daven

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The news hit the streets today, but it looks like Henry and Dave have developed a new Q40 Nelson motor that will be debuting in Phoenix at the annual QM Classic they have there each year.

I have noticed a few used Nelson Q40's on the auction site, keep your eyes open, if the engines do well next weekend, you may see a few reasonable Nelsons put up for auction.

[email protected]

Does Nelson have a website?

Going faster is always fun.

Mike

daven

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www.pspec.com

These engines turn a 7.4" x 8 pitch prop at slightly over 23,000 rpm.

hold on!

daven

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News hits the streets quick, I see 3 q40 nelsons listed at the big Auction site, and 1 Q500 motor. I'm not aware of a new Q500 motor, hope this isn't a sign.

Rudeboy

Dave,

What exactly did they change on the engine? Nelson has had his "European" engines on the market for quite a while now, and they do run VERY well. Are there any restrictions on crank diameter in 422?

HighPlains

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9 mm venturi. Must be an all new design since none of the old parts fit.

daven

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I haven't seen one Rudeboy, but its a complete makeover. I'm not aware of any restrictions on crank diameter, but as Highplains mentions its a 9mm max venturi (in the states with 15% nitro).

proptop

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Anybody got a "previously owned" one that they might be willing to part with for a negotiable fee?

daven

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Check ebay, 3 were posted last week, and there are several more on there now. They are still going for around $200, so still not cheap, but 1/2 that of new.

f3d

The new Q 40 is a long stroke engine.

And to do this the cylinder have on the top a extension ring. Same design as the new FAI F3d 40 Nelson engine.

Give the cylinder a better heat transfer to the case over the big flace and more stiffness.

Sorry my camera is without power. I will make pictures.

Best regards Michael

[email protected]

Well, how did the New Nelsons perform in Phoenix ?

daven

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Well, a new National Record was set with the Nelson LS.

They did have some issues with props failing due to higher RPM, which limited which props were allowed. The higher pitched props worked on some of the motors, but not all. I don't see the new motor going away, Lots of the older style motors have sold already, and more are coming. I see Marcus has his Nats motor listed from last year. He was leading most of the way through until an unfortunate collision with the #1 pylon pole. When top guys are selling their best engines, it tells me this motor is here to stay, and will be an improvement.

bob27s

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Seems like Fred is hard at work redesigning props ..... hopefully that works out ok.

Also hope there is not a lot of over-reaction from the lawyer type folks --- we have seen what sorta chaos can ensue from that.

I feel good that I pretty much retired from QM40 --- its F-1 all over again, just less nitro, and with some FAI mixed in.

daven

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Bob,

the progression started with the BSE, and then the resulting combination of Cast Case and newer innards in the Jett.

If the Jett guys hadn't started to get so fast, I think Henry and Dave would have been content without any major redesign.

I don't think its anywhere near Formula 1 at this point. There hasn't been any major changes in Q40 for close to 10 years. People have been spoiled with ready to run Carbon Fiber Props available from Fred. Sounds like Fred will get the prop issue situated and we will be back on track soon. No need to get lawyers involved, we are only talking about a 3% speed increase.

bob27s

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When I started in QM40, I flew a Miss RJ , glass fuse, foam wings - tissue and dope covering over balsa skins, owered by a Q-500 engine up front. Flew that the first season.

Second season was the first with a dedicated QM40 powerplant. In 1996 I flew Jett, Nelson and Edmunds power... all with some success. I struggled to learn to carve props (as I did in F-1 too). I only won with the Jett and with the Edmunds And I came about 100 feet of setting a national record (hit pylon 3). Same engine that flew 1:12 earlier in the year before the Nats, now in a Rich Tocci Stilletto - and flying sub 1:10.

Each year after that it was more airframe development and composite structures/fun wings that made the biggest improvements. Engines improvements were more in materials, and with learning how to cut props that worked for the engine and the new quicker airframes. Small changes in the muffler kept up with these.

