Suggestions for Dirty Birdy Engine

[Jimmy Russell]

Soon I'm going to be starting to build the Bluejay Dirty Birdy kit I won at Knoxville.  I have been wanting to build a plane specific for SPA.  My Killer Kaos is great but it has retracts and that NovaRossi is craving a tuned pipe.  So I'm gonna build the DB with fixed trike gear and try to keep it light.  I'm leaning toward a 2 stroke due to prop clearance with trike gear.

Novarossi R60f: kinda heavy and I really don't like the funny adapter to mount a muffler, it leaks on my Killer Kaos.
Find an old OS 61 SF:  matches the plane and many think one of the best 2 strokes ever made.
OS 55 AX:  Light and pretty powerfull
OS 65 AX: but it's a little heavy I think.

OS 91 or 95 4 stroke:  13" props 

Thanks guys,
Jimmy

[Bernie & Jude Olson]

I recommend the OS .65 for the Dirty Birdy because of the added power over the .55.  Each of those engines power three or four of my SPA planes and the bigger engine clearly provides more pull in the vertical maneuvers.  A lot of the guys have had problems with the bearings on the .65.  I also had to replace the bearings on one of mine with a set from Boca this winter which breathed new life into the engine.  The .65s seem to have more vibration than the .55s which I haven’t been able to solve.  Guess it just has heavier junk flinging about.  My current build, a Dirty Birdy, is getting an OS .65.

 

I’ve only got one SPA plane with the OS .95.  Its best attribute is that it sounds so much better.  The engine has a lot of torque but I’m still learning how to run it.  You’re right that the prop clearance is an important concern.  A lot of the SPA East flyers seem to run this engine.

 

I haven’t run a Rossi but some of the guys who do really speak well of the engine.

 

 

Bernie

Texas

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[Duane Wilson]

Jimmy;

 

Most of my planes over the past few years have been “trikes”.  I have used the .91 or .95 FS in all of them, and as long as your landing is reasonable, the prop will be OK. I did have problems with several “unreasonable” landings in Knoxville this year due to unpredictable winds, (and maybe a smidge of pilot error), but it’s worth it IMO to have that OS 4-stroke in the front.  Note the Fults LG.  They are heavier than a standard nose wheel, but they save a lot of airplane damage in case of “unreasonable” landings.  I have 1 to 1-1/2 inches of clearance and it takes a pretty bad landing to use up that clearance.

 

Duane Wilson

6 New Cross South

Asheville, NC 28805

(828)777-0841

 

 

 

 

From: spame...@googlegroups.com [mailto:spame...@googlegroups.com] On Behalf Of Jimmy Russell
Sent: Thursday, June 16, 2016 9:18 AM
To: The Senior Pattern Association <SPAme...@googlegroups.com>
Subject: [SPA] Suggestions for Dirty Birdy Engine

 

Soon I'm going to be starting to build the Bluejay Dirty Birdy kit I won at Knoxville.  I have been wanting to build a plane specific for SPA.  My Killer Kaos is great but it has retracts and that NovaRossi is craving a tuned pipe.  So I'm gonna build the DB with fixed trike gear and try to keep it light.  I'm leaning toward a 2 stroke due to prop clearance with trike gear.

--

[Jim Johns]

Jimmy,

I have a Bluejay DB I'm building with a 2-stroke. I started it before I flew an OS 4-stroke. I test flew one of my older Daddy Rabbits with an OS 61SF in place of the usual 91 Surpass. Absolutely no comparison - the 4-stroke wins hands down. Therefore, I'd vote for a 91/95 4-stroke. Bend up some longer gear if you are worried about prop clearance. 

Build it with trike gear if you like, but mine will be a taildragger. I prefer a taildragger for simplicity - nose gear always seems "fiddly" to me. Our field is grass which is easier with a taildragger. If you build it with trikes, spring for an extra micro servo like a Hitec HS81 and a separate channel for steering. It's simple to set up a mix and makes centering a snap. 

