Hello,

I have been flying an Avistar 40 (High Wing Advanced Trainer, Semi Symmetrical Wing) for a while and feel pretty confortable flying it. Nice landings with Little or no bounce on paved runway.

Last night while flying my main wing sheared into two pices mid air turning my trusty Avistar into a lawn dart. I still haven't quite figured out what happened. I was about 75% Throttle (TT .46 pro, 10x6 master airscrew) going into a fairly mild climb and Whammo! The Left side of the wing ripped off followed by the right site and the show bagan!

My question is this. I have a U-Can-Do 3D (UCD3D) .46 that I am going to put together anyway. I haven't got an engine for it yet but now I have a TT .46 Pro to drop in it. This is not what I intended (wanted bigger) but it is lying on the bench now anyway and I haven't got the new engine for it yet. Still undecided on that one.

If I put the .46 in it without the intention of doing any 3D, do you think I can handle this plane only having trainer experience? I fly Real Flight 3D frequently and actually find it almost easier to fly the EXTRA 300s thatnmany of the trainers. I can fly the EXTRA and a CAP 232 pretty well in RF3D. I used RF3D to learn on before I started with my Avistar and soloed on my second flight and have not had an instructor since so I think RF3D is a pretty good indicator for me to asses my capabilities to some extent.

I have heard the UCD 3D is a pretty slow flyer and a good landing aircraft. Is this correct?

My dilema is I paid $135 for the UCD 3D and don't really want to drop another $100 on a new AVISTAR if I can move up to the UCD 3D.

There is still quite a bit of flying time left for the season (North Dakota... Brrr) and I want to work on my skills some more this season. I am buiding an EXTRA 300s that I am hoping to be able to fly sometime next season so I really want as much stick time as I can get this season.

Opinions?

Do I risk the $135 UCD, or spend another $100 on a new Avistar.

I know it is hard to answer this question without knowing my proficiency level but I "feel" that I can make the transition if I stick to low rates.

From one novice to another ....

The reason the UCD3D flies slow is that it is a 3D plane. By definition, 3d means that you are performing manouvers with the wings "stalled". 3D means that you give up the use of the lift characteristics of the wing so that the only forces exerted on the plane are thrust, torque, gravity, and drag. Giving up lift only happens easily at low speed.

Thus, the UCD3D is best flown slow.

No doubt that the plane flies well at speed as well, but that is not it's intended use.

If you are asking whether you are ready for the plane, well, there is only one way to find out. As for whether you can do 3d, well, give yourself some altitude, and try! Just b aware that the control surfaces of 3D planes are designed to be effective in the prop-wash of the engine. Thus, they are all close to the fuse, and over-sized. They work not by changing the aerodynamics of the wing, but by deflecting the surface in the airflow of the propeller. Thus, using them at full rates when at speed will potentially damage the plane. Further, the surfaces are so big that they exert strong forces on all the control rods and servos, making them more prone to flutter, etc. They are designed to be used at slow speeds, keep the plane slow.

gus

I wouldn't go putting a much bigger engine than recommended in the UCD anyway. The airframe is built light enough that it can hover on the recommended engine. If you over power it, you will have structural failure. The UCD is not built for high speed flight, and it can't handle it, so be sure to stay on the throttle and don't let the airspeed build up. Beyond that, you should be fine flying it. Check the instructions about prop selection as well. A 6" pitch prop is more than you need, you're better off with a larger diameter, smaller pitch prop.

I convinced a new member of my club to do that very thing... go from a trainer to the U-Can-Do-46 with a Saito .72...

He absolutely LOVES it... it takes off and lands MUCH easier than his trainer. He has a plane that isn't fighting him.

The .72 makes it JUMP off the ground...

If you can fly your trainer with no problems... the UCANDO46 will be an easy step up.

Keep the throws low, and above ALL.... keep the throttle at 1/2 or lower... speed will get you with an aerobatic plane until you are used to it...

At 1/2 or below, it's a floater and gives you plenty of time to react.

Great, Gald to hear that!

I am convinced that I should save the $100 on a new Avistar and go ahead with the UCD.

I will not be doing any 3D this year, so with that in mind do you think the TT .46 Pro will be okay in this plane? I can't see why not.

Thanks for all the great replies! I love this place!

RiffRaff

The TT .46 Pro should fly it quite well... tho it may not have full unlimited vertical...

The plane comes in at 5.5 lbs give or take, and can be tailheavy... My buddy used the Saito .72 and put the rudder on pull-pull to get the weight forward... the TT 46 weighs only .5 oz. more...

You may end up putting noseweight in it...

Yup!

In fact 8 Oz of nose weight right in front of the firewall to balance at 5" off LE! Wasn't expecting it to be THAT much. Maybe I need a lead spinner? [X(]


I went with the standard dual elevator servo setup though.

RiffRaff,

What size prop are you going to use.
I use 11x5 APC props on my TT Pro 46's
It is a good combination, it won't give you too much speed.

