What is your opinion of a 6 pound low wing sport plane with a .48 size 4 stroke? How well do you think it will perform?
Thanks

For a scale plane may be marginal.
For an aerobatic, definitely insufficient power.
That engine is comparable to a 0.35 two-stroke.

depends on the plane(trainer or something like a cap or pulse)... but generally I fly my low wings with a bit more extra power... that will fly scale like I would imagine... the plane wont be very capable... just enough to fly it... my opinion...

If you propped it for enough thrust to fly the plane it wouldnt be very fast. A 6 lb plane is pretty heavy for a .48 FS. Iwould imagine that size engine would be at home on a 5 lb plane or less depending on your flying style.

6lb sport plane needs more power IMO

I would look at 65 size 2-strokes (65AX)

The real parameter you should be considering is the wing area. If you have 600 sq. inches of wing area, your airplane will most likely fly well. I don't do 4 strokes as I never really understood why a person would want a heaver engine that puts out less power than a 2 stroke that for the same displacement is at least 30% mor power, easier to operate. I did use one and OS 120 for a couple years. Far too timid and touchy for me. I have a couple now NIB, Saito 150 GH and a YS 1.40 something or other also NIB. had 'em fo 5 years or so.

Back to your question, generally the 4-stroker is heavier turns a bit more prop at less RPM and is more tempermental. However if such is your choice, and you have a 6# airplane that has 400 sq. inches, of wing and you ask that question, you won't have to worry about it very long. It will be gone to the Happy Flying Ground. On the other hand, if your model has 800 sq. inches at 6# you might have considerable fun with such a plane as long as you are not trying 3D.

As an example in this picture taken 6-7 years ago that big red high-winge with much dihedral is a replica of the GUFF, Dr. Walt Good's original RC airplane first to be flown in the USA. It operates on 3 channel (Dr Good only had a rudder that was L or R or Center. ) A Como (Sup. Tigre) 60 hauls it off the ground in 15 ft. I do loops and rolls A-OK. Cruises well at half throttle. Thermals well. I think - without going out and measuring the chord - the wing is 1200 sq. inches +/- with a 96" span and it weighs 9#.

Hope this gives you some background info. for modeling performance.

Depending on what you want the plane to do you could probably get away with a strong 46 two stroke.

I had a Sig Four-Star 40 with an OS FS-52S. The aeroplane is 5 lbs and 600 sq-in., and the engine is probably slightly more powerful than the 48. For "flying around", it was more than enough. For huge loops and vertical lines, it was not more than needed. The Four-Star weighs about a pound less than your plane, so I guess that it will fly ok, but it won't go very far when you point it straight up.

G'day

The Skyraider Mack 2 is the "hack of choice" at my club. It weighs in at about 5 pounds and has 556 square inches of wing. Most are powered by OS 46AX engines and they go like stink to the point of fluttering their elevators and ailerons. But, one bloke has one with an OS Surpass 48 like yours. It happily chugs around. It is not as fast as the two stroke powered models but it flies really well though without unlimited vertical performance.

The plane you are talking about is 6 pounds but if it has a larger wing area, then it could fly quite well with the 48 but just don't expect it to be really fast or to go up forever.

I also have a number of Sig Kadet Seniors. They have wings of 1150 square inches and I have successfully flown them with the older OS FS40 which is far less powerful than the 48 Surpass. Your 48 would fly one of them really well.

Once upon a time, many years ago, I had a 48 Surpass which I put in a Thunder Tiger ARF trainer. Everyone told me it would not fly well. They were wrong. And when they flew it, they were amazed. It was no rocket ship but it was steady and would do the things trainers are supposed to do and a few more besides.

It will fly your plane. It won't be a rocket.

And as for four strokes being difficult to use, I find them far easier than two strokes. My Saitos, Enyas and Laser four strokes are extremely easy to use and quiet and economical to boot.

Right on mike

Thanks for all the replys. The wing area is 627 sq. in. Iam not looking for a rocket or anything like that. I just want it to be a little areobatic, nothing special. At 6 pounds and with a 627 sq in wing I was hoping that it would be a decent fun flyer to play with and give me a slower plane with a little areobatic ability

G'day

From what you have described, I think it will be a nice combination with modest but pleasant performance.

Someone mentioned the Four Star 40. I have one with a Saito 62 but I have flown one with an OS Surpass 48 and a friend used to fly one with a very elderly Saito 40. These would be similar to what you are talking about. The Four Star with the Saito 40 (which was always flown without any nitro) was so aerobatic that it impressed me enough to build one. Since then I have built two more and also have the 60 and the 120 as well all because of that little Saito and the hot pink Four Star 40. I also have two of the more recent Saito FA-40a engines and have considered pulling the 62 out and putting one of the 40s in because it would end up lighter and adding lightness always works.

Enjoy.

Mike in Oz

Ienjoy seeing how small an engine Ican get away with on my planes. The GP Escapade is samewhat heavy .40 size ARF with a high wing loading but good manners and Ifly mine with a .36, It flies just fine, plenty fast enough for my relaxed flying style.
Irecently installed a Magnum 30 four stroke on my .25 size Sig Kadet Jr. It hauled it around great just not in much of a hurry, Ilike it.
Ithink Iwill try one of those new 4 star .20s with a Mag 30 in it.

G'day Jeffie.

I agree. Most models these days are overpowered. Like you, I sometimes like to fly a model with enough power and little more. I also do like the occasional overpowered model but only occasional.

My favourite two "underpowered" models were the Four Star 40 my friend owned with the Saito 40 and my ancient Kadet Senior. The little Saito 40 did a wonderful job of flying the Four Star 40 but this was helped by the fact that my friend deliberately build the model to be light. As a result, it would fly really slowly in close and was a very engaging model to fly and to watch.

My old Kadet Senior had had a long life when I put the OS FS 40 in it. The little FS 40 produced very little power but it did it in a very pleasant way. It was one of the sweetest engines I have ever run. To get the Kadet into the air required a long take off roll and very gentle application of the elevator to coax the model into the air. She would then very gently climb to flying height and at that point you could reduce the power to about half and putter around for ever. Loops were possible but required the technique used by real aeroplanes of the 1930s. Build up speed in level flight, then a gentle dive to coax a little more speed and then up and over for the loop. Much more fun than bang the throttle full open and apply full up.

Both these planes flew on their wings and not their props and I think this is what the OP was looking for. I will be interested to hear his results.

Having said all this, I also have a Big Stick with a Jett 46 in it. Just waiting for the right weather to test fly it. (It has been very windy here lately as well as very hot.) I don't think it will be underpowered.

Mike in Oz

Thanks for all the reply's. Iset up the engine on a test stand today and tried several prop combinations. Iam trying to decide on either a 10.7 or a 11.6 both seem to run up pretty good and idle well. I guess Iwill just have to try both in the air and see which will be better. Iam leaning to the 11.6 as I think it will haul the plane around a little better. By the way the plane is a Space Walker by Seagull. I would like it to behave in a scale like manner. Iam told that the full size plane kinda puttered around but was capable of areobatics. Will keep you informed.
Thanks again.</p>

Hi!
A heavy plane! It will land pretty fast!
Suitable props are not 10x7 or 11x6. For a .48 fourstroke 12x4,12x5, 11x7, 11,5x6 APC are more suitable.Best props these days are APC,RAM and Graupner "Cam-prop".

Not sure but I figured with this planes wing loading the plane would land pretty slow. Also looking at suggested props for this engine I came up with 10.7 or 11.6 someone correct me if Iam on the wrong page, thanks.

I would say to go with the 11X6 it should give you decent thrust and speed.