New projects for this year.

[lohring]

No, i dont think i need a centrifugal clutch, it is easy to start and runs fine on idle. After the pull i can let the engine back on idle or stop it while the flyweel is spinning.

20mm one way needle bearings can be used over 20k rpm, my flywheel does not spin faster than 6-7k rpm.

The one way bearing have never been a problem

You need to have a surface harder than 50 hrc for the needle bearing, i used hardned 2541 steel.

Yes i do

Thanks. I think your secret for success with a one way clutch is the low flywheel speed. My friend's dyno was direct drive as are the ones I've built. His turns over 30,000 rpm with a 6 cc nitro engine and we've run up to 25,000 rpm with gas engines. The belt drive is a good safety fuse if an engine seizes. In all it's a very nice setup.

Lohring Miller

 

[steve wood]

I would love to have info and instructions on how to build one of these.

 

[simen gjørstad]

i used this page for information

http://www.tdkmotorsports.com/dyno.htm

Did the machining at my job

 

[Craig Murphy]

Not sure how I missed this tread...... good read people.

 

[dwilfong]

Simen what belts and sprockets are you using?

 

[simen gjørstad]

dimensions or from what manufacturer?

 

[dwilfong]

dimensions or from what manufacturer?

Both

 

[simen gjørstad]

It is a long time since I bought it, cant find the site.. 15mm wide.

But this will do also

http://www.beltingon...generation-258/

Dont use any cheaper belts... They will break... only use the best.

Edit, think it was from elfa, site from sweeden.

 

[dwilfong]

Thanks Simen so thy are timing belts.

Tried to make a gear drive with them but the line up with two belt and a jack shaft was a pain to make them run strait.

This is a much simpler setup. Also the sharp loading from launching the boat did not help any.

 

[Terry Keeley]

These guys are great for belts/pulleys:

http://www.sdp-si.com/eStore/CoverPg/Drive_Components.htm

 

[dwilfong]

These guys are great for belts/pulleys:

http://www.sdp-si.com/eStore/CoverPg/Drive_Components.htm

Great link Terry!!

Every thing needed to make the drive in one place.

 

[dwilfong]

I have bin pondering the Dino build with all the info that has bin put forward By every one.

I like the mag break set up and also like the inertia set up.

Maybe a combo of both to make a steady stat to make extended running time for longer test sessions?

Was thinking a Cart disk break rotor with mags to load it driven by the belt drive?

 

[lohring]

For your first dyno go with an inertial dyno and professional software. You'll get a tool that isn't an experiment in itself and you can spend your time testing engines. The details on our dyno were reported in Model Engine Builder issue 15. I still like the Performance Ttrends dyno data logger package. Go with the professional software. The graphing is worth it. The Datamite Mini is fine for our use. You don't need much beside the rpm function. We entered weather data manually, but the weather station option would be nice. I would consider the optical rpm sensor for high rpm operation. These guys have a spread sheet to calculate flywheel inertia. Watch the flywheel stresses. Machinery's Handbook has a formula for that.

Lohring Miller

 

[dwilfong]

For your first dyno go with an inertial dyno and professional software. You'll get a tool that isn't an experiment in itself and you can spend your time testing engines. The details on our dyno were reported in Model Engine Builder issue 15. I still like the Performance Ttrends dyno data logger package. Go with the professional software. The graphing is worth it. The Datamite Mini is fine for our use. You don't need much beside the rpm function. We entered weather data manually, but the weather station option would be nice. I would consider the optical rpm sensor for high rpm operation. These guys have a spread sheet to calculate flywheel inertia. Watch the flywheel stresses. Machinery's Handbook has a formula for that.

Lohring Miller

Lorhing how you making out with yours?

Have you made some test with the load cell?

 

[lohring]

I'm having problems with my beat up Eagle Tree recorders and sensors. They've had too many speed controls blow up around them and too much water through them. I'm planning to buy a new Performance Trends data logger as soon as my boating budget recovers. Otherwise, it's mechanically fine.

lohring Miller

 

[dwilfong]

Here is the start of the flow box. Have a reusable filter to put in the box sitting in a plastic tub.

This will catch the liquid and let it be removed in the tub after the run.

Will get a rubber mat and glue it to the table to make the seal.

Have all the tubing to make the water gages.

For the first test will use the shop vac hooked to the 2 1/2' tube on the one end.

The working end will have different adapters to hook to various things.

All and all not including the shop vac less than $100.

David

 

[dwilfong]

Why not just silicone the lid on and add a drain cock

You dont want to loose the seal and have liquid go everywhere

That is a good idea!

I did a test and it seals so good to the table with no seal that you can lift the table up and it holds it suspended.

A plexy glass top with a seal would do it. the suction will make it seal.

Easy enough to just pore it out when done.

There we go works perfect.

 

[dwilfong]

Well I used my flow box for testing tonight on my new VAC carb setup.

I use the BV flow meter to pressurize the tank and use the CMB needle as a air bleed. the meter is set at 220 witch is 4 Psi to replicate pipe pressure at full throttle.

The BV needle is preset to 33 witch is my base setting on my large engs.

With the 5/32 brass tubing as the spray bar I can move it in and out of the carb boar to see the atomization pattern.

I tried a small hole in the spray bar at a point half way between the end and the side of the boar.

It was very interesting in how the spray bar acted. It started making a noise as you moved it to different point on the boar. a real high pitched vibration as the air mixed in the spray bar with the liquid.

Moving the hole to different locations in the boar changed the frequency of the vibration and the mist.

You can tell when it is perfect.

Also put a slot in the back side of the bar at the end to fill the boar with mist.

More testing to come. This setup works great for testing!!!!!

 

[Tim_Duggan]

Great work Dave!

"It was very interesting in how the spray bar acted. It started making a noise as you moved it to different point on the boar. a real high pitched vibration as the air mixed in the spray bar with the liquid.

Moving the hole to different locations in the boar changed the frequency of the vibration and the mist.

You can tell when it is perfect."

I'm curious to know if the behaviour changes if you alter the fuel pressure - just like if the stinger diameter on the pipe was changed. Is the spray bar config still optimised at the same position if the fuel pressure was changed? I guess I'm trying to say - does the carb optimisation have to be re-done if the pipe stinger is changed.

 

[dwilfong]

I will try different pressure setting tonight and see what the change is.

the pressure is a reference that I got from a posting that Jim Allen made in the past.

Would be nice to log pressure with the eagle tree.

There is a pressure sensor built in to the logger to get air speed. I can hook this up to the pipe tap and then use the BM flow meter to calibrate the readings in the live mode to see what is what.

will put this on my list of things to try in the future.

I will try different relation ships of the hole distance to the end of the spray bar also and see what happens.

The size and shape of the slot in the back of the bar I will change also.

You can see the plume of mist coming out of the bar real nice as the boar is lit up with all the light coming thew the clear box setup.

I will try the strobe light next as was recommended.I can put it right on the top of the box to light up the whole box.

This should be way cool.

Between the strobe and the music the bar makes I may go into a transcendental state and become a true Guru. :lol: :lol: :lol:

I have not calibrated the flow box yet for the 25 cfm plate. Just getting a feel for how it works right now.