Making a Rotisserie for the Fuselage - Part 1

 While I continue to review my parts situation for the wings to prepare to place a new order with Vans and other vendors, I caught an ad from Harbor Freight a couple of weeks ago for a 1,000 pound capacity Engine Stand that many builders have used as a rotating rotisserie for the RV-8 fuselage. The rotisserie is mainly used as a back-saving tool while assembling many of the parts and components of the cockpit interior and floor panels. It may also come in very handy if I decide to paint my own airplane, which I am once again heavily considering. I have a new idea for a paint job for this airplane that so far seems to be pretty unique. That's all that I am willing to share about that for now, in the interest of keeping it as unique as possible. :)

 I have reviewed numerous other build logs from other builders, but I still rely most heavily on the log from Steve Riffe, who has been flying his airplane now for about 3.5 years or so. He used the same engine stand for his fuselage, and he also learned about this from other builders. While looking at pics of his engine stand, I noticed that the frame design is different, because I think they change designs every so often for the same product. Changes are mainly with how the wheels are attached to the base, and how the support bracket that attaches to the vertical bar and the horizontal bar to add support to that critical area is constructed. I purchased the stand brand new from HF for under $70.00. It requires minor assembly, but the parts are heavy, so be prepared.

Since the QB fuse as delivered by VANs only weights between 150-200 pounds max (if that), this 1,000 lb. stand is more than sufficient for the job. the main issue is the length of the fuse, which creates a long moment (Remember your weight and balance training - WxA=M). This means that if the tail is unsupported while the front is suspended by the engine stand, all of that weight along the entire length of the fuselage has to be supported by the stand and its attach points to the firewall. The idea is to use the stand in the front, and lay the tail down on a small saw horse, milk carton, or custom-built wood stand as needed, so the weight that must be supported by the stand itself is minimized as much as possible. I also wanted this particular stand instead of other available models because it has the additional lateral wheel bracket in the front, which helps provide some additional lateral stability to the fuselage when mounted on the stand. 

The main problem I encountered when considering this, is a lack of  a detailed information about the hardware used. So I will attempt to solve that problem. As always, keep in mind that I make no claim of suitability or guarantee that your results will match mine, so you are responsible for determining if thi will work for you or not. YMMV. 

Here is a pic of the assembled HF Engine stand, ready to be converted to a fuselage stand:

I used my yellow angle finder tool to determine the angle of the vertical post and the base support leg, since the angle is not 90 degrees. Most folks remove the front wheels of the stand to bring the vertical post closer to 90 degrees, so that it aligns vertically with the firewall when mounted to the stand. This needs to be done so that it does not put any undo stress on the firewall when mounted to the stand, which would be very bad. 

Since the wheel brackets on mine seem to be a little higher than others, I may need to compensate for that a little by raising the front up a little more with wood shims, but time will tell on that. The angle I measured is almost exactly 5 degrees, although in the above pic it  appears to be much greater than that. 

The rotating bracket that comes with the stand that the firewall will be mounted to comes with 4 "spider leg" attachments that are normally used for running heavy bolts through the spacers or lugs at one end of each arm that then screw into the back of a car engine. 2 of the arms are shown in the pic below.

The mounting plate has slotted holes to allow the location of the spiders to be positioned so that they match the mounting holes on the engine. Unfortunately we have to change this up a bit to modify this assembly for use with the fuselage, but it is not too difficult to do. I will still use the spider arms, but they will be attached to the ends of some angle iron that is cut to the correct length to act as an extension, so that the mounting plate remains near the center of the firewall, while the spiders will be bolted to the 4 holes in each corner of the engine mount holes and brackets behind the firewall, AND to the angle iron extensions. 

Similar to Steve, I decided to use AN hardware for most of the attach points for the spiders to the firewall/engine mount brackets, which have a minimum 125,000 lbs. of tensile strength, to ensure that the bracket has enough strength to stay attached to the firewall the entire time. The immediate problem that has to be overcome is that the stand comes with very large metric bolts. 

