You just know this has to be good because I am posting again so soon! Today I sat in my airplane and made airplane noises!!! Then my wife climbed in, too.
What this means is that I now have seats in the airplane. Well, a seat actually. I decided to go with a bench seat arrangement. I built some supports to go under the seat and used 3 mm plywood for the seat bottom, then used some 6 mm plywood for the seat back. I will need to get some foam padding and some reasonable upholstery as well.
I also drilled some holes and mounted the rudder pedals, but either I will need to put some serious padding on the seat back, or I will need to move the pedals back about four inches. I really don’t think that my legs will grow any longer, so waiting until I get taller is probably out.
Now for the pictures:
This is how I started the seat. I made four frames to support the seat bottom at the same height as the bottom of the opening in the rear bulkhead. These were 21 inches long. I glued them up and then glued them to a piece of plywood going across the front of the seat bottom. The seat bottom itself is 24 inches wide by the inside width of the fuselage. The seat is notched so that it will fit over the bottom of the rear bulkhead.
There is the seat bottom in place.
And then the seat back in in position.
Here are the rudder pedals.
As long as things were going along quite nicely I decided to drill the holes to mount the fin. However, the fin is too tall to allow me to put the tailwheel on my workbench in the garage, so I can’t get the plane in the garage with the fin in place.
And here is proof that the seat works and is able to support me.
Yes, things are progressing again. The tailwheel is now in place, but that does not mean that it is fastened to the fuselage permanently. I am only using temporary bolts for two purposes; first, I needed to find out exactly how long the permanent bolts need to be, and second, the bolt holes need to be sealed on the inside. I have been thinking that I will probably use drilled bolts and castellated nuts and cotter pins to fasten the tailwheel permanently.
I did take some pictures. Last Saturday when the work was being done, the weather was cool and a bit wet. However, it was nice enough that I could get the plane outside and take a few pictures. Then Marsha offered to take a picture of me with the airplane so that you could get an idea of the size of the project. So here are the pictures.
It has been more than a month since my last post, but work has commenced and Sawdust is now on its wheels! We are currently in Minnesota for a quick visit and I brought the engine mount with to show my brother-in-law that I really can melt steel tubes together. Once he is done laughing I am going to see if he would be willing to show me how it is supposed to be done, or loan me the use of his torch for a while.
The last post showed the landing gear parts. Jeremiah and I spent an evening putting them in place and attaching the wheels and breaks. I expected to need to shorten the shock struts, but when we put them in place we found that I will probably need to extend them a bit. The wheels are sort of tucked under as they sit now. I am hoping that they will spread out a bit when the full weight of the fuselage, wings and engine are in place, but I suspect that I will still have to add a bit of length to each of them.
The wheels and breaks went on fairly easily. I have a 1/4″ thick plate to serve as an axle mount for each wheel. The axles were purchased from Matco and things line up pretty well. I may need to make a few adjustments before the final assembly. The main thing that I found was that the break calipers will need to be on the leading side of the wheels. Most of the installations that I have seen have had the calipers on the rear side of the wheel assembly. I don’t know if it really makes any difference as far as performance goes, but by positioning the calipers on the front side of the wheel assemblies I will be able to perform wheel and break maintenance much easier.
When we finished installing the wheels my wife noticed that the top of the fuselage was taller than the opening of the garage door. This is not a major problem because I will have to take things apart at least a couple more times before the plane is done, but it would be nice to be able to move it out onto the driveway to do some of the other work fitting things together. However, moving the fuselage forward allowed the tail to drop down and this reduced the overall height of the plane so that it does fit through the garage door.
I did take a few pictures of things as they are now, so here they are:
Here is the way the plane sits in the garage. This position leaves plenty of room ahead of the firewall for the lawnmowers or snow blower. In this attitude it is too tall to get through the garage door.
Another view of the same thing. This gives a little better view of the engine mount.
This is a detailed view of how the shock struts fit and hold the landing gear in place.
Here you can see how the wheels sort of tuck under just a bit. This also gives a bit of an idea of the overall size of the plane.
This is from the other side. Here you can see the pilot door opening and the seat mock up (cardboard). One of my next projects is to build the seats. Once they are done and in place I should be able to position the rudder pedals. I will place the rudder pedals at the best location for me since this is my airplane.
Speaking of the rudder pedals, they are ready to be installed. Except that they are too long for my feet. I will need to cut them off a couple of inches and add the mounts for the break main cylinders and the toe breaks.
