[Guest]

Originally Posted by grizak

In our experience, a XOAR 22x8 works well as a break in prop or a regular flight prop with a DLE55 (or an MT57).

Other brands of 22x8 props may not load the engine as much and may not be as suitable. It all depends on the particular brand. (Some brands load the engine less, some load the engine more - but in general Xoar props tend to load an engine more than the average)

Many of our customers have gone to a Xoar 23x8 for more pull, and many have tried a 22x10 for more speed. It all depends on the performance you are looking for.

Grizak

Exactly what he said...lol

I have a 22 x 10 for IMAC stuff and the 23 x 8 for 3D.

[volksman]

hmmm awful funny one of them 22x8 zoars on a downline, unloaded on my mt 57 poped the gasket out from the case halves and shreaded the reeds. i wondered why they would even suggest running it ray at paragon said their wasnt enough load from a 22x8. this is not my first gas engine either. quite evident to me what happened. over pressurization in the base from an over speed

[RAMJET]

the idea of break in is to allow the engine to seat the ring & bearings without excessive load ,of course you could over rev any motor on it's break in prop and cause damage ( care must be used when breaking in a motor)throttle management. the problem with break in with bigger props is the greater pressure on the unseated ring forces hot gasses past the ring ,this is also why more oil is recomended during breakin to help seal the ring and keep the heat above the piston while allowing the ring to tranfer that heat to the cylinder wall. blow by on a new motor can be in the 35% range when pushed hard.only 5%-7% when broken in .

I am all for the use of break in props ,but to each his own .Roger

22x8 sounds good on a 55 but watch that throttle

[mjws]

Originally Posted by volksman

hmmm awful funny one of them 22x8 zoars on a downline, unloaded on my mt 57 poped the gasket out from the case halves and shreaded the reeds. i wondered why they would even suggest running it ray at paragon said their wasnt enough load from a 22x8. this is not my first gas engine either. quite evident to me what happened. over pressurization in the base from an over speed

The MT doesn't have to over rev to spit the case gasket. Lots has been written about them elsewhere.

22x8 just isn't much prop for a dle 55. I have a few of them, some have been broken in on a lighter load. Others have just been flogged from day one, there is absolutely no way to tell the difference between the two. Done the dino -> synthetic thing. The reality is the guys that say fire it up with the oil you intend to run, get a few easy heat cycles on it in the air, enjoy; are on to something.

Mike

[Bdegan]

Well I was mistaken. They had a 23x8 in stock not the 22.
So the 23 went straight on it.
I mounted the motor to a test/ breakin stand and brought it to the field.
I know, why do that ???? Well........I wanted to play with the motor first before mounting it in the plane. Set the needles etc.
The engine fired after a dozen flips. needle tweeks were a bare minimum.

There is no comparing this engine and the DL50. I had one of those last summer. This engine ran so much better. Idle, full throttle, transitions. Alll were smooth and flawless.

Its all mounted in the plane now and will be out at the field first thing in the morning. Providing it isn't raining.

Grizak,
yeah....nice prop
I will wait until I get a better landing gear first



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[volksman]

again not going to flog an old horse here but the above explanation makes a bit of sense, at least presented in a professional manner. with out heat the ring will not expand, closing the end gap, forcing the ring to the wall. the high points left from the final hone of the cylinder plating and square edge of the ring must run together once they are run together its sealed and broken in a simple explination. heat cycles etc are a crock. the engine components are treated when new, if any. the rings are treated to give them elasticity or spring tension and hardness. the designer determines the longevity with the alloy choices. good is not cheap.
thermal expansion is the reason the engines run well or not. a dl will out pull a da im told but the da needs a new bunch of parts much quicker. cheap is that. the old saw engines are still running because they had decent designs, with good materials. oil lubricates and disipates heat. they are not all equal. good example my old saw the chain oil doesnt last a tank of fuel. the hot chain and bar basically stuck together from heat the engine wont turn it more than 500 rpm my guess. optimal for oil and when it cools off everything is fine. do this to a new engine it wont be fine. overloading a new engine the clearances havent opened up will result in a seized piston. too cool will result in a worn ring or gouged wall if the parts havent expaned equally. takes a bit of design to make a good engine the alloying is critical