I just bought the Hobbico Avistar. Was wondering what motor I should use.... a .40 or .46? Would the .46 be to much power, or would the .40 be underpowered?

I have never flown before, and will be flying off water... I'm thinking .46 so it can get up to speed with all the water drag.

Thanks!

any decent .40-.46 should pull it just fine for trainer style flying. I recomend the OS .46AX if you can budget your way to it. It's a good match for that airframe, and will carry you over to your second (and third maybe) plane without having to buy a different motor. If you get your hands on a lightly used OS .46FX or NIB/NOS .46FX that'd be a good bet as well.

Fewski,
Go with the 46, as stated the AX, FX or older SF would be a good choice, if your going with a O.S, I would try to stay away from the LA as it's a bit underpowered. I hope you are going to get some instruction of some kind especially since your going to fly off water, flying off land is difficult for a beginner, but flying off water is even harder, I'd hate to see your nice new plane turn into a submarine.

To fly off water you will definitely want the 46 AX or other ball bearing 46 (such as the Thunder Tiger Pro 46). You will need the extra power to help break the "suction" affect of the water flowing past the bottom of the floats. Bernoulli's principle will not be denied. Flying off water is an entirely different art, and you will need instruction.

Most beginners learn to land by dropping the throttle, and letting the ground stop their decent. This technique will not work on water. To land on water, you MUST learn to control the attitude of the plane and allow the plane to sink slowly until the floats contact the water. You must continue flying the plane until its safely on the water, otherwise the floats will be driven below the surface, and the plane will nose over.

You must also take extra precautions to prevent water intruding into the electronics. You must take extra care to ensure all the wood is sealed. Water intruding below the covering WILL soften the balsa, and things will break.

Find a local club, talk to them, and good luck!

Brad

I have a Thunder Tiger .46 Pro in my Avistar and love it. Lots of power and reliable. Only $80 too!

DANGER Will Robinson! Seek professional help. And a flying instructor. Seriously, on the water will make learning 2X harder, at least. You nose over a trainer on the land and you shrug it off. You nose over a plane on the water and, if you get to it while it is still afloat, it's two days drying out and hoping the receiver survives the dunking.

I'd definately recommend the .46 in this case. The .40 LA is a cabable enough engine, but the .46 on the Avistar (a better performer than most trainers), especially one destined to carry the added weight of floats, is a good combination. I have used a Thunder Tiger Pro-46 for several years and it has been a good engine.

Fewski,
You have chosen a great aircraft. The Avistar is my recommendation for a beginner aircraft. Now lets see, you want to fly off water. I won't discourage you, but as a beginner you will not only be facing the challenge of learning to fly, but you will also be challenged by H2O. A float plane will require a lot of power on a clam day, as there will be no wave action and suction builds under the floats. This will require a long take off with a 40 size motor. The 46 size motor will be an improvement, but may still not be enough. A 61 2 stroke would be perfect, but may be too big fot the fire wall. I recommend you get the best 46 2 stroke you can afford. Be patient when taking off, as with the added weight of floats, not to mention the "Drag" effect, a take off will be long and progressive. I also recommend you purchase a flight sim and practice until you can take off, fly and land without crashing every time, then proceed with your trainer. I too recommend you seek help from an experienced R/C Aviator before going on your own. Good Luck and Happy Landings.

Flew an avistar all summer long on a grass field with a ST 40. More than enough power for land lubbers. Water for first flying. Good luck. Get some help with the flying. Try to learn on grass first possibly.

When I got my Avistar it has an OS FP .40 on it..
It was ok but fairly tame.( keep in mind I fly at 6,100 ft)
I replaced it with an OS .45 FSR. Lots of power now.

Balance was perfect with the FP 40 but I had to add some tail weight with the .45

I started off with the Avistar 3 years ago, and have the 46FX on the nose. First off, with this engine, this plane will scream, even with the ground landing equipment. It also gives it a tighter learning curve, because of the semi-semetrical (sp?) wing, so be ready, but your best bet is to GET AN INSTRUCTOR. I tried to fly one time in the beginning without my Instructor, and that was the day that I crashed it good. But I repaired it and kept going.

