Wed 21st Nov 2hr 20
Completed R-918 attach strips, fitted and match-drilled them to R-901 skins and R904. Disassembled the rudder and began "DDEP" (Deburr, Dimple, Edge preparation)
Ken Scott replied to an email I had sent Yesterday to Vans support. He says I should replace the HS-902 spar on which some of the countersinks are too deep but the others three spar halves can be used. He also suggested two additional rivets through the skin and stiffeners either side of the double-holes created by mistake when dimpling the stiffeners. I don't like this as I believe the eye will be drawn to the anomaly in the rivet pattern. However the part is very cheap and as I am having a HS-902 shipped across anyway, there will be no additional postage or packing charge. Once they arrive, I can completely eliminate that ding. I also copied my examiner Mick Bevan on this correspondence and he concurs.
Yesterday evening was also the monthly meeting of the SAAC. I always bring a notebook along to record all the useful information and contacts that I get. Yesterday, I got a lead on a torque screwdriver that can handle the very low torque values necessary for the AN3 bolts in the central HS hinge brackets - 20-25 inch pounds. Charles O'Shea also took me through the builders manual that I will be completing with Mick Bevan.
I had already cut the bottom attach strips to length as they come from the same piece as the R-917 shim. As George Orndorff recommends, I cut the two R918 attach strips from the ends of this piece, leaving more than enough for the R917 in the middle. This evening, I cut off the angled ends that butt up to the rudder brace and filed and polished the edges.
They are held in place initially with side-jaw clecos (you need the longer 1" type to reach) and then clecoed as the holes are drilled. The lower holes are not drilled at this stage. The plans simply specify "2" approx spacing" - one of the few places I have seen the abreviation "approx" anywhere on these plans.
Taking the rudder apart took a while as there were so many clecos but that is because I had the stiffners clecoed in as well. I also deburred the skins very lightly.
No photos this evening - The camera is acting up and just could not be persuaded to perform.
Showing posts with label Vans RV-9. Show all posts
Showing posts with label Vans RV-9. Show all posts
Main Rib Edge Preparation
Thurs. 1st November 2007 3hr 35min
Filed, deburred and polished the edges of the 10 HS-904 main ribs. Checked and adjusted the flanges for square. Fluted the ribs until straight.
Another evening of relative calm. Harry Hopkins had laid great emphasis on edge preparation in the metalworking course I took with him back in July and I was determined to get it right. I used the magnifying lamp pictured here to ensure that I was getting a good surface.
In the main, it went well but there are two very narrow notches, top and bottom, separating the main part of the flange from a tab that goes under the flange of the forward spar. These lead back to a relief
hole on the actual web and they are so narrow that they are very hard to polish. I got a small file in okay but it was nearly impossible to get at them with the scotchbrite wheel. a small sanding wheel on my Dremel might have done it but I was reluctant to try. I felt I was more likely to increase rather than decrease the chances of creating a weak point where a stress tear might begin so I eased off on the filing in this area. I think the best solution would be to use a sheet of fine abrasive paper folded to give me a profile to match the notch.
I found the 1 inch Scotchbrite wheel on the die grinder invaluable for polishing the edges of the lightening holes but I used the big wheel on the bench grinder for all the rest.
Were it not for the novelty of the project as a whole, this process would have become quite boring. My shoulders ached at the end of quite a long session.
Filed, deburred and polished the edges of the 10 HS-904 main ribs. Checked and adjusted the flanges for square. Fluted the ribs until straight.
Another evening of relative calm. Harry Hopkins had laid great emphasis on edge preparation in the metalworking course I took with him back in July and I was determined to get it right. I used the magnifying lamp pictured here to ensure that I was getting a good surface.In the main, it went well but there are two very narrow notches, top and bottom, separating the main part of the flange from a tab that goes under the flange of the forward spar. These lead back to a relief
hole on the actual web and they are so narrow that they are very hard to polish. I got a small file in okay but it was nearly impossible to get at them with the scotchbrite wheel. a small sanding wheel on my Dremel might have done it but I was reluctant to try. I felt I was more likely to increase rather than decrease the chances of creating a weak point where a stress tear might begin so I eased off on the filing in this area. I think the best solution would be to use a sheet of fine abrasive paper folded to give me a profile to match the notch.
I found the 1 inch Scotchbrite wheel on the die grinder invaluable for polishing the edges of the lightening holes but I used the big wheel on the bench grinder for all the rest.Were it not for the novelty of the project as a whole, this process would have become quite boring. My shoulders ached at the end of quite a long session.
