MJD

My Feedback: (1)

If cowled dirt not so bad, and this thing floats so speed is not high. I have no running or idle problems to date on a new Magnum .15 inverted. It runs same as any other setup that I can tell.

Another less common but possible setup is angle the engine to the left side and slightly down, muffler up and allowing the muffler to clear the fuse and lowering the carb c/l.

MJD

My Feedback: (1)

Snow is here, out come the projects..

- wing ready for finish, ailerons lagging behind in the rough
- reinforcement on the tail surfaces, and I made a new fin to the original profile, though alas no rudder on this version
- now grafting on the top of a .15 speed cowl, much easier than starting from scratch
- some filler, tri-stock and blending work to clean up the nose and blend the cowl to the fuse
- I'll leave the pipe out like this, not worth cowling it and it looks trick


The MDS .15 has a Rossi rod, Profi "nitro" head button for 10% fuel. Profi F2A pipe gave an instant +3k boost from the stock pipe. Elevator and aileron servos are in, weight so far 18.2 oz. Should hit 23-24 oz, about like the original, though it might be a bit quicker.

aspeed

Should keep up your heartrate. Will you use a shutoff or be a man? I had thought of a cowl using a bit of aluminum sheet bent like your cowl except open at the front and clipped on to the motor. Oh, where did you get the rods?

MJD

My Feedback: (1)

I'll definitely put a shut off on it, might use in-flight mixture control. I got the rod from Bill Hughes, when I ordered a bunch of OPS parts a couple of years ago.I should probably edit my statement to say I am pretty darn sure it is a Rossi rod, but I could have forgotten what he said it was, but it was definitely a better rod. Seems rods tend to surface in any discussion about weak spots on MDS engines.

aspeed

Just wondering, because I have a couple MDS .15s too, and a Supertiger X .15 which cracked the rod on the first run. I think they are all the same? I know how to get in touch with Bill if I need to.

MJD

My Feedback: (1)

I'm not up to speed on rod lengths, crankpin dia etc. But it seems there are some interchangeable parts among the 80's/90's era 2.5cc speed engines. I presume some copying of the dominant engine of the time was going on, Rossi?

I have an ST X-15 RV given to me years ago by a buddy, still looking for a venturi/NV assembly. Has the tight 90 exhaust adapter with a megaphone extractor. I imagine it will be hard on the ears. Love the looks of the engine.

aspeed

I think you will need to make a needle assembly. There are not many around. It would be pretty simple. Just a screw holds it in, and a pressure nipple with a remote needle from anything would do the job. Is it the one piece case or two piece?

MJD

My Feedback: (1)

Oops, it's a G15 RV, got the model number wrong. But yeah,m I can turn a venturi for it no problem, just hoped to find an original.

MJD

My Feedback: (1)

Some photos from today's flurry of progress. Next step is trowelling epoxy/microballoons into all the nooks and crannies. I was vacillating before tackling the woodwork on the cowl bottom, but a plan came together and it went smoothly.I'm going to machine the spinner ring off the hub, and use a 1-1/4" Al spinner (gotta get one). Here I taped on the front of a 1-1/2" plastic spinner to round off the nose. Wing fillets to do yet also. Elevator linkage is internal, with a ply hatch on the bottom that also mounts the tail-skid. Everything here, including battery, esc and switch, servos, minus tank and linkages = 21.8 oz.

Pond Skipper

Looks good Mike are you going with a aluminum spinner?

MJD

My Feedback: (1)

For sure, Brodak 1-1/4" Al. I try not to use plastic spinners on anything these days with the exception of maybe parkies. I just taped that on to give it a round shape for the photo, have to order the spinner.

cbaker65

The plane looks great ,but isn't that type of engine cowl going to restrict air flow to help keep engine cool?

MJD

My Feedback: (1)

That's one of the next steps - once I get the cowl all filled and blended in, the next step is to lay out the cooling inlet and air inlets. These will be done in typical c/l speed fashion. The air outlet will be the pipe opening in the rear, which is only roughly gouged out so far. I did the .65 delta the same way, and it runs happily for 2.5 minutes without signs of overheating.

MJD

My Feedback: (1)

Fiddling around on the bench, it looks like the Conquest .15 is a drop in replacement, and assume that with the CSTKAM .15 being a Rossi knock off (or so I read) that a Rossi will drop right in as well. But they never seem to go for less than about $300 in the classifieds. I wonder what other engines are a direct mounting swap.

cbaker65

Ah ,yea I kind of figured you was going to put some breather holes in!....

Normally I do surface rides ,I been lurking in the plane section because I just recently acquired some old CL's
an the way one was built ,I'm quite sure it can be modded into RC!...