Jim

Sent from my iPhone 6S

--

[chue...@comcast.net]

Hi, Jimmy,

First, congratulations on your SPA success!  As for an engine for you DB, I used a NovaRossi R60F with a Jett muffler.  This combo gave me unlimited vertical and I was able to fly the entire Advanced schedule without running out of fuel using the stock tank.  This was the ARF, which was heavier than you BlueJay kit will be.  Plus. these NR engines are on sale now for about $130.00 -- can't get much less expensive than that for a powerhouse engine.  The Jett is about $85.00, so you are still in at a good price.

Phil Spelt, KCRC Emeritus
AMA 1294, Scientific Leader Member
SPA L-18, Board Member
Oliver Springs, TN  (865) 435-1476v  (865) 604-0541c

---

[jfowe...@gmail.com]

Jimmy,

   It basically comes down to what style of flying you like. There are lots of opinions - pro or con - about the 2-stroke versus 4-stroke choice. A while back I tried a 55 AX, a 91 4-stroke, and then a 61 SF in the same airframe (a Compensator) that weighed about 7 1/4 lbs more or less depending on the engine. That was too much for the 55AX flying in the Expert class with some maneuvers that required strong vertical performance. The 91 pulled great, but I had trouble getting consistent runs. I tried two of them. Even engine expert Bill Collins couldn't find what was wrong. Then I tried the SF and the world suddenly became a much happier place. I love the simplicity of the 2-strokes and I also prefer how they fly since that is what I grew up with. Others like the 4-strokes and that's their choice. I really won't argue either way. It just depends on what you like.
   The SFs are available at swap meets and on the internet, but they haven't been made since 1996. They are almost the same weight as the 91 4-stroke and have the same bolt hole pattern. Thus, don't let weight be the deciding factor between a 65AX and 61SF - you won't save weight with the SF.. I like Bernie's suggestion of using a 65AX as it is in current production. The downside is that you will have to replace the bearings - but that happens eventually on all engines, so don't worry about it. The Rossi is a great engine too - you just have to get the right muffler and adaptor.

Jeff

[Steve Ehlers]

Jimmy ,
I will echo Jeff's and Bernie's analogies ,with a couple caveats .I too have and use the 61 SF's. ,but you have to be Very careful about buying these as used engines.OS had a coating problem with the liners and you are no longer able to buy replacements .The engine weights in comparison to the 65 is that it weighs approximately 3 Oz's more. Given the fact that I own 6 SF's Nib and 2 completely rebuilt and  with new pistons and liners , I'm not jumping ship ,at least yet....You can't beat a new 65 for pure simplistic grunt with just a stock muffler,
but don't use OS recommended prop sizes for it. Also change the bearings right off the bat or quickly after break in .
The bearings are JUNK that come with it. OS hobby services denied my brothers claim when the rear Bearing cage exploded after less than 6 runs and less than a gallon of fuel .The claimed Rust caused the failure and would not repair or replace.So much for a 2 year warrantee they claim to have which is too bad.
My next new engine to use other than the SF will be a Nova Rossi ,partially for that reason. 

[Jimmy Russell]

Thanks for the info guys!  I appreciate the first hand experience SPA members are so willing to share.  I have the NR R60F with the adapter and the NR X tuned muffler on my Killer Kaos.  It is a great engine.  It just leaks around the adapter.  I may try to take the gaskets off and see if that helps.  I agree it is powerhouse.  It will pull my close to 7lb Killer vertical and drags that plane pretty fast especially with the gear up.  I guess the 55 is off the list.  I don't want to trade a couple ounces for power, when these large 60 size airframes have a lot of surface area to drag thru the air.  Bearings aren't a big deal.  I can change them no problem.

[Patternpilot One]

Jimmy,

Look at the Jett muffler for the NR.. they claim the os muffler and Jett will attach without any off set adapter.

S.

