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Oct 10, 2018, 12:17 PM
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Agcat88's Avatar
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H9 P7 ARF and Dirty Birdy ARF Powerplants?


Hi guys, I have a couple of questions that started off of a previous thread talking about engine recommendations for the P7 ARF. I plan on getting one of my P7 and Dirty Birdy ARFs assembled over the winter, but really not sure what engine combination to go with. I already have the Evolution .60NX with the header and pipe combination for the P7. I also have a good stash of NIB Rossi black head 60's with tuned pipes and one NIB AXE 60 I could use. I'm not real familiar with the AXE engines and the performance over the older black heads? It didnt sound like very many liked the Evo set up and was curious as to why?Would there be a big performance gain with using the Rossi engines? My only concerns with using the black head Rossi's would be the extra weight (although maybe minimal) and would require the cowling to be modified a bit for the Rossi's to fit. The Dirty Birdy will for sure get one of the black heads or AXE. Appreciate any input. Thanks.

Brent
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Oct 10, 2018, 12:58 PM
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>>I already have the Evolution .60NX with the header and pipe combination for the P7. I also have a good stash of NIB Rossi black head 60's with tuned pipes and one NIB AXE 60 I could use.<<

I am sure the Evolution .60NX is a good sport engine (I have Evolution gasoline powered 2 stroke engines but not the methanol fuel counter part). However you simply cannot compare the performance, built quality and user friendliness of any Rossi engines. My opinion is definitely bias and I am prejudice. However from over 50 years of experience running all sorts of engines powered by all sorts of fuel I am still enamored with the Rossi's. Mainly the timing on the Rossi's is a lot more beneficial for a heavier pattern plane. The Evolution .60 maybe good for the lighter earlier classics.
Oct 10, 2018, 02:27 PM
DavidsPlanes
doxilia's Avatar
What Hansen said + 1!

Also, AXE Rossi engines are simply later branded and probably slightly redesigned original Rossi's. Note that the Rossi brothers (Cesare & Ugo) parted ways in the late 90's with Ugo (the younger brother) keeping the original Rossi plant and rebranding the engines AXE Rossi. Cesare, the elder brother and original designer of Rossi engines, on the other hand started a new company with his wife Graziosa Barchi which was branded NovaRossi (NR). This latter brand may be much more familiar sounding as they are one of the few glow engine manufactures still producing 2-stroke 60's. In fact, they seem to have catered to our classic pattern needs with recent engine developments and designs. Unfortunately, Cesare recently passed away so there is likely going to be less of a push in R&D at NR although marketing and sales of their engine will continue to be strong and solid as this was something that Ms. Barchi always handled. She is of course now also at the helm of the company.

Whether it be a classic Rossi, AXE or NR, these engines are going to be better suited to classic pattern models like your P7 and DB than the Evolutions. Also, the various Rossi's are all made in Italy with outstanding metallurgy and quality. The Evolution engines are a Chinese brand that compete with various other Chinese brand engines such as Magnum, Thunder Tiger, etc. If you were to take a NR (in particular) and an Evolution engine apart and see how the engines are made and designed, you will be amazed at the quality difference which is also reflected in their weight and performance! I believe all Italian brand 2-stroke "Rossi's" including current production NR's are of true ABC construction something which is quite rare today.

I would prop up a vintage black head Rossi as well as your AXE and put them on the test stand and see how they compare. 11x7 to 11x8 props are likely to work best on them. Depending on your engines' specific geometry, you will have slightly different pipe requirements and exhaust lengths. Tach them and adjust accordingly. Then mount them in your classics and go bore holes in the sky!

BTW, in order to get the models to balance with these heavier engines, it is typical to install the radio battery behind the wing TE former in the fuse. This is particularly true with straight TE or swept wing designs such as the DB and P7, respectively.

David
Oct 10, 2018, 03:26 PM
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Horizion sold there P-7 and recommended the Evo 60 NX, which weighs 17.5 or so oz's......guide a bit lighter than other 60 size power plants. If going with a mainstream pattern 60, does the weight difference become a problem with the C/G? I too have a P-7 and Evo pipe/header, but have held off on getting a 60NX. I'd like to just go with a YS classic. Thoughts. .???

