Terry Harper

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About Terry Harper

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  • Birthday 11/13/1963

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  1. Terry Harper

    My 1910 Mitchell "parts car" project

    Looking good Joe! The other factor in regards to engine RPM is how "horsepower" was produced and used back in the day. Comparing a big T-head or other early large displacement engine of the day with modern engines is like comparing apples and oranges. For a number of years I had an interest in the hobby of building replica WW1 aircraft - Fokkers, Sopworths etc. Since WW1 era Mercedes or Le-Rhone rotary aircraft engines are made out of un-obtainium builders had to find modern substitutes. Invariably these were modern products from the likes of Continental, Lycoming or others. The problem is the performance of a 130 hp Lycoming is nothing like that of a 110 hp. Le-Rhone rotary cranking out over 400 ft/lbs of torque at only 1,400 rpm. Yes, the Lycoming produces considerable more horsepower but the torque (approx. 262 ft/lbs) just isn’t there. Try swinging a 10 foot prop at 1,400 rpm with a modern 130 hp 0-290 Lycoming which churns out peak hp. and torque at approx. 2,600 rpm – it’s not going to happen and as many discovered, once a suitable prop was installed, that the aircraft was decidedly under powered. Same with the big T-heads. The horsepower rating may be small but the torque – which really does the work, is massive. Back in the day this suited the technology. Transmissions and clutches were not all that user friendly. The idea was to use all that torque developed at low rpm rather than constantly swapping gear ratios trying to keep the engine in the peak power band
  2. Terry Harper

    This 1912 Stoddard Dayton Saybrook chassis

    This is so tempting. Since finding a Stoddard-Dayton motor would be near impossible I keep picturing this chassis as a wonderful home to my Big 6 cylinder Wisconsin T-head. But alas its all in the ever maddening and mercurial timing/funding continuum. It would need to be sub-framed to fit the mounts and the springs upgraded and the frame strengthened to carry the weight (the big T-head weighs a hefty 1,575 lbs.) I am sure for the appropriate cash outlay a suitable period correct transmission can be found. This gem is mounted on a Chalmer's chassis... I hope this wonderful set of "bones" finds a good home!
  3. Terry Harper

    Got an old photo of you as a kid next to a car?

    Not a car but one of my favorite photos from my youth. Circa 1926 10 Ton model NW Lombard Hauler - Churchill Depot, Maine July 1974. I begged my Dad to let me take it home but..... Same machine Maine State Museum, 2015. Got to play in it again 41 years later.
  4. Terry Harper

    Using 3D technology

    Here is another project I did last year. I had to (wanted too!). A friend needed a magneto coupling for a Wisconsin T-head. For a number of years Wisconsin used a proprietary design developed by one of the firm's founders Arthur Milbrath. I had to reverse engineer it using patent drawings and measurements of some surviving pieces. Again the parts were modeled in 3D and a set of shop drawing created. (I also 3D printed a mock-up) Like the valve shrouds I used Fusion 360 to generate the machine setups and tool paths and milled the patterns out using the Tormach 440. Here is the exploded view of the assemply Here is the mock-up, shop drawings and pattern components. Once complete the pattern components were mounted on a match plate and are ready to cast. Here are the finished patterns which allow four sets to be cast at once.
  5. Terry Harper

    Using 3D technology

    That is very true. One thing to remember is that there is a fairly large community out there of folks with "backyard foundries" These are a mix hobbyists and professionals who cast metal for the challenge, fun and their own projects. Most are very willing to to share their expertise and knowledge. Here is a link to a forum which is a great place to contact these folks through. http://www.alloyavenue.com/vb/forum.php In fact most of the casting I have had done are by a gentleman with just such a setup. He and his wife sell crafts at various venues and he casts items for it. He also casts and sells items to the Live Steam railroad people and for his own projects. He does demo's at museums and various events as well. Again, this is a hobby for him - not a vocation, he just enjoys it. When I have something to cast I supply the metal and patterns and we have a "foundry 101" day. Here is a set of patterns we created for the valve shrouds for a 1917 FWD truck. The FWD used the same Wisconsin model "A" engine as Stutz etc. In this case I used a CNC milling machine to mill the patterns and core boxes. So far Peter has cast a number of sets to help folks along with their restorations. Until a few years ago when I started this project I had no clue on how to do this stuff. But like many things we learn. That's the best part of a interest or hobby - you have the opportunity to learn new skills and like any skill once learned it can never be taken away.
  6. Terry Harper

    Using 3D technology

    I am currently working on the lower water manifold for my big 6 cylinder Wisconsin T-head (5-3/4"x7") This is the last major assembly I have to fabricate. Like everything else on this beast it was bronze fittings with brass tubing and disappeared many, many decades ago so we have been working on re-creating as accurately as possible all the missing bits including the intake manifold and upper water manifold - all of which are brass and bronze as well. A number of years ago I fabricated most of the patterns and core boxes for the lower water manifold but they just were not quite right. So... over the past few weeks I have been back at it. I started off modeling in 3D each fitting. I worked from sketches and measurements of originals as well as from silicone molds pulled by a friend off original fittings loaned by our state museum. For some reason Wisconsin decided to use a rigid connection between the front fitting and the water pump. There is a flanged pipe that connects to the water pump and slides inside the front fitting and is held in place with a big gland nut. Here is a photo showing what I mean: As you can see the angle and offsets are critical so everything lines up. The first step was modeling the fittings in 3D. Below is a rendering of the complete manifold. To give you an idea of size its 16-1/2" between the fittings. The connector pipes are 1-1/4" brass tube. With the models and the shop drawings done I 3D printed a mock-up of the front fitting to verify that everything worked. The 3D print got a little messed-up at the top of the curved piece. I forgot to turn on "supports" which creates a temporary structure to support any overhangs etc. Fortunately (it took 19 hours to print!) that boo boo didn't affect the fit between the block and the pump. I also didn't bother printing the gland nut. I also created all the models for the core boxes and patterns. These also will be 3D printed. Each fitting requires a five part pattern - 2 halves for the body, 2 halves for the neck/flange and a backer. Below is one half of a complete pattern on its backer. There are also two core boxes per fitting. In the rendering below I superimposed a complete core. In reality The cores are formed as two separate halves and are glued together after curing. The core boxes will be 3D printed as well.
  7. Terry Harper

