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Prop delamination, RV-6 stuck on cross country, HELP!

kismet

Member
https://www.flickr.com/photos/brooksmershon/albums/72157676935626358

Felix (custom) wood prop that is meticulously inspected got me from Denver to Doylstown, PA. Upon inspecting the prop today a few days before heading home, I realised there are several points of what appear to be delamination that may have occurred from the humidity and temperature changes after arriving.

I look at the prop carefully, so the changes must have occurred after or during the 8 hours of flying from Denver.

I'm looking for folks with a prop I can buy to get back home.

It's a o-320 making ~165hp on what is currently a 198mph cruise RV-6.

Again, currently stuck at Doylestown Pennsylvania and looking for a safe way to ferry the plane back to Denver.

Thanks all!
 
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Felix (custom) wood prop that is meticulously inspected got me from Denver to Doylstown, PA. Upon inspecting the prop today a few days before heading home, I realised there are several points of what appear to be delamination that may have occurred from the humidity and temperature changes after arriving.

I look at the prop carefully, so the changes must have occurred after or during the 8 hours of flying from Denver.

I'm looking for folks with a prop I can buy to get back home.

It's a o-320 making ~165hp on what is currently a 198mph cruise RV-6.

Again, currently stuck at Doylestown Pennsylvania and looking for a safe way to ferry the plane back to Denver.

Thanks all!


Hi Brooks

Pray for a prop to come in your possession quickly. People will need to know what size bolts you need the prop to be for. On a o320 it?s either 3/8? or 7/16? bolts.

Bill
 
Don't know if you want to attempt a repair, but I've had a cracked (not delaminated) prop repaired by Amar-Demuth and they used ...super glue.
 
Without the same prop model and part number, will this require a return to Phase I and a 5 hour fly off?
 
If nobody on the list has a suitable prop, you're only 85 miles from the SENSENICH factory and their East Coast Propeller distributor and repair facility.

Cheers, David
RV-6A KBTF
 
Without the same prop model and part number, will this require a return to Phase I and a 5 hour fly off?

You'll probably get different answers depending on who you ask, but FAA sources I've seen quoted say that it isn't a major change unless you change *type* (fp to c/s).
 
If nobody on the list has a suitable prop, you're only 85 miles from the SENSENICH factory and their East Coast Propeller distributor and repair facility.

Cheers, David
RV-6A KBTF

Sensenich is absolutely looking like a best option at this point. Any recommendations before I talk to them? I'm favoring a fixed pitch metal prop for ruggedness and stability; I'm already aft-biased on CG and wouldn't mind pitch stability and higher gyroscopic forces, since I'm not aiming to perform (more) acro in it.

Again: looking at pitching for cruise on a 320 making 160++ hp due to Vetterman exhaust and cams that open valves a bit longer. Good compressions. I cruise at 198mph currently at 8,000 ft.
 
You will need a 70CM6S16-0. 80 inch pitch, from Vans catalog. Ask Sensenich if they have any seconds or returns..... These are great deals. The spinner will need to come from Vans....
 
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You will need a 70CM6S16-0. 80 inch pitch, from Vans catalog. Ask Sensenich if they have any seconds or returns..... These are great deals. The spinner will need to come from Vans....

Thanks! I settled on a similar prop reading the docs, but saw differences in the spacer dimensions. 2 1/4" vs 4" (the 9 vs 16 designation on the trailing end of the number; the number of 1/4" increments on the spacer length).

Silly question, but should I assume that the spacer is irrelevant here on a built plane and the only variable to worry about is the 3/8 bolt size and possibly bolt length? The spinner back plate is currently what crushes against my wood prop. Would the metal FP prop from Sensinich and a suitable (aluminum) spinner assure everything just fits?

I'm assuming 3/8" bolts in a 6 pattern is universal in terms of drilled placement when we are talking about a lycoming engine that has an adapter on it.
 
If absolutely necessary you can buy a set of Lycoming 7/16" prob bushings and change them. No drilling needed. Unfortunately I don't have the part numbers, sorry.

I see you're local. There's an area RV group that's reasonably active on line. Contact Wirejock, here on VAF, to get in.

Good luck!
Dave
 
Thanks Dave,

On a built plane I'm assuming the length of the extension is irrelevant. I'm driving out to the plane to take the prop off, dimension everything, and photograph everything. But is it correct that the extension length is irrelevant and whatever extension comes with the sensenich prop is just a paperweight for me in my situation?

Currently interested in 70CM6S16-0. 80 inch pitch but my unknowns are bolt length required and it would seem whatever the manufacturer includes should account for the spinner backplate and extension. Just trying to get all my ducks in a row before ordering.

This is a fix being done "away from home."
 
mention of not fitting my 3/8" bolt holes on the current prop flange that is mounted. Only 7/16 and 1/2 supported.

