D Bronk

I think, My Wise Choice, is to hold off ,on Converting Any engines ,and, eventually Get, The PB engine from Peter.The Warranty is second to none ..I would like to see ,more video, on that engine ,in flight though..

peterburford

Efish,
You'll not regret the Enya. Like I said, they know their stuff.

Dave,
You'd be a welcome customer.
But don't ignore the other larger diesels out there.

Peter

combatpigg

My Feedback: (3)

Don't forget the other issue, diesel planes and iron on covering. diesel attacks the seams and will make it harder to keep an ironed on finish looking nice. the solution then seems to be to go with a painted model. I don't know of any way to make a painted model come out as light as a film covered model, unless you go with silkspan, but even then, you need a fairly hefty build up of paint to really seal the tissue, and tissue is so easy to puncture. I suppose if you are a very fastidious flyer, and are willing to do a complete cleaning after each and every flight, the models' finish will stand a better chance of holding up. My diesel planes all look much older than they actually are.

AndyW

My Feedback: (1)

Dave,

For some reason, RCU isn't informing me when a new post occurs on some threads so I missed the latest on this one. Send an email directly to my email address and we'll talk.

I agree that generally, glows are built to run as glow and lots can happen when you convert them to diesel. I HAVE had some cranks break. Well, I have also JUST yesterday broke two,, and both were on my hot Brodak engine,, the one that does 19.9K on a 6 x 3 on my Low Stik. I swapped in some neoprene lines on the tank and gave it a go. Stupid me, instead of using the next prop up,, a 7 X 3, I went with an 8 X 4 just to test the max prop this engine will pull and how it compared to glow.

All went well and I adjusted it and got a real nice growl. Then BANG. Yup, the crank broke. Okaaaay, I won't do THAT again. I was really anxious to run my hot runner on diesel and after a rebuild I tried again. This time though, I decided to do an experiment to see how a diesel would perform using a glow sized prop. Without thinking, I didn't back off the compression screw and when she lit off, holy chit, did it wail. But by the time I fished out my tach,,,, BANG,,, again. DAMMM, I shouldn't have done that either. Note that this engine hauled that 6 X 3 on glow for many, many runs with no problem. The break was not where you'd expect. I had enlarged the intake port to a "TD" style and this, you'd think would be the weak spot. Not so.

Well, the one crank broke off at the crank pin along with a bit of the crank web. The other broke off the entire web, nearly cleanly. But neither broke at the port.

I've rebuilt the engine and thankfully, no harm done as she does what she does on glow,, just fine.

Lesson learned. Listen to the guys who have done it longer and have WAY more experience. Still, I've never broken a Norvel crank. Bent a few rods,,, but,,,, not since I learned better how to start them.

Efish,

You're welcome, I'm no expert by any means, its just that, I guess, I'm a lot closer to the learning curve.

What I like about the conversions is that well, yes, maybe they ARE built a little too light. But that's why I like them. They ARE light, have throttles and mufflers and you can run them as glow to get them broke in and to find the needle settings. Hell, all you can do is have the fun of trying it. It may surprise you. And when you're done with the conversions and have your appetite whet for more, you can get an engine that can take it, and then some.

About coverings, I agree with combat except that I have not had a problem with Monokote. Some of the other "Kotes" do melt under the influence of diesel. Best to test first.

peterburford

Andy,

You're having fun!
Don't let any of my know-all comments slow you down.
You know how it is -- those who know it can't be done, don't, those who don't know just go out and do it.

But in time I shall add some of my Father's and my experience to my site to explain our reasons.

Peter

AndyW

My Feedback: (1)

Not a prob, Peter, honestly. You're right, I just dive in and see what happens. If not for being dragged into diesels, kicking and screaming, I would have missed out on a lot of very gratifying experiences. I have friends and relations who look at me funny from time to time when I gush about some new thing I'm trying. They just don't understand the fascination and love of small machinery that we have. Too bad for them.

