J

jim

Well Known Member
Hi group,

I am flying an RV-6 with Lyc 0320 160 hp and sensenich fp prop. The performance has been good. I have been thinking about possibly changing props. Why? On long cross country with full load, as fuel burns off cg shifts aft, don't like the handling. Only do occassional long xc tho. I do land at a field which is only 2200 ft with obstructions at one end fairly often (every 2 to 3 weeks in the summer). Home strip is 5,000 ft so it's not a problem. Float at the short strip can be a problem. I am not convinced I need to change props and am just considering options.

I like what I have seen posted about catto 3 blades, but realize that I would be going the wrong way from a W&B and cg standpoint,even with a harmonic dampener, so that's probably out.

If I were to go to the Hartzell CS prop that would be the right direction for weight considerations. I used to have a Cessna 180 and liked the CS prop.
My concern is how much of a hassle is it to convert to constant speed. The engine is ok for cs, how much problem with cowling changes on the 6 would be encountered.

I have not concluded if the $ would be worth it, just considering it.

Is there a lot of change needed to the cowl?

Thanks,

Jim Tambs
RV-6 purchased
building an 8
 
Jim,

If you are satisfied with the performance of the Sens and simply need more forward cg why not consider a weighted prop extension and crush plate from a company like Sabre Manufacturing or the flywheel wt system marketed by Landowl (sp?)??? Sure would be cheaper and easier than switching to a cs prop!!

Cheers,

db
 
I was also referencing Saber Manufacturing in Granbury, Texas. Same company mentioned by Darrell. I have one of their aluminum 4" extensions on my James cowl/RV9a----it is a work of art--almost too pretty to put on an airplane!! For a stock cowl RV you will most probably need the shorter version. Get out your wt and bal info and calculate how much additional wt you would like to have on the nose to get your cg where you want it and Saber can make one up for you!!

Cheers,

db
 
db1yg said:
I was also referencing Saber Manufacturing in Granbury, Texas. Same company mentioned by Darrell. I have one of their aluminum 4" extensions on my James cowl/RV9a----it is a work of art--almost too pretty to put on an airplane!!
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Weird...it's the same people, but different states, hmmm...search the bottom of Performance Props page & you'll find the www.sabermfg.com link. Wherever they are, get it from them. Not sure if Judy is still making them or if she sold off the business though. I had one of Clark's props & Judy's prop extensions on a previous plane - like db said, almost too nice to hang on a plane.
 
Switching to a C/S prop

I just finished changing my 8 from fixed to C/S prop. Lot's of work but worth every minute of it.
I had to install a new throttle quadrant, run prop cable, reroute manual trim cable, install governor and pad with the shaft and gear. You have to make sure you have the allen plug in the center of the crank and that there has been no hole drilled in it. You have to have the plug in the crank to pressurize the prop with engine oil.
As for the clearance of the spinner and cowling, I measured mine from the front of the flywheel to the end of the cowl lip and sent that measurement to Whirlwind (I bought a WW200RV) and Greg Anderson specially made me a spinner backing plate to give me the clearance I needed. It fit perfectly.
It was a big job but to me absolutely worth it.
I also had to reweigh the airplane and figure the new CG. This is considered a major mod to the airplane.
I can't begin to describe the difference it makes in the airplane.
I say go for it and put on a C/S...
 
If you decide to go the CS route, I have all the "kit" needed to make the conversion (prop, governor, cables, etc.) and plan to sell soon as it will not work with the crank we have.

James
 
for metal sensenich

db1yg said:
Jim,

If you are satisfied with the performance of the Sens and simply need more forward cg why not consider a weighted prop extension and crush plate from a company like Sabre Manufacturing or the flywheel wt system marketed by Landowl (sp?)??? Sure would be cheaper and easier than switching to a cs prop!!

Cheers,

db
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Dave,

I wasn't aware you have this option with the metal sensenich fp prop. Wouldn't a weighted prop extension involve redoing the cowl? Crush plate is only for wood props right? Not familiar with the flywheel weight system, I'll have to check in to that.

Empty weight as is, is around 1068 lb, and for most of my flying cg is not an issue. When the wife and I flew to LOE in '05 is when I "learned about" the significance of aft cg. Realistically, 99% of my flying is solo, even two up flying is not issue, until you load up the baggage compartment.

When I visit my dad every other week I'll fly into the shorter strip and that's the biggest issue, the breaking effect of the cs set up would be nice on those flights, and the extra weight of the cs would be a "bonus". I was just considering options but really don't want to get in to fiberglass mods on the cowl.

Thanks for the input,
Jim Tambs
dreading the impending winter (Michigan)
 
what is in the "kit"

jclark said:
If you decide to go the CS route, I have all the "kit" needed to make the conversion (prop, governor, cables, etc.) and plan to sell soon as it will not work with the crank we have.

James
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James,

Thanks for the response. What components will you be selling and have you figured out a price? Is everything new?

Thanks,

Jim Tambs
 
A crush plate can be used on either prop in front of the front spinner bulkhead. They are required for most wood props and will work fine with your Sensenich. It will require a new set of bolts, but Tim will have you covered.
 
Thanks

LifeofReiley said:
A crush plate can be used on either prop in front of the front spinner bulkhead. They are required for most wood props and will work fine with your Sensenich. It will require a new set of bolts, but Tim will have you covered.
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Darrell,

Thanks for the info. Any idea how much weight this adds?

Thanks,

JimTambs
 
Jim,

Saber makes their wt'ed extensions from material that is heavier than their basic aluminum units---the ones I have seen are similar in dimension as standard extensions and require no fg work--this assumes you have an extension now.

Your best bet is to simply call them, tell them what you are interested in, let them know what type extension you have now, and consider the options they provide--my bet is they can provide a product that will fix the problem with minimal work.

If you simply want a cs that is a completely different issue. Your original post sounded as though you liked the Sens but simply needed a more forward cg.

Cheers,

db
 
A Sensenich metal prop is close to 40 lbs. My Catto is 18 lbs. We're starting with the 22 lb because my engine mount puts my engine 2.5" further out than most RV7's. We will weigh the plane when finished, run numbers and fly it if we are in perimeters. Tim stated we will get it just right as he will lathe her down as necessary. Everything should work out fine...:eek:
 
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RV8iator said:
....... You have to make sure you have the allen plug in the center of the crank and that there has been no hole drilled in it.......
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I think the DAMHIK applies here. Wonder if you are familiar with that term! :rolleyes:
 
jim said:
...snip...
When I visit my dad every other week I'll fly into the shorter strip and that's the biggest issue, the breaking effect of the cs set up would be nice on those flights, and the extra weight of the cs would be a "bonus". ...snip...
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I used to fly a Grumman AA5 based on a short strip. I kept the throttle idle setting so low the engine would not run on the ground with the knob all the way out. That gave me the option of having more drag than an idling engine on the approach.

P.S. It is almost impossible to get the prop to quit turning while flying even with no fuel going to the engine. The only way I ever got it to stop was in a deep stall. That resulted in severe shaking. I would never do that again.
 
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