7's CG With Hartzell BA or WW200 RV

Hi everyone, I am building An RV7 and have read a multitude of threads regarding the differences and benefits in these two props, and my question is:

Which prop would be better cg wise if I am using the parallel valve Aerosport IO-375 8.5:1. From what I have read I sense that the 7's tend to be tail heavy, and do not want to limit my baggage capacity, that's one reason I wanted the 7.

Is the WW too light?

I like the speed from these two props, BUT -

I am still unsure if I should not just go with a straight aerobatic prop with counter weights. I have a lot of aerobatic experience in Pitts and Extras, and do plan on light to medium aerobatics - no snaps or tumbles, but plenty of hammers and some inverted and negative g like a pushover humpty or such. Even with an inverted oil system, there may be moments of very low oil pressure. Has anyone experienced momentary high RPM's on hammers or holding an inverted line for a few seconds or pushover humpty?

All advice is appreciated!

Thanks, Damon

I did some more research

and based on that it looks like the MTV-15-B-C/C-183-50 might be what I am looking for. Price is right for an aerobatic prop, for sure.

Does anyone have any cruise speed info for this prop? How does it compare for W & B?

I am still interested in my original question about CG with the WW and Hartzell, sorry for my own thread drift!

I really like my WW prop but I did not pay enough attention to this issue when I sold my new Hartzell for a WW. I am limited to about 50lbs of baggage when light on fuel. I have moved everything I can forward but I will need to add unwanted weight up front to make much difference.

IO-360 M1B (parallel valve) and Hartzell CS. No cg problems with 100 lbs of bagagge.

Martin Sutter
Building and flying RV's since 1988
EAA Technical Councelor

Thanks!

Thanks for responding. Looks like the Hartzell would be a better choice if I go that route. From others' experience read on other threads it may be there have been no problems if the inverted system is set up correctly for hammers and limited negative g flight, but I will talk to Hartzell and Aerosport more about this.

I still need to find the weights of the MT and the Hartzell to compare for W&B now.

thanks again!

my experience

ditto John's experience (and I suspect, many others).

My RV-6, IO 360 parellel valve with RV 200 at 1096# empty could certainly use some more weight forward. I have looked at a number of things but nothing would be as effective as the 20+ pounds heavier Hartzell on the nose.

Flys great (light and responsive) but gets nose sensitive with a pax and low fuel on landing. Is pretty much neutrally stable in flight at cruise. Not unstable by any means, but neutral.

Aft baggage is limited 75# or below in most w&b conditions with a pax.

I think the Hartzell is a better CG choice although the RV 200 works too.

Big engine... light prop...

I vote for a big engine and a light prop No CG issues for any load condition.

Harmonic Balancer?

For those with the WW and/or anyone who knows, would it be possible to use something like a Landoll Harmonic Balancer to add some weight to the nose and still use C/S?

Glenn Wilkinson

I used a Saber prop extension and an extended James Cowl. This puts my WW200 prop out another 2.25". Empty weight 1095#. Only time I have a aft C.G issue is minimum fuel and 2 people with 100# bags.