Visitor #since 15 March 2002
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Equipment - Yes, I want to build my Seats,
12/31/06. The ride I got in Howard's RV-7A was
with his Oregon Aero seat cushions that he had just received, so I
got to help "test" them out. I was pretty sure I was going to like
them. I had already decided that I was going to build my own seat
cushions using Confor foam from
High Tech
Foams . But sitting on them in a plane for a flight
instead of a pavilion at The first seat I
build will be similar to that shown in my first Paint drawing. The
only thing I'll do is move the bend point circled in red forward a
little. I'll build one seat, my wife's, after I get my canopy done
so that I can get some serious sit time (reading) and adjust the lumbar
support to fit the back that goes with my 6'5" body. (Before I
finally glue the seat layers together, I'll optimize the lumbar for my
wife's 5'0" body. I'll have to build her a booster.) I may find
that I need to reduce the thickness of green foam under my behind to keep
from my headset from hitting the canopy. If so I'll do that when I
build my seat cushions. |
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Equipment CHANGE - Bob Archer COM Antenna, 11/02/06. My friend Howard finished his RV-7A this summer and I got my first-ever ride in ANY RV on November 1st. (This was after having already invested 3,400+ hours and $$$.) The only squawk I had was the air-to-ground communications, which I have to believe are the fault of the antenna. Not necessarily the antenna per say, but the combination of the antenna and the wing tips they are installed in on a stock RV-7A. When Bob's antennas started getting used in side-by-side seating RVs, it was the RV-6, which had wing tips that went out parallel to the top surface of the wing. So, the antenna mounted in that wing tip had a pretty decent vertical orientation - key for a COM antenna. But the RV-7 wing tips design is neither "swept" up or down, so there's much less opportunity to mount the antenna with as much vertical orientation. For me that lack of vertical orientation became obvious when we were within site of Detroit City Airport over Canada and could not get the tower to acknowledge us. Going back and reading an email from Bob Archer on the subject:
I've gotta believe that the 50 mile ATIS guy was in something with upswept tips. In any event, I was not satisfied with what I saw of Howard's COM ability. I'd like to get an IFR rating and I don't want to have to fly in circles to communicate. The antenna in the picture that is fully visible has the longer "wing" and is thus the VOR antenna. I'll install that. But I'll probably go with a bent whip belly antenna for COM. My advice: before you commit to this antenna for COM and drag reduction, get a ride in a plane that has it installed in wing tips similar to yours. |
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Status - Thermoplastic Nature of LIFE, 5/16/06. As you can see, it's been almost a year since I've posted any progress. I can't believe it myself! I was just getting into the fiberglass as noted below, and I'm pretty sure at this point that I'll never want to build a fiberglass airplane or boat for that matter. But that's not really what put the binders on my progress. I was facing the outsourcing/layoff dilemma most of last year, and once I was told I was "not on any layoff list", I still felt like I had lost financial steam, at least for big purchases. So, I committed to work on the multitude of tasks that were there that did not require thousands of dollars to move forward. But even that didn't really get me going. I haven't lost hope, but I sure as hell have lost high hope. About a month ago, my wife decided she wanted to put up some fresh paint in the living and dining rooms. That snowballed into - (me) there's no point doing that since we haven't insulated the outside walls - might as well blow in some insulation between these old plaster board and brick walls. More snowballing: We've got to do all the electrical work that we would want such as recessed outlets behind pictures so the funky looking cords don't hang down, etc. etc., because once we insulate, we won't fishing any new romex up through that stuff. It goes one from there - finish the kitchen, pantry, window moldings, etc., but you get the point. So, I've embarked on a job that will involved dragging my wood working tools out to the garage from the basement, and moving the fuselage up against the wall of the garage... Did I mention the furniture I want to build... I hope I'm not away from the plane too long, and I hope I come back to it real hungry to work on it. | |
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Progress/Tip
- Thermoplastic Nature of Fiberglass, 5/21/05. Fiberglass
is mostly new to me, so I'm not as confident. The rudder top fairing
so far has been the only piece to be too narrow. It needs to press
out against the rudder skin if you're going to do a good job of riveting
it. The construction manual says it can be reformed by dipping in
very hot water or with a hair dryer or 'carefully' with a heat gun.
But how to hold it in the desired position while it cools was left unsaid.
Shown in the picture is my solution. It worked well
with a heat gun.
