I am looking at getting a UCD 46 but I am unsure of what size 2 stroke engine would be adequate. I am leaning towards a GMS .47. Do I need more HP?

It will fly with the 47 but you might want more power if you are planning on hovering. An ASP or Magnum 52 or Leo 56 or an OS 50sx would all be good choices.

I am running a Super Tigre G51 2 stroke on mine with a 12 x 4 Zinger prop and it will not hover. I had to add a lot of weight to the nose to keep it from being so tail heavy. That may have had something to do with it.

Personally I have a Saito 91 on mine and like it a lot. The 91 is very close in weight to a 46-50 and is a four stroke so has better low end throttle response and plenty of power even at 5000+ feet. I did have an OS 50 in it for a while and it was fun and would hover OK at almost full throttle, but not like it will with the 91. Main problem with the 91 is cost. The Magnum, ASP and Leo are much cheaper and would do respectably well.

four stroke best you can get for it saito 100

two stroke os 91 fx or evo 100

If you want a 2C the .91's are the only real choice. Less than a .61 is not enough and the .91's weigh the same as the .61's so there's no reason to get a .61 2C. The .50's will hover it but barely.

I'd go Magnum .91 XLS 2C or a .91-1.00 4C.

i have one that im getting ready to build and am planning on putting a 1.08 magnum 2 stroke on the nose this should be a very good combo.

mark

4-strokes are a must for 3d and tourqe rolling, i have a satio 1.00 on mine, great combo, highly recomended...

I also have a Saito in mine and agree its a good match. You don't need all the power but on the other hand you don't have to use it either. I'm having a problem getting a prop nut to use with my Great Planes aluminum spinner. I noticed your pic didn't show a spinner. Any suggestions?
k.o.

I must be missing something on the 4-stroke issue. When I read the Saito specs, the .91 only delivers 1.6 hp. Maybe torque is the issue.

It looks like I should be in the .76 2-stroke class or greater.

Ths GMS .76 @ 2.5 bhp and $100 looks good. That is if GMS makes a decent engine.

Cost is an issue so if the GMS is not a good choice maybe a Thunder Tiger or a Super Tiger would do.

BHP on a 2 stroke is up at the top of the power band. The 4 strokers have high torque on the low end letting you swing a larger, less pitch prop for 3D. I would go with a 4 stroker for 3D.
Just my .02

A YS 63S or Satio 82 would be a more appropiate choice for this plane than the larger heavier 91-100 size fourstrokes. Vertical should still be unlimited with the proper prop selection.

what am i missing here ultra lite engine + 4 to 6 ounces of lead makes a liter plane than a saito 100 perfect cg

I needed nose weight with the satio 1.00 in mine, not a whole lot, but with everything in stock locations it needed like 3-4oz to get it to the 3d cg.

The .46 UCD is not a light plane, probably in the 6lb area, but I don't have one to weigh. The YS .63 or Saito.82 are marginal for 3D on a 6lb plane IMO.

I'd go for the .91 or 1.00 4C or a cheaper route is the .91 Magnum 2C


That's just my $0.02

You may want to try the Tiger Shark .56 2-stroke. It is .46 size/weight and (almost) has .61 power. You can get it from Kangke USA. It works well in my H9 Twist.

Whatever mine weighed it was plenty light enough, it would float on its wings, hang on the prop at half throttle, and do all the 3d manuvers that i could do.

It is a fairly large "40" size plane you have to keep in mind, something like 900+ squares

A good 2 stroke 60 size would work well on the UCD 46.I have a 70 FS in mine,weight 5.5 lbs,flys really light and will hover no problem.The os 70FS will rev the 14x4W at arround 9800 rpm and Im pretty sure the 60FX will turn it over 10K.


later


jeang

I just put a YS .63 s on my ucd .46. To get more weight to the front, I ended up putting the 6v battery under the tank and as close to the firewall as possible. This should be plenty of motor for pulling out of a hover but not sure about authority. The motor is swinging a 14x4W at about 10,200rpm with wildcat ys 20/20 and an o.s. #f plug.

I have found a solution that has really surprised me. My first Ucan do 46 I was running a OS.46FXH with an APC 11.5x4 with good results. Lost that bird to battery failure in the air. Now I put an OS.50SXH with a 12x4 and Hobbico tuned muffler on the new plane. The plane weighs 5 lb 14 oz balanced at 5 3/4 it is the best combination yet. The plane hovers at half power and comes out of the hole like a 40%er. The heli version of the .50 has a lot more power than the airplane version. And the larger head keeps things in the cowl cool. The carb is built with midrange performance in mind. If you think about it everything a heli needs we need doing 3-D. Stay cool in a cowled in low airflow installation, Excellent midrange and tons of power wide open. I'm at 2000 feet MSL. Another bonus of the heli is you could run 30% nitro with out any fear of the engine not liking it. In fact the instructions say to run 15-30%. I'm running 15% Powermaster in mine. I know it sounds far fetched but I would put the vertical performance up against any U can do set up I've seen yet. The real benefit is the plane is under 6 lbs. This keeps the wing loading so light the maneuverability is unreal. Light wing loading is the best attribute to the U Can Do .46. Once your over six pounds all you have is a lead brick that can go straight up. I'm into airplanes that can fly on the wing not just the prop shaft. Putting Saito 100's on a .46 U Can Do will kill the wing loading. Might as well take up model rockets. They will fly very similar. Jason

K&B 61 might work well. Same weight as a 46.

Mike

If you use anything but an OS.50SXH, Tower pipe, and an APC 12x4 your wasting your time, fuel, and airspace. End of story!!!

Bob Sawyer

Guys,
Take the time to read the post Jason posted. Trust me you do not want to put anything but the O.S. .50 SX/H on your .46. Jason and I were both flying ours at the same time side by side and his vertical was twice that of mine. I was running the same setup except I had the O.S. .50 SX aircraft version. There is a huge difference. I ordered my SX/H that same day. Don’t waste your time with all the other stuff. We have done the research for you.

Dude,
This is WAY too much engine for a .46

FLUTTER!!!!!!!!!!!!!!

I don't like what I am hearing! LOL

You guys are recommending the most expensive engines out there. My guess is that the GMS .74 has enough power but will have too much weight (about 10 oz more). Although Zippy (above) said he had to add weight to the nose. I really do not want high wing loading, but the darn OS 50 is really high priced.