D Bronk

Wow!!![X(] I`ve just seen ,your Crank pics Now ,Andy.They look like they Shattered, like, Cheap glass,in Hot Water..And 2 of them in one Day[].I`m not sure ,if that`s my idea, of a Fun test session.I suppose it`s worth it, if you can learn something from it..Seeing that makes me Wonder, if, the Con-Rod.,could get stretched too?After all, it`s not that beefy of a part....I have Chev V8 302 C.I. aluminum Rods, and, High compression pistons,they can get stretched, at a much lower RPM,than what these Norvels put out.I know the Chev stuff ,is pushing, and pulling, a lot more mass,BUT,I still wonder. Have You ever considered, or, checked that out?..Those Cranks, appear to be a ,Cast ,and then Machined part.Wonder if a forged one wouldn`t be better,maybe even a Billet machined part from Superior Shaft...But then ,you`re on your way, to a scratch Built engine.

That kind of makes me want to learn the basic principles, of Diesel Running ,with the PB engine,even more....Peter ,you`re engines ,Don`t fly apart like that,Do they??That would be a warranty item,wouldn`t it..

AndyW

My Feedback: (1)

Dave,

I'm not surprised your Chevy blows rods,,, me, I'm a Toyota man,, never, ever blew a rod. [X(] And stretched? Dunno how you stretch a rod,, all loads are in compression, aren't they??? In any case, the Brodak, Norvel and Wasp rods are machined directly from bar stock.

It's important to note that these cranks are from the Brodak/CS engine. I have NEVER blown a Norvel crank. I bent a few rods in the early days on the .074 and maybe an .061 and I did make much beefier rods as shown below. This occurred when I primed into the exhaust with no muffler attached. I did this because all the instructions say to. Hell, I've bent rods when whacking the engine on glow,, when I was in a hurry, overprimed and it was starting to drizzle. You know, you finally make it out for a coupla flights before dark and you're determined not to waste the effort of getting to the field.

All of these things happened over a period of time. In the case of the .074, I found that the very early ones had a rod stem the same diameter as their .06. So a longer rod, much stronger engine with a bigger prop and the same stem as the .06,,,,, bad idea. To see one of these early skinnies would make you shudder. They were clearly WAY too light for the task.

I've come to believe that some of the old paradigms of dealing with diesel engines evolved out of the idiosyncrasies of early style designs with more primitive materials, fits and finishes. But even then, I've got a PAW .06 that starts nicely, by hand while priming into the exhaust. But then, it ALSO starts instantly by priming into the intake and hitting it with the starter. I've also got a small Frog and a small Merlin that are a real b*tch to start, by hand. You flip, get whacked, flip some more, get whacked, do it again, get a prime run, do it all again, and again and suddenly, they start. Neither will start by priming into the intake and hitting it with the starter. Seems like they're turning over too fast,,, or something.

I don't have extensive experience with diesel engines over many, many years with a multitude of engine types, sizes, designs and brands. I've read articles by highly respected diesel experts about difficult starting, sometimes, even for them. About how in frustration, they too would bring out the electric starter and give it a go only to bend a rod, snap a pin etc, etc. Much talk about loss of ether and difficult starting. Much talk about adding ether if your fuel goes sour. I always mix never more than 32 ounces and this gets used up in a month or so. It's in a metal can so no ether loss through any plastic. And with 40% ether, losing a little does no harm. And even then, I made a small mix with only 5% ether and the .40 started, no real problem. Throttling became an issue, no doubt from the need to squeeze up the combustion a little more. This may have caused a main needle setting that took the mixture required for the low speed out of a range that the low speed screw could provide.

Having said all THAT, there IS no guarantee that you won't break something. It is very likely that a purpose built diesel will never break as long as you follow the manufacturers instructions. And having said that, I had a great deal of trouble starting even proper diesels till I mixed up a batch of fuel with a LOT of ether.