I just lookin an seen your nice build!....

aspeed

Our speed models just had a bit of the head sticking out for cooling. Some guys would also have a slot in the front, and some stunt guys would make channels and all kinds of stuff.

MJD

My Feedback: (1)

I bought a standard A speed top from Steve Wilk and chopped the front off it (wasn't planning to build a speed ukie right now), and the cylinder shroud is tall enough to cover the head and plug. I'll be careful to baffle the inside to make sure there is flow squeezed around the cylinder and over the head. For the longer engine runs on RC gotta pull the heat away, no pan for heat soak and no taking a break after 30 seconds of run-time.

Further thoughts.. I masked the wing and did some Epoxolite fillets last night, and while sanding those and admiring how thing were coming along, I realized how much extra room there is in the cylinder fairing. It clears the tip of the plug and is large enough in diameter that it'll need some packing to baffle the air through the cylinder fins. Now I have to race to finish the front end before I get obsessive and decide to make a shorter, narrower, cleaner cowl.. Just finish the airplane dumbass, finish the airplane..

MJD

My Feedback: (1)

This should be a fun little test bed for a number of .15's with the same mount pattern.

Hmm, a racy canopy and turtledeck, add cabanes and make it a bipe, LG, open bay wings not fully sheeted and a throttled .15..



It fits - just - a 4oz Jett slim bubblefree tank, the tank reaches the firewall and extends about a 1/3 of the way back into the wing bay. It leaves about 1/8" of F2 each side to fit, but that's what Dremels are for.

Pond Skipper

Should be fast for sure Mike, dare I say post a vid when you can ..
You are about 4 vids in the hole so far lol.

MJD

My Feedback: (1)

4 videos, 3 airplanes, what else... yeah I am behind. Ambition versus reality. But the process is still fun..

Pond Skipper

Yes building is truly 1/2 the hobby, designing, planing out the parts leaving the rest for
good old fashioned flying and crashing ..

MJD

My Feedback: (1)

I suppose the saddest example is the little Scat Cat.. although 15" span models aren't necessarily faster to build. I might have to recover the wing, it's pissing me off a bit but is "okay". The toughest part is the aileron linkage arrangement I dreamed up (er, nightmared up possibly), which is where it sits now awaiting patience and attention. But of course it will be ready for the next warm weather.

This one has me stoked, mostly because it's a slightly less than sane kit bash and serious hp upgrade that promises to come out within a couple of ounces of the original. And because I have everything drawn in CAD as I go, meaning reproducing it will be no problemo. I'm already scouring the classifieds and auctions for a Mk1 Rossi.

I think once all is said and done in the engine compartment and the ply all sealed up, I will set the motor mount in place finally and likely epoxy/microballoon it in place to the sidewalls etc to make it all one homogeneous lump. If this was the only engine that would fit in the mount then maybe not.

Pond Skipper

Yes was a bit of a task to use torque rods in such a small craft. I was
happy to do the last 3 TD .010 planes with direct link, dirty but in the
blast of the prop. Check ebay on the engine I have seen 1 perhaps 2 in the
last 3 or 4 months.

There is this up for grabs...
Rossi Series 1 15 Control Line Gas Model Airplane Engine – with tuned pipe 2.5
Chilliwack, British Columbia, Canada

http://www.ebay.com/itm/Rossi-Series...8AAOSwZQRYaE~U

GREG DOE

Mike, I dug out a Rossi, a Cox and a Nelson .15 yesterday and they all have the same bolt spacing. The crankcase's vary slightly in width, with the Nelson being the widest, so you might have to hog out the motor mount beams slightly, depending on which engine you start, and finish with. I enjoy following these projects. Greg.

MJD

My Feedback: (1)

Thanks Greg. If you ever get the urge to thin your flock of old speed .15's, hey keep me in your thoughts..! In terms of open exhaust timed examples, I have a Ron Young Cossi, but I like piped engines on these silly projects.

I like the looks of how this one is coming out, and being pleased with the outcome so far I have started drawing the modified .15 nose parallel to the stock fuselage and adding in the bits I improvised along the way. By improvised, I mean drew them in CAD off to the side in the drawing, cut them and test fit, repeat. They seem to work so looks like it can and should be reproduced, with some minor adjustments now that I've done it once.

Brad - I think I have all the eBay examples in my watch list right now, that one for sure. I've checked the classifieds here and various theres, and today was scouring the Delphi speed forum. I know there is one hanging on display at one of the LHS's, and the owner likes my little oddball projects. I'll have to pitch him on it next time I'm there.