desertrat, I'm still in the assembly stage on this plane. I've had a hard time finding all the small hardware to put my plane together, I never can find all the right size bolts and nuts for engine mounts and such. But i do have the gas engine mounted and it did fit the original 120 size motor mount that came with the plane. My only goal in putting this large engine on this plane was to save on the cost of fuel. The person I bought the engine from used it on a 14lbs cap 232 72 inch,and said it could hover the plane but did not have complete unlimited vertical climb out, So i figure even if my U CAN DO weighs in at say 9 lbs, with the 1.4 engine it will be putting out 17 lbs of thrust using the recommended 17x8 prop. this i hope will give it the thrust to hover at low RPMs. I'm not sure how this will turn out in real life i do have a 91 four stroke that i could use but my real goal was to cheep-en my fuel cost. when i get it going ill be sure to post about it . there is one more hold up i forgot to mention, the wing i got was covered backward the checker board patter was on top and the red white and blue colors was on the bottom so I'm been waiting for Great planes to send my the replacement wing and it not here on Friday as they promised.

Hi Dale,
This was the first time I dealt with them. Unless you are lucky in that you can purchase locally, you will often spend $5-7 for S/H. In the past, I've used paper manufactured by VitaCal (http://www.vitachrome.com) and purchased from Wm. K. Walthers, Inc. (http://www.walthers.com/exec/productinfo/768-5020). 5 times more expensive, but nevertheless, great decal paper. I find the Beldecal paper similar, but some times tends to cause "balling up" of certain inks (like black in particular). For five times less the price than what I was previously paying... Its a good deal to me. BTW, Walthers also charges $7 for S/H.

Flew mine for the first time today. OS 1.08 with slimline pitts and rev-up 16 x 4.5. No cowl yet.

I hadn't flown for over a year (been real busy). The first flight lasted 20 seconds due to a dead stick. The rest of the flights were a joy. Hovers very nice at 1/3 to 1/2. Torque rolls needed some left alerion to keep them moving good. Rolls seem a little slow, may be getting blowback.

Last flight of the day I was getting mutiple torque rolls and super easy harriers. finished with a harrier landing and packed up. I think I'll keep her.

More flights tomarrow!!!!

Mike

Supertiger: How are you doing on the 1.4 project? Hope it will works out. Best Regards... ... Captinjohn

About a week ago, I got a chance to fly the UCD with a more rearward CG than the 5.5" that I started out with. I haven't installed the cowl on the ST 90 yet. The GP motor mount that came with the UCD was swapped out for the next smaller size, which saved 2.5 ounces of nose weight. The ST 90 was moved back as far as it would go on the mount to push the CG back even farther.

With an APC 14x6, the UCD balanced at 6.0" back and flew better than the 5.5" CG. Then I used a lighter 14x6 wood Zinger and got the CG back near 6.5" which made the UCD even more to fly. At 6.5" back with a nearly empty fuel tank, it just barely begins showing the first signs of being tailheavy. At this point, it looks like my UCD will end up with the CG about 6.5" back.

The initial test flights had shown a need for some right thrust and I figured about 2 degrees would be a good place to start. Since I was swapping motor mounts, this was a good time to add the right thrust. That's when I discovered that my UCD has over 1 degree of left thrust built into the firewall. Therefore I ended up using a 3 degree Ernst thrust plate to get back to about 2 degrees of right thrust.

Now with the 6.5" CG and the 2 degrees of right thrust, my UCD is much easier to hover and throw around in 3D flight. Once I get the MCP figured out, I suspect the UCD is going to end up being one of my all time favorite planes!

Been flying my UCD for 2 weeks now haveing a blast with it ,,using a MDS 148,,Can you say BLAST OFF out of a hover !!!!!!!I like POWER ),,and it IS way over kill,,going to put my YS91 on it ,,I have found that the 2-56 rods for the ailerons are to week,and the 2-56 on the rudder was a joke,,switched to 4-40 , and fixed the bending a bowing,,With full flapperons using the 2-56 The ailerons were sluggish 4-40 fixed that,,and the 4-40 on the rudder made it solid,I could not get a good flatspin and I got a tip from (on on the edge ) I now us full down flapps in the inverted spin and it is flat ,I can keep adding power and it will then do a climbing flat spin,,or get the power just right and it stay's in one spot spinning Cool !,,Thanks On The Edge ,,,,,,,Hope everyone has as much fun with theirs as I am with mine.,,
Happy Flying,,

Dave,
thanks for the ST90 info. I have been debating for several weeks about putting my ST90 on it. I will also go w/ a moosecan.

