Hi, I am going to be breaking in a couple of new engines and I do not really want to do it on the airframe. Does anyone have any design suggestions for building an engine test stand for a 150cc size engine??? Thanks

Larry

Just put the engine on the airplane and fly it. It takes GALLONS and GALLONS and GALLONS and GALLONS and GALLONS of fuel to break in a 150cc engine. Your going to be spending a lot of $$ on gas just to sit there and watch it run tank after tank of fuel to break it in.

I dont think breaking in an engine on a stand is the way to go but, I generally test fire them, put a little time on them, enough to bring it up to temp and then fly it. The stand shown works better than anything else I have seen. Nothing has moved it yet and its had a dozen or so 150's mounted on it. Make something that looks like this and you'll be good to go. Its 3/4 plywood, cost me $22.00 to make

Personal opinion, learned through experience, is that you should not attempt to break in a gasser on a test stand. The best method is to put on the plane and fly it new like you plan on flying it forever. It's too easy to run the engine at an rpm that's just high enough for you to fail to note that it's getting hot. At full throttle they get hot very, very fast, but also cool quickly when brought back to idle. Hot for too long equals a dead engine. Running it cool serves no purpose.

Pat

Put in on a test stand or mount in on the plane. Learn the starting procedures that work for you.
THEN GO FLY THE HECK OUT OF IT, SAFELY. Not rocket science.

How true - My big teststand rig is used just for settting up exhaust systems (pipe) or doing reviews on engines
as a break in fixture it is worthless. you can't leave the engine running at a fixed rpm unattended - very unsafe and can easily wreck a new engine.

I tend to agree. I like putting my new motors on a test stand and getting all the settings just right. Also in the fall or spring is a good time, cool air, and all. Also when I do put it in the plane I have a good Idea how it will run, idle, transition and so on.

How come you can take a new chainsaw from the box and immediately load it down to the max cutting down trees for YEARS without breaking it in ? Is the "load" from a wimpy little prop somehow worse than that ? Some of the small Husqvarna saws will happily turn 15,000 unloaded...8000 rpm is screaming ?
The Red Max shop manual says to tach a 62cc saw and make it rich enough to not turn over 13,500 unloaded
We turn our glow GT80s at 11,500 in the air...THAT's screaming...Props are 19x18 carbon...
From the Husky website...The max recommended rpm of the 3.2 chainsaw is 13,000
Wassamatter engine manufacturers, can't your cranks take it ?
Check out www.dolmette.com

Hey Dick, Looks like the same guy that did my concrete did yours too

Well I shake my head and laugh, what gives! It seems to me that these motors for the air are sensitive. They are a special breed, like a fine tuned race horse, and not a Clydesdale by no standard. Brawn is tough, finesse ( my wife helped me on that one) is finely tuned

That concrete is going to stay that way - -

Ditto

Hey Ralph, We have tested our engines and know what they will turn. But show me some one that wants to run that small of a prop to get it.
I raced hydros when I was younger with Mercury 25 hp engines on them with quicksilver lower units. Mercury said max rpms not to exceed 5000. Well it was nothing to get 8k or better with the right prop and that was in the late fifties.
We have recorded 11,400 on our 4.2 on gas,no muffler.And that engine is still running today.
Personally it scares the crap out of me to think of an engine shedding a prop, which I have witnessed. I've seen it happen in the air and on the ground.
Our cranks will handle it. But you had better have a long runway.

11,400 rpm?
Yamaha just released a production motorcycle with a 600cc 4-cylinder (150cc cylinders) engine with a redline of 17,500 rpm.

I guess it depends on how you define "screaming"
The prop size should reflect the type of flying, whether acrobatic or racing...
Running a large prop at low rpm just because the "big boys" do it is keeping an engine from realizing its full potential...If the torque is at 8000, why not use the prop that works there ?
A 24-8 on a 50 is a good example..There would be more thrust from a smaller prop at higher rpm....

Where is the torque peak on a TS52 ? Same as the chainsaw the cylinder came from ?
Or is that proprietary information

troublemaker ---
grumble grumble --
sic em Libby

Hi,
What you think about that:

MMMMM I think is very Rube Goldburg! ...... Kind of like building a better mouse trap.

"troublemaker" coming from someone who runs his small gassers at 10,000 rpm

I just built a test stand. Observed other designs, and tried to incorporate the best features. Made mostly of aluminum except where the engine mounts. Full adjustable. Haven't decided what to mount it to.

Ralph, Hey genius, why ask me? you have all the answers. Or at least you think you do.
Revel in your glory.
You needn't reply I was just passing thru.
If anyone wants any info from us they can contact us direct.

Show off.

Thats pretty cool. Wish I had the tools to make something like that.[8D]

Nice.

I would like to know the current market value of the metal in that mount. I used to work in a machine shop (not a machinist) and metal like that costs a fortune.

You do nice work, my friend.

Look around for a used motorcycle frame. At least you can get some fun out of it while breaking it in...<G>

I get my aluminum at Davis Salvage in Phoenix for about $2.80 a pound, any size or shape...