I have a big box of QM40 props too - hours of carving, some purchased - good 4-5 years ago, still work fine on the older airframes, but obsolete now. I have two SideWinders and a Napier in the basement - all good 1:07-1:10 aircraft - not quick enough anymore, no cowls, bigger cross section - just off the mark for competition, but fun to beat on.

In 10 years we have taken the mark of success from the 1:10 range to the 1:00 flat range. Perhaps this doesnt seem like a lot, but Im sure you will agree, getting that 1 second a lap is not easy at all....

Things have changed a lot. Don't kid yourself.

Actually, the BSE and cast case "innards" have always been exactly the same. I was one of the first to race the BSE at the 2001 nats ...... I litterally stripped my cast engine and put the stuff inside of the machined case right at the field on practice day. Engine ran exactly the same RPM it had previously. The Jett's have been fast for the past 7-8 years. Design has not really changed much - I think Dub changed the liner material three years ago, but thats about it. Just not a bunch of folks flying them - that is why they make more of a scene and surprise folks when they do win.

So the BSE really wasnt a big jump in performance. In 1999 Bruce Richmond flew cast case to 1:00 flat in Dayton. Helsel won the Nats with cast case and BSE. The big jump the past couple of years was with props and the super slick composite aircraft that allow us to run the engines a bit different, since they were actually capable of flying quicker - different rpm and prop requirements. That actually helped things in the Jett camp - the airframes came around to the performance the Jett really wanted to run at.

The Jett QM40 engine requires a very different prop and load compared to the Nelson, and they start up and needle very differently on the starting line. So that is the reason a lot of Nelson guys tried jetts, and didnt like them - they are different, so those resistant to re-learning fail. You see more jetts going fast now, because newer guys, without habits to break, are flying the engines - and the new APC carbon prop sized for the Jett took that variable out of the equation.

Most definately the APC props helped level things a bit, once a few different sizes were made available.

Im sure you have seen in the past, the AMA react weird to even more obscure (and disaccociated) issues that came darn near to shutting down racing entirely at one point. That is what I was refering to.

HighPlains

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I would agree with Bob. The times have been stagnate since about the last 6-7 years. If Fred had been flying Jetts, or Chip (the prop that Fred copied), the Nelson would have been hurting for a long time. The only real improvement to the airframes was the death rule given to Mustangs.

daven

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Thanks for the history Bob, I've only been involved in Q40 for that past 5 years. I started with composite airframes, and have primarily been flying Lyles Vendetta design that has been available all that time (and now the National Record). So I really haven't seen much change since I started doing this.

You are correct, Dubb, Mike, and Jerry have been going fast with Jetts for a long time. In the last two years we have seen others go fast, exceedingly fast, with Jetts. At the past two Champ races, the JETT was arguably the fastest motor at each race. In Houston in 2005 they had the radar out with the display, and the Jetts there were a good 5-10 mph faster on average than the Nelsons.

HighPlains

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Lyle makes a good airplane. His Mustang is what I flew last. Although I don't think they were the fastest, you could point and shoot with it better than most.

bob27s

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I agree on the mustangs. The Dago, Stilletto,Stregas were more like flying pattern ships. The Bob Wallace mustang I flew for a while was truely on rails - and pretty quick too. (I think the wallace mustang with a Pete Reed foam/glass composite wing was about $220 as a kit).

QM40 has been quite dynamic over the years.

Lots of Jett success had less to do with the engine, and more to do with the props and the airframe. The Sidewinder Jerry Small came up with was the first step - excellent corner speed. The Polecat took that one step further, and was quicker straight line too. The quicker airframe made the engine unload a ton out of the corners. It was just the right match as folks noticed.

I think folks noticed last year that the Vendetta was more capable than anyone gave it credit for. I think it was DaveN that actually gave folks a thrill at the Nats with it a couple of years ago - with a good blazing heat. Make folks take notice. It has always been a good planform, and Lyles latest version is just a real good plane. Caught the polecat crowed off guard to some extent. The Jett pilots found just a bit more corner speed - engine rpm stayed up on step.

