This post is about an idea. An idea I had while on vacation at the beach in 2017. I haven’t talked about this much because it was just an idea and ideas are funny things. They are not really real, until they work. Until that moment, when something actually happens they are just a collect of thoughts, some parts, a design, and maybe some equipment. But not real. So unless you stumbled into this lost corner of my garage sometime over the last 4 years or were another racer there wasn’t really much to say.
In 2017, I had just returned to racing and while on vacation ( see vacation photo as proof I do occasionally take vacations) I decided that we needed a way to test an engine without actually putting in a car and driving on the track. We needed to test it before we got to the race. Now every racer knows you do that on a dyno. Dyno is the short name for Dynamometer – a device for measuring force, torque or power and they are crazy expensive. Even just renting time on a dyno is hundreds of dollars an hour. But I do not require all the workings of a full dyno shop just to test our small 1-2 liter motors. So I designed a test stand that could be used as a dyno.
I didn’t know anything about building a dyno, or how they work, or even how to weld. Really I knew nothing but had an idea. But that was enough. Like the Vacuum Former and the CNC projects before it, I just needed an idea and time to follow it through. I started collecting bits and parts. A pump here, a transmission there, an extra this, an extra that. To make a motor run without the car you still need all the systems of a car. The fuel system, the electrical system, the hydraulic system, the cooling system, etc. I would say it’s just as much work as building a car, it just doesn’t go anywhere. Over time (the last 4 years) it has come together.
Today we tested the pump. It worked. We successfully pumped water with a car motor. Now that doesn’t sound all that impressive. Why would you want to pump water with a car motor anyway? Well, we pump water because it is Work (physics definition of Work) and it is Work we can measure. Like MPH, RPM, or 0-60 it’s force and power. In the weeks to come the motor will run, the pump will turn, the torque will create force on the load cell and it will no longer be an idea. It will be an actual working Dyno machine.
It’s been a journey. I’ll post some of the steps and phases that lead to here. I hope that some of you have ideas that lead to things that work too. Happy workshoping.
As far as tools go the Chicago Electric Chain Saw Sharpener is not a great tool for it’s intended purpose. The motor is week, the arbor and nut are plastic, there is no shaft lock to hold the arbor still while you change disk, and so on. That said it seemed to me that it would make a good hobby chop saw for cutting really small stuff like brass rod, axles, piano wire, push rods and the like. Also the price is right at $29.99 for a good hack.
The big thing holding this saw back is the angle. As it was made to do just one job, they built in a fixed angle for sharpening. I felt that could be over come. There are some other things will need to change too. The chain advancing handle would not be needed, the blade is not right and a proper vise for holding the material to be cut. So lets look at these one by one. The handle and advancing mechanism can just be removed. We have to remove the red handle to remove the “bake handle” but it’s just a few screws.
With that out of the way we can look at the disk. They make some very thin wheels 3/64″ that have the same 7/8″ arbor. They are 4.5″ and not the 4″ that comes on it. But with a little trimming on the disk cover they will fit. They are much thinner so we will need a washer or two to make up the thickness so the arbor nut (plastic) will properly engage and tighten. Again there is no “lock” so getting a tight grip on the arbor and the arbor nut is not as easy as it should be. I don’t see an easy way to solve for this without replacing the arbor.
Next we need a good working small vice that will stand up to the parts getting hot. This simple $9 job from amazon should do.
Now to fix that angle problem. Remove the C-clip, hinge pin, and spring. Set those carefully aside for use later. Using a square to keep the 90deg angle, cut the base between 57 and 58 mm up from the bottom. Clean up the cut edges so you have the four empty holes. 3D print the replacement insert. STL print file. Use the printed part to mark a hole for a pin screw on the right back side. Use a 1/16″ drill to drill the hole. Carefully work the 3D part into the base. This is a tight fit and meant to be. We don’t want this coming out later. Put in a #4 or #6 – 1/2″ or 3/4″ screw into the hole to lock the the part in place. Re-attache the motor and disk to the base using the pin, spring, and C-clip. Refer to the image gallery bellow to follow these steps.
You should now have a good little saw for small hobby cutting. Have fun and hobby on.
The control column on the Dyno has to be all things. It’s you power, fuses, gauges, hour clock, throttle, clutch, fuel system, and note pad in one. Additionally it needs to move. Designed to be wherever you need it. Exhaust on the right side of the motor? No problem, move the controls to the left.