The BIG problem I see is that most traditional diesels were designed to run WFO. Throttles are added as an afterthought and heaven forbid you should put on a muffler. My experience with throttling over these many years is that engine design has as much to do with the ABILITY of an engine to throttle as does throttle design. AND, fancy, two needle throttles are NOT required if the engine is designed right. Only a simple, ADJUSTABLE airbleed throttle is required. I marvel at the thinking that on the one hand, you're given a complex, two needle throttle and then, on the other hand, you get a throttle with a fixed or even no airbleed at all. It's either all or nothing and I sure don't understand how that thinking works.

A case in point about engine design is the AME .06 which has three bypass ports. You get more power but poor throttling is the result. Take the very same engine and swap in a Big Mig (five port) cylinder and throttling improves dramatically. Either engine though, benefits from an adjustable airbleed.

The old Mills diesels, for me, were the easiest to start. These are long stroke designs so that when you flip, your piston is going faster than otherwise and compression seal is improved and that's a good thing with diesel. The Norvels, on the other hand, have a lot of taper in the cylinder. No doubt the engineers had a reason and you can't argue with success. But this allows for some blow by and with diesel that can hurt when trying to start them. But we have electric, (or spring) starters and this overcomes the problem. As you saw with the Brodak, it lit off immediately and kept running. This was a stone cold engine with just a few drops of prime into the intake.

The quickest, simplest way to TRY diesel operation would be to get one of the RJL heads for one of your .06s. Follow procedure and you'll have success. The big caution though, is that I DO have a homemade starter that stalls if anything locks up. That's pictured below. There are 1/2A starters around that would likely be OK too but I haven't tried them. The other thing that would make diesel starting way safer would be to use a spring starter on your Norvel. As shown on my .074 below,,, and of course, illustrated with the video clip.

But,,,, there IS something unique to traditional diesel designs. A certain jenesaisquois that conversions don't quite match. My PAW, with no muffler, seems a lot quieter than my Norvel WITH muffler. An old Mills slugging an impossible large prop is a sight to behold. AND with the addition of a proper throttle you can get even them ticking over at an amazingly low RPM.

D Bronk

..I see you`ve got some points to ponder here.

;;I'm not surprised your Chevy blows rods,,, me, I'm a Toyota man,, never, ever blew a rod. And stretched? Dunno how you stretch a rod,, all loads are in compression, aren't they???

These are Exotic Aluminum ,Custom Drag Race parts .BME Rods, and ,Keith Black ,forged and Machined pistons.Yes they`re under compression untill you over-Rev and the crank start s to pull the Rods, and ,Piston around,instead of the other way Around..And at Bottom stroke Too,just prior,to ,the assembly changing directions..No surprise, that the Toyotas, never Blow anything ,they make next to nothing ,for Horsepower.LOL..

Wayne C

As friend of mine once said, The secret of a long lasting engine is to build one that doesn't have enough power to blow itsef up. For example, consider mid 70s big block pontiacs with less than 200 horspower and less than 9 to 1 compression. Some of them were running as solid at 125,000 miles as they were at 10,000.

Tim Wiltse-RCU

Andy,

When a real Chevy 302 is pushing a real 69' Z-28 around the race course it's aloud to break once in a while

D.

What in gods name are you dragging a Chevy 302 for?

LAter,
Tim

eroc144

My Feedback: (1)

Well you "stinky" guys have inspired me, and I just ordered an RJL head, some Diesel fuel, and the "special fuel line" from Texas Timers. I'm going to try the "conversion" on one of my Norvels or my AP Wasp. So expect lots of questions in the near future...

EG

AndyW

My Feedback: (1)

Dave, Tim, Wayne,

I've got a 90 Corolla wagon,,, 'magine that 302 stuffed under the bonnet. 'Magine sitting at the lights next to some dude's Camaro or something. Likely been done. Seen a video of a little Fiat taking on a Porsche. I guess the axles were beefed up just a little. [:@]

Eroc144,

Do the Norvel, just to be safe.

D Bronk

"D.

What in gods name are you dragging a Chevy 302 for? "

For the Same reason, G.M. Offered a, 302, 350,or 427,in the same Chassis.Because ,it`s "ALL GOOD",and it, "COULD"Don`t worry ,I never jeapordized, a Factory Block.I used 350 C.I. (4.00" I think )bored blocks,and 283 cranks.Had to cut the block for clearance, for the rods to Rotate.The Aluminum rods are Real FAT..

