These test stand numbers are from a production NR Speed 13 purchased from Buddy at SMT Distributing LLC, at www.smtdistributing.com
We will be posting more info as it is available.

BTW, we are also testing coupler material provided by patternpilot1, seems to be working very well so far. Thanks, Scott.

The first numbers are with a Hatori 650 pipe, also being tested are the old Mac's "flat back" pipe, Mac's Muffled Tuned Pipe, the NR pipe and Mac's Quiet Pipe. We are attempting to make the runs when atmospheric conditions are similiar, not easy in central AL this time of year.

1. NR Speed 13 production engine w/10mm carb, PowerMaster 10/22 fuel, NR plug as supplied with the engine, NR straight header, APC 11x7 prop, Hatori 650 long chamber pipe, 16 5/8" to first baffle: rpm 15,800 peaked.

2. The same Speed 13 w/10 mm carb, Cool Power 15%, NR plug as supplied with the engine, NR 1" rise header, APC 11x7 prop, old Mac's flatback pipe at 14 3/4" to beginning of convergence: rpm 15,700 peaked. Humidity and temp slightly higher than Hatori data.

3. Same Speed 13 w/10mm carb, Cool Power 15%, same NR plug that came with the engine, NR 1" rise header, APC 11x8 prop, Hatori 650 long chamber pipe at 17 1/4" to first baffle: rpm 14,800 peaked. This set up seems to duplicate what Dave P. saw with the NR 50400 pipe and NR 2" rise header, both systems set with slight gap between header and pipe. More Rs may be available, but this is major power, with no trial and error necessary.

Nice place to start. Thanks for the report, Jim.
Chris...

Nice info Jim.

Do you ever measure thrust?

Tim

No plans at present. Static thrust data is really only good for very low speeds and changes greatly with prop changes. A 14x4 will make great static thrust but would be useless for our purposes

That is humming right along.

Other than the black case, what is the difference between this engine and other engines sold with the aluminum case at place like www.planethobby.com and www.klasskotemo.com.

Actually, this is one of the original natural aluminum case engines with the NR Speed 13 purple head, same as the black case engine except for the case color.

Anybody running this engine on 0% nitro?

CP, I don't know if anybody has, I ran mine on 10% VP with Caster blend oil. The motor ran very well on a 11X7 1/2 Rev up, I saw 14,800 and I'm sure it would go higher if I had let it go ..

Dave

Adding to Jim's infor
5% nitro 18% oil
APC 11x8 14,200 rpm
rpm pipe is Hatori 606 16.5 inches
stock glow plug
9mm Carb

To continue adding to Jim's data. Mine is running on a speed plane. I get 17,450 with a 10x8 on break in fuel. 15.5% nitro, 22% oil and the balance methanol. Mine has the 10mm carb and is pumped. I run a custom carbon fiber tuned pipe since I can not justify the weight of the 50400 pipe, even though it performs very well. This thing is a powerhouse and likes to rev. With over 180 exhaust timing it is not very happy under 15k.

Pylonracr,

Which pump are you using and exactly how is it plumbed?

Thanks,
Jim

Jim,
Pretty simple. I use the Perry VP-30 regulating pump. Plumbing is easy, tap the backplate for reference pressure. This goes to the end of the pump with the supplied tubing. Pump inlet is from the tank clunk, outlet to the carb. Do not use pressure, just vent the tank to atmosphere.

The pump tuning is a little sensitive. A little too much pressure and it will not transition because it is too rich in the middle, a little too low and it will lean out upstairs. Some patience on the test stand and you will get it. I only pumped mine because I have the 10mm carb and the tank is too low with the engine mounted upright. I built this plane around the engine and don't have the room to side mount it. If I build another plane for it I will side mount it and will probably not need the pump. The fuel draw is not great with the 10mm carb, but with proper tank placement they will fly.

Scott

Thanks, I have used the Perry pump with other engines, but wanted to learn what your set up was and why the pump was needed.

Old thread I know. When you guys are measuring the pipe length, are you measuring from the face of the piston in the exhaust port or from the glow plug?

I will quote Dub Jett "Pipe tuning is measured from the piston face to the center of the convergence cone. Nothing else is valid". Straight from the Master

Scott

My measurement is from the glow plug. Check RCG in classic forum. This engine and the R61F. Very good results on both.

As a practical matter, it really doesn't matter

Use either measurement you please but the best way to set up the system is to first do open face run with fuel/prop to be used. Record the rpm.
Then install the exhaust system longer than the final length will be and shorten the system incrementally until the desired level of "tune" is achieved. As the system is shortened, there should be an increase in rpm, if not, something is wrong.

The desired level of tune will depend on your application. For max rpm the system will usually be somewhat shorter than would be used for general sport flying or for pattern flying since max rpm may not give the best throttle response. Good throttle response through the entire rpm range is necessary for Pattern/sport flying

BTW, I measured from the glow plug. But it doesn't really matter unless you are using the very same pipe/header/plug/fuel combo.