Like some other projects, I chose to use some CNCed Plexiglas and color from the back. I made the top hinged so you could pull two pins and easily get to the back. It has a full complement of gauges (Rev limiting Tachometer, Oil pressure, Water and Oil Temp and Air Mixture). Also the usual toggles for fuel, coil and fan. We strive for everything to be just like the racecar. Just what you need and nothing else. If we use something different on the Dyno then we do in the car then you are not going to get the same results when the motor goes in the car. We don’t want to be tuning for the bench.
The fuel tank, pump, pressure regulator, and gauge are all on one support frame. With just a few bolts they can be removed as a unit. Again I have gone for a unitized system design. Easier to fix and diagnose. The tank was a hard one to find. There aver few small metal tank options. This one is a vintage steel tank from a 70’s riding mower.
The throttle is a marine style. Since this is a standing position a foot pedal didn’t make much since. It’s another vintage find. Most new ones have gone to drive by wire and they don’t use cables anymore. I had to build up the mount from scratch to fit it in on the side of the panel. Also had to design and 3D print custom parts (grey in the photo) to make the linkage work.
The heart of the Dyno is the Pump. There are two ways to measure motor output, with load (pump or drag break) or electricity. Probably the easiest way would be to measure the wattage output and this would be done with Eddy Current brake (Telma retarder). Not being able to find one of those, I opted for the water break and load cell. If you want to know more urge you to read up at YourDyno https://yourdyno.com/brakeabsorber-dynos/
The principle is simple. Create load, measure force from load with the load cell, calculate the end result. Is it 100%? No, but really you don’t need it to be. It is a loss loss system anyway. What you need is to measure change in load over the arc of the RPM of the motor. If you want to know if your carburetor changes helped, then the measured curve of this run vs the curve of the last run is what you need to know. Did our tuning make the motor stronger or weaker? Knowing if it generated 110hp or 111hp doesn’t really help, it just a number.
Where did I get my pump? I have no idea. It was salvage someone else was getting rid of because it was all locked up. I.E Free! When I took it apart, it turned out to just be full of mud. I think it’s an old farm pump for pumping out pond or lakes. For our purposes I have mounted it on bearings. One front and one rear. This mean the pump is free to swing or pivot. We hold it in place with the load cell. That then measures the drag applied when we close down the valve on the output shaft. A 55-gallon drum provides the water, which just circulates in and out. Simple, right?
Not so much. Not know who made the pump or where it came from means no parts and you get to make your own replacement gaskets. In fact I have had work out all the details. If there is any part of this I’m not sure about, it’s the pump. If I can’t make it work I’ll have to find a truck scrap yard and a Telma retarder. But since the frame design is modular, I can just swap these parts and the rest stays the same.
I was supper thrilled when we were able to pump water. It means that the pump is good and likely to do the job we need. Happy workshoping.
Look for the other articles in the series DIY Dyno Frame and Dyno Load Cell.
The design for the Dyno’s frame is around the idea that everything is moveable and modular. Because we plan to test different engines and they come in different sizes, the parts of the dyno move along the frame to the best location for the motor being tested. Also it makes changing motors easier. For example, the radiator, fan and oil cooler unit comes off with 2 bolts. That gets those components out of the way during a motor swap. The same is true for the control panel and fuel system. We plan to test 1-2 liter BMC, Lotus/Ford and Miata motors. So, lets start there.
To calculate the frame size, I started by lining up the components in the order they needed to go and measuring everything. See photo 2. That gave me a general width that the frame needed to be. Then it was trip to the metal supply depot for several 10’ (I discovered that is the industry standard size for raw steel) lengths of 2” square steel tubing. Another stop for some heavy-duty steel casters. Once I got that home it was a kind of a “now what?” moment. I really didn’t know what to do next.
I remembered my dad had an old Craftsman stick welder out in his garage under 20 years of dust. I borrowed that. Bought a helmet, gloves and other supplies at Harbor Freight on the way home and was off to the races.
No, I wasn’t. I learned I knew absolutely nothing about welding and you just don’t pick one up and lay down nice bead weld. There are about 100 ways welding can go wrong and I must have hit 99 of them. And no, you can’t learn it from just watching some YouTube. I tried that too. In truth it’s an art that takes years to get right and after 4 years of trying I still suck. But a friend that did go to welding school came over and showed me how to start a bead and a few of the basics. On a good day, if all is in aliment, I only have to grind off half of what I weld and start over. On a good day. Welding is a skill and one I may never possess. I have accepted there are some things I’m not good at (my taxes, singing, all musical instruments) and I should just hire those out. But I did learn enough that with trial, and error, and lots of grinding that I can get non-critical metal parts to sick together. It will never pass inspection but I’m not taking it on the road.
