Ralph White

I would like to start this thread to discuss and compare results on the NovaRossi R61F and the R61F Speed/13 engines.

My son, Nick, has been running the R61F Speed/13 in the GP's ARf Dirty Birdy. I have just installed the R61F in my old Fliteglas Models Saturn from the 70's.

Nick's Dirty Birdy is a great flying plane and the Speed/13 goes like gang busters. Been clocked on radar at 147 mph out of a dive. My Saturn had an OPS 60 in it but the OPS is getting a little weak from age.

Hopefully we can get some discussion going on things like: rpm, tuned pipes, pipe pressure fitting location, props, fuel, glow plugs, etc...

I'm ready to put the pipe pressure fitting on my Saturn's pipe. What is the correct location on the NovaRossi 50400 Long Pipe? I saw a picture of one with the presssre fitting back quit a distance from the high point of the front cone. I was told on other pipes that the fitting should be at the end of the front cone (largest dia.). Any body have an opinion on the location?

Please don't let this thread get into arguments on items. Let's just tell everybody how we are doing things and what the results seem to be.

Ralph White
Neoga, IL

countilaw

Ralph,
I don't use a pipe now, but back in the 70s and 80s when I did, we always put the pressure nipple right in the largest part of the pipe. Now I am not pressure or exhaust engineer, but it had something to do with the pulses of pressure that traveled down the pipe and back to the cylinder. And the pulse pressure at the largest part of the pipe, arrived and pressurized the tank at the crucial time for the timing of the engine.

That is what I remember from back then.

Frank

RC YEAGER

Hi Ralph:

I used to fly a Saturn back here in Puerto Rico back in 1978-1980. I think it was one of your Fliteglass kits too... Anyway... I did it the same way Frank describes. Worked well for me. Can't give you any recent experience since I'm returning to RC after a 30 year absence.

Luis

PatternPilot

My Feedback: (58)

Pressure tap , just in front of the first baffle of the pipe ( from front of pipe )

Pylonracr

Macs products, maker of many tuned pipes, says to put the pressure tap either at the largest point on the pipe or on the header very near the exhaust port. I have used both and can not tell the difference. Both work for me, and I run a tuned pipe on almost everything I fly now.

RC YEAGER

That is great to know... Hated dealing with securing the plumbing way over to the widest part of the pipe... I'll try the header on my two ongoing projects

Pylonracr

After reading the original post again, I may have a little more information to contribute. I bought a 61 Speed13 for a fast airplane scratch build project. I built the plane around the engine. After some initial problems with a machining error in the carb, the engine is a powerhouse. I got the 10mm carb option since I wanted top speed. This airplane has the engine mounted upright, and with the header in place I can not get the tank high enough. Mine has fuel draw problems. The obvious solution is to side mount the engine, or use the smaller 9mm carb which would be a better choice for a pattern plane. I put a pump on mine, which also works. The next plane I build around this engine will be side mounted.

I have about a half gallon of break in fuel through mine.
10 to 15% fuel is fine. I would not use less than 20% oil, but that goes for all of my engines.
Novarossi says use only their C6S glow plugs or you void the warranty. They work fine so I use them.
The 50400 pipe is very quiet, but good god is it heavy!! When I weighed one (a while ago) I think it was 5 or 6 Ounces! Yikes. I made a carbon fiber pipe for mine, but I think a Macs quiet pipe will work at half the weight.

I am setting mine up to run in the 17K range, but other projects have been pushed in front of this one so I don't remember what props I was using. Since I am going for speed, they are small diameter and high pitch. I will dig out my notes if anyone is interested.

Leo at Klasskotemo and Allen at Planethobby are the experts on these things, they sell them and will help with any questions or problems. Great people to work with.

Scott

doxilia

My Feedback: (3)

Scott,

there have been others who confirmed that the 10 mm carb on this engine does not have enough suction to draw fuel consistently unless the carb/tank relationship is finely tuned beforehand on a stand and then matched in the model. The obvious and best solution with that carb is to pump it like you have.

