Need some help. I am in the process of building the ultimate engine test stand and I need to find some data acquisition software that will work with my laptop and allow me to monitor cylinder head temperature (CHT), exhaust gas temperature (EGT), RPM (I know you know what that is) and any other engine related values. I want it to be able to interface with a laptop. This test stand will also have a force gauge installed on it to measure thrust.

Now before you go and tell me I am wasting my time and give me the physics lesson of a life time why it won't work - stop. I just want to do it, plane and simple. I already know the physics of it and all the compensation required. Just need to find this software so I can bring it all together.

Any ideas?

Thanks,

MHF

I certainly wouldn't say it won't work, it's done all the time in dyno rooms all over the world. I think you need to do some searching for home built dynos and the like. I know there are freeware versions of dyno software around that monitor most of the things you are looking for. I think Google will be your best friend at this point. Also search on data aquisition and I bet you find forums and lists that deal with it as a core topic.

Cool project, BTW. It sure beats speculating about things when you have the hard numbers at hand.

Mark

How about some pics. It would be nice to have a choice engine test stand.

For Instruments like temperature, try Omega.com. They offer the laptop compatible DAQbook data acquisition system.
They also offer load cells, a good way to get torque.

Mount the engine on the crankshaft centerline, on gimbals, and keep it from turning with a lever secured by a load cell (to measure force.) Force X the lever arm gives you torque, torque X RPM and you get power. Much more convenient than measureing thrust.

If you choose to really measure thrust, good luck. I think you would be better off without a prop, just a flywheel, and external cooling with fans & ducts.

Monitor RPM with a photoelectric tachometer (or rig a photocell or laser & use a frequency counter to get RPM output).

Humidity & Altitude compensation are somewhat more difficult, if you go that far. I can give you some help there if need be. If you want to do some machine work in the head and add cylinder pressure pickups, I recommend the Piezo units from Kistler. They sell charge amplifiers (to convert the signal into a calibrated output) too.

I believe I've mentioned about $50K (without humidity or altitude compensation) so far. Be sure to post your progress and document for the interested.

Best wishes,
Dave Olson

Hey Jetmech64,

I like your project, I've thought about doing something similar but can never seem to find the extra time. I am assuming you want to record the data to your computer, and not just watch the events on a computer screen. I recently purchased a data recorder for a bench I'm building that is a very good value as far as daq systems go. It is manufactured by a company called Innovate engineering and you can find all sorts of info if you google "Innovate DL32". The DL32 is the model number of their recorder and I believe it will handle all the channels you will need to monitor. They offer additional ad ons if you need more channels, I purchased the SSI4 to allow me to record what I need. I would suggest looking at their site and searching their "forum" for specific questions. Their software is very user friendly. You can both record the events and view them "realtime". The realtime is great as you can monitor what's going on by just looking at the readouts on the screen. Their software can be downloaded free on their forum....go get "Logworks 3" and play with it. You can also download the manual for the DL32 from their site as well....I looked briefly at mine and It sounds like the unit comes with a "probe" that will work for measuring cylinder head temperature....check it out to be sure.

Don't let "Scar" scare you.....you don't need to spend $50,000!!! This unit retails for around $500.00. You will have to purchase some extra sensors, but you're not looking at a huge expense there either.

I also disagree with his recommendation of running the engine without a prop, and just using a flywheel & cooling fans. If you're wanting to measure power you are going to have to put a load on the motor somehow. I feel a propellor is the best way as if you design it to use the propellor you can "dyno" different propellors as well. The flywheel design will work if you have a water wheel, inertia wheel, or an electrical means of applying load but this type of design could get the price into the "rediculous" zone.

Keep us updated with your progress!!!

Jeff

Check out performancetrends.com they have what you need to make everything you explained happen for relatively low cost. Low cost 4 channel data loggers, dyno software capable of torque arm managemant, sensors, thermocouples etc.

I have a similar project in the works however, mine is going to be a much more elaborate inertia dyno designed to test 50-200cc gas engines. I have used performance trends in the past to equip my nitro engine dynos.

BK
nitrodyne systems
www.nitrodynesystems.com

Use some pillow blocks and an axle for the engine mount so you can measure torque as well. Horsepower as well as thrust can be measured. Also add an airspeed pitot for the slipstream velocity for the ultimate propeller dyno. The only instrument you mentioned that would have least value would be the temp gage. I say this because these small engines cannot be damaged by tuning lean of peak like a much larger one will.

How do you measure horsepower?

Mark

I normally don't, but its very easy to do with a scale and tachometer. Im surprised that there are not dozens of people here with simple homade dynos.

You don't measure HP. You measure torque and calculate HP. HP=torque x RPM/5252.
Torque is in ft lbs.