David,

There is a gentleman with a Brushfire at my club. What an amazing flyer! Both him and the Brushfire...

This will be a great offering... no doubt.



jmb52760,

I think an EU-1A is another fine option for the NR...

Brian

Here's my Rossi testbed......from 29 years ago.....kaff....kaff.
Super Scepter....kit by Craft-Air...Rossi RE with 9mm carb/in flight nv, Rohm retracts.
I got a lot of trophys with this airplane....I still have the trophies...and the airplane.
Don might be interested in making this kit...they fly really well.
It is an update of the Deception.
The problem back then as well as now is...to find a straight fuselage for Don.
The pink one is mine...the other one belonged to Richard Verano....note anhedral stab moved higher in the fuse...a big improvement.

Dave

Dave, what did moving the stab up and anhedral help?

Thanks,
Tim

It helped with going to the belly on knife edge...not seen much today....but an incidence change (increase) and c/g adjustment gets the same effect...and is likely the best way to fix it.
In fact...I flew the brown Scepter quite a bit and it flew much better than my straight stab until I added incidence and adjusted the c/g....then mine flew as well or better.
Brian Hebert has a great white paper on trimming called Triangle Trimming....it's very good and easy to understand.
Highly recommended.
In fact....I found that I really didn't know much about trimming an airplane until I actually did it in a couple of moves using TT.
It really improved my F3-A flying ability on the 2mtr electric airplanes.

Dave

I am pretty close to putting my DB in the air. The NR Speed 13 is close to being broke in, I'm just not sure which way leans out the bottom end. I would think screwing it in would lean it but I'm not sure, this is my first NovaRossi. Thanks!

I haven't looked....but in the manual it should say....in is lean...out is fat.

Dave

Thanks Dave. I read the manual and it doesn't address the carb. I went on line and you can't down load the Carb instructions off of the web site.

If the wind is down we're going to fly the NovaRossi tomorrow. I'm still running it rich but the power is there.

Thanks again!

KT

Keith,

that's correct, the engine manuals don't address them because several engines have different carburettor options. This includes the Speed 13 which optionally comes with either the 9 mm or 10 mm carb. There is a general carb manual that describes the settings for each of the carbs that NR makes. I have posted the PDF below. The 9 mm carb (10401) which has an in flight mixture adjustment (two servo control) is somewhat unusual with respect to the high speed needle but otherwise is a standard barrel type carb with idle mixture adjustment which controls the amount of fuel allowed into the barrel. Clockwise turning of the needle, inserts it further into the fuel inlet, while counter clockwise moves it further out. In other words, like Dave said, in is lean, out is rich.

The high speed mixture on the left side is unusual in that the same rotation of the needle screw causes lean or rich results but the mixture adjustment cylinder is counter threaded so the mixture needle assembly is screwed on counter clockwise. If you notice, when you pull the lever rearward, it screws the needle in (lean) while pushing the lever unscrews the needle (rich). This is somewhat counter intuitive in that you'd expect the forward movement of the lever to lean the mixture (same direction as high throttle) while retracting it would richen it - not so.

The 10 mm carb (10405) has no in flight high speed mixture adjustment so its a standard operation carb.

I'll just comment that what might suffer in flight with an engine that hasn't had much fuel yet is the idle. Make sure it is transitioning and holding idle properly before taking off lest you wind up dead stick. Mine started to come into its own after 80 oz of fuel. I can now turn almost any prop and have it idling between 1900 and 2400 rpm depending on the prop. The factory pipe setup is better suited for smaller load props (11x7, 11x8, 12x6). If you load the engine up with more prop (11x9, 11x10, 12x8), the tuning will be a little off and it may not come on the pipe.

I hope this helps,

David

P.S. I added some other documents that you might find useful.

Thank you David. This clears everything up. I have been running it so rich that it was hard for me to tell.

You are so right about the inflight mixture control, it just seems backwards to me but I'm good with it. All of your attachments are very good information, thank you again for those.

I have a little over a half gallon of fuel through it and hope to maybe put 12 oz through it in the morning and try to get her ready to go!

Thank you Thank you.

Keith

I drug my 13 out just now and had a look....you're right....they yak about everything except what we really need to know!
I recall seeing some comments somewhere about where to put the pressure tap into the pipe....it should be just behind the first high point of the pipe.
You can use JB-Weld to hold it in...that stuff can withstand the heat.

Be sure not to run the engine very rich....peak it out then richen it up a tad.
The ABC piston and sleeve hates running rich when new....in fact....if the piston/sleeve is too cold it will prematurely wear the fit of the piston....then when you finally lean it out for max power....it will be down on power because the fit is now too loose.
So....don't be too gentle with it.
I would use 18>20 percent oil containing 20% castor/synthetic and 5>10% nitro.
The mfgr recommended fuel is good and is almost the same I have used previously.

