savagecommander

is that just a by-product of combustion or could that lead to piston damage eventually?

Hobbsy

My Feedback: (102)

SC, the carbon in a model Diesel engine is migratory and is constantly on the move, it flakes off goes out the exhaust and builds up a little more. Its never a problem.

gkamysz

My Feedback: (19)

The amount of buildup depends on many things, but the type of oil is important. Certain oils will cause more carbon than others. Normally it's not an issue. I find that significant build up can make it very hard to start if flooded. I think the carbon will soak in fuel and then it's hard to dry it.

savagecommander

ok. really close to trying my hand at diesel. tired of the plug/fuel/needle issues with nitro but i will have to wait untill the snow melts. so if 2 stroke diesel have more torque than nitro, and 4 stroke nitro have more than that, what is the 4 stroke "D" in terms of power? i would love to pull out my MT and have a huge sticker on the side that says "diesel powered"

gkamysz

My Feedback: (19)

My conversions make no more torque at normal RPM. I do seem to have more torque at lower RPM, below 8000. I haven't done any comparisons to glow at such low RPM because I haven't taken the time to adjust compression ratio. Power is about the same at the top. The huge improvement is in fuel consumption. And if you choose to go the etherless fuel route, consumption is even lower and fuel cheap. The etherless fuel is not fully proven.

savagecommander

etherless fuel? is it used because of its low flash point?(ether) i dont mean to hijack the thread but i gotta learn how i can

by the way, is that THE camp crystal lake?

gkamysz

My Feedback: (19)

Etherless fuel thread:

http://www.rcuniverse.com/forum/m_4561055/tm.htm

Re: camp Crystal Lake. Friends would ask me that question when I was in junior high

ddd

If you use store bought model diesel fuel and you adjust your engine right there is no big build up of carbon. If you make the mistake that many people that run diesels, run it rich and over compressed you will build carbon and if you build enough you could damage your engine when the space between the head and the piston is gone. For those that think they can make a better and cheaper diesel fuel remember this, the fuel is mostly oil so don't get carried away with adding too much lube to your formula.
A note of interest to some, we stumbled onto a modeler running one of our Super Tigre .90's on youtube.com to see it just type davis diesel.

Bob Davis

gkamysz

My Feedback: (19)

http://www.youtube.com/watch?v=LyvcFx6iFdk

This is a diesel conversion of an FS-26 I ran into on YouTube.

Motorboy

gkamysz..
You ran the engine????

I discovered and saw the text are at swedish as here: Hemmabyggd 4-takts diesel på OS och ASP delar ,translated to english: Homebuilded 4 stroke diesel at OS and ASP parts.

The engine owner are swedish man.

gkamysz

My Feedback: (19)

Sorry, I should have worded that a little more clearly. I found the video on YouTube.

Recycled Flyer

If that engine has a 'Lanova' cell on it could I please ask exactly how it works and get a working diagram of it?

I am not going to copy it , its just that I am intrigued by the whole thing!

Thanks.

P.S. Just found a diagram way back in post 6 and photos in post 32, interesting.

gkamysz

My Feedback: (19)

Very good work!

Evgeny, can you verify the prop size? 15x6 at 9350RPM is 1.2kW which is far more than expected (twice published figures on glow!). None of my diesel four stroke conversions have made significantly more power than glow. Maybe the prop is 13x6?

gkamysz

My Feedback: (19)

Now, this is truly curious. The OS FS-70 is virtually the same but 1mm larger in bore. I haven't tried converting the FS-70 yet. I wonder if the result will be similar.

I still have a very hard time understanding this power figure. The engine is making far more power than it should.

gkamysz

My Feedback: (19)

So you've increased the lift of the cam by reducing the base circle. The question that remains is if the follower now rides on the edge rather than the flat. I'm also getting to the point where I'll be able to modify cam profiles, maybe even make entirely new cam shafts. I have a completely new engine design I've been working on slowly that will eliminate the need for the lanova cell and use a conventional contrapiston. Yes of course, I reduce the carb throat as necessary. Such large throat is not needed with diesel or gasoline spark ignition.

Recycled Flyer

Why not copy the design?

Well Ihave no facilities to do so although I have friends that have.

And since my passion is for controline stunt where you are physically tied to the model, Imust be able hold that model in flight and here 15x6 at over 9000rpm would probably pull my arm out of its socket!

Ihave a personal caveat, do not go over 12" in prop diameter for any hand held model as it just isn't fun when the wind starts blowing due to massive line tension.

But Evgenie, you seemed so pleased with what you have created that it's becoming infectious - this is definetly one of those 'feel good' threads!

Cheers mate.

littlera

Everyone knows you can get a factory fresh 41 4C Diesel from Enya, right??

https://cs206.xbit.jp/~w041133/store...roducts_id=327

regards,

littlera

Mr Cox

It has a fixed compression...

bogbeagle

http://www.youtube.com/watch?v=dMBgtVSLqq0


You can see my conversion running, here.


It's a Saito .50 that had a damaged head ... so I knocked up a simple, new, head and "converted" the engine to diesel. Works pretty well. Modest power, but will fly a Wot 4.


Pig-ugly.

Motorboy

Привет Евгений-арм из Красноярск! Congratulations on the converted model 4 stroke engine!

But there are an extra tip in the contra piston, It can be glowing by combustion. Be careful with the length of the tip on the contra piston since this is loss of cooling effect in the tip via lanova camber. The results will be burned sealing on the contra piston.

I did with my first conversion of the OS FS 40 with the extra long tip to increase compression ratio, the results was burned O-ring. Then i removed the tip from the contra piston, the problem with burned O-ring was solvent.

I can russian language since i am married with the wife from Ukraine.

bogbeagle

You have made a lot of work and it causes respect for your work...
Saito it is heavy for conversion, and repair of the motor and manufacturing of a new head sew conversion much more difficult.
[/quote]



Yes, I wouldn't recommend making a new head ... it is much more sensible to convert an existing "good" head.

However, my Saito had a badly-stripped glow plug thread and also was of too low a compression-ratio to run as a diesel. There was no way to fix the glow-plug thread, so the original cylinder head was scrap.

I separated the head from the barrel and incorporated the barrel in the conversion ... along with the rockers and valves.

Really, the project was "just-to-see-whether-I-can-do-it". The only alternative was to scrap the engine.

ZachB10

My Feedback: (9)

Interesting thread.  Looking at converting one or more of my 4 strokes to diesel.  Anyone convert a OS .91 FS, or a YS 120?

Hobbsy

My Feedback: (102)

Zach, here is my Saito .80 turning a Bolly 13.5x8 at 8,792 on Davis ABC mix, I did nothing to the engine. The glow plug has no coil in it.

ZachB10

My Feedback: (9)

I have a Saito 80 GK as well.  Do you still use a glow ignitor to start it with no coil?

Hobbsy

My Feedback: (102)

No glow power, it fires right up using a starter. Today it is 19f it might not start so easy today. There are many glow engines that will run on Diesel unassisted. But you are stuck with one prop size.