Looking good, nothing quite like running the engine and seeing exactly what it is doing temperature wise!

Originally Posted by MadScientist

Looking good, nothing quite like running the engine and seeing exactly what it is doing temperature wise!

Thank you all for your help and input.

I am curious as the whether or not these readouts will take the vibration.

Originally Posted by ChemE

Thank you all for your help and input.

I am curious as the whether or not these readouts will take the vibration.

You are welcome!

I would be more worried about the thermocouple leads breaking.

Hi all!!

While waiting for the type k thermocouples to get in, I decided to convert one of the reverse rpm sensors to be able to give me a square output to drive an rpm meter. To do this, I am looking for calculations to see if I need a signal amplifier. Since the magnetic field supplied by the magnet embedded in the prop hub will generate millivolt level voltage, I wanted to verify that the old reverse DA sensor will work with the rpm meter I am getting.

Attached is a PDF paper explaining Hall censors and switches. Good reading for a rainy day!!!!! Also, if you can't sleep, reading this thing will be better than any sleeping pill. It is a straight forward explanation of how proximity sensors work.

Loaded a better quality video on the next post.

I started the engine and it was running very tough. Visible issues were:

1) One hot and one cold cylinder- Cause- Bad ignition. Changed ignition (Old one that came with the motor was bad) and the motor ran better.

2)On restarting, the right cylinder made a lot of smoke and was 10 deg C colder than the left.

3) When bringing the engine to 3000 rpm, it would run away. This indicated a leak of air from somewhere. RC brother GHoffman recommended testing with carburetor cleaner at idle and see if the rpm increased from a seal leak. This did not happen and the leak could not be identified. I replaced the original carburetor with a new one and the problem was solved as well as the temperature difference in between the the two cylinders.

A small leak was detected in my fabricated manifold: see picture. I will repair it this week.

I did not take the engine to max speed yet as I am not at all comfortable with the temperature and RPM measurements. I am waiting for the thermocouples from Chief Aircraft. They are American built and would feel better as to the quality.


Some low end vibration. The holders holding up the cans should be placed a few inches further back. I will do a vibration measurement when I have everything tooned up.

The needles were close to the DA recommended settings. Low end 1/8
turned richer.

DA150 Start up (5 min 49 sec)

Hi all,

Please feel free to use this DA 150 thread for any DA 150 issues you may have. I will change the thread name if you all like.

As always, please keep issues to the technical.

I have a couple of more posts on the braking in of the engine and I will be done. Also for carburetor adjustment there is a nice thread here:

https://www.flyinggiants.com/forums/...read.php?t=427

Some time ago, I purchased a Mr. Funnel. I use it to pre-screen the gasolene before I mix it with oil for storage. I think it is an excellent product.

Has anyone had experience with this filter? The filter I have can do 3 gallons/minute and remove water as well as dirt. The filter is 5 micron and can easily be cleaned. The only issue is that you have 3 oz unscreened at the bottom.

mr. funnel fuel filter (1 min 17 sec)

My initial start-up of the engine was successful, however when reaching 3000 rpm, the engine would run away. This was indicative of an air leak.

I replaced the original carburetor with a new one with the runaway condition being fixed, and i am only able to get 5600 rpm max on the engine. The needles are set perfectly as the idle rpm is reproducible 1200-1250 and the transition to high rmp is smooth with very little to no smoke coming from the exhaust. I should be able to get to 6200 rpm + with the 30x10 prop I am using to break in the engine.

I think that I have a fuel mix problem.

I have acquired a 500-500 walbro tool repair set as well as an OEM Walbro 0-60 psi pop off pressure tester (57-11-1). I am trying to ascertain the cause of the leak in the original carburetor as well as the internal needle setting to see if there are any differences.

If the internal needle sticks up into the diaphragm, a rich condition exists.

I will also look to see if there is a shaft problem on the throttle so that no air is leaking in. The least issue is the ignition, but I will leave that to last.

Any input would be appreciated!!!!!

Whats the pop off pressure, metering needle lever height, have you tried open header?

Just connected my new $140 OEM gauge and it is leaking. Go figure. The Cheep knock off is $30, and here I go and get the real deal and it stinks. The work will have wait until I get a replacement.

Hi all,

It has been a while since my last post. It has been a busy summer and spring.

A new pop off gauge was purchased and it is working (amazon $56)
I repaired a damaged ignition since it was firing on one cylinder. The components were purchased from DA. I used an extra piece of heat shrink because the metal jacket was frayed and did not want to shorten the cable since it was in otherwise good condition.
2 sets of carburetor rebuild kits were acquired from DA .
Work has begun this morning on rebuilding the original carburetor.

I will post pop off pressures and other data shortly.

Again, the goal is to achieve 6200+ Rpm with the 30x10 prop and 5800+ rpm with a 32x10. To date I have not been able to go over 5650 RPM. Tha last 10 % in RPM gives quite a bit of HP.

Right now the only reason the engine is not performing is due to fuel mix.

One of the best explanations of pop off pressure I have seen.

http://inventions.aerocorsair.com/id38.htm

This next thread shows how a carburetor works.

http://inventions.aerocorsair.com/id142.htm

I was good to meet you Sunday, thanks for the cigar! I'm glad you were able to see Mark's Dalton with a DA-150 and my DA-120 powered Extra fly! As hot as it was, they both got a good workout, and I flew more IMAC style as opposed to hovering all day in those temps.

Originally Posted by ghoffman

I was good to meet you Sunday, thanks for the cigar! I'm glad you were able to see Mark's Dalton with a DA-150 and my DA-120 powered Extra fly! As hot as it was, they both got a good workout, and I flew more IMAC style as opposed to hovering all day in those temps.

It was a good day , wasn't it?

I will have a video comparing the pop off pressure of several WB27 carburetors this evening.