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Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Really want to go fast??

Old 02-20-2007, 08:38 PM
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Kmot
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Default RE: Really want to go fast??

If you personally know the guys selling the engines, that is one thing. I do not. And an engine with 20, 40, 50 'runs' on it can be toast. Especially from ebay. That was my first reaction.
Old 02-20-2007, 08:43 PM
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proptop
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Default RE: Really want to go fast??

DHG and Ed, that is re-assuring, thanks [sm=thumbup.gif]
Not exactly sure what you mean Bob but I think I have a clue...would you care to elaborate?
Old 02-20-2007, 08:51 PM
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Default RE: Really want to go fast??

What about maintenance...? How long will Nelson support these "old" engines? I wouldn't mind going for a couple of these things, but only if I can get parts for them in the near future.
Old 02-20-2007, 10:10 PM
  #29  
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Default RE: Really want to go fast??


ORIGINAL: daven

The three sellers on there are all very well known in the pylon world, not that that means anything, but I wouldn't hesitate buying anything from them. They are obviously upgrading their equptment.

The user "snoogi" or something like that is the wife of a 6 time National Champion, and his engines are very well taken care of and serviced by Dave Shadel.

I know I would have absolutely no hesitations in buying from any of them.

I'm keeping my 3 paper weights for practice

Since you know who is selling them you can buy with confidence. And now more of us know too.

And in todays world there are too many who use ebarf for less than honorable dealings.

I did not read all the auctions and did not see the sellers comment about serviced by Dave Shadel.
Old 02-20-2007, 11:11 PM
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Default RE: Really want to go fast??

Ok Tom,
The following three graphs are for un-accelerated flight. Flight at 1 G.

The first graph shows the relation of Parasite Drag Vs. Speed of the airplane. This drag goes up with the square of the airspeed.

The second graph shows the Induced Drag, which is inversely proportional to the speed squared. Go fast and this drag of producing lift goes away

Put the two drags together, and you end up with the “J-Curve” At the minimum drag point at the bottom of the curve, the airplane needs the lowest amount of power to fly. In a full size airplane, this is where the best glide speed is (assuming no wind), and the best lift to drag.

Most flying is done on the right side of the curve. But the left side of the curve is useful for controlling glide slope on a clean airplane. Here, the elevator works backwards, if you increase the elevator the airplane comes down faster while flying slower. There is no flair on this side of the curve, so you have to lower the nose before landing so you get back to the right side of the curve for a normal flair.

By knowing how to recognize and developing the fine touch needed to uses this mode of flight, you can drop a very clean airplane into a very short runway dead stick.

The other little trick used by racers is getting the airplane on it’s wheels, then pushing down elevator to increase the aerodynamic drag if you end up too hot. You can scrub off a lot of excess speed in a very short distance with an airplane with conventional landing gear.
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Old 02-21-2007, 10:26 AM
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Default RE: Really want to go fast??

The other little trick used by racers is getting the airplane on it’s wheels, then pushing down elevator to increase the aerodynamic drag if you end up too hot. You can scrub off a lot of excess speed in a very short distance with an airplane with conventional landing gear.
I would agree Bob, the muffler spraping across the runway creates a lot of drag..
Old 02-21-2007, 11:45 AM
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Default RE: Really want to go fast??

ORIGINAL: diggs_74

The other little trick used by racers is getting the airplane on it’s wheels, then pushing down elevator to increase the aerodynamic drag if you end up too hot. You can scrub off a lot of excess speed in a very short distance with an airplane with conventional landing gear.
I would agree Bob, the muffler spraping across the runway creates a lot of drag..
Oh you beat me to it... [&o]

So does the vertical fin if you go right over.

Has anyone succesfully done this on 2 wheel gear on a plyon racer? Everyone around here flies from grass so never seen asphalt pylon landings. What do I know, but it seems to me the hardest thing to do on grass is stop 'em from nosing over.
Old 02-21-2007, 12:00 PM
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DHG
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Default RE: Really want to go fast??

