AMB

Ok you 1/2 folks Just picked up a norvel 074, ran a short time on glow runs well . A.J. Coholic made a diesel head for me
the engine seems to have not quite enough compression to fire off as a diesel. How much time do I need to get a good seal to get the compression up to get it running as a diesel my 061s runs great with either the davis or RJL head I fly these at the local elctric field and
with the low noise no problems martin

dieFluggeister

Hey Dan,
Sorry about nobody posting an answer to your question yet. We're not trying to ignore you but I don't know if anyone knows a solution. My experience is that the Norvels come so darn tight there is no problem with compression out of the box. I don't know a lot about diesels though - any diesel guys out there?

AMB

It was super tight at the top but seems normal now I was just flipping it a good snap just holding it with a prime and it fired off
will bench and hook up to a tank in a day or two looks like it will light offm from my previous start ups if it does this it will run.
DDD 1/2 A fuel
Its electric starter time ouch on the hand flips )at least no blood)

Dan Vincent

Martin,

I recently picked up a Norvel .074 too. Got any pictures of your diesel version.

ajcoholic

My Feedback: (10)

Dan,
I took a stock 074 head button, bored it out and made the separate contra assembly fit in like the stock glow button. I didnt have time to mess with cutting the threads, etc so it seemed the easiest way to get a head to Martin asap.

AJC

AMB

here it is AJ did a super job contra really a super fit , nice and tight (brilliant idea he did have to mess around cutting all those fine threads)

Dan Vincent

Andrew,

Great idea, simple is good.

Martin,

Keep us posted on how it runs. Did you get any numbers on glo fuel?

Those Squeaky tight pistons open up quickly when they get to operating temps.

Wonder if the Norvel crank and rod will stand up to diesel stresses.

AndyW

My Feedback: (1)

Dan,

I've had my Norvel .074 dieselized for several years now and did it similar to AJ's. Andrew has a better idea though with the locking bar. My first contra piston was very tight (by way of the O-ring) and needed nothing to hold it in place. However, as the ring wore in (or out) the contra tended to drift. So, I installed a heavy spring and that seemed to cure the problem. Till lately. I'll be adding the locking lever soon.

Regarding performance. This depends greatly on the prop. See the thread at http://wwwrcuinverse.com/forum/m_247..._2/key_/tm.htm

As you'll see, the 8 X 4 Cox grey did best on the ground (at 12K) and in the air. The APC was the worst.

My fuel is home brew, 40x40x20x2. The oil was Sig castor.

Martin (DieselDan) had consulted me privately with his starting problems and my advice was to use a 1/2A starter with the caution that the stock rod was going to be in jeopardy if he wasn't careful. In the end, Martin got his going by hand. Mine would start by hand occasionally but only if it was gummed up with lots of oil and only on the first start of the day.

The trick is to find the compression setting with no fuel in the tank. Then, only two or three drops of prime into the intake is sufficient to fire off the engine with a starter. Quite often the .074 will start with no prime required. I just fill the tank and apply the starter. After 10 to 15 seconds, enough fumes are drawn up the fuel line to fire off the engine, and it keeps running.

As a matter of course, for my dieselized Norvels and BECAUSE I use a starter, and ONLY because, I routinely make up a beefier rod. Also pictured and posted earlier are my first ideas as to dieselizing the .074. Concerned that the crank was going to break, I installed a Cox .09 crank. Power was way down and this turned out to be a failed experiment. Note the rod. This was overkill and the rods, lately, have been trimmed down a bit.

However, I've been running the same stock crank for nearly three years with many, many tanks of fuel through it and that crank just keeps on taking a licking. And it hasn't been babied, it's been whacked with a starter many times.