I asked Ron Walters, one of our chapters tech advisers who recently completed his 2nd Glasair IIRG to come give my project a once over, but really I was after his fiberglass experience. Two key things I got from Ron. One, using a 'parting agent' works best for releasing fiberglass parts from molds. Wax can be used, but it absolutely cannot have any hint of silicone in it. Can't remember the reason, but given's been working with fiberglass making model parts for Chrysler for years, I'll take it as gospel. A parting agent costs about $8 a pint at your local fiberglass shop. I'm going about making my end caps a little differently than Van suggests. I'm going to bend some acetate over a curve that matches the radius of the elevator/rudder, and lay up and epoxy some glass on that curve. Then I'll tack bond a concave piece to the stabilizer fairing and a convex piece to the control surface fairing while they are clecoed in place. That will hold the opening to it's proper dimension while the cap bond dries. This should give me a nice uniform gap throughout the range at which they will pass each other. After the cap bond dries and I take the piece off to finish the inside layers that are called out for in Van's instructions, then the 2nd thing Ron suggested was to make a 3/16" to 1/4" radius fillet in the corner with epoxy and microballoons and let it dry. Then lay in some glass cloth. The glass will not have to make a sharp turn as it would without the fillet, which will make it easier to lay up without entrapping air, and it will make a stronger joint since fiberglass, like aluminum, is more prone to stress fractures at sharp bends than ones with appropriate radiuses. |
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Progress/Mistake
- Jigging Tail Feathers, 4/30/05. Last month I was
working (diligently) on the canopy, but screwed up the C-702, and decided
to order a new one from Van's as a template and stock to make my own.
(See mistake, 3/28/05.) So with the current C-702 now scrap, I
decided to make my life easier and trim off the lip between the front row
of rivets (clecos yet) and the forward deck skin, so that I could easily
see the gap between the front canopy bulkhead and the angle to which is
affixed the forward canopy weather seal. That made that job a lot
easier, but what I discovered was that somehow I managed to drill the
joiner plate for the front canopy bulkhead with a slight dip in the
center. This explained to me why when I was testing opening my
canopy with the skin on, the skin was going forward to catch the front
deck skin. It was because the center section of the canopy skin was
slightly bowed up because the bulkhead top which it was clecoed was bowed
down. So, as I'd raise my canopy, that forward lip of the canopy
skin, instead of raising was unloading or unbowing, but was not raising,
and was moving toward the front deck skin. Bottom line decision for
me is that I'm going to have to shim this section of the canopy skin, so
that it begins to lift as soon as the canopy begins to lift. And
I've decided I do not want to do that until the front deck skin is riveted
in place and NOT moving. The domino effect now puts me into a
position where I'll need to completely wire everything I intend to have
under that front deck, which means the easiest way to insure that I don't
forget something is to completely install my IP and ALL connections
through the firewall. Since I'm 90+% certain I'm going to be laid
off in the next few months, now is not the time to spend $$$. So,
there's PLENTY of work to do on the plane without spending very much money
at all, so that's the plan for now - I've been installing and jigging the
tail feathers during April.
I finished up the elevators last night with the push-pull tube in place. The elevator deflection limits called out for are 25-30 degrees up and 20-25 degrees down. I got 27.7 up and 24 down. I could have maxed out both, but in the case of "up", I would have had to grind off part of the aft elevator horn to keep it from hitting the aft bulkhead. No need for that - I'm close enough to "maximum" control to suit me I'm sure. I did goof up the F-781 attach plate for the front spar of the vertical stab. Late at night I assumed that after drilling and clecoing one hole all I needed to do was align the top portion of the plate to the front spar of the horizontal stab with a 90 degree triangle. I didn't realize the top portion of the plate was slightly tapered. Damn! One of the four AN3 bolt hole edge distances was sub-par, so $5 gets me a new one. I'm going to work on all the fiberglass for the tail, finish the install of the vertical stab and rudder, and then move on to jigging the wings and all of their fairings and wing tips, lights, strobes, etc. Grousing: See 'Progress - Forward Spinner Bulkhead Spacer, 2/15/05' for complaints about Van's support. |
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Progress
- Canopy Lift Strut Hinge Points, 3/29/05. I have a
concern for the design of things that are subject to torque and off-center
forces. The forward hinge point is shown on the blueprints with two #10 machine
screws. The force of the lift strut is about 1" off-center
of where the ball stud is attached to the canopy frame. My gut tells
me that this point may be prone to early wear. I made my block with
a third screw attach point - not in line, but in a triangle. Also,
had I thought it through, I would have realized that the tapped hole for
the ball stud would need to be countersunk about 1/16" since the
threads on the stud do not go all the way to the nut. What comes
with the lift strut kit are thin washers. You could use thicker
washers, which would just increase the torque arm making the 'bad' forces
on your canopy frame worse, or you could countersink the hole just enough
so that with a thin washer, the ball stud can be screwed all the way
in. I would suggest that 1/16"countersink BEFORE you tap the
hole for threads. I think it'll be cleaner in the long run.
