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JayW

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JayW last won the day on February 12

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About JayW

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  • Birthday 06/05/1951

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  1. Peter - Now THAT is what I'm talking about! Looks about right. Consider me satisfied. You say you shortened the gear? Good. And the link orientation looks good too! As far as rake angle is concerned, if you can wring a degree or so out of it, I think it will be fine. The other thing to be careful of is the other aspects of hanging the door. The front link is straight as you know, and the rear one has a big kink in it, but I believe the links are the same length. Even so it isn't obvious how the door hangs, either inbd/outbd, or fore/aft, or at what angle (toe in or toe out). You may have noticed the door kinematics is not parallel with the gear itself so the attach lugs are at an angle to the other features on the gear strut. That just complicates things further. Do not use fairing drawing 73-33302 to orient the door to the strut - although it shows the oleo centerline in the field of the drawing, the door is defined in the retracted position, looking down on the wing reference plane (not normal to the outside surface of the door, which BTW is far from flat as you know). So the as shown door is actually foreshortened a bit. Far better is to take the various views on the LG installation drawing 102-33001 and just measure the dimensions after determining the approximate scale of your drawing print. And then much study of various pictures helps of course. The P-51 aficionado will spot it right away if the door is hung wrong! So happy hunting. Let me see if I can find something on that antenna. Later.
  2. Upon my word! (how's my British?) Your latest details are just stunning shrink ray stuff. "I have 1 & 1/16 inch from skin to lug and the door seems to sit right - at least it does on dry runs, I will have to fettle it when I put it all together..." Let me get this straight - 1.06 inch from lower skin to the door lugs? Or the torque link lugs? And, to the lug holes? If the 1.06 dimension is to the door lug holes, then your upper strut is too long. By a good bit (about .13 inch). And I am sounding the alarm. Per the above sketch, of which I am certain of its accuracy, the measurement from wing lower skin to door lug should be 1.08 - .146 = .934 inch. +/_ .02 inch would be fine. Please check my numbers if you feel unsure. Did I misunderstand? If by "lug" you mean the torque link lugs, then that will probably be OK but still a tad long. Can the upper end of the struts be cut back if necessary? It appears to me they can without much if any impact. Another way to check is to approximate the orientation of the door links (dry fit the gear and door and inspect the link attach points). The link should be very nearly level (horizontal). Actually, the door side attachment of the link should be a smidge LOWER than the gear side attachment, giving a slightly downhill orientation (down outboard, up inboard). Check pics of Mustangs and this will be very evident. I suspect if you do this, you will get the opposite - the links will tilt up outboard. And that will be noticeably incorrect. Another good check is to look at the gear and door from the side. The lower edge of the door should be just barely above the axle cap of the wheel, hiding nearly half the wheel spokes. I recognize that this relationship depends on how much gear oleo extension you have, but we have already gone over that and yours is within a realistic range for an aircraft resting on the ground. I suspect you will find your door edge is well above the axle cap, and exposes much more of the wheel. If so that's going to be wrong, and it will look wrong. Again, Mustang pictures abound which showing the proper relationship. The reason I dwell on this is that this is sooooo easy to get wrong, especially if using the drawings like we do. Your use of a simple reinforced hole on the inside of the wing upper half for attachment of the gear strut, while a perfectly acceptable way to attach (a way most mass produced models are), it is entirely different from how the gear is attached in real life (of course), and therefore entirely different from the gear strut drawing. So this leaves it to the modeler to do alot of painstaking research into just how long the gear strut must be. I am not sure how you arrived at a strut length, but unless you did some equivalent of what I did above, the strut length has a high probability of being errant. I have the benefit of travelling this road already, so for me it is straight forward. Aw hell - I'll include some pics. This picture adequately shows how "long" the door is relative to the gear on a typical aircraft on the ground. Note the lower edge is just above the axle cap. And this picture shows the proper orientation of the door links (doesn't matter if it is a D model - it's the same for either). Note the slight downhill-outboard orientation of the links: You posted this pic back when you first put her on her legs: If the gear length in that pic is the same as now, and if the door length shown is the same as the beautiful doors you have just fabricated, then I am pretty sure your struts are too long (or less likely the doors are too short). Indulge me, and recheck Lopes Hope 1/18. This model of yours is absolutely magnificent - never seen anything like it. But do not screw this up! And with that, I will bow out, and wait for your continued acts of wizardry.
  3. JayW

    BIG HOG!