    My 1910 Mitchell "parts car" project

    Joe, Given the skill we have seen you display here I am sure pattern making would come easy to you. Heck, if I can figure it out you certainly can!
  8. Terry Harper

    1926 Locomobile Photo

    I am usually not a depot hack fan. (aka model "T", model "A") But there is something to say about one made from a top tier automobile and I really like this one.
  9. Terry Harper

    locomobile 38 bearings zinc or bronze?

    Bronze backed Babbitt would be my guess. which would leave you the option of making or re-using the existing bronze shells or omitting the shells and going with a traditional non-backed Babbitt bearing. Interestingly I have come across one motor that had inserts that were completely Babbitt (see photo) This was for a 1909? Jackson. They used dowels to locate the inserts. However, I very much doubt Locomobile would have gone that route.
  10. Terry Harper

    My 1910 Mitchell "parts car" project

    That looks great Joe! Makes me want to get back to finishing my manifold - the castings of which are collecting dust on the work bench.
  11. Terry Harper

    My 1910 Mitchell "parts car" project

    Hello Joe, On your vane pump could you use a simple spring loaded bypass valve? Here is the drawing for the service pump for the Wisconsin. This is the lower half or service pump and the gears. Of importance is the passage on the upper right tapped 7/8-18 for a adjustable spring loaded plunger (note the offset cross-passages). When the pressure exceeds the set amount it forces the plunger back and allows the excess to bleed back into the pan. Its a very low pressure system (5-10 psi) more dependent on volume than velocity. While this looks like a complex piece it would be fairly easy to simplify and re-configure.
  12. Terry Harper

    3D Parts Printing

    3D printed metal parts are feasible and have been used from sometime in other hobbies such as the Live Steam hobby and some industries - I believe awhile ago one manufacturer received certification to 3D print certain parts for use in turbine engines. However, as pointed out it has to start with an accurate 3D model. I teach CAD and in particular we work extensively with parametric modeling and additive manufacturing and CNC technologies. The printing is the easy part! Its modeling the component and determining tolerances and fit that takes a lot of time which adds up to a lot of cost if your paying someone else to do it. Fortunately 3D scanning technology is available and works wonders when applied to reverse engineering and quality control. Recently I had a part scanned at the University Of Maine Advanced Manufacturing facility. Could I have it 3D printed in metal? yes. but the size of the print would make the cost prohibitive. The plan is to use the resulting 3D model to develop 3D printed/CNC patterns and core boxes and then use traditional foundry work to cast the finished part. It may sound more complex than printing the part but its more cost effective since with the exception of the foundry work I can do most of it myself. Here is a video: Here is a project we developed a few month ago and gives you a good idea of the work flow: Using patent drawings and measurements from original parts we reverse engineered a proprietary magneto coupling used on early Wisconsin engines (the big T-head watercooled models) Once the digital 3D model was created using Autodesk Inventor Professional, the shop drawings were developed and a mockup was 3D printed. The digital 3D model was than copied and modified to including such features as draft, shrinkage and machining allowance. We could have 3D printed the patterns but we chose to mill them out on the CNC mill so the completed files were imported into Fusion 360 where we added tool paths etc. than exported as G-Code to PathPilot which is the operating system for our CNC mill. Next its off to the foundry and then to be machined.
  13. Terry Harper

    My 1910 Mitchell "parts car" project

    Hello Joe, We all have varying degrees of "good enough" Some people are satisfied doing the least amount possible - others - like you, (and me to a more limited extent) have to do the job to the uppermost limit of their experience and skills sets. For some of us that challenge if you will and need to achieve perccision results is all part of the fun and satisfaction. For example I have a friend who has been building an experimental aircraft for the past seven years. Achieving a phenomenal level of craftsmanship and the act of building is a passion for him that trumps the actually flying! In the pragmatic approach are you really gaining any value by going the extra bit in this instance? Probably not. But, you are building a new manifold which is the perfect time to go just that extra bit more to correct a fault. The stud - yes - but I don't think I would worry to much about the ports being out of round. In fact, I am think about the same approach - plug the offending hole and drill a new one. Alan, I am not sure. You would think that each jug was gang bored using a fixture so they would be all the same. I do know that at some point they changed from a elaborate cast aluminum manifold to the assembled brass.
  14. Terry Harper

    My 1910 Mitchell "parts car" project

    Joe, I think that's rather typical. On my big Wisconsin, which is supposed to be high quality, one of the studs for the intake manifold on the middle cylinder block is way offset from the centerline of the port as well. The funny thing is almost every one of the PT series engines I have examined has the same issue - all the intake manifolds have the same hole enlarged and offset yet each of the blocks is supposed to be interchangeable.
  15. Terry Harper

    Speedster Builds.............

    Alan, I spoke to Don today. He's waiting for winter to end just like me! At this point a little global warming would be most welcome! In regards to the valve shrouds - As Don and I discussed, since there are some differences between the early and later engines I am going to 3d print 2 halves that I can ship out to you to try. I should have these on the way to you by the end of next week. Once we know that these will work Don can drop the patterns off at the foundry that's near him and get a price for you. T.