HS Aft Spar
Wed. 31st October 1hr 30min
Clecoed the two HS-903 aft spar halves together with the HS-906 aft spar doubler and match drilled. Clecoed on the eight HS-912 outboard hinge brackets and match drilled.
Calm returned this evening. After the discouraging mess-up yesterday, I had decided to take an evening off but my wife was out at her French class so, as she couldn't benefit from my company, I decided that it would be better to get straight back into the saddle. This piece of work was a good choice as it simply couldn't go wrong. And so it turned out.
The powder coating on the hinge brackets looks great so I don't think I will be painting them. The coating makes getting a 3/32 cleco into the holes somewhat difficult but a 1/8 won't hold them.
Clecoed the two HS-903 aft spar halves together with the HS-906 aft spar doubler and match drilled. Clecoed on the eight HS-912 outboard hinge brackets and match drilled.
Calm returned this evening. After the discouraging mess-up yesterday, I had decided to take an evening off but my wife was out at her French class so, as she couldn't benefit from my company, I decided that it would be better to get straight back into the saddle. This piece of work was a good choice as it simply couldn't go wrong. And so it turned out.The powder coating on the hinge brackets looks great so I don't think I will be painting them. The coating makes getting a 3/32 cleco into the holes somewhat difficult but a 1/8 won't hold them.
Day one, page one
29th October 2007 1hr 30min
Assembled the HS-902 forward spar halves and HS-907 forward spar doubler, match-drilled them. Fabricated the HS-908-L&R attach angles.
After 18 months of planning and over three months of hard work on the shop, I finally got started on building the plane today. What a let down! I had just come from a chastening experience on building the Vans Training Project, so I was aware how important it was to read the plans carefully. Despite this, I really messed up and find myself today ordering a replacement part from Vans.
Step one was to cleco and match-drill the doubler plate to the two forward spar channels. Right away, I couldn't reconcile the instruction to cleco the positioning hole in the attach angles to the ONE matching hole in the appropriate position on the spars. It seemed to me that there were two matching holes, not one. I scratched my head for fully 10 minutes before realising that, while the spar halves are identical left and right, they are not symetrical top and bottom and the one matching hole was on the edge facing away from me. If it takes a similar length of time to figure out other simple instructions like this, I better plan on an eight-year build instead of four-years.
Then I came to make the actual attach angles. Completely failing to read the plans properly, I marked out the first one to the finished width of 1 21/32 inches, and marked an angled line from this point on the edge of the section back to the narrower dimension of 1 1/2inches for the vertical back plate AND CUT IT! Then I realised that the flange is too long and needs to be shortened back to 1 5/32. When I did this, because the part narrows as it goes back along this angled line, the width at the new edge is now shorter by 1/8 inch. Clearly, this will not give me the designed edge distance for the fasteners that go into this horizontal flange. Whether or not it will give me enough edge distance, I was simply too sick to go and measure. Either way, I am not happy with it.
Not content with that, I noticed that the height for the vertical flange of the angle comes really close to the rounded lip of the angle stock. In fact, shortening it back to the designed height would not fully remove the rounded edge profile of the original section. Now it hits me that the original section has flanges of differing depths. It is 2in X 2 1/2 in and I attempted to cut the longer flange of the attach angle from the shorter flange of the angle stock! By now, I am thinking of putting a shot of my best Irish single malt whiskey in my coffee (a once-in-a-decade event) while I try to calm down. It was the nausea that prevented me from wasting good whiskey. I went ahead and finished the part anyway, just for the experience but I am certain it won't pass muster and will have to be redone.
Anyway, picking myself up, I moved on to the second angle. This time I marked it out correctly and cut it on my new band saw with plenty of allowance for smoothing. Maybe a little too much allowance because I am tempted to go back and take a little more metal with the saw. Working by hand with no guide fence this time, I get too close to the line at one point near the ? Disaster! In order to get a straight line, I have to remove all the metal down to the same closest point using a file but when I do, I am on the line and there is still a gouge mark to be removed so I have to take out the line itself, which I marked up in such a way that it needed to be left on the metal. When I remove this gouge, the part sits within the lines on the plan and is about 1/64th too small. Perhaps this is not critical on its own but, combined with the 1/8th error on the other attach angle, there is no getting away from the fact that I have to make a replacement set.
