General New Plane Needs Engine

Derek

Derek

Well-Known Member
If all goes well, I may get the opportunity to get my hands on a Top Flite P-51 with a 64" wingspan. The way I understand it is that this is a balsa kit that is half built and has no engine. Now, everything I fly is electric. I just like the simplicity....but this is a great opportunity and I'll give more details later on if everything works out.

In the meantime, I'd like to research different engines for this plane. In the specs, it states "Engine Required: 2-stroke .60-.91 cu in or 4-stroke .91-1.20 cu in". Where would be a good place to look for a reliable engine? What differences are there between the 2 stroke and 4 stroke?
 
Tony

Tony

Staff member
In my 67" F4U, I have an OS 61. I have never flown this plane because I suck at monokote but this engine in bench testing had tons of power.

And the differences in two and four stroke are just that, the stroke. 2 stroke fires on every up stroke of the piston and has no other moving parts other than the piston, ring, wrist pin, rod and crank. A 4 stroke fires on every other up stroke of the engine and uses an intake valve and exhaust valve, actuated by a camshaft that is run off the crankshaft to let air in and let air out.

2 strokes are going to rev higher so you can use a shallower prop and get a very "speedy" sound out of the plane. 4 strokes are going to not rev as high, but you can use a prop with more pitch since this engine produces more torque.

I hope these work, but here are two gifs that show how a two and four stroke work. Two uses exact timing to move the air/fuel mix into the cyl, but because of the way it does this, you are sending raw fuel out of the exhaust when it gets sucked in. a 4 stroke will do this as well, but just not as bad. This is also known to increase the flight time on a 4 stroke since it's more efficient.

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Tony

Tony

Staff member
It gets a LOT more detailed in how things work in these two engines. But that is the basics.
 
Derek

Derek

Well-Known Member
ok, let me ask you this....I really don't care if the plane is "speedy". I would much rather have the plane be able to handle long and straight vertical climbs. Would the 4 stroke engine be better suited for this?
 
Tony

Tony

Staff member
Either one would do it. I will bet money that my .61 two stroke in my F4U will do an unlimited vertical as will my .91 four stroke in my decathlon. You are going to pay more for a 4 stroke and you have to do more maintenance to it, but the sound is quite a bit better. Maybe I will head out to the garage and fire up my two engines and let you hear each one. I think I have a video somewhere of it though. Just have to find it.

If you are wanting more of a scale sound, then 4 stroke is where it's at.
 
Tony

Tony

Staff member
Okay, scratch teh video. I couldn't find the video I shot so I went out to just fire them up. I got a car battery all charged up to power the starter and glow driver, fueled both engines (and blew fuel right into the carb and through the exhaust of the F4U, oops) and was ready to start them. My battery powered glow driver is dead and will not take a charge and my glow driver that hooks to my power panel is MIA, nowhere to be found... I think it's time to clean up the studio...
 
Derek

Derek

Well-Known Member
Ok well, as I only have electric, I don't know what Im shopping for. Can you find a couple links to a few engines that I should be looking at?
 
Tony

Tony

Staff member
By far the most common, and most used engine is OS. It's the standard that every other manufacturer bases their engine on. The 4 stroke that I have in the decathlon is an off brand though, and I can't remember the name. But be ready to spend a couple hundred to about five hundred on an engine.

And know some of the terms. ABC is going to mean Aluminum Brass & Chrome. This is what the sleeve is made out of and is usually for non ringed engines. ABN is Aluminum Brass Nickle and again, for non ringed engines. Then there is ABL which I think is an OS term that means Advanced Bimetallic Liner. This is for ringed engines and is an incredibly hard metal.

Here is an OS engine with pipe (that you may or may not use, your manual will tell you what muffler to use. I'm using a Pitt's style muffler in my F4U). It's just under $200.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAESD&P=0

Here is an OS 4 stroke.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAVCS&P=SM

Of course you could go complete scale with a radial engine :chuckles:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZVB2&P=0
 
RandyDSok

RandyDSok

Well-Known Member
I can hear the scale guy's now...

The real P-51's never had unlimited vertical.... LMAO...


The Top Flight P-51's are very well liked.... The one I saw ( it had other hardware problems and didn't fly at that time, but did another.... and then one time too many because he crashed it ) was a real looker... I think you'll love it.... and at that size, I'd suggest the 4 stroke also ( only cause no one I know of can afford a radial )
 
Tony

Tony

Staff member
Welcome to engines. There are thousands of options out there, you just have to find the one that is right for you. That is the hard part lol.
 
Derek

Derek

Well-Known Member
lmao....I'm an electric flyer...how will I know what engine is "right for me"? ha ha ha
 
Derek

Derek

Well-Known Member
an electric conversion would probably be the easiest solution and it would have components that I'm use to....but I'm also thinking that it would be cool to learn a bit about a gasser.
 
D.O.G.

D.O.G.

Goblin 380 Supporter
mooserider

mooserider

Active Member
Derek, I hope I'm' not too late here! What you want is a 4-stroke for sure! The sound.... you can't beat it! Much quieter, much more realistic sound. If you hear the in the 'wild' (not recorded), a 2-stroke sounds very high and whinny, whereas a 4-stroke sounds more like a real planes (lower and smoother). Once you make the *right* decision on a 4-stroke, you just need to decide if you want some extra power. If you're looking for a mellow flyer, go with a .91, if you want something with power, get a 1.20.

Tony:
In my 67" F4U, I have an OS 61. I have never flown this plane because I suck at monokote
Click to expand...
*shakes head* Tony, you have more excuses for not flying than I have crashed planes!

- - - Updated - - -

Also, as you mentioned, when you don't know a lot about something like nitros (personally I'm clueless about electric), it's hare to know which of the dozens of options to pick. SO I can make it easy. Go with a YS engine, like a 115. OS is another good one, but YS is awesome, well established, and I doubt you'll find anyone here that disagrees that they're great engines.

Here's YS's page for their 115's:
http://www.ysengines.us/products/engines/YS115FZ_S/default
http://www.ysengines.us/products/engines/YS115_cdi/default
http://www.ysengines.us/products/engines/YS115FZ_WS/default

Lowest price to highest. But you'd be happy with any of them. If you're thinking this is going to be your only nitro model, go with the cheapest one.

Hope it helps some.

Cheers!
 
Derek

Derek

Well-Known Member
Thanks moose! I appreciate those suggestions. I've got some "thinking" to do.

I'll be picking up the plane in two weeks. Maybe we can sort out an engine option then.
 
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