Good Luck tomorrow....I know you will love that engine. I've had a lot of the Rossi RE engines in the past and I cant wait to start up again with the NR engines.
BTW.....the other day I spoke with Sahak who markets the Rossi line of engines....he says that he is getting a lot more engines of all sizes in January.
That should be interesting.....they are all great engines and very similar....availability has always been a problem with Italian engines....although this does not seem to be a problem these days....they are worth any hassle that has to be handled.

Dave

Sure thing Keith.

The factory setting is such that the high speed screw needs to be screwed in 1 to 1-1/2 turns (if memory serves) after some 40 oz of fuel. At half a gallon, you're there. At that point, the mixture lever will start working as expected. With the factory setting, the control seems to not affect the engine much as you are going from pretty rich to slightly less rich and response is not noticeable. At 2/3 of a gallon, you can get her rockin'.

You will also notice that the fuel delivery, and hence the mixture control lever, differs between props not insignificantly. What is lean on a 12x6 is rich on an 11x8. I can max her out with a full forward lever on a 12x6 and then have to pull back 2/3 travel if switching to an 11x7 or 11x8.

Among a few different props I've tested (APC, Rev-Up, Graupner, Xoar & Falcon) my preferred bench prop is the Falcon 11x8. She has yet to fly.

David

This is a good point Dave and it has been referred to NR by the dealers. I have also had some direct contact with NR and have brought some of those issues to light. Hopefully, there will be some documentation revisions in the future.

Indeed. This is another issue with the instructions in that they tell you to run it at low RPM for 30 min. This is the first time I have come across ABC engine instructions telling you to "idle" the engine for break-in. In fact they are not - it is a translation issue. That said, the factory carb setting is adequate for the first 40 oz of fuel or so. So long as the engine is not running cold (i.e., mid to low rpm) initially and is up at operating temps (~12K rpm), the fit of the piston and sleeve should settle while having plenty of fuel. After 40 oz, one can start to loose the white smoke trail. No need to worry, the 40 oz will burn up in no time!

I have been using Omega 10% with 4 oz of castor added. I have also tried pure synthetic Cool Power 10% with slightly higher performance results but the difference is not significant. In any case, the loss of all castor is not a good idea on a high revving ABC engine. NR recommends 10% nitro and 20% 50/50 castor/synthetic (with a 70% balance of methanol). Omega at 17% lubrication is close enough and can be augmented with castor to bring it to 18-20% oil. Sig and PowerMaster also make 50/50 20% oil fuels.

Dave,

what I heard from Sahak is that he will soon be getting Rossi 65's. Others will likely follow. There don't seem to be any plans he's aware of that include the traditional Rossi 61 RE. I inquired specifically about the 3+2. In fairness, NR's designs have come a long way in their 30 years and matching the performance of the Speed/13 will be quite a challenge. Still, I'm curious to compare the Rossi 3+2 as well as the OPS Super (SPA) to the Speed/13 - both of these are rated at ~0.1-0.2 bhp less output. The Speed/13 is putting out about 2.45 bhp @ 18K (extrapolated). The OPS Super is rated at 2.35 bhp.

As a side tidbit of interesting info, Cesare Rossi, the original designer of the venerable Rossi C/L 15, is still at the helm (with his wife) of NR. Axe Rossi (the renamed older Rossi brothers company) is from what I understand now under the managament of Alessandro Rossi - Ugo's (Cesare's younger brother) son. Sadly, Ugo Rossi is no longer with us.

David

Yes....you're right David....Sahak DID say he would be getting the 65's.....Then I asked about other sizes and he said he would try to get them to mfg the 60 RE like this one (5 port SS) that I got from him a couple of years ago.
I guess I had some wishfull thinking a post or so back....heh heh....

Have you heard anything about the new YS?
Anyone have some comparisons to the NR?
After all the hoopla about them I had expected to hear something but I have not.

Back in the late 80's when YS got popular I was reluctant to change from Rossi to the YS....and in fact, the Rossi being a conventional engine was much easer to set up and get running correctly....and keep running corectly.
I and many others ran the YS 60ss successfully back then but I would have been happier to stay with Rossi....they really screamed.

Best

Dave

Is there a preference between the 9mm and 10mm carbs on the NR speed 13 engine? I heard there can be fuel draw issues on the 10mm carb but others say it's not an issue.

Thanks to all for posting great information here. This has clear up all my carb questions. This really is a pretty straight forward carb with the exception of the inflight mixture control...but it works fine once you figure out which way is rich and which way is lean.

I flew the YS motors back in the 80's and to me the only advantage that they had over my Rossi's was the pump. You could put your tank further aft, closer to the cg and still get great fuel flow with out changing the cg. The 80's Rossi was the most powerful engine I had ever run. Now it's cousin the NR Speed 13, should be even better.