The main landing gear has been fit into place, but there are a couple of things that I still want to do with them. The plans call for a 0.040″ thick strip of steel to be welded on the inside of the V tubes. Then an aluminum sheet is bent to become a step and is bolted to the steel strips. I don’t really like that arrangement, so I am thinking about adding a tube across the top of each V and welding on a peg to act as a step. My tires are large enough to provide a pretty good first step up, so another small peg type step should be almost ideal. The peg step is what Cal and Fred did with their Pobers and I kind of like how they look. This arrangement will allow the landing gear legs to be covered and painted to match the fuselage.
So here is what things look like at present. I expect to order the tailwheel early next week, so the next post should have pictures of the tailwheel and vertical stabilizer installations.
I have also been working just a little bit on the horizontal stabilizer, but that has been a very slow process and will be covered in a later post.
Greetings on the Ides of March! I hope everyone had a great Pi day yesterday. Someone did bring in pie for us at work yesterday and I managed to resist until the last part of the day.
So, on to an update on the progress on Sawdust.
The shock struts are now complete. Therefore, pictures are in order, and here they are:
The shock strut at the top shows all the parts. Then just below it is the fully assembled shock strut. At this point they are interchangeable from one side to the other. The springs were given to me by Cal with the caviot that I could not give them back to him. They were originally for his Pober Jr Ace, but they turned out to be just a bit too springy for him. They are pretty stiff and I think they will be good for Sawdust.
At the right side of the picture is the cross brace that goes on the bottom of the fuselage. This piece provides a place for the shock struts to fasten to.
Toward the bottom of the picture is the front leg of the landing gear and below that is one of the axles.
This is a closer view of the disassembled shock strut. The spring goes over the outside tube (short one), then the long tube goes through the short tube and the collar fits over the short tube and a bolt goes through all of them. The short tube has a three inch slot in it to allow the bolt to slide. The result is that the spring is compressed when there is tension on the shock strut. It is sort of hard to explain, but it works very nicely.
Here is a close up of how the axle will fit to the landing gear leg. You can see the welding that I did myself! I know it is not real pretty, but I am sure it will hold. The plate on the end of the leg was tacked in place by me, then Fred used his TIG welder to do the final weld. The plate is 0.25″ thick and the tube that it is welded to is 1.25″ diameter with a .125″ wall thickness, so these parts are pretty hefty.
The axle is bolted to the plate on the landing gear leg using four AN4 bolts. AN4 translates into 1/4″ diameter.
The wheels and tires came a while back, but are still waiting for the landing gear to be finished. The hubs are 6″ diameter and the tires are 6.00 x 8 which works out to an overall diameter of about 22″. The tires say not to inflate to more than 20 psi. That makes them fairly soft compared to car tires, but that should add a bit of cussion for rough landings.
This is the back side of the wheel assembly. You can see the disk caliper and rotor facing up. There are a couple of zip ties holding things together. That is the way they came from Matco. I cut the ties on the other wheel to get the axle out so I could mark the holes.
I need to finish welding up the landing gear, then move on to the rudder pedals, the control stick and engine mount. Material for the controls and engine mount is suppose to arrive today.
Progress has been focusing on the landing gear this winter. I need to get more pictures for in here and maybe I will be able to do that this next week. However, I did remember to take a few of the current project which is the shock struts.
Cal has been gracious enough to allow me to use his gas welder setup to learn to weld, and Fred has kindly shown me the basics. Then they turned me loose and let me burn metal! I still burn holes in my tubing, but my welding is going better each time I work on a new part.
So far the front legs of the main landing gear are done. I did the gas welding which was the majority of the work, then Fred took them to TIG weld the axle mounting plates to the lower gear tube. Both of these parts are fairly heavy, so he thought it would have better penetration using the TIG than using the gas welder.
The way this has worked is that during the week I have been cutting and fitting metal and building jigs to hold the parts while I welded them. Then on either Saturday or Sunday afternoon I would go to Cal’s place and do the actual welding. This has worked quite nicely.
This week I have been making the parts for the shock struts. At lunch today I cut the last few parts and took some pictures.
So, here are all the pieces that go into the shock struts except the springs and a few bolts. I am waiting for my checking account to recover a bit before I order the springs, but that should happen next week. I have the bolts, washers and nuts that I will use.
Even though these parts seem to be pointing down, they are the parts for the top section of the shock strut.
I guess what you need to understand is that the shock strut is sort of like a shock absorber. It is basically three parts, an upper tube, a lower tube that slides inside the upper tube, and a spring. There will be a big washer welded to the lower end of the upper tube. The spring will slide over the top of the upper tube and sits against the washer. Then a collar with another big washer slides over the upper tube and sits against the top of the spring. The lower tube extends through the inside of the upper tube far enough beyond the end of the spring that a hole can be drilled through the collar and lower tube to allow a bolt to secure them together. If this is all that happens then we would just have a solid assembly and that would not give us any suspension at all. Therefore, slots will need to be cut in the upper tube to allow the bolt to slide. I will try to remember to add pictures as this all goes together.
