jprge C.

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Hello,
I have a question, how do AMA 422 planes (Quarter 40) fly with Jett 50 engines? Reason I ask is someone I have bought a bunch of stuff from over the years has a few 422 planes he is selling and I am thinking about putting my Jett 50 in it. It originally had a Nelson short stroke. I could put an airvalve on it, but I love the way the Jett's run.

Jorge

daven

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Jorge,

It would fly just fine on the sport Jett 50. When we first start racing Q40's up here in Minnesota we used the Q500 motors and they worked great. You may find that it is easier to land dead stick, they really take a while to slow down on landing.

bob27s

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Its been done many times, and results in a great flying plane.

Quite a few folks have set up the QM40 planes with sport jett engines. A few others have used retired 428 Q-500 engines, sometimes adding a throttle carb to give throttle control.

Usually the trick is finding a retired QM40 to put it in ! If you build from scratch, then not a problem.

The engine mounts for the QM40 engines have a different mounting bolt pattern than the Sport Jett engines so that is one thing to keep an eye on. Not a problem really, but may require some thought on the installation, or replacing the mount.

For a prop, go with a 8.8x8.5 q-500 prop, or what ever you have in the size range. Most qm40 planes actually have ground clearance to deal with up to a 9" diameter blade.


In fact ... the QM40 planes fly just fine with a TT40pro and a 9x6 prop up front too!

Ed Sabini

Hi Bob,
I have read many of your posts and i see here you are doing just what I posted a question about. I found a real nice pylon racer online for sale, and was thinking about trying to snipe it and put my 46 Jett in it. This is the plane, are you familiar with it? It is also a qm40 plane like yours. Do I need more than my 46?

Thanks
Ed

diggs_74

The .46 Jett would be perfect.. I haven't flown a that specific plane but really most of the Q40's fly quite well so I wouldn't hesitate to give it a try.. I've got an old Dago that I busted up during a midair on takeoff and I've been thinking about "sporting" it.. Hmmm, might be a good project for this winter..

bob27s

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I am indeed familar with that plane. My friend has it for sale. It is a Rich Tocci Stelleto I raced one just like it very successfully for a number of years.

Keep a sharp eye on it.... its probably not going to go cheap.

Would be perfect for the Jett 46.

ChrisAttebery

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I bought a Q40 plane this year RTF with a Nelson SS. I added an OS heli carb to the motor and it works fairly well. One warning is that these planes take a long time to slow down and they will tipstall if you get them too slow. I've already had two crashes from coming in too hot, and then either trying to turn or feeding in too much elevator and stalling the wing. Luckily both were at 20' or less and into tall grass. The plane is a little worse for wear, but it's still flyable. I'd recommend a Q500 first if you haven't flown a racer before.

bob27s

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On final decent, landing setup and the turn to landing approach..... use have to use the rudder to keep the nose down in the turns.

The planes will slow down fairly well, but you have to be in level flight .... and expect that the ailerons will get very soft. Keep the nose down just slightly until you are level and on final. Once the nose comes up they will slow down fairly rapidly. Its a feel thing... if it gets mushy, push the nose down a bit right away or it will just stop flying.

Once on the ground be sure to release any up elevator you are holding.

Takes a little practice. But you can put it right on the mark every time.
http://www.lcrc.org/Tony/Videos/2006...ng%20plane.wmv

The Stilleto was one of the best QM40 planes I ever flew. No bad habits at all.

Ed Sabini

Hi Bob,
GREAT video, that is exactly what I want to do. He told me if I wanted he would put an airvalve on a Nelson he has for it and it would at least come down to half power if I went that way. What Jett was in your plane in the video, that thing really booked!!!

As far as hard to fly, my practice planes have been a SIG Kobra with a Jett46 and the K&B FIRE. The same guy that has the Stiletto for sale sold me a plane called a Pacemaker 500 ready to cover for $130. I just finished it and will test fly it Friday AM. I have my os 46 SF ABC with a Nelson muffler in it. He told me to run APC 8.8 x 8.5 , he gave me a few. and said the plane should be in the 150 range. I can't wait!!! The engine turns 17.500 at it is still rich. If I turn it in it peaks to 18,100.


Ed

bob27s

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You are dealing with the right person... trust me on that

Does sound like you are pretty good to go ! You will enjoy the PaceMaker.

The engine in my old SideWinder is a Jett QM40 engine. As flown there was using a wood (carved) 7.25x7.5 prop. Just a good running setup, and in 2001, 2002 it was a competitive aircraft. It is retired from racing, and I use it for demos and shows like that. The current QM40 aircraft, APC carbon prop, and Jett Q40-2 engine runs about 10-12 mph quicker.

russm

nice video bob. how many times have you hit the flagpole? good imfo in this thread. where are these planes available.

bob27s

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the flag pole? at the field there? Its actually back behind the flight line a little. But I have in the past gotten "blinded" by the flag on final approach

russm

off the subject, dissapointed the stock gp viper engine mount did not fit my 60lx. no problem with my rossi 40. what gives ?

bob27s

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Idunno.... let me check.

Ive never tried one myself to be honest... usually use the integral backplate...

I have the Predator mount on my SJ46 .. that fit ok. From what I recall the Viper mount was pretty much identical.

I do know the jett backplate is about the same size as a TT40 backplate (bolt array).

The only thing you should need for it to fit is some longer 5-40 screws.

Bob

edit....

In what way does it not fit ? The slotted bolt pattern should fit everything from an OS32 through upwards of an OS55 or Rossi 53

YUKONFLYR

Bob - Would you happen to know the CG and throws for the Rich Tocci Stiletto??
If so it would appreciated

Duane-RCU

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WOW! Thanks for the video Bob! Those videos and NHRA Pro Stock sounds seem to be able to make me quit breathing. I also came up with an old plane (what is it, Dago Red?) What is the bolt pattern on the 422 engines? The mount is glassed at the front, so it's not easily changed. Maybe my Webra .40 will fit? I think that's what I'll use, or my old 6 head bolt ST .45, I know the ST will need new holes drilled for the front of the mount, Webra is on a plane right now so I can't get a measurement.

bob27s

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Not sure... but it is easy to figure out.

Measure the wing Chord at the fuselage. It should be appx 9"

If so, balance it 2.25" aft of the LE.

Otherwise... just shoot for 25% of what you measure. If you measure 250mm, set the CG at 62.5mm.

It will be slightly nose heavy there. Adjust back as you get more comfortable flying it.

Bob

bob27s

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Nice Dago apparently it had a Jett BSE 40 in it at one time ..... jsut a guess.


Engine bolts the racing engines use the old ST X-40 mounting pattern. Its a bit smaller than the more common OS46FX standard that has sorta come about over the years.

Check the Webra .40 first. The older ones shared mounting patterns with plder ST engines. Ya might get luck there.

Option for mounting.... if you are not worried too much about it, slot/enlarge either the forward or aft holes on the crankcase lugs. Mount the engine first so you can see which set matches up to the spinner position properly.

Either engine you have will fly the plane just fine. Put a 9x6 prop on the front and fly it. The Dago should have enough ground clearance. If not, find one of the APC 8.8x8.5 props (or similar) and clip it down to 8" diameter. (the cut bigger props will work better than using a stock APC or wood 8x8)