40 engine selection

Our club has a Profile Stunt division with a .40 engine limit
i am building a Cardinal for this event and could use some help choosing the best 40 engine for this application. thanks in advance
Jerry

Tower 40
For more testosterone, get a Stuka STunt 40. Same motor with a little rubbin going on. http://www.clstunt.com/engines.htm

I agree with Mr.Clean. You might also try a Tower/FP.40 with a Macs muffler/10-4 three blade Tornado prop. Mine has an ST.46 & flys very well. I recommend using some quality flap/elevator horns rather than plastic ones that come with the kit. Also a CF pushrod with ball links. Dural gear is a major improvement as well. The Brodak Cardinal is one of the best profile kits out there for PA, imo.
Nils

Mike Havenick had a K&B .40 on a Cardinal. I flew it. I thought it flew great. He is now enamored of an OS of some sort, so he might sell you the K&B cheap.

I flew an OS 40FS in a profile of similar size for about a year. The engine was great, the model was terrible. I finally gave the model away so I would quit messing with it. I will probably build a Cardinal for Brodak's profile event if I go this year. It will most likely have an OS 40FS too.

That said, I am very intrigued by the Stalker/Modusa lineup. Any Stalker devotees here?

Bill

Another vote for the OS 40FP or Tower 40 reworked by Leonard. These engines are Mack trucks and are lighter than the 46LA. The Cardinal will likely be nose heavy anyway so weight is something to think about.

I've just got one of Ian Russell's new Merco 40's and it looks good and knowing Ian it'll run pretty good too!

I suppose you can't wait for Brodak's new 40.

The Stalker 40 is probably next on my 'wants' list.

Of course the cost of these motors in the UK make them much more economically viable than in the US.

Hi Jerry. I am swapping out my ST .46 for an OS .40 SP (reworked) so I can fly in the Dallas contest next weekend. It flew great with the ST but the OS is ore powerful as I understand it. The holes don 't line up, but with a little work it will be in the fuselage by 5pm tonight. I also agreee with the use of carbon fiber pushrods, dural gear, and keep it light, about 40 oz or less. It has lots of wing.

OS-40 surpass. It's a 4-stroke. Bob Z, the 4-stroke guru, swears that it's one of the best 4S' ever made. More power than conventional OS-40FP and such, no wind-up problems, and awesome sound! You may have to shorten Cardinal's nose by an inch or so, du eot extra engine weight. Think about it, man. 4-strokes are the wave of the future.

Ty:
40 oz? Man, that sounds hard to do. My last Cardinal(now deceased) was 44 oz with 40FP and I thought it was about light as I could get it(it reqired 1 oz tail weight). Larry Oakley's modified Cardinal, built as light as he could and all $$kote came in at 43 with K&B 40.
I may also decide to do the Dallas one day profile contest despite not having a decent profile to fly if the weather looks promising. We should start seeing a long range forecast in a couple of days.
Jim

OK, Ok, it was 40.8 oz. This kit had very light wood in it. In fact the fuselage was, in my estimation, too light. Tends to wiggle its tail. The Magician I'm building from Technical Model Products (pre Midwest) has a heavy and stiffer fuselage. Part of the stiffness comes from the top block that forms the canopy and top rear of the fuselage. Also on the Cardinal I didn't cover the fuselage with silkspan, just clear, filler coats and Brodaks Insignia Red. Kept it simple, one decal on the right wing and on the rudder. Black for the canopy like a Cardinals eyes, yellow legs and wheel pants like his feet. I have another kit and will build it differently in small ways. This too will be covered with Poly Span. I got the OS .40 FP installed today. Tomorrow the tank and new pant legs and wheel pants are almost repaired. Rudder has a new section, painted, not pretty, but hey, no appearance points. Now, after all the repairs, I'm sure it will be heavier and will weigh it on my new digital electronic super duper scale just like the one Bat Man would have used if it had been around. Fit that in his belt!

I recently test ran a new Rustler Merco 40 back to back with a reworked Magnum 40 (basically same animal as the FP). With equivalent venturi sizes they turned the same prop at the same rpm with the same 4-2 switch transition. It's reasonably light (similar to the FP) and certainly lighter than the K&B of which I still have one in stock with some enhancement mods if someone wants to make me an offer.