The next issue that I had to deal with was that there is a slight discrepancy between some of my sub assemblies. The assembly where the upper end of the shock strut fastens was built according to the plans. The shock struts are being built from the plans in an article by Tony Bingelis in one of his books that I have. The upper tube is 7/8″ in diameter. However, the assembly where it will be fastened will accommodate nothing larger than 3/4″. Therefore, I had to find a way to make the reduction.
This is why I have a 4″ piece of 3/4″ tube inserted into the top end of the 7/8″ tube. To provide the most possible welded area between the two tubes, I cut a “fishmouth” in the top end of each of the 7/8″ tubes, then I drilled a 5/16″ hole through the larger tube at the bottom of the fishmouth. The plan is to weld all along the edge of the fishmouths and in the inside of the hole. I think that should secure things pretty well. These techniques are used when repairs are required on a steel tube fuselage, so they should be acceptable.
Here are the parts that will make up the spring retainers. At the bottom of each upper tube I will weld one of the big washers. However, the washers have a hole diameter of just over 1″ and the upper tube is 7/8″ outside diameter. Therefore I cut a couple of short pieces of the 1″ tube to put inside the washer holes and over the tube. The plan is to weld them all together securely.
The upper collar consists of a 2″ piece of 1″ tube with a washer welded to it. The washer sits against the top of the spring and a hole is drilled through the tube to allow an AN-5 bolt (5/16″ diameter) to go through.
At this time I do not have the springs. I will need to wait a week or so before my checkbook is able to handle the purchase. The springs that I will use cost about $50.00 each. However, Fred has the same setup on his plane and it is currently out at Cal’s. So when I go to do my welding I can find out exactly where the washers need to be welded on the tubes and where the holes have to be drilled.
Well, it is the new year and I really don’t have much progress to report. The fuselage is done and ready for landing gear and controls. The limited time that I have to work on the plane are focusing on the landing gear and on the horizontal tail surfaces. The landing gear parts are being cut and prepared for welding in the garage on nice days. The horizontal tail surfaces are being worked on in the basement when the garage is too cold and time allows.
Unfortunately, my wife broke her leg just before Thanksgiving, so I have been doing more of the housework and helping her to behave herself so that she heals faster.
Thanksgiving was nice. I learned to roast a turkey in the oven. I also made a pumpkin pie. I got the recipe from www.cookingforengineers.com. That is a great site to get simple to follow recipes and cooking instructions. It tends to be geared toward guys.
For Christmas our oldest son and his girlfriend invited us to join them at the southern end of the Baja. They were borrowing a house from a friend of theirs just south of Los Barriles which is on the Sea of Cortez side of the Baja. We were a bit concerned about my wife’s leg, but it really worked to our advantage. We were met at the bottom of the airplane stairs with a wheel chair and were taken around everyone else and were through customs in about two minutes. Well, maybe five minutes, but we were the first ones through. If you need to go through customs break a leg.
Well, it is time to get back to work. Hopefully some of it will be on the plane.
Last night I glued the last piece to the fuselage. This morning I pulled the staples and sanded the last areas that needed sanding. So, I thought I would take a few closeup pictures of things and post them here.
This is the last piece. That wedge shaped chunk of oak on the top of the fuselage. Actually the fuselage is upside down, so it is really on the bottom of the fuselage, but it just doesn’t look like it.
The tailwheel leaf spring will attach to the plane sort of like this. I still need to drill a few holes and figure out exactly what bolts I will need to order to hold things together. Chris (the airplane designer) has some ideas in the plans, but my particular plane may be off just a bit due to slight differences in materials and measuring. The hole in the spring is probably not quite the same size as the plans call for. The spring is for an Aeronca 7AC or 7EC. My first solo was in a 7EC, but that was a long time ago.
Here is the side as it now sits. The side and bottom stringers are in place and seem to fit quite nicely. I decided to anchor the forward end of the side stringers at the bottom of the outside plywood skin that forms the side window frame. The aft end of the stringer ends half way up the plywood side at the tail. This worked out pretty well.
This is a closup view of the area of the cabin bottom that Jeremiah sealed last Saturday. We need to add another coat of sealer before we install the landing gear brackets.
