Keane

Hi all

I am concidering to put an evolution 26 (or similar gas-engine) into my KMP/ESM Spitfire. I now fly it with a Saito 180, which gives a lot of power, but I am keen to try gas. Looking at the E 26 manual, it says that max power output is 3,8 horspowers, but i guess that is with an optimal exhaust arrangement (tuned pipe). In my Spitfire I think the best practical exhaust-system would be the wrap-around inverted muffler.

Are there anybody that could give me some information on what performance (RPM) I can expect from the engine with the wrap-around muffler with propellers in the range 16X8, 16X10 and 17X8?

Keane

soarrich

My Feedback: (98)

3.8hp is a bit optimistic, that would be equal to a 50cc making 7.6 hp, the best 50 cc make about 5.5 hp. I'd say you make 2.5 hp, but it will work great in your plane. From what I've seen a 26cc gasser equals a 1.8~2.10 nitro, but without the mess.

WCB

The ones I've seen put out about the same power as a Saito 150 if that helps. Sorry can't give RPM numbers.

fritzdecat

No matter what pipe you use the Evo 26 will not have the rocket power a Saito 180 will have. The 26 comes into its own when
it gets on the pipe so to speak and screams.

I have had both engines and at the end of the day I liked the Saito powerband much more

Note... I had the tuned pipe on the 26

Charley

My Feedback: (2)

I have a MVVS 26 - same engine - tried it in a H9 1/4 scale Cap 232. It flew the bird but didn't put out enough power to suit me. Flew lots better on the MVVS 35.

One thing to think about: the carb on those engines is awfully close to the prop drive washer. In a Spit, I'll bet the carb will be sticking out, presuming you mean to mount it inverted. I'd use an engine with a rear carb and a thin muffler.

CR

pe reivers

The plane needs a prop extension hub of about 1", quite easy and OK with MVVS. It puts the engine backwards and allows for a nearly fully concealed lay-out.
3.8 horses as advertised is real. For tractability, a two stroke never was quite the same as a 4-stroke. The faster throttle response of a 4-stroke makes the "feel" of the engine quite different. The 4-stroke does not need to clear it's lungs like a 2-stroke does. (crankcase fuel accumulation in nooks and crannys)

WCB

3.8 horse power? Not doubting you, as you have always seemed to know what you are talking about...but I am very skeptical about that one. Sorry

WCB

Charley

My Feedback: (2)

Who makes one for the MVVS 26?

CR

pe reivers

why?
ever ran one well tuned using the tuned pipe?

captinjohn

Every MVVS engine I have seen run was a powerhouse. Only see one that did not run good...but the guy that owned it, admits he does not know how to tune one! Capt,n

Keane

Thanks for all answers guys!

My conclusion so far is that the 26 won't give me the power of the 180. I will try to limit the use of power on my next flights to see if I'm comfortable with a little less power, but especially in case of emergencies (disrupted landings) the brute power of the 180 saved the day more than once

Most likely I'll have to live with the oil-mess, and the pleasure of trying a gas-powered engine will have to wait to another model. Some final thinking still have to be done before the final decision is made.

The Evolution 26 would fit right into the engine mount and I don't mind the carburettor or the top of the engine sticking out (yes, it is inverted).

If anybody out there have some numbers on RPM achieved with the setup mentioned in the first post of the thread, I would be very grateful!

Keane

pe reivers

Use a 17x10 prop. The other props do not load the engine enough.
Power much depends on muffler design. A slightly decent wrap-around should provide in excess of 7500 rpm, probably up to 8000. A pipe will get that prop up to 9000 rpm.

gr8taz nitro

My Feedback: (7)

I was running an 18x6 xoar and getting 8400 on the ground running 91 octane and 50:1 mobil 1 2t with the evolution wraparound pitts. I've since had to switch to a 18x6w apc because I broke my last xoar doing harrier landings in the wind. It's a shame when the wind drops on the last foot off the ground.

pe reivers

What rpm did you get with the 18x6W? I'm interested for prop comparison data.
using the 3266 tuned pipe, that same Xoar prop brings 8800 rpm (3.1 hp) 8400 is 2.7hp.