In the states you can pick up a Rustler Merco 40 from RSM Distribution.

Hi BRI!

I'm pleased to hear that about the Merco as UK engine guru Dr John Dixon has said to me that they're a bit light on power.

However as I'm only looking on it as a '35' replacement rather than a 40 I don't suppose this is particularly worrisome.

Cheers

Jerry and Tony: We have been evaluating the new Merco .40 for quite a while and it looks like a winner. After 1/2 hour break-in, we mounted it on "The Plane" - Profile, 51 ounce, 670 square inches. With an 11-6 Master wood, it performed beautifully. Needs less than 4 ounces for the pattern. We used the Powermaster GMA blend, 5% for break-in, 10% thereafter.
We set it up on a Prowler yesterday with similar very good results. The engine seems to work best with a 6 pitch prop. It is steady running and EXTREMELY smooth. The original venturi was too small. I made a new one and sent the information to Ian.
I have no information on availabilty or price but there was an advertisement in Stunt news as I recall.
If you want to use OS engines, I've heard a lot of VERY GOOD feedback on the engines worked by Mr. Neumann (Stuka).
Bob

I got one for christmas!

£87 ($130) including pp here in the UK.

I forgot to mention - the Merco has continually improved with each flight. Seems like the 1/2 hour break-in in was only a start. At a guess, I'd say that you want at leat an hour before you get serious with the engine.
I may have to switch back to 2S engines myself now that a true expert has opened my eyes to the fact that 4 strokes make so little power. Anyone want to buy my 4S collection?!? There's even an M-5 radial in the group.
Bob

WOW! thanks to all for the input,the four stroke engine creeps in there once in a while. i`m still somewhat new at this so am like a sponge trying to soak up all the info...the 4s idea does spark a little intrest. any input on that?. or ill just get one of leonards profile 40s,i know you cant go wrong there(not a plug just a fact) Jerry

So what ventrui dia have you all decided on for the Merco 40 and are you still using the 'spike' NVA?

Tony - yes, we are using the stock (spike) NVA in the Merco. As I recall, the venturi I made has a diameter of 3/16" but I may be wrong, as I did it last fall. The needle valve setting is extremely user friendly and reliable. I can honestly say that all the experience with the Merco .40 is positive. Now, if it only had valves!!!!
Regarding the ongoing .40 engine question, let's jump in with the 4S suggestion. Contrary to the opinions of an "expert", the 4S makes as much or more power than the comparable 2S and is an excellent choice. Very smooth, quiet and requires around 60% of the fuel of a 2S. Forget the extra weight - you won't even notice it. The OS SURPASS .40 is great as is - you don't need any titanium cranks, cams or chains!!!
We have converted approximately 20 planes from 2S to 4S engines and EVERY ONE has flown better. In many cases, we actually DOWNSIZED from a .60 2S to a .53, .52 or .56 4S and the performance was as good or better. At one point, I mounted my SAITO .30 on "The Plane". Even with an all-up weight of around 50 ounces, it did everything well.
On a particularly nasty and turbulent day, Windy was flying a Cardinal in which the ST .60 was replaced with an OS .52 4S. It went through the wind with no problems while another fellow with a piped Jett .60 or .61 was blown out of a number of manuevers. Carlos Serra did a similar change using a SAITO .56 - it was as close to a perfect run as I've ever seen or heard.
If a .40 is your choice, the OS is perfect. For a .30, the SAITO is tops. Once you get to the larger sizes, the SAITO .56 or .72 are tough to beat.
Keep this in mind: Quite a few people have switched from an ST .60 to a SAITO .72 and found that it's way too much power - you just don't need it. I found that out myself when I replaced a very powerful OS FP .40 with an OS .48 4S on my Euclid. I later tried the OS .40 and it was the best the plane ever flew.
Have fun!!! Bob

The last line of my last post should read "I later tried the OS .40 Surpass and..............."
Bob

Hey Bob, Not to hijack this thread but what is the hot setup for an OS 26 venturi.. I saw a mod in a Stunt News article but really don't want to destroy the stock carb. Is anyone making an after market venturi?

