RE: Everything I need to complete an Avistar
 

the os 40 la in my hobbico superstar i have is a great little engine it's been crashed crank first twice hard and it runs great. i know a guy who has 2 46 la's he never has to fiddle with it much. for the price you can't go wrong.

RE: Everything I need to complete an Avistar
 

Stick with the LA. The major advantages with a bearing engine, usually more power, smoother running, heavier weight, and another thing you have to coddle because rust & dirt can ruin them. You'd be wise to stick with the LA if a friend has one already. There's nothing wrong with it and a fine match for the Avistar. In all my engines I use fuel that contains some castor (I'll even add castor to bring the lubrication % up) , use whatever OS suggests and you should be fine.

RE: Everything I need to complete an Avistar
 

Picking out parts is the fun part, don't let it be stressful. I know myself, my pocketbook has a lot to say what I pick. I like good quality and absolutely hate cheap garbage. So with that thinking I usually try to end with at least good equipment. Be very open minded and work with whatever you pick. I think too many guys give up on something when all it takes is just working with it for awhile. Your initial choices are fine.

RE: Everything I need to complete an Avistar
 

Well, I'd like to thank everyone again for helping me out, and giving me their input.

I'll let you guys know how it goes, once the plane arrives :)

RE: Everything I need to complete an Avistar
 

http://www.youtube.com/watch?v=luEtn...os=dqs9AyiNChc

Screw all of the stuff! Go electric!

:-)

In all honesty it is the best 40 size trainer out there!

Enjoy and good Luck,

Ed

OH and it's tuff too.... :-)

http://www.youtube.com/watch?v=cqU8z...os=BiiSFO6LV8Y

RE: Everything I need to complete an Avistar
 

You will love this plane. I have three Avistars that I use to teach people to fly with. Two of them still have the stock .40 la that came with them and they both fly just fine. The .46 La will be good trouble free engine for you and the 11x6 apc prop is a good match for that engine. Who ever suggested the covering iron above also gave good advice. The "chink in the armor" of this plane is the covering, don't be surprised to find a ton of wrinkles and bubbles when you get it. Just iron them down and go over all the seams at least once before you fly it. Pay special attention to the seam on the leading edge of the wing before each day of flying. If this seam comes loose in flight, half wing the covering can get ripped off before you can land. Ask me how I know;)

RE: Everything I need to complete an Avistar
 

How do you know that? :P

RE: Everything I need to complete an Avistar
 

LOL. my camera is out of commission right now or I would take a pic and show you. I have big patch on the left wing of one of my Avistars because the seam came loose in flight and ripped about a 6" x 8" piece of covering off the top. One of these days I will totally replace the covering, but for now it has a big ugly patch. I was able to fly and land it safely, but if the covering had come off the entire top of the wing, it could have become uncontrollable and crashed. ;)

RE: Everything I need to complete an Avistar
 

the covering came off the leading edge of another club members wing, the plane was crunched pretty good.

RE: Everything I need to complete an Avistar
 

Everyone has a prop preference. Talk to the people you know who are running the 46LA and get their recommendations. My brother and I have a 46LA on a 40 size trainer and we like the way a 11x5 prop works on it.

While you're training, I recommend using Master Airscrew glass filled nylon props like this:
http://www3.omnimodels.com/cgi-bin/w...I=MASQ1336&P=7 They make lots of sizes.
They are pretty flexible so they do not break as easily as wood props or APC composite props.

Carrell

RE: Everything I need to complete an Avistar
 

The LA class engines come with a sleeve bearing. It is called a "hydrodynamic" bearing in the mechanical industry. Typically, this type bearing is made of a sintered metal such as brass. When you add lubricant, the same is absorbed into the bearing surface by capillary action and excess oil forms a lubricating oil film. When the shaft rotates, it forms a fluid film which increases the oil pressure in the space between the shaft and the bearing surface lifting the shaft surface off the bearing surface and keeping the shaft in suspension. This prevents wear caused by rubbing of the shaft and the bearing surfaces.

So much for a scientific explaination of the effect in "plain" english. Getting to the real deal,

1) Theoretically there should be no metal to metal contact in the bearing but practically this does not happen and shaft play increases with use

2) There is greater resistance to rotation (called fluid drag) meaning these engines produce lower power than the comparable ball bearing ones and also react marginally slower to throttle

3) The hydrodynamic bearing is mostly suited for operation with constant speeds and low radial loads. If the speed is reduced, fluid pressure and hence lubrication effect is reduced as well. This increases likelyhood of wear and reduces power delivery further. Since we dont always fly at constant throttle,sleeve bearings are not desirable

4) When you start or stop the rotation, there is effectively no lubrication. The lubrication effect at this time will come from the thin oil film on the bearing surface and lubrication effect will increase once the shaft gains speed as capillary action will bring more lubricant to the bearing surface.

