earlwb

Some people a while back stated that the Evolution 10cc engine and the NGH 9cc engine used the same carb. Actually the carbs are completely different from each other. There are quite a few differences in how the different designers tackled the problem of a RC carb for a small gasoline engine.

The Evolution carb uses a spray bar that encloses the low speed needle. The NGH carb uses an open needle spray bar design.
The Evo carb does not have a spray bar depth adjustment screw on it like the NGH carb has.
The Evo carb has a fuel inlet fitting that appears to feed fuel directly to the high speed needle, whereas the NGH carb fuel inlet fitting is on the front side of the carb and indirectly feeds fuel to the high speed needle.
Of course the Evo carb isn't using a fuel pump but has a small fuel regulator on it. The NGH carb uses a external regulator/fuel pump unit.
There are other differences, such as the four screw front cover on the Evo carb versus the six screw front cover on the NGH carb. I am sure there are other more subtle differences as well.

Ernie Misner

Nice pics! It's hard to tell, am I seeing a butterfly or rotating barrel in those for throttle control?

robc57

Look like barrels to me.
Do know if the UK shipments have left yet, specifically to Kings Lynn Models?

flyinwalenda

My Feedback: (5)

They are both barrel type carbs. The NGH requires an external pump placed/located correctly for it to operate . Appears the EVO 10 has solved the carb issues using just tank pressure.

AA5BY

Time will tell how installation variances affect fuel issues. My installation is inverted and will place the barrel somewhat below tank center line. We'll see.... eh.

earlwb

They are both barrel throttle carburetors. Walbro actually makes barrel throttle carbs too. Walbro had been making them for small gas engines for quite a few years now. The Walbro barrel carbs are seen on the small four stroke trimmer and leaf blower engines. Saito has been using barrel throttle carbs for quite a while as well, on their smaller four stroke gasser engines.

AJsToyz

Looks more like NGH tride to copy and improve on the Magnum carb and didn't do so well.

earlwb

Some more comparisons of the Evolution 10cc and NGH 9cc engines.


Weight of Evolution 10cc engine by itself:


Weight of the NGH 9cc engine by itself


All up weight of the Evo 10cc engine with muffler and ignition unit


All up weight of the NGH 9cc engine with pump/regulator, ignition and OEM muffler


To make it more equal, using the Evolution muffler with the NGH 9cc engine all up weight


Pictures of the two engines side by side

earlwb

Comparing the two different CDI modules used with the Evolution 10cc and NGH 9cc engines.
Both are made by RCexl too.  But the Evolution  version can handle higher voltages such as from two cell LiPo or LiFe battery packs whereas the NGH version is limited to 6.0v maximum.  The Evolution CDI is slightly longer but it is more narrow though.

earlwb

The Magnum engines are made by the same company that makes the Evolution engines as well as others like ASP, etc.
NGH on the other hand is a different company that came up with a different way of doing the same thing.

AJsToyz

Just stating a simple fact, the Magnum was at the shows two years ago and the NGH looks very similar. I don't live in China so I really don't know who has access to see what.

earlwb

Actually the Magnum prototype engine's carb was the design used in the Evolution engine. NGH did not copy it.
I think the Evolution people took over the development to sell and market the engines instead under their brand label and not the Magnum label.

Magnum Prototype .52 gasser in a test plane picture from a couple of years ago.

AJsToyz

OooK.

Kmot

My Feedback: (24)

Is that from when they were testing it at the Apollo field?

Mikola

kochj

It is a valid concern. In nitro cars, if you ran the engine out when it was winter, the cyl never comes up to proper temps.
This causes 2 things: The engine will loose compression. You will only be able to run the engine in cold weather, as this is the only way it wl develope compression,.
Metal expands and contracts....
It brings up the question, how do the other ringless motors handle freezing weather?

RiverLarry

Kochj I have read yor Post and ( what are you trying to say ) ???? R/L

earlwb

Mikola, yes NGH had gone down a similar development path that Evolution did. But NGH decided to use a external pump/regulator unit. Evolution seems to have solved the problem with their carb though. The two carb designs are somewhat similar but the actual carbs are quite different from each other. Different carb bodies and everything.

Warbirdguy

Being in the marine engine business for 30 plus years, I can answer that one. The old (pre 1958 outboard engine) used a crank case pressurized fuel system. The steel tank was sealed and pressure from the crank case pressurized the fuel tank. It took away the need for a fuel pump. But, what was overlooked was there were two lines going to the tank. A pressure line and a fuel line. Now, if the fuel line ever got damaged or came loose from the tank or engine, it would spray fuel everywhere creating a worse case scenario with fuel vapors and raw fuel all over the place and looking for something to ignite it, like a running engine. Or, you’re setting in a boat with a fully pressurized 3 or 6 gallon tank of gas. Not something I would want to be near.

Now, apply this to this aircraft engine. You run a regular glow type carb with a pressure line pressurizing the tank to eliminate the fuel pump carb. Two issues. One is the above mentioned. Second is when the engine stops and you still have gas in the tank, chances are its going to bypass the needle valve and run out of the carb into your airplane. May not be alot, but, unlike glow fuel, gas is explosive even in its smallest quantities. Either one not worth the risk.

I do agree that the current pumped carb is way too heavy for a small engine like this.

So maybe another answer to this issue would be the standard glow carb and a small bolt on fuel pump like the old "Perry Pump" of years gone by

WBG

airborneSGT

My Feedback: (15)

Has anyone just flown the engine a lot to see how it will perform. I promise when I get one to fly it like I stole it. Same way I fly big planes :-) I dont take it easy on any plane.

Ernie Misner

I think the barrel type carbs offer a more linear throttle response as compared to the butterfly type walbros. Is there nothing in the manual about how far away you can place the tank?

vertical grimmace

My Feedback: (1)

The engine has not been available for any length of time yet. Maybe a week or so? Patience grasshopper! The knowledge you seek will come in time.

AA5BY

Tank Location

Because muffler pressure is used to provide the pressurization to the fuel regulating and metering carburetor, the tank still needs to be mounted in line with the carburetor, and as close to the rear of the engine as possible. Care taken in mounting the tank as described will provide trouble free operations in all flight attitudes.

rhd-RCU

My Feedback: (36)

If the ABC engine doesn't get up to the correct temp. It will wear out prematurely.

daytonarc

My Feedback: (5)

The outboard engines I believe had a sealed fuel system. This uses exhaust pressure. as soon as the engine stops running the pressure will blead off through the muffler.