Look for the next few articles on the Dyno Pump and Dyno Load cell. Happy workshoping.
One of the classic problems in a workshop is layout. Deciding where to put things so that you still have room for materials and work to happen but be able to use each tool at it’s station with room to maneuver. I decided to moving all the saw dust making tools to their own space. I was able to find a workshop design I liked in the SketchUp warehouse. I’ll use a simple saltbox shed design for this. SketchUP_8 Shed File
To help with the layout problem I used my trusty SketchUp again. Using just the floor and the door of the shed for reference. I modified it to the size I need. Then found most of my tools in the warehouse and moved them in so I could check the layout design and spacing. Using the layers it is a great tool for working out the details before you cut any lumber. This way you can check to see that the plywood still fits through the door and can be run on the table saw.Sketchup8 Workshop with Tools File
Many of the foam plane plans call for a formed wing. This is can be accomplished easily with a Wing Baking Jig. The Wing Jig is sized specifically to fit on the rack of a typical house oven. Just 15 mins at 200 degrees will turn the Fan-Fold foam in to a nice airfoil. Baking is an amazingly quick way to to build a wing.
Plans for the Wing Jig can be purchased from FoamFly.com here. Though I decided just to wing it on my own with out plans once I understood the design. The key piece of the design is knowing that the forming sheets are made from scraps of flashing supported by airfoil ribs. A see photos below.
Cut one a piece of 3/4″ ply 12″ x 20″.
Cut two pieces 1 1/2 ” x 20″ of 3/4″ ply.
Cut 4 or 5 slots 1/4″ wide. Cut the slots tight so the support rib fit snug.
Using the dihedral support template from the Foamie plane plans, cut 4 or 5 airfoil ribs of 1/4″ ply making sure to add the depth of the slots. Increase the airfoil shape 10% or so in sharpness. The curve needs to be a little tighter as the foam will bounce back a small amount after forming.
Cut two 20″ pieces of aluminum flashing. Crease the flashing 1 1/2″ from front edge.
Clamp the all pieces in place with C clamps and drill the front and rear clamping bolt holes.
With the ribs in place bolt down the bottom sheet of flashing. The nuts create a gap between the flashing sheets that is the space where the the foam will sit.
Insert the foam wing making sure to keep the front edge lined up and strait. If the foam is missed aligned the curve of the airfoil will be.
Using the 1 1/2″ bars clamp down the front and rear of the top flashing.
Bake for 15 minutes at 200 degrees. The wood will not burn but will be hot. Let the the foam cool in the jig.
Foam has become an inexpensive and viable building material for electric R/C plans. It’s durable, repairable and available from you local home improvement store in bulk. With the advent of Foam Safe CA super glues there is really no limit to the possible designs one can pursue.
There are literally dozens of plans available. A quick web search for Foamie Plans or Depron Foam Plans will return more than you can imagine. This will be a build of the Frog. Plans are available from FoamFly.com for $12.
I chose the Frog as my first foam build for several reasons. One It looked simple. Two: It looked like it would not take too long. Three: It is reported to be an easy flyer for park type environments.
The Plans and accompanying instructions are good. The pictures also help. Still you are building a plane from plans and not a kit. So, there is a good deal of cutting, shaping and forming to do. Learning to work with the foam can be a challenge if you have not work extensively in other materials. There is no real forgiveness when cutting the foam. It’s right or you cut out another one. The plans come with “The Definitive Guide to Working with Fan-Fold Foam”. This a 6 chapter (45 page) guide to foam building techniques. It covers tools, glues, sources, etc. If you have never built with foam before it’s well worth buying at least one of Dan Schwartz plans to get the guide. It will save you time and money hunting for the right things.
The Frog has formed wings. These are wings that hold their shape. You can see this in the photos. To get formed wings you need a wing jig. This a jig that you put the cut wings into and then place in the oven for a about 10 minutes to heat to shape. After the foam comes out of the jig it will hold the shape no other forming needed. It’s a cool trick. Being my first foam plane I had to also build a jig. I will cover that step in a second article. But here what it looks like.