As soon as I get my new menace going, I will start swapping out motors.

Fred,

Would love to see a video of that climbing or hovering flat spin...sounds cool and will give me something to practice. What technique are you using to get it into the inverted flat and where is your CG?

Dave/Fred - didn't both of you read my ucando review? I covered the right thrust issue and control rods in detail to try & help you avoid those issues. http://www.rcuniverse.com/magcover.php These reviews are honest guides on these products. No sugar coating. Many of the tips and caveats I got from this thread but it is quite long (this will likely be post 510!) so the reviews can give you a good overall list of things to look out for without reading all 500+ posts if your in a hurry.

My U-CAN-DO still has the CG at 5" but my next project is to cut a hatch on the bottom of the fuse to move the battery back and mount it in there. I want to push it back to the 6" range myself as it seems this is where it is coming alive for most here.

I did read the review..but it was after the fact that I was allready flying mine,,it is a true and to the point review good job !
AS for me getting the flatspin ..I stall the plane which is darn hard to do ,but I get it stopped switch to 3D rates,,add full down flapps then full down ele. full Right rudder full Left aileron and hole it for 2 turns,then start adding power and feed Right Aileron back in real slow the more power you add the flatter it getts and eventually it just stop's falling and does a Sit & Spin,,COOL !,,keep adding power and it will start climbing the climb is slow but it does. I have my CG 6 1/4 back..no broblems with it this far back yet ,,It does a nice wing tip spinn with the CG this far back also ,,I am going to take the MDS 148 off and put my YS 91 on it..and see what happens ,,)
Have A Great Weekend & Burn Lots Nitro ,,

Marc,
You did a fantastic job on the UCD review! Contgratulations!
But my UCD was already built and flying before your review was posted.

I agree 100% about using 4-40 pushrods on the ailerons. I never even bothered to try the 2-56 pushrods because of the distance between the servo and the aileron horn.

Just like you, I also used the 2-56 pushrods for the elevator and they haven't been a problem. But I mounted both of the elevator servos 180 degrees from yours in order to keep the pushrod geometry more symmetrical.

With that large of a rudder, I skipped the rudder pushrod and went with a pull-pull with the servo mounted on the bottom of the fuselage.

Today is the first Sunday in three weeks that it hasn't rained so I can finally resume flight testing of several different mousse cans to try to get more power out of the ST 90 while reducing the weight. I've been tempted to put a TT 120 in the nose since it weighs exactly the same as an OS 108. But so far the extra 1/2 pound of dead weight and the already-too-nose-heavy issue have stopped me.

What size of moosecan would work for the ST G-909 you are planning to put on the UCD? I assume you want to use the 15x4W prop for the UCD. Wouldn't that require a mega-size moosecan to work right?

Would about the same size moosecan work on a Supertiger .75? And would it give enough power for hover???? Thanks Captinjohn

I suspect the APC 15x4 would work better than the APC 14x6, but I don't have a 15x4 to find out for sure.

Based on my previous experiences with mousse can pipes on .25 to .46 size engines, I would have sworn a ST 90 would have needed a larger mousse can. Surprisingly, I've had the best results with a 1.75" x 6.5" can....which is the same size can that work best on my .40 to .46 engines. So far the ST 90 w/MCP is turning an APC 14x6 at 11,700......which has resulted in a major increase in vertical performance on the UCD.

The ST 75 with a stock muffler should easily hover a UCD. Just don't expect it to leap out of vertical hover. However if the MCP experiment on the ST 90 is any indication, the ST 75 should respond well to a 1.75" x 6.5" mousse can and give you pretty darned good acceleration out of a vertical hover.

But rather than duplicate information that is already in the Fun Fly forum, I'd suggest going to this thread for the latest info about the project to boost the power output of the ST 90:
http://www.rcuniverse.com/showthread...448#post451112]

I've made a couple of changes to my U Can Do to try and improve its behavior.

The first was to run a program to mvoe the ailerons up as spoilers with up elevator and down with down elevator (basically what Mecam suggested) This definitely improved the elevators and harriers, but there was still a bit of wing rock.

Next I took the wingtips off. This helped the plane stall and spin a bit better. I managed to get a climbing flat spin once, but I can't seem to duplicate it. I'm running the CG at 6", I'll probably move it back some more.

Last change was to add a strake in front of the fin. This is an attempt to tame the strong pitch to the belly with rudder input. One of the fixes for a pitch to the belly is to lower the stab. It's not all that easy to do, so I thought that adding some fuselage side area above the stab might have the same effect. I'll find out if it's any help tomorrow.