Also this from their website: We have a composite spinners available for this propeller to match up to the RV cowling. This propeller mounts with 7/16″ & 1/2 bolts only! Please specify bolt size when ordering. If your adapter or spacer has 3/8″ bolts on the prop side contact us first before purchasing.

Cheers, David
 
The Sensenich F/P metal prop uses a totally different extension than a wood prop. Early RV-6 used a 4" extension for F/P and a 2 1/4" extension for C/S.
Later airplanes all used the 2 1/4" extension so that Van would not have to produce 2 cowlings. You need to know exactly what you have before ordering a new prop. If you are going from a wood prop to a F/P metal prop, you must know which cowling you have and must order the extension and bolts with the prop.
 
I may be unclear on what you have, but the size of the extension is very relevant on my plane. The cowl is fit using the extension. Better take some pictures and measure the extension when you go to get a new prop. I would take everything that is bolted to the engine flange. Maybe the prop company will come see you? For what a prop costs, it would be worth it for them. Good luck.
 
Measurements and pictures tomorrow

Edit: I see rockwoodrv9's point: I'll just unbolt the extension from the engine and take everything with me to sensenich if/when it comes time to plop down $$$$ for a prop. That should avoid anything being wrong.

re: extension length, I was just under the impression that the extension mattered for cowl fit while the plane is being built, but the spinner backplate wouldn't change distance from the cowling with a change in prop (and spinner). Since I'm changing fixed pitch to fixed pitch, I figured perhaps bolt length might need to change, but that the cowl clearance wouldn't change much.

I clearly won't have a prop in my hands for a few days, but to avoid a mistake, I'm taking the prop off and getting lots of pictures in hand tomorrow so you guys and Sensenich can help me be absolutely certain.

Appreciate all the help. I'm just a 25-year-old dude trying my best to learn quickly. Although it's bad timing to need a new prop over the holidays over half of the country away from home, at least I didn't shed the prop on my way back.

I'm hoping sensenich techs can help me on the phone to be absolutely certain.

See the pics: https://www.flickr.com/photos/brooksmershon/albums/72157676935626358
 
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FOr best price, you'll want to order it through Van's. Ask them to arrange a factory pick up instead of the usual drop ship.

Larry
 
Extremely important question

You mentioned a fairly high cruise speed; what rpm doyou use for cruise? I'll bet you're using close to 2700 rpm at altitude. *Be aware*: Ain't gonna happen with the Sensenich metal prop for a Lyc 320. RPM limit is 2600.

Charlie
 
updated photos

see https://www.flickr.com/photos/brooksmershon/albums/72157676935626358

I have the prop off, pursuing local sources. I can't seem to find Sensenich's online wood props that might be appropriate for my RV-6; I only see suitable metal ones at over $5,000!

It seems I have a 3/8" bolt, 4" long prop extension. Tell me if I'm being wrong based on the photos. The mating hub and the "bolts sticking into the prop are some standard size, I would hope, at least for wood props. Perhaps the metal extender needs to be used to replace my 4" extender.
 
http://www.sensenich.com/shop/aircraft/w68t6em/
But, you may find that there are long lead times for any new wood prop. Sensenich might have their composite props in stock, but they are big money.

Someone has a used Sterba listed in the classified section, if you want to just get the plane home.

Hub thickness determines bolt length. Assuming correct hub thickness, 7/16" holes can be sleeved to 3/8 for your bolts.

Charlie
 
That's shoddy safety wiring I see on the prop extension. You'll want someone knowledgable and qualified to retorque and properly safety those bolts.

Who ever completed that front end inspection wasn't doing you any favors.
 
Tell me if I'm being wrong based on the photos.
Looking at the photos, the Great American prop that I have been flying behind for years looks a lot worse than yours. But if you're not comfortable flying behind it, then do whatever you think is right.
 
Looking at the photos, the Great American prop that I have been flying behind for years looks a lot worse than yours. But if you're not comfortable flying behind it, then do whatever you think is right.

I certainly wouldn’t fly with the OPs prop. Maybe you should re-evaluate your standards??
I’ve seen wood props come apart— it’s not a good ending!
 
I certainly wouldn?t fly with the OPs prop. Maybe you should re-evaluate your standards??
I?ve seen wood props come apart? it?s not a good ending!

I have to agree. A prop is not a place to take shortcuts. It is a critical piece of your airplane. PLEASE do not fly behind a wood prop that has obvious delamination. Think about how fast that prop is going. I too have seen wood props come apart. Is is NOT a pretty sight. I have seen shattered props shake the engine right off of it's mounts.
 
First, thanks all for the comments and advice.

I certainly wouldn’t fly with the OPs prop. Maybe you should re-evaluate your standards??
I’ve seen wood props come apart— it’s not a good ending!

Believe me, I didn't like the additional drama added to my trip east. Here's a video of me being stranded in Kansas due to an electrical problem (broken wire, unrelated!) that occurred just a few days ago.

https://youtu.be/qal7ZjhiYs0


Now, the prop is off and it seems tomorrow I'll get a wood prop off an RV4 (150hp, so propossibly more of a standard prop for my 160 hp RV6). I'll hopefully get a spinner too, but at the least with safety wiring the extension and flying without a spinner I can safely get back to Longmont, Colorado.