Sent from my Verizon Wireless 4G LTE smartphone

-------- Original message --------
From: Jimmy Russell <jameslela...@gmail.com>
Date: 06/16/2016 1:18 PM (GMT-05:00)
To: The Senior Pattern Association <SPAme...@googlegroups.com>

[chue...@comcast.net]

I don't know who the "they" is, but I needed the NR adapter for the Jett tuned muffler I am using.

Phil Spelt, KCRC Emeritus
AMA 1294, Scientific Leader Member
SPA L-18, Board Member
Oliver Springs, TN  (865) 435-1476v  (865) 604-0541c

---

[Jimmy Russell]

The NR R60F has a 3 bolt round exhaust port like the old Rossi's.  Out of the box they come with a manifold screwed to these 3 tapped holes in the block.  This manifold has a round tube for fitting the NovaRossi header which is fastened with a spring wrapped around the cyl.  For use with a standard 2 bolt muffler they sell an adapter.  It bolts to the 3 holes in the block and has 2 counterbored holes for mounting a standard 42mm bolt centers muffler.  It's obviously an afterthought as you have to remove the carb to get to the forward muffler bolt.

On the other hand the model CR NovaRossi's have the standard rectangular exhaust port with standard OS bolt spacing.  These CR engines are more pricey than the R**F models.  They use a short plug too.  I think it stands for Cesare Rossi, maybe one of the Rossi Brothers?

I think the R60F and Speed13 versions are the "REX" brand of NovaRossi.  My engine came with "REX" stickers and markings in the box.

I hope I described this clear.  I'll take a pic of my R60F with adapter and the NR muffler on my Killer later.

[Ddphill9]

The 3 screw adapter will accept a stock 744 OS muffler and works fine !!  When you order a Jett muffler order the one that fits a OS SF and it will bolt right on !!  You can also order a CR 60 F  that has a standard ex port and any OS muffler will bolt right to the block with out any adapter !!

The pictures is a R60 F with the adapter that comes with the motor and the OS muffler bolted on !!  Works great !!!

 

Dave

  

 

ddph...@aol.com

[chue...@comcast.net]

Jimmy,  Your description sounds just like my NR -- round port, 3-bolt adapter, etc.  I didn't have to remove the carb to install the Jett muffler, but did have to buy the adapter.

[Patternpilot One]

Dave,

My R60f did not come with the adapter, so I will order one. I already have the Jett to fit OS.. the question is mine engine came with the 9mm in flight mixture carb. Should I use this one or get the 10mm carb ?

Scott A.

Sent from my Verizon Wireless 4G LTE smartphone

-------- Original message --------
From: 'Ddphill9' via The Senior Pattern Association <SPAme...@googlegroups.com>
Date: 06/16/2016 10:37 PM (GMT-05:00)
To: SPAme...@googlegroups.com
Subject: Re: [SPA] Re: Suggestions for Dirty Birdy Engine

The 3 screw adapter will accept a stock 744 OS muffler and works fine !!  When you order a Jett muffler order the one that fits a OS SF and it will bolt right on !!  You can also order a CR 60 F  that has a standard ex port and any OS muffler will bolt right to the block with out any adapter !!

The pictures is a R60 F with the adapter that comes with the motor and the OS muffler bolted on !!  Works great !!!

 

Dave

  

 

ddph...@aol.com

 

 

-----Original Message-----
From: chuenkan <chue...@comcast.net>
To: Discussion, SPA <SPAme...@googlegroups.com>
Sent: Thu, Jun 16, 2016 2:33 pm

[Greg Kieliszek]

Not a fan of the OS .65 since mine blew out the bearings with probably less than 50 flights.

 

Greg

[Greg Kieliszek]

Great looking airplane Duane!

 

Greg

 

From: spame...@googlegroups.com [mailto:spame...@googlegroups.com] On Behalf Of Duane Wilson

Sent: Thursday, June 16, 2016 9:37 AM
To: SPAme...@googlegroups.com

[Greg Kieliszek]

My 9# (dry) Deception has the Rossi .60 up front and I couldn’t ask for better vertical strength running a 12/7 APC and 5% fuel.

