Hey guys, I have an alpha trainer I purchased about three months ago and just now have really gotten around to flying it. I took it out today and everything went just as planned. I just feel that It doesn't have the power it should have. It has all the rpm you could ever ask for....13,750 rpm. Engine runs and sounds great. What I have is a 10x4, two blade prop. Is this prop efficient enough for this plane? I have a 10x8 spare prop that I didn't think to change out (because I was having too much fun) But this 10x8 prop will catch more air right? I may have to just try to find out by just using the darn thing.

To get to my point.......regardless if the 10x8 prop fixes my problem, will a port job advance the performance of this engine? I feel I am pretty good with a dremel tool. I have ported about twenty RC car/monster truck engines and all with a positive effect of the work I proformed on the sleeve, and got about 865 HP out of a blown 427Ci big block Chevy engine that had my port job done to it.

All and all, I think I can do the port job successfully but will this help performance or will it just be a waste of my time?

Has anyone done this before?

THANKS FOR YOUR INPUT GUYS!!!! THIS A REALLY GREAT SITE TO BE ON!!!!!!!

P.S.....I would have posted this in the rc car engine board, but I thought this question may fit better here.


Joe

Hey Joe, It sounds like since you have done them before with cars and trucks you'd be safe to give it a try. Airplane motors aren't nearly as expensive as car / truck motors. Heck give a try...... let us know.

You know what? I think I will. I just found a used evo motor on ebay that has about 2 days left, 6 or 7 bids and up to 19 bucks so far. I may as well try to get that one if I have a boo-boo on my port job. I'll take pics too.......that is, if I get the time. It may not be real soon so I might start a new thread about it later on.

Later!!! THANKS!!!!

Joe

A good way to kill spare time, BUT an 11x6 APC will do more for power.

even a wood 11-6 would be better, and its cheaper

Have fun -- it's your $, however, schneurl-ported 2-strokes are not even remotely like car & truck engines. You just might get a bit more power, but much more likely you will screw up the timing (piston-ported 2-stroke timing is port-dependent -- both crankshaft & cyl ports).

Don't think that I am trying to discourage you -- I like to mess with motors myself (and I've wrecked a few doing so), but you are unlikely to gain anything at all, & will likely reduce the performance. It is generally more beneficial to do exhaust tuning mods & make carefull prop selection choices.

Your motor is seriously under-propped for its airframe application. With a 40 sized standard trainer airframe & a BB .46 engine, you should stay away from 10" props, regardless of pitch -- the disc area is too small for max efficiency. That is probably why you are unsatisfied with its performance -- an APC 11-5 or 11-6 will work wonders. If there is adequate ground clearance, a 12-4 is another good choice.

Just remember, this engine will output better the more fuel you run through it. From your post, I can't tell exactly how much you've run it, but it doesn't seem to be a whole lot. I have one from last November, have run about 5 gallons of fuel through it, and it runs better all the time. You can buy replacement parts for that motor fairly cheap if you do mess it up, however.

don't know how strick noise polution is where you fly.
have you tried removing the baffle from the muff ?
or installing a mac pipe?

as you know ..after porting engines they sumtimes become
finikie to tune or won't stay tune
porting engine for a land vechicle is onething

on an airship that you must compensate tuning for gain of
altitude...... i hope you mastered dead sticks or you'll become
the king of dead sticks soon..

The prop you are running is the reason you are not getting the power out of the engine. Ball bearing 46 engines should be running 11x5, 11x6, or 11x7 for general sport flying. For your trainer I suggest an 11x6 MAS (the black prop ). Once your landings are good switch to an 11x6 or 11x7 APC. The MAS are "more tolerant" of prop strikes than an APC, however, they are not as efficient. An 11x6 MAS is ABOUT as efficient as an 11x5 APC.

The porting MAY enhance the engine performance. You seem to have the experience, so it might be worth doing. 46 size engines are cheap when compared to a stock car engine (actually they are cheap even compared to a regular car engine ).

The fastest Alpha I've seen had an APC 10x7 prop and a big (3" I think) plastic spinner on it. The spinner really makes a differnece because it smooths out the airflow around the nose. And like other guys here have said, your prop is your biggest problem.

Porting the engine will only do so much with out a tuned exhaust, it probibly isn't worth it, but if you want to do it, go for it. Just be sure to get some tach readings useing more reasonable props before and after.

yeap....a bigger spinner or a nose job.
something to prevent the wind from hitting fire wall.
trainers have high drag to begin with anyhow.
i slapp in an o.s. .46 sf on a v mar trainner ..it didn't move.
but it floated n floated n, floated n floated

this 4* .60 flys great with only a .61 magnum

i clipped the wing 3"
took out diehedral
wheel pants
nose job
decent size spinner.
lighten it.

but is still had to experiment with props to match the engine's power
curve and airframe

pic of nose job

HEY LEFTNUT!!! That nickname is so kool man!! I never would have thunk it myself.

ANYWAY....Your nose job is awsome! I just might do that myself also. Do you mind if I copied your design?

I thought about it pretty much most of the day today and I really dont think that porting is what I want to do. At the begining, it was a thought, but after much more thought, I think that a port job may in fact boost performance levels but inturn, make my fuel econimy a whole lot worse. It did on my rc cars. On a stock engine (RC Cars) it would run for roughly 14-20 minutes. After the port job, It almost cut it in half, like 5-10 min. But overall the work kinda was worth it, lots and lots of power, higher rpms, and a couple of em ran a little cooler too. Don't know how but they did. I'm going to the LHS this afternoon and will pick up two or three different 11 inchers and maybe even a 12" prop to try out this weekend. I tried the removal of the baffle but I had lots of problems with it dying on me. THATS HOW I GOT SO GOOD AT DEADSTICKS!!! Put it back in and all my problems went away. Don't quite know what the problem was there.

Guys, thanks for the response. I will try and test out some bigger props and see what the outcome is and I'll be sure to post results.

BINGO FEILD.....I have a little less than a gallon thru the engine. (about three tanks left in a powermaster 10% gallon can)

THANKS AGAIN GUYS!!!!

Ill let ya know what happens by Sunday

LATER!!

The baffle creats backpressure to the hose going back to tank. On a climb, the engine starves for fuel if there's not enough pressure in the tank.

If removing the baffle caused running problems, you're probibly setting the engine too lean in the first place.

Be sure to back the engine down from peak RPM on the rich side. I don't know if cars do the same kind of thing, but airplane engines "unload" in flight and turn a higher rpm in the air. Add in the G-forces encountered that often have a tendancy to pull fuel away from the engine, and you get the engine leaning out in the air noticeably.