AgCat, have you bench run the 60 NX ? Or Anybody, What are your Thoughts ?
Last edited by mike3976; Oct 10, 2018 at 03:42 PM.
Oct 10, 2018, 05:26 PM
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Quote:
Originally Posted by mike3976
Horizion sold there P-7 and recommended the Evo 60 NX, which weighs 17.5 or so oz's......guide a bit lighter than other 60 size power plants. If going with a mainstream pattern 60, does the weight difference become a problem with the C/G? I too have a P-7 and Evo pipe/header, but have held off on getting a 60NX. I'd like to just go with a YS classic. Thoughts. .???

AgCat, have you bench run the 60 NX ? Or Anybody, What are your Thoughts ?
It is easier to balance a nose heavy plane than a tail heavy plane. Just make sure you have provision to add a little weight on the tail while you are assembling. I typically make up a hatch on the bottom of the fuselage behind the wing trailing edge and put the receiver battery there.
Oct 10, 2018, 05:43 PM
Lipoly Killer
Frank Hurd's Avatar

Rear mounted servos


Use the Rossi and mount the rudder and elevator servo in the rear fuselage.
Oct 10, 2018, 05:57 PM
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Thanks for all the great input so far. Mike3976, I have a 60NX with the Jett Muffler Pipe in an Ultra Sport 40. So far I am real impressed on how the engine runs and pulls. I am running a 10x8 APC prop on it which is the recommended prop with the Jett pipe. It's pulling 15500 static on the ground up at 3900ft field elevation. That 40 sized Ultra Sport is a rocket ship with that engine on the front and a blast to fly!
Oct 10, 2018, 06:00 PM
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Originally Posted by Frank Hurd
Use the Rossi and mount the rudder and elevator servo in the rear fuselage.
So when you say mount the servos in the rear fuse, would you mount them externally at the rear by the tail section?
Oct 10, 2018, 06:06 PM
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Quote:
Originally Posted by Agcat88
So when you say mount the servos in the rear fuse, would you mount them externally at the rear by the tail section?
The P-7 with glass fuselage, does not have an elevator joiner, a forked elevator pushrod is used in original design. There in no room to mount three servos in the tail for elevator and rudder. Beside, you would ruin the classic look of the P-7 with all that external hardware!
Oct 10, 2018, 06:13 PM
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Quote:
Originally Posted by mike3976
The P-7 with glass fuselage, does not have an elevator joiner, a forked elevator pushrod is used in original design. There in no room to mount three servos in the tail for elevator and rudder. Beside, you would ruin the classic look of the P-7 with all that external hardware!
Excellent point! I agree, I would like to keep everything inside the fuse to keep the drag down and clean lines.
Oct 10, 2018, 07:11 PM
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My P7 zooms along quite nicely with an OS 55ax.
Oct 11, 2018, 09:55 AM
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Are the classic black head Rossi 60 and AXE 60 considered short stroke or long stroke engines? Is there a way you can tell if the Rossi's or YS engines are long or short stroke by the numbers and letters on the outside of the case?
Oct 11, 2018, 12:38 PM
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Quote:
Originally Posted by Agcat88
Are the classic black head Rossi 60 and AXE 60 considered short stroke or long stroke engines? Is there a way you can tell if the Rossi's or YS engines are long or short stroke by the numbers and letters on the outside of the case?
Most likely short stroke but it is really easy to figure out by taking off the cylinder head and measure.
Oct 11, 2018, 06:36 PM
DavidsPlanes
doxilia's Avatar
The 60 NX is an over bored 45 size engine. Basically, to get the NX series of engines to be as light as they are, they built them into small crankcases. This is why they weigh considerably less than a “big block” 60 such as the Rossi.

Classics do usually look nicer with internal equipment. I think what was being suggested to counteract the greater weight of a Rossi up front is to locate the tail servos just forward of the wing TE in the rear of the wing saddle/radio bay. The battery however can be installed right behind the TE so one still has access to it.

I forget where Ralph’s scratch build UFO thread is here on the forum but it provides plenty of info on the gear location for CG subject.

David
Oct 11, 2018, 07:15 PM
Registered User
edh13's Avatar
Quote:
Originally Posted by Agcat88
Are the classic black head Rossi 60 and AXE 60 considered short stroke or long stroke engines? Is there a way you can tell if the Rossi's or YS engines are long or short stroke by the numbers and letters on the outside of the case?
All the Rossi's were short stroke. All the round head YS's were short stroke. The square head YS's are long stroke except for the new "classic" currently available. They all have "classic' engraved on the head so you can tell them apart from the old long strokes.
Eric


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