Unfortunately, when Vans builds the QB fuselage, all the engine mount holes are only pre-drilled to 3/16ths of  an inch, which is the smallest AN bolt diameter you can obtain before having to revert to screws. Furthermore, if you read ahead in the VAF forums and the Vans instructions for the Fuselage assembly, you will find that they say NOT to drill out those engine mount holes until you have the actual engine mount in your possession, so you can use it as a drill guide. 

This is necessary because the weldments for every engine mount vary a bit from one to the other, so you are not supposed to up-size the bolt holes without the engine mount to ensure the holes are drilled out correctly. The engine mount bolts are 3/8 inches thick, or AN-6 I  think, so they are substantially larger than 3/16 inches. Since I do not have my engine mount yet, I did not want to upsize the holes, but I was also concerned that this would mean that only AN3 sized-hardware would be attached to each existing hole. 

Steve informed me that he did exactly that - used the AN3 bolts in each corner, and he had no issues with anything while using the rotisserie. I also contacted Vans about this, and they said it would probably be OK to upsize the holes about half way in between the current size and the final size, since most engine mount holes may only vary by a max of 1/8 of an inch or less from each other. They also thought that AN 3 bolts would be "a little light. 

Other builders decided to drill up to AN 4 bolt holes, and I think I saw others yet again that drilled them out the final AN 6 size. At the end of the day, I decided to stay with the AN3 bolts to avoid upsizing the bolt holes without the engine mount. Steve said he had no issues, and the reality is that all the other bolts used in the assembly are the same beefy ones provided with the engine mount. So I think his will be fine.

With that decided, there is another  problem that I felt I needed to solve. While the AN 3 bolts will precisely fit in the predrilled holes in the firewall, the predrilled holes in each spider leg are extremely large, I was concerned about running such a small sized bolt through the large hole in the spacer lug in the spider leg, without having some kind of additional support for the bolt shank. So, similar to another builder (I am sorry I did not capture his build log) I decided to cut a wood dowel to the correct length to fit inside the lug or extension, and insert it into the larger hole in each spider. It turns out that a 5/8 inch dowel from HD aircraft supply works very nicely here, at least as far as the fit into the spider lug is concerned. I measured and then cut the 5/8 inch dowel into 4 separate 1 1/2 inch long inserts using my bandsaw, as shown below.

After you have cut the spacers, the next step is to take a rubber mallet and tap them into "submission" into each lug hole:

IT turns out to be a very nice "press" fit. Each dowel is only long enough to reach the base of the lug where it is welded to the spider arm. The dowel will not fit all the way to the bottom of the arm because the holes from the lug that they welded to the top of the bar are not the same size. The holes in the bar are a little smaller, so they will stop at that point.

Now for the hard part. The next step was to drill out  a 3/16 inch hole in the center of each dowel.  I won't lie, for me this turned out to be a bit of a nightmare, because I found out that dowels do not like to allow a drill bit to follow a straight path from one end to the other. All of initial holes I drilled ended up being misaligned, and I ended up having to continue "custom" drilling each hole in the dowels to "force" them to run more or less from center to center. Basically that means I had to enlarge the hole a bit by using a drill bit to gouge out the holes. 

I also needed to create a few replacement dowels, because the hole drilling went so badly that I could not salvage the insert. I tried using my massive large drill press first. It vibrates badly, and I cannot figure out how to secure things very well to the stupid drill table. After a few attempts with the drill press, I gave up and decided to try it free hand.

First I tried to put it in my table vise vertically - same result. the drill bit would meet the wood and instantly take its own undesirable path to the other end of the dowel.

 Then I tried putting them flat on a drill board and clamping then down with bar clamps:

I originally started with a #40 drill bit, then followed with a #30, followed by a 3/16th inch drill bit for final drilling. This also did not work very well for me. The hole on one end starts out centered, and the hole in the opposite end is completely uncentered and off to one side. I even used my center punch to try to start the hole in the exact center of each dowel, and this did not help much either.

