LGM Graphix

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Ok, having an arguement with a couple of jet buddies who just bought old F1 planes, they're going to run Nelson F1 engines, and they claim they're breaking 200mph without issue, I call bulls***, none of the F1 planes I ever ran could hit 200 +. Anyone here with some REAL racing experience think they'll break 200 in straight and level flight? This is their claim, I'm to busy laughing to argue it :P

HighPlains

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Not even close to 200. A very good one could do about 175, but there were not too many above mid 160's. In a dive however, you could pick up a bunch of speed.

LGM Graphix

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Thanks high plains, that's been my experience as well, 200 MAYBE out of a huge dive, but I don't think I've ever had one of my F1 planes hit 200 and I've done some huge dives :P

sandslx

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I Look forward to seeing you eat a piece of Humble pie....I'll supply the coffee.

Justin

Rebellion

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I see this bench racing session has spread over here.

For those of you who might be interested I'll try to fill you in a bit. The whole thing started over a video of a Weston UK Magnum posted by Dave Shulman over at [link=http://www.kc-10.net/rcj/]RC Jet .net[/link]. You can find the thread [link=http://www.kc-10.net/forum/showthread.php?t=820]HERE[/link] if anyone is interested. The discussion got quite lively in the chat room last night with Jeremy being outnumbered two to one by Justin Sands and John VH. The final showdown should be quite interesting.

Bets anyone ?


Dave

JohnVH

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hey squealer, haha

this is going to be interesting...[>:]

AlW

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Hi All,
As someone who competed in Formula 1 for 20+ years a few comments are in order. First there is a major difference between on cource speed and long diving or level runs. The course was only 608 ft long so there was NO chance to get up to terminal velocity. In order to be competive in Formula 1 you needed to understand how to set up the motor for the particular climatic conditions, select the correct nitro content and most important select a prop which will make the motor run towards the top end of the power band and not ever allow it to get on the back side of the curve. A good combination will be around 170-175 on course. Now lets forget on course stuff and prop the airplane for long speed runs - prop will be higher pitched to stay on the power band , the motor will not be lugged down in tight pylon turns -200mph will not be out of the question.
Al Watson
NMPRA 15e

Ed Smith

Well maybe, but that is not quite the same thing is it?. My interpretation of an F1 airplane would be one that is set up for F1 racing. Can we get the airframe to go 200 mph? Probably. Certainly not with a high pitch prop. A high pitch prop would lug a racing motor down at the very beginning. The motor would be cooked in very short order.

Back at the beginning of this year on the extreme speed (read dreams) thread we were promised a twin, piped Jett delta that would go 200 mph straight up. I bet a case of real Canadian beer to a bottle of rum that one of my AMA 428 racers would beat it. Do a search on "Boogie Boards" and read the results of that. Whenever speed dreamers dream of speed the magic 200 mph floats by on a cloud.

Ed S

Ed S

daven

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Ed,

Your always good entertainment.

Per_N

I'm not sure what you mean with formula 1, but the F3d planes surely beats the 200 miles limit easy.

daven

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Different Animal Per

Ed Smith

Well not easily. 200 mph is approximately 320 KPH. Chris Callows fastest time in France was 56.98. This is truly a healthy time but it is only a couple of seconds faster than the US Q40 record flying basically the same size course. The Q40 racers are not close to 200mph.

Ed S

HighPlains

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The FAI have two big advantages over the American Q40. The course is wider at 2-3 for lower g loading, and the wingspan has no limit which cuts drag in the turns.

Terryoc

The course being wider at 2-3 is no advantage this makes the straight shorter so less time to build speed and a bigger turning circle is drag for longer or as Chris Callow flys a turn at 2 and a turn at 3 so an extra turn .
What would be interesting would be a good F3D on the Q40 course , anyone for 53's
Terry

JohnVH

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OK guys, we did an offical run today, with a used nelson motor, and and old prop, used plug.. etc... flat and level on 30% fuel and richened up to 21K on the ground it went through the traps at 207.4MPH This was with NO DIVE... it easily broke 200MPH, we will be doing more runs tomorrow.

Doug Cronkhite

My Feedback: (34)

175mph average on the course would suggest over 200mph straight line speeds. Turns scrub quite a bit of speed off I'd think. At least turn 1 does, and 2 - 3 not so much.

daven

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Sounds a bit faster than I would expect, looking forward to future tests.

