R&D has its risks and failures and propellers may be one of the most difficult things to develop. Many others have had problems and many are not publicized that I know of.

Hope they keep trying. This is a cool concept.
 
I wonder if this was the prototype Elippse style C/S propeller that Variprop was working with?
 
I like the idea of someone putting out a "new" type of CS prop for the experimental market - especially a lightweight one such as this. I have to admit I'm ignorant of this particular product - what is there in-use track record? The website is a little slim on details...
 
Props are deadly serious business and absolutley NO place to take chances. Lots of pilots have died over the years due to prop failures. Stick to what is known, proven and then inspect/maintain your prop properly.

Let some other fool test new prop designs.

Bob
 
I agree with Bob. I thought that losing a blade may result in the quick loss of the engine. If that happens you are dead.

People need to be cautious about being early adopters of new components. Just because your plane is experimental and you have wide latitude does not make it safe.
 
Ron Lee said:
I agree with Bob. I thought that losing a blade may result in the quick loss of the engine. If that happens you are dead.

People need to be cautious about being early adopters of new components. Just because your plane is experimental and you have wide latitude does not make it safe.
Click to expand...
Not always.

This is a picture of a good friend's Waco UPF-7 sitting in NY's Staten Island Ferry parking lot:
waco%20upf7.jpg

The prop lost 17" off of one side. The NTSB took what remained of the prop for analysis. Their conclusion, the failure was due to intergranular corrosion, not a nick. In other words, there were no visible signs of an impending failure. In this case the prop was a certified all aluminum Curtis Reed fixed pitch prop.

Note the weeds in the right landing gear, he bounced it off the berm in the background to make the parking lot and then swerved between the light poles missing everything. Eddie is one heck of a good pilot!

His only comment to me after the incident was, "I felt s a small vibration, pulled the throttle back, looked up and realized the engine was gone, it happened that quickly. That Old Bird is a little draggy with the engine hanging down there like that."
 
I know of several incidents where blades have been lost and guys have made it down in one piece but this is not something you want to try for kicks as the results are often fatal, especially in the case of heavy metal props. As I said, several well known names have had failures in the last few years but these incidents tend not to be well publicized. Might be bad for future sales.
 
How many RV builders (or certified for that matter) use a retaining strap to keep the engine attached to the front of the airplane if it should rip out of the engine mount? If you lose the engine off the aircraft, the CG shift is so extreme you're done - no maybes. If you keep it hanging there the airplane is still a controllable glider.
 
One person I know of that comletely lost an engine and survived. He was Dale Crites of Wisconsin Aviation fame. He told me how he immediately put the plane into a dive while he still had substantial forward speed, then flared just before nearing the ground. He admitted it was luck that he did not hit anything hard after the flare, but he did survive the ordeal. Not something he would want to ever try again, though. I don't remember what plane it was. Both the Crites twins (Dale and Dean) are gone now. They lived long and happy lives. Dale built the Curtiss Pusher that hangs in the MKE terminal. Dean built a 1980s Waco. They founded the Waukesha County airport (UES) back in the thirties. Both had pilot licenses signed by Orville Wright.

Roberta
 
F-1 guys do..

Before