David

We have one in the club & with a OS .61 FS, it is nose heavy, which is hard to believe, because the nose is so short & fuse so long. Servos are in tail, and batteries and receiver right on top of the trailing edge.

I'm getting one and I'm going to put an Enya 1.20 in it.

Bill

both are very well made engines...as far as the power to displacement goes..i would have to lean towards the ys...but saito's are well liked for there light weight...at least the 72 is, it weighs in about 1/2 pound lighter than the O.S 70....i haven't owned a YS in about 10 years, but i do know for a fact that saito's are operator friendly as far as critical needle adjustments go....i would think that the new saito 100 and the ys 91 are very equal.....as far as power...and haven't checked but would also think the saito would way somewhat less......

Please Read Entirely:
I'll make this as brief as possible, but it must be mentioned. A very nice gentleman (Bill M), whom I'd never met before, showed up at the field w/ a UCD. Since I've had mine on B/O w/ Tower for over 2mo., and hadn't seen one in person, I eagerly approached him w/ the usual questions (engine, CG etc.). I continued to explain my B/O issue when he told me that his LHS (about 100 miles away) had them in stock. So, to verify, He, on HIS cell phone, called the store, spoke to the owner (Frank) and had the UCD reserved for me. Well, as if that weren't enough, he also offered to pick the plane up for me and bring it over 2 days later. 100 miles!!! Needless to say, an offer I could'nt refuse. Well, the transaction was made and the UCD was, in fact, delivered to me 2 DAYS LATER!! I am now the proud owner of one of the hottest, hard to find ARF's (in it's size), thanks to a very nice, honest individual. A PERFECT stranger. You meet the nicest people in this hobby. Bill, may the R/C Gods reign upon your every flight. Happy landings!!!!!!!!Steve

The nose moment is not that short. The distance between firewall and leading edge is more than the length of the supplied fuel tank.

Very cool Bill and Frank, way to take care of a guy! It's nice to hear stories like that.

Well, got mine out on Sunday in the breeze here (Denver area). Could not really tell a lot about the handling because of the wind. I had the CG at 5.5" for the first flight and the plane sure reacts to control inputs. I could tell that I need to add right thrust (a bunch) I needed full right rudder to hang the plane vertically. Man, with a little wind the UCD just floats down to the runway with a tail wheel first landing that is so cool looking. Engine started behaving strange and had no thrust (YS 120). Got it home and started looking and found a broken valve spring. Well, hopefully parts get here this week and then back out for more fun.

Dale

Dale: Too many RPM,s can break valve springs--- did the valve hit the top of the piston at all?? Hope not John

John,

I got lucky in that the spring only broke off at about 1 turn from the bottom. I have always run it below 9k RPM, so it is probably just one of those things. I think that this just caused the intake valve to float at much lower RPM. Parts are on order, so hopefully I will be back in the air this weekend (if the weather is cooperative). I really want to wring this plane out after all the stuff in this thread.

Dale

I flew my U Can Do yesterday, but on my first attempt the motor
was idling too high so I thought I would turn from the paved runway onto the grass at about 5 mph and the landing gear block sheared right off. Needless to say I was a little miffed as
everything that could go wrong while building this thing did. I have never had so many goofy things happen while building an airplane or should I say assembling one. I thought I would post this as a warning to those who are building one or are flying one
already.

The block appeared to have been hot glued on to the fuse.
I would suugest to either screw it on or at least try to strengthen
it with something (epoxy or ca) triangle stock etc.


It did fly great and lands like a trainer I would like to thank everyone for posting their mods on this forum as I used most of them ( pull pull on rudder, tank on cg,4-40 rods, added right thrust)

Thanks Doc

Hi Doc,
Looks like you forgot one required UCD MOD....
See http://www.rcuniverse.com/showthread...983#post379771

I beefed this area up big time, using triangular stock and epoxy.
Also. this isn't a good plane to handle (i.e. carry) by the landing gear like I see some do.

Best of luck!!

I used 2 nylon 1/4x20 bolts on my ole Cap 231EX to hold the gear on.
On a rough landing (sometimes not so rough):
1. The gear would sheer off the bolt heads
2. The wheel pants would punchure the wings
Sometimes the plane would belly flop on to of the gear causing fuse damage...
3. Typically this would end my flying for the day...

I ended up going back to a 4-40 with blind nut! I dunno what the right answer is, but I have yet to pull out my gear plate since switching back to metal bolts..

-Chris