It's a Royal .40. I received it in a trade. I don't know much about it. Could sombody tell me how much it is worth, when it was made, how popular it is?

I had one of these on a Fliteline Scat Cat somewhere around 1990-1991.
I purchased the engine new. I think it was about $80.00 back then?
It ran very well! it was easy going, well behaved engine.
I think I was running a 10x7 wood prop, probably a Top Flite and 15% nitro Red-Max fuel.
It gave the Scat Cat really good speed and vertical penetration.
I would dive for speed, make a high speed pass, then climb verticle until it was just a tiny dot in the sky!
Great plane! Good engine!

It was not a popular engine around here. Other than mine, I remember seeing only one other, on a Royal ARF trainer.
A friend of mine bought it as a combo from Tower Hobbies. It was a pretty high quality ARF for it s day!
His engine also ran very well.

Doug

Nitro Kid,

Are you interested in acquiring another one, possibly for parts, spare, etc...? I've got one that ran mediocre and I no longer use. Been in storage for a long, long time.

It is basically a copy of an OS. I believe the FSR series.

The Royal engines are indeed knock-offs of the older OS FS series. They were made offshore, and the later ones were made by the LEO engine company of Taiwan. You can still get the LEO engines under their own name, and I think they also make engines sold under the Thunder Tiger and MECOA names.

I have a Royal 46, which I used briefly in my LT-40 trainer. It was a bit finicky and I think the throttle/carb is not quite as well built as it might be because throttle response was sloppy sometimes. On the other hand, I only flew it for a while before switching to another engine because the unreliability was holding up my training.

I have no reason to think that the engine could not be made more reliable with very careful adjustment of the low-end needle and general attention to the carb.

Looking at the prices of new .40 engines, your Royal is worth about $20.00 as pictured. If you have the drive washer, prop washer, prop nut and muffer,
You should be able to get $35.00 to $45.00 for it.
Doug

I have a brand new Royal 40 that has never been run, that is missing the high speed needle. Just wondering if anyone has a spare or knows where I can get one.

Thanx,
Ronnie

I have 4 of them. I've had them since Royal came out with them. I was a dealer and my cost was 45 dollars. An old OS 40 or 45 needle valve will work. I really like them. I have used these Royal 40 and 45 exclusively for an unknow number of hours. The only trouble that I have encountered is the muffler likes to vibrate off. Maybe I should balance my props but I don't on these little engines. Oh, yes, the ring on one of the heads wore out. I replaced it and whowee. I'm getting around 12,500 rpm with a zinger 10 x 6 wide blade. That's not bad for an inexpensive engine. I'm using 10 % nitro.