Here are the results of several attempts. This side looks OK:

But not this side:

Example of extra gouging:

About as badly aligned as it can get:

At the end of it all I decided to put my 3/16 inch drill bit into my cordless drill, and after drilling the initial hole, I manually "corrected" any offset in each hole by gouging it out with the drill as best I could.  Then I ran each bolt through the holes to check for centering. it does not need to be absolutely perfect, but I wanted it as close as possible to avoid and excess stress on any of the bolts, or the points where they are attached.  Here are the end results:

Here is an example, taken before I made and drilled the dowel inserts, of the upper left corner of the firewall/engine mount hole, and how the spiders are attached to it. The lower end will be attached to the angle iron:

And here is pic that l also do not see in anyone's build log - how the bolt attachment appears on the inside of the engine mount hole, taken from the rear of the firewall, where the bolt protrudes through the predrilled hole from the factory:

More on the remaining assembly in the next post..

Fixing My RIGID 14 inch Bandsaw

 these pics are year a year and half old, but the pics of the mods I performed may still help somebody else along the way, especially if  the quality of any substantial products starts to go way down due to COVID impacts, as I have already witnessed many times. The simple fact is that even for those companies that are still in operation, many of them are working with reduced staff or have experienced reductions in their labor force, and so the number and quality of those products may suffer as  result. Unfortunately, The RIGID 14 inch band saw suffered from many quality problems long before COVID. Thankfully there were some things you could do to help solve many of the problems and make it a almost first-rate tool.

First was replacing the stock black rubber  tires, which required removing both wheels from the saw. You have to completely disassemble the table, guides, and saw blade, but it wasn't too difficult to do: I found and ordered some orange colored neoprene replacement tires. removing the old tires was easy because they were horribly cracked and deteriorated. These needed to go away because they are hard rubber that develops uneven ridges over time, and this contributes to the vibration of the saw. The new tires are softer so they absorb vibration better, and the blade also tracks better. The hard part was getting them on  each wheel. When done, they looked like this:

In the last pic you can see that the width is slightly less than the entire width of the track. This was the result of my over-aggressive sanding of the edges of the tires. This was necessary because the width of the metal track of each wheel is about 7/8 inches, but the tires only come in a 1 inch width. I spent quite a bit of time reading others posts about this. Some tried fitting it "as is" but it does not sit properly in the tire track, and others tried cutting the width with a utility knife. Neither of these methods worked very well, if at all. 

Finally somebody came up with a way to fairly accurately reduce the width of the tires by sanding them down. However, this method still required some careful preparation. Basically you had to fashion a piece of wood long enough to support the tire, and with a 7/8 inch width. then you had to put the tire over the wood, clamp it down tight so that the remaining portion of the tire extended beyond the wood width, and then you carefully run it on your belt sander. Here are the pics and the number of tools involved:

the tricky part about this was not being too aggressive with the sanding and checking your progress often. The sander only reached so far, so you had to do 2/3 of it on one side and then turn it around to do the remaining portion. The idea was to keep sanding until the width of the tire was reduced to the correct depth, and stop sanding before you started to sand away the wood. The above pic does not show the tire all clamped up, which was the other difficulty. but when you hit the sander the tire is wrapped around the wood and clamped in numerous pace to keep it from moving. The hardest thing about the the clamping was being able to clamp it securely but leave enough clearance to allow the tire material to be removed by the sander without also removing material from your bar clamps. The assembly became quite heavy and unbalanced after all the clamps were applied, so this part was a bit challenging. As I stated previously, mine were a little over done, but they still seem to serve their purpose well and do not cause the saw blade or tire to move as long as proper tension is maintained on the blade.

The next big task was disassembling the saw from the stand so that a 3/4 inch piece of plywood could be fashioned that the motor and the saw would both rest on. One of the biggest causes of vibration of this saw was the hard rubber feet that the motor mounts sat on. The fix was to completely remove the rubber feet and mount the motor on the plywood. This fix also required some longer mounting bolts, and there were several vent holes in the metal stand that also had to be transferred and re-created in the plywood base. Cutting the board to size was easy. Cutting those vent slots mounting bolt slots - not so much.

