wreckerbc1

HI ALL,
I am almost finished building my first plane,An lt40.I was planning on an OS 46 ax as everyone recommends.However for about half the price i can get an SK50a.It has almost same power as ax same weight and warranty does anyone know anything about SK engines.Nobody in my local club has one. thx ahead of time

fredscz

My Feedback: (47)

My flying buddy bought a SK50 a while back. It starts and runs good. If you do a search you may find the threads that tell about the SK engines being ported/tuned for large props and lower rpm not small props that scream. That would seem to make the SK's just right for your application in an LT-40. Only time will tell if they will hold up in the long term.
That said you would not go wrong with the OSAX. I have two in use and they are top quality and worth the price in my opinion. Another you should consider is the Thunder Tiger 46 Pro. The TT46PRO is a proven engine for about the same price as the SK's.
Fred

wreckerbc1

thx fred,
the only reserve i have about the tt is its lack of horsepower.1.4 as compared to 1.5 forsk and 1.65 for os.I dont know much about engines yet as i am just getting into it is this a lot of difference or is .1 or.2 diff nothing

pcinc

My Feedback: (29)

wreckerbc1,
I started this addicting hobby only 2 1/2 years ago. While learning I bought an LT-40 from a guy at our club. He had owned it for 2 years and it's what he learned on. This Kadet has been used by other club members to train folks interested in getting into flying. It's such a gentle flyer it makes learning easier. My LT -40 has a .46 Tower motor on it and it has been flawless now for over 4 years and countless flights and is still running strong. The beauty of this motor is you never have to tinker with it, just fuel it up and fly it. If you look on the spec page on Towers sight, it is listed at having 1.75 BHP at 16,000 RPM which is a little more than the SK and the OS.The best part is it's just under $80.00 and if your not in a hurry for it they put them on sale every now and then. Since having such good luck with this Tower .46, I have bought 2 others and put them in 40 size planes with the same great results. I now have 3 that run perfectly and produce tons of power for a 46 size motor. For me, you can't beat the performance or the price of these motors.
Good luck with your choice,
Peter

d_bodary

My Feedback: (85)

On my girlfriends LT-40 i use a thunder tiger GP42 which is rated at 1.1 horsepower. Same engine i used on my PT-40 that i learned to fly with.

That being said the horsepower ratings are way overated. if you check the rpm they are rated at you will never hit the rpm they rate them at unless you run a 9x4 proppeller or something like that. Both engines you have listed are more than enough power for an LT-40. Like the first post said OS quality is top notch I don't know how the SK engine will hold up. But considering a lot of trainers seem to get landed nose first might not be a bad idea to try the less expensive engine that way you can be the expert in how long it will last.

Now for a few of my opinions like them or not they are my opinions.
Myself i prefer a bushing engine to learn to fly with than a ball bearing engine. Don't have to worry about bearings anything like that. But i have known many many people that swear by the ball bearing engines to learn with. So to each their own. Good arguements for both sides. Of course i also try and get people to try Zinger 11x4 and 11x5 props to learn with also. Keeps the speed down. Yes you break more props that way. But you also don't have a big plastic prop that survives and leverages the firewall out either.

Dennis

XTOL

I would also recommend the TT46 Pro. Its a proven engine and
about the best value in a 46 there is.

I have 3 of them and they all perform superbly.

Mike Hammer

Charlie P.

I have an SK-50 engine and have not been pleased with it at all. It broke in well, and the first dozen flights went well, then it started to die when pulling up in loops. It has defied my attempts and our club engine collector/guru's attempts to tune it. About 30% of the flights it achieves konk out for deadsticks, and 20% of taxis result in no flight as it dies on revving up. Too rich on the ground, too lean in the air. I retired it in disgust after one season, but remember this is just my experience with one engine.

I much prefer my TT Pro-46 to it.

Love the S/K-50 airplane, though. That's what I had it in. Now that airframe has a ST G-51 and that's been better still.

RichD

I have a TT46pro on my lt-40, and with a 12.25x3.75 prop, it will hover, but with no pullout power, but irregaurdless, its a very good engine, one that I recommend highly.

jaka

Hi!

Why, Why on earth choose a .46 ball bearinged engine for a high winged trainer plane?? Puzzles me.
I have been into this thing called R/C flying since 1975, competing in pylonracing, scale, aircombat and you name it and been active learning new fliers get started for the last 30 years and believe me, a OS LA .40 or TT .42 plain bearinged engine is more suitable for a high winged trainer airplane.
Why ? Because it's deliver it's power in more gentle manner than the more powerful .40 -.46 ballbearinged engines.
Then people say : "You can always throttle down"...excuse me for laughing...but saying so reveals their lack of knowledge about how it is learning to fly and the hardship a novice is facing when he or she is taking the first steps in learning R/C flying , especially so if you are at senior age.

