Hi! So I bought a black horse models "diablo 3d" and it had a broken wing. So I went to the store and we looked on a replacement wing for it but unforunately it was broken aswell!!

Now I had a OS 55ax for the diablo, but the store were out of small 3D planes so we began discussing other options in the 60 size. He tells me that you have to have an engine with fuel-pump (only made for 4-strokes) to be able to fly good 3D and those engines are like $450 here in sweden (.71-.91 sized engines). The motivation is that when you hover, the engine is unable to pump all the way from the bottom of the fuel tank (while in a hover) . Now... I really want a 3d plane but those prices on the engines are killing me... not to mention that you also need bigger servos

The question is, do you really need a four-stroke fuel pumping engine to be able to perform in 3D?

cheers

Pete

Absolutely not, a good 2-stroker will 3-D just fine. I usually put a larger than standard engine in, if the ARF calls for a .90 2 stroke,I put in a 1.00 to 1.20 if it will fit without too much cutting & carving. Fuel delivery & transition are very important to 3-D, a pump or Cline is not always necessary, usually the further the tank is from the engine, the more you need a fuel system. 4-strokers do have more pulling power in the lower throttle ranges, but if you have enough thrust/weight with a 2-stroke, it will be just fine, that is probably more critical than which engine type. I have a 7.25 lb Fusion w/ OS 1.20 AX and a 9.5 lb Velox with same engine, guess which plane hovers longer at a lower throttle setting without over heating?

I preffer a 4 stroke but a 2 stroke works. The transfer is better with a good 4 stroke but throttle managment is all timing in a hover.

David

Good thing nobody told me that before I had those hundreds of flights with my Funtana with a 2 stroke on it. They fly 3d just fine.

I use EP ... no issues! Hehehehee ... seriously ... for me 2C or 4C for 3D is the same, you need to know the engine that's all, both are different, apples and oranges. I enjoyed using both.

Yes, I guess all those World Class flyers using Da , 3W and other large 2stroke motors
will like to know they DO NOT know what they are doing....[sm=75_75.gif]

How do I know if an engine has a fuel pump? Someone told me its some little piece on the back of the motor. Could someone explain this to me?

2 stroke all the way, and don't be concerned about a fuel pump, he was most likely trying to get you to pay his rent for the month.

Bob

some have them where the back plate of the crankcase is located. You don't need a pump with a fourstroke unless you want to mount the tank on the CG. Best engine that I've used personally for a .40 size 3D machine is the Saito .82. No pump needed.

I have an OS 46 AX and an OS 55 AX. Both are reliable to a fault, and the 55 AX seems to have just as much torque as a four-stroke. No problem with unlimited vertical and hovering there.

NorfolkSouthern

I have both 2 and 4strks for flying 3D. As someone mentioned, it's all in knowing how to tune. My 2strks transition just as good or better with a Macs header and MCP as my Saito's-and I have several of each. The one thing I like about a two stroke is there is less to damage for someone in the learning stages of DOD flying (rolling harriers, inverted harriers etc, etc.). I personally like the sound of a good two stroke in my face anyway

I cant use the poll because I have 4 strokes, pumped and non. I also have 2 strokes pumped and non. All are used for 3D and each has its place.
Adam

like i read i think it comes back to what you like. there is no need to have a pump with tank in the correct place. If you already have the 55ax then its the best motor to use if you have a 4 stroke then thats going to suit you better its all much the muchness to what your want. If you want an ultimate 3d plane for the 55ax a mojo 40 is a perfect match here is a link http://www.swanyshouse.com/index.aspx and just remember to have fun for thats what its all about

I like 4 strokes. I've used 2 strokes, that 55ax is a great engine.
Why I like 4 strokes.....
http://www.youtube.com/watch?v=fsHEj-mz5mY

Gee whiz - I guess that DA-50 I got is worthless for 3D.

I have used both four storkes and two strokes for all kinds of model flying. They all work well if you select the proper size engine and set it up properly. I prefer the two stroke for power to weight ratio and smoothness, but prefer the four stroke for noise reduction.

Ron

While DA,3W & other gas engines are 2 strokes, I dont consider them the same class. Larger (50cc & up) gas engines have tons of thrust in the lower RPM's compared to 2 stroke glow, it comes with the ablity to swing 10-12 pitch props easily. I prefer 2 stroke glow because its cheaper engine, fuel, repairs, reliability. A good quality 2-stroker with good thrust/weight will do the job, my best example: Fusion .90 ARF, 7.25 lbs , OS 1.20 AX, no pump or Cline, hovers at 1/3 throttle all day long(in cool weather)., goes vertical out of sight in a couple seconds. What could be better, a rocket maybe??!!

Both work But listening to a 22stroke whine gets annoying quick, put a MCP or Macs on it and it gets worst[>:] Saito 4444 strokes rule the 3d planes in my area.

Pump is not needed, thats just more wieght and something to go wrong.

Certainly NOT in my area...

The majority of my 3D is with a 55AX on a SPAD 3D plane. It is not pretty but it will harrier ad hover all day long. The 55AX hardly breaks a sweat with the APC 12x4 I have on it. I also use 4 Strokes on my Balsa Planes. There is nothing cool than the saound of a 4 stroke. I think it is a matter of preference in the Glow engine world. With the right set up 4 strokes or two stroke you will be just fine.