If you're getting the RTF with the aluminum tube and metal straps for the main wing, be sure that you check the screw alignment and ca the holes! If you're getting the ARF, I would suggest glassing the wing joint with fiberglass tape and epoxy, as this will add more strength for when you get into aerobatic practice.

As for starting off learning to fly on water, I must say to pay attention to the folks up top that have given you sound advice on this angle. A seaplane is nice and it gives you more places to fly, but it is a different world than doing the ground side. Although, if it has snowed in your area, or it will be, you can forego skis and fly off them in powder.

With all that said, good luck and have a happy holiday!

The Avistar is a wonderful plane for a beginner!

It was designed for the OS .40 FP engine, a light engine. The successor to the FP is the LA. With an OS .46 LA and an 11 X 4 prop, the Avistar will do everything but Flip-Flop (some say 3-D).

Pay heed to sscherin: "Balance was perfect with the FP 40 but I had to add some tail weight with the .45"

Note what donhef recomends, if you use the more powerful ball-bearing engines: "I would suggest glassing the wing joint with fiberglass tape and epoxy, as this will add more strength for when you get into aerobatic practice."

The expert can fly an over-powered, nose heavy airplane just fine. The beginner has trouble bringing such a plane to landing.

I once "taught" a relatively new flier to land his Avistar just by taping quarters onto the tail, one at a time, until he was able to land smoothly. Yep, bb 40!

You will soon have more than one airplane and more than one engine. Give yourself a break and put the .46 LA with an 11 X 4 prop on your Avistar. Go Hot-Shot later.

Ken Erickson
30 years helping the airplanes teach people to fly.

I have an avistar with an evolution .46 and absolutely love it. I am new to flying and started out with the os 40 la that came with the rtf. After just a few flights I moved up and got a .46. All I can say is wow, HUGE difference in performance. With it, my avistar flat out screams. The airframe itself is a great choice for beginners. It is very tame to start with. It was my first venture into rc flying. I got an instructor and soloed the first day I was at the field. I have been able to succesfully do some basic aerobatics with this plane and engine combination, and let an experience flyer in my club show me exactly what it was capable of. This is much more than a trainer. It is a great first and second airplane to me. Best advice to give ya. Get a knowledgeable instructor, and get on a buddy box. It ain't worth thinking oh I can do this myself, getting the plane in the air and then not being able to make it down. These are not toys, and they will break your heart.

I just put a .45 ST ABC engine on my first plane (Avistar). I propped it with a 10X6 and thought that would be appropriate until someone suggested 10X4 earlier in this tread. Any thoughts?

BTW it took alot more weight in the tail than I thought, and thats with my battery behind the servos. Has anyone else had to add significant weight to the tail (like 8 quarters maybe more)?

Jeff

wormly81 , a 10" prop is too small for your engine. I would suggest an MAS 11-5. It will give you lots of power when you need it and keep the speed from building too bad. [8D]

I just put Magnum 52 XLS (about $90) with an 11x7 prop, tons of power, unlimited vertical, and at half throttle flys around that the guy just starting out.

I have an ASP 52 which is made suposed to be the same as the Magnum engine. If its similiar, the power and reliability is fantastic but it does tank lots of tanks of fuel through it before it settles down and runs smooth. Its also a bit finicky until it settles down. Mine took about 8 tanks compared to an OS that is good to go after 4-5 tanks. For someone just starting out and wanting to start flying the sooner/better the OS or Thunder Tiger may be a better choices. [8D]

When I built my first Avistar, I had to add 1.5 oz of the Prather sticky lead weights to the underside of the tail, very close to the end of the fuselage. This made it balance just SLIGHTLY nose heavy at the CG, so no issues there. On my second Avistar, I did the same thing, since it also has a .46FX on the nose, BUT, since I got rid of the nose gear and made it a tail dragger, I was able to get rid of .5 oz of the weights. Still is a little nose heavy, but that makes it fly just fine.