I have seen so many people comming out to the field , especially people over 50 with their new high winged trainers powered with .46 ballbearinged engines and noticed how they have had difficulties controlling their airplanes due to the high speed. When I have asked them why they have choosen a .46 engine they have all said that the hobby shop recommended it...


To have a OS LA.40 or TT.42 perform good on a trainer it's vital that you choose the best props you can. And the best props to use are 11x5 or 11x6 APC, RAM , Graupner Cam prop or Bolly of the same size. A 10x6 is not, I repeat not the prop to use if you intend to learn flying a high winged .40 trainer. At least not if you fly at sea level.

When you have learned the basics of flying then you can get that ball bearinged engine and learn more advanced maneuvers flying a low winged airplane.

Charlie P.

Thinking back. That TT Pro-46 (which I still have but with a Perry Carb) was on my RCM-40 trainer when I got back into R/C after years out. It has been on four different models in it's career.

A ball-bearinged .46 is a useful engine for many, many .40 sized choices as a new pilot progresses.

An OS .40 LA is good for . . . a .40 sized trainer.

Maybe you want to pull floats someday on that trainer? Nice to have a little extra punch to pull that added drag.

Almost every prop plane in WW2 had a method of adding 20% or so for those times when it was desireable; whether it was a wire that could be "popped" by forcing the throttle or by blowing water into the cylinders. There are times when a little extra "oompf" is very, very nice to have.

The .46 gives a .40 trainer lots of climb, so the fledgling will soon learn to throttle back for level flight. See; it encourages good throttle practices from early on.

Montague

I want to agree with the above post that the HP numbers for our model engines are basically marking hype. You can safely ignore them.

And LT-40 will fly well on just about anything. I've flown them with everything from an OS .40LA up to a .72 saito.

Yes, you can, and should, throttle back. I agree that going too fast is often a problem for new pilots. And LT-40 can float along at an amazing slow speed. It's important to teach students that throttle is another flight control, just like elevator, aileron, and elevator. It's not a "set and forget" thing. With a modern .46-.50 in the nose, the LT-40 can do level laps of the field at 1/4 throttle, easily. If you're really smooth, and you have the right prop, you can do it almost at idle.

Charlie, that SK engine problem sounds very much like the way the smaller Magnum engines that I own acted. It sounds like the engine developed an air leak, probably somewhere in the carb, like around the O-rings. I bet you could fix that engine with a little work with fuel tubing, RTV and maybe JBWeld.

mikenlapaz

Montague

What would you recommendation be for wreckerbc1 if he were to choose a TTPro 46 for his plane to fly at sealevel?

I purchased APC props ranging from 10-4 up thru 12- 5 for this engine to fly at sealevel.

Also got a TTPro36, should that BB engine be a consideration?

Montague

While you could fly an LT-40 on a TT 36, you'd spend a lot of time at higher throttle settings, and you wouldn't have much if any reserve power. It also limits the acrobatics and fun stuff you can do with an LT-40 later if you are that short on power. I'm not sure, but I'd expect the TT .36 to be about the same as an OS .40LA. But I haven't seen that engine in person, so I don't know if it's "hot" for it's size or what.

The LT-40 is a BIG plane for a .40 size trainer. With the .36, you'll be "on the wing", so you won't be able to do things like a sustained 45degree (or steaper) climb. You'll fly more scale-like. This isn't bad, just not the way many guys fly their models.

Given the choice, I'd go with the TT .46 over the .36. I have an Evolution .45 (that I bought used and abused from an ex-student who totalled his trainer after soloing and wanted to move to bigger planes anyway). I think I'm using an 11x5 APC prop, and I pulled the baffle from the muffler. The plane is also converted to a tail dragger, which is nice.

Fastsky

Nothing wrong with using a good 46 sized bearing engine on a trainer. The extra power is well worth a "lot" of times while training. On SK engines, I bought a 80 size to try because of the price. It has never run well enough to even do a high speed taxi, let alone attempt a take off. In this case you do get what you pay for!! I pulled the engine and replaced it with a Tower Hobbies 75 engine. ITs inexpensive as well but its the best engine in its size range even against OS or TT engines regardless of the higher price engines. [8D]

mikenlapaz

Igive, did a Google on SK RC engine and it drew a blank. Who sells them?

