which line and engine do you like best?

If you had a Brodak profile Cardinal that was between 42 and 46 OZ. and you wanted to go with the OS LA series, what combination do you think would fly best. 15 lines and the .40 or 18 lines with the .46? I know both are interchangable with the mounting, but what's your thoughts

What does Scott recommend?

Both, depends on what your event is. I just like to see everyone elses opinion. But Scott's say so rules.

I'm no expert, but I've heard Leonard say that the 46 is basically just more power with no weight penalty, so why not go with that? From what I hear, more power is a GOOD thing...

My buddy Ken ran that exact experiment last summer. It made absolutely no practical difference. The plane flew very well on either setup. the biggest problem was the fuel tended to foam, as the plane is a couple seasons old and the nose is getting flexy. other than that, the plane flew fine on either engine, with either set of lines. It did take some minor trimming when switching combinations.

A lot of this is definitely going to depend on how the engine is set up. And don't say "It runs perfectly fine out of the box." We don't run Randy's PA engine "out of the box". You need to change venturis and head shim combinations to make it run the way you want it to run with the prop you are using, altitude, temperature, fuel, etc.

With the 46 LA, I have so far found that it came "out of the box" with a venturi size of .265, 272, .278, .282, .295, and now .303. So, which one are you running? And what is the deck height on the "out of the box" engine? We have already seen that this varies.

Now, you also need to get the prop for the engine. Even if you work with the .40 and get the right venturi and prop for this engine and then just the same venturi and prop with the .46 you may not see much difference. If you go with the best venturi and prop for the .46, then the .46 should be the better power comination. Same (approximate) weight, but 15% more power. That will definitely overcome the difference in drag on the lines and the lines will not be as springy (second benefit). But I would not go by a simple switch of engines, or a comparison of one person's set up to another's until and unless I were to compare all factors.

In calm and mild weather either one will work. The 46 however, (properly set up) will be better in windy conditions, hot conditions, high altitude, and just plainly not slow down as much in the corners. As I have stated multiple times before, we put a 53 with a 13 inch 3-blade prop in Matt's 570 square inch Stuka for a test bed, and never looked back.

Len,

I just got a Tower .40 venturi for my .46. My 9/32 drill bit =.281 slide throug it so I think that Tower is even upping the size of the .40 venturi's. It seems to be about a .285. So, I'm just going to stick with that so that fuel consumption will be a little better.

>Len,
>
>I just got a Tower .40 venturi for my .46. My 9/32 drill
>bit =.281 slide throug it so I think that Tower is even
>upping the size of the .40 venturi's. It seems to be about
>a .285. So, I'm just going to stick with that so that fuel
>consumption will be a little better.
>
>Jim Pollock

OK, now you confused me (not too hard to do, but you done it). Tower didn't make a venturi for their .40. It was RC only. Is this an FP venturi, perhaps, that you got? If so, it was the FP venturi that was being used on the LA and I would assume that as the LA venturi grew in size, so did the one being supplied after the fact for the FP.

Len,

Maybe it was for an OS or a TT, I just know that one came up when I put in a search on their web. Could have been either/or

Definitely go with the .46

Clayton Berry has one with an LA .46 and it runs and flys very well. You just can't have too much power.

I would take the suggestions from Ferocious quite seriously.

Especially as I would have guessed he would prefer a 40 with smaller lines.

While Scott Reisse started this LA40/46 thing here in the NW, and before that was doing something very similar with the 40FP, the fact that we sometimes fly P-40 in this area is a factor.

So I guess the best news to come from Phil's testing is that there is no apparent limitation to performance when deciding on a 40 over a 46.

Go with the 46. The 46 allows a little more margin of error when flying. If the needle is not set perfect it will still fly the pattern with no problem. If a little breeze comes up no problem. As said before if it gets a little to hot outside the 46 will continue to pull strong, no problem. If someone gives you a 40 free. Go with the 46. Grins

I have had both set ups on two different Cardinals. When I built the first on in 2002 I started out with a LA 40 Mac's pipe. It was awsome, but doesn't allow competing P40 contests. I switchted to a Tower 40, same pipe and it also worked well. That airplane is now history.

My new one is 41 oz. LA 40,.280 venturi, 10/22 Powermaster, tongue muffler, 64 ft lines, 10.5 x 4 APC, 9400 rpm's at launch. Line tension is great and when trmmed I think it is already better than both the preveious set ups. I agree with Leonard, make sure that whichever engin it is you are getting the max out of it.

Engine, I would use the .46. I have two and love them as well as any engine ever. I would also use .0018 lines with either the .40 or the .46. I don't like the elastic feeling of .0015 lines with bigger planes. Some like the lower drag of thinner lines. I like the feel of heavier lines.

ONE thing Greg. I haven't told you about the .46 on a mini pipe yet. There is lots of posts about that set up. I will get there after you decide which engine your going to use. Both engines run conventionally, and with a pipe, the 40 will fly the plane. Both engines will run a 4-2-4 break and both will run at the higher rpm’s. I like the higher rpm’s because that the set up that’s comfortable for me. As soon as we can get out to the field I can assess your flying skill and If your ready for the Cardinal and real stunt.

scott(can't teach everything in one weekend)Riese

Addressing the question, I'd choose the 40 with the 015s. The slight increase in power from the 46 would be largely negated by hauling around heavier lines. A 40 will allow you to enter the Cardinal in Profile 40 stunt events. Also you already have a TT46 on your Tanager, and it seems to be way too much motor for that airplane.

Most of the time here in the Northwest we fly in realtively cool temperatures and at lower elevations. Our airplanes perform pretty well with moderate sized engines. What might work for us, power-wise, might not be good for some guys who travel to distant contests or fly in places with consistently hot, thin, dry air.

Greg, your flying skills are better than your equipment right now. You're definately ready for a better flying airplane, as long as you keep it light. The Tanager is much heavier than it needs to be. Use it to practice putting together some of the manuevers you can already do well -- and don't be so attached to it that you don't take some chances to improve your skill and confidence. Unfortunately very few flyers are able to learn the pattern without smacking the ground every now and then.

When you finish your Cardinal you'll be be surprised how much better (and easier) it flies. Keep at it!

I am of the opinion theat either engine is fine. You need to first define your program how you intend to use the model then select the motor best suited for the task. Do you want to fly PA only or PA and Profile40? Do you want to tinker with two different setups? Then get both motors.

I have learned that in the experience of building a real airplane (Lancair); horsepower and cubic inches rule. Also wing loading is a factor and is important as well as airspeed. You can probably use either motor with great success and all the comments herein this post should give you information you probably already know.

In my particular case I bought a 46 but later exchanged it for a 40; had Larry Foster work it over for me and the first time I flew it it was in a 30 plus year old classic fiberglass fuselage Snowbird that weighed over 50 ounces in very poor trimmed condition. The motor handled the plane nicely and seemed to perform in very windy conditions without suffering the maladies of being underpowered and placed 5th in that event in Tuscon, AZ last fall.

Bob Smiley
A Lancair 360 builder/pilot trying to be a modeler

Then again, the .018s would stretch less and give more positive control, according to some (who was it who posted about this in the distant past? Brett?)...