iron eagel

CP,
I had gotten the impression that you were on dialup when you mentioned how long it to to download the Adobe Acrobat software, I know the frustration...
I used to use my home computer for work at times, and finally broke down and got a high speed connection via fiber optic line (fios) which is much faster than even cable, because what took me seconds at work took hours at home. So like I said I know how you feel about the frustration of spending hours staring at the computer while you try to do something, even uploading photos can be tedious working with a video is awful!
I am just lucky I have dealt with computers since they were introduced so I don't have to deal with the "experts" you deal with at most computer stores. BTY I was going to pm you about your issues with wave scope, (I haven't used the program) but have had similar issues happen with software and it usually came down to a few limitations which I will send you a note about in a bit. I know the last thing you want to do at this point is screw around with it but there are a few things you can try that might help.
Now back to the original reason I was replying to your latest posts.
Satellite DSL is basically how satellite tv itself works. It is the computer in your receiver which has a two way link to the computer in the satellite to transfer the data that is converted to the tv signal and output to your TV/VCR. The same type of breakups will occur with satellite DSL but typically just slows the data transfer between computers is my understanding, if there software protocol for file transfers is set up right.
My only kick is the high price of a fast connection,I was paying under $20 a month for dialup.
There isn't a lot of options as far as satellite DSL the company which ran direct tv used to have to have a service that was called direct PC but now I think Huges Net is about the only option. As far as the install it is much like satellite tv dish, cable to the box/modem/router, then data cable to the computer (your computer has to have a network card).

combatpigg

My Feedback: (3)

Paul, thanks for all the help you offer!
Here is a link to a couple minutes worth of listening enjoyment. ...[link]http://www.youtube.com/watch?v=QdTrm2yBWhU[/link]

vicman

My Feedback: (10)

It sounded great Chuck! Next time try to put one pass on film though.

Gravityisnotmyfriend

My Feedback: (2)

We've been doing something similar every year at SPADfest. We have a speed competition with a kind of gentleman's agreement that no high dollar engines are entered.

I won the last one with a TT.46 spinning a 9X7.5 on a delta of my own design. My best pass (with a tailwind) was 141MPH. I think my average was in the 120's.

Side track aside - that is freaking amazing! 200+ on a plane that small has to be nerve racking. Nice flying! That sucker was screamin. I'll run it through WOS myself if you don't mind - but it sure sounded like over 200.

Mike Connor

My Feedback: (5)

My 2 cents: (without bias)

I did make a request for another individual with more sophisticated software to look at the file. I will report back when I hear from him. Anyone else checking the last pass with Doppler please chime in.

When I first started looking at the sound file with WaveOScope I was concerned because the speed decreased as I checked different waves from left to right. This caused me to re-examine different files I have where I know the aircraft location to the recorder and the speed was verified with radar. It seems that the further away from the recorder you are when you pass, the slower Doppler says you are going. Just like a radar gun pointed at a plane flying by at a distance, the closer it gets the more perpendicular the aim is resulting in a slower speed read out. the highest and most accurate speed would be the first reading at the least angle. If any one can tear that theory apart please have at it. I noticed Highplains was here not long ago but probably wont be back for awhile.

My question to cp is how far in front of the camera did you pass?

I calculated an in flight rpm of 25,500+ rpm. Listening to and checking some f3d wav files I have turning 30,000+ rpm, there may be more to be had from this engine.

I do not like to use the first wave when checking speed because of the margin for error but because of this situation I did while being very careful to place the lines in a precise manner. Adjusted for temperature, is it possible there was a 3 mph tailwind?

smoknrv4

My Feedback: (11)

Sounds incredible!

combatpigg

My Feedback: (3)

Mike, it's hard to say from memory how far away the passes were, but they were as close to my body as I liked at the time........
Usually around here, the wind is variable and I'll bet gets stronger the higher up you go.
There was just a breath of wind that day.
The results of several 660 foot passes clocked with 2 helpers on cell phones is what I've used in the past. I've seen unbelievably consistant times pass after pass of planes in the 150 mph range. The timers have a foreground and background object for reference. What works in the foreground is the corner of a car's raised hatchback, plus it gives your helper some cover if the plane gets a mind of it's own.

GINMF, that's smokin' pretty good with those SPADS!

iron eagel

Once she cleared her throat, what an awesome scream!

MJD

My Feedback: (1)

It is an issue to consider - I notice on the leftmost traces one snap step or pixel or whatever, is several mph.

I tend to look at this as verification that the aircraft was in the 200mph regime, and that the HowFast data is therefore believable. I set lines over and over again on these traces, and consistently came up with 200-205 numbers.

MJD

combatpigg

My Feedback: (3)

The right thing to do would be to keep tweaking this set up and get a fast enough run to remove all doubt [8D]. This was only the 4th run on the engine and 2nd prop tried so far. It's hard to believe that the FAI dudes run these things even harder! The Dutchmen had a pylon plane do 209 recently?!?!

I'm impressed that the HowFast can be as accurate as it is for such a little contraption. It gives you a measure of some kind of what you are doing out there as you play with tuning and props. Removing those "gun tubes" probably sped the Screamin' Demon up a little, though.

I lost a little confidence in the Wavoscope method after reading a .15 powered plane that runs a 7x5 prop. The lines read 150-160 mph and the plane in real life is probably doing 90-100. I used the same set up with the video cam on the roof of the car, aimed into the distance. I tried several portions of the video and they are all reading way too high. The lines on the graph are nice and clean, too.

mk1spitfire

At what point (minutes/sec) into the vid was the 200 achieved?

I think for dopler to be super acurate it must fly overhead

combatpigg

My Feedback: (3)

The wave looked at is the last pass before it shut down. The other passes don't look as good.
You can hear the rpm jump a little at the end.

