4 stroke or 2 stroke what works better for 3D flying?
 

Hi I am new to 3D ing just want to know whats the go with four strokes to 2 strokes when it comes to 3Ding?

All else being equal, it's about power to weight ratios?

That said, I don't fly glow any more. So for me, it's about what size plane were talking about? The bigger ones will be gas, smaller, electric.

I agree the size of the plane is a factor in this question. It is also a matter of preference. I prefer 4 strokes in glow for 3D. the two stroke will make more power for the same size but the 4 stroke has better low end grunt and throttle respone. If you are hovering with the tail 6" off the ground and need to go the 4 stroke will move first. If you hold full throttle going verticle the two stroke will catch and pass it. Assuming of course the 2 stroke got you out of trouble in the first place :-)

David

Hi Guy's I have a few questions I have pit a OS91 FS in my Seagull FunFly I put a 14/4 at 13.800 rpm does this sound right to you and is this under pitching or over working the motor? I can fit a 15'' prop on her just enough ground clearance would I be better off with a 15/4???

Seagull FunFly 3D5.1 to 5.7 pounds have Os 91FS in it.

I think so. Try a Zinger Pro Series 15x4. I also like the Master Airscrew Scimitar series. These are both light weight quick revving wood props.

I have a APC 15/4 wide blade but haven't yet tried it as just ran the motor in ?

I am just a bit worried about the rpm's im getting as in the book it states practical rpm's is 12.000 and I was getting up near the14.000 area so the APC 14/4 is not the right prop?

I like the Master Airscrew props had a 12x5 on my Diablo and my Fazzer running them with a OS 46AX

The 14x4 is too small. That is what I use on aSaito 72.

Have you thought about a 3 blade prop. Master Airscrew 14x10 would do the trick and give low end performance
for 3Ding.

Wait, I can give you firsthand info on that fs91. 14x4apc is good but not too authority for that engine. A 15x4 is too heavy. Try a 14x6, its best combination of funfly & sports

Ameyam

Thanx Ameyam, I tried the 15x4 today and she was around the 8.000rpm mark motor is still new just breaking her in

no I haven't Cessnaflyer have to have a look into that, I just like hanging the plane off the prop it's heaps fun

http://www.rcuniverse.com/forum/atta...mentid=1947899http://www.rcuniverse.com/forum/atta...mentid=1947899http://www.rcuniverse.com/forum/atta...mentid=1947899http://www.rcuniverse.com/forum/atta...mentid=1947899 not sure why I have 5 pictures appear lol

Oh, I know that airplane very well. Several years back, Phoenix came out with an airplane called Topstar 3d 60 that has the same wing construction. Its broadly like the UCD but the Ucd is longer where this is shorter making it more flip-flop. Its not precision 3d, flies more like a profile. Phoenix also had the Funstar 3d 40 that was even more flipflop, difference being the Topsstar has fixed triangular wing tip upto the ailerons. Recently Phoenix released the one you have and the Hero 3d 40 size.

You dont need to go into rpms for 3d flying that airplane. Just make sure the tank centreline is in line with the carb spray bar and tune the engine by ear with the tank half full & held vertical. Remember, this airplane does not need to go forward to fly (sounds dumb but you will see) and cannot be flown like a rocket

Ameyam

that model is a Seagull FinFly I had a 55AX in her flew it with a 13x6 and a 12x6,5 Master Air screw flew nice at speed tho the 12x6.5 was a bit noisy lolhttp://www.rcuniverse.com/forum/atta...mentid=1948270

The AX 55 responds well to a 12.25x3.75 APC also. It's a little wider blade and is great for 3D. If spped is your thing it stinks :-)


David

I know this plane is not for speed but it fly's not to bad at speed keep's a nice straight line and also does inverted, I had a little prop accident with my thumb so had to give the 3Ding up for a few months as I am mode 2 flyer good all round prop use 12.25 3.3.75 on a 46AX

That Apc is also a good prop size for the 46AX

flip flop?????

flies like a "leaf" falling

Ameyam

Something like a swany profile mojo 40 size with a 55 ax 2 stroke flys like a dream for hard core 3D .Even has a tube running down the fuselage so you don,t break it when you dork it near the ground.Any bigger size planes its the four strokes just because power to weight factor.

I really would of liked a Seagull Harrier 60-90 they seem to look like a really great plane and herd good reports about them pity they stopped building them :(

Its the same airplane, likethe one you have