I am getting ready to build a 72" One Design. I am still debating
whether to use a glow such as a Moki , Super Tiger or a gas.
Which ever way it will be around 30cc. I already own a ST3000
that is a very good and reliable engine.

Check out this fine 25cc engine at www.gcbmrc.com . At $195.00, the price is right and there is lots of features.
Regards,
glowplugboy

I vote gas. :-)

That 25cc engine weighs in at 64oz. that is super heavy for a 72 inch WS.airframe. Thats 4lbs of engine alone,Woweee!!

Yep, but the gas engines are heavy but powerful. I truly like your
ST3000 --------- Do a twin and grab another one. Or go with a 25 - 32cc and let it rip - just make sure you have enough surface area to keep that brick in the air. Good luck!

Fiddler

Yes sir, the way I like to look at it is the GCBM R/C 25cc is one pound lighter than a US 25 and 12 oz. heavier than a G23. It beats both in the power department by about 20%, and the price is right. It has been used in airframes such as this one with sucess.

Have you considered an OS 1.60? Lots of power, 32 oz and about $260.

Anthony

Exactly how do you want this plane to fly? What type of flying do you like to do? Personally I'd stay away from gas on this one due to wieght- Who cares about power its the wieght that'll get ya. You don't want a 14lb 72" plane.
-Jon

Depending on the weight of the plane and how you intend to fly it, you might want to consider the RCS 1.4.

http://www.rcshowcase.com/RCS%20Engines.htm

Thanks guys for the responses. The more I think about it I am leaning toward the ST 3000 that I have. It is one of the later models "K" series that has a ST4500 carb with a bushing in the barrel to restrict the flow. If i use this or a moki I should be able to keep the weight down to around 10 1/2 to 12 lb range. The ST was on a 80" sport plane (a Q-500 blowed up and modified to be more aerobatic ) it weighed 10 1/2 lbs. The performance was awsome. The One Design I am planning to sport fly and try to learn some 3-D. Yes I have been bitten by the 3-D bug too!!!!!
I like the looks of the One Design and there is not a dozen of them at the field when you go flying. I like the other planes but I just want something a little different.

Hey Johnny_Rebel
If you are the same Johnny Reb from the other forum, then you will be delighted to know that I have taken some of your ofttimes caustic advice to heart. I have a H9 1/4 cap, and I was going to put a ZDZ40 on it. Upon further review, I have decided to go with the O.S. 1.60 FX. It will come out a pound lighter, and I don't have to build a motor box or make any other special (heavy) mods to the airframe. I have a Midwest extra 300 kit, and I will use it as my entry into gas engines, and I will try to keep the cap as light as possible.

Gas all the way

Holy Mackeral! A 10-1/2 year old thread!

Any older and the third choice would have been coal fired steam. ;-)

Glow if under 7 pounds. Gas if over 10 pounds. In the gray area - dealer's choice.

My vote would be something in the 1.4 to 1.6 range. A 72" airplane for good aerobatic performance should not weigh more then 10.5 lbs. You will find howerver that the One design is not a 3D airplane. It does well for sport scale like aerobatics. If I was building this airplane I would be looking to a YS 120-140 or Saito 180.

as per me, anything 120 & above would be gas. of course, it can be model specific

ameyam

I really love the ST, but this days, GAS!
You can get cheap and reliable engine and it's a great save on the long run!
Try one of this: http://www.hobbyking.com/hobbyking/s..._8HP_33cc.html or this: http://www.hobbyking.com/hobbyking/s...HP_2_94kw.html
I don't have one (Yet...) but have seen them working and it's a charm.