I have a friend looking at gettin the OTG 18.5 model however he wants to eventually try smoking a turkey on it. I told him beware it may not be possible but I really havent looked that size over very well. I have done many turkey breasts on my 22.5 model but not sure bout the smaller size one....anyone tried it?

I'm not totally certain re the fit. However, on Amazon the 22 1/2 is only 20 bucks more.

I have an 18.5 OTS and I did manage to cook a small turkey on it, but if he wants to cook larger ones then I would recommend the 22.5 OTG.
I have cooked several birds that were 15 lbs. on it without any problems.

It can be done with small birds 12-14 lb range but I'd be more worried about the lack of space away from the hot coals. Maybe Garry can add some more insight on how he did it. Seems you would have to move the bird around quite often to avoid getting it over cooked where the charcoal is so close to the bird. If you bank the coals on the outside edge of the kettle, and then place the turkey with the sides towards the coals, then you'll need to turn the bird, to keep the legs and wings from burning that are exposed to the lit charcoal. When you turn you'll want the neck and tail exposed to the lit coals. Then maybe flip the bird and repeat the turn process It can be done no doubt but, you can't just set it up and forget it like you could on a 22.5" kettle, but maybe you can. Now that I think about it, you could stand it up upright on the charcoal grate and bank the coals all away around the bird. Garry?????????

I don't think you would have the head space to do it on the cooking grate, but you can set it on the charcoal grate. It is possible to just ring it with charcoal around the outside edge.

However, the 22" is so much more versatile, if there is any way possible I would get that. There are many things you can do on the larger grill that are difficult or impossible on the 18". If money is a limiting factor, then search craigslist for your area and pick up a used grill. I see them often for $20-$25.

Having both the 22.5 and the 18 I really can't see how you can easily do a turkey on an 18. The proximity to the coals would make it very labor intensive. Plus every time you open the lid you lose the stable cooking enviroment and by the time it would settle back in you would have to open it again. If possible have him get the 22 since it is more versatile with the size of meat being cooked or the size of crowd being cooked for.