Mike Connor

My Feedback: (5)

I used the last pass before it shut down as cp said. I agree totally that very close is ideal for accuracy or you get a Doppler parallax (lack of better word)type effect.

I did check a couple of other passes and they were slower.

HighPlains

My Feedback: (1)

I guess I just read your post Mike.

You are correct about your theory. Not only would the lateral distance from the recorder make an error, altitude when making a pass would also skew the results. The result from a recorder will be within two percent if the angle is under 7 degrees. Which is rather difficult. Same for radar.

CP's method of cell phones could be pretty good, and better the longer the distance. While human reaction is limited to about .25 seconds, it is within a couple of hundredth when the observer can track an object to a gate to start a clock. However if the first guy tells the clock holder to start a watch, and then the second stops it on observation, then you have the problem of the 1/4 second of error. Having both able to directly control the start/stop of the clock would be pretty accurate over 660 feet, with about a 2% error. So 204 could measure 196 or vice versa.

One of the reasons that the AMA has no rules against prop planes doing 200 is because it is seriously difficult to do with IC power. With high power electrics, not so difficult - so they may respond to that one of these days.

Mike Connor

My Feedback: (5)

Thanks for your thoughts HighPlains.
For best results with Doppler you could put the recorder on the far side of the runway and do a very low pass over it. As far as my cell phone, the couple of times I was talking to someone close to me I noticed a delay between hearing them talk in person vs over the phone. Do all cell phones have a delay?

HighPlains

My Feedback: (1)

Well, the speed of light is 1 foot / nanosec, slightly slower in atmosphere.
A nanosecond is 1 billionth of a second. A fairly long period of time for electronics. A few years ago I calculated that the sun produces as much energy as the entire world uses every year in the time it takes light to travel 6 inches.

But when you start going through filters inside of communication devices, it would impossible to know and somewhat difficult to measure without intimate knowledge of the entire system. Cell phones have pretty amazing filters to cancel noise. But that may lead to significant delay.

For that matter, you get a slight trim shift in the RC control system from when it is approaching the pilot to going away.

iron eagel

Proof we should all be using solar collectors a lot more!

HighPlains

My Feedback: (1)

I have 7 million sq ft of solar collector.

combatpigg

My Feedback: (3)

There isn't a 2 way conversation, the guy at the finish line is holding the stop watch and remains silent. The guy at the starting line tells the timer when to start the clock with a short countdown, like...ready, set, go.

The only real skill required with the stop watch method is being able to talk two helpers into risking their lives so I can clock my toy plane.

Mike Connor

My Feedback: (5)

that should keep the ol house lit up. [X(]

Mike Connor

My Feedback: (5)

It seems the bottom line is that doppler would show slow, not fast. I am convinced this Screamin Demon has hit 200+ mph. CP is now a Delta God. [X(]

combatpigg

My Feedback: (3)

Mike, just think........you designed a wooden, open bay plane, for less than $100 with covering, delta no less....that did 200.....[8D]

Some time ago a guy blew in here and claimed that 200 was only achievable with CNC molded wings and planes of high aspect ratio. I told him then that I felt 200 was doable with a built up wood plane and could be done for $100. At the time I had already seen my scratch built DD with the Nalson FAI go "very fast"...with just a covering sag type airfoil. This was a few summers ago when I first got the engine, but never clocked the plane before the engine got fried. I ran it then on 5-10% nitro with the $4 APC 7.2 X 8.6 sport props. After the runs the engine smoked and you could hear the metal creaking as it cooled down. All the screws would be loose.

MJD

My Feedback: (1)

This true, the parallax error only produces slower readings, never faster. I thought I pointed this out days ago but I guess it was in a PM to CP. So you never have to worry about inflating readings via location of the recorder, and the subsequent heckling that could result. So with respect to recording Doppler shift, the closer to the recorder the faster the reading and the more trustworthy.

I went over CP's data maybe 15 - 20 times with different resolution, carefully picking the center of the pixel blocks on both traces, that kind of thing. I consistently came up with readings in the 200-205 range.

The MkII SD design is coming together nicely, I intend to label it as "a real 200mph aircraft" or with a similar sentiment. The MkII is redesigned to make it rear-intake compatible and to locate the tank over the CG. I'll consider stamping it approved right away if the SD65 comes back from the first flight attempt whole..

MJD

combatpigg

My Feedback: (3)

The new crop of .60 and larger Screamin' Demons should blow past the 200 mark if the little stuff like prop work and tuning gets done. This could be a golden age of 200 mph deltas with all the big Picco and occasional OPS engines I see being sold new for pretty low prices. I'd jump on borad, but have to call enough, ENOUGH with the toy collection and all the clutter it creates behind the scenes. Gotta do some housecleaning first and sell off some stuff that just collects dust. Anything with mouse turds in the fuselage is a good place to start.

MJD

My Feedback: (1)

A glider fuselage full of mouse turds sounds like a rain stick when you tilt it just a little bit. Kind of soothing actually. How about a 6" radius chunk eaten out of the TE by mice, does that count? I have one of those too.

CP, you have done your duty to the world of RC deltas and should feel no pressure to up the ante. My job now is to make it easier. I have the plethora of DF engines on the market firmly in mind with this project. And the speed designs.

It's interesting how things are so perspective based. I flew the SJ .50 Demon yesterday on a 9-8 for curiosity. I thought it was slow as molasses and was getting bored but the two fellows that came out with me said it was the fastest and wildest thing they had ever seen. It was probably down 30mph from where it was at with the clipped pylon props, though it certainly launched more easily. And much more able and wiling to horse around at part throttle.

Some peckerhead I know just scored a NIB OPS Speed .65 and pipe for $140 this weekend, and it wasn't me.. [X(]

MJD