Cranking and running Norvel engines

Yeah, mine's gonna run good too. I ran it with a well balanced Cox 5x3 prop and it only spun up to 17.5k, but I bet with a few less shims and the right head, it will spin on up. I don't know where it should peak, but I guess about like the TD .049 range.

I tinkered in the shop today and took off the Babe Bee head and put the Norvel head back on it with 3 shims for further break-in. I'll remove more as I get closer. I washed out my fuel system and installed the spring and the same 5x3 prop. Gave it a coupe of drops of after run oil on the side of the piston. Tuesday is my day to when I can crank it again. I've got the itch, but if my wife will kill me if she catches me abusing my hand.

I posted in the FAQ over at RCU about my wrist-pin floating. http://www.rcuniverse.com/forum/m_3747976/anchors_11181266/mpage_20/key_/anchor/tm.htm#11181266

RknRusty wrote:
I posted in the FAQ over at RCU about my wrist-pin floating.

Don't worry about it -- it's normal. There is very little side force on the pin while running so it doesn't require much of a swage to hold it in position.

Here's what AndyW meant about rolling the piston.

Lay the piston on a smooth flat surface with the wrist pin vertical. Place a piece of music wire (I think 1/16" is better since it deforms less metal) at 90 degrees to the rod directly across the wrist pin hole. Now roll the piston so the wire is in contact with only one side of the hole and tap with a hammer. Do the same for the other side. This applies the swage to one side at time and reduces the force necessary for swaging.

That makes good sense. I also downloaded your post about the extended head bolts. That's definitely on my list.
Thanks ,
Rusty

yup, longer head bolts are a must. I popped one of the seemingly delicate stock bolts and just barely had enough material to grab the broken end and rotate it out. Definitely heat the whole motor when backing those out, or you can touch the side of the case by the bolt with a soldering iron, to just heat that area.

RknRusty wrote:Yeah, mine's gonna run good too. I ran it with a well balanced Cox 5x3 prop and it only spun up to 17.5k, but I bet with a few less shims and the right head, it will spin on up. I don't know where it should peak, but I guess about like the TD .049 range.

It should outrun your TD .049 and leave it in the dust...

The Norvel .049 is perhaps similar to a TD .049 on larger props but there is no piston balljoint to worry about on the Norvel and you can let it rev. The Norvel .061 is even more powerful...

Hopefully your engine is not run in yet, and can tolerate a higher compression ratio and give more power later on.

Rusty,

Is today the day you can resume prop flipping?

fit90 wrote:Rusty,

Is today the day you can resume prop flipping?

Ha! you caught me on my way out the door. I got my wrapped bandage off and just a big bandaid. On my way to flip... with the spring starter for the first time.
See ya a little later.

Good luck and enjoy!

fit90 wrote:Good luck and enjoy!

Yeah, um...damn. I'm stupified. I've never seen an engine run that fast. First I had a newly made MA 5x3 on it and the spring nicked it. So I threw it away and put an APC 5.5x2 on it and tightened up the mounting screws and that fixed it. I was having a tough time needling it, the o-ring is getting looser and looser and the venturi wobbles around and the needle spins when I let go. But I managed to get a tach on it at less than full speed. What I was able to read and hold long enough to believe it was 23.9K. With me holding the needle still it spun up a lot faster than that. It had to be way over 24K. I hate to ask, but is that even believable?

RknRusty wrote:

fit90 wrote:Good luck and enjoy!

Yeah, um...damn. I'm stupified. I've never seen an engine run that fast. First I had a newly made MA 5x3 on it and the spring nicked it. So I threw it away and put an APC 5.5x2 on it and tightened up the mounting screws and that fixed it. I was having a tough time needling it, the o-ring is getting looser and looser and the venturi wobbles around and the needle spins when I let go. But I managed to get a tach on it at less than full speed. What I was able to read and hold long enough to believe it was 23.9K. With me holding the needle still it spun up a lot faster than that. It had to be way over 24K. I hate to ask, but is that even believable?

Yes they are very numbers for a Norvel on a 5.5x2

RknRusty wrote: It had to be way over 24K. I hate to ask, but is that even believable?

Sure, no problem on that prop, welcome to the +25000rpm club.

Just don't tell any cox TD owners...

Can't believe it ran that fast with all that stuff loose and wobbling,,amazing.

Old Nascar credo,,"loose is fast".. lol.

I have a composite purple speed prop that is a 4.6 x 2.8 that i got from Larry Kittinger,,hmmm

I'm going to unmount it and fix that loose venturi and needle. And most definitely order a test stand. I don't trust my wooden mount not to cause my death any more.

Back atcha Kris!

RknRusty wrote:

fit90 wrote:Good luck and enjoy!

Yeah, um...damn. I'm stupified. I've never seen an engine run that fast. First I had a newly made MA 5x3 on it and the spring nicked it. So I threw it away and put an APC 5.5x2 on it and tightened up the mounting screws and that fixed it. I was having a tough time needling it, the o-ring is getting looser and looser and the venturi wobbles around and the needle spins when I let go. But I managed to get a tach on it at less than full speed. What I was able to read and hold long enough to believe it was 23.9K. With me holding the needle still it spun up a lot faster than that. It had to be way over 24K. I hate to ask, but is that even believable?