Ed Smith

Simple arithmetic tells me that to achieve that speed at that rpm requires at least a 10.5" pitch prop. That is ignoring all of the inefficiencies associated with whirling propellers and the drag of the airframe. If those factors were added in at the generally accepted (Not totally accurate though) figure, the required prop pitch would be somewhere close to 12". Something does not add up here.

It is not that I am from Missouri or anything but.....................

Ed S

daven

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John,

the only reason Ed and I are skeptical, is that we currently run Nelsons on smaller, cleaner, and lighter q40 airframes with a nelson turning closer to 24,000 rpm and see straight line speeds around 185 mph.

HighPlains

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Ed, I guess I am going to move one state to the right also. These engines without a tuned pipe unload much more than people realize. Typical unload was in the range of 5K, determined by an audio tach and the effects of Doppler shift when the airplane is receding at 175. The amount of unload is limited by the airframe drag.

Back in the day, radar testing on my Stingers showed 175 as the peak speed on a course. Radar testing also showed that flying in knife edge was about 5 mph slower than rolling back to about 45 degrees while on the course. The average speed for the fastest times recorded was in the mid 150's.

"traps" suggest parallax error, and thumb on the stopwatch error (x2)

Ed Smith

Dave,

You have that right. look at the amount of work we have to do to get those speeds. If 200 mph was that easy we would be carving wood props and doing it! 30% fuel does not make a huge difference over 15% fuel as evidenced by only 21k. 200mph at 21k using an old stock racing .40 in a 5 pound airframe? It just ain't so.


Ed S

JohnVH

My Feedback: (38)

Sorry, your wrong, it clearly is so. Just because you dont think it can be done, doesnt mean it cant. Eitherway, a speed trap system told us what we did. We are happy, besides that, this is a toy, we are flying this for FUN.. isnt that the point?

Ed Smith

John,

Actually no! Anything flying at that speed is no longer a toy.

My reason for disputing your claim goes far deeper than just deriding somebodies efforts to go fast. There is much more at stake here than that. Several years ago the current crop of Pylon Racers were always bragging about high speeds they were flying at. The AMA got to hear them and had a fit. The AMA insisted that unless a certain type of protective cage was constructed for the on course workers it would ban Pylon Racing. The racing fraternity had no choice but to agree. The AMA to its credit and its expense contracted an engineering company to design and build cages that would withstand aircraft impact at the claimed speeds. The AMA had ten sets of cages built at a cost of app. $5,000.00 each. the cages were dotted around the country for clubs to use. Then at a contest in Texas a Q40 went through a cage. Fortunately no one was hurt. At that point the AMA banned pylon racing. A compromise was quickly worked out whereby racing could continue provided that the cousre workers were placed off the course 450' back from the flightline. This layout uses up a lot of space. Many clubs did not have room to fit this layout on their fields. We lost a lot of racing clubs because of this. The AMA was still not completely happy and were talking about mandating rules to slow the aircraft down. The NMPRA then conducted intelligent speed tests with calibrated radar guns. We were flying at nowhere near 200 mph. So we managed to maintain our racing.

All of the foregoing was a result of idiotic speed claims.

You are totally missing the point. The last thing we as serious racers, or any other modelers, need, is for the AMA to actually believe that there are model airplanes flying at 200 mph. 450' away from crowds of spectators and other competitors. As I understand it the turbine guys have all sorts of AMA imposed restrictions upon their activity for basically the same reason as us. Idiotic speed claims.

So when you say that this is a toy, all for fun and that is the point, you are way off the mark.

Ed S

sandslx

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Horses ass called mr. Ed

I did a little research on you, and it seems the amount of information you have in pylon racing I could balance on the head of a thimble. Why don't you take a break from wagging your tounge in here and pencil Prinston in your calander for next year.

Justin Sands

Ed Smith

You did research on me? That was a waste of time, all you had to do was ask.

Judging by your spelling of "tounge" "Prinston" and "calander" it is not I that needs further education. I would suggest you take a grade nine refresher course. If that level of education is too high for you, ask somebody to explain to you, with simple words, how to use the spell check button on the Forums.

Ed S