The frog does build quickly. I think I spent one evening cutting out the patterns from the plans and the next night I cut the foam from the patterns.
The Tail was first and installing the hinges was the only tricky part. You have to have the right style hinges and control arms to work with foam but other than that it’s the same process as working with balsa.
Building the body on it’s side was different but easy to do. the body is tight. there is no extra room to work with. It’s width is just enough for the servo and the are to move. The servos have to go one behind the other and not side by side. The placement is not 100% spelled out. I think mine are just a little to far back. Unfortunately you don’t have the wing at this point to balance their placement with.
The motor pod is next. you really need all the parts at once to make sure it all fits. There no room to come back and add the ESC later. Once the second side of the body goes on it’s on.
Once the motor is in place it’s on to the servos. To make the line to the tail as strait as I could I mounted one right side up the other upside down. They are taped in with two sided tape. I used a small stick on one side to keep them from twisting loose from their own torque. When you feel you have got it all in place, tested and working, then glue the second side on. It seals it all in and there is no turning back. Even though the servos are only taped you would have to break the foam apart to get to one if you had to change one out.
Well, maiden flight in the back yard. Had to add weight to the nose to get it to balance out. But a few washers and it drifts along just fine. We are ready for the park.
Total time to for this build was several weeks. The wing jig took at least a week to work out. I didn’t track the cost but it wasn’t as inexpensive as one would have thought. Since the first time, I had to buy a lot of the tools to do the job. Most of the R/C gear, batteries, ESC, motor and so on can be bought on-line. However you are buying ala carte. A motor from here, receiver here, control arms and props from somewhere else. The start up cost was probably equal to buying an ARF with it all in the box. Now that said the second and third one will have all most no cost as I now have supplies for about ten plans. I would rate the difficulty as Medium to High. This is not for beginners. You have to know where you are going, know how you are going to get there and when you don’t you have to work it out on your own. There is no store to take it back to or support line to call.
Here are some stats on other Foam Plane options I considered from their Plans:
RimFire 22M-1000 Brushless
GWS IPS-A (5.86:1 Gear Ratio)
2-cell 120mAh LiPo
GWS Pico BB or Hitec HS-50
GWS Dual IPS-A (5.86:1 Gear Ratio)
2-cell 700/1200mAh Lipo
GWS Pico BB or Hitec HS-50
GWS IPS-A (5.86:1 Gear Ratio)
GWS Pico BB or Hitec HS-50
2 GWS EDP-50XC Carbon Brush
2-cell Li-ion 7.2v
280 brushed motor
8.4v 600 to 800mAh
2 micro or nano
GWS EPS-300c “2S” (2.80:1 Gear Ratio)
2-cell 1200mAh LiPo
GWS Pico or Hitec HS-50
With so many other good plane plans available to build, I’m sure I will have more to write about soon. I just need to pick my next project. Happy flying!
I have seen a lot of ads for headlight polishing products and never thought much about it. I few days ago my roommate complained that she could hardly see driving home at night. So we went to the auto store and bought some brighter headlight bulbs. We came home and changed out her headlights. It seemed to help a little but not much.
The next day I was browsing through the auto department and came across about 5 different products designed to restore your headlights. Some were complicated kits with sanding and polishing pads. I did a little research and came to the conclusion that it shouldn’t take much to do this.
I’m not recommending any one product because I have not done a side by side comparison of this product to that one. I picked a product from a brand-name who’s products I was already familiar with and it worked great. I think the key to making it work was the tools and process, not necessarily the product. I’m sure any good mild polishing compound with a wax would work.
What my research showed and what my own experience backed up is that you need a good high-speed polishing wheel and pad.
My steps where:
Wash down the lights to remove any dirt or debris.
Mask off the surrounding area with a low stick tape that won’t peal the paint or remove you wax finish.
Apply liberal amounts of compound to the light lends and pad.
Buff at a high speed.
Wash off extra compound.
Remove tape carefully.
It only took a minute or two of buffing and it was done! No muss no fuss. Really, it took longer to tape off the area than it did to do the job.
Now if you headlight lenses don’t come right back to a smooth shine, try a light sand with some wet 1500 or 2000 grit paper to knock down any deep oxidation. Be very careful if you try sanding. Use lots of water and move in light circles. Then buff again. That should do it.
Total time to do this job was about 30 mins. and the product was $7.99 from you local massive retail store. I would rate the difficulty as Low.