Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Best engine for a Patriot XL?

Reply

Old 09-03-2009, 12:30 PM
  #1  
Quikturn
Thread Starter
My Feedback: (12)
 
Quikturn's Avatar
 
Join Date: Jan 2008
Location: West Des Moines, IA
Posts: 837
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Best engine for a Patriot XL?

I just purchased a Great Planes Patriot XL from my local hobby shop as a future project. I'm conducting some engine research and would like some input/opinions as to what would a great choice.

As far as the build goes, I'd like to keep it light. But I plan on installing retractable landing gear and flaps (more for fun than function).

I have an OS 61 FX and OS 61 SF pumper available but these fall on the lower side of the suggested power range. Does anyone have experience with this airplane with a 60 size engine in it? I started another post on Rossi engines as an alternative.

If I opted for a 90 size engine my concern would be prop clearance, fuel consumption and weight.

Quikturn is offline  
Reply With Quote
Old 09-03-2009, 02:43 PM
  #2  
SpeedBoy
Senior Member
 
SpeedBoy's Avatar
 
Join Date: Nov 2007
Location: Monterrey, MEXICO
Posts: 461
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

Hi ,

I think a good option would be an OS 91 FX with jett muffler or tuned pipe it weights the same as the 61 FX and if Im not wrong just like 50 gr more than the OS 61 SF and you dont need to worry about prop clearance , 11" is enough to this aiframe I think , the rest of the power you can use it on pitch .[8D]

Theres a thread that freakingfast opened on tachometer readings with very useful info , many props tested thinking on speed including 11". Take a look there and get an idea what you can have with this engine , of course Rossi engines are always good options just more weigth.

Or if you are willing to spend on a jett engine a .90 would be good as well I think.
SpeedBoy is offline  
Reply With Quote
Old 09-03-2009, 04:20 PM
  #3  
porthole200
Member
 
Join Date: Sep 2007
Location: putnam, CT
Posts: 73
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

I am flying my Patriot XL using a Supertigre 90. It has a Jett muffler and spins a 13-6 or a 12-8 without any ground clearance problems. Weight is 8.5 pounds (no retracts) and it sure does move right along. It does slow down when using the flaps for landing.
Attached Thumbnails Click image for larger version

Name:	Nl29061.jpg
Views:	22
Size:	176.9 KB
ID:	1268109  
porthole200 is offline  
Reply With Quote
Old 09-03-2009, 06:27 PM
  #4  
smoknrv4
My Feedback: (11)
 
smoknrv4's Avatar
 
Join Date: Dec 2003
Location: RR#7 Aylmer, ON, CANADA
Posts: 1,285
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

I had a O.s. 91Fx in mine for a while, with a tuned pipe, but it was a dog compared to the JETT 90l I put in it.
smoknrv4 is offline  
Reply With Quote
Old 09-05-2009, 07:47 AM
  #5  
sarpet
Senior Member
 
Join Date: Feb 2007
Location: joutseno, FINLAND
Posts: 244
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

iuse webra .90P5 with webra pipe and 12x12 prop. but some high rpm rear exhaust engine would be better.
sarpet is offline  
Reply With Quote
Old 09-05-2009, 09:09 AM
  #6  
freakingfast
Senior Member
My Feedback: (3)
 
Join Date: Jan 2005
Location: Mather, CA
Posts: 2,222
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

The OS 91 FX on a Macs 11cc muffled marine pipe (#1369) will turn a APC 11X 12 at 12,750 and the 11X14 at 11,700 on 15% and a few hundred less rpm on FAI fuel. APC does not list the 11X14 anymore, but you may have to hunt around or call them. Their new website list is not as complete as before.

With the rpms listed above, here are the pitch speed and thrust numbers: 11X12 = 145mph & 11.27 lbs. 11X14 = 155mph & 10.48 lbs.

Just for giggles; OS 91 heli & tuned pipe 11X12 @ 15000 pitch speed 170mph & 15.6 lbs. You would need a huge fuel tank for that one..chuga-lug, chuga-lug!

Serpent's Webra .90P5 12X12 @ 11500 = pitch speed 131mph & 12.3lbs. This engine would be cool with a 11X14. Potentially, a stronger engine than the OS.
freakingfast is offline  
Reply With Quote
Old 09-05-2009, 06:24 PM
  #7  
Quikturn
Thread Starter
My Feedback: (12)
 
Quikturn's Avatar
 
Join Date: Jan 2008
Location: West Des Moines, IA
Posts: 837
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

Thanks for all the input guys. Sounds like the 91 FX will be the way to go without killing my wallet. Reviews for this engine seem positive overall.

