Welcome! Log In Create A New Profile Recent Messages

Advanced

Berrien Springs news

Posted by Scotty 
Berrien Springs news
September 14, 2012 07:06AM
....is there a way to learn about what is going on at Berrien Springs? Is anything being posted in the way of updates, presentations etc.?

Apologies if I have missed something already posted or planned.

Thanks.
Re: Berrien Springs news
September 17, 2012 08:15AM
September 17, 2012 Dear Phorum participants. We all survived the Berrien Springs event. Fifty people showed up, speeches were made, information was displayed, engines were shown, vehicles were run. I appreciate the optimism shown by Scotty to think that I am technically conversant enough to first of all record and organize anything and second of all to post it somewhere. I will take that as a compliment, clearly made by someone who has never looked me in the face. I understand that not everyone can afford the time and money to travel to the Heartland of America for these meets and appreciate all of those who did make it here. We are lucky to do what we do and someone might write up a report. It has not happened much in the past. Tom Kimmel
Re: Berrien Springs news
September 18, 2012 05:21PM
okay, Okay, OKAY, enough already. I am writing up the meet for the next Bulletin so all you need to do is be sure you are an SACA member and you can read all about it. One thing that will not happen is transcribing and printing the entire text and photos of all the talks in one issue. I think I do have enough to give a list of topics, speakers, cars and Time Trials results.

I really enjoyed the meet and hope you enjoy the articles it generates. As Tom knows so well and tries repeatedly to tell everyone, being there is the best part.

Karl Petersen
Re: Berrien Springs news
September 19, 2012 06:19AM
I have posted a new video on the youtube SACA channel. It shows my presentation of the Tragster data recorder installed for the meet as well as the results I found out after the time trials. If you saw the presentation at the meet, you might want to skip to minute 8.

[www.youtube.com]

Roger
Re: Berrien Springs news
September 19, 2012 01:48PM
Hi Roger

Depending on the Arduino you are using there are usually several ADCs that can be used. You can get higher sampling rate by using multipal ADCs in paralell. At least the hardware is able to do so. There are several digital storage O-scops based on ARM Cortex processers on the market. The specs for the ADCs on thoes processors is half the sample rate of the O-scope spec. Obvious they are using two ADCs per chanel.

Your data is interesting and you analysis I think is right. One thing to be noted is that the wave shape is corosponding to time or vary close crank angular position not liner piston position so comparing to an indicator card it is not the same.

The high frequiency observed on opening could be a number of things from unrelated electronic interface noise, the line to the transducer or real fluctuations in the cylander. It's not uncommon to have that problem be in the temperature isolation line to the transducer. If it is in the line to the transducer it would show up when the RPM matchs the line length harmonic. Also the in the S.E.S. papers there was simuler fluctuation observed in the inlet passages. Stan used a tuned port having tubes to change the harmonics of the inlet to increase pressure as the valve opened.

The poor exhaust evacuation is a problem we have addressed here before. I brought up the idea of using an expansion chamber on the exhaust like was used on twostroke motorcycles. Your data shows that a lot could be gained applying tuned port and expansion chambers to a steam engine.

Great work Roger.
Re: Berrien Springs news
September 19, 2012 03:29PM
Thanks for your input Randy. I was all excited to use the ChipKit Uno as it is suppose to be much faster and would meet all my needs. And it is lots faster but here is the problem. I would get 10 K points/sec but only about 20% of the time--it was like it was resting the other 80%. So obviously it didn't work. I asked on various forums and nobody could explain it. The standard Uno has a similar problem but not as severe. In the data I took, I got a point every .89 msec but every 1.88 seconds, it delayed for 2.62 msec. Very strange.

I do have a Picoscope that I like but it requires me to carry a computer on board and there isn't any room for it.

I do understand about secondary motion and include it in my analyses as I mentioned in the article in the Bulletin.

I have ran many different engines from 250 to 3000 RPM and never saw the harmonics before but I have typically had a good size accumulator just before the valve and it was in the boiler in this installation and separated by one foot of 3/8" flexible SS hose so maybe that was the difference--heck it could even be the flex hose instead of solid pipe. I ran out of time and interest to really track it down but may visit it again if it shows up.

Roger
Sorry, only registered users may post in this forum.

Click here to login