Way cool Mac's pipe

Just a heads up for profile flyers. Mac's have a pipe number 6652 for .40 size engines that besides tilting out it also tilts twards the engine mounts. On the plane I put it on the muffler outlet is inline with the fuse. So I didn't have to rebend the landing gear like I did on some other planes. Just thought I'd give the heads up on it. Steve D.

Hmmm? Phil Brown's clearing house apparently didn't have a web site listing, or at least I didn't find one there.

It's http://www.macspro.com/

This is a standard-bends version: {img]

The web site doean't mention the new model 6652. All of these "one piece mufflers" have a single price. They are all $29.95. Anyone who hasn't held one won't believe how light in weight they are until you have picked one up!

K.

When I called to order a 6650 the jent on the other end told me that the 6650 was out of stock, but they had this 6652. And yes it isn't on the web site. he told me about it. If I was web savy I would be able to post a pic of my Majician with one on it. BTW, I gained 300 rpm w/this pipe and also lost 1 1/2 oz from the stock LA muffler.

Your only five years behind in your FIND. I've worked out all of the bugs to make this set up work. MANY POSTING ON THE MAC'S PIPE.

Scott(you'll like it) RIESE

aww crumps

LAST EDITED ON Aug-13-02 AT 10:00 PM (CDT)

Way cool indeed, except after the flight! Scott's our Guru on the Mac's Mufflers. I have seen them running for the last 3 seasons and am running one now, a #6650 on an OS .46LA. Lots of power, but I'm trying to get Big Art and Randy Aero tube mufflers to try running bigger props. The Mac's Mufflers have to get 10k + rpm to give any power. Most our fields are noise sensetive, so the Mac's is a good setup, and they work with relatively cheap props. Also, as long as they are cool, they make a good handle for starting the engine (left hand grasps pipe while right hand runs electric starter) and carrying the airplane down the trail thru the blackberries to the truck. I didn't know about the #6652 pipe, and will check it out for a P.40 project. Steve

Edit: Don't mind Scott, he's due for another pain killer (bad back). Could you email me the photo of your #6652 pipe on the Magician? <[email protected]> I'll try to post it or send it to somebody who can.

STEVE, Right now I'm working on the 25FP with the Mac's set up.
Heres the enginegs that I've tryed. The 46 Bull Ring shows alot of Promise. The ST-60 I need a plane to try it in. All of my big ships are set up for PA-61
Os 25fp
OS 35fp
OS 40fp
Os 46la
Tower 40
ST-46 bull ring
ST-51
ST-60 small case

Scott(Mac's pipes are kool)Riese

Do those pipes have any sort of baffle in them? I've seen a few of them working alright at local contests.

The 6650 is an especially useful muffler for me. I originally bought one for my LA 46's but the same model also fits the FP 35 and 40 and the Thunder Tiger 42, all of which I have. Very convenient. Oh, it also fits the LA 40. Anybody who has one of these engines, needs to run muffled, AND doesn't have a Mac's is really missing the boat IMHO.

Scott. can you tell us, one more time, the setups, prop and rpm wise that you've found working well with the LA .40 and Macs' pipe?

Grish 10-4 three blades are getting very hard to find now that they are no longer in business.

According to Scott's list, he hasn't run an LA .40, just the .46.
However, my HSFB (High School Flyin'Buddy) Mike Haverly ran a Tower .40 with a #6650 and found the 11-4 APC to be "da bomb". It may need a tad of trimming to get the rpm up. I'm running an LA .46, one gasket, .292" venturi/.156 NVA with either coarse or fine Bruline filter, about 13% nitro/24% oil, mostly castor and 11.5 x 4 APC. The 12.25 x 3.75 has to be trimmed to 11" or less to get enough rpm. Mine will pull 11k+ peaked on the 11.5 x 4, but launch at 10.2k. This is extremely close to what Scott recommended, just a bit more venturi, a dash more nitro and one head gasket less. The filter makes up for the venturi, and we need it for the mole hills. The Humongus doesn't turn tight without slowing a lot, and needs the power. By getting more power and higher peak rpm on the 11.5 x 4, I can launch richer, so it leans out overhead and boosts power up top. When in doubt, more power can't hurt. I have not experimented much with fuel with this setup, but Scott has. The amount of nitro will affect pipe tuning some, but (stock) it's pretty agreeable to anything typically used for stunt. Scott gave me some sizes for opening the stinger for more power, but I haven't had time to mess with it yet. This mod will make the muffler less adaptable for the FP.35>LA .46 swapping. Steve D sent the picture of the #6652 muffler, and that looks more agreeable packaging-wise...no LG problems. I'm going to try to post the picture. By the way, last Saturday, I flew most of the day, and found that I had to continually lean the NV to get the 10.2k...maybe 2 turns! This means you need a tach, and the fuel mileage will change through the day. Is this typical? I have a .40LA on the way, and will test it in the Humdingus ASAP. Steve

I have a .40LA on the way, and will test it in the Humdingus ASAP. Steve

Hi Steve, I'm running the .46 about the same way as you except 10% nitro, stck venturi, remote needle, and an extra gasket. I launch ~10,100 or so. I can tell by the sound of the exhaust in the muffler when it's right. real sweetheart of a run.

I tried the LA .40 on the pipe, and couldn't get it to run the same way, even with the APC 11-4. I'm running three head gaskets, a standard venturi, .280 dia, with an OS needle valve assy through the middle. I replaced the pipe with a tongue muffler and tried several props. The best runs were on a special prop I got from Tony Naccarato when I was in Burbank the last time. I don't have a pitch guage so I can't tell you what the pitch is, but the legnth is 12 inches. I intend to get a few more of these from him as it ran very good on it. I used no muffler pressure, about 9K and 5.3 second laps on the Cardinal.

I'd still like to find the magic connection for this engine and the Mac's pipe though. I seem to recall the Grish prop being part of the mix.

I have just installed one of these on a Brodak 38 Special biplane powered by an LA .40. You are rifgt that the weight does go down but, using the same old style 11X5 Top Flite prop added MUCH power, and increased the fuel economy from 7'30" to 9'28"! I have flown this set up about 15 times and the latest thing to have been accomplished by the 38 Special was a verticle square 8! Not a competitive maneuver be it did do this! Amazing increase in power and attendant confidence! Phil Spillman