TigerTail

My Feedback: (2)

Look here [link]http://www.kangkeusa.com/[/link] or here [link]http://www.atsrcplanes.com/skengines.htm[/link] for SK Engines

Charlie P.

Since I put bad karma on one of their engines I'll come back and say I have one of their S/K-50 Fun Fly models and it is my favorite sport plane. I fly it year round (great on skis) and it is just one of those models that everything seems to come together on. I'd be hard pressed to say whether I prefer it or the original Das Ugly Stik. Broad speed envelope and, with 10% differential on the ailerons, will do linear rolls. And it looks good with the cowl and tapered wings.

Like Montague said, there is probably a fix to be done on this engine. I just had another (a SuperTigre .51) waiting and haven't gone back to diagnose the problem. Speaking of JB Weld, the throttle arm snapped off (four spot welds hold it to the barrel) and that was used to reattach it. Interesting thing is it popped off at 1/2 throttle and I had the longest flight of my life with that same model mentioned above waiting for the fuel to run out. She takes off at less than 1/2 throttle.

bruce88123

Charlie - that power setting was called "War Emergency". My dad flew P-38 photo recon out of England during WW-II and he said thatpower setting saved his life more than once. Total armament on a photo P-38 was a 45 sidearm that the pilot wore. Other than that he could take your picture. He said there was nothing like sitting between those 2 engines and shoving the throttles forward and hearing them scream into life. FAST!! Especially downhill. Photo recon planes also had NO escort planes. They were on their own.

Charlie P.

My hats off to him (and all photo recon pilots). Not only unarmed as photo scouts, but later overflying a kicked hornet's nest AFTER a bomb mission to check on damage. Can you imagine the recons over Penemunde where they had everything imaginable to throw up in your face. Whew!

And the ball turret gunners. Prime target, plus a hit to the hydraulics and you can't leave, and are road pizza on landing. Heck, ANYONE on a daylight raid in a 240 mph bomber facing 380 mph fighters w/ 20mm cannon and flak. Dry feet for six or eight hours, most of that without fighter escort in the early war. Over, and over, and over again . . .

They truly were a great generation, no question about it.

bruce88123

Small point but I believe a lot of the ball turrets were electric driven. Still had a lot of failures though because the systems got shot up.
http://freepages.military.rootsweb.c...all_turret.htm

bruce88123

OK Charlie, we're both right. Found this in the link I llisted.
Two post handles, pointing rearward above the sight worked valves in the self contained electro-hydraulic system to control the movement of the ball.

wreckerbc1

hI ALL
THANKS FOR YOUR RESPONCES.
I DECIDE TO BUY THE SK50.
LOTS OF REASONS PRICE A BIG ONE

bigtim

My Feedback: (13)

I think price is a poor reason for buying a particular engine, the difference between most engines is about 30$-50$ not that much $$ for reliability and performance.
you can get a OS46 for 100$ from tower with there discount A good price for a great engine that will out live most people.
settling for something you might regret buying because it was the deal of the day, your better off saving the extra couple of $$ and get the best quality there is.
there's such a small difference in the actual money spent VS. the quality of the item engine/radio/airplane.
I would rather do without somthing so that I could save some more cash and get the best rather than a fair quality item that may or may not give me the reliability that I want.
there is nothing worse than going to the field and toiling with a engine or plane and not flying for me.

ChuckW

The horsepower ratings are a guideline but they can be a little misleading. You'll notice that the advertised HP is at different RPM on different engines, usually at an RPM that it will never realistically turn. The true test is how much torque it makes and how many RPM's it will turn the prop being used. I have a Super Tigre GS-45 that has a lower advertised horespower rating than an OS .46-FX I used to own. The OS ran excellent but the Super Tigre turns the same prop at higher RPM and the plane performs better. Truth is, just about any good .40-.50 sized engine will work great on your LT-40. Just make sure it is broken in well and is tuned right. personally, I'm partial to the Super Tigres. I know some people think they are cheap but mine have always ran great. I've been impressed with the TT Pro .46 too. I have a tower .46 that I wasn't very happy with at all. Then a guy at our club suggested some 15% fuel, it suddenly became an awesome running engine.

wreckerbc1

OK I didn't buy the sk50 because its cheap .I did a lot of research and read a lot of forums and owner reviews .From this i determined that the os is good engine that has to rev to 16,000 to reach its peak hp.Thus turning a smaller prop.
the SK reaches peak hp at 12,500 and has torque than the 46 ax.This means the SK can turn a bigger prop and still be in its power band. The SK also had as good of results as the OS did. Approximately 82% positive for both