Similar deal with the rear attach point, so the stable triangle again. For some reason, I was worried about the relatively thin material of the canopy rail. I considered riveting a doubler (or two) behind the rail to provide a thicker stock for the bolt shafts. I just now realized that the plans call for MS24693S51 non-structural screws, which have threads all the way to the countersunk head, instead of MS24694 structural. I know it's not "structural", but I can't see any good reason to put threads through that thin material in the canopy rail where it would, I think, stand a greater chance of elongating the holes compared to a structural bolt. |
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Mistake
- Canopy Frame/Side Rail Junction,
3/28/05. Not looking enough at the blue prints and
'thinking' I had a handle on the objective... Shown in the left of
the picture between the canopy and the side rail is an 1/8" piece of
hard rubber "packing" material that you can buy at Home Depot in
the plumbing department. I figured it'd be great as the 1/8" spacer without
scratching my paint job. My problem was that I put one under the
rear of the frame - about where the ruler is at and then started filing
the C-702 forward canopy skin to fit to the canopy rail. I got a
good fit and when I started fitting the C-613 slice between the canopy
frame and the side rail, I realized that my C-702 would now be too
short. The gap at the front was a little wide right out of the box,
so instead of ordering a new C-702, I ordered a piece of 0.025"
aluminum from Van's and I'll make my own. It should be here
tomorrow. And since I had dimpled my C-702 I was worried that it
would not make a good template, so I ordered a new C-702 as well. In
for a penny, in for a $100,000!
So far this is the only sheet metal that doesn't fit properly and can't be made to fit. Not the prepunched holes although positioning along the row of rivets near where the C-702 butts up against the cockpit rail was kind of goofy. (I will not drill that bottom row when I use the new C-702 as a drill jig - I'll back drill them with the skins held down with ratcheting cargo straps.) Shown in the second photo is a brand new C-702 straight from Van's. I just clecoed it into position, and as you can see in the pic, I'm almost an 1/8" short at the position shown and its getting worse. Worse still, the edge continues straight, while the aft two inches of the C-702 should follow the longeron as it bends down (level), so the gap gets even worse. It seems from photos of other tip ups, there's a visible gap in this area, although I don't think what I've seen is a bad as what I have, and I believe I've done everything else correctly. In any event, I spent this last day of March drilling holes through a new sheet of 0.025" X 16" X 50" I ordered from Van's using a new C-702 as a drill jig. Tomorrow I'll really use those aviation snips I bought with my Avery tool kit and "almost" make an airplane part from raw materials. I'll make the edge shown anywhere from 1/32" to 1/4" longer and fit it to a primed and riveted frame sitting on 1/8" hard rubber spacers. One other thing that kind of blows my mind. Both of the prepunched holes shown in the lower picture coincide closely with either rivets in the C-613 slice plate of the fitting into which the ball stud attached to the canopy frame for the forward pivot of the canopy gas lift strut. I'll skip drilling them as well when I use the new C-702 as a drill jig and drill them from the inside of the canopy frame clear of any other rivets or fittings. |
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Tip
- C/S Prop Blade Cutouts in Spinner, 3/3/05. The
paper chase below was helpful, but I still felt most comfortable starting
with a pin template and fitting and rotary filing repetitively. To
do this I needed to be able to set the blades to full pitch by
myself. So, the prop is bolted to some hardware store steel
angles. The base of the prop was protected with duct tape.
Then the angles were clamped to the bench. Now the prop is
immobile. Next, to get some leverage, I took my pin template maker
and formed it to the forward face of the blade. The back face is
essentially flat. With the appropriate cutout in my 2X4, and the
blade wrapped in masking tape, followed by some closed cell packing
material, followed by some duct tape, I clamped my "wrench" onto
the prop. Worked like a charm.