The most upsetting part of this is that my confidence in my workmanship is badly shaken and for the first time, I am beginning to doubt that I can produce the necessary standard. As a result, I have decided that I am going to firstly take a night off and get plenty of sleep (I think tiredness may have been a contributory factor). Secondly, I am going to constantly read and re-read the relevant section of the manual as I go on with the work. I keep a photocopy of the manual with the small preview plans in the office so I can look over them at lunchtime. I will underline each instruction in the manual immediately before I carry it out as well as every part number, material and fastner call-out, note, etc on the relevant plans pages. Finally, I am going to experiment with a clearance of about 3/64th outside the marked dimension when I am making cuts. The original clearance I used on the attach angle was closer to 3/32, which was a bit too much for finishing though, as it turned out, far too little to be removed with a band saw.
So today (30th Oct) I found myself on the Vans website ordering a replacement 5 inch length of angle. It only costs $5.90 and should be easy to ship. To maximise the use of the shipping cost, I also ordered some riveting tape that I wished I had bought at the beginning and I included the smallest quantity of tank sealant available, for use on the trailing edges of the HS and rudder
Assembled the HS-902 forward spar halves and HS-907 forward spar doubler, match-drilled them. Fabricated the HS-908-L&R attach angles.
After 18 months of planning and over three months of hard work on the shop, I finally got started on building the plane today. What a let down! I had just come from a chastening experience on building the Vans Training Project, so I was aware how important it was to read the plans carefully. Despite this, I really messed up and find myself today ordering a replacement part from Vans.
Step one was to cleco and match-drill the doubler plate to the two forward spar channels. Right away, I couldn't reconcile the instruction to cleco the positioning hole in the attach angles to the ONE matching hole in the appropriate position on the spars. It seemed to me that there were two matching holes, not one. I scratched my head for fully 10 minutes before realising that, while the spar halves are identical left and right, they are not symetrical top and bottom and the one matching hole was on the edge facing away from me. If it takes a similar length of time to figure out other simple instructions like this, I better plan on an eight-year build instead of four-years.Then I came to make the actual attach angles. Completely failing to read the plans properly, I marked out the first one to the finished width of 1 21/32 inches, and marked an angled line from this point on the edge of the section back to the narrower dimension of 1 1/2inches for the vertical back plate AND CUT IT! Then I realised that the flange is too long and needs to be shortened back to 1 5/32. When I did this, because the part narrows as it goes back along this angled line, the width at the new edge is now shorter by 1/8 inch. Clearly, this will not give me the designed edge distance for the fasteners that go into this horizontal flange. Whether or not it will give me enough edge distance, I was simply too sick to go and measure. Either way, I am not happy with it.
Not content with that, I noticed that the height for the vertical flange of the angle comes really close to the rounded lip of the angle stock. In fact, shortening it back to the designed height would not fully remove the rounded edge profile of the original section. Now it hits me that the original section has flanges of differing depths. It is 2in X 2 1/2 in and I attempted to cut the longer flange of the attach angle from the shorter flange of the angle stock! By now, I am thinking of putting a shot of my best Irish single malt whiskey in my coffee (a once-in-a-decade event) while I try to calm down. It was the nausea that prevented me from wasting good whiskey. I went ahead and finished the part anyway, just for the experience but I am certain it won't pass muster and will have to be redone.
Anyway, picking myself up, I moved on to the second angle. This time I marked it out correctly and cut it on my new band saw with plenty of allowance for smoothing. Maybe a little too much allowance because I am tempted to go back and take a little more metal with the saw. Working by hand with no guide fence this time, I get too close to the line at one point near the ? Disaster! In order to get a straight line, I have to remove all the metal down to the same closest point using a file but when I do, I am on the line and there is still a gouge mark to be removed so I have to take out the line itself, which I marked up in such a way that it needed to be left on the metal. When I remove this gouge, the part sits within the lines on the plan and is about 1/64th too small. Perhaps this is not critical on its own but, combined with the 1/8th error on the other attach angle, there is no getting away from the fact that I have to make a replacement set.The most upsetting part of this is that my confidence in my workmanship is badly shaken and for the first time, I am beginning to doubt that I can produce the necessary standard. As a result, I have decided that I am going to firstly take a night off and get plenty of sleep (I think tiredness may have been a contributory factor). Secondly, I am going to constantly read and re-read the relevant section of the manual as I go on with the work. I keep a photocopy of the manual with the small preview plans in the office so I can look over them at lunchtime. I will underline each instruction in the manual immediately before I carry it out as well as every part number, material and fastner call-out, note, etc on the relevant plans pages. Finally, I am going to experiment with a clearance of about 3/64th outside the marked dimension when I am making cuts. The original clearance I used on the attach angle was closer to 3/32, which was a bit too much for finishing though, as it turned out, far too little to be removed with a band saw.