In Colorado we rely on the dust and gravel hitting the leading edge to slow them down ... then it's a simple matter of steering between the thistle bushes and aiming for a prairie-dog hole to make that final stop. [:@]
Old 02-21-2007, 12:05 PM
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Default RE: Really want to go fast??

It really depends on the grass. If its thick, they don't roll so good and flip over. My previous local fields grass would easily let them roll out before stopping and flipping. Then again, it depended on how fast you came in, and if it hit a rough spot on the field.
Old 02-21-2007, 12:25 PM
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Default RE: Really want to go fast??

The worst part about landing on grass is that if it starts yawing a little it will do the "tail wag" and possible crack the fuse right behind the canopy on my Dagos...
Old 02-21-2007, 01:15 PM
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Default RE: Really want to go fast??

Our field is kept cut nice and short...(thanks flyinbr ) but it's a bit bumpy and has whoop-de-doo(s) in it...

Instead of a Zoomer, now you guys got me thinking about building a Napier or maybe the AJ-2? (I mean, ya might as well go for it, aye!?)

Bob...when you mentioned J curve, my mind flashed on "lift to drag ratio" and I guess I was right, but I haven't cracked a book on that stuff since the early 80's...(good grief, that was 25 freekin' years ago already![X(] )
Thanks again![8D]

When you mentioned using down elevator to scrub off speed, first thing I thought was when the muffler starts digging in, that sure will slow things down!

We flew off Griffiss AirForce Bases 10,000 X 200' concrete for 30 years, and I wouldn't think twice about using a straight venturi over there, but we got booted off Griffiss in '05 due to big business moving in (the base closed in '95-'96 and now "Empire Aero Center" is overhauling 737's, 747's, DC-10's, etc. etc. over there...they just got a contract for Virgin America, and Jet Blue (hope that one lasts???)
It took a little getting used to flying off grass again, and I guess 800' just seemed short when I remember the concrete?
Old 02-21-2007, 01:20 PM
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Default RE: Really want to go fast??

We land them on grass and on pavement. For grass, it's usually not needed to push after touchdown, as the grass slows the plane down pretty effectively. On pavement, we sometimes push on the stick after landing to force the muffler into contact with the pavement as a brake. This works with Q500 as well. For those of you who don't race, you do have to set up your prop so that it stops in the horizontal position, as these engines are landed at dead stick, since there is no idle.
Old 02-21-2007, 03:31 PM
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Default RE: Really want to go fast??

I personally don't like the muffler drag brake method as it can be rough on muffler bolts and firewalls. The problem is, you don't normally find out it was rough on the muffler bolt or firewall untill the next heat when you take a zero!
Old 02-21-2007, 05:15 PM
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Default RE: Really want to go fast??

I don't really like to do it either but it's better than watching it roll down the runway for 400' becuase you came in a little hot and you don't have enough down throw to nose it over.. Don't ask me how I know..
Old 02-22-2007, 10:12 AM
  #40  
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Default RE: Really want to go fast??

Agreed with Ed here......

no issues at all operating a QM40 out of a tight grass field... My field is grass, about 400 feet runway. Take off takes about 25 feet, landing is easy, you just have to learn how to land the plane. It is a different technique. As differet as landing a Hobbico Trainer and Landing a 25lb Corsair. Not hard at all .... but with practice, you can put the plane right at your feet.

In fact, the grass helps - deceleration on touch down is pretty quick. On pavement, you can get a roll out of 100-200 feet in some instances. Been there a few times coming in just a little bit too hot .... trying to nose the thing over - the muffler makes a great brake

Somewhere last fall/summer I posted a link on here to one of my QM40 demo flights at an airshow. Shows exactly what I am talking about here. Velocity and energy control is important for landing. Know when and where to bleed off energy. Use the rudder to keep the nose DOWN in the turns and to help the plane turn. Also, when the plane does slow down, control response will be slow - you want to be lined up with the runway, and only subtle control movement is desired. Correct landing gear placement will help ensure the plane does not bounce.

I think this is the link
http://www.lcrc.org/Tony/Videos/2006...ng%20plane.wmv
Old 02-22-2007, 03:39 PM
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Default RE: Really want to go fast??

Nice video Bob.

Motor was really signing my tune.

Mike

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