Freakingfast, thanks for those performance numbers. Any thoughts on an OS 91 FSR other than being and older engine?
Quikturn is offline  
Reply With Quote
Old 09-05-2009, 07:39 PM
  #8  
freakingfast
Senior Member
My Feedback: (3)
 
Join Date: Jan 2005
Location: Mather, CA
Posts: 2,222
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

Picked up four 11 X 14 props (LP 11014). There were 7 more on the peg at RC country in Sacramento CA.
Don't know how this will work with the OS 91 FX & clean plane, could be too much prop, only one way to find out...for a future project.
freakingfast is offline  
Reply With Quote
Old 09-05-2009, 10:58 PM
  #9  
lfinney
Senior Member
My Feedback: (44)
 
Join Date: Feb 2008
Location: kuna, ID
Posts: 896
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

last thursday we went out to emmet for a float fly, one the guys there had the best "enforcer i have ever see, to myself it thought what a waste of wood and engine, but the builder fired it up, and i perked up, he said he ran 25 percent nitro in the motor, and it flat hauled, i am a skeptic, and had some questions for him, it was scratch built and his sixth or seventh one, so the thing that got my interest was his remark, that the engine really perked up with the nitro, which isnt always the case, so i went to read about the 91 os heli engines, and they are very interesting, huge carbs good rod and crank, etc, they could be the engine to try with the head trimmed down, the carbs have a ten MM bore in the non pumped version[:-], and a bit more exhaust timing too
lfinney is offline  
Reply With Quote
Old 09-06-2009, 03:33 AM
  #10  
freakingfast
Senior Member
My Feedback: (3)
 
Join Date: Jan 2005
Location: Mather, CA
Posts: 2,222
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

The OS 91 Heli engines and the OS 91 FX are so different that they may as well have been made buy two different companys. The only things they seem to have in common is displacement and they are both two strokes.

The FX is rated at 2.8 at 15000 rpm and I was never able to find worthwhile power at those higher rpms even with a tuned pipe, however it did achieve 2.4 hp around the 12500 range on the pipe.

The best I've seen others do with the heli engine is 3.6 hp @ 15000 on 30% with tuned pipe and the fuel consumption at full power is hideous. When used in a helicopter the fuel usage is not as bad because most of the flying is done at half throttle yet the punch is available for the moments it's needed.

Ifinney, I think you have a good idea with the notion of raising the compression on the heli engine, that would allow one to use low or no nitro fuel for a cost savings yet retain most of the original power. Low nitro fuel will need to be run at a leaner needle setting than before, again saving fuel costs as well as increasing flight time. You would have to raise the idle speed and the needle setting will get a bit more touchy.


Quickturn, I don't much about the OS 91 FSR other than it's a very strong engine, if you find one cheap and in good condition, go for it, but you wont find parts for it.

The OS 91 FX are popping up all over now that the 95AX is out, so there are deals out there.
freakingfast is offline  
Reply With Quote
Old 09-06-2009, 05:26 AM
  #11  
sarpet
Senior Member
 
Join Date: Feb 2007
Location: joutseno, FINLAND
Posts: 244
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

new os .95ax??
http://www.osengines.com/engines/osmg0580.html
sarpet is offline  
Reply With Quote
Old 09-06-2009, 09:12 PM
  #12  
EdwardB
Senior Member
My Feedback: (6)
 
EdwardB's Avatar
 
Join Date: Feb 2002
Location: Lake Orion, MI
Posts: 181
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

Went through this decision process a couple of years ago when I built my Patriot XL. The trick engine for this model is clearly the Jett .91. I've used Jett engines before and highly recommend them. Unfortunately, my current club field has a 94db noise restriction, and this took the Jett and most other piped engines out of the picture. I ended up with an O.S. 120AX. The case and weight are only slightly more than a .91, and it easily meets the noise restriction. I'm using a 14-12 prop. It won't win any all-out speed contests, but it's one of the fastest models at our field, and plenty fast for me. If I were building the model today, probably I would take a look at the new .95AX assuming it's quiet like the 120AX. But I'm very happy with mine the way it is.

A word about the prop clearance. With the retracts installed exactly per the plans, and with the recommended Robart gears, the stance is decidedly "nose down." A number of forum posts talked about it being hard to take off. No doubt. I put a spacer under the nose gear mount to get it as low as possible. Now the stance is right, the 14 inch prop works OK even on our grass field, and it takes off with just a little elevator back pressure. The trade-off is that the nose wheel doesn't completely retract into the fuse. Probably about 1/2 to 3/4 inch of the tire shows. But, not a big deal. Works for me.