Immediately after I am interested in getting the real deal mounted on the plane, taking care of my aft C.G. bias in the process.

I see a few options:

(1) Metal FP sensenich prop (anyone want to talk me out of it?) I have a VFR only plane that avoids rain. $5,300 is a lot of money for a certified prop on my RV6.

(2) Catto prop, hopefully I can wait it out with my $500 wood prop I'm buying tomorrow. Add a saber crush plate with some mass on the front end to move CG forward.

(3) Sensenich Ground Adjustable prop with perhaps a heavier extension from Saber.

I feel silly for not taking off the extension on the plane and just trusting the mechanic's eye that the bolts are 3/8" on BOTH ends of the extension. I know the prop bolts are 3/8" and assume I don't have 7/16" on the engine facing side of the 4" extender that is currently on the aircraft.
 
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My vote, if you can wait it out, is 100% for the Catto. I've flown behind a lot of different F/P props in my 51 years of flying and I've never found anything else close to the performance, smoothness, and quietness of the 3-Blade Catto. Oh, and as I have stated somewhere before, it looks Sexy as H. E. double hockey sticks.

And BTW, it will fit your current extension.
 
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To add to Mel?s comments...I just got a quote from Cato and their pricing is competitive for the 2 blade prop. The 3 blade is more. If you don?t get the nickel leading edges you can save more, but I won?t be doing that.
 
The prop is in very bad shape glad that you didn't try to fly it or fix either one. The person who said use super glue and it would fix the problem is nuts. The prop is junk split clear down to hub no fixing that one as its swelled due to moisture. Fix it by using the thing for hangar decorations.
 
If I was replacing the prop, I would go with 7/16 prop bolts versus 3/8. Also if your4? extension is only 6? diameter, be a good idea to replace with 4 in extension that is 7 in diameter.
 
Got a prop

https://www.flickr.com/photos/brooksmershon/albums/72157676935626358

See photos

Pacesetter 200 it seems. Slightly under pitched based on RV4 150hp that it came off of, but I'll mount tomorrow and fly soon to test it out.

I plan to upgrade crush plate and extension to larger surface area and sort it all out by talking to Craig Catto.

At this point, it's either 2 or 3 blade Catto with nickel edges being ordered once the plane is back in Denver.

Thanks all!
 
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I plan to upgrade crush plate and extension to larger surface area and sort it all out by talking to Craig Catto.
Craig will want you to order a 7" dia extension with 7/16" prop bolts from www.sabermfg.com.

If you order the three-blade, it will be smoother and look sexy, but your glide ratio will suffer if you care about that.
 
Looking at the photos, the Great American prop that I have been flying behind for years looks a lot worse than yours. But if you're not comfortable flying behind it, then do whatever you think is right.

I would consider replacing the prop. If it failed in flight the outcome is likely to be fatal.
 
I would consider replacing the prop. If it failed in flight the outcome is likely to be fatal.
Oh, would you "safer than thou" guys just stop it? The ugly parts of my Great American prop are just cosmetic, not structural and the Great American props used micro-laminations rather then just three or four as in the OPs case - a much more sound way of building a prop. I've flown across the Country with this prop and even (accidentally) had it up to 3,000 RPM not long ago. If the prop were going to fail, it would have done so then. My engine didn't fly apart either. Not all of us can afford to shell out $2,500 for a new prop every time we see a minor, cosmetic defect.
 
Oh, would you "safer than thou" guys just stop it? The ugly parts of my Great American prop are just cosmetic, not structural and the Great American props used micro-laminations rather then just three or four as in the OPs case - a much more sound way of building a prop. I've flown across the Country with this prop and even (accidentally) had it up to 3,000 RPM not long ago. If the prop were going to fail, it would have done so then. My engine didn't fly apart either. Not all of us can afford to shell out $2,500 for a new prop every time we see a minor, cosmetic defect.

I am going by your statement that your prop is the worse than the OP?s which is not just cosmetic.
 
Alright boys and girls,

Flew the pacesetter without a spinner today (no backplate). Honestly, I think it's almost the same speed with the little "test pilot" wind triangle I did. Regardless, climbs amazingly and ran smooth enough by just leaving my existing dynamic balancing washers where they were.

Not bad.

See the pictures: https://www.flickr.com/photos/brooksmershon/46479054151/in/album-72157676935626358/

Watch the CHT's in case the absence of a spinner disrupts airflow into the cowl.
 
Awesome. You did good.

I agree; Pacesetter made really good props. And if performance is similar to your previous prop, that's a real bonus; it's rare to get a good match when you're forced by circumstance to take whatever is available.

Charlie
 
I wonder why so many propeller manufacturers have gone out of business. Great American, Aymar-Demuth, Pacesetter...
 
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