumpyGnome Posted February 13, 2021 Share Posted February 13, 2021 Morning all As you may have seen from some other posts, I am currently building a P-47 from the Seagull kit. The kit comes with a set of mechanical retracts.... these feel solid enough but general opinion seems to be that they be replaced with electric units. I can't find many 85 degree units at a reasonable price, but can find 90 degree units. As they retract inwards, they would be splayed outwards when extended. If any units I buy can't be adjusted (I have some Hobbyking ones that can be adjusted), I think I have a few options: 1. Live with splayed wheels when deployed 2. Cant the bases by 5 degrees so vertical when deployed with the wheel being lower in the well when retractd 3. Cant the base, and adjust the covers so they are flat with the wing when retracted and have a slight gap between cover and leg. Thoughts ? I have to admit that my current thoughts are to either try the mechanical units, or take option 3. above . GG Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 13, 2021 Share Posted February 13, 2021 (edited) If the retracts that came with it feel solid just use them. Why waste money? Most problems with mechanical retracts came from poor setup, sloppy links and that sort of thing. Installed correctly mechanical retracts are no bother. equally, cheap electric retracts can be very unreliable and very fragile so i would probably fit the ones it came with, or at least mock them up and test them to see how they work. just make sure you get the travel right on your servo output arm (you may need to drill holes and make a custom arm) and it will be fine. Edited February 13, 2021 by Jon - Laser Engines Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted February 13, 2021 Share Posted February 13, 2021 (edited) My gripe with many ARTF's with plug in wing halves and supplied mechanical retracts is that you have to connect and disconnect the servo end plus when transporting and storing you have the exposed pushrod ends just begging to catch on something and bend. You can embed a servo in each wing panel but if you are buying two retract servos you may as well just buy a set of electric retracts. The metal trunnion ones from HK and the like are ok but if you don't mind spending a little more I've found JP units quite good. As for the original question - if I couldn't find 85 degree units at a price I like I'd live with the slight bandy legged look. Edited February 13, 2021 by Bob Cotsford Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 13, 2021 Share Posted February 13, 2021 I had forgotten about the plug in wings. Its another reason i hate them! With the power of modern mini servos its unlikely a dedicated retract servo will be needed. The futaba jobs were only about 5kg if i recall and that is not a great deal of power. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted February 13, 2021 Share Posted February 13, 2021 Ah, but they had a 180 degree rotation giving more effective power at the end of the travel for a positive lock owing to the mechanical advantage at low offsets from the servo output axis. Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 13, 2021 Share Posted February 13, 2021 i always used a geometric lock for gear down and then the up position was left to its own devices. In any case, a pair of retract servos (if required) would still be cheaper than a set of half decent electric retracts. Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted February 14, 2021 Author Share Posted February 14, 2021 The kit has a servo in each wing for the retract so no effort at the field. I'll give the supplied units a go........ Yeah, I had planned on mocking it up as access, once assembled, is pretty tight! Added benefit is that I can make them open and close nice and slowly ? Cheers gents, GG Quote Link to comment Share on other sites More sharing options...
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