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gonzaviador 05-10-2017 03:53 PM

RV-7 and Cato Prop weight advice.
Hi Group. I want to ask some questions related to the Catto prop use in a RV-7 and the effect that it has on the CG, and how to address it. I know that a lot has been written about this issue, so is not my intention to start a new tread on it. My engine will be the Aerosport Power IO-375.

My first choice would be the Aluminum Hartzell, but the only issue that I have with it is, since I'm in Chile, I don't have an authorized Hartzell repair facility here (although there are many maintenance facilities that can do the job), and want to avoid the regular maintenance schedule and costs.

I've read that many of the ones that have used a lightweight prop had cg issues, but other seems to be flying fine with no issues, so I'm a little puzzled.

In short, my questions are:

- There is a way to use a Catto Prop in a RV-7 and don't have CG issues? How? (heavy crush plate, extension, and so on... where do I purchase such items?)
- The use of the Catto will require some kind of mod to the cowls or other part of the airframe?
- Does the prop has a regular inspection schedule? can be performed by yourself or do you need a maintenance facility to do it?
- If little damage occurs (nicks), there are guidelines to verify yourself if it still airworthy? Can this little damages be repaired by yourself?

Thanks a lot for your advice.

swisseagle 05-11-2017 10:05 AM

Heavy crush plate ...

My buddy is running a Catto prop with a 14lbs crush plate to keep things aligned. Nicole at Catto organized it from Sabre Manufacturing.

Works fine!

climberrn 05-11-2017 01:40 PM

Not sure how far along your build you are, but I'd tell vans you have a 0-320 and get the motor mount for that. From what I understand it's an inch longer. Better to push the weight out than add extra weight. Unless your plane is VERY light...

Let us know what you come up with.

swisseagle 05-11-2017 03:41 PM

The engine mount for 320 is longer ...
It is 2" not one!

Raymo 05-12-2017 09:32 AM

Saber Manufacturing
I wasn't aware of another motor mount option and went with a 20 lb Saber plate on the front. Works great and my CG is well within the aft limit with me at 210, a passenger at 190, full fuel and 50 lbs of baggage. With a lighter or no passenger, I can max out the baggage compartment.

Mine is a -7A, which may differ a little.

Vansrv7arob 05-13-2017 11:44 AM

I used the 320 mount, need to order 360 cowels unfortunately you'll have to graft about 1.5 - 2 inches on the cowels to give them enough length, Would I do it again? Maybe... Probably, putting a light weight prop on then bolting 20lb of dead weight behind it, kinda an afterthought.... But that way with the spacer does allow you to more easily convert to a metal CS in the future.

zilik 05-13-2017 04:10 PM


Originally Posted by gonzaviador (Post 1172137)
My engine will be the Aerosport Power IO-375.

In my humble opinion is that an IO-375 would only be happy with a constant speed prop.

Why install a performance engine and derate it with a fixed pitch prop?

gonzaviador 05-31-2017 06:19 PM

Thant you very much for your advices. After doing more research locally, I've decided that going with the Hartzell CS will be the simplest way to go.

Thanks again.

drainge 06-04-2017 08:16 AM

I'm flying behind an IO-375 with a catto 3-blade. My plane uses a 14lb crush plate.

WRT "derating" of the engine: the catto is the smoothest prop I've ever used; I'd be tempted to go with it for that reason alone. But beyond that, I just don't see the issues that get talked about endlessly on VAF -- my climb performance is excellent, even at the high elevation of my home field; cruise is very comfortable at 165kts and 60% power; and I have no issues slowing down.

I'm sure I could eek out a bit more with a CS prop, and I do wish I could take advantage of the 3 blade without the heavier crush plate, but as far as the 375/prop combination goes I'm very pleased.

Did I mention the looks? It looks amazing -- and we all know that makes it faster.

mmcelrea 06-11-2017 07:49 PM

Hi Dan.
What is the takeoff distance and landing distance with the catto on the aerosport? Thinking the same combo myself but will be operating of a short grassstrip, 450yards.

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