I would love to put a pump on the Speed 13 I just don't want to mess with the rear cover and void a warranty.......I really feel like YS would not be in the picture if Rossi would put a pump or have the option of a pump on the Speed 13. Either way I am happy to run the Rossi with or without a pump. One more thing....the price. When you start looking at other engines comparable to the Rossi your looking at close to $200.00 for the engine or more, then add over $100.00 for the pipe and header the Rossi is clearly the best value out there.....I'm just talking money not even about performance.

Better instruction manual, pump or plumbing for a pump and Rossi rules hands down, IMHO.

Keith

Depends on who you talk to.
In the past I have had nothing but trouble with the larger diameter Rossi carbs.
The 9mm carbs have more fuel suction while still enabling the engine to make very nearly the same power.
In addition...the 10mm carbs use a lot more fuel with little power gain.

Another reason is that the 9mm comes with a in-flight nv adjustment which in my opinion makes up for any downside of the 9mm carb.
The in-flight n/v has enough range to it so you will never have to adjust the engine again in the same airplane.

In the end....the 9mm has more advantages than at first glance.

Just a quick thought about the 9 vs the 10mm carb. When I first began flying Webra engines they had the TN carb on them. They were easy to set up and ran consistently. Then the came out with the Dynamix carb...did I spell that right?? The dyna carb was I think a 10mm carb. When you got the Dyna to run it would scream but I never could get them to run consistently so I replaced all of them with TN Carbs. I still have a couple of Dyna carbs if anyone needs them.lol

The 9mm Rossi carb appealed to me because of the inflight fuel mix control. I found this very useful when I flew BVM fan in the 90's. I'm sure the 10mm carb would produce more power but I am looking for reliability so 9mm for me. I am sure others here have more experience and could probably answer the question better.

Keith

Sorry Dave we were replying at the same time.

That's OK Keith....great subject here.

The Dynamix slide carb......WOW.....when set up correctly these were the BEST!
But....I think WEBRA got started off in the USA on the wrong foot.
I think they were being imported by Circus Hobbies (Bill Bennett, Donny Weitz etc)

The Dyna carb on their Speed 60 RE had a HUGE intake and were very difficult to adjust.....I never got it to run correctly.
Then....years later....a local friend asked me to replace the bearings in his WEBRA 40.
It had a Dyna slide carb too....and I knew this engine ran perfectly.
Then I noticed the carb had a much smaller intake.
After nosing around I found out that the 60 RE with the huge carb was supposed to have a Perry backplate pump on it....ie...Circus was selling an engine with the wrong carb.
I bought a 40 size carb and put it on the 60 RE and immediately had an engine that was considerably lighter than the Rossi with every bit as much power.
This version of the Dynamix carb also had the inflight nv.....I use it for years and it is still around somewhere....I still have a bunch of slide carb parts and I still have another 40 slide carb.
I know about the TN carb but I had to have the inflight nv....once I used it I couldnt go back to just a ground adjusted nv.

As an aside....I made a sleeve for the 40 slide carb and installed it in one of my Rossi 60 RE and if course it worked great.

It's all about fuel suction.

Dave

What pushed me to Rossi in the 80's was snapping Webra crank shafts. I can't remember whether they were 17mm or 15mm but I broke 5 or 6 of them before they increased the size of them. By then, factoring in the Dyna carb and the snapping cranks I was done with Webra.

I'm very happy where I'm at now with the Rossi!

Oh yeah.....I remember that now.
It didn't happen to me but I heard about some broken rods that were caused by the piston being too tight at the top when new...
On new true ABC engines like the NR I always take the plug out then put some castor in the cylinder and rotate the shaft with a drill just to give it a head start especially If it is a bit too tight.
Likely with todays CNC mfg the tolerances that can be easily held will make the above nonsense a thing of the past.

Dave

I concur with Dave and Keith with respect to the NR 9 vs 10 mm carbs with the caveat that I haven't tested the 10 mm. I think the 10 mm carb is ideal for engine applications where speed is the goal - i.e., R/C racing. Since I haven't seen it, I'll venture that the Speed/13 venturi version for pure speed events comes with a 10 or 11 mm venturi bore. This is why the engine is rated at 18K rpm because for those events, the engine can potentially reach them.

That said, the 10 mm carb might be better behaved (if it does behave somewhat "peaky") and offer reliable carburation in the presence of a pump. The backplate is an inexpensive part and can be tapped for pressure to feed a Perry pump. The important thing is to insure that the tap does not interfere with the crankpin but it might be advantageous to set the tap on the backplate circumference of the crankpin rotation. This is done on other pump systems (e.g., OS SF-P/RF-P and Hanno as well as the 46 SF/VF's)) as well as others that I have seen. A center tap might be the better way to go - only testing will tell us.