The front landing gear bracket is positioned just forward of the front bulkhead. The fuselage nose side plywood bends at just that point. Therefore, a piece of something needs to be positioned and shaped to give support to the bracket. I found that a piece of 3mm plywood was just right for this.
Now we can concentrate on sealing the fuselage. We need to finish the first coat with the fuselage in this position, then turn it right side up and apply a couple of coats that way. Then it gets turned upside down again for the second bottom coat and the installation of the landing gear brackets.
So, what have we been up to with Sawdust? At this point there is one piece of wood left to glue to the fuselage.
Last weekend Jeremiah wanted to help me with the airplane by doing something other than simply handing me tools or holding materials or helping me cut materials. So, I was at the point where we could start applying sanding sealer. He sort of likes to do that, so I turned him loose on sealing the fuselage starting with the cabin bottom.
So here we are. This is the picture that he didn’t want posted on-line because he didn’t think his expression was very good. Anyway, he is busy brushing on the sealer and he is doing a pretty good job of it.
As you can see the bottom of the cabin has the floor supports which are sort of like floor joists in a house. The plywood for the cabin floor is only 3mm thick which is about 1/8 of an inch. Jeremiah was concerned that plywood that thin would not be able to support us if we should stand up while in flight. Well, the cabin is not big enough to stand up in, so I am not worried about it.
The plane is still upside down. The last piece to be glued to the fuselage is a wedge shaped piece of oak that will be a support for the tailwheel spring. This is located at the far aft end of the fuselage on the bottom. It is 3/4 inch thick at the rear and about 1/16″ thick at the front. It is about 6 inches wide at the front and about 2 1/2 inches wide at the back. Once it is glued in place I will mark and drill some holes in it.
I will try to take more pictures this weekend and do another post next week.
Things have been quite busy this summer. The fuselage is nearing completion! At this time I have only about half a dozen wood pieces to glue to the fuselage and it will be ready for sealing.
Let’s see … the last time I posted was on June 20th, so there are a lot of pictures to show.
That worked quite nicely. Ben has been busy fixing WordPress and loading the picture went very quickly! I am impressed!
Anyway, as you can see the fuselage cross members have been glued in place as well as the roof. The tail fin is just clamped in place in this picture. I just wanted to see what it would look like.
This shows how I joined the fuselage top stringer to the center roof support. There will be stringers like this one on the bottom and on each side. Without the stringers the fuselage would look VERY square. The stringers push the fabric out from the “surface” of the fuselage sides just enough to give it a bit of a rounded look. They also add just a little extra support for all the spacers and diagonals.
Here is a better view of the top of the fuselage. This is from near the tail looking toward the front.
This shows the way that the firewall will fit with things. You can almost start seeing it start to look like an airplane.
Once the nose sides were glued in place things started to really look like an airplane!
Before the firewall could be fitted in place and the nose sides glued to it, it had to be filled with fiberglass and the front sheet of plywood needed to be glued to it. The fiberglass is for noise absorbsion according to the plans. I intend to wear a good headset, so that may be as secondary issue. But anything that can make the cabin a bit quieter is worth the effort.
OOPS! Well, I guess this is the first spot of “hanger rash” for my plane. One of the pipe clamps that I had leaning on the frame started sliding and the handle bumped the inside of the 1.5mm plywood. Fortunately, there will be a plywood window retainer glued to the inside of this area, so this boo-boo will get fixed. In fact, I installed that piece this afternoon and I think things will be just fine when the glue dries.
Here are the floor supports. They are sort of like the floor joists in a house except that you don’t stand on them. The main purpose is to support the seat(s). I am not sure if I will build bucket seats or a bench seat. I have qute a bit of time to think about that yet.
I have had a number of people ask how I make my scarf joints. This shows how they start. To begin this section I should probably explain what a scarf joint is. A scarf joint is a joint where the two pieces of material (in my case wood or plywood, and in this example plywood) are tapered then glued together on the taper. This provides a very wide glue joint and the resulting joint is just as strong as (sometimes stronger than) the material being joined.
This is a picture of two sheets of 3mm plywood that will make the floor of the plane’s cabin. The top sheet was set back from the edge of the bottom sheet by 1 1/2″ then clamped in place. I used my hand held belt sander to sand the taper across both pieces of plywood at the same time. Plywood is made up of several layers of wood that area glued together. The glue shows up as the dark lines in the picture. Since all the layers are the same thickness, the glue lines should end up being evenly spaced and parallel to each other. I didn’t get everything perfect, but it is close enough for what I am doing.
