petec

My Feedback: (58)

I was at Henry Nelson's before he sent the whole works South, it was nice to see that the engines were going to continue in production. I sold my SS and never should have but one of these days a LS will happen for me again.

combatpigg

My Feedback: (3)

I think it'll either take $100 worth of custom props to find out or else pose the question in the pylon forum as to feasibility .
I think the NPRA is the national org and they might have a forum too.
The AMA magazine's columnists are also very approachable.
I think a trained "engine dynamicist" could take the fuel demand of a few different proven 200 mph .40 engines and backwards engineer what it takes in breathing ability to "do the number".
As for running your engine, I'd start out with 15%, look at the plug often and look at the head after a few runs. The head space above the piston should develope an amber varnish with no signs of "sandblasting" going on.
Gradually juggle load, compression and nitro content just like you would if you were playing with an expensive model diesel engine. It's a balancing act.There is never any hurry to get too aggressive, because at this level of power bad things can happen faster than you can close the throttle. It's possible to have a "smokin' run" without actually landing with an over heated engine if you pay attention to L,C & N%. If you do, then it makes controlling the mixture that much easier because you are exercising some amount of temperature control.

MJD

My Feedback: (1)

For sure I'll need to be a bit more serious about paying attention to details than I have become accustomed to. The approach I want to take is the same as for example the DF .65's - run them happy but not too hard and keep the mixture under control or so I hope, in the air with the IMC.

I am SO buying a transmitter tray this winter - I like the model Esprit has. And the transmitter tray too..

GREG DOE

C-pig The NMPRA web site is nmpra.org To clear things up a little, Michael Langlois is only making the Nelson Q-40 front intake, side exhaust, long stroke engine, and his web site is; http://aeroracingengines.com/ Henry Nelson wanted to slow down a little, so he turned the Q-40 engine over to Michael, but the last I heard Henry still supplied a few parts, and Henry Nelson still makes several other engines.
You have correctly pointed out that there are several different short stroke Nelson .40's out there. They are amazing engines, and I think any of them have the potential of 200 mph on the right air-frame. Today's Q-40's are pushing 200 mph. Parts may be a little harder to find for the short stroke's, but there were Q-40, and 428 Quickie fliers who were caught with service parts, when the long stroke hit the scene, and some parts, like bearings didn't change. Like a lot of subjects, there is much more to the Nelson engine story.

combatpigg

My Feedback: (3)

Greg, how fast was the FIRE Nelson with open header back in the Formula One days...?

GREG DOE

C-pig I'm going to have to guess on your question, because I was still running X-40's when I got out of F-1. I would say the fastest ones were in the mid 190's. I think either Chip Hyde, or Richard Varino had the last F-1 record at around 1 minute flat, but that was an exceptional time for those days. Today one minute times in Q-40 are more common. Greg

smoknrv4

My Feedback: (11)

Was the F1 nelson a RIRE engine?
This is the one I have.

GREG DOE

Smokn, Yes that looks like what you have. Probably an old F-1 engine, but it could also be an early FAI engine. Since I never owned any of them, this is just my best educated guess. If anyone knows anything different, please chime in? At the time Formula 1 allowed rear exhaust engines, and the common wisdom then, was that rear intakes were more efficient. This was the arrangement of the K&B's and the Super Tigre's of the same era. A quick look at the exhaust port should reveal if it was cut for the mini pipe, or a tuned pipe. That would tell you if it was built for FAI or F-1. Keep in mind that while a few Canadian's flew F-1, more of them were interested in FAI. so if your engine came from someone in Canada, there is a significant chance it has a pipe timed liner, and set up for alcohol?
Greg

smoknrv4

My Feedback: (11)

What am I looking for in the exhaust port to tell me wether it was meant for the mini pipe or a tuned pipe? Also I bought mine from USA. I sent it in to Dave Shadel for new liner and piston too, Dave was very helpful.
Thanks for the info Greg.

combatpigg

My Feedback: (3)

Smokinrv.....you can do a quick timing check of the exhaust without any tools.

It might help to shine a LED spot light into the top of the cylinder to tell precisely when the exhaust port is about to open. At this point, place a mark on the spinner directly opposite a reference mark on the case [like a casting line or a webbing].
Rotate the engine so that the exhaust opens and then comes to the exact point where it closes again. If the mark you placed on the spinner is exactly opposite the original spot that you marked earlier, your engine has 180 degrees of exhaust. This is considered the base line of "pipe timing", though some engines I've heard of go to 190 degrees.
If your exhaust opens and then closes at somewhere in the 150 to 170 degree range, then the engine spends a little bit more time every stroke to build compression at lower rpm for handling a bigger prop. These engines can run pretty strong with just a short length of straight exhaust tubing or just wide open with no tubing.
Compared to listening to the musical pipe, the open header sounds pretty raspy.