Next was to reassemble the saw and motor with the new plywood stand, re-install the wheels and balance them. The wheels on this saw were notoriously unbalanced. I followed the procedures to determine the unbalanced areas, and used self sticking pinewood derby lead weights with epoxy glue to mount them to the correct locations on each wheel. 

Then came the replacement link belt from Harbor Freight, which replaces the hard rubber belt that came with the saw. This further reduces vibration because the rubber belt develops a memory as it wraps around the pullies of the motor and the bottom wheel. This causes a bump in certain locations in the belt that adds to the vibration.

The links are removeable to get the correct belt length, but it is quite the jigsaw puzzle to figure out how to do this. The other problem was not clearly understanding which way the links needed to be oriented on the pullies. After a while I found pics that clarified this. Operation of the saw confirmed that I had them positioned correctly.

The last mod was to replace the stock, metal saw blade guides with a composite product called Cool BLocks. These keep the temp of the blade down. which results in more efficient cutting and longer life of the saw blade.

And finally my math to figure out the width of the wheels and the new tires and how much I needed to remove, using a digital caliper:

And finally the packaging for the replacement tires I purchased. Once all these changes were completed I put the saw back together, did the nickel test, and the difference was like night and day. No this saw runs much more smoothly, and I can trust it with finer cuts for the airplane parts that it will be making. I also bought a rolling stand set from HF that I have not installed on it yet. Once I put my new shed together the saw will go in there, and I will be able to move it around easily on this new stand. 

This was the last thing I worked on that had anything to do with the plane over a year and half ago.

Next up, went back to HF to purchase the 1000 lb engine stand that many other RV 8 builders have used to fabricate a rotissorrie for the QB fuselage to aid in  numerous tasks with assembling parts, panting, and mounting the landing gear, etc. And yes, you have to fabricate more parts to complete this project, but it is not ear as difficult as fixing the bandsaw was. 

KPR

Restarting yet again - a year and half later

 Hard to figure out exactly where to start this Blog again. Recap - I screwed up the inner and outer skin of my left wing LE Mode in April of 2019. Tech Counselor came out and we discussed using a planishing hammer and dolly to reform the damage to the outer LE skin and inner subskin. I bought the hammer and the dolly, and was about to attempt the task of re-forming the skin, when I had yet another epiphany. 

1. I realized that positioning the dolly had to be done exactly right in a very tight spot inside the LE, and I determined that this would just be next to impossible for me.

2. After having a very honest conversation with myself, I also realized that even if I managed to reform the skins correctly, this mod went wrong almost from the start where I did not create the wood form blocks for the sub skin properly. This meant that curve of the LE of the subskin has NEVER been formed exactly as it should, and leaves a gap between the outer Le skin and the subskin that then causes issues with how the removeable plate would sit when screwed onto the subskin. It also puts additional stress on the rib flanges underneath. IOW, the removable plate will NEVER sit flush the outer skin because of the subskin deformity, and the added stress in the rib might lead to other structural problems later. I should have taken much more care and ensured that the wood form blocks I used to bend the subskin EXACTLY matched from the curvature of the LE Rib so that the radius would have mated with the LE skin correctly.

3. The final straw for me was the realization that, after seeing it all come together, there was a much easier way to approach this whole thing, without the need to use the massive subskin and all the forming, measuring, bending, cutting, laying up, and riveting that was involved. I also realized that I could still attempt this mod AFTER the plane was built per the plans that would take very little time, and could be done using much simpler techniques than my original design.

As a result of this, I decided to abandon the entire mod and order the necessary new parts, including a new left wing LE skin and some ribs to build a stock LE. The only thing I will still do differently is order a left wing LE skin from Vans WITHOUT the cutout for the stall warning vane service access plate. 

It is sad to have spent so much time and effort on this, only to reach the conclusion that I need to abandon it. It is even more sad to come to this decision only after assembling and almost completing it.  However, I am not sad about having made the attempt, as I learned tons about airplane design in the process, and I now have a very deep appreciation for those that undertake the challenge of designing airplanes from scratch. So my only regret is the time I have lost, but nothing else. Basically it was not until seeing entire mod coming together to figure out that there was a much easier, simpler, less invasive and less time-consuming way to do this. I'll keep the details of that to myself for now.