This "tip" is less of a tip and more of a heads-up. Hartzell says that in addition to the spacers provided for the aft bulkhead, at most 2 washers can additionally be used between the bulkhead and the prop. I used two simply to minimize the thickness of the spacer I needed to make for between the prop dome and the forward bulkhead so that I could get a snug fit with the spinner fore and aft. At the time I was doing that I had no idea how close the trailing edge of the prop would come to the aft spinner bulkhead at full pitch. I was lucky. As you can see in the second picture, the trailing edge cutout is about 1/32" below the forward face of the aft bulkhead. Had I used only the supplied spacer and no washers, I strongly suspect that the trailing edge of the blade would have contacted the aft bulkhead at full pitch. So, Heads Up! |
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Tip
- C/S Prop Blade Cutouts in Spinner, 2/21/05. Marking
and making prop blade cutouts in your spinner is easy enough if you've got
a fixed pitch prop. It's still easy enough for the flat pitch
condition of a constant speed prop - the kind we use - not the kind for
turboprops that feather the other way. But taking a template measurement
with your pin template maker (hardware item) is not going to be easy,
because even though Brad at Hartzell says the return spring is not very
strong and two guys can twist the blades to full pitch - it really does
take two men, and one of them will not easily be able to hold the prop at
full pitch while the other sets the pin template maker. By the way -
if you try this, temporarily take out the orange plug from the back of the
prop since twisting to full pitch creates a serious vacuum that you're
trying to overcome in addition to that not-so-strong spring!
My solution: you can figure out where the center of the prop spindle is. The case break point is on the diameter and the center is halfway between the hole opening. Take your templates you can make from the comfortable flat pitch position and rotate the "blade" through the maximum pitch change the prop can make. I measure about 30 degrees stop to stop. There's your full-pitch template. Of course you will have to verify 1/16" to 1/8" clearance after everything is fit by manually twisting the blades. But, if you overshoot on the full-pitch cutout, no one is ever going to see that your gap is bigger than 1/8". Just make sure you have a nice even fit at flat pitch, which is what everyone at Oshkosh will be able to notice. |
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Tip
- Drilling the Front Spinner Bulkhead, 2/20/05. I
have plenty of experience measuring things very accurately and then being
amazed at how far off I am in the end! I hate that feeling of
ineptitude. Since my polished spinner is to me one of the focal
points of the plane, I wanted to get it right, and I have that nagging
history of "measure failure". So, my solution was to mark
my drill points on the front bulkhead, not the spinner. I accurately
made marks every 60 degrees such that two of the six holes made a line perpendicular to the axis of the prop blades - makes it look like you gave
it some forethought and exercised some control over the situation. I
then took a 2X4 and screwed a 4X4 door hinge to one end, set it on the
bench, and laid the other end
flush with the face of the bulkhead - without the spinner on. Then I
marked on the 2X4 where I'd drill a hole in the drill press so that it
went 90 degrees through the wood and would line up with the middle of the
bulkhead flange.
Now, without the spinner on, put a loose drill bit through the hole and line it up on one of the six marks to be drilled in the bulkhead, and then clamp the loose end of the door hinge to the bench. Double check that your still on the mark after you tighten the hell of out the clamp, and pivot the 2X4 out of the way. Slide the spinner on and hold it down for a snug fit against the bulkhead, pivot the 2X4 against the spinner and drill away! Now for my mistake! I didn't notice it until the first hole was drilled and I lost about a 0.032" of vertical accuracy. But because the spinner is curved and the 2X4 is not, the 2X4 was away from the spinner at the drill point by about 3/16". The lesson I learned here is that unless you're are lucky, the spinner may not lie flush to the bulkhead flange at the point you will need to attach nutplates. It may lie flush at the top of the flange or at the bottom of the flange. There's probably more than one way to do this, but if your 2X4, which was clamped into position flush with the flange, now touches the spinner below the drill point, the spinner will be making the best contact with the flange at/near the top - mark for drilling your nutplates as close to the top as possible. If it touches the spinner above the drill point, mark for drilling your nutplates as close to the bottom as possible after taking into account appropriate edge distances. I drilled the aft bulkhead after the front bulkhead was drilled and clecoed. Start by marking the edge of the blade cutouts on the flange. Take the spinner off and mark the first four holes 5/8" from the blade cutout as Van's specifies. Divide up each half into 6 equal segments to yield 7 screws per side, and then drill with a #40 bit without the spinner in place. Now, cleco the spinner onto the front bulkhead and back drill and cleco the main bulkhead starting in the center of each side and working toward the blade cutouts. |
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Progress
- Forward Spinner Bulkhead Spacer, 2/15/05. Once I
got my initial prop blade cutouts in the spinner so that it could seat on
the aft main bulkhead, I was bummed out at the amount of play between the
spinner and the front bulkhead - about 3/16". I wasn't really
keen on Van's 'fiberglass buildup method' because for one I wasn't
using their glass spinner, and more importantly, I thought getting a
really even layer around was iffy, weight variable, and generally a
mess. I am not looking forward to the fiberglass work. I found
that by putting washers between the front bulkhead and the prop dome, I
could get a good fit on both the fore and aft bulkheads. But the
thought of four washers on that high vibration/stress area was unsettling.
In the past I've tried to look up technique in Tony Bingelis' books, and I am sad to say, when I need specific information in the past, it wasn't to be found in his books. So, I've kind of fallen out of the habit of using his books for reference. After leaving a message on my A&P buddy's phone, I dug out Tony. In this case, he has a nice chapter wholly on new spinner installations. Cool. Spacers, my interpretation shown, is the way to go. Grousing Van's Support: (Love the plane, not wild about support.) There are no torque specs for the 4 bolts that hold the front spinner bulkhead in place on the front dome of the Hartzell prop. The dome is aluminum. This email to Hartzell:
got this reply:
A follow-up to Van's:
garnered this response:
It's Van's design. I don't know if they knew Hartzell did not design those four tapped holes in the hub dome for a front spinner bulkhead adaptation, but Van's does have engineers and someone there designed that spinner bulkhead, but "tech support" apparently could not take the time to ask their engineers. Thanks. You're on your own. We designed it, but all we can give you in terms of 'support' is "cautions about using bolts that are too long." Like I said, great plane, but support that makes you feel like these folks are so aloof because of it that they have the belief that no matter how flip their support is, their company is immune. Steve Wittman, God rest his soul, and his wife lost their lives, as far as I know, because Steve used an incompatible glue on the fabric-covered ailerons of his last Tailwind. Steve knew more about airplanes than I ever will. Toney Bingelis says in his book on engines: "In short, I am convinced now that anyone who installs a spinner without a proper fitting front bulkhead is begging for fate to take a swat at him." I think I have a right to expect professional support from Van's on their designs. Since it is clear Hartzell did not design those four holes for that purpose, I think it is reasonable to question what torque is required to make that a "proper fitting front bulkhead". From my perspective, the answer I got from Van's seems intended to be legally evasive, or just plain lazy. |
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Tip - Rear Spinner Bulkhead Stiffener, 2/14/05. If you're using a constant speed prop, you'll need to cut out the rear bulkhead stiffener to match the bulkhead and make room for the prop hub. After marking the cutout and putting down a bed of duct tape, I used a saber saw to make the initial cut. My technique for getting a nice match between the two pieces is to simply clamp them in a vice, mark the already cut edge with a felt pen. I used red. Then use a rotary file in your Dremel tool to grind carefully just until the felt pen marking gets "rubbed" away. Finish up with some 600 grit wet-dry abrasive and you're good-to-go! |
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Tip - Tip-Up Canopy Frame Stiffener Shims, 2/13/05. When you fit and drill your canopy frame stiffeners in place, you will introduce three more holes. One of the four outside rivets can be drilled to use one of the holes already shimmed. The thick-to-thin single piece of formed aluminum started life as a piece of 0.125" stock. |
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Mistake - Shims for Forward Canopy Skin, 2/12/05. I had to make shims for the front canopy skin, which you can better visualize in the "Tip" for 2/13/05. I chose to make these by measuring the gap between the skin and the underlying structure and then adding layers of 0.032" aluminum for each hole. I figured this would be the easiest way to manage/place the skims for final assembly and riveting. Once the skims were made I clecoed them to the top skin (the only thing with holes in at the time), and then scotch taped the shims to the skin so I could remove the clecos and cleco the skin to the frame everywhere else. Finally I could drill and cleco through the frame under the shims. Here's the mistake: I didn't notice that most aft hole to be drilled was very close to a rather sharp bend in the underlying frame. When I removed the skin after drilling and clecoing everything with the shims in place, I noticed that the skin had a noticeable 'dimple' in it where I "forced" it to form around the shim that was protruding past the edge of the bend in the frame. What's shown in the picture is my "fix" - I cut, formed, and filed the aft-lower edge of the shim so that the skin would lie better over the curve there. |