    Thanks for posting this. What a knock-em-dead F4U! I am currently building a 1/18 Corsair (from a 21st Century Toys model). It will take years. Been hard to get going (scratch building a P & W R2800 first). But your Big Hog has just added some motivation. I might do Big Hog too - it's going to be a 1A.
  4. I might be hurting rather than helping. I closely studied drawing 91-33106 Support Assembly - Landing Gear Pivot. That drawing puts the gear pivot point (intersection of gear pivot axis and centerline of gear oleo) at Wing Sta 69.346, dist above wing ref plane 0.9325 inch, dist forward of wing 1/4 chord 13.3125 inch. That drawing also shows local wing contour ordinates where I was able to determine (with the above ordinates) that the lower wing loft at the point where the gear strut protrudes is about 4.25 inches below the gear pivot point. Account for the 11 deg rake angle and you get 4.25 / (cos 11 deg) = 4.33 inches. From here, I can take drawing dimensions of the gear strut to arrive at the proper gear strut protrusion from the lower wing skin: Miss Velma has 1.07 inch protrusion of the upper strut to the lower wing skin (very close). Peter - I suggest you check Lopes Hope for gear upper strut protrusion relative to the lower wing skin. Should be 1.08 inch per above. If it is close, and if your gear door is an exact scale-down from the drawing (73-33302), then you can be assured the relationship between the gear strut and the door will be right. If not, then you will need to make some adjustment to the gear door length or strut length. Also note the 2.625 inch dimension above (from upper strut lower edge to door lug centerline). Scaled down to 1/18 and that is .146 inch. Check your door lug locations to that dimension. That way, assuming you have an accurate gear door, you can assure the orientation of the door links is right. So many Mustang efforts get this wrong. I will shut up now.
  5. Sorry Peter - I have to make a correction. Further inspection of drawing 73-33102 (LG strut assembly) show that under full compression, there is 1 29/32 inch of exposed compression strut oleo (not slammed down as I previously said). If you want to see this dimension, see zone A4. "... I think in length they are ok - the compression strut showing is 5.89mm and 0.2 inches os 5.09mm so its ballpark." you say. So if "static" extension is 1.5 inches from fully compressed, then static extension has 1.5 + 1.906 = 3.406 inches exposed oleo. Or in 1/18 scale - .189 inch. That equates to .189/.039 = 4.85 mm. That puts your 5.89 mm much closer to static.
  6. Well done. As a reminder main gear strut rake angle from vertical is supposed to be 11 deg. From the picture above (a stunning picture BTW - another one that looks like an actual aircraft), I measure 13 deg to that piece of thread, so if I measure right and the pic isn't distorted and the thread is indeed horizontal, then yeah - when gear are permanently installed, pull back on them a bit. As for door length - do enough arithmetic with dimensions provided on the drawings, and you can figure out the real life relationship between the door lower edge and the wheel hub in any one of the three defined extensions. From there, easy to define the relationship to your own extension (which is a good bit more than "static").
  7. Peter - check the two little lugs on the upper strut which are the attach points for the gear door links. They need to be 180 deg around (on the inboard side of the strut, not the outboard).
  8. Aha! For brake line installation see drawing 102-33401.
  9. Peter - your efforts on the MLG have yielded another shrink ray component(s). Honestly - I have seen so very many efforts by so many model manufacturers in 1/72, 1/48, 1/32, or 1/24 to represent the P-51 MLG struts, and nearly all fail to get the shape just right. Tamiya 1/32 seems the best. When I did my struts on Miss Velma in 1/18, I scribed the shape on blocks of plastic stock straight from the drawing (and I was thrilled to discover those drawings). So there was literally no guess work - all I had to do was accurately carve it out based on the scribe lines. But you have somehow arrived at what looks to be a dead-on accurate shape using formed metal parts brazed together. Amazing. I am also extremely impressed with the torque links. Those are very small parts even at 1/18 - I struggled with mine and didn't do a very good job. However even mine are way better than what one will find in a mass manufactured kit. Yours look wonderful. You will find the torque links lurk in the shadow of the wings and are not easily seen - but we know they are there, don't we? Also I am blown away by the wheel/tire assemblies. Those parts seem tailor made for 3d printing, and that is apparently