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View Full Version : Telemetry, good or evil....



SpinB
12-15-2006, 12:45 PM
I have two questions about TM-ing aircraft performance data to the ground.

1. Does it create an unfair advantage for teams with disposable cash?
2. In regard to transmission format, is it straight RS-232/422 modulating the transmitter or some other PCM-type format? (I'll forgo my bit-rate
and band-width questions....)

I know Mr. Shelton and Mr. Destefani have used it for years with great success. I think it's a bonus to have extra eyes to watch the guages while the driver can concentrate on leaving minimum paint on the pylons!

morss
12-15-2006, 01:01 PM
It can be a two edged sword. Our first year with tel it was visable to crew chief hartz rep and cont rep. cont kept asking for more rpm (lower cyl pressure) hartz for less (keep blades in hub). next year only crew chief had data and only one was able to talk to me.
dave

Mluvara
12-15-2006, 01:56 PM
Racing is racing... whatever it takes to go faster at whatever cost. I was told when I was little that racing isn't for the broke.

The data is encrypted on digital links and sent via varying methods. Of course, I only know that for sure on the systems that I have built.

The bottom line is that if it is used to its advantage, one can save equipment, especially in the unlimiteds where parts are getting scarce. It's also a safety factor for the pilot. They should be looking out the window and not in the cockpit.

Michael

Bottom Rudder
12-15-2006, 01:59 PM
It is good.

A $10,000 telemetry system that saves a $180,000 engine is good economics. Racing is racing, and telemetry isn't outlawed, so those that can get it or buy it will have an advantage as long as they use it's power for good, and not evil...

B. Meistein.

SpinB
12-15-2006, 02:20 PM
No fella's, don't sugar coat it...my candy-a$$ can't take any more!

Mr. Michael, I read about your RCATS business and wish we could have aquired some of those bitchin' systems, you've developed, for Airdrop Research! It would have been a perfect fit in our 'Crash-test-dummies' !I've used the SoMat system before, but, they did cost a lot! MUCH success I wish on your endeavors!

Mr. Dave, I have the same problem with engineers that are TRYING to interpret TM stuff real-time! Definite advantage to limited access!

I suppose deep down, I new what the answers were before I asked the question!....Racing is Racing! Fly Fast, Fly Low, Go Left!!!!!!
(Anti-Clockwise for the British and Canadian friends....) :D

Thanks to all....

speeddemon
12-15-2006, 02:23 PM
We have a system similar to Mikey's that we use in the race boat. It is so sensitive and accurate, we can tell when the driver hits a bump or makes even a miniscule 'correction' in the turn or on the race course.

It certainly can be a 'tattle-tale' device if the driver/pilot screws up too.

Now in boat racing, the 'real time' part of it is outlawed....but it sure makes it cool to debrief after the race is over when you plug the card in the computer.

paintboy
12-15-2006, 09:29 PM
The cockpit of a racer flying 40 feet off the ground at 450+ MPH is an extremely busy place for a pilot. Telemetry allows the ground crew to keep tabs on the vital aircraft systems in stead of the pilot having to relay this info to the crew. Less tasking to a pilot. I think all racers should have it, as it may possibly save valuable equipment as well as a pilots life. If you are going to go racing, I am not sure I understand how this valuable equipment would be omitted from a racers list of equipment. yes it is expensive! But when you spend hundreds of thousands of dollars developing a racer or building one, how do you NOT incorporate one of these systems into your racer?
The reliability rate of these systems are foremost in my mind. Lets look at what happened to Dago Red. This racer has a telemetry system that oversees the engine and other components vital to the survival of the aircraft. Before the motor turned into a 2000 Lb paper weight, did Dan or the crew get ANY kind of indications the motor was going south? The ultimate demon that caused the catastrophic failure was a check valve, as I understand it, but as the motors temperature rose to the point of molten lava, what was the telemetry seeing? Could this failure have been avoided, or at the very least caught before serious damage was reached? What did the little black box see?
I am not the designer of telemetry systems, or a motor expert, but it seems to me, the one thing that could have saved an engine, didn't. But I think the positives out weigh not having one installed.

