Hi Pat,

whether a prop produces "worthwhile" thrust at 0 = forward speed depends on your application.

Remember the Davis DA-9 (??) or so, with Ken Schuggert (?) as the pilot? His prop was = stalled up to about 50 kts(?), idling down the runway (because it would make more = thrust idling than at rpm), until it started to bite.. =

Long take-off roll, but would go like stink once at = speed.

For a CH-801, speed is of no concern, acceleration is everything = - static thrust IS getting interesting here!

Yes, I can agree that if we have a = target number to shoot for and we have a means to measure thrust, it would be meaningful to measure thrust.

But unless you have something you = can do with the results, having the number does precious little.

I assume as a dyno it would be interesting to have a special = static prop to load the engine and eventually it can be used to compare engines/mods/etc. with this one prop as a baseline. Whether this dyno = prop has any aviation use at all doesn't matter, it puts some serious load on the engine. How to calibrate this prop is a different question, but just to = see, whether an engine runs better or worse than before it is good enough.... =

Revmaster has made hundreds of = little 2100cc VW conversions over the past decades. Each one was run on a test = stand with just such a test club.

Specifically this one right = here:

www.ContactM= agazine.com/Issue80/TestClub.jpg

When they bolt it to a new engine, = they should see a certain RPM or there’s a = problem.

""""snip"

Ok... I've seen countless little red biplanes hang = from their prop at airshows; certainly the prop is "stalled", and knowing = that the engine/prop combination can produce thrust to counter the gross = weight in order to allow the plane to hover is useful information to this small = group of pilots. But how many of us really need that info? =

"""snip"

If that prop is stalled the bird comes down!! Just because the = plane has zero speed, does not mean the prop is = stalled.

Ok, now you are splitting hairs. = <= span style=3D'mso-char-type:symbol;mso-symbol-font-family:Wingdings'>J<= /span> You know what I meant. In fact, you used the same term in = the second line in the quoted message above to describe a prop that is in = fact not stalled. But if you are going to split hairs, some part of every prop is stalled at almost every airspeed, except an Elippse, and that’s = only when the plane is going the designed speed at the designed = RPM.

Pat <= /p>