No! Not believable! Me thinks you are fibbing.

That silly talk about being more powerful than a TD is borderline sacrilige too!

In all seriousness it sounds as if you hit the mark. Hope it works well for you in the future. Rock on with your bad self........

Ron

RknRusty wrote:I'm going to unmount it and fix that loose venturi and needle.

I had noticed that your needle looked a bit free in the video -- a couple of times the extension appeared to get into a harmonic vibration. Here are the pics from RCU on venturi and needle seals and the clipped NV.









Clipping the extension, if feasible, really cuts down on needle vibration and subsequent wear on the NV threads. A small nick filed into the knurled end will let you easily index it.

I removed my venturi this afternoon. I was able to press a fine threaded spray bar into the case after I opened the hole. The stock spray bar is .114". The other end is .009". My theory is the knurling on the spray bar probably has swelled the metal which is the difference in measurement. This wasn't a issue to Cox probably due to the molded plastic backplates they were pressed into. The closest number drill I had measured .1085". I was able to carefully and accurately open the holes as the bit just followed what was there for the venturi through bolt. I then used a piece of cylindrical steel stock approx 5/16" round and chucked it up in the drill press. I placed the case into a v block and supported it. I used the drill press to press the spray bar into the case. The knurling on the spray bar worked great and will prevent it from spinning. The spray bar has a shoulder on it that allows the spray bar to stop. The hole in the spray bar isn't quite centered but for pressure will work close enough. In the event you want to go back and put the stock venturi back in, press the bar back out and the stock bolt will still work. For running pressure, I doubt your going to see any better performance than this. Generally, my launch rpm is about 26500 using a APC 4.6 x 3. Ken

Ditto to Andrew's post. I use the fuel tube venturi gasket with fuel tubing over the needle valve on my Norvels. I have just had better luck with that. If you go to the fine thread NVA the needle has a lock nut. It is a pain in the butt until you nail down your needle setting.

I bet you were beginning to doubt us when we were saying it would be tough to get going but worth it once you got it going.

Bob

Yep, definitely going to tighten up the stock venturi. Once I'm satisfied with that, I'll put the pressure setup on it and get the hang of it on the bench. I saw that lock nut, good idea. I ordered a test stand from Bernie today.

I was talking of putting this thing on the Baby Flite Streak, but I might need to drag a brick behind it to slow it down enough to handle. The Junior FS is supposed to have a .41 engine, so I guess that's too much plane for the Norvel. Decisions decisions. I'll be building something for the MP Jet and the Tee Dee .09 too. I'm going to be a busy.

I subscribe to the you can never have too much power theory. I actually fly my Baby Flitestreak with Norvel power. I'm not on pressure mind you, but there's a lot to do to keep things mild. Propping correctly is certainly the best as you can let the engine rev and not allow the plane to go a zillion miles an hour. I certainly feel the APC 5.5 x 2 would do the trick as I use a similar setup on another model of about the same squares. Adding additional head gaskets is another good tuning device. I know your limited for space, flying on longer lines is a very simple adjustment to slow the plane down. You can also keep your nitro down, this can be problematic at times using pressure as the plug wants to cool immediately. Choking down your venturi area can keep things mild as well and this can be done several ways. Seeing what looks like an r/c carb on there this would be very easy to do. You could make a piece of music wire hook going from your engine mounting screws to the throttle arm on the carb. Ken

Ken Cook wrote: I removed my venturi this afternoon. I was able to press a fine threaded spray bar into the case after I opened the hole. The stock spray bar is .114". The other end is .009". My theory is the knurling on the spray bar probably has swelled the metal which is the difference in measurement. This wasn't a issue to Cox probably due to the molded plastic backplates they were pressed into. The closest number drill I had measured .1085". I was able to carefully and accurately open the holes as the bit just followed what was there for the venturi through bolt. I then used a piece of cylindrical steel stock approx 5/16" round and chucked it up in the drill press. I placed the case into a v block and supported it. I used the drill press to press the spray bar into the case. The knurling on the spray bar worked great and will prevent it from spinning. The spray bar has a shoulder on it that allows the spray bar to stop. The hole in the spray bar isn't quite centered but for pressure will work close enough. In the event you want to go back and put the stock venturi back in, press the bar back out and the stock bolt will still work. For running pressure, I doubt your going to see any better performance than this. Generally, my launch rpm is about 26500 using a APC 4.6 x 3. Ken

Ken, That looks like a great idea. It also looks like you did a super clean job executing your idea. I hope you are not offended if I try that myself in the future. It looks too good to pass up.

Bob

I have a Norvel with no carb and spare 190 backplate I think I'll give it a try too!

nitroairplane wrote:I have a Norvel with no carb and spare 190 backplate I think I'll give it a try too!

Hey! What did you do to my Norvel?