Great use for older Nelsons
02-23-2005, 07:11 PM
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Great use for older Nelsons
Hi Guys,
WellI just found out a great use for some of the older Nelsons the pylon guys sell. Although they may not be competitive any more for racing, they make one heck of an engine for extreme speed planes. I just got a .375 bore carb from Perry for a Nelson 40 Q-500 engine I bought for $175. The carb was $45. Well the plane I had the Jett 50 went from doing 145 9-8 to 168 on a 8 x9 APC. It does not idle as good as the Jett, but it is lighter, doesn't vibrate quiet as much and most of all GOES FASTER!!!!!!! The plane i have it in is a Sig Kobra. That is the .25 King Kobra
Crashin Mike
WellI just found out a great use for some of the older Nelsons the pylon guys sell. Although they may not be competitive any more for racing, they make one heck of an engine for extreme speed planes. I just got a .375 bore carb from Perry for a Nelson 40 Q-500 engine I bought for $175. The carb was $45. Well the plane I had the Jett 50 went from doing 145 9-8 to 168 on a 8 x9 APC. It does not idle as good as the Jett, but it is lighter, doesn't vibrate quiet as much and most of all GOES FASTER!!!!!!! The plane i have it in is a Sig Kobra. That is the .25 King Kobra
Crashin Mike
02-23-2005, 08:01 PM
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RE: Great use for older Nelsons
Mike,
You are correct!! Most guys that sell off their used Nelsons do so because they are off about 300 rpm from a newer engine. I just sold one this week for $175, and will probably sell another this spring to finance a new one. These engines are still in great shape for the average sport flyer, but can't compete at the highest level. I've never put a perry carb on one, but the standard Q500 motor does have a barrel to shut off, although it probably won't idle all that great.
You are correct!! Most guys that sell off their used Nelsons do so because they are off about 300 rpm from a newer engine. I just sold one this week for $175, and will probably sell another this spring to finance a new one. These engines are still in great shape for the average sport flyer, but can't compete at the highest level. I've never put a perry carb on one, but the standard Q500 motor does have a barrel to shut off, although it probably won't idle all that great.
02-23-2005, 08:04 PM
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RE: Great use for older Nelsons
One thing to keep in mind, you will need to buy Nelson specific plugs (they are bigger than the standard plugs used in sport engines). They are only $3 each, and if needled properly, will last a while.
02-24-2005, 07:31 AM
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RE: Great use for older Nelsons
Hi Guys,
I have done this too with the Perry carb and it is great! You should see how well it even works on a QM40 engine. The Jett 50 is a good engine but really only pulls to about 18,000, but the Nelson Q-500 will pull good the 20,000 + and the QM40 to well over 25. You just have to find the right props.
Hey Mike, you should share the Perry part# with the rest of the guys if you still have it. I am building a new "OLD" Larson Shark for my next speed play plane. I am going to use a Nelson QM40 ABC engine that is from 1999 but is almost new. Picked it up on Ebay for $150. Put a Perry on it and it turns the APC LP07870C 7.8X7 Carbon Fiber prop at 22,000 so it should be a blast. By the way it will throttle back to about 7000 very reliably
I am going to put a post on the pylon section to let the guys know about the carb. It really makes the first flight on a new QM40 a lot safer with the carb and all you need is a new throttle pushrod for the test flight.
David
I have done this too with the Perry carb and it is great! You should see how well it even works on a QM40 engine. The Jett 50 is a good engine but really only pulls to about 18,000, but the Nelson Q-500 will pull good the 20,000 + and the QM40 to well over 25. You just have to find the right props.
Hey Mike, you should share the Perry part# with the rest of the guys if you still have it. I am building a new "OLD" Larson Shark for my next speed play plane. I am going to use a Nelson QM40 ABC engine that is from 1999 but is almost new. Picked it up on Ebay for $150. Put a Perry on it and it turns the APC LP07870C 7.8X7 Carbon Fiber prop at 22,000 so it should be a blast. By the way it will throttle back to about 7000 very reliably
I am going to put a post on the pylon section to let the guys know about the carb. It really makes the first flight on a new QM40 a lot safer with the carb and all you need is a new throttle pushrod for the test flight.
David
02-24-2005, 11:18 AM
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RE: Great use for older Nelsons
Sounds like you have a fun toy! 
Retired racing engines are always a good find. Dub has them on the Hangar Sale requently, and lots of folks are thrilled to get an engine like that (as Dave noted, it lost 300-500 rpm for racing, but it still screams compaired to most)
Of note....
The Jett SJ-50 is rpm limited by the stock jett-stream sport muffler (15,000 to 18,500 rpm range). This set up intended for sport props in the full blade 9x8, 9x9, 10x6 and 11x5 range. It will actually turn the same rpm as the Q-500 engine on the 8.75x9W prop, by using the Q-500 muffler (18,500 to 21,500 range). Dub sells SJ-50 engines configured that way for folks sport flying Q-500 birds quite often. The limitation is you now must use the q-500 props to keep the engine up in that rpm range. The advantage here is with the sport engine port timing, the engine still has a perfect midrange and idles great. And you can always swap back to the longer muffler and use it for sport flying.
Dub also offers the 428 Q-500 engine with the red carb installed as an option, which is about what you have there with the perry/Nelson comination. It only loses about 300-400 rpm off from the racing 'air valve' carb. And, it will idle and transition - just does not like to run in the midrange for a great deal of time, and you are restricted to the Q-500 type props to really allow it to run well (will not run worth a hoot with the longer muffler).
(edit - boy my spelling just great today........shhessh!)
Retired racing engines are always a good find. Dub has them on the Hangar Sale requently, and lots of folks are thrilled to get an engine like that (as Dave noted, it lost 300-500 rpm for racing, but it still screams compaired to most)
Of note....
The Jett SJ-50 is rpm limited by the stock jett-stream sport muffler (15,000 to 18,500 rpm range). This set up intended for sport props in the full blade 9x8, 9x9, 10x6 and 11x5 range. It will actually turn the same rpm as the Q-500 engine on the 8.75x9W prop, by using the Q-500 muffler (18,500 to 21,500 range). Dub sells SJ-50 engines configured that way for folks sport flying Q-500 birds quite often. The limitation is you now must use the q-500 props to keep the engine up in that rpm range. The advantage here is with the sport engine port timing, the engine still has a perfect midrange and idles great. And you can always swap back to the longer muffler and use it for sport flying.
Dub also offers the 428 Q-500 engine with the red carb installed as an option, which is about what you have there with the perry/Nelson comination. It only loses about 300-400 rpm off from the racing 'air valve' carb. And, it will idle and transition - just does not like to run in the midrange for a great deal of time, and you are restricted to the Q-500 type props to really allow it to run well (will not run worth a hoot with the longer muffler).
(edit - boy my spelling just great today........shhessh!)
02-28-2005, 10:02 AM
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RE: Great use for older Nelsons
Not sure if the Jett carb will fit a Nelson, but I believe you can get a carb from Dave Shadel at www.pspec.com that will fit the Nelson. I know he use to sell them.