So what happened after all that?

Instead of working on the fuel tank as I previously stated in my last post, I spent the next couple of months working on some mods for my 14 inch RIGID bandsaw.  This saw became notorious for not being very well built to the point that it vibrated so badly that it was difficult to make fine, accurate cuts. With the forming of the forward Fuel tank mounting brackets looming in the distant future that would require the use of my bandsaw, I decided to spend the time to perform several well-documented mods to reduce the vibration and turn it into the tool that it should be. There are numerous You Tube videos on the subject and I watched all of them.  

I needed to purchase some new Neoprene tires for both wheels, some longer mounting bolts for the motor as well as the saw base itself, a custom cut piece of 3/4 inch plywood to fit over the top of the mounting stand, and some new composite saw guides. After much work on this, I ended up with a good saw that passes the "nickel" test, where you place a nickel on the saw table on its skinny edge, then turn the saw on. If the saw is balanced properly, the nickel will stay on its edge without falling over. I was able to achieve this to my satisfaction. 

The end result was that I could now cut the 1/4 inch thick Fuel Tank Angle Mounting brackets with reasonable accuracy on the bandsaw to reduce the amount of forming work to do after the initial cuts. One of the most challenging parts of the saw mod was the need to trim the 1 inch wide neoprene tires down to about 7/8 inches so that they fit in the wheel tracks properly. This required making a special wood frame and using my belt sander to trim the edges accordingly. That, balancing the wheels, and adding the 3/4 inch plywood base and a new composite "link" belt all contributed to solving the vibration problems with the saw. Unfortunately this was yet another delay in the build.

Then, my wife and I needed to take a much needed vacation together, so spent the next couple of months focusing on a multi-faceted trip the New York for the first time. We spent one week in New York City and did all the NYC things a newbie would want to do - Statue of Liberty/Ellis Island, 9-11 Memorial and Museum visit, which I highly recommend to any red-blooded American, went to a Broadway show, Times Square, Stood outside during a Today Show airing, had a real New York Pizza slice, learned how to ride the subway, went to Grand Central Station, Went to Battery Park, the Fashion district, visited the famous toy store FAO Schwartz, and much more.

Then we flew off to Buffalo and took a shuttle to Niagra Falls, Ontario to see the falls for the first time. We had so much fun there, and the falls were so beautiful, that we both want to go back someday. this all happened in early September of 2019. As the whole world now knows, only a few short months later all of New York and the rest of the world would be shut down and fighting for its life due to the COVID pandemic. I have not been back on the build ever since May of 2019 as the the wind just went out my sails after coming to decision about the mod, and too many other things got in the way. After  our vacation, winter and the cold set in yet again, and I still had no heat in my garage. 

Then COVID showed up in the spring of 2020, and the massive wild fires in Colorado soon followed, and it was a struggle to stay alive and to breathe through smoke and ash all at the same time. I almost lost relatives in the Troublesome Fire in Grand County - very scary. So airplane building was not on my list of things to do throughout that entire period.

I endured multiple furloughs and layoffs at work last year, only to find myself working 15 hours days, 7 days a week, for at least a couple of months. So you could say that yes, I kept my job, which was a good thing, but at great personal cost to my overall health and well-being.  Now we are in 2021, where winter is once again upon me, and still with no heat in my garage. What a wildly exhausting time it has been over the past year and a half. 

Is there a plus side to any this? Well, in the interest of counting my blessings, both kids have graduated college, have jobs, and are out of the house and successfully on their own. Several major financial burdens have ended, I have not contracted COVID nor have any of my family members, and COVID vaccinations have begun. Aside from politics and some extremely idiotic people in this world, it seems like the sun may be trying to shine on the world again. So I decided it is also time for me to re-engage with the plane project again. I need to order parts from Vans and finish the wings.

More to come..... Sorry for the long hiatus. Stay safe, respectful, and peaceful everyone. Life is too short. I'll have pics of the bandsaw mod, planishing hammer and dolly, and some other stuff in the next post.