 

Greg

[Greg Kieliszek]

Bearings can be a “big-deal”. Me and Jim Johns, and Russ Chiles were unable to extract the bad bearings from my OS 65AX.

 

Greg

 

From: spame...@googlegroups.com [mailto:spame...@googlegroups.com] On Behalf Of Jimmy Russell

Sent: Thursday, June 16, 2016 1:18 PM
To: The Senior Pattern Association <SPAme...@googlegroups.com>

[Larry Hill]

Well guys the DB with a magnum 91  4 stroke  and a13/8 APC prop is about as good a combo as money can buy . Some 2 1/4 wheels can be added and give a little extra clearance if needed .  I had a couple (ARF DB from tower) this was a great combo and a great flying plane , but the construction mainly the fuselage was very weak. Could almost crash it's self in mid air.  L Hill

On June 17, 2016, at 8:15 AM, Greg Kieliszek <gkiel...@nc.rr.com> wrote:

My 9# (dry) Deception has the Rossi .60 up front and I couldn’t ask for better vertical strength running a 12/7 APC and 5% fuel.

 

Greg

 

From: spame...@googlegroups.com [mailto:spame...@googlegroups.com] On Behalf Of Jim Johns

Sent: Thursday, June 16, 2016 10:27 AM
To: SPAme...@googlegroups.com
Subject: Re: [SPA] Suggestions for Dirty Birdy Engine

 

Jimmy,

 

I have a Bluejay DB I'm building with a 2-stroke. I started it before I flew an OS 4-stroke. I test flew one of my older Daddy Rabbits with an OS 61SF in place of the usual 91 Surpass. Absolutely no comparison - the 4-stroke wins hands down. Therefore, I'd vote for a 91/95 4-stroke. Bend up some longer gear if you are worried about prop clearance. 

 

Build it with trike gear if you like, but mine will be a taildragger. I prefer a taildragger for simplicity - nose gear always seems "fiddly" to me. Our field is grass which is easier with a taildragger. If you build it with trikes, spring for an extra micro servo like a Hitec HS81 and a separate channel for steering. It's simple to set up a mix and makes centering a snap. 

 

Jim

Sent from my iPhone 6S

On Jun 16, 2016, at 8:18 AM, Jimmy Russell <jameslela...@gmail.com> wrote:

Soon I'm going to be starting to build the Bluejay Dirty Birdy kit I won at Knoxville.  I have been wanting to build a plane specific for SPA.  My Killer Kaos is great but it has retracts and that NovaRossi is craving a tuned pipe.  So I'm gonna build the DB with fixed trike gear and try to keep it light.  I'm leaning toward a 2 stroke due to prop clearance with trike gear.

Novarossi R60f: kinda heavy and I really don't like the funny adapter to mount a muffler, it leaks on my Killer Kaos.
Find an old OS 61 SF:  matches the plane and many think one of the best 2 strokes ever made.
OS 55 AX:  Light and pretty powerfull
OS 65 AX: but it's a little heavy I think.

OS 91 or 95 4 stroke:  13" props 

Thanks guys,
Jimmy

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[Jamie]

There are several Jett mufflers for many different 2 stroke motors. Talk to Dubb to get the one tuned for your purpose, if you want the best performance out of your engine.  

Jamie

Prattville, Alabama

On Jun 17, 2016, at 7:16 AM, Patternpilot One <patter...@hotmail.com> wrote:

Dave,

My R60f did not come with the adapter, so I will order one. I already have the Jett to fit OS.. the question is mine engine came with the 9mm in flight mixture carb. Should I use this one or get the 10mm carb ?

Scott A.