As against this, ball bearing supported cranks encounter only rolling friction instead of sliding (rolling friction is lower) and therefore are easier to turn (i.e. deliver more power more quickly) and last longer. Then again, there are more moving parts that you need to be sure are lubricated, but that isint so difficult as the lubricant is part of the fuel. Also, you can replace the ball bearings but not the sleeve bearing as it is part of the casting.
You can check out the performance figures of a LA class engine against that of a AX class in light of what I have just explained. For all the above reasons, LA class engines produce less power and dont last as long as the AX.

Sleeve bearings are very common in industry where there are high constant speeds and low radial loads involved. In fact, majority of air-conditioning plant water chiller manufacturers use the same as their operating speeds are fairly fixed. Most of them, however, have started moving to oil-free magnetic levitation bearings in which the suspension is achieved through magnetic fields; that is something much beyond the hobby for now. And since the time I learnt this theory, there has been a lot of improvement in metallurgy and newer techniques will make the LA class last more but the underlying restrictions are the same.

Any one who knows better, please correct me on any errors I may have made.

PHEW! Let me be the first to say that that was a lot of technical data but you could use the underlying concepts. :):D

As a beginner, you really need not worry regarding this, just that the LA engines are less powerful and therefore cheaper. When you go to aerobatics you will need that extra power that the AXs will provide. There are two options: either start with the LA & go for an AX later when you want it or damage your LA OR take the AX now and be more careful with it. You dont need to stress out, just take the decision with all the pros and cons weighed

Ameyam:D

RE: Everything I need to complete an Avistar
 

Wow, you went above and beyond with the information.

Thank you so much!

RE: Everything I need to complete an Avistar
 

I still think setting your first plane up with the LA is a good idea. Don't worry about "the next step." Keep your trainer totally intact and get everything new for your next plane, assuming there is a next plane. That way, if (when) you crash it, you still have the trainer ready to go while you're repairing the other plane.

RE: Everything I need to complete an Avistar
 

Why do you think the La line is soo much cheaper?? answer: because they use cheeeeper parts and it does not run as well. Take the advise of people that have been in this hobby for a long time!! STAYAWAYFROMTHELAENGINELINEANDGOWITHTHE55AX ITWILLHELPYOUNOWANDLATER!!


LAISAPIECEOFJUNK!!!!!

RE: Everything I need to complete an Avistar
 

From someone who has had his knuckles dinged by model plane engines since the 1960's the OS LA 46 is a good dependable motor; however I would suggest investing in a electric starter because sometimes the LAs are a little cold blooded in the morning. FWIW a buddy and I are building 2 90" B17 bombers and were both mounting OS LA motors for their dependability and their fuel economy. I also have 2 OS 55AX, but my LAs are more dependable and cost 1/2 as much.

RE: Everything I need to complete an Avistar
 

Thanks for your input on the LA

What's the difference between the Twin Needle and Air bleed?

RE: Everything I need to complete an Avistar
 

The LAengines run OK but Ijust hate that leaky plastic backplate. Irecommend the Thunder Tiger GP42, its tough , reliable and makes good power. The price is right too.

RE: Everything I need to complete an Avistar
 

Where did you get that?

Ameyam

RE: Everything I need to complete an Avistar
 

Thumbs up for the 40LA. I have two LA's and I love both of them. There's a place in life for the LA!

My 40LA was a gift and although there's a sentimental attachment, it does the job I ask of it perfectly. My 40LA is in my LT-40 and I love flying it. But here's the deal, I love how all my airplanes fly and I fly them all, all the time.

I love how my CG 300 Extra Enya 120R flies, I love how my Ultimate 40 46AX flies - same for CG Cub Saito 91, Edge Saito FA-80, SPAD Thunder Tiger Pro46. All totally different, just the way I like it.

The point I'm trying to make is that it's relative - I find every bit as much enjoyment flying my trainer as I do flat out flying my Extra.

It's all about appreciation! And besides, regardless of the bearings in my 40LA, it'll outlast me 100% guaranteed.

RE: Everything I need to complete an Avistar
 

Twin needle is a better design. High speed needle and low speed needle are opposite each other and both adjust fuel mixture.
On an air bleed, the idle mixture is controlled by a separate screw that adjusts air flow as opposed to adjusting fuel flow.

RE: Everything I need to complete an Avistar
 

I was doing reading up on engines in general, and I found out there's two differenent kind of carbs.