Dave

SpinB
12-15-2006, 10:34 PM
I am not the designer of telemetry systems, or a motor expert, but it seems to me, the one thing that could have saved an engine, didn't. But I think the positives out weigh not having one installed.

Dave

Well, from my point of view, Instrumentation has limits! Unless you place strain gage bridges, accelerometers or other acoustic sensors IN the engine case and ON the rods and crank, thermocouples or RTDs on the bearing surfaces....ad infinitum.....you get the point...you'd wind up adding 250 lbs of additional wiring, not to mention the utter impracticality
of slip rings for signal transfer......well, if ALL of this where done, it would be moot as, in reference to a previous thread..A LOT happens in 1 second in the life of a racing merlin!

Bottom line: it's racing, shiznit happens...fast! The devil IS in the details!

Mluvara
12-15-2006, 10:38 PM
I can't comment on what happened because I have not seen the resulting data nor know anything about the motors. Even if I did, it's not for public consumption. That lies with the respective teams.

I will say this. The systems work and they do tell you what is happening and what has happened. Having a system is one thing. Knowing what to do with the data it gives you is another.

Michael

Ken from PG
12-16-2006, 12:51 AM
It's UNLIMITED air racing...270 days to go!!!

Whiteside
12-16-2006, 11:59 AM
I'd better get busy or be left behind!
WW

SpinB
12-16-2006, 04:47 PM
I'd better get busy or be left behind!
WW
Well, Sir, if you can multi-task like a fiend and enjoy a high, out-side line,
it's not that important.....snicker,snicker.....
...Yaks on Attack...

440_Magnum
12-17-2006, 01:56 PM
The reliability rate of these systems are foremost in my mind. Lets look at what happened to Dago Red. This racer has a telemetry system that oversees the engine and other components vital to the survival of the aircraft. Before the motor turned into a 2000 Lb paper weight, did Dan or the crew get ANY kind of indications the motor was going south? The ultimate demon that caused the catastrophic failure was a check valve, as I understand it, but as the motors temperature rose to the point of molten lava, what was the telemetry seeing?

Dave

A good question, and I have no idea what the telemetry showed in that case. If it was a sudden failure so that the ADI disappeared instantly, the engine would have been gone before the guy on the ground could have even keyed the mic to tell the pilot of the problem. Even some kind of fully automated telemetry/control system that could send commands back to the systems without the pilot doing anything would still have limits to what it can detect and correct in time to prevent damage. As someone else pointed out, you can't put a strain gauge in every connecting rod bolt, and even if you could a defective bolt might fail without any warnings on the gauge.

Perhaps a better example of where telemetry might have saved an engine would be Rare Bear. I'm guessing the induction temps were over the limit for some time before the big blow.

fenceliner01
12-18-2006, 02:43 PM
A good question, and I have no idea what the telemetry showed in that case. If it was a sudden failure so that the ADI disappeared instantly, the engine would have been gone before the guy on the ground could have even keyed the mic to tell the pilot of the problem. Even some kind of fully automated telemetry/control system that could send commands back to the systems without the pilot doing anything would still have limits to what it can detect and correct in time to prevent damage. As someone else pointed out, you can't put a strain gauge in every connecting rod bolt, and even if you could a defective bolt might fail without any warnings on the gauge.

Perhaps a better example of where telemetry might have saved an engine would be Rare Bear. I'm guessing the induction temps were over the limit for some time before the big blow.



Here we go....

speeddemon
12-18-2006, 02:48 PM
Telemetry is for wimps. Guys like Chuck Lyford and Don Whittington never needed telemetry....they just shoved the throttle to the stop and let 'er go.









Of course, they rarely finished, but I try not to get confused by the facts.