Martin McIntosh Posted November 6, 2013 Author Share Posted November 6, 2013 Again a lot of work done but not much to show for it. On testing the legs it was found that the mounting bearers need to be angled backwards quite a lot (the opposite to a Spit for example).This entailed a fair bit of Dremel work and packing in order to get them to sit level in the wells whilst maintaining a straight track. You would be well advised to take a close look at the angles of these before cutting the slots in the ribs. Decided to change the door servos to Vigor MG. Luckily it was possible to reverse one of these without reverting to more electronics. A single `Landtastic` home made servo slow makes the sequence look realistic although I have yet to fit the linkages. The actual doors, made from alloy, are next but it puzzles me as to why they do not cover the complete wheel wells. Difficult to find a pic of the underside of a full size with the doors closed. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 6, 2013 Share Posted November 6, 2013 Hi Martin, I have a rather extensive library on the Mustang, this is a shot from the Hendon Museum Does it help? I threw in the second shot as its for an area I had to work hard to get details of. Its the Oil radiator flap. The larger more common water radiator flap is further rearward Cheer Danny Edited By Danny Fenton on 06/11/2013 23:48:15 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted November 6, 2013 Share Posted November 6, 2013 Tricky business retract U/C's. Looks like we've been spending tonight doing similar things Martin - you fettling the angles and me sorting cutouts! Its worth it in the end though - I mean you really can't have a P51, or any WWII standard fighter with the wheels dangling down! This any use to you? BEB Quote Link to comment Share on other sites More sharing options...
TinPot Pilot Posted November 6, 2013 Share Posted November 6, 2013 Martin, does this help? Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 7, 2013 Author Share Posted November 7, 2013 Thanks for the pics, they show them as I would have thought they should be. All the ones I have looked at are of small doors which the plan seems to mimic. Glad that I did not cut them out last night. Thinking about the angle of the bearers towards the upper surface, this was possibly done to give a retraction angle nearer to 85deg. but was not possible with the larger units I have chosen although there would be little difference at the end of the day. I am happy with the way that they have turned out so far. BEB - has anyone had chance to look at the `posting text after a pic` problem yet? Martin Mc. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 7, 2013 Author Share Posted November 7, 2013 A pic of a full size and one of the plan to show what I mean. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 7, 2013 Author Share Posted November 7, 2013 Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 7, 2013 Author Share Posted November 7, 2013 The site has gone really silly now and will only allow one pic at a time. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 7, 2013 Author Share Posted November 7, 2013 Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 7, 2013 Author Share Posted November 7, 2013 Really confused now. In the above pic the red lines I have drawn would seem to be correct but the pic of the underside would suggest that the dotted line is the join of the main and inner door. Either way these do not agree with the other pic of the main door with the legs extended. Any ideas? Maybe these are different Mks of the aeroplane. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 7, 2013 Share Posted November 7, 2013 Hi Martin, is it possible you are not taking into account that the doors shorten considerably when retracted due to the way the doors are attached to the oleos? Cheers Danny Edited By Danny Fenton on 07/11/2013 23:23:40 Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 8, 2013 Author Share Posted November 8, 2013 Ah, all is clear now. A bit beyond my building skills to do that. My models are `stand as far away as you can get` so I shall have to compromise to make it look right on the ground at least. Thanks again Danny. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 8, 2013 Share Posted November 8, 2013 Nonsense Martin you are more than capable, mind you I admire you for being able to step away from that level of detail wish I could sometimes. I have those very doors to do on my Mustang when I get back to it........ That website by the way MustangsMustangs is an awesome reference site Cheers Danny Quote Link to comment Share on other sites More sharing options...
