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Cruise

B

Barnstormer

Member
Hello All,
I'm new to the forum and have recently inherited my fathers RV-6/150 Lyc. It still needs the last bit of restriction flown off. Sadly, Dad's gotten too old to fly anymore.

In your experienced opinion which fixed pitch prop/s gives the best cruise speed. I'm willing to give up some climb.

Thanks
Pat
 
Pat,

Welcome to VAF. I'm sure you'll find many answers to your question on this forum, but they will likely not all agree. Comparing speeds of various engine/ prop/ airframe combinations can be something of an apples to oranges comparison, so hard data can be hard to come by.

For starters, tell us more about your configuration and current numbers. What prop do you have now? Are all the pants and fairings installed and alligned? Old or new style wheel pants? What kind of cruise numbers are you getting now, and under what conditions (altitude, temp, engine settings, fuel flow) and we can tell you if you are in the ballpark speed-wise.
 
I called Sensenich wood prop division, told them what performance I wanted and they sent me the prop that exactly matched my requirements.
 
No History

I've not even flown the airplane yet. I know it has wheel pants but I didn't know there was a difference in pants. I know the pants have a vertical seam joining the halves.
I get to spend the next 2 days with the plane and will learn a lot more and possibly get to fly it.
 
Barnstormer said:
I know the pants have a vertical seam joining the halves.
Click to expand...
If this seams goes fore and aft, they would be the old style pants. If the seam goes around the middle from left to right, they would be the new style, affectionately called the "Dolly Parton" wheel pants. Another way to tell is that the old style pants have a "bubble" molded in to cover the brake caliper.
 
Actually there was another two piece main wheel pant that was available during the early and mid 90's that split exactly the same as way the current ones do. The shape fell somewhere between the current ones and teh original one piece.


I regards to fixed pitch prop recommendations...more information is needed on what altitudes you would fly most, when you are wishing to get the good cruise speeds.
A fixed pitch prop that gives the best possible cruise performance at 11,500 will not give you nearly as good performance at 4'500, etc.
 
As has been pointed out, there are many specifics you have to cover to get the prop with what you will consider the highest performance. You might also find that your dream prop might be deficient in some other regard, although that probably wouldn't be too big a deal. Since you already have a flying aircraft, with an acceptable prop, I would suggest you get acquainted with the overall characteristics of the combo you have. You may be very happy (and I would almost bet on it!)

Then, don't overlook some of the other items you will have within your control, should you change props. Noise, weight, ground clearance and vibration all can be part of prop design, too. You are in a better position than most; you can fly without spending money on a prop. Then, if you feel you need something else, chose a good company and have one made for you. I am very happy with my Catto, and Craig Catto can give you what you want--just tell him your requirements. The wait may not be short, but that's what happens when you deal with a popular supplier...

Bob Kelly
 
Congrats on the new plane! Cudos to your dad for building it, flying it, and knowing when to quit.

Craig Catto can help you decided what the best prop would be for your application also. My sugestion however is if the plane is flying fly it and see what it needs. You may be surprised!

http://www.cattoprops.com/
 
Prop

I traveled to my parents and am with the airplane today. It has the Sensenich 70 series prop 79 pitch. Have learned that due to some engine problems during first flights, the prop was repitched to an unknown value.

How should I feel about repitching? If done right, is the prop still safe?

Thanks
Pat
 
rvbuilder2002 said:
Actually there was another two piece main wheel pant that was available during the early and mid 90's that split exactly the same as way the current ones do. The shape fell somewhere between the current ones and the original one piece.
Click to expand...
Oh yeah, I forgot about those.
 
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