Also pictured is a dieselized Norvel .061 done up in a similar fashion. My first attempts at dieselizing Norvels were with the original AAN engines and what it took was a mixing and matching of components to get a super tight fit at TDC. This was then VERY carefully run in on glow. As a diesel, all it took was two to three drops of prime and it would fire off, by hand, after two or three tries. NO adjustment was needed to be made to the contra piston to start. What would happen was that each prime run would bring the cylinder up to near proper temperature until at one point, it would keep running with a neat, burrp, burrp sound. Then it would smooth out into a solid run. At the time, I happened to use a Wasp crank for the experiment and eventually the crank broke when I went to an 8 X 4 prop, just to see what would happen. I concluded that an 8 X 4 was just way too much load and never did it again. Till recently that is. I've run the Norvel .061 with all its proper pieces, including the crank and had a good full tank run with nary a blip on the crank. So far. For some reason, on the 8 X 4 prop, some days it'll run, some days it won't. I've got a video clip I can send you if you're interested. RPM was 8K plus on that day on my mix. It was surging a bit, don't know why, still working on it.

The upshot of all of that is that the Norvel cranks are TOUGH. Not to worry about them when dieselized. Norvel got it EXACTLY right in this area and I, for one, am grateful.

Just for the interest of all, there's another way to avoid having to cut metric threads when dieselizing a Norvel. This involves making a complete new head. The entire head is simply bolted in place with much longer screws. Pictured is the one I did for my Norvel .15. Like the smaller ones, the Norvel .15 dieselizes just great. Starts easily with a starter without having to touch the compression. Again, this is with my 40/40 mix. Lots of ether really helps.

For anyone interested, I've got a 15 minute video of the starting procedure I use and some flying of my sport design. This was taken last year. I've also got one flying off of skis using the ski design I published in Flying Models a few years ago. Dieselized Norvels are just incredible. With the starter, no problems starting in the winter, again, without ever having to touch the compression screw. It's always very close for starting and only the occasional tweaking is needed to suit the weather of the day.

The beauty of a dieselized Norvel is that you can break it in as glow and even find the needle setting on glow fuel. It'll be very close to that required as a diesel. Saves a LOT of hassle and wear and tear on the engine AND you.

Finally, it must be said that just as with glow, the dieselized Norvel .074 throttles virtually perfectly, right out of the box. As in the glow version, it must be kept in mind that the high speed needle has a broad range and is actually used to dial in the low speed. Keep tweaking in the high speed needle (at idle) till it holds on advancement and no more, and that'll be about perfect. I generally do additional tweaking while test flying.

AMB

Well today we got the 074 bench run.The only semi-suitable prop I had around was a 7x4 wood zinger> The engine turned 11900 on it.
The compression is much improved and a quick touch with the little Sullivan half A starter lights it off. I used Cluttons Old English mix just to use it up, DDD 1/2 fuel was used also. We have a total now of a half hour on it as diesel.The super tight "catch" at the top of DC
is gone. My many thanks to Andy W for his advice and AJC for a great head. Its going into the Decathalon electric conversion to replace
the 061 norvel conversion. The plane had to be hand launched, this should now get it off the grass.
martin
Dan Vincent, sorry but I did not write down the glow numbers

AndyW

My Feedback: (1)

Martin,

Glad to help. I promised you a Cox 8 X 4 grey. Still need your address. PM me.

My Cox grey did 12K and was superior, in the air, to all others.

Dan Vincent

On those tight engines.

They need to get hot (by running) quickly to open up to proper tolerances. If you turn them over cold they will never expand properly and you'll be scuffing off metal that should still be there.

The early ABC engines all had that squeaky fit at the top and a lot of good engines were ruined by guys who wanted them to feel like the older steel liners.

My advice: Fire them up and let them break in on their own.

Andy, nice post on your diesel conversion.

AndyW

My Feedback: (1)

Thanks Dan,

The Norvel Diesel .074 IS one helluvan engine. Uderappreciated and unloved. The weight of a PAW .049 with twice the power, and perfect throttling to boot. If only a commercial head was available.

And yes, fire them up but use a heat gun first.

JasonRP

Andy,

What kinda plane is the blue and yellow one in your pic above?