the key. Congratulations. Now - in addition to the all important gear rake angle which we have discussed already, and which seems right to me based on your pictures, the relationship between the gear struts and the doors, IMO, is critical. Here again - most of the manufacturers get it wrong. It's a matter of length mostly. The problem, if there is one, usually arises when the wing thickness is inaccurate. This was an issue with both my 1/18 P-47 and my 1/18 P-51, and I had to take care to tweak the gear door length as required so that the lower edge of the door had the correct relationship with the wheel/tire. Of course, strut extension affects this relationship. Drawing 102-33001 defines three gear extension values - 44.727 inch fully compressed, 46.227 inch "static", and 52.727 inch fully extended. If one (correctly) assumes fully compressed has the lower and upper struts slammed down against one another, then fully extended exposes 8.0 inches of lower strut. And "static" position exposes 1.5 inches of lower strut. In 1/18 that is .44 inch and .08 inch. For Miss Velma I exposed about .18 to .20 inch, to depict an aircraft at something less than full gross weight. Wartime pics of P-51's show many aircraft with something like that extension. Your extension appears similar. Is it? Oh BTW - the lower extremity of the brake line attaches to a fitting on the brake drum. Lots of pics available. I am not sure it is defined on drawings though.
  10. Not that I have made any spectacular progress - I just want to stay in touch. Weather is turning cold and windy, and I am going to have more time to model. So if I confront the tedium of repetitious cylinder part making head on, I can get through this. I am not going to pursue 3D printing or resin molding here mostly because there are enough down sides to offset the upsides, and I kinda didn't want to anyway. Call me Styrene Man! The rings on the right are merely spacers, each to be put between the cylinder head and the basic body of the cylinder. The completed cylinder head you see in the center will sit on top of one of them. The eight parts on the left will sit on top of the intake lobes of the remaining eight cylinder heads. They have alot more good detail than their counterparts on the P-47 engine. Alot of carving and sanding.... The six little parts in the lower portion of the picture (looking like little turtle shells) are rocker arm covers and their almost microscopic attachment studs. I have two more to go at this stage (I'll need 36 total for the entire engine). I didn't do this at all for the P-47 engine. They are tough little buggers - I file them out of styrene half round stock that you can see there. So, I am nearly done with the intake side parts. Next will be the eight exhaust side parts, which are just as many parts. Then come the eight cylinder head cooling fin buildups. And then I will have nine of these: At that point, depending on my whims, I will either do the nine basic cylinder bodies for the front row, or do the nine cylinder heads for the aft row which are different from those of the front row. Ultimately I will have eighteen cylinders sitting around. Then it will be time to get out the lathe and machine the engine block parts. If you all didn't see that effort on the P-47, you will be in for a treat. This is going to be a much better engine than the P-47's. It will be a long project but the Corsair deserves a great engine. Happy Halloween!
  11. Wow - the finish line is almost in sight, non? I will want to see lotsa close-ups of that main gear!
  12. Just amazing how you get that metal sheet to behave. Well done.
  13. Yahoo!!! Awesome flaps my friend. Will you actually make a flap hinge? I did, and it was more trouble than it was worth IMO. But it did assure the flap was oriented correctly in the hole. Also, I am very interested in what you want to do at the fillet fairing. Flap actuation on the real airplane is accomplished by a hydraulic actuator in the fuselage under the floor (or under the radio racks). IT drives a torque tube (104-52608) that has an arm on either side which engages the flap drive fitting (which you have created so beautifully) via a push rod (either side). See 102-52001. This push rod (73-52622) is visible under the fillet fairing. I did a lousy job with that push rod on Miss Velma. But at least it is represented. Wondering what your plan is.
  14. Corsair. Mmmmmmm. I'll be watching. I am doing a -1A in 1/18 scale, will be done sometime this century.
  15. Peter - I did not see any pics of the underside of the aileron. Did you do the tab control rod and associated bracketry? Control rod is 102-52577, next higher assembly wing install 102-10001.
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