That said, given you are running it in a speed model, I suspect you are probably using a straight or angled header rather than a fuse top style header. Given the low exhaust port location of the Speed/13, the mid-line of your tank is probably quite a bit below where it should be. Two solutions to this: 1) use a the low rise 1" fuse top header (or higher) and 2) use a shallow draft fuel tank where the fuel is distributed sideways rather then height wise. Tanks like the Hayes 12 and 16 oz slim (you'll probably want a 16 if you're aiming for max RPM) work well as others of similar geometry. A long cylindrical tank such as the Sullivan 16 oz "shampoo bottle" tank also work well although there is a longer fuel draw. This latter might suit your model better as it is likely narrow. Several folks have used this engine/9 mm carb/tank combination in the GP Dirty Birdy ARF albeit with the tank mounted sideways.

I haven't tried the engine side mounted but others have with good results but a similar carb/tank relationship is still required. I suspect it is harder to design an effective speed plane around a side mounted engine though. The advantage of the 9 mm carb is that it allows you to meter the fuel in flight as the fuel level changes and this helps too but you want get max RPM out of the engine. IMO, the 9 mm is best suited to pattern while the 10 mm to speed.

I'd be interested in hearing what pump you're using and how you have it installed.

Omega 10% fuel with 3 oz of castor added (to bring it to ~20% oil content) has worked well for me - with pattern. For speed, I'd likely try Omega 15% nitro 4-stroke 17% 50/50 oil blend.

The Speed/13 is a generally heavy engine setup as the engine itself is heavy too (~620 g). Model weight should be adjusted accordingly. I tried using a current Macs 10 cc QP but wasn't pleased with the results. I believe the pipe doesn't allow the engine to breathe properly. The NR pipe works much better on a 9 mm carb and I suspect even more so on the 10 mm. However, there are other wider bore pipes which allow the engine even better performance than the 50400. The old Macs flat back 10 cc pipes work well as reported by Robert on the RCG classic forum. I suspect an OPS 10 cc pipe works equally well and perhaps better than the NR. I will try one this Spring.

That would be great. I'd be interested in hearing its performance on 10" (9"?) props as the smallest prop I considered was a wood 11x7 (again, for pattern). Max engine power should be just about at 17-18K and I imagine you would get there on the 10 mm and 15% nitro on a light 9x9, 9x10,10x7 or thereabouts.

Power of the engine on a 9x10@17K would be approaching 2.30 bhp. On a 10x7@17K, 2.46 bhp which is just about peak performance. It's just a matter of finding out how to get the engine there...

David

doxilia

My Feedback: (3)

Ralph and others,

here is my much abridged review of the stock engine/exhaust configuration published in the April 2014 issue of FlyRC.

Comments most welcome.

Enjoy!

David

RC YEAGER

Scott, David... Great info... I plam to buy one of the NR with the 9mm carb in near future... Already bought one of the small 09.20C for a Tweedy Bird (.21-.25 Dirty Birdy) I'm building... Haven't broken it yet, but it easily the heaviest .21 size engine Ive ever handled...

RC YEAGER

That review will help me a ton... Txs David...

Pylonracr

David
I run the new Perry pump which I believe is the Cline. I was kind of on my own here. I bought the engine from Leo at Klasskote and built the plane around it as I stated earlier. When the plane was nearing completion I put the engine on my test stand to break it in. It would not draw fuel past half throttle. I emailed Leo, who informed me he was no longer a dealer as Novarossi decided to have only 1 US dealer, SMT distributing. I contacted them and when they found out I bought the engine from someone other than them they told me to go to hell. Wonderfull customer service there.

Leo and Allen at Planethobby sent me a carb, since mine had a machining error from the factory causing my problems. Without them I would have a really cool looking paperweight. They would not even allow me to reimburse them for their cost.

I run carbon fiber pipes, so you may have to try a few stock pipes or make one. The 50400 pipe runs well, but I can't justify the weight.
I am pretty sure I was running a 10*9 on the bench, but I will have to check to be sure.

Scott

doxilia

My Feedback: (3)

Scott,

good to know. I might pick one up to give it a try on the 10 mm.

Wow! Were you really able to get the engine to 17K on a 10x9 and 15%? That would be impressive considering the engine would be producing about 3.16 bhp (per my article). Your RPM's must be more in the range of ~15.5K, yes?

David

doxilia

My Feedback: (3)

Luis,

Glad to be of help.

