I am trying to design and build my own jet model because i think this is the fun of this hobby.
i would like to know what is an apropriate airfoil for a sport jet?
(I know nothing about airfoils but trying to learn).

It all depends on what you want your jet model to fly like.

Thin and almost symetrical for pure speed. There's some HN series airfoils (HN1033 for example) as well as some of Martin Hepperle's thinner pylon racing airfoils that would work well. Landings will be fast though unless you incorporate flaps or build very light.

If it's a jet look-a-like that you want to be able to fly through smooth fast maneuvers then a 10 to 12 percent thick symettrical airfoil would work well. The RAF 27 or RAF 30 would be good for this. These have a finer entry than the usual NACA stuff which should offer a better high speed range. Probably not as good at the low speed end than the NACA's but they are probably better at the high speed end. The 30 reminds me a lot of the airfoils that were used on the past generation of pattern models before the pattern went to a slower closer in style of flying.

Begin by setting a maximum landing speed and wing loading. If this results in a coeficient of lift that is less than about 1.0 then you can get away without flaps. If the coefficient of lift is greater than about 1.0 for the landing mode then you will need wing flaps. If you just want to do large, high speed maneuvers then a thin symmetrical airfoil will do very nicely. If you don't want to use flaps or a thick airfoil your ability to turn tightly at high speeds will be limited. Selecting an airfoil depends on what specific numbers you want to put on its performance envelope and how lightly you think you can build it. Airfoil selection like most design decisions depends directly or indirectly on everything else about the design and its purpose. The essence of design is to find the balance between conflicting objectives that best meets the mission requirements and priorities.

i would like to thank you guys for taking the time to answer to my quesition. I have allready designed the fuselage (Starting with the easy part first), it has a length of 1.8 m and the target weight will be around 8.5 kg including wings,retracts,engine,e.t.c.
I am aiming at a 1.7 span wing with zero incidence regarding the thrust line at a stab with a negative 1 degree. I am designing a system that will allow two separate designs of wings to be fitted to this model on to serve as a forgiving trainer wing and one as a high speed wing (both with the same incidence,but different sections ).Firstly i want to design the trainer wing.What i want from this wing is to allow low speed landings and low speed flights. What would be an apropriate airfoil/s?

A plane that weighs 8.5 kilograms will need a wing of much more than 1.7 meters span, assuming the wing has an aspect ratio of 5 or 6. Either the weight will have to be reduced by a factor of two or the span will have to be increased to about 2.4 meters with an aspect ratio of 5 or 6 in order to get the wing loading down to that of a trainer.

Yes it will weigh that much because all surfaces will be made from molds (fuse,wings,etc) but they will not be vacuum baged.If i increase the span what kind of section would you recomend?

I suggest the S8036 at the wing root transitioning to the S8037 at the wing tip. For the trainer wing, I would suggest that you keep the taper ratio above 0.7 to control tip stall tendencies and for generous wing area associated with the root chord and span.

thanks ollie. Thanks for your time.

Angelos, I'd strongly suggest that you practice with your construction methods to learn how to build lighter that that 8.5 Kg. Sure you can make the wing and the model bigger to get more wing area and control the loading but the engine you're planning on using will have a hard time providing the performance you're going to want out of a jet type model.

There's lot of tricks and techniques that will let you build lighter. The first of which is to design for FLIGHT loads rather than CRASHING loads. If the model flies well it's less likely that you'll crash and need the extra strength anyway. The only areas that should be over built are the high stress points for landing gears and the like.

Another trick is to lay up your glass wing and tail skins over glass sheets and use rolls of toilet paper or paper towel so absorb some of the extra resin. Once cured but still flexible from being "green" you can bend these sheets over foam cores easily and laminated them on with a very thin wipe of more resin.

Why not figure out what you think you need for structural details and come back with the list? I'm sure that a model of that size can be built to close to half to 2/3 of that weight.

Marty Snell of Evanston, WY has designed several jet models (turbine and electric DF) and could give some pointers. I have seen his work and it is amazing. I believe some of his stuff has gone into production. Two of his latest models were a really neat turbine sport jett and a twin electric DF business jett.

Jet not Jett. I have that Jett 60L FIRE I'm getting next on my mind........

Zoom Zoom Zooooooooooom!