AME/Norvel .15 bb

RknRusty wrote:Definitely do not spin it cold with a drill.

I cannot emphasize how important this advice is. I have several .15's that are squeaky tight at the top, much like the Q40 pylon engines. The entire process described in the SH post is to break them in, not wear them out. You do not want to remove the pinch cold!!

Thanks for reiterating that, Andrew. I should have given you credit as well for the knowledge I'm passing on.
Rusty

Jim, Doug will make you a head button for the engine. My father made mine but he's currently retired. Do you have the wrench that tightens the head button? Surfer Kris shows his engine and his retaining ring is different than the one on my engine.  Here's a picture of the wrench  http://www.nvengines.com/index.php?page=shop.product_details&flypage=flypage-ask.tpl&product_id=74&category_id=7&option=com_virtuemart&Itemid=65

Funny thing about OS products on Tower's site. When the items begin to be purchased in quantity is when they become discontinued. I've seen this many of times especially when the Tower .40 was available. I know someone there has to question as to why this needle valve is so popular. Everyone I know in combat runs this particular needle assembly.

          I strongly recommend losing the muffler and avoid using it for break in unless it's required like at my flying field.  Like just about all stock mufflers it suffers the same fate. Far too heavy, restrictive, the mounting clip also lacks in keeping the muffler tight. I sound like a broken record but it probably works for the r/c crowd better than control line. OS made many types of needles for their r/c engines. Type #2 will also work but it's a lot touchier to adjust if your running the engine on bladder.

I would break in the engine using a 7x4 as the largest break in prop. I highly recommend taking the engine apart and washing the internals out prior to running. I also recommend lapping the head button on a piece of glass using sand paper and oil.  I've seen many of these leak badly all around the threads which is why I suggested using Ultra Copper around the threads. I ran mine for just a few minutes at a time and let it cool down in between runs. It helps to use a heat gun to heat the cylinder initially as the fuel will lock up and pinch the piston at TDC. My initial runs within the first 20 minutes took out the plug. Keep an eye on that as you don't need a piece of the filament getting jammed in the cylinder.

I've also run this engine on 40% nitro with no need to do anything to the engine aside from propping it accordingly. It runs terrifically on SIG 35%. Ken

Ken,
I purchased the wrench with the motor. What do you mean when you say prop accordingly with 40%?

Jim

Ken Cook wrote:
          I strongly recommend losing the muffler and avoid using it for break in unless it's required like at my flying field.  Like just about all stock mufflers it suffers the same fate. Far too heavy, restrictive, the mounting clip also lacks in keeping the muffler tight. I sound like a broken record but it probably works for the r/c crowd better than control line.

We used the .15's a lot for R/C combat and mid-airs were inevitable. The muffler retainers, both the clips and spring retainers, were almost useless, so we always safety wired the muffler to the engine. Even if it got knocked loose, at least we didn't lose it in the field. Everyone ran mufflers, not so much for noise restriction since our field was well out in the country, but for muffler pressure since flight attitudes were all over the place.

Jim, whenever you run bladder pressure certain factors come to play.  The needle is very critical and having one with fine adjustment is a must. Another factor  in particular is prop choices. We run small props on bladder pressure due to it making the engine needle easier. For example, a 8x4 prop on this engine is too much prop on bladder pressure on a .15.  We run 8x4's on .25's.  The 6.3x4 or smaller works far superior. When I say smaller, I was using 7x4's initially and I started to  clip  them  down until I settled on 6 1/4"  or the Russian glass props. Russian glass props take a bit of experimenting to find the correct one. They're typically colored and some of them are close in color but aren't the same pitch. The pitch on the Russian props are considerably lighter than commercially available props. The difference is that they work far more efficiently but this also requires them to be turning up higher. I would see 19-21K using the Norvel .15 on bladder with the venturi opened up. We were seeing identical results in rpm's using the OS FP .15 bushed engine which really was impressive.   The Master Airscrew trimmed down and cleaned up yielded some good speed for me as well as the APC. The newer thinner Master Airscrew did work quite well. I wouldn't recommend the wider older bladed Master Airscrew.  I try and use the easiest commercially available prop available. I just break them constantly and like last weekend I broke 6 in our contest. No matter how the props were clocked on the plane, the high grass would grab the prop and break it. I don't know what your intent is in terms of running this engine.

Running high nitro doesn't mean the engine is going to be destroyed. It just means that you need to lighten the load on the crank by going slightly smaller due to the increased torque which is going to be on the crank. It needs to turn up. Loading it down with too much pitch is generally going to break something. I've toyed with the idea of using the Norvel in clown racing this season. While my LA .15 took the gold last season I was looking for a bit more speed and I think this would be a good choice.

