I just purchase a Goldberg Protégé kit to get back into flying. It has been 20 years since I last flew. My first plane was a Sig Kadet Mk II, which crashed (after many flights) in the hands of an instructor. It was either radio interference, or something came loose. I then built and taught myself to fly on a Butterfly and graduated to an Ugly Stick. I then grew up and didn't have the time or money to keep it up.

Now that I'm on my second career and have more of both, I got that RC itch again. I wanted something large that would be more than a basic trainer and after reading about this plane, feel comfortable with my choice. I want to be able to teach my wife and kids to fly on this and still be able to have a little fun.

The plane calls for up to an .80 four stroke. I can't seem to find an .80 size engine, and have already picked out my next plane, so I'm looking at the OS FS-91 II. Are there any areas that should be beefed up because I plan to use this engine size? Should I be looking at a different engine? 20 years ago, OS made a really nice engine.

One thing I always hated was the oil getting all over the plane. With this engine (or any other), can the exhaust be kept away from the wing? Will rotating the engine help? Change the muffler? Anything?

I see that the ARF version has a 2-piece wing, but the kit directions available on http://www.carlgoldbergproducts.com/protege.htm show only a 1 piece. I've built gliders with 2 piece wings. Because the Protégé has much more power, I was wondering if anyone else has done this and if they could give me the details.

I own a Saito 82 (4 stroke). I bought mine thru Donalds Hobbies out of Texas. No sales tax, no freight and it was discounted.

The engine worried me at first however now that it's broken in I have become quite fond of it. So much so that I have also bought a Saito 56 and 125.

I don't see how you can escape the oil issue. My 82 is mounted upright in a Senior Telemaster. I have the muffler aimed away from the fuselage and down but there's always a little oily sheen on parts of the plane (not much though). If you watch that exhaust stream coming from the engine it's amazing there isn't a whole lot of clean up to do after a flight.

That OS 90 Is a good choice , you don't have to run the eng full steam. and it will be a good eng. for many other planes.


Jacqie .......Brotherhood #27

Don,

Thanks for your reply and your engine alternative. I'll have to take a look at the Saito 82, but I'd still like advice on the OS. As far as the oil, I'm glad to see that yours is only a little oily. What I remember from the 2 cycle planes I have flown is that the right wing and right side of the fuselage was always heavily covered with oil.

You can mount the engine anyway you like and by deflecting the muffler you can keep most of the engine snot off the plane but never get away from all of it. Just the nature of the beast.
I have the OS 91 on my 60 size Kaos and it's A very good engine. All of my OS four strokes have been great. I just had to replace the muffler on mine this week. Be warned, OS is very proud of there parts and it shows on there prices!!!!! [&:]

Thanks everyone. I think that I'll stay with the OS. Someone told me that the Saito has a tendency to vibrate.

It looks like I will have a choice of props to use.

To tune the engine down, which prop listed will give the least performance?

Since the engine is so much more than the plane needs, I think a good choice would be an APC 16x4W

My next choice would be a 14x7. It's more than needed, but that engine just loves that size prop

I'm with Minn on this 100%. I use the 16X6 and 16X4 on mine.
The rule of thumb is the longer the prop with less pitch=more thrust with less speed. Shorter the prop with more pitch=more speed and less thrust.
I like my planes to fly slower but when I point them up I like them to pull as much as they can.
Good luck!!

Mike and Gary

Thanks, but I'm a little confused what Gary means when he says thrust vs speed. Am I understanding correctly when you say that the longer prop with less pitch will spin the engine slower, but generate more thrust? And in reverse, a shorter prop with more pitch will spin the engine faster and generate less thrust?

So, a 16x4 will make the plane faster than a 14x7???