AndyW

My Feedback: (1)

Jason,

That's my own design, but it originally started out as a scaled down Headmaster. Flew the pants off it for several years till I smacked it real good and blew up the wing. So, I made a new, lighter wing with a much thicker airfoil. Flew the pants off of THAT till I smacked IT. That wiped out the fuse. So, I made a new fuse and built a larger tail. The fin/rudder was enlarged twice till I had what I wanted. The firewall was drilled for two styles of mounts in three different angles. The intention was as a test bed for various engines. I'll send a copy of the video when I return your engine.

Dan Vincent

Andy,

A heat gun is a great idea.

Oh boy, I can just see myself standing in the back yard on a 90+ degree day (I live in Florida) with a heat gun to warm up my engine. This time the neighbors will be shaking their heads for sure.

I recently picked up one of those Norvel RC .074's and it is a neat-looking little beast. Haven't run it yet so I can't go on about performance.

A while back I was thinking about getting either a Norvel or Thunder Tiger .07 but I like the compact muffler attachment method on the Norvel. The TT looks like it has a lot of extra metal to mount the muffler.

flyinrog

My Feedback: (1)

WHAAAAAAAAAAAAATTTT!!!!!!!!!!!!!!!!!!!!!! there's an engine that Dan Vincent doesnt HAVE?????

and its a TT .07,,,and you havent run a Norvel .074??..I dont really get the diesel-izing engines,,the norvel is a great engine,,smooth, quiet, powerful, starts like a light switch,,great throttle transition.(on glow)...I have a TT .07 but havent run it yet......Rog

Dan Vincent

Rog,

There are a lot of engines I don't have...running out of places to put them. I also collect Diecast cars..talk about using up space...and N-scale trains.

One of these days I'm gonna have to start selling stuff on E-Bay.

I've seen a lot of positive comments on the Thunder Tiger .07 on "Smallnet" so I can assume it's a pretty good engine. There seems to be more support here for the Norvel .074.

I'm betting they are both nice little engines. Like I said the TT seems to have a lot more metal in the muffler and mounting flanges which makes me think of unnecessary weight. Just looking at the two engine designs, the Norvel seems to be of lighter construction. Does anyone know the weight of these two engines. Whoops I have a diet scale....the Norvel weighs avout 3.4 Oz .... if the scale is accurate.

I'd like to see a head conversion for a standard glo plug but make the bottom of the plug hole "Blind" so the combustion chamber is smooth.

Diesel conversions provide more torque on a larger prop but RPMs will usually drop off when compared to glo. Diesel guys get a certain satisfaction out of understanding and running them.
Over the years I've seen a lot of guys tear their hair out trying to run diesels, so It's sort of an elite brotherhood of guys who can live with the diesel characteristics.

I like diesels but you have to make sure your exhaust is routed away from the model or you end up with an oily mess. They do run quieter than a glo engine and are usually more fuel efficient. I would recommend newcomers to stick with the glo engines and then learn diesels later on if they like to tinker.

AndyW

My Feedback: (1)

Dan,

According to the specs I have, the Norvel .074 weighs 2.66 ounces and the TT .07 comes in at 3.7, both with muffler. But it's in the area of performance that the Norvel shines.

I've never owned the TT but according to an article in RCM&E, it'll only do about 16 to 17K on a 6 X 3 prop, depending on brand. Not much better than a Norvel .061 at twice the weight.

I've dabbled with head buttons to take stock plugs on the Norvel both in the .061 and the .074 sizes. They work well and in some cases allow for better throttling on the .06. But, the tradeoff, as in Cox engines, is that you give up enough power to make you go back to the stock plug. At least I did. Besides, Norvel plugs are well made and do last.

If you like, though, I can loan you the buttons to play with. You just might find/have a plug that doesn't rob too much power. And if there's a button that works well for you, you can keep it. I can always make more.

I suspect that once carefully broken in, you'll be amazed and delighted with the Norvel. And if you venture to dieselize it, all it takes is a stab with the starter and its off and running.

Rog,

Diesels CAN be maddening, frustrating, impossible, mysterious, troublesome, b*tchy and all around a pain in the arse, as the Brits would say. BUT, a dieselized Norvel is something else. It behaves no different from the glow version except that is has a nice masculine roar. And on a larger prop, with lower rpms, much less irritating to the folks walking around the park. I've flown the same plane, on the same afternoon, switching back and forth between glow and diesel and there's just something very appealing about the way that big lumber pulls it along.