Other than wanting to gain 200-300 rpm perhaps from the 10 mm carb, I feel the 9 mm is an overall better choice for pattern classics. Like Dave said, simpler to operate, more reliable fuel draw and the mixture adjustment is very convenient. I'll add that not having to get one's fingers close to an 11" prop that might be close to 15K to find optimum rpm is a nice bonus too.

On a separate but related topic to in-flight mixture adjustments, I just checked the standard OPS 8.5 mm slide carb (somewhat similar to the Dynamix in design except the spray bar is still within the intake rather than on the side) and the high speed needle and adjustment lever are a single part. They can't be adjusted independently as one can on the NR. The needle screws on to the carb in a typical clockwise fashion (unlike the NR) until it reaches fully closed. The threads on the needle and carb are such that the action of pulling back on the lever results in the needle being "opened" a substantial amount compared to a thin thread as one might find on a SuperTigre Mag carb. In order to get the lever positioned correctly for the servo pushrod, the needle must be rotated to the correct position upon being thread on; otherwise it ends up putting the lever in an awkward position (i.e., on top of the carb). A nice feature of this carb is that all that's needed for inflight mixture is the different needle and a spray bar replacement with the coarser threads. In short though, the servo direction for lean/rich on this carb is opposite that of the NR 9 mm carb.

I eventually hope to test the NR, Rossi 3+2 and OPS with 10 and 11 mm carbs including the Dynamix using a Perry pump and tapped backplates (assuming I can source spare backplates).

Dave, curiously, a Speed 40 Dynamix carb came with a Speed 32 that I purchased (same intake bore). The throat portion of the carb that inserts into the engine is narrower than that of the 40 so its technically not the same carb. I'll eventually be comparing performance of a TNII and the Dynamix on a Webra Speed 36 that will go into a 30 size Tipo.

David

Keith, use the bladder tank and put it on the CG, you'll be fine. Jett tanks aren't bad on the price but the cost of memebership (the syringe) is a bit high. You could go to the feed store and get a syringe from them to see if you're going to like it (some hobby shops sell them too).

The only concern you'll have is that since it's now over the wing it's going to be higher than your carb and with an RE you'll have to make sure you have the room to run the exhaust out over the tank.

Tim

Keith,

by the way, the answer to your RCG question above on the related thread is in post #24 here... I designed this plane specifically with the new RE offerings on the market today in mind.

Will,

thanks for your kind comments and interest in the Brushfire re-design. I do indeed expect it to loose 8 oz at the very least. My goal is for it to be ready to fly at 7.5 lbs with an additional pound of fuel for an 8.5 lb model on takeoff. I've been concerned with the weight factor to the point where I'm now thinking I have to reinforce the front end for the monster power RE engines available today. I'm thinking something simple like what was often done with the engine mounting in MK kits where two of the formers are tied together with HW beams which in turn extend into the cowl area to mount the engine on. In my case, I'll simply tie two of the formers together with 1/8 or 3/16" ply rails. The engines will be mounted on radial mounts.

I should mention that my re-design included a slight scale up of the model as well as plug-in wings. The model is 60.5" long and has a span of 66.5". This scaling puts the plug in wing panels at the spec 858 squares of the original. Out of curiosity, what are you thinking in terms of span for the Jett 120? It seems that no matter how big I make them, you need them bigger! Maybe you should put that Jett into the MK Chipmunk...

I'm continuing with development and many subtle changes as my thinking of it evolves. One thing is certain though - I specifically want this to be a wood built fuse as it will offer several conveniences that I feel would be hard to achieve with a shell type fuse such as one made of glass. Otherwise, I wouldn't have bothered with it. I'll have some further news on it before years end.

David

Yep.....I see those huge syringes at the local feed store as well....A lot of the control line guys use them to fill their fuel tanks.
Recently I got a couple of bags of small syringes to use as glue applicators. These are stupid cheap. I think there were 4 in a bag for a couple of bucks.
They came in really handy using Elmers Carpenter glue while building my Dirty Birdie wing and stab.

Dave

Hi David,
Some 'food for thought' regarding the front end of the Brushfire and possible reinforcement: use a Hyde mount. The structural requirements are surprisingly minimal - probably just an 1/8" ply firewall for a .60. There has been a great deal written on the subject, but an email to Merle Hyde would provide definitive clarification. The MK solution works well, also, but is a bit heavier.
Back in the early '80s, a couple of my fellow club members built Brushfires from the original plans. All wood, all paint about 9.5lbs finished with Rossi 60s. They flew very well.
Please keep us posted with your progress.
Will
ps I also have plans for a 120 sized Arrow, another good choice for the Jett