Double Star .60bb Side Exhaust

This is a Super Tigre .60 clone, except it has an AAC setup (no piston ring), and is made in Moldavia, imported by Tom Dixon, and sold by Dixon, Windy U., John Brodak and others. The price is rather steep at $250, but perhaps Leonard can give a small discount on them. I bought mine from "Warhawk", aka Col. Hoyt Hawkins, USAF Ret. The engine had been run 3 runs on the bench.

As delivered, the NVA has a tiny "banjo fitting" for fuel hookup...rather neat, but I felt a complication when cleaning out a clogged NV (and more likely to clog), so replaced it with a Randy Aero (PA) NVA, from Leonard. Nice NVA. The engine comes with slotted head screws, sort of a panhead, with shallow slots and not very accurate threads. They are 3mm x .5 mm, 8mm and 12mm in length. This is the same size and lengths used on OS .40/.46 LA's and various Magnums in my stash, so I got boxes of each in socket head machine screws. The muffler screws are same, 30mm long, got a couple of spares. Speaking of the muffler, it is a nice, small and light tube type muffler with a "venturi" style design. Air flows in at the front and out at the back, along with the exhaust. The rather interesting spinner is small OD and our props may not fit inside. As the engine was going into an existing model with a 2" spinner, I left the DS unit in the box. The interesting feature is that even with the spinner setup on the engine, the prop sits on the knurled prop driver. There is a large bore in the spinner backplate that sits in a step cut into the outside edge of the propdriver, so it is slightly loose until the spinner cone is installed. I found that I could modify my Tru-Turn/Dave Brown spinner backplate to work perfectly. If you want to do this, email me and I'll explain how...yup, you need a lathe. <[email protected]> I then needed a Dave Brown 1/4-28 short spinner adapter, but had to modify it slightly also, and had to make a stack of 1/16" aluminum washers to put under the adapter. This was getting annoying. Hopefully, this has been improved by later production mods...a 2" spinner should be standard.

There were no instructions or parts list in the box, much less a warranty. As the engine came to me slightly used, I am not sure if these would just be missing or never existed. The "box" is made of high density styrofoam, form fitted. It works, but is not my idea of wonderful. However, my DS .40 came from Brodak in a plastic bag with a label stapled on. Brings a whole new meaning to "NIB".

Finally installed in the model, and out to the field, I installed a 12-6 APC and a Thunderbolt 4-stroke plug (Dixon's website suggests a very hot glowplug), filled the tank with Powermaster 10% x 22% castor-syn. blend. A bit of tank height adjusting, some needle tweeking, but no other fussing, and it ran like Jack the Bear. After about 10 runs, I switched to a 12.5 x 6 APC (full, not a cut down 13"), even better. Launch rpm is 8.8k and doesn't seem to require any tweeking from flight to flight. It has started first flip several times, tho I typically use a starter. When I pull it through and get a good bump, one flip does the job. So far, with about 15 flights, it has a very nice 4-2-4 break, lots of power and not a lot of vibration. Though it would be nice if it came ready to bolt in out of the box, it is a sweet runner, and I would highly recommend this engine for a Legacy, Impact, .60 Cardinal, Strega, SV-11, etc. To be completely fair about it, I have gone through similar exercises on most of the engines I have used in the last few years. Made venturis, changed screws, backplates, mufflers, setup spinners. The spinner setup is the worst hassle of the lot. Mine will all work like the DS setup from now on, as there's less chance of having the prop/spinner come loose. I'd hate that. Steve

>There were no instructions or parts list in the box, much less a warranty. As the engine came to me slightly used, I am not sure if these would just be missing or never existed. The "box" is made of high density styrofoam, form fitted. It works, but
>is not my idea of wonderful.

Made venturis, changed screws, backplates, mufflers,
>setup spinners. The spinner setup
>is the worst hassle of
>the lot. Mine will all
>work like the DS setup
>from now on, as there's
>less chance of having the
>prop/spinner come loose. I'd hate
>that.
>Steve

Hi Steve, I have a DS60BB that I bought from Dixon a few years ago. The serial number is 089. It would be interesting to know if yours is a more current version than mine.

Mine came with socket head bolts, a ST style needle valve assembly, and a very nice light & small closed-front tube type muffler. There were no instructions, warranty information or spinner. My engine is jewel-like in appearance so it is good to know they run well.

I'd be interested in receiving your spinner mod info.

Eggy

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1) This is not a production method, but time/labor intensive. Stick a short chunk of aluminum round stock in your chuck and face one end to clean. Reverse, putting that face against the chuck and tapping it home. Turn a "nest" or "spud" to fit some feature of the part in question. Then the part is glued to the fixture with a thin coat of Bondo, being sure to have it fully seated. I do this by using the tailstock to push on the part via another chunk of scrap aluminum or plastic. Bondo sets up fast, but takes awhile to get full strength. Avoid heating the part with your cutting tools (use sharp cutters and be gentle/slow), as heat is how you break the bond later, using your heat gun. A piece of wood or plastic can be used to help break the part loose, in addition to heat.