Codename-John Posted November 8, 2013 Share Posted November 8, 2013 This site is also excellent for 3 view drawings etc, and his model is equisite Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 8, 2013 Share Posted November 8, 2013 When I looked at the Spiteful/ Seafang I found the same thing. The door isn't attached rigidly to the leg, it's hinged to the wing with an articulated connection to the leg. Because the leg and the door rotate on different centres, in the closed position the door is effectively shortened by the distance between the pintle/hinge positions. I think I exchanged with Danny on the idea of attaching the door to the wing instead of the leg on a potential larger model and he advised against it from experience (it was you Danny)? Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 8, 2013 Share Posted November 8, 2013 Hi Colin, yes it was me I think. What we discussed was hinging the undercarriage door along the length of the oleo leg not against the wing. hinged on the wing skin should work if rigid enough I have a YT Hurricane, and there has been no thought given to the pintle angle when this was designed. This really presses my OCD button and I tried lots of ways to make the door pivot about the leg axis. This was in an attempt to get the door to lie flush when retracted and parallel to the wheel when lowered. I made all sorts of prototypes, most resulted in massive flutter during flight and came off! Anyway the bottom line was (for me), build the correct pintle angle in the first place...... Cheers Danny Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 8, 2013 Share Posted November 8, 2013 Hi Danny. If that was how you interpreted what I asked, I clearly did a lousy job of trying to explain what I meant. (Nothing new there then)! My interest was in the practicality of hinging the door cover to the wing skin and attaching it by some flexible means to the oleo leg. It was the only way I could see of replicating the u/c on the Spiteful and it looks the same on the Mustang. I suppose on a smaller scale model it's not worth the hassle, but perhaps on a 1/7 or 1/6 plus model, it could be worth having a bash. It would mean that when landings are a bit ropey (mine) and the oleo gets bent back, there would need to be some give in the attachment to the oleo to avoid breaking the hinge, in addition to the articulation needed to deal with the shortening issue caused by the dissimilar centres of rotation we referred to before. It looks as if Martin is going to compromise on this one, can't blame him and I doubt if anybody will comment because it's generally what we do anyway. Still got me thinking though. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 8, 2013 Share Posted November 8, 2013 Hi Colin, I wouldn't be too hard on yourself it is just as likely to be me not reading the question properly, I am often doing that I think hinging on the wing skin, or a rib perhaps should be fine. I have seen a pair of ball joins used, one either side of the oleo. This video shows how it should be done Cheers Danny Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 8, 2013 Share Posted November 8, 2013 Thanks Danny. I like the look of that and clearly it's close to scale anyway, so even better. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 8, 2013 Author Share Posted November 8, 2013 You have me thinking about this now, and I thought that it would be just the inner doors and sequencer which would give problems! The ones in the video are awesome. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 8, 2013 Author Share Posted November 8, 2013 Just playing with an idea here but it will stop if I decide that it would be unreliable since I want this to be a practical model. Doing a mock up of what they may be like. Quote Link to comment Share on other sites More sharing options...
Tim A Posted November 8, 2013 Share Posted November 8, 2013 Hi Martin, been following your build with interest, have the P51-B on my todo list and have received the full kit from Tony having found a cheap way to courier it here to NZ. Not starting from scratch on this one, got a similar project on the go at the mo. Actually has saved myself a bundle, Tony's frieght cost would have been over approx 250 pounds, got it here for approx 70 pounds. Even the wood pack saved was well under 1/2 what I would have had to pay if brought locally! Thanks to local boat building industry. Anyway been thinking of a simpler way to work the inner gear doors than using servos/sequencer, what are you thoughts on a simple spring to hold the door open and using the wheel to retract. Not exactly scale operation but possibly easier to manufacture? Kiwikanfli. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 8, 2013 Author Share Posted November 8, 2013 Hi Kiwi, I seem to have lost the post I just sent to you but the gist is that I only intend to use elastic thread on the tail wheel and that a sequencer seems to be the way to do the mains, Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted November 8, 2013 Share Posted November 8, 2013 The ones in the video are scary! I'm at about this stage with the Tiffie and I have to said a bit devoid of good ideas at the moment for a solution that is simple to implement but which will close the doors without a big (bigger?!) gap at the top. BEB PS Martin we've looked at the text following picture problem - and I'm sorry to say it but it seems to be at your end. As you can see your Danny's thread above and my Tiffie thread others or not having a problem. Send me a PM to decribe the problem - exactly what you are doing - rather than us clutter your build blog discussing this as we try to sort it. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 9, 2013 Author Share Posted November 9, 2013 BEB, you are probably right here since I noticed that most are not having the problem. Kiwi, sorry, I got cut short there. I have used elastic thread successfully on a Lanc. but the difference is that it had 6" wheels going up vertically which gave a lot of movement in the elastic. Also the horn arrangement allowed the same piece of thread to close the doors so it was not working against a spring. I took a retract unit apart and there is just enough meat on it to screw on a hinge plate which would be better than trying to fix to the wing skin. The doors will have to be from a thin material, maybe GRP, since they will need to sit over the skin, not inset. Back to the shed, and more head scratching. Quote Link to comment Share on other sites More sharing options...
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