Hi, I'm Richard and am trying to get back into RC flying.

I had flown heli's some years ago, left the hobby, but now want to give planes a try. I've ordered a Sig Kadet 40 to start as a trainer, but am having difficulty determining which engine to place in it. I'm leaning toward 4-strokes, but not sure which manufacturer (Saito. OS, YS) and what size. SIG recommends a .40-.46 (2-stroke) or .40-.54 (4-stroke). But the 4-stoke recommendation seems a bit small. I attempted a search here without much success. Any advice?

Thanks!

I'd stick with a 2-stroke they are so much cheaper and let's not forget this is a trainer. If you want a 4-stroke save it for your second + plane. If your heart is set on buying a 4-stroke for your trainer I'd go with a 65 or equivalent.

i would use ither 40 or 46 2 stroke.. os is not cheep any more. problyt go for abc 46 2 st.. but remember that the modern engines are more powerfull then 20 years ago. so you probly need a bigger prop then the run of the mill sizes any way your maual will tell you the recomended one

Welcome to RCU , glad you made it back to the world of RC
I have this plane, and have had a ST.40 , Evo .46 and a Magnum 4 stroke .52 in it . The 4 stroke is what I`ve stuck with and my second choice would be the ST.40
The 2 strokes work fine ,but do not have the same pulling power as the 4 stroke. The plane just handles better . No need for speed , it`s a trainer.
For a 2 stroke , the O.S .46 is the easiest motor I`ve ever dealt with., but if you are confident with your tuning skills , don`t be afraid of the lower end engines . Once broke in and tuned they run just as will as an O.S and most have more power.
I make this recommendation based on fact , not personal preference . Let the beatings began.

A .52 4-stroke should fly similarly to a .40 ball-bearing 2-stroke while a .70 4-stroke should fly similarly to a .46 ~ .52 2-stroke. A 4-stroke engine will be quieter than a 2-stroke, provide better fuel economy, and spit a bit less oil on your airframe than a 2-stroke.

YS's smallest 4-stroke, the YS .63, is a supercharged model that puts out far more power than your Kadet would ever want. I would rule this engine out for your trainer. Saito and O.S. both make very good 4-strokes in a .56-size, but they're breath-takingly priced at $249.99 and $194.99 respectively. The Saito .56 is actually not wildly overpriced, but there are some good lower-cost alternatives.

The Thunder Tiger F54-s is available for $179.99 from http://www.thundertiger4u.com, http://www.infinitehobbies.com, or http://www.ehobbies.com. You can get free shipping from the first two resellers, however, so that gives the TT F54-s about a $25 price advantage over the Saito after shipping. This is a very high-quality engine at a pretty reasonable price.

The Magnum XL .52 RFS is a .52 4-stroke available from http://www.hobbypeople.net or from http://www.towerhobbies.com for $129.99. At this price, the Magnum .52 RFS is barely more than an O.S. Max .46 AX. While Magnum Engines haven't always enjoyed the solid reputation that they now have, this particularl 4-stroke model is rated at a very solid 4 out of 5 stars here on the RC Universe User Reviews section, with only one reviewer giving the model a particularly bad rating:

http://www.rcuniverse.com/product_gu...?engine_id=171

Any ringed engine will require a more thorough breaking in than an ABC-type 2-stroke. I believe that the Magnum .52 RFS, if properly broken in, will prove to be an excellent match for your Sig Kadet. At $129.99, it's also one of the best 4-stroke values on the market.

If you're just not sure about Magnum or Thunder Tiger, then I'd recommend you spend the extra required for piece-of-mind and buy the Saito .56.

Good luck and good shopping!

I did a lot of research regarding the LT-40 and ideal size engines. I had seen a few with 4 strokes but don't recommend them for beginners. Cost is the primary reason - they cost up to 3x as much as a comparable 2 stroke.

I chose the Thunder Tiger .46 Pro. It's a good performing engine you can get for around $80-90 bucks. ABC construction and ball bearing supported crankshaft. It weighs a bit more than an LA .40 or LA .46 but this helped me as the kit-built LT-40 tends to be a bit tail heavy. Mine balanced perfectly with the TT .46 Pro. While it doesn't overpower the model, it gives a bit of instant thrust to get quickly out of a potentially bad situation.

If I had to do it again I'd go the same route again. Perhaps that's why I bought 2 of them.

This is not meant as an attack on you, or your skills tuning and your many years of experience in this hobby.
Just a question as to what type of Dyno you used to do a comparison test of the lower end engines VS OS.
and do you have copies of the test results.

Tho I have run a dyno and a engine test cell for a major airline , I must admit , I have never dyno a rc enine.
What I have done is try different engines on the same airframes as I had stated in my first post. A good way to tell the difference is to use a scale and measure the lbs and oz. of pull each engine puts out on the scale . Put the scale between the airframe and the plane hold down. Try different engines , using the same prop and used this to make my observations. This is also a good way to see which prop pulls the hardest.
I call this a poor mans dyno. and how I came up with my findings . Sorry , I did not record these finding, but then again , I never thought I would have to defend myself over something so insignificant . Sorry if I offended you.
Give it a try , you might find it works pretty good. Or do you have a better way ? If so , please share it with us.

WOW!

Everyone,

Thanks for all the advice and assistance. There is a lot of good information here!

I'm partial to 4-strokes (I'm an energy engineer, and like the energy efficiency and engineering involved). That, and the high pitched whine of two-strokes kinda' irritate me--or was that just the sound of heli's?) LOL.

Anyway, I expect that the engine I use here will eventually find itself into another bird, so I'm not shy about investing a bit more up front with that in mind. However, the power/cost/weight ratios given by the 2-strokes can't be beat and it takes a lot of fuel to pay for the difference in cost vs. efficiency. There's a lot to think about. But the field is much more narrow than it was. I like the 4-stroke OS .56, but they are a bit too proud of that one! LOL.

Now for the second plane....hmmmm-----hahahaha (I can tell I'm about to get addicted again!)

THANKS AGAIN EVERYONE!!!

Well, Insanemoondoggie did say to "Let the beatings began (sp)."

The good news is, overbored77, that you don't need to use a dyno to measure the relative "power" of an RC airplane engine. RC airplane engines are designed to do one thing and one thing only, they're designed to spin a propeller. A propeller is designed to push (or pull) air, and the faster a propeller is spun, the more air it moves.

You can compare the relative power output of two similar engines simply by running them with the same glow plug, the same fuel, and having them spin the same propeller. The one that spins the propeller the fastest is the most powerful. A Glo Bee tachometer from Tower Hobbies costs $24.99 and will allow you to make accurate comparisons between different brands of engines. There are plenty of folks in the Glow Engines forums who do this all the time and then post their results:

http://www.rcuniverse.com/forum/forumid_173/tt.htm

There are certainly other considerations when choosing an engine such as warranty coverage and quality of service, availability of spare parts, fuel requirements, ease of tuning, ease of break-in, aestethic qualities, and expected longevity just to name a few.

Insanemoondoggie's assertion that many less expensive engines will out-turn a comparable O.S. Max engine can be confirmed easily enough simply by viewing the Tachometer Readings forum to which I provided the above link. Still, the question isn't so simply as dividing peak RPMs by the selling price of the engine. O.S. Engines are highly prized for their many fine qualities even if they don't turn a prop any faster than a GMS or Super Tigre engine of the same displacement.

As for the original poster, I hope I gave RBachman some food for thought. I think he'll enjoy flying his Kadet with a 4-stroke on the nose and he doesn't have to spend a small fortune to do so. Let us know what you decide on, won't you?