So today (30th Oct) I found myself on the Vans website ordering a replacement 5 inch length of angle. It only costs $5.90 and should be easy to ship. To maximise the use of the shipping cost, I also ordered some riveting tape that I wished I had bought at the beginning and I included the smallest quantity of tank sealant available, for use on the trailing edges of the HS and rudder
The Training Project
I included the Vans training project with the order for my empennage and yesterday, having declared the workshop finally ready (not "finished", mind you), I got to work on the project at last.
The project has two elements; a section with two plates and an angle that have to be rivetted together and a short section of a mock aerofoil comprising channel section spar, reinforcing plates, ribs at each end, four stiffners, top and bottom skins, which are curved and pop-riveted at the leading edge like a typical rudder and double-flush rivetted through a wedge extrusion at the trailing edge. The whole thing measures about one foot square when finished.
The instruction say "if the finished project ends up with various dents, holes and other fumbles. . . good! It means you haven't been afraid to try and you are making your "beginners mistakes" here instead of on the actual airplane". Well, I'm glad they said that because otherwise, I would be profoundly depressed today. I can't get over how many mistakes I made. Mainly for my own benefit, here's a list of the main ones:
1. Not reading the plans fully. I put all the stiffners in facing outboard, with the result that the top and bottom flanges were meeting when the section was fully assembled. I drilled two of them out and switched them - unacceptable on a flying aerofoil in my view, as they had been match-drilled to different positions on the skin. However, it demonstrated the exactness of the matched hole system as the stiffners sat perfectly in their new positions. I also missed the fact that the reinforcing plates on the spar were to be fastened with size 4 universal head rivets and did not need to be dimpled. I actually resorted to using flat heads in the dimpler to fix this one by flattening out the dimples. I imagined that far away in Aurora, Oregon, a very distinguished kitplane manufacturer was wondering why he had a sudden urge to cringe! Sorry Mr V. On an actual airplane, that would have meant replacing the spar. I also managed to misread the rivet call-out for the first section of the project and put a universal head into a dimpled hole intended and already dimpled for a countersunk head rivet. At least, I am now quite practiced at drilling out rivets and I do not believe I damaged any of the holes while doing this - a skill that will be used extensively, I am beginning to realise.
2. Deburring holes to be dimpled. The Isham inc. 'manual' makes the case that deburring is over emphasised in the homebuilt community. You can see the effect of deburring very clearly on the underside of a dimple because an edge that should be nice and sharp is clearly 'shaved off' when that edge is turned up and formed into the sharp end of a 'funnel', as in a dimple. This robs effective depth from the finished metal. I have decided to look for a gentler way of removing obvious burrs from holes to be dimpled and leave it at that.
3. Bad rivetting. I encountered every sort of problem with rivetting. I have under-driven rivets, over-driven rivets, slanted heads, off-center heads and hardly a universal factory head without a 'smiley' grinning stupidly back at me. I also seem to have let the mushroom set float off two bucked skin rivets, leaving a slight dent in the skin beside the factory heads. Like I said, I am now very experienced in drilling out these offending examples. I don't even know what I did wrong in some cases. As most riveting is done either in the horizontal or vertical planes, I thought of getting tiny spirit levels to glue to the top, side and 'breech' of my gun as a guide to lining up the gun properly until I can judge it better by eye. One fault (slanted heads) was not really my fault. It happens when back rivetting close to stiffners. The white plastic collar on the back rivet set is quite thick and when the angle used for stiffners is small and the holes are close to the web, it prevents the actual head from sitting squarely on top of the shank. As rivetting progresses, it slides off, leaving a head shaped like a ski jump. Holding the collar firmly with my free hand improved things but I think I will grind off a flat section on one side of this collar when I encounter similar small angles in the elevators.
4. Poor drilling. I managed to get an elongated hole in the trailing edge wedge. This happened while using a drilling guide to achieve the correct angle. Maybe I was concentrating too much on the guide.
