fiat

Hello I am from the helicopter forum and we use the norvel .074 in our little choppers. We are blowing these norvels all the time, my question is, Is anyone here useing the norvel .074 and are these motors holding up for you?? Also what cylinder temps are you running ??? Our norvel's are configured a little different than your airplane design and I wonder if this is the problem. It seems as long as they have been using these norvel .074 motors there has been this problem. What happens exactly is that the con. rods break, some sooner than others. I have killed 5 motors myself in just a few months. Thanx Alan

Lynn S

Are you using 20% castor oil? any synthetic would not be good to use.
It could be that this engine is not designed to for that kind of use. From what I have seen of helicopters they really seem to smoke a lot. It that from engine heat?

dennis

My Feedback: (90)

Well a few observations as I fly helis also and had the LMH Heli a few years ago with a Norvel V061.
Most heli fuels are 15 or 30% nitro and without exception are all synthetic oil of about 23%
I'm using Cool Power specs here.
The biggest problem is the start up and idling till they get to take off. Unlike a plane you just can't randomly hit the throttle when you start, it's dangerous having a rotor blade get out of your grip and nail you. Protracted idling without ever bringing the motor up to acceptable heat levels is probably killing the rods and the piston fit. Don't know what to tell them except start it up where your going to fly it and get the rpm up asap.
In defense of the Norvel though when the LMH first came out it had a special Cox TD heli motor. I guarentee you the crank did not live for more then 5 runs on the 6 examples that I saw , including the one on mine.
Dennis

gcb

Alan,

You might try breaking the engine in thoroughly on a prop before putting it in a heli.
Good luck.

George

fiat

I use norvels 25% with caster oil all recommended by lite machine and norvel. I keep close watch on the temps with an infered and tie the heli down so I can run up the RPMs right away. Lite machines keep telling me that the manufacturer is to blame for poor craftsmenship. This is why I asked on here if anyone here is haveing this trouble. Thanx Alan

Lynn S

I don't think anyone around here is having problems with them on airplanes.

Japanman

I`ve had mine do some pretty unlikely rpms and it is still just fine.

fiat

Thanx people for your input.. Alan

Keester

Generally speaking Norvel engines on planes have performed well. Durable, light and powerful. So it must be the idling issue or even heat. Most planes need not idle for long and have much more airflow over them once airborne. Also I agree with George Breakin would be critical for a engine that has to be in your heli.
Keester

fiat

As far as idle you people are kinda wrong there, a heli motor runs mostly around 1/2 to 3/4 throttle all the time we idle only when we start up and land. But I do belive it has to be the heat thing here, Doe's anyone here know what temps you are running at ??? I keep a close eye on kine because of the problems I have had. I run around 220f to 250f any richer and the heli will not lift. Maybe this is what our problem is ?? We set it up rich and then lean it till it just lifts off and leave it there.. I believe it's too small for the heli. Alan

Lynn S

Fiat,
I just went over the part where you said that you run the engines very rich then lean them out to where they will take off. The Norvel is very different from conventional ABC or other engines(alum. cylinder and piston). Running them too rich will cause the engine Not to break in. There have been many post on how to adjust the carb. but you don't want to run them too rich or too lean.
The piston fit is very tight at the top of the cylinder and it must wear in for a proper break-in. If the cylinder has too much lube then it won't wear in like it should. It is possible to run the engine a long time and it not be broken in if it is set too rich. It sounds like you are putting too much stress on the rod and that could be that it is not broken in properly. I would run this engine with a prop on a test stand for at least an hour or more total time before you put it in a helicopter. Many recommend using a heat gun to heat the engine before you start it during break in to expand the cylinder and piston.
Just an idea anyway. Lynn S

PS. I learned that I was running my .074 too rich at first and it would lock up and throw the prop.It was not breaking in. You don't want a rich setting, just go ahead and set the carb at a normal setting. I would think that once it is well broken in then you can see how well it holds up in the helicopter. If it still breaks then, I would use a heavier engine.

fiat

Lite machines tells ue to run the engine rich "4 stroke" for 2 minutes then lean "2 stroke" for 2 minutes and so on for 3-4 tanks of fuel. This is what I have always done with great attention. I am on my 6th engine now and it is holding up but won't develope enogh power.. thanx for all help but I think I am done with this whole deal.. Alan

Japanman

I think this may be your problem. The cylinder of the norvel engine needs to be hot to expand up to running size. If you break in your norvel too rich, the piston will be too tight at the top of the stroke, making it lockup. this means that everytime it goes through the top of the stroke the conrod is having to wrench it back down, causing huge stress to the conrod. This is why people here advocate running in your norvel after first heating it with a heatgun to get the cylinder temps up.
Now if you have run your norvel in too rich (I.E slobbery four stroke) and the rod has held together, the piston will be worn away and when you lean up for power, it won`t have any compression- this sounds to me like what is happening for you. I`d get a new cylinder and piston set and start again- and don`t run it in rich- run it in just on the rich side of what makes the best power.

I hope this helps you.

J.M

fiat

Thank you and I bet you are right, but I don't feel that it should be this hard to have fun and I have never had to break in an engine like this before.. Alan

AndyW

My Feedback: (1)

Fiat,

Sorry to hear of your troubles with the Norvel .074. If the rods are breaking, then the problem is that they are bending first, then the piston bangs against the crank web or backplate, or both, and then they break. Look at the rod. The stem is ridiculously thin. I've just made up a new rod for one of my .074s that bent just from running a large prop as a diesel. Seems that just the running loads bent the rod. The engine was well broken in and ran well on glow.

The reason the rods are bending is that the engines are EXTREMELY tight at TDC. Look at the last few threads on the discussion of proper break in of Norvels. Some varying opinions but all address the unique problems with breaking in Norvel Revlite engines. If you take a new Norvel Revlite and try to start it cold, while installed in the heli this is the problem. The engine is being brutally forced over at TDC when new and the thin rods are bending.

Yes, fun shouldn't be so much trouble. The thing is that Norvels have excellent warranty and service. All your bent, broken engines, (or at least the parts) should have been replaced for free.

flyinrog

My Feedback: (1)

1705493, they did, that is the heli company replaced 6 engines for him, but the last one locked up in flight and broke a few parts with the crash, and LMH wont replace the crash parts but they will replace the engine....fiat has had some major dealings with them,, I have one I'd like to break in on the bench but it is so freaking tight my LMH starter wont turn it, maybe if I get time I'll try the heat gun/hairdryer/torch method...Rog

AndyW

My Feedback: (1)

flyinrog,

Check the latest issue of Flying Models and the article by Dave Gierke, noted engine expert. In the article he recommends that ABC type engines be given the heat gun treatment during the first few break in runs. The Norvel Revlites are not ABC,,, but actually, the pinch at TDC is even worse, crying out all the more for the heat gun.