Even when the original 7.4x8 apc was available, the Jett couldnt use it... most of those guys were flying carved wood in 2004-2005. Rich Beers and a couple of others had a good prop design worked out. I think that was the last time I raced QM40, and I abondoned the black prop and went back to the lumber. If were technically allowed to alter the black prop (as I did for practice props) there was a big difference.

I like racing, and often change is good. It was always a lot of fun. I just couldnt justify putting a $700 airframe at mortal risk every flight. I'm not sure just how that is different then risking a $250 airframe each flight - but somehow it just is [&:]

mmattockx

Bob,

Are any of the older designs still available as kits for sport use? The super fast pattern ship comparison makes one sound very good for when I go all out and order a Jett 50 or 60. And I really like the looks of the racing Mustangs.

It's easier to justify the $250 airframe because it's easier to be in $250 worth of trouble with the wife instead fo $700 worth of trouble...


Mark

js3

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Bob27s,

Perhaps this discussion belongs in the pylon forums but you contribute a lot more frequently to this forum so I'll ask my questions here. In any case, the extreme speed prop guys like hearing what you have to say about Jett's motors.

What do you think this evolution in technology means for the Jett camp? Dub told me that there is an optimum bore/stoke ratio for every target RPM. Could it be that the ST X40--which has the same bore/stroke as the old Nelson and Jett--didn't hit the target?

Will we be seeing a new line of Q40 motors from Dub?

What about 428 motors? Rumor has it that there is a new Nelson Q500 motor on the way. But if the bore/stroke ratio is already optimized for RPM seen in Q500, would a new motor with a longer stroke make any difference?

Again, I really appreciate your insight and helpfulness.

bob27s

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Yeah, this thread and my posts have gotten off target a bit, and there is a similar thread in the pylon forum. Im not sure if too many sport speed guys really want or need any form of QM40 engine, but at least its good to know they are hitting the market for a value price.

Idunno on any new engines coming from Jett quite yet. Takes lots of R&D, money. There is no money in the racing engine business .. Dub will be the first to tell you that. Any new developement or engine would be just for pride and competition.

We know the existing QM40 engine works well. Works even better with the new smaller APC props. Problem was, at Phx when the props issue happend, everyone had to stop using the new props and revert to the old APCs or wood. Plus Dub, Mike and others had various issues which kept them out of any form of contention.

I believe Dennis went 102. And we know that in the past the exiting engine can break 1:00. So at least there is history.

For Q-500 ..... I hear new Nelson LS Q-500 is in work. Time will tell how it works. Probably will run strong. Nothing Henry or Dave put out is ever garbage. If it does, I would imagine in time Dub will consider something to compete with it. In the end, its all for fun.

Its a tight knit group of folks, everyone trys for an edge.

I thought I'd toss this little bit of history in here, since you mentioned the X-40 heritage on all of these engines.... might be of interest to others ...


1987 world championship USA team - Shadel 1st, Brian Richmond 2nd, Jett 3rd. Dub set at world record. All of the X-40 engines used by the team were prepared by Dub. A few years later in 1991, it was Dub 1st, Bartel 2nd and Shadel 3rd... similar X-40 derived engines. Eventually there were a few folks building different flavors of X-40 type engines.

HighPlains

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The thing that strikes me about that photo is the short wingspans.[8D]

bob27s

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Used QM40 planes are rare. We usually fly them to death [:'(], or they sell quickly when placed on display for sale at a race But on occation you can find them. Email Dub, sometimes the 'plane of the month' game results in a surplus of last-months airframes.

Matney Models has a foam/glass Napier still, and the T-tail AJ-2 too. http://www.matneymodels.com/qm.html
Im not sure if Lyle Larson sells and of the older foam/glass planes or the Dago any more.

Don Stegall was at one time going to kit some of the "older" QM40 planes for Sport QM racing (TT40 power). Not sure how all of that evolved over time. I seem to recall that he had a Duane Gall/Ed Smith Stinger kit. Kit was not expensive. Ideal for what you are talking about here. http://www.pylonworld.com