Engine basics > Four strokes only

Sugestions for a Peacemaker

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IdRatherBeBuilding:
Im starting a Top Flite Peacemaker and I'd like some input on engine choices.
The Peacemaker is a full fuse bird with a 46" wing at 414sq inches of area. The box calls for a 15 to 29 and the plans show a cox medallion 15 and a version with a veco 19.
I'm actually building 2. One from the kit and another scratched and on a diet. The lighter one is what I plan to do the 4 stroker on. But Im not firm on a 4 stroke. If you guys think 2 stroke would be better, Im completely open to that too. I'm getting back into CL, but have been doing RC with a few 4 stroke engines and love the way the planes present themselves.
I was thinking a of 40 size, but was wondering about the saito or OS 30 for this plane. Im looking for something closer to the veco 19 power.

David Miller

Dave Hull:
IRBB,

Start by looking at the relative weights:

OS FS40S is 12.5 oz.
OS FS30 is 9.56 oz.
OS FS26S is 9.45 oz,
OS FS20 I don't have the weight
Veco .19 BB is 6.2 oz.
Veco .19 is 5.6 oz.
Cox .15 Medallion is 4.24 oz.


The Peacemaker is not a very large airplane. If I recall correctly, George wanted something to fly on a .15 diesel. The front end is not very long, and will not take a large tank. So no thirsty engines, else expect a bit shorter runs. The four strokes have an advantage there, but....

Don't look at the heavier engines as "just adding a few more ounces that I can take back out of the airframe."  The heavier engines you are considering just about double the weight of the engine. The only way to balance properly is to add weight to the tail. So for another 5 oz. in the nose, plan on adding 1.25 oz. to the tail. So your weight went up 6.25 oz. If the plane weighs 28 oz. normally, then you just increased the weight, and the wing loading by over 20%. You are not going to "get that back out" of the airframe. Quite the opposite, the larger, heavier, more powerful engines may require more structure up front to keep them attached.

Not sure which Veco .19 is shown on your plans, but the .19BB (ball bearing) has plenty of horses and to spare to fly the Peacemaker. Anything more and you are just screwing around, which can be fun, but it isn't going to match the airframe and perform well, in my opinion.

I can't imagine a 40 of any type in the Peacemaker unless you just want to go fast and level--and with a ton of tailweight. Which entirely defeats your notion of building one light. The 40 will make short work of a significantly lightened airframe. And, you will undoubtedly have to widen the whole thing just to try to get it in.

So you have to decide what you want to do with it. And, in general, sticking closer to the way the original was built and fitted carries less uncertainty. Yes, engines have improved very significantly. But you may not need/want the extra power, and you have to find a way to manage it. Control line stunt and sport flying is very different from R/C. We never run the engines balls to the wall. Only the control line racing and speed guys do that. And we don't do it with Peacemakers.

Weight has not changed over the years. Too heavy is still too heavy.

Have fun, whatever you decide.

Divot McSlow

PS--I have a Super Combat Streak, which is not much different than a Peacemaker. I flys fine on an old-school OS 30S for power. It just burbles along rich. I also was gifted--and rebuilt--a Jr. Flight Streak. It was equipped with a wire hook to tie on a streamer. With big lead weights attached. And the nose was cut out for a 40. I cut off the hook and rebuilt the nose for a McCoy .19. It flies fine for what it is. Biggest problem is again the limited space for a fuel tank.

IdRatherBeBuilding:
Dave,
Thanks for all the info. I really appreciate it.
I do not want to go fast. I'd like to go as slow as possible in level flight, and follow the same speed in a climb, and that same speed in a dive. Thats why I was thinking 4 stroke with a big low pitch prop to slow it down in the dives.
I knew the Cox would be light, but WoW!

I know I need to just get in the air with anything so I can better understand it all. It has been way too long. I just want to get this one set up as close as I can to get that type of flying I want. It seems a 4 stroke wont be a good choice. At least not in the little Peacemaker. Maybe my next build will be a little bigger and I'll be experienced at least with this plane to better understand it all.

I already have a few options on hand. A Torpedo 19, Enya 15, and an O&R 29.
I also have a few 20 size RC ones laying around. I can turn a venturi to convert them, but as I recall they are all BB engines. So kinda on the heavy side. Probably just better off getting a whole new engine already.

David

Dave Hull:
IRBB(F?),

When you consider engines, a few of the first considerations should include:

1. Is it a Schnuerle ported engine, which will likely run at higher rpm, or is it cross-flow ported?

2. How heavy is it?

3. What do I have to do to it, if anything, to make it run well in a control line plane?

4. How much and what kind of fuel will it need? Will the tank fit? Can I buy that kind of fuel, or do I need to make/doctor my own?

5. If I am flying over pavement, and learning/relearning, is the engine too precious/expensive/nostalgic to risk losing in a crash?

6. Do I need a muffler where I plan to fly? Do I want to damage my hearing without the muffler when you "forget" your ear plugs?

There are others, but these may help you decide what you should start with.


If your K&B .19 is a green head, or pre-green head, they are light, and pretty powerful. If it is not worn out, it should haul a Peacemaker built to a reasonable weight. No muffler.

The Enya is on the small side, but depending on condition, it would haul it around for mild maneuvering.

The O&R is an antique. If you enjoy antiques, you might run it on something smaller/older. Anyone running antiques should be prepared to do repairs, parts hunting, and enjoy that more than actually flying. It would probably haul your Peacemaker around doing the straight and level thing. If in really good shape, it might do a bit more--for a while. Then you are back to the parts thing.

If you want to know about small 4-strokes used in control line, ask Dane "Vegas" Martin. I believe he actually flies them, so his experience is worth ten times my opinions.


Divot McSlow

C.T. Schaefer:
Only for reference, I just completed the Brodak Peacemaker. Not flown yet. Here are the specs. Brodak .25, no muffler, about 2.5 oz tank (and i had to fiddle the front end to fit that!), .5 oz in tail. 24.5 oz overall. fingers crossed.   TS

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