I started off with a 10x6 prop with the engine and found out that it wasn't getting the performance I wanted and it took time to get off the ground. Once I put the 11X6 on, the performance changed right away. Definetly buy a few different props to dial yours in to the way you want to fly. I started off using Zinger props, but moved on to the Top Flight Power Points, which did a great job. Plus, with all the strikes I was experiencing while learning to land, I went through 14 in 2 years time. I now use an APC 11X6 and I'm glad I am.

Have fun getting into the air!

Don

I mounted a TT .46PRO on my Avistar but when i tried to balance the plane it was too nose heavy, even placing the 3.1oz RX battery on the tail it still needed more tail weight, so i have a TT .36PRO on the way. If it flies alright an a OS .40la i'm sure the TT .36PRO will be up to the task and 4.5oz lighter than the .46.

I learned on my My Avistar with os 40 and it had plenty of power.

Funny how Hobbico planes are about the only ones that are nose heavy. All the others need nose weight. [8D]

Really? How do you know that? [sm=confused.gif]

Based on experiences of other flyers at my RC club and also based on some 20 planes I have owned, some are still with me, and some are not. Some are ARFs, some are from kits, and some are scratch built from plans. The Hobbicos that I and others have owned "all" were nose heavy! There may be planes from other man. that also tend to be nose heavy when built but I haven't seen any. If there are others I wouldn't mind hearing about them. [8D]

That's interesting. My experience has been a little different. Most recent plane is Seagull Edge 60 size ARF, no nose weight added; H9 Pulse XT ARF, small amount of tail weight required; kit built Sig 1/5 Cub, no nose weight required; Dynaflite Super Decathlon kit, tail weight needed; Dynaflite Chipmunk kit, tail weight added; WM Mach I trainer with an OS 40LA, no nose weight added; H9 Twist 40, no nose weight added; Sig Rascal 40, no nose weight added; GP Venus 40, no nose weight.

In all probability, I have at some time(s) built a plane that required nose weight, but I can't think of one in my recent history. That's why I was intrigued by your statement about "all the others".

Thanks for your comments.

Edit: adding examples I forgot to include initially (!)

Interesting results on your end. It might also be about how close to level you like the plane to balance. I like to see the nose come down about 2" from level. I tried a neautral cg where the nose stayed perfectly level and I didn't like the results when the plane stalled. Instead of nosing down a bit and starting to fly again the plane simply started dropping straight down like an elevator. The plane stayed level because of the lateral balance but lost altitude like crazy! Come to think of it my Super Decathlon did require some tail weight, forgot about that one!! Cheers!

"I tried a neautral cg where the nose stayed perfectly level"

Now is that some form of "new aerodynamics" like the once spouted "new math"?

That point on the Lateral Axis of the aircraft where the nose and tail hang level IS THE CENTER-OF-GRAVITY (CG)

If the nose hangs down, then the actual CG is some distance forward of the point of support.

The CG is established by the equality of weight on either side of the CG. Adding and/or subtracting weight moves the CG and thus the lateral axis.

Stability and instability are functions of the CG and the airfoil's Aerodynamic Center which is -- in subsonic aircraft -- about 25% of the chord. CGs aft of that point increase in unstable situations. CGs forward of that point increase stability.

If you are hanging your model at the 30% of the Mean Aerodynamic Chord and it hangs level, it will fly but less stable than if at 25% of MAC. CGs in most sport models aft of 33% MAC will usually not be a pleasure to fly, and as your "neutral CG" model will easily enter into flat spins.

What some designer writes on plans has no effect on the model if you build it with substantial weight differential distribution. The CG is a balance point. If too far aft add weight forward, or vice versa. Locate that balance point (CG) at 25-28% of the MAC. Try that. If you want to be more lively, then gradually go aft a percent or two at a time.

BTW the Avistar is a good trainer, especially with a reliable .40.