Member postings for Roy Vaughn

Yes, I have seen a number of build threads or videos which suddenly jump from a rough machined liner and no piston to a running engine, missing out the most critical and interesting operations! I have never used a pressed-in pin, it always seemed a recipe for trouble due to the difficulty of getting the interference fit correct. Whether the fit matters depends on how much and how hard you intend to run it of course. Good luck with the project.

Roy

There was a link on Adrian Duncan's page of engines for home construction but it no longer works for me. Maybe it will for you. If that fails, pm me and I'll forward my copy. Roy

https://adriansmodelaeroengines.com/catalog/main.php?cat_id=214

The standard Clough42 ELS only replaces the lead screw, as described in the first video of his series. However, additional functions have been added by others such as driving to a stop. Some are described in the Issues list on Github. There are other ELS designs which have more functionality I believe but I have no detailed knowledge of them.

Re parts availability, James seems to have more or less abandoned Ebay for his online shop. He used to sell a kit comprising the interface board (still available) and parts for the control panel. The latter is no longer in the shop. In his last ELS video a couple of months ago he talked about replacing the current setup, which utilises a cheapo control panel module, with something better (more reliable and less prone to interference). I suspect that he has run out of the old kits and is waiting until the replacement is ready. This need not hold up construction of your own ELS because the use of his front panel is optional, mine doesn't use one, just purchase the interface panel from him and buy the control panel module off Ebay. In fact, get a couple in case the first doesn't work.

It may well be cheaper to purchase more change gears to get the pitch you need but the ELS is far more than that. No more messing around for ten minutes with oily spanners just to cut one thread, it's a boon.

Roy

It was a new flat top piston Keith, sorry I didn't make that clear. I can't remember exactly the thinking, maybe along the lines of, well, my PAW 2.5 Goodyear engines are very powerful and they've got flat topped pistons. Also, they are easier to make!

Neil, interesting observations about oil in PAWs. My experience is a little different. We went through a period of using 12% ML70 with satisfactory results until Tony Eifflaender advised that castor was quicker. I tried our Nelson fuel with 10% castor and he was indeed right. We carried on with this percentage with some success! All the piston-liner fits were pretty loose so that may have helped.

Roy

Tug, going a bit off topic, I'll PM you, Roy

Hi Tug. The contrapiston can sit anywhere in the bore so all that's needed is a longer comp screw, it wasn't an issue on my motor.

Re glow fuel, I'd be wary with the stuff in model shops nowadays, there are a lot of low/synthetic oil blends about which probably don't suit older motors. It's difficult to find out what's in them and how much of each ingredient.

Roy

I don't recommend the integral finned version. I made one for a derivative design I'm working on at the moment and it weighs about an ounce and a half! OK in a display case but I like to fly mine.

The piston fit on my original Viper, made with the conical piston, was a bit iffy so I made a new one but with a flat top. The edge of the piston governs the timing so it's OK to just chop the cone off, no mods are needed to the liner. This has several advantages including lower reciprocating mass and easier manufacture. The contrapiston can be made thin-walled which is a boon for fitting.

Roy

I think the main reason for using bearings of different size is to make it easier to maintain the spacing of the inner bearing rings. Without a stepped shaft the front inner will be prone to moving around unless it's an interference fit on the shaft or there is a separate spacer to set the distance as in the FMV. The Viper was intended as a competition engine so this might have been a consideration. Mine manages 14,400 on an APC 8x4 on 20% castor fuel, I'd be interested to hear how yours performs. Roy

Thanks everybody for your comments. Thanks Bill for digging out the Dan Gelbart videos. I think I've seen them before, what a workshop. The modus operandi of his device is similar to what I envisage but I don't aspire to the same level of precision! Its primary use would be on the mill but, as he says, it could be useful anywhere. The integral units are rather low resolution so on balance I think the way forward is to buy the best-looking cheap USB camera and see how it goes. Integral LEDs should solve the lighting problem. Thanks again.

I do mostly small scale machining, e.g. current project 2.5cc diesel. I often find it difficult if not impossible to see clearly what's going on at the cutter location using head mounted magnifiers so I'm wondering whether an inspection device such a those sold as borescopes would be useful?

Perusing Ebay there seem to be two main types available at affordable prices, USB devices which plug into a phone at £10 or less and self-contained devices at around £40 or more. I know nothing about this sort of kit so any experiences or recommendations would be gratefully received. Thanks

I don't know whether he covers this exact topic, but Doubleboost on YouTube has a series called Dti Care and Repair with Bob which might be of help.

I don't know whether he covers this exact topic, but Doubleboost on YouTube has a series called Dti Care and Repair with Bob which might be of help.

The problem with my gib with spherical end screws arose because the dimples are too shallow and the contact was assymetric, forcing the gib into two lines of contact. The points are a bodge of course, a smaller radius hardened tip would be better but I just wanted to get the job done in a hurry. A better solution would be to drill the holes deeper to ensure symetrical contact with the original spherical tip, but setting up to drill accurately might be a pain.

Roy

I second what MikeK has said. I've just been through this with my X2. I machined the gib screws to a point which improved things a lot.

Thanks Emgee for reminding me about the manufacturer's documentation, I've actually used it a couple of times to date. Having had another look it's better than I had realised, especially the embedded video tutorials. I've just spent a happy hour or two learning more about constraints.

The problem I have Henry is getting stuff to stick in my old brain. It helps now that I have a second screen on my PC so I can keep reference/tutorial material open at the same time as Fusion 360 so that I can more easily go back to remind myself again about what I've already forgotten! I've been using Paul McWhorter's videos and they've been very useful as a starter. Continual product updates to user interfaces is a modern curse unless you are selling training.

Thanks chaps. I can stretch to the cardartifex book fortunately. At the moment the only place in the UK selling the new 5th edition is Amazon, which I refuse to use, but I will pick up a copy when there is an alternative source. Thanks again.

Has anyone on the forum bought a book on Fusion360 recently which they could recommend to a beginner to 3D CAD? I know about the online resources but I like to have a textbook or two about subjects new to me to relieve the tedium of online reading sometimes. Anything before 2020 I believe will be out of date because of modifications to the user interface. Thanks in advance.

Judging by Sealey's web site your mill is the same model as my Sieg X2 Axminster version. I have a capacitative scale fitted across the front the table, it's never been any trouble. Many years ago I bought some drawings off the Internet to save time designing a mounting arrangement from scratch but I've no idea where they are now unfortunately. If you want some pictures of the installation pm me. Roy

With some trepidation I ask, have you put the power supply links between the USB section and the main board in place? Roy

John, sorry to hear the troubles you are having. The approach I took to building the system, which worked first time, was to start with the components on the bench connected directly to one-another, this eliminates the considerable uncertainty introduced by connectors. Build the system up step-by-step, e.g. start with Launchpad powered by the USB (and everything else disconnected) and do the download, then add the boost board, then the Lauchpad external PSU and other components incrementally. Maybe this is what you have done in which case apologies. Make sure the Launchpad switches are set correctly. Also, be very careful with the download, it can look as if it's worked when it hasn't. When cabling the system up in its final packaging with connectors, check continuity of individual signals end-to-end with a meter as you go. Check and recheck that power supply polarities are correct! It's a pernickety business but you'll be delighted when it's running. Hope this helps, Roy