bob27s
Posts: 4637
Joined: 4/9/2002
From: Cleveland,
OH, USA
Status: offline
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Hi Azuz,
First...yes, those are 40 size Lanier Shrikes 
Just for info..your first post asked about ABC/AAC. The Sport Jett engnies (cast case) are now only available as ABC engines. The new BSE machined engines are available ABC or AAC. Both run basically the same, the AAC just weighs less, and cost a bit more.
The QJ-40 engine itself will run with a 10x6 prop, but it requires the SJ-40 muffler to do it.
Basically, the SJ-40 is the same engine as the quickie engine. It just comes with the longer, sport RPM muffler and a fully funtioning two needle red-jett carburator.
The Q-500 engine with the "air valve" carb is not intended to idle or midrange.
If you want the power, idle and reliability of the SJ-40 or SJ-50 along with the higher RPM of the Q-500 engine, you can order the sport engine with the SS-40 muffler (about 500 rpm higher) or the q-500 racing muffler, such as shown here
http://www.jettengineering.com/hall/index.html scroll down to Andrew Steadman's Predator.
As far as props go, you can pretty much use a variety of props. High quality reinforced props (APC, Bolly, etc) or good quality wood props are essential. You must make your selection so that the engine runs at or above the target RPM specified for the engine. Each engine/airplane combination will work best with a different prop.
Jett does not have a prop/rpm list. But we do have significant experience and feedback (such as on the HOF page) with differnent airplane/engine combinations.... so we can usually make recommendations based on that.
We fly the QJ-40 and BSE-Q40 engines for racing with the APC 8.75x9W, 8.8x8.5 or 8.8x8.9 props. All of these will turn over 19K on the ground, and well over 20K rpm in the air.
For the SJ-50 with its standard muffler, anything from a standard 9-7 APC, 9x8, 9x9, 10x6, 10.5x5, 11x5 (a bit tricky to set the needle, but it works). The APC q-500 series all work well, up to the 8.8x9. I have even run a 12x4 on my SJ-46.
A lot depends on how fast the airplane is capable of flying. For a Q-500,Diamond Dust, Whiplash, and even the Shrike, a smaller 9" or 8.75" prop turning higher RPMs will work well on the SJ-46 or SJ-50, because the engine will be able to unload in the air as the plane accelerates. A SJ-50 will turn a 9x8 APC at around 18K rpm. It will also turn a 9x9 at about 16,500 on the ground...and if you are careful and set the needle right... it will unload and go like heck in the air.
On something like my P-51 mustang (more of a sport plane), the airframe and thicker wing simply is not going to permit the plane fly quite as fast as a Q-500, so running the 10x6 or 10.5x5 prop at a bit lower RPM works best for me there. The plane is still pretty quick, and the SJ-46 easily turns an APC 10x6 at 16,300 while still rich. I have flown the plan with a 9x7, and yes, the engine screams, but the result is a longer take-off roll, and pretty much the same in-flights speed.
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Engine Manufacturers Direct Support Forum >> Jett Engineering Support >> Super Jett .50 or Quikee Jett 40 
Super Jett .50 or Quikee Jett 40 - 
BTW doesnt the Q J 40 come with a carb ?? is that a different one