Sent from my Verizon Wireless 4G LTE smartphone

-------- Original message --------
From: 'Ddphill9' via The Senior Pattern Association <SPAme...@googlegroups.com>
Date: 06/16/2016 10:37 PM (GMT-05:00)
To: SPAme...@googlegroups.com
Subject: Re: [SPA] Re: Suggestions for Dirty Birdy Engine

The 3 screw adapter will accept a stock 744 OS muffler and works fine !!  When you order a Jett muffler order the one that fits a OS SF and it will bolt right on !!  You can also order a CR 60 F  that has a standard ex port and any OS muffler will bolt right to the block with out any adapter !!

The pictures is a R60 F with the adapter that comes with the motor and the OS muffler bolted on !!  Works great !!!

 

Dave

<001 (2).JPG>

<002 (2).JPG>

  

[Tommy Scarmardo]

A little pricey but the Jett 60 is the perfect engine for the Dirty Birty. It is the same size and weight of an OS 46 so should solve the problem of having to add weight to the tail of the DB...also lots of power !!

[Ddphill9]

Hi Scott,  On the carb thing, I have used both and can't tell a lot of difference !  The 10mm seems to have just as much throttle response as the 9 mm .  I took the mixture control arm off of my 9 and us it just like a normal carb !!  That's it in the picture ..

 

Dave.

ddph...@aol.com

[Jimmy Russell]

Yeah I know they can be a "big deal".  Had the rear cage come apart on a 46 ax and ruined the cyl in the process.  I just mean not that big of deal to change them out from the onset.

[Ddphill9]

One this I said about any OS muffler will fit is not true ! What I meant to say is any Muffler that will fit a OS SF will fit on the Rossi adapter and the CR Block !!  Dub jet has only two mufflers for the side Ex 60 size engine ! One fits his Jett Engine and the other fits a OS SF !!  THe one that fits the OS will bolt right on the Rossi adapter or the Rossi CR 60 F 

 

Ddphill9
ddph...@aol.com

 

 

-----Original Message-----
From: 'Ddphill9' via The Senior Pattern Association <SPAme...@googlegroups.com>
To: SPAmembers <SPAme...@googlegroups.com>
Sent: Thu, Jun 16, 2016 9:37 pm
Subject: Re: [SPA] Re: Suggestions for Dirty Birdy Engine

The 3 screw adapter will accept a stock 744 OS muffler and works fine !!  When you order a Jett muffler order the one that fits a OS SF and it will bolt right on !!  You can also order a CR 60 F  that has a standard ex port and any OS muffler will bolt right to the block with out any adapter !!

The pictures is a R60 F with the adapter that comes with the motor and the OS muffler bolted on !!  Works great !!!

 

Dave

  

 

ddph...@aol.com

 

 

-----Original Message-----
From: chuenkan <chue...@comcast.net>
To: Discussion, SPA <SPAme...@googlegroups.com>
Sent: Thu, Jun 16, 2016 2:33 pm

Subject: Re: [SPA] Re: Suggestions for Dirty Birdy Engine

I don't know who the "they" is, but I needed the NR adapter for the Jett tuned muffler I am using.

Phil Spelt, KCRC Emeritus
AMA 1294, Scientific Leader Member
SPA L-18, Board Member
Oliver Springs, TN  (865) 435-1476v  (865) 604-0541c

---

Jimmy,

Look at the Jett muffler for the NR.. they claim the os muffler and Jett will attach without any off set adapter.

S.

Sent from my Verizon Wireless 4G LTE smartphone

-------- Original message --------
From: Jimmy Russell <jameslela...@gmail.com>
Date: 06/16/2016 1:18 PM (GMT-05:00)

[Ddphill9]

This is a picture of the Nova Rossi CR 60 F with its spec sheet !!  The engine is the same on bore and stroke as the R60 F but uses a standard Ex set up !  This engine will except the OS muffler or  the one Dub Jett makes for the OS !! Great engine but cost more than the R60F ..

 

[chue...@comcast.net]

I'll second Dave's comment about the Jett bolting right on to the adapter.  Mine did with no problems, and it is a fantastic power combination.