Saludos, David

Pylonracr

David
I just pulled the prop off of my Speed13. It is one of my hand carved 10.25x8.5. I ran several props on the engine, once I got it running, and kept all of them in the 17k range. I will have to check my run notes to see what other props I ran it on. By the way, I am at 5000' altitude.

Do us all a favor and don't quote horsepower, as it is a completely useless arbitrary number that at one time was supposed to represent how much torque could be applied in a given time frame. It did not represent any meaningful figure then, and does not represent any meaningful figure now.

Scott

doxilia

My Feedback: (3)

Luis,

you won't be disappointed with this engine!

I'd love to see that build as I'm a big fan of the 25-32 size classics. Please do post some snaps on a thread or send me some pics!

I'd also be interested in hearing how the 09.20C performs as I have one too waiting for some worthy project.

David

doxilia

My Feedback: (3)

Scott,

I'd be interested in your figures; please do post pipe exhaust length (and ideally geometry), prop, plug, fuel and RPM when you locate them. I'll assume your tests were all done at 5000' elevation in "good weather"...

I tend to agree with you that horsepower is not a very useful measure of an engines performance - particularly in light of the fact that the units date back to the late 1700's (when no other than Mr. Watt himself coined it). Dynamometer output would be of more interest as it is a direct measurement of both torque and RPM but those figures are hard to come by and in particular for this engine (I made a request to Mrs. Rossi to see them). Personally I feel that all measurements of power should be expressed in Watts but curiously, more than 200 years later, many folks don't have a feeling for that unit especially in the context of 2s glow engines. With the electric folks one can talk about 1000W or 1500W of power for a given airframe but translating that in one's head to the equivalent "horsepower" for a glow engine is typically not within the grasp of most folks. Because of this I have found it useful to discuss BHP as a proxy for engine performance.

That said, the BHP numbers I was mentioning were not being quoted but rather computed from the derivation of an equation involving only prop geometry and RPM. The fairly simple formula is remarkably consistent with the numbers resulting from dyno output. According to NR, this engine has a maximum power output at ~18K RPM.

David

Pylonracr

David and all
It seems that I am going to be of less value than I had planned. My Novarossi notebook has grown legs from my office, so this is all going to be off of memory.
The fuel is my usual break in blend: 15.5% nitro, 22% oil (80/20) and the balance methanol. After a gallon, my run fuel will be the same with 20% oil.
The plug is a C6S.
The pipe is tuned to a sonic tuning length of 16". That may change, but not by very much.
My pipe is carbon fiber. It weighs 29.5 grams. It is unmuffled, and the rest of the details I am keeping close to the vest. I have an insane amount of time and money invested in my pipes, and plan on keeping them to myself. You are correct in stating this engine is picky about pipes, but with some research you can find one that works. The 50400 pipe is very quiet and works well, but I just can not bolt that brick to my plane.
Your statement about fuel tanks is kind of a dream. There is room in this plane for 10oz of fuel between 2 tanks. I wasn't kidding when I said I built this plane around the engine.
The plane has not flown yet, so all of my running has been on the test bench. I put the engine in the plane after I got it running to my satisfaction. The engine has one of my hand carved 10.25x8.5 props on it, and in the cradle was a 9.75x8.5 prop. I carved these props for another speed plane, and the interesting thing is both of these props have almost the exact same shaft load. The 10.25 prop has narrower blades. I made these props to get more disc area and maintain rpm, so the engine will turn both of these props within 100 rpm's. The load on the engine with either of these is probably slightly less than a 10x8 sport prop.
All running was done at 4850 altitude in "good weather" whatever that is.
If I manage to locate the notebook I will elaborate, if not I will have more info when I finish my current project and bring this one back to the workbench. An hours work and it will be ready to fly.

Scott

Ralph White

Hello everyone, This thread is really looking good. It's exactly what I was hoping for as supplying info about the NovaRossi R61F and R61F Speed/13. Thanks to everyone for your posts. Nice review on the Speed/13 David.

