Cowlings, propellers, extensions etc

[Andy_RR]

I have been recommended by a fellow Aussie RV builder to consider ordering the finishing kit as part of my whole RV-8 order to save on shipping. Now ignoring the merits of this suggestion, I have a few questions regarding propellors, cowlings and extensions.

I would like to go for the James Cowl which apparently requires a 4" extension or an extended hub on an RV-8. What does this represent in terms of hub to blade centre offset - as appears to be measured by MT in their drawings? (e.g. http://www.mt-propeller.com/pdf/datsheet/mtv-12.pdf) What hub length would need to be ordered?

Also, someone has suggested that extended hubs are not available in aerobatic/counterweighted form. I want to confirm this with potential propellor suppliers, but the question above needs to be answered first, I think.

Any info or leads would be much appreciated.

Regards,

Andrew

[frankh]

I suggest you check the archives,...There is almost more heated debate about this issue than primer!

But the short answer is the james colw is designed for an extended hub hartzell C/S prop.

If you buy the compact hub Hartzell prop you will need a 2 and 5/8ths inch extension...(I used a 2 1/4") .

The above assumes the old style "Long" cowl. James now has a short cowl that avoids the prop extension.

Frank 7a and yes I fly aerobatics!

[Andy_RR]

Frank,

Thanks for your help. I'm not trying to start a war here. I did actually do an archive search but not a lot seemed to come up. Your post triggered a few more search terms to try and I begin to see why you think I'm war mongering!

I did discover the ShowPlanes cowl in my new search, so thanks!

You mention that the SJ cowl is for an extended hub hartzell, but do you (or does anyone) know what the flange to blade dimension is with these? (dimension 'X' in the MT drawings)

Regards,

Andrew

PS: I'm going RV-8, so unless I'm mistaken, I believe there are no short-cowl options for this

[rv8180]

Originally Posted by Andy_RR

Frank,



.............
PS: I'm going RV-8, so unless I'm mistaken, I believe there are no short-cowl options for this

Andrew,

I doubled checked some months ago (right after they re-designed their tooling) for a short cowl for the RV8 and they did not have one available then.

[RVjim]

When you order the MT Propeller, you will just need to provide the spinner diameter and cowl spacing. MT Propeller determines the correct hub length and spinner assembly to meet your requirements.

The counterweighted blades are available regardless of hub length for the MT Propeller. There are no aerobatic restrictions on the MT Propeller with the Sam James cowl.

Regards,
Jim Ayers
Less drag Products, Inc. - A MT Propeller distributor

[Andy_RR]

Great stuff! This is what I need to know. Thanks Jim!