Jacked69

Since I only fly my alpha in the winter im getting bored with the performance, what size motor can I go up too? It came with the evolution .46 which runs great and is very reliable but I want MORE POWER dammit LOL. Any suggestions? I dont want to get a expensive motor for this plane but would like to go larger but still stay at a reasonable price. Thanks fellas.

bingo field

You might be happy with a SuperTigre 45, or the next size up, 51 or 55, but the larger one would likely overpower the model. I put a Magnum 52 4stroke on one, and get about 20 - 25 minute flights on the stock fuel tank. It's not fast, but it is a trainer, and it flies very nicely with it. You can prop it down in diameter and up in pitch with the Evolution on it to try and get more speed, but you have 8 - 10 rubber bands holding the wing on, and it will make funny noises when you begin to approach the speed that will cause the wing to lift off the fuselage. (If you hear something that sounds like someone rapidly slapping an inflated paper bag, that's your sign to slow down, before the wing lifts off, on its' own). I turned one into a taildragger and took the dihedral out of the wing and use it as an "advanced sport trainer". It takes some severe abuse, but has done a lot for me even now. When the weather may be to crappy for most of my other planes, I use this one as a test to see whether it is flyable out.

http://www.rcuniverse.com/forum/m_21...dragger/tm.htm

This post is only 2 pages long, but there is some good stuff in it about converting a trike to a taildragger.

Jacked69

Thank you Bingo, I think I will go with the Super Tigre .45 as its only 100$ and will probably be a very large noticable difference in performance. I also have went through different sizes of props, I am using a 10x6 or 10x5. What size would give me the most top speed? like a 9 size and what pitch should I go with? What about a pylon racer prop? Any suggestions on props would be great, thank you Bingo. I will do that next make it a tail dragger.

carrellh

I do not know for sure, but I do not think replacing an Evolution 46 with a Super Tigre 45 will generate much of a performance difference.

The Super Tigre 51 ($84.99) is on backorder at Tower. You might find one on the shelf at a LHS.

Horizon claims the Evolution 46 will spin a 11x6 prop at 12,500. If true, I think the 10x5 and 10x6 you have been using are too small. A 10x8 or 10x9 would load the engine similar to a 11x6.

mclina

I need to break in my new .55AX, and I will probably do so on my Alpha 40.

I agree that the Super Tigre 45 probably won't be a big performance increase - but it sure will sound a lot faster . I have one on a Bel Air 40 bipe, and it is a very powerful engine. It just might not be the upgrade you a looking for.

I really liked the looks of that Alpha with the flat wing. I may try that some day.

And I never fly mine without at least 14 rubber bands.

Good luck

MinnFlyer

My Feedback: (4)

I also agree that a ST 45 won't be any better. I have an EVO 46 that spins an 11x7 at 11,500RPM. Just try switching to a better prop. That engine is plenty of power for that plane, you just have it propped wrong.

Jacked69

OK I will get an 11x6 and let you know what difference I see. Thanks for the input. I will just save the money for the engine going on the pulse 40 which I think will be a OS 46ax rather than the OS 55ax ABL because I read there is not that big of a difference but I may just spend the extra 25$ or so and get the 55 because if I go larger I wont have any regrets if the 46 wont cut it.

russm

os 55ax, there is a difference

beachbrada

My Feedback: (17)

That OS 46AX is a really reliable engine, Ive swapped it between 3 different planes and never had any problems starting or tuning. I currently have it on my Twist 40 with a 12x4 prop and I get about 12000 RPM's. When I had it on my Sig Four Star I was running a 11x6 and that plane flew really fast, a little too fast, I learned the hard way about over-stressing a plywood/balsa frame assembly. I snapped the right wing panel off after a high speed dive then a quick climb out. Needless to say I have learned throttle management and plane limitations from that situation. But I also agree with the other guys on trying different props, it makes a world of a difference. The higher the pitch the faster it will go, but the only down side on the higher pitch props is once you point that nose straight up dont expect a whole lot of climb out.

MinnFlyer

My Feedback: (4)

Ditto! Get the 55AX

carrellh

If I were buying a "40 size" two stroke engine (for the Pulse or other sport plane) it would be one of the bigger ones.

The cost is so close to a 46, and as long as you use the throttle as more than an on/off switch, I think having extra power available is a good thing and worth a few extra dollars.

dash008

My Feedback: (1)

I broke in my 46AX on my tower trainer. It would fly around nicely at about 1/4 throttle and take off like a rocket almost strait up! It was too much power for that plane really, I can't imagine what a 55AX would be like. But if I had one lying around, I sure would slap it on and find out!! I'd rip the wings off for sure!

Jacked69

Carelleh I agree with you, you can never have enough power but you dont always have to use it. Just knowing its there is reassuring incase you have to get out of a bad situation or just wanna do a low 100Mph flyby over someones car, JK LOL....I think I will just go with the 55ax abl. 30$ more and I wont have any regrets later down the road.

jib

Aviastar .53 from Sig. $79.99 + $8 shipping or through your LHS.

Jack

bigedmustafa

My Feedback: (2)

Jacked69, you might get a buddy with a tachometer to help you tune your Evolution .46 NT. Even with a 10x6 prop, that engine should have been able to make your Alpha .40 trainer scream at full throttle.