Bill

I decided to go with a Saito 72 in this machine and am transplanting the Pro 46 to a Tower Trainer for my son.

As long as you keep to low rates and balance the model exactly in the middle of the recommendation, you should do fine. It still might be worth getting an experienced pilot to help you out with the first few flights, even if it's only to give you confidence.

Just keep an eye on the speed of the model, both in take-off and landing. It's much better to err on the fast side, even if you bounce a lot on landing, than experiencing all that nasty things that can happen if you are too slow.

-David C.

Very good advice. I have found that speed can be your friend in a lot of situations.

FYI

After flying this model, I find it easier to fly than my Avistar when set up for very low rates, a little exponential and just casual flying. I am having some minor difficulty with the landing only because the plane floats too much and actually lands much slower than I was expecting. A few bounces.

In short, I think the money saved building a second avistar and moving up to this plane turned out to e a great choice. Granted, I am not flying this plane anywhere near its potential, but she;s in the air and that will come with time!


RiffRaff

Just wondering if you epoxied the winghalves together, the stock clasps just dont do it.

Yup,

The Avistar wing halves were epoxied with 30 minute epoxie. This was the ARF and not the RTF kit. Only the RTF has the clamped/bolted wing joiner.

I suspect what happened was the weekend before the wing failure, I misjudged the distance away from me and clipped the left wing in a bean field while landing. I suspect that this stressed the joint and started crack initiation.

Purely speculative, but it would explain it.

RiffRaff

mordib: I lost a Funtana just a month ago and have the Saito 72 out of it. I am considering getting the UCD 46 and was just wondering. Did you have any problems with mounting the 72 on such a narrow fuse?.... Did it take a lot of carving on the cowl to make room? and Do you remember how much weight you added to the nose to balance it?

RiffRaff here,

I can answer this question as I just went through this.

The Saito 72 fits very nicely. No carving of the cown at all other than the front cooling inlet and access holes for the muffler, needle adjustment etc. The 72 fits entirely under the cowl.

I had to add about 8 oz of lead in front of the firewall to get mine to balance at 4.75" off of LE. I did install the dual elevator servos in the taiol per the instructions though. Some guys go one servo with a pull pull to save weight.

RiffRaff

Sorry for jumping on this a bit late, but I think my signature says it all

hookedonrc, It would be interesing to hear an comparison if you decide to go with the UCD, my Funtana is still going strong despite my best efforts... (broke the fuse in half on a cartwheel after a deadstick,went back together like a jigsaw puzzle)....

tiggernva: I will keep you posted. I was very disappointed after my Funtana went in. Not the plane's fault, it was mine. Was doing aeleron roles on high rates, exited upside down. No problem, pulled back to bring it on through in a split "S" cause I had enough altitude. On my way through at the bottom, I moved my thumb to far to the right on the aeleron control and with the high rates it came around and went straight in. I did love the characteristics of the plane and really enjoyed flying it. Just didn't get enough time with it before the crash. I still have to do some engine repair. It bent and pulled out the muffler at the threads, pulling off some on the cylinder head, and it bent one of the valve push rods. Like I said, it may be a while, but I will keep you posted.

btw: RiffRaff, thanks for the info. I have an US 60 on the bench about 1/2 finished, then I may get a chance to do the UCD46

Glad it all worked out RiffRaff. I saw one fly this summer with the Saito 80 in it. Very impressive! He also had the floating problem on landing. I thought he was going to overshoot the runway, then all of a sudden he slammed the nose in the air and it stopped right away and just settled right in. Very cool!

I went from Lt-40 to Sig SE.....fun aint it..now

Check you engine thrust...if you have too much down thrust..then you will have trimmed the plane at speed, elevator up..( to check, get some altitude..at 3/4 throttle hands off level flight...throttle down just above stall speed, does it noes up?? if it does then the engine is pulling the planes attitude down..so when you slow to land..the nose pitchs up and it will sail on you.. just a thought

Hookedonrc,
Sorry to hear about your Funtana, maybe you could get another; last time I looked my LHS had one in stock....

By the sounds of it the Funtana and the UCD behave similarly on landing; maybe its the thick symmetrical wing they use for 3D.... Mine would either float right on down the runway or if I tried to bring it in slow it would just suddenly drop, flattening the gear. I think the solution is to fly it to the ground rather about a foot from the ground hoping it will settle....

When I was flying my Funtana, I had 1 to 2 clicks of throttle in it on landing. It helped me tremendously. You just don't want too much. BTW: I did nothing to mine except mount the engine and fly. I checked the incidence but figured with the angled firewall the right thrust was already there. Never had a problem. Maybe I was just lucky.

tiggerinva: I thought about another Funtana, but the shops here are out and on back order. It has been a real big seller. (Of course we have only 3 shops to check.) Well it's 6:45am and I gotta go...headed to the field. We are hosting a scout troop today. Will have G2 Simulators for them to practice, 4-5 trainers and buddy boxes so they can all get a chance to fly, and several of our best flyers will do aerobatic flying during lunch. Should work out to be a great day.