Here's a picture of my Patriot XL. Flew it just this week. Love the high speed low passes.

Attached Thumbnails Click image for larger version

Name:	Xv63890.jpg
Views:	24
Size:	152.8 KB
ID:	1270120  
EdwardB is offline  
Reply With Quote
Old 09-07-2009, 01:34 PM
  #13  
jeffk464
Senior Member
 
Join Date: Oct 2004
Location: Lehi, UT
Posts: 1,692
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

AX engines are fantastic, they are built for reliability, easy tuning, low noise, and torque like a 4 stroke. Bad side is stock they really aren't built for high speed high rpm. I think I have read threads where people put a aftermarket exhaust and turn them into speed engines, but not stock.

P.S. whenever I fly my 55ax and someone else goes up I can no longer hear my engine.
jeffk464 is offline  
Reply With Quote
Old 09-08-2009, 06:40 PM
  #14  
Quikturn
Thread Starter
My Feedback: (12)
 
Quikturn's Avatar
 
Join Date: Jan 2008
Location: West Des Moines, IA
Posts: 837
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

Seems to me there's not much advantage of the 95AX over the 91FX. $40 more (retail) for .1hp more and maybe the ability to swing a bigger prop. For the money, I'm still leaning towards an FX 91 especially now that you can pick them up for less than $200 new.

Freakingfast, the heli version of the 91FX sounds hot but fuel consumption kind of defeats the purpose. Don't the heli versions have a shorter crankshaft and a long carb arm too?

I think the evolution of OS has been to make quieter engines. FSR's were loud, then SF's came along as a long strokes to make them quieter. Not sure what advantage the FX series had and now the AX series are reportedly quieter due to the new power box muffler.
Quikturn is offline  
Reply With Quote
Old 09-08-2009, 08:43 PM
  #15  
freakingfast
Senior Member
My Feedback: (3)
 
Join Date: Jan 2005
Location: Mather, CA
Posts: 2,222
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?


ORIGINAL: Quikturn



Freakingfast, the heli version of the 91FX sounds hot but fuel consumption kind of defeats the purpose. Don't the heli versions have a shorter crankshaft and a long carb arm too?

You just need the prop drive hub that the 60 or 91FX uses and the shaft length is fine. I shortened the throttle shaft myself.

I think you are on the right track with the 91 FX.
freakingfast is offline  
Reply With Quote
Old 09-08-2009, 09:54 PM
  #16  
Quikturn
Thread Starter
My Feedback: (12)
 
Quikturn's Avatar
 
Join Date: Jan 2008
Location: West Des Moines, IA
Posts: 837
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

EdwardB Nice job on your Patriot! I see you left out those plastic inlets too.

The 120AX is a lower rpm engine developing peak power at 9k rpm. That explains why it's quiet and not super fast. Like you, I'm not looking for the fastest airplane but a fun one.
Quikturn is offline  
Reply With Quote
Old 09-11-2009, 02:43 AM
  #17  
kmtranmd
My Feedback: (71)
 
Join Date: Sep 2004
Location: Irvine CA
Posts: 884
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

Don't need to reinvent the wheel with this airframe. Proven combo without breaking your wallet is: OS 91FX, Jettstream tuned muffler, APC 11x9. Tune engine to about 12K on the ground, or about 500 off peak to let it unload in the air with the Jettstream. Expect to hit speed in the 120-130mph range. If willing to spend another $150, then go for the Jett 90 motor to pick a little more speed, may be 5mph more but sacrifice with more noise problem. Heli engine is interesting but that motor is spendy unless you already have it. I don't see the point of spending the money for the heli engine and make it work when you can just go out and get the Jett 90. Be careful with weight issue if considering 120 size motors. I already had to put a bit of tail weight to balance with the OS 91 motor. I've never tried the OS 120 motor but understand it's a torque engine, not meant for speed set up. When you get tired of flying the Patriot, another airframe that can use this power set up and better looking is the Cermark F16 propjet.
kmtranmd is offline  
Reply With Quote
Old 09-11-2009, 05:46 AM
  #18  
dhal22
 
Join Date: Aug 2006
Location: Roswell, GA
Posts: 5,619
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

kmtranmd, well said.
dhal22 is offline  
Reply With Quote
Old 09-12-2009, 11:02 PM
  #19  
Quikturn
Thread Starter
My Feedback: (12)
 
Quikturn's Avatar
 
Join Date: Jan 2008
Location: West Des Moines, IA
Posts: 837
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Best engine for a Patriot XL?

If anyone is interested, there is a Patriot XL listed on ebay. Unassembled kit.
Quikturn is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service