A good 11x6 propeller should make a big improvement, but only if the engine is dialed in properly. Make sure you're really getting the 11,500 to 12,000 or so RPMs at wide-open-throttle that you should be. No prop will run well if the engine isn't tuned correctly. You'll also want to make sure the engine is idling reliably down around 2400 to 2800 rpms. If the idle is above 3000 rpms with that 11x6 propeller, slowing down for landings will be an adventure.

jib's suggestion of the Aviastar .53 2-stroke available from http://www.sigmfg.com is a good example of a bargain engine that will haul around a .40-size sport plane with authority. Another good choice to look at is the JBA .56 2-stroke available from http://www.bj-model-engines.com/SKJBA.html or from http://www.kangkeusa.com The $79.99 JBA .56 has been tach'd side by side with O.S. Max .55 AX and turns almost identical rpms on the same propeller.

You can read about Ed Moorman's test results here: http://www.rcuniverse.com/forum/m_67...tm.htm#6762745

Ed Moorman is a big fan of the O.S. Max .55 AX, so his positive review of the JBA .56 is all the more interesting.

In any event, the right propeller and a really good tuning can be more effective than replacing an engine. Good luck!

bkdavy

My Feedback: (1)

Ditch the 10x5 prop and go with an 11x5. 11x6 is a little too much prop, and will drag the EVO down to far. I've flown an alpha with the evo and a 11x5 prop, and its a great performer for a trainer.

Brad

opjose

I've flown the Evolution .46 and the PTS engines using both 11x6 and 11x7 APC props.

The .46 has no problem handling the 11x6 and does well with the 11x7 as well.

The PTS is happier with the 11x6 though.

bingo field

One last thing from me, you will also be limited by airframe drag, until you overpower it too much. It's a trainer, you should have fun with it, learn how to make it do things you never would try with a different airframe. It is a "just relax and play with the sticks" kind of thing. It will never be truly fast, but you can still have fun with it.

downunder

It's almost impossible to overpower a model, even a trainer, if you do things right. By doing things right I mean keeping the CG in the correct place and choosing a prop (particularly the pitch) that doesn't allow any speed increase. My son has a 1.08 in his 40 trainer and it's a delight to fly.

rambler53

My Feedback: (494)

I hate to ask, but have you guys flown a Super Tigre .45,
and a Evo .46,
and a SIG .53?
I have. You'd be amazed how much free time in a day you have eliminating women from your life!
I didn't want to guess what outcome I'd get, so I enjoyed testing engines for years on my planes. I like trying engines with the fast clamp mount from Great Planes on my low wing planes. There are a lot of surprising results.

Each engine performs differently on prop, fuel, glow plug, and airplane it's bolted to. Trainers have drag, and the wing is mounted with 10-12 rubber bands. It's a flat bottom wing? It's designed with dihedral, and I wouldn't want to push the plane too hard in that configuration.

The SIG is utter garbage, one of the worst engines I've ever come across. It ran hot on everything. It was sent back and replaced, the carb is a joke, the tuning was nearly impossible to pull off the first time, and I've tuned hundreds of other engines over a few decades. It's make Tower Hobbies look like a Rossi, and Tower isn't high on my list either in quality and consistency. One is great, the next is a dog.

The Tigre in fact is much more powerful than the Evo, considerably lighter, and swings a bigger prop, on less nitro content fuel. My suggestion is dumping the Evo muffler, getting a header and pipe, or mousse can and wake it up that way, and since it's covered in fins, throw some more nitro content at it. Start using APC props. Evo mufflers are very restrictive. Most of my OS engines I use the GMS .47 ot Tower Hobbies Pro .46 muffler, $14, good increase in power for the money, it will also fit Magnum, Evo, ASP, and other OS clones.

There is no gain on a .51 Super Tigre over the .45. The trainer version of the Evo is toned down a lot from the NT, and the drive washer has that heavy balancer on it, I suppose to help idle.

Speculating one engine over another based upon displacement is not sound advice or practice to follow. Reading specs on a owners manual is even more misleading. I love reading the 61 FX HP is 1.9 at 16,000 rpm. You'll never hit 16k! My Rossi .45 hits it at 16,000 on the ground, and tunes just as well. It was made to run 16,000. Do you think you can hit 16000 on the ground with a .46 or .55 AX? How many flights do you think it's good for at that rpm?

Flying these engines really proved a surprise to many. I do not consider any OS AX of any displacement a 'fast' engine other than the .25FX, that truly is a screamer, and I assume the new .35 AX is, and the old .32 SX was. But in the .40 - .50 class and above, they really are just sport engines, which is fine for any trainer. It's a great tuning engine, all novices with limited tuning skills love them as they should. The carbs are great. But it's not a performance engine, relatively speaking. I generally fly the older Super Tigres from Italy, round billet head, they just run great for me. But for speed, Dub Jet, Nelson, Rossi, Webra, MVVS, HP, and other high performance engines really make OS just another sport engine.

Try 9X7 prop, 15% nitro fuel, replace the muffler with a Tower Hobbies Pro .46 muffler. You'll be surprised what a few changes will do to it. For $159 for an AX .55, I'll take the Rossi challenge any day.