I didn't have all the materials available (who has mild steep plate, hardwood blocks and bits of 4 X 2 lumber knocking about the place?) so the project is not yet finished. I can see that the bucking/dimpling bar that I am supposed to make from the steel plate will be necessary on every small rib so I will go to the trouble of making it exactly according to plans. I simply improvised the rest.
All in all, it was quite a chastening experience and far from the simple limbering up exercise that I thought it was going to be. Hopefully, it will turn out to be the best $35 that I will spend on the entire project.
The project has two elements; a section with two plates and an angle that have to be rivetted together and a short section of a mock aerofoil comprising channel section spar, reinforcing plates, ribs at each end, four stiffners, top and bottom skins, which are curved and pop-riveted at the leading edge like a typical rudder and double-flush rivetted through a wedge extrusion at the trailing edge. The whole thing measures about one foot square when finished.
The instruction say "if the finished project ends up with various dents, holes and other fumbles. . . good! It means you haven't been afraid to try and you are making your "beginners mistakes" here instead of on the actual airplane". Well, I'm glad they said that because otherwise, I would be profoundly depressed today. I can't get over how many mistakes I made. Mainly for my own benefit, here's a list of the main ones:
1. Not reading the plans fully. I put all the stiffners in facing outboard, with the result that the top and bottom flanges were meeting when the section was fully assembled. I drilled two of them out and switched them - unacceptable on a flying aerofoil in my view, as they had been match-drilled to different positions on the skin. However, it demonstrated the exactness of the matched hole system as the stiffners sat perfectly in their new positions. I also missed the fact that the reinforcing plates on the spar were to be fastened with size 4 universal head rivets and did not need to be dimpled. I actually resorted to using flat heads in the dimpler to fix this one by flattening out the dimples. I imagined that far away in Aurora, Oregon, a very distinguished kitplane manufacturer was wondering why he had a sudden urge to cringe! Sorry Mr V. On an actual airplane, that would have meant replacing the spar. I also managed to misread the rivet call-out for the first section of the project and put a universal head into a dimpled hole intended and already dimpled for a countersunk head rivet. At least, I am now quite practiced at drilling out rivets and I do not believe I damaged any of the holes while doing this - a skill that will be used extensively, I am beginning to realise.
2. Deburring holes to be dimpled. The Isham inc. 'manual' makes the case that deburring is over emphasised in the homebuilt community. You can see the effect of deburring very clearly on the underside of a dimple because an edge that should be nice and sharp is clearly 'shaved off' when that edge is turned up and formed into the sharp end of a 'funnel', as in a dimple. This robs effective depth from the finished metal. I have decided to look for a gentler way of removing obvious burrs from holes to be dimpled and leave it at that.
3. Bad rivetting. I encountered every sort of problem with rivetting. I have under-driven rivets, over-driven rivets, slanted heads, off-center heads and hardly a universal factory head without a 'smiley' grinning stupidly back at me. I also seem to have let the mushroom set float off two bucked skin rivets, leaving a slight dent in the skin beside the factory heads. Like I said, I am now very experienced in drilling out these offending examples. I don't even know what I did wrong in some cases. As most riveting is done either in the horizontal or vertical planes, I thought of getting tiny spirit levels to glue to the top, side and 'breech' of my gun as a guide to lining up the gun properly until I can judge it better by eye. One fault (slanted heads) was not really my fault. It happens when back rivetting close to stiffners. The white plastic collar on the back rivet set is quite thick and when the angle used for stiffners is small and the holes are close to the web, it prevents the actual head from sitting squarely on top of the shank. As rivetting progresses, it slides off, leaving a head shaped like a ski jump. Holding the collar firmly with my free hand improved things but I think I will grind off a flat section on one side of this collar when I encounter similar small angles in the elevators.
4. Poor drilling. I managed to get an elongated hole in the trailing edge wedge. This happened while using a drilling guide to achieve the correct angle. Maybe I was concentrating too much on the guide.
I didn't have all the materials available (who has mild steep plate, hardwood blocks and bits of 4 X 2 lumber knocking about the place?) so the project is not yet finished. I can see that the bucking/dimpling bar that I am supposed to make from the steel plate will be necessary on every small rib so I will go to the trouble of making it exactly according to plans. I simply improvised the rest.
All in all, it was quite a chastening experience and far from the simple limbering up exercise that I thought it was going to be. Hopefully, it will turn out to be the best $35 that I will spend on the entire project.
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