D Bronk

The Corolla would need, some under carriage stiffinig ,so it wouldn`t snap in half,from dangling, the front wheels in the air.[X(] .Power to weight ,would make it a Street KING,if you can find Traction..

Tim Wiltse-RCU

I have often thought of gonig one of those Chevy conversions into a 280Z. There is a couple of them running around town. Only problem is that there is not much room for my 1/2a airplane stuff[]

Later,
Tim

D Bronk

Put a car topper on it..LOL

gcb

There once was a man from Boston...

George

efish

My Feedback: (5)

Wow, lots of good detailed info here.

Thanks CP - I had overlooked the issue of covering durability with Diesel. Read about the special fuel tanks and lines required, but forgot that the fuel might go after the covering too. Think that would be a special problem with 1/2A engines since they leak so much!

Did'nt quite realise there was so much difference in the design and construction of a diesel engine. Guess the various posts detailing the damage done thorough overcompression should be a strong caveat against a frivolous conversion.

Well, now that we've come this far, I was just wondering which were the favourite planes to bolt a 1/2A diesel engine onto - any suggestions?

SGC

efish,
The biggest mistake beginner diesel users make is overprimeing/flooding the motor, diesels wont start(without practice and experiance) when over primed or flooded , this is when you are also in danger of bending/breakeing something - 2 reasons for not overprimeing.
Most traditional diesels start best when a drop of fuel is placed against the piston through a closed exhaust port- the small amount of fuel that wicks past and into the cylinder is all they need , later experiance will tell you how much or little in the intake will give instant starts.

Andy,
Your DC Merlin, is it in good/new condition ? if so read above, mine really doesnt like to be overprimed, they have good crancase compression and if I wind mine over slowely I can hear the woosh as the transfer ports open, cold start is choke till the fuel hits the needle valve, one drop against the piston and flick- 2-3 flicks and its away, hot starts are just refill, one drop against the piston and 1-2 flicks
My Barbini 1cc procedure is choke till fuel at the needle then still chokeing 3-4 turns more, then flick 3-4 flicks cold and its away, 1-2 flicks then for the rest of the day. The Taipan 1.5cc I learnt on didnt like venturie prime at all, just a drop against the piston or it would kick and bite , as a 10yo i had many bandaids on my fingers till i learnt what not to do.
Stewart

Big Al-RCU

Who drove a Baby Austin,

D Bronk

And Everywhere,he`d go,

His 1/2A Diesel plane, was Tossed in..

But when the Little Austin, Kept on Bust`in,

It really got, his Goat-us,so, He bought,

a Hot-Rod Lotus.



.That`s got to be, the Cleanest limerick ever,aside from the Diesel.

AndyW

My Feedback: (1)

Stewart,

Not even sure what the engine is, in the pic in my previous post but it's one that bites, and bites hard. Yes, I do prime the way you describe. The condition it's in is due to its being as old as it is in the hands of a local who gave it to me a few years ago. He bought it as a kid,, some 40 years ago. It still has very good compression, despite the wrench marks all over it. His excuse,,, hey I was a kid, didn't know any better. At least this one has slots for a wrench ala Cox. I have a couple more that have no visible means of screwing on or off the cylinder. What were they thinking? How'd they do it?

BTW, thanks for the crank, I'll be shooting off something useful you're gonna like. Send me a PM with address.

Big Al-RCU

Come on Dave, that has got to be the worst limerick ever and it's not even a real limerick[&o]
The diesel is the cleanest part.

Anyone over 70 should know the rest of it. The next two lines were:

There once was a man from Boston...
Who drove a Baby Austin.
There was room for his *****
And a gallon of gas
B .............................!

Al

D Bronk

Don`t know the rest ,of that one, but I`ll guess.


There once was a man from Boston...
Who drove a Baby Austin.
There was room for his *****
And a gallon of gas
B .............................!


But his Head,
was Blowen.


Better?....Dave