the 2stroke OS 55AX has 1.75HP and the 4stroke SAITO 82a has 1.5HP... will it be better to get 2stroke as it has more HP? or would the 4stroke be better having more torque? what would be best for 3D and prop hanging later when I am up to it?

4 stroke is better for "3D and prop hanging" and better throttle response. I am done buying 2 strokes (ok except maybe for a piped OS 140RX, but only if the price is right).

Even though there is less top-end power, there is SO much more torque. You can use a higher pitched prop to gain the speed. The high power of 2 strokes only comes at high RPM, so either you're hovering at high throttle settings or you're revving up your engine going into aerobatic maneuvers. Either way you're making a bunch of noise and giving up throttle response, accuracy, and making more noise with a 2 stroke.

I have a large-ish plane that I had a 120AX in, at 3.5HP. I switched to a YS 1.10 with only 2.5HP, but am getting WAY better aerobatic performance out of, due to the amount of torque. As soon as you hit the throttle, the power is there - immediately. I went from a 15x8 and a 16x8 on the 2 stroke to a 15x10 on the 4 stroke, and found that I needed much less throttle to fly the plane - making less noise, leaving more power in reserve for verticals, etc.

Just my experience and opinion.

very nice explanation... would have gone 4stroke even if you said 2stroke... cause just look at this beauty...

I got one!

dammit... thought I had something here, very nice man... I love it!

Mines a 100 though. Youll love the Saito!

I have a 65... liked it a lot... gonna sell it and add the rest for this one...

Why not opt for a four stroker that produces MORE than 1.75HP?

e.g a Saito 1.00 instead?

Saitos are great engine btw, my favorite four stroker...

But Laser Engines are good value because of the exchange rate, are easily the match of Saito's and have the valve gear at the back where it's less vulnerable in a prang.

I guess beauty is in the eye of the beholder!

Laser Engines look nice http://www.laserengines.com/ and the Laser 100 costs 235 Brit Pounds or $396 MSRP. Nice V-Twins too.

Never seen the Laser, is it an off shoot of the RCVs?? I liked the RCV but it's another of those engines that didn't take off very well in the states. Maybe it was the added break in time?? Does the Laser have a pump??

I'll Vote for the 82, here's mine
at work.


Bob

depends on what you are flying. i put a 4 stroke in a plane that likes some speed (yak 54), it just didnt work well, put a magnum 52 2 stroke in and boy did the yak come alive.
as for the torque argument, with a 13x4 on a os ax55 it will torque roll my plane faster than i have seen anything ever torque roll. (mojo.40)
yes the throttle response is better with a 4 stroke, and they sound cool. however they cost a lot, and dont save you any money in the fuel area. (most 4 strokes like 15%+ nitro, you can run a 2 stroke on 5% which is much cheaper than 15% and will last longer)

3d, 4 stroke is best, 2 stroke will work fine
pattern, either or
sports flyer, 2 are best, 4 will work fine
speed planes, 2 stroke
big, heavy planes that lumber aroung, 4 bangers.
thats my opinion

cause I wanna get the Extra 300SP and the largest recommended is 82...

You don't necessarily have to stick to the recomended range, that is just a suggestion.

It isn't like the 100 will tear apart your plane with all that extra power and it will slip right into that plane plus it will have a lot more uses down the road. A little extra power is a good thing.

dont overpower it. i made that mistake with my pheonix yak 54. i put a .91 4 stroke on it and with the weight of the spinner/prop/ect i added about 3/4 of a pound worth of extra weight (and th lead to balance it). the plane flew and has insane power, but if you slowed down, it flew horrible, it just wanted to fall out of the sky.
keep it light (smaller engine) and your plane will fly sooooo much better

Lasers have been around for absolutely ages in the UK. The proprietor, Niel Tidy, used to be a constant contributor to the modelling magazines with "build it yourself" articles for small diesels and the like. He then began producing 4 stroke engines in about 1986 with CNC machined parts, all from billet. The key feature of the Lasers were high performance due to the intake configuration and the ability to perform well with straight (non-nitro) fuel. Modern lasers use advanced cylinder lining techniques with some aesthetic changes to the machining. the intake and exhaust configurations are unusual and allow some re-orientation of the control link and needle directions.
I have one and it starts a dream (unlike my Enya that needs a starter). I prime by placing my finger over the carb and drawing fuel up by flicking the prop. I then apply a remote glow source and twist the spinner backwards against compression. The engine usually starts immediately, first time and burbles away very quietly. Pick-up is very rapid, I don't think a pump would assist at all and the power of the Laser 90 Mk 1 is excellent. I have run it off straight 20% castor, but I prefer 10% nitro with 18% Klotz Techniplate. After sales service is excellent with spares easily obtained direct from laser or carb spares from Irvine or Super Tigre.
Although Saito GK's look pretty, I think the Lasers are just as nice in a different way and are better looking and better performing than stock Saitos.
RCV engines are a completely different company. Their trick is to use a rotating cylinder liner as the intake and exhaust valve. (Hence Rotary Cylinder Valve). They have engines powering drone aircraft (Predator I think) because the engine is economical and less prone to failure because of the simplicity of the valve arrangement. One aspect of their performance is that the propellor turns at half the rate a conventional 4 stroke would for the same number of cylinder firings. This tends to make them suitable for larger props or multi-blades. the sound is different to a conventional 4 stroke. The in-line versions need a special starter adaptor. I haven't got one of the mor conventional lookig types, so I can't comment on how you start them.

I apologize for hi jacking the thread Switch.

This brought up a question in my mind...

If you are running a four stroke (ASP .71 Four Stroke engine) with 5% fuel - what would be the disadvantages of this?

for 3d YS are the best. Better throttle response and power than any other 4 or 2 cycle, except for a piped 2stroke engine. The only problem is that they drink a lot of expensive fuel. The .63 that I have runs like a champ.

I sure wish people would quit saying YS is a fuel hog, it is no different then any other four stroke and burns 15% just like OS and Saito. Mater of fact my YS 1.10s are better on fuel then my Saito 100s and about the same as my OS .91s. I even run 15% in the 1.40s. I have even tried as low as 5% and the only difference I noticed was the idle was a bit off and needed a tune up.

Switch,

A 4-stroke has a much wider power band than a 2 -stroke. All the "sensible" power from a 2-stroke is at the higher side of the RPM range.

thats good to know... now doubt about going for the 82a is the best option...

Is quite simple, to produce more power more fuel is needed. That´s a fact. And yes, maybe they run ok on 15% but they run a lot better on 20% and 30% becouse they where designed that way. Don´t get me wrong, I love YS engines (I have 3 of them), and in my experience, the higher cost of 20 and 30% fuel more than worth for the preformance you get.
Making comparisions is very subjective. I have the 63. on a profile, and it uses more fuel than 50sx that I had a few years ago in another profile. But the power and torque isn´t the same. I also switched, from my venus II, a 110(non s) for a piped 120ax, and the 120ax use less fuel becouse it can swing a bigger and faster prop.