Thanks,
Bob

Hi, Bob. As far as I know, there is no aftermarket conversion for fitting a venturi to the OS .26. I've made a number of them for people but it involves cutting the intake pipe. Be advised of this however: Since writing the article and making the conversions, I've had a chance to do a lot more flying and have come to the conclusion that the gain is minimal if any. I tried some planes with both configurations (venturi and stock carb) and was unable to find any real advantage other than a little weight savings. I made a venturi for my SAITO .30 and even though it has a very smooth radius, the original (toilet shape as described by the "expert") performed MUCH better. I guess the engineers and designers at OS and SAITO are a bit smarter than the "expert".
For what it's worth, I designed a venturi for the OS .20 and .26 a few years back. If you're really interested, give me a call. I will make one up for you to try. My number is in the PAMPA register.
Bob

Thanks for the info.. Knowing me I will ponder it for another 6 months and probably just try the stock carb

Why not buy the OS 40 LA?

It costs about $65.00, and is STUNT READY right out of the box. Dee Rice was turning a 12-5 prop last time I saw his rig fly.

Hey, Bob Z.

When you run the four strokes with the RC carb do you find they're a little short on fuel draw? I've had to choke down the intake with some aluminum tubing on all the ones I've tried that way (O.K., O.K., there were only two of them; the old Enya .46 and the .40 Surpass).

Without reducing the choke area a bit they seem to have a tendency to sag in the verticals and above 45 degrees. I had a heck of a time with the .40 in the Doctor at Tucson last year (it wasn't awful at home...but not great either). After returning home I epoxyed in one size smaller aluminum tube and radiused the edges. Now it runs pretty much the same speed everywhere with (maybe) a tiny bit of max power loss.

I get the impression that in order to get the brute power competitive with the two strokes they might have maxed out the choke area and, for our high G and fast acceleration, they're just a bit too big for our use. Any thoughts???

Ted

p.s. I'm still high on the 4-C concept. I'm currently pedalling as fast as I can on a Brodak Nobler for the .40 for VSC. Don't know if I'll get it done but I think it'll be a great combination.

>I get the impression that in
>order to get the brute
>power competitive with the two
>strokes they might have maxed
>out the choke area and,
>for our high G and
>fast acceleration, they're just a
>bit too big for our
>use.

It's funny how people come to the exact same solution on opposite ends of the country. I was discussing this very thing with Pat Johnson two nights ago. The Saito 72 draft tube from the carb (mine has a Pat Johnson venturi setup) to the head is more than TWICE the area of any reasonable sized venturi cross section. This would make me believe I am losing velocity in the draft tube, which just happens to be oriented in the direction of the G's the airplane experiences. I would like to make a reduced sized draft tube with flared ends to accomate the stock hole in the head. The great thing about the Saito is that the draft tube is simply a piece of tubing and not cast like some the others.

I plan on discussing this with the local motor guys (models and cars) at the Stunt Symposium this weekend.

An OS40LA is on my shopping list too!

Ted Fancher - regarding your question on fuel draw. With the Surpass .40 on a profile, "The Plane", the runs were perfect with the stock carb, wired wide open. I used an old Veco T-21C tank, with the classic over/under venting, angled into the slipstream, no muffler and an 11-6W Rev-Up. Many flights and I can't recall a bad run. Now, for the strange behavior: I put the engine on my Euclid (full fuselage, inverted mount) and the runs were inconsistant, showing all symtoms of poor fuel draw. The only tank change was going to a single vent, inboard, front upper corner of the tank. Ran terrible. Tried uniflow, no improvement. Then I put on a muffler and tapped into the pressure and everything fell into place. The runs are great but with muffler pressure the front venting had a slight edge over uniflow.
Dan Banjock is running an ENYA .46 on his Stiletto. Stock carb, wide open, muffler pressure and uniflow. The power is unbelievable. He actually put in an extra head gasket to tame it down.
I fitted a SAITO .40 to "The Plane" an it ran fine on the same set-up as the Surpass. I will try it in the Euclid soon and compare results.
From what we've seen, it's best to keep the muffler pressure option open.
The OS "F" or K&B 4S plugs really work well.
Great results with the GMA fuel but the OS engines that we've tried run best on 10% nitro.
By the way, I have never had to choke down a stock carb.
Bob