Ken,
I will be using it in a perky. That means no pressure and I will be going for speed. I was going to try an apc 6.5x6.5 for starters and cut it down as necessary.

Jim

I have no experience with the Perky. However, I like your thinking as it's an excellent choice  with that prop size. I use that on my .15 clown racer.  I've seen your post on other forums. Paul Smith has chimed in. Paul is a incredible builder. I've raced Paul and he's handed my rear end to me. He has some unbelievably fast Perky's and I saw them in action at Brodak's. He's one heck of a competitor.  Have Paul send you some pictures. Frank Carlisle from Detroit built a Perky with the Norvel .15 but it may have been the Big Mig he was using. Here's Frank's video.   https://www.youtube.com/watch?v=Ppvgri5EMXo    This was a first for Frank as  he mainly flew stunt. Frank was a terrific builder. He's been out of the hobby for a few years now. There are many unknowns with Frank's video as he doesn't state line length or line diameter or prop size or nitro. I'm 100% positive that he had at least 20 mph hidden in the plane with some minor fiddling.  While Perky is not for all out speed, It really is about the most average combined speed in the Perky postal event. Paul uses two Perky's and one of them is well over a hundred using a Nelson .15. I know he had one catch fire and burn up completely. I saw the aftermath but he did rebuild it. Ken

RknRusty wrote:Definitely do not spin it cold with a drill. You probably read my Norvel Break-in post at SH, but in case not, here it is:
http://stunthanger.com/smf/index.php?topic=32566.msg324763#msg324763

I can't read that link, not a member...

Just run-it in like you would any other tight ABC engine. Never turn it over cold, especially without a glow plug installed.
Pre-heat the cylinder until enough of the pinch is gone for an easy flip over, then start it and run it in with plenty of castor (25%) in the fuel.

Fought this motor for about an hour and only got a few good fires on prime but no solid runs.

Jim

What was the problem?

If it is too tight at TDC you need to preheat the cylinder, then prime the intake and run.
A larger prop (i.e. 8x4) can also help for the very first few, short, runs.

Pre heated the cylinder until it was loose, 7x3 prop. I'll switch to a larger prop and try again.

Jim

On my lesser Big Mig, when new, I reduced the compression to finally get it to fire off and run. After that first tank, I went back to normal compression. Yours is supposed to have a pressure line to the tank isn't it? I don't know if that would matter on the bench, as long as you have a bit of gravity feed. Mine drove me nuts before the first successful crank, but then it was easy after that.

You could try priming with some 35% nitro. That's the only way I could get my MP Jet started with FAI fuel.
Rusty

Yes, one can use a few extra head shims in the beginning. Extra castor (to give 25%) in the fuel helps too. These engine can have a little funny behavior, if you over prime them the oil is washed away from the cylinder walls and then they really start to squeak...

Best thing then is to put straight castor directly on the piston to get an oil film back. Leaving them overnight with castor in the cylinder helps too. These can be finicky at first, but the reward is sweet.

This ones going to be fun. APC 7x3, sig 35%:

Nice numbers Jim.

I'm learning how to start this beast. 5 drops prime or she floods. I'm getting 18.5k with an apc 6.5x6.5. That's a theoretical 113mph. Emphasis on "theoretical".

Jim

I've never played with a .15, but I have a TT .15 on the slate for later this Summer. For the long talked about Hyper Viper profile clone. Can you just prime it like you do a .35ish engine; block the venturi and give it a few flips, then follow with a few open air flips?
Rusty

RknRusty wrote:I've never played with a .15, but I have a TT .15 on the slate for later this Summer. For the long talked about Hyper Viper profile clone. Can you just prime it like you do a .35ish engine; block the venturi and give it a few flips, then follow with a few open air flips?
Rusty

When this one is cold blocking the Venturi and flipping a few times works great. When it's warm any more than 5 drops floods it. My fox .15 also starts better cold.

Jim

JPvelo wrote:When it's warm any more than 5 drops floods it.
Jim

I've had engines like that. The TT is a little hard to hot crank. I don't have any idea why.
Rusty

Less compression when hot.

Yeah, I guess so. Better keep a little can of Ronsonol in your pocket. Watch out though. One time Wayne and I were having a starting problem and put a drop of that stuff in the venturi. He backed up the prop to flipping position and it hauled off and knocked the chicken stick out of his hand.  

I had my Fox 35 disarm me a couple of times before I ratcheted up my level of respect for it. And that was with nothing but plain old 5% nitro and gook.
Rusty