Dustflyer

My Feedback: (13)

Just wondering what you other guys think about this. As you probably know I fly a Dust with a high-torque Jett FIRE 50 and MACS Quiet Pipe. It turns an APC 9X10 at about 15,700 on the ground. Lately it's been running lousy. I get the rpm on the ground but it just doesn't unload in the air like it used to any more. I've been using an Enya 3 instead of my usual KB 1L plug but I can't imagine that having anything to do with it. I think I might have burned the engine up pushing it too hard.

I asked Dubb Jett what kind of engine I should drop in if I wanted absolutely the fastest Diamond Dust on the planet and he said forget the Jett 50 and go with the QM-40 turning one of those little pylon props at 25,000 plus.

What do you engine and pylon racing gurus think about that?

I have some short but sweet MPEG video (only 270 kb) of my Dust on a high speed pass and another of the launch. I'd be happy to e-mail it to anyone who wants it. I'd love to know how fast you guys think it's going.

Edgar Perez

My Feedback: (13)

Please email the videos to [email protected]

Thanks,
Edgar

JohnVH

My Feedback: (38)

OK, OK, SO, how fast IS it, I know you know.

Ill guess,

218mph?/ hehe

Dustflyer

My Feedback: (13)

John,

I wish I had some good info but it looks like there are some problems with the EMS-Jomar stuff.

For starters the rpm logger reads 34,000 peak all the time, even on the ground. So much for that.

You've seen the video of my Diamond Dust. Does it look like it's going 138 mph to you? Something is a little goofy with the airspeed logger too.

Looks like I've got some investigating to do.

ChuckAuger

My Feedback: (12)

Just doesn't really matter...to me anyway. I know mine is right speedy. Dave Shadel said a Nelson FAI would out-turn the engine I run by a couple thousand RPM, but I just won't spend that kind of $$ for a Dust. So I am happy with whatever I am getting. I tach 22K on the ground, my engine makes its peak HP at 23K, so when it unloads it should be right in the power band. I get a bit more in a vertical dive...but I just looked inside the engine and it looks like new, so I am happy with the R's.

You guys have fun!

miderror

Dustflyer,
For the fastest so far it was a Nelson FIRE/FAI set up to
run on 65%nitro. My buddies in AU calmed 256mph.

If you want to stay with Jett look at the RR40 or Fan 40.
Dub will set it up to run as hot as you like. Just remember
the more perf you tune in the less life of the motor. Don't
get something for nothing.

I thought you said you didn't want anymore speed than you
already had?

Need a little more mph to get that same rush now days, ah?

Dustflyer

My Feedback: (13)

miderror,

You've got a good memory, I did say that! Problem is I think I might have burned up my engine, it just doesn't unload in the air like it used to. I get the 15,700 on the ground with the 9X10 but it just doesn't scream in the air like it used to. I'm seriously thinking about a new engine so I figured I might as well go for it.

bl10

For absolute hp you would probably want a Nelson FAI engine and pipe using a Q40 head. Using 15% Nitro you would have to prop it to turn 26 to 29 K on the ground (hp peak will be somewhere around 31K). To turn this kind of RPM you would need about a 7 in dia x 8 pitch FAI or cut down Q40 CF prop (do not try to run a standard small sport prop at this rpm. It will throw the blades). I have no idea what the drag of a DD or Wiplash is so assuming the high rpm small prop will pull the plane it should be a barn burner. FYI we get about 225 mph from a Q40 on a long shallow dive to level (about 180 to 190 on the course). The FAI engine has a larger intake, larger crank passage, rear exhaust and full tuned pipe as compared to our Q40 engines with tuned muffler. Both engines use the same sleeve timing (200 degree exhaust and about 134 degree bypass and boost timing). You should note these engines do not have a carb, we use a fuel shut off to stop them. They also are not noted for long life, most of the heavy hitters change the top end between 50 and 75 runs. (some change rods at the 20 run point). Jett is in the process of developing a new FAI 40 and there are a couple of European engines which are probably stronger than the Nelson. If you choose to try the Nelson be prepared for the ride of your life but also the attending problems and expense.


Barry

BruceDana

Why not measure the speed of your plane and fly it through a speed trap and video tape the flight(s). From the tape, you could time the pass repetitively (Rewind/Play, repeat) to get a good average time. Distance over time = velocity

When filming, be sure to shoot from midcourse and a fair distance away (helps camera person track the subject, and reduces parallax). The course should be well marked (so it shows up in the image) and the plane’s a contrasting color from the background (so it shows up too).

Don't bother to convert to PC video capture. Unless you can guarantee 1) the frame rate of the capture is exact, and 2) no frames get dropped and 3) you haven't a berated your time, then don't rely on this method. I have seen some exaggerated results as a result of insufficient controls over the capture/conversion process already.

Dustflyer

My Feedback: (13)

Originally posted by BruceDana
Why not measure the speed of your plane and fly it through a speed trap and video tape the flight


If your filming point is between the two timing points you would be viewing them from an extreme angle. How would you know when you are passing directly over the timing point?

BruceDana

I said " shoot from midcourse and A FAIR DISTANCE AWAY (helps camera person track the subject, and reduces parallax"

I meant that FAIR DISTANCE AWAY to avoid the extreme angles.

BruceDana

That didn't come out right...

sorry

BruceDana

The camera should be far enough from the course to avoid the high oblique angles.

Dustflyer

My Feedback: (13)

If you could get far enough away it just might work.

I wonder if there is some sort of mathematical correction that could be applied if you knew the angle and distance from the timing points?

BruceDana

If you know the length of the flightline and the distance you are from it would be solving triangles...

Cactus.

My Feedback: (1)

i've done this at a display, i sat at the back of the field with a stop watch. tho only one pilot would fly over the points and give me constant results.
i have a Doppler effect speed measure program you could use, i've never had the chance yet. you can use it on the field with a laptop pc and mic, or even play back your video to get the speed.
i hear it gives you a graph, and you move your cursor over the peaks, i cant see this being toooooo exact, but its better than the thing your discussing right now.
I can send the 2 zip files my E-mail if you give me addys

miderror

The Dust where fun with the hot set-ups but I saw a different
world when I started racing Q40.

All the info bl10 posted is the type of things you need to look at
if you want the fastest DD.

AVSPhoto

My Feedback: (20)

I had a dust with OS46 ducted fan, OS Pipe, running 8x9 apc on 30% blue thunder fuel........when set correct would burn a glow plug at end of 3 1/2 minute flight (KB-1L). Tached 21,000 on the ground, was clock by radar gun at 209MPH what a rush, plan how to fly it, lots of verticals!