I have received the pressure fittings for the tune pipe. I think I will go with placing the fittings at the high point of the 50400 pipe. I agree that the 50400 is a little heavy but I'm going to give it a try for now. Will be using an APC 11 x 7 prop for break-in on the R61F. Will probably use the 11 x 7 for flying as well. That is the prop we have been using on Nick's R61F Speed/13. I will get some rpm numbers posted as soon as I get it going. I will be using the 9mm carb. 10mm carb is in the picture below.
Ralph White

dphill2

My Feedback: (1)

[QUOTE=Pylonracr;12003531]David
I run the new Perry pump which I believe is the Cline. I was kind of on my own here. I bought the engine from Leo at Klasskote and built the plane around it as I stated earlier. When the plane was nearing completion I put the engine on my test stand to break it in. It would not draw fuel past half throttle. I emailed Leo, who informed me he was no longer a dealer as Novarossi decided to have only 1 US dealer, SMT distributing. I contacted them and when they found out I bought the engine from someone other than them they told me to go to hell. Wonderfull customer service there.


Ralph, I just wanted to say a few words about your thread as I've been reading the comments as I too enjoy flying the Nova Rossi Speed 13 ! When you started this thread you ask that people refrain from starting an argument !! After reading the quote from Scott ( Pylonracr) I just had to respond .. Buddy the owner of SMT is a friend of mine and I tried to help him when he started up his business, to this day, I have never heard him ever tell a customer to go to hell !! I just wonder what Scott ask Buddy for him to say "go to hell" As a matter of fact, he would try his best to help any one no matter where they got there Engine. I'm sure if you check his web site you will find a complete listing of NovaRossi Engines & Parts. at a very good price. The Speed 13 is 199.00. Just for your info.. Not trying to start an argument, just trying to set the record straight...
Keep up the good work Ralph and tell Nick I said Hello !!!

Dave..

Pylonracr

Dave
I thought about it for a while before I posted on this thread just because of the original post. I decided stating the facts was important, and I did not try to start a argument. As for your question, my contact with SMT was through email, so I have no idea who I was in contact with. I sent a very detailed email with the problem I was having and everything I had tried to cure it, and that it would not draw fuel over half throttle. They responded fairly quickly wanting to know when I purchased it, so I told them where and when. I got a response back almost immediatly telling me that if it is too lean, open the high speed needle 1/2 turn and it will richen it up, and use 10% fuel with at least 16% oil. None of my emails after that were answered.

Leo and Allen stepped up to the plate and helped me by sending me the part I needed at their own expense.

Not trying to start an argument, just setting the record straight. Maybe they help other people, but they did not help me.

Scott.

To the original poster, if I have steped on your toes, or you don't like my post please pm me and I will leave the thread with no hard feelings.

dphill2

My Feedback: (1)

Scott,
I only felt it was a bit unfair to say Buddy told you to Go to Hell, as I've said I known him for a long time and
spent a lot of time in the shop and have never heard him talk to a customer like that . The data you have come up with is great and I'm sure it will help the guys that
fly Nova Rossi products where ever they buy em.. Keep up the good work !
PS. Hello Doxilia, haven't talked with you in a long time, I see your still at it !!

Dave

RC YEAGER

"I'd love to see that build as I'm a big fan of the 25-32 size classics. Please do post some snaps on a thread or send me some pics! I'd also be interested in hearing how the 09.20C performs as I have one too waiting for some worthy project."

Of course David. I think the correct thing to do is start a new thread so as not to hijack Ralph's thread. Not sure about it being a build thread since I'm making a comeback after a 30 year hiatus (although I joined RCU and made like 10 or so flights in 2005) and haven't built in at least that amount of years. Maybe a sorta "various stages of completion" thread, with some insights. I'll do it in a few days.

Ralph White

Here's Nick's Dirty Birdy with the NovaRossi R61F Speed/13 getting it on. Radar checked 147 mph https://www.facebook.com/video.php?v...325682&theater

Pylonracr

One more thing to keep in mind for everyone planning on using an R61 on a classic pattern plane. The engines available when classic pattern planes were abundant were quite light compared to the Novarossi. I kind of touched on this earlier, and so did Doxillia. If you are building for this engine, start early by placing components in the plane for balance. Plan on moving weight back to compensate. Building a hatch behind the wing of a plane under construction is easier than waiting untill it is painted and filling the tail with lead.

Scott