And yeah, they stink and are oily but that oiliness is just extra protection for your engine. And, it doesn't have to be that oily. My mix only uses 20% oil and has run one Norvel for several years with nary a hiccup. The rod is the only weak link but even there, you can bend or break a rod on glow if you're not careful.

I'm rebuilding my .06 version and with a new piston and cylinder, I'm hoping to tame it. I still have that Balsa Prods. Tiger Moth and an .06 lugging an 8 X 4 would be scale in size, rpm and sound. And, not that much heavier than a Cox Texaco.

AMB

Had a few minutes today and reran the norvel 074 AJs head starts easy running around 10500 top flight 8x4, idle good around 5k
good response no bogs on going to full throttle As far as the TT 07 goes I am told not a lot of power runs ok, Davis does not think
it would make a good conversion due to glow preformance, the TT10 is a whole different story little powerhouse, the idle on the 74 is not good with the 7x4. Andy you are on the money the 074 is getting better with each run and being very careful with the stock rod
and you are also right on the diesel set up 1/2 turn on the compression and ditto for the needle is the difference between running great or like crap the newbies would have some problems before they learned martin

Dan Vincent

Andy,

I may take you up on that plug converter sometime down the road. Right now I'm going nuts fixing up the house for some relatives coming in late July.

Have you ever tried making a "Blind" plug adapter so the glo-plug bottoms out against the bottom of the adapter? It would sure keep the combustion chamber clean. All the piston would see is a hole for the element. Just a thought.

Martin, those OS, Magnum and Thunder Tiger .10's will probably all take the OS .10 diesel conversion heads. I'd like to see if it also works on an ASP .12.

AMB

Dan the ASP 12 should make a good diesel. You will have to call Bob Davis to see if it will or he may be able to modify the head 10) so it does (great idea sounds like a good base engine) I have ASP 4 strks 30,52, 91 all great engines and mucho less $$ than OS
martin

AMB

Just re-ran and tried a zinger 7.5x4 10,500 2 head shims managed to reduce compression slightly to get contra just inside bevel edge
of head insert with my infra red temp gauge it is reading 250 at junction on head and cylinder, seems a little too warm? If compression
backed off we get the diesel miss, It could be ether% may needed to be increased slighty to lower compression and heat. Fuel Clutton
old english mix martin

AMB

Just re-ran and tried a zinger 7.5x4 10,500 2 head shims managed to reduce compression slightly to get contra just inside bevel edge
of head insert with my infra red temp gauge it is reading 250 at junction on head and cylinder, seems a little too warm? If compression
backed off we get the diesel miss, It could be ether% may needed to be increased slighty to lower compression and heat. Fuel Clutton
old english mix. It is rock steady and holds rpm martin

Dan Vincent

Martin,

I need to dig out my OS .10 and the ASP .12 to see if the heads will interchange. Being a .12 the ASP may have a slightly larger hole to fill. I like the idea that the ASP has a ball-bearing crank.

Hey, maybe Norvel will make an .09 or .10.....that should be a winner from the get-go.

Just stopped by a hobby shop in Sanford, Fl and picked up a quart of Norvel NVX 25% nitro fuel.
They also had a DU-BRO Norvel Aluminum Spinner prop nut for starter cone. It's about 3/4" dia.

Don't know how soon I can get to firing this baby up....too many irons in the fire.

Tried to find a Cox 7" X 4" but the hobby shop didn't have any. I have some Taipan, Top-Flite, Power-Props, Master, Zinger and a few others in 7"X 4" so I'll take some readings after it's broken in a bit. I have a feeling the Cox Prop is what I want.

I like this chunky little bugger, can't wait to run it.

flyinrog

My Feedback: (1)

Dan the .074 is supposed to be the power of a .10 in a .07 size ,,I guess thats why they go from .074 to .15 with nothing in between...Rog,,,I have a .15 I've never run either..