I am putting together a pattern plane with a inverted engine. I don't want to put a on board glow because of additional weight.

I have been torn between the new Evolution 61 engine or the OS 61. So I thought I would asked the experts for there advice.

Which one ??????

Thanks
Gary

If you don't need to restrict yourself to a .61 capacity, install either a .75 or a .91 with the same crankcase dimensions as the .61. Examples of engines worth considering are the OS FX .91, the Tower .75, the GMS .76 ringed, the ST .90 or the .91 Magnum/ASP clones.

Key to a successful inverted installtion is correct tank placement and a good carburetor with a dependable finely tunable idle. I can't speak for the Evolution's carb, but everyone except the most profoundly prejudiced would agree that OS carbs set the benchmark for tunability and consistency.

Of course, if you are restricted to .61, disregard the above!

FWIW, if I were putting together a pattern ship with a .61, of the two engines you suggest, I wouldn't hesitate to choose the OS .61 FX, because I know they carburate well.

Harry,

Thanks for the reply

I am stuck with a 12 oz tank. The plane is a World Models Intruder. So a .61 would be my limit. I have heard 4 strokes will load up inverted quicker than a two stroke.

You made a very good point about the carburater. Not shure how good a Evolution carb is. But OS is known for a great carb.

Gary

If you want the .61, look at the Tower engine.

http://www.towerhobbies.com/products/towg0161.html

It has almost top power in the class, and has a true chromed bore that won't
wear out. Right now it comes with 6 free Tower glow plugs. (they are good)
If you buy it with the Tower Club deal, the warranty is extended to 4 years.
Tower has all the parts in stock, and the cost is half price of the others, plus
if you ever need parts....Tower ships the the same day to you for free.

The engine already has the "tuned muffler", and the main needle can be used
in the regular "front" position, or as a rear needle set-up. Look for a Tower
Savers Code, and get an additional $25.00 off a $150.00 order.

I wonder if Tower needs a salesman.

FBD.

Hi Dave,

I thought about the Tower .61 is is tempting. What attracted me to the Evolution is that it had a great write up in Fly RC and claims the position of the plug prevents flame outs. The writer was Dave Geike (SP? Sorry) he seemed skeptical over the flame out claim but was very impressed. I am not sure how the Tower or Evolution engine will handle inverted. I am attempting to put together a very simple trouble free, what every that means in RC, pattern plan for practice. The manufacturer recommends an inverted 4 stroke. But I am not to sure how trouble free a inverted 4 stroke would be. Most of my 4 strokes have on board igniters. Trying to avoid that on this plane. But maybe I have no choice. I thought the 2 stroke would be a good compromise.

Thanks
Gary