GrahamC

Spring has sprung and I am getting ready to out to the field for some flying.

Over the winter I had a couple of small projects on the go in order to get a couple of planes ready for the spring.

First picture shows an AP15 with a muffler. The muffler should look familar - it is a OS-40S 4 stroke muffler. It was not a direct screw in fit. The OS threads are M10 x 1.5 and the AP 15 needs M10 x 1. I made a new header pipe out of 10mm stainless tube threaded m10x1.5 on one end for the muffler and m10x1 on the other to screw into the AP15 (all screw cutting done on my lathe). I then but a bend in the tube using a simple jig in an arbor press. I also had to make a thin M10x1 lock nut as well. The control line venturi was also made in my lathe as was a split tapered collet and new prop nut in order to mount a MP Jet 40mm aluminum spinner. The spinner is sold for use with electric motors, is very well made is very light. This is the third ap15 I have mounted one of these spinners on and it works out very well. Looks better and runs more true than any plastic spinner.

On 10% powermaster fuel with 18% oil 50/50 castor/synthetic and MAS 8x4 prop 16500 without muffler 15600 with. The OS muffler while not quite as quiet as the original very restrictive AP15 can muffler is so far working out very well on this motor.

Second picture is a Norvel V7 converted for airplane use. Required making a brass cotter to hold the CS 061 throttle in place, split tapered collect and prop stud and nut to take an MP Jet 40mm aluminum spinner plus a turbo plug button and a modified standard Norvel 074 head. The picture shows all the little bits and pieces I made up for the conversion.

On the same 10% fuel noted above, an OS P3 turbo plug and Graupner 7x3 nylon prop - 16000 with a 6000 idle. This is after about 6 ounces of fuel. Two things I did notice, the fuel nipple of the CS 061 carb does not hold the fuel line very well and was prone to coming off and the engine runs with a bit of a wet nose. Now, the wet nose observation may simply be the fuel nipple leaking and I mis interpreted what I observed.

All in all, a good day of some engine test running (ran a couple of Cox 049's as well) after a very long and snowy winter. Being Sunday and the neighbours where outside enjoying the day I didn't mess around too long. They tolerate my occasional running sessions so I try not to over do it.

cheers, Graham in Ottawa Canada

Mr Cox

Nice work! That's what the dark winter is for.

(I'm not very found of large spinners though, I think the Norvel could do with a smaller one?)

Just a note on the CS carb. I found a fule line a TowerH which is 2x4 mm (if I remeber correctly) and that had a very nice fit. Also an airbleed screw can be fitted but it is a bit tight. Just drilling a small whole though will help with the low end.

On a converted TT07 I've tried OS#P3 and P7, I found the P7 a bit trickier to start on (colder) but it ran nicely once running. Can't decide which one to use yet...

ffkiwi

Graham-nice work on both-though I can't help thinking that you've replaced one minimalist AP 15 muffler with an equally minimalist OS one!

As for the V7 I am working on a similar project-but for F/F rather than R/C so I will be trying to see how big a bore venturi I can get away with, and simply use a smaller spinner on the 4mm prop shaft a la Cox. I'll make up something similar to a Cox Conquest venturi for it ultimately-after I've tried a few different diameters out. I have a turbo 074 head from Ronald Valentine plus a std plug adapter from Mecoa, so a lot of plug experimentation is on the cards. The V7 seems to be fitted quite well, and not as tight as some of the Revlite AMEs-and sports a bushed main bearing as well. I was a bit chary of the clutch plate housing but it seems to hold OK and with the front face knurled should make an acceptable- if not very elegant- prop driver. I think it will be quite potent on a Master 7x3 or APC 6.6x2.9!

'ffkiwi'

GrahamC

Thanks.

This engine is going on a Sig Nitro Rascal. The spinner included with the kit is about 38mm. I put a 30mm spinner on first and it just didn't look right so I went with the 40mm one.

I will have a look, thanks for the tip.

I have a variety of turbo plugs and intend to try different ones. I try to use 10% nitro fuel for all my flying including the small ones so I set my engines to use that. I like the fact that the turbo plugs are available in a variety heat ratings. I will have a try with several different ones and see what if any appreciable difference it makes for this application.

cheers, Graham

Raymond LeFlyr

My Feedback: (2)

I'm beginning to convert all my .049s over to turbo plugs. The three heat ranges are good. The prices are equal to or less tha Cox high-compressions (if you can find them). And last but way not least, the durn things are in every local hobby shop (since most of them specialize in cars anymore).

I have one of Tim's heads and a couple from Mecoa. No problems or complaints so far.

GrahamC

You are right on that one. Difference is the stock AP15 muffler is a rather constricted and resulted in a 2000+ reduction in RPM where as the OS on was only about 900. The AP was a bit quieter than the OS but the OS meets the requirement to have a muffler on the engine and does direct the exhaust away a bit better.

Sounds like an interesting project. I am going get a hold of one of Mr Valentines 074 turbo heads as well. I guessed when I made up mine as I did not have an old 074 plug to measure or compare. I think I got it in the right ballpark first guess. There may be some some gains to be made by playing with head gaskets etc. I am going to make up a button for standard plugs and see what I get that way as well.

I have two more of these V7 engines and will be making one up for control line use. I will probably use the prop driver from the AP15 as the back end diameter is the same diameter of the V7's crankcase's nose (for lack of a better descriptive name). All I will need to do is make a split collet to fit the crank and the ap15 prop driver. Incidentally there is about 5 to 10 thousands clearance between the crankcase and the back side of my split collect that mounts the spinner (ie the crank move about .005 to .010 in and out with the split collet, spinner back plate, prop and the rest of the spinner are mounted ). I used a phenolic washer from my stash of TD 049 parts as a washer between the split collet and crankcase front end so that I could if need be use a starter without worrying about wearing away the front of the crankcase. Haven't needed to use a starter yet so far 2 to 3 flip starts. I can see where you could use the clutch plate bit as a prop driver but as you say - not very elegant. Yes, it has the makings of a potent motor for FF use.

Incidentally, Lite Machines still has stock of these V7 engines $19.00 USD (no muffler, no head but otherwise complete including needle valve) they also have the copper head gasket/washers as well. ($1.99)

http://www.shopatron.com/index/113.0.265.282.0.0.0

http://www.shopatron.com/product/par...=1-48062/113.0

I call them on the phone rather than use the Shopatron thing.

Cheers, Graham