2) Sequence of setups: If your prop driver doesn't have the step (shown clearly in Eggy's picture), you need to do that first. Not a lot of material is required behind this step, as the spinner cone will actually pull the backplate up against the back of the prop hub. If the prop driver is driven by a ST-style collet, this is easy enough. I did a Magnum XL .28 prop driver this way: Took a piece of 1/2" aluminum rod about 4" long, faced both ends and put a #3 center drill dimple into one end. Then I put another piece of 1/2" rod into the chuck and turned a diameter and shoulder to the same dimensions as the crankshaft/collet. Slide the prop driver and collet onto this and push with the first part we made, using the live center in the tailstock to push. Be fairly gentle with the machining ops. If the stock prop driver is not suitable, you may need to make a new one or adapt one from another engine. I have never tried knurling a face, only a diameter, but this is a pretty heavy duty operation, which my little lathe at home would not like. You want to machine a ring about .06" x .06", the diameter doesn't matter a lot, but you will have to bore the spinner backplate to slip fit.

Next, I want to work on the prop side of the backplate. To hold it, find a chunk of aluminum roundbar big enough, longer than the lathe chuck jaws plus some. Face both sides, and seat against the
chuck face. Turn a bore to fit the outside diameter of the s'backplate about 1/8" deep and relieve this another 1/8" or so, leaving a 1/8" to 1/4" wide land to seat the s'backplate against. The s'backplate will be glued into the fixture with Bondo. After machining, a heat gun and a little persuading and it will pop loose. What you need to do here is machine off the knurling that normally goes against the propeller hub and bore the hole out to fit the diameter you turned in the prop driver. This need not be a press fit. When you assemble all the bits, the spinner cone screw will tension the backplate against the back of the prop.

Measure the thicknesses of the s'backplate and make a complete dimensioned sketch of the cross section, so you'll know what to do next. You need to face off the knurling on the engine side and also counter-bore that big hole so that it will clear the body of the prop driver. If you can remove some material to lighten the backplate, now's the time. Be sure to leave enough material where the lip of the spinner cone indexes to the s'backplate. You need to make another fixture out of more aluminum bar, and Bondo the part on. You can index off the ID of the spinner lip or the bore you just did. Either will be plenty good, this operation is non-critical for concentricity. Getting the thickness of that lip (depth of counterbore) is important, as is getting the part nested completely so the faces are parallel. You want the lip to be thin enough so that the prop sits on the prop driver and not the s'backplate. A clearance of .010" is about right.

Common sense says that this will require moving the engine forward in the mounts, but if your engine has the neat ST-style collet drive, you can also whittle up an aluminum shim to move the prop driver and spinner forward.

At this point, you have the prop driver, s'backplate and cone ready to go, but you need an adapter. I like the Dave Brown items best, tho Tru-Turns work fine. The Chinese spinners have plated brass adapters and metric screws, which work, but brass isn't as strong as steel and the metrics can be a hassle. I have had to tap the 1/4-28 out with a bottoming tap, and also had to slightly shorten the nose of the adapter for thick hub props (APC's). You may need to make some aluminum shims to go between the prop and adapter/washer, to get the adapter to tighten down on a thin hub prop. I would start with sheet aluminum, .032, .040, .062", then double-drill holes to fit over the crank thread, saw out blanks, and stack them on a setup much like used to rework the prop driver. I have also drilled out the hole and enlarged the counterbore in the spinner cone, using the aluminum bar/Bondo trick. When you get the parts all finished, you should be able to bolt it up and go fly! Put those extra aluminum shims in your field box, as you may want them at the field if you change props.

That's all there is to it. Luckily, it's a job you only need to do a few times a year, as it's a pain in the hindquarters. Well, you asked, Eggy! Steve

Eggy

This is another one of the stunners one comes across in ex-Soviet Bloc countries.

The truth of the situation is that you and I can visit any Tacoma Screw Products (no jokes from those outside the NW, please) outlet and have ready access to fasteners superior in quality, selection, quantity, and availability than any model engine producer in those countries.

Get this: About 1991 or '92, Eduardo (a.k.a. Edik) Kozlovsky came over for a Bladder Grabber and a couple weeks fixing Carver's bashed AMA models. While here he and I went to Tacoma Screw, Ed spending a goodly sum on 4-40 cap screws, 4-40 taps and the appropriate hex keys. He took them home to sell to fellow F2D fliers, slotted head screws such as they had access to being a huge pain in the rear.

While it is true that I had an account with supplier, thus saving Ed some money, it must be noted that he was taking his stock back to a country which at that time was paying pensioners the equivalent of less than $15.00 a month. Even at what must have been outrageous prices he reported no problem in selling all of the machine screws and associated products.

Now do you want to hear about the difficulties in making taps for engines destined to use Cox glowheads...??!! Or how about dies to use in production of Nelson-plug adapters for 1/2A motors??!!