GREG DOE

Smokn, C-pig got back to you before I could. Tuesday nights we fly indoor here in Smyrna. So that's why he beat me to the punch. His answer is about as clear as it can get. But the key to your question is that you sent it to Dave Shadel for a new piston and liner. He would not have installed a pipe timed liner unless you asked for it. That doesn't mean you can't use a tuned pipe, just don't expect a big boost from it. The FAI version of that engine will literally jump on the pipe when it hits the right rpm. I am curious about one thing though, is your engine equipped with a brass or an aluminum liner? Just about all the pylon engines built today have aluminum liners. Greg

MJD

My Feedback: (1)

I'd sure like to find some literature or anything on the tuned-exhaust version with carb I have coming. Can't find much on the 'net so far. Who would be the resident expert on that one?

combatpigg

My Feedback: (3)

Dave Shadel at Performance Specialties. He knows what the load bearing maximums and ball park clearances and fuels are.
All the advice I've ever rendered at this forum is just parroting the advice he has given me.
He doesn't just sit waiting at the phone all day hoping that people will call looking for free advice, so I've always mixed a certain amount of business with pleasure to make a few minutes of advice worth his time.
I've got one of the nitro burning FIREs and it isn't quite as powerful as it's FAI cousin is. I haven't spent any real time trying to optimize it though.
I don't care how much advice you get from a "Pylon Guy", unless you can talk to a RC Speed flyer you are pretty much on your own to find that perfect prop to marry the engine with your air frame.
Even the C/L Speed guys at Delphi Forums can only offer educated guesses.
If you recall the 200 Demon Project, I started with 2 fists full of different props and the first attempts were in the mid to high 180s [IIRC}. Even the "winning" prop needed some blade work to get over the top from being stuck at 198 - 199 for awhile. If it wasn't so expensive to play that game I'd do it more often, but between plugs and props and fuel it's pretty easy to blow $100 in just a couple hours.

MJD

My Feedback: (1)

Oh yeah, I got a good taste of that already. $16 "snaps" on landing, plugs, agggh.

If I can get a starting point on prop load and a few pointes I can go from there I think. Regards the FAI engines, I imagine they are running a lot more rpm than Form 1 - takes a bunch of chemical boost to make up for the increased fuel flow at higher rpm. I thought the Form 1 engines run in the 22-25k range and humped out a lot more torque due to nitro content. Or was that all 43 years ago and I'm out to lunch..?

combatpigg

My Feedback: (3)

That's the general idea, the nitro is liquid torque. It surrounds the fuel molecules better than oxygen alone and it also has some BTUs.
The higher nitro Nelson should have a generous sized "Double Bubble" shaped combustion chamber and possibly a collection of head and liner shims that came with it.
Dave's advise for bench running is just like with an unknown, brand new diesel. The difference is, you don't have a handy compression screw to play with, with a glow engine. An experienced diesel user knows the basic principle that if he is using a hotter diesel mix, he has to back off on compression screw or else go to a lower load, or else do both. The experienced diesel engine user knows that if he wants to try more prop, then the compression screw needs to be backed off. The diesel engine user does these things almost without thinking because the engine really "barks" at him when something is wrong.
With a piped racing engine on glow fuel, the warnings are more subtle and unless you make a point of gradually sneaking up on the most aggressive settings, it's easy to fry an engine.
Some people will blame a lot of this on incorrect needle settings and fuel foaming, but you've got those issues under control with the bubbleless tanks and on board mixture control.
I used to run a lot of 40% in 1/2 A and .36 sized combat and also used to burn up a lot of equipment, too. It wasn't until I was shown how to sneak up on the optimum compression and make sure to toss in 4 ounces of castor to every fresh jug of Power Master fuel that my engines held up as well as everyone else's.

rcguy59

My Feedback: (8)

I fly with a couple of fellow turbine guys who started with IC ducted fans back in the eighties. They learned after blowing up way too many $300-$500 big-block fan engines that adding 6 OZ. of castor to a gallon of 10% fuel made a world of difference in engine life. The Rolls Royce of those engines was the BVM. Buckets of power, huge RPM and idled like an OS .46. It should come as no surprise that the BVM engine was produced by Henry Nelson.

MJD

My Feedback: (1)

I tend to run ~23% oil in my piped engines, typically Omega 15% - containing 17% 70-30 syn/cas - plus 3/4 cup castor per gallon. They seem to like it.

combatpigg

My Feedback: (3)

I never knew Nelson had his hand in so many different engine classes until I started watching ebay.
I've always wanted to time it right and score a .36 Combat Special that some old timer never ran. They will bolt in place of any .32 and don't need a tuned pipe to be pretty awesome.

MJD

My Feedback: (1)

Looks like they may be available new? (For new price of course..): http://www.coxengineforum.com/t6464-...vailable-again

https://groups.yahoo.com/neo/groups/...messages/21997

MJD

My Feedback: (1)

WHEEE! https://www.youtube.com/watch?v=hy_cTTfJgp8

On a totally unrelated subject this popped up next to the above - too cool. https://www.youtube.com/watch?v=MKkCAaHBg0Q

smoknrv4

My Feedback: (11)

Hey cool vid! That's crazy good u control flyin!

heres a pic of my small Nelson collection.

combatpigg

My Feedback: (3)

Man..! You're set for life..!
You absolutely could spend a life time exploring all the possibilities with that herd of engines.

combatpigg

My Feedback: (3)

MJD..I never get tired of watching Fast Combat..! My Foxes are about 90 - 95% of that, but the extra 5% is really obvious in a match.
Thankfully, combat has a high luck factor.

smoknrv4

My Feedback: (11)

Did a quick check on the timing on the F1 engine(2nd from the top) and it looks like about 170* or so.

combatpigg

My Feedback: (3)

That [170*] makes the engine more versatile and easier to run. It'll put a smile on your face to see it come roaring out of the clouds.