The joint will be “clamped” against a piece of plywood. I have a 3/4″ thick piece of plywood that I use for lots of things and it works very nicely for this application as well. First I cover the 3/4″ plywood with wax paper so that it won’t become part of the floor. Then I place one of the pieces of floor plywood that I just got done sanding on the wax paper. Next I smear glue all over the area that I sanded and fit the sanded area of the other piece of plywood into the glue. Then I grab my staple gun and put a staple near one end of the joint to hold that end in place and I proceed to run a series of staples along the joint. The staples are my “micro-clamps” and they work very well.
This shows the way that the joint ends up. Notice that I put in two rows of staples to ensure proper contact between the pieces of plywood. When the glue cured I pull all the staples and sand the joint to remove the excess glue.
The finished scarf joint. The floor has been glued into place and the scarf joint will be under the seat(s). The joint is not invisible, but it doesn’t look too bad.
The floor is in place.
The instrument pannel is in place.
Snice these pictures were taken the brackets to hold the landing gear to the fuselage have been completed. Once the last pieces have been glued to the fuselage, we will be able to apply sanding sealer. Then it will be on to the landing gear!
Almost a month since my last post, but thing have progressed nicely. I now have a fuselage! So, let me fill you in on what has been happening.
The last time I was discussing the windshield frame, so here it is all set in its jig, ready to be welded. I ended up cutting the lower back corners off of the jig in order to get it to fit under the bed cover for my pickup. Then it was off to Minnesota to see my brother in law, Don, and get this welded.
I am not a welder. I have played with welding just a little bit, but Don is a professional welder and a welding teacher. It took him less than two hours to do all the welding for this piece.
Here is how the finished product will fit in the plane. The sides are only clamped to the bulkhead to hold things in place. The firewall has not bee built yet, so I have a couple of pieces of plywood holding the front end of the windshield frame in place to give a better idea of how it will fit.
This is a little different angle on the same subject showing more of the side of the fuselage and the windshield frame. Don sure did a nice job!
One of the things that I didn’t think about was that welding leaves a bead along the welded joint. This is good from a strength standpoint, but it means that I had to rasp away a bit of wood to allow the metal bracket to fit to the fuselage side tightly. Not a problem. I just got out my trusty rasp and gently removed what was required. Then I applied two coats of wood sealer.
I found some wood sealer that advertised “water clean up”. Well, it was worth a try. I was very plesantly surprised by this product. I think the brand is Valvethane or something like that. Anyway, I bought it quite a while ago and it had not settled. A quick stir with a stick and I applied the first coat. The color is sort of milky, but there is very little if any odor. The brush rinsed out quickly with warm water. I applied this in the morning and by lunch time it was dry. A quick sanding and things were ready for the second coat.
I expected the brush to be somewhat stiff like I often find brushes that have been used to apply latex paint. The brush was soft like it was brand new! The second coat went on smoothly and quickly and the brush cleaned up quickly and thoroughly. The second coat was dry in about an hour and the brush was still like new. I am very sold on this product.
I put some more finishing touches on the fuselage sides before assembly. I wanted to be sure that the side windows were identical, so I clamped the sides together with the outsides facing each other. Then I drew lines 1 1/2″ in from the frame pieces all around. I think rounded corners look nicer and more finished than sharp corners, so I took a spray paint can and used it as my template for the corner radiuses. When I had everything marked I tried out the scrollsaw attachement to my Dremel tool and used it to cut the hole. It worked very well. A bit of sanding and the holes were finished.
The next step was to mark the locations for the bulkheads on each side. Now I didn’t get pictures of this portion of construction, but you can see the result above. I actually assembled the fuselage upside down. The main bulkhead needed to be flush with the bottom of the fuselage sides and a gusset was applied to hold them together. Ensuring the proper fit worked best with the fuselage upside down.
Since things were bottom up, I installed the bottom cross pieces which stiffened the whole assembly. When that was done I turned the fuselage right side up and am now working on the top portion.
The fuselage looks quite large and it will seat two people, but the way it is constructed makes it quite light. I am able to lift it on and off of the worktable by myself. However, it won’t be too long before I will need to take the table apart so I can have more room to work on it lower down. At this point I put it on the floor when I am working on it and I put it on the table when my wife’s car needs to be put in the garage.
The thing that I am mulling over at present is whether the upper cross pieces should be fitted between the upper longerons, or if they should be positioned on the fuselage side above the longerons. Right now I am thinking that on the longerons would provide the most strength, but I will wait and see what some of the other builders say about it.
Of course, one of the most important pieces is the tailpost. This is where the fin will fasten to the fuselage. The large hole is to allow clearance around the nut for the bolt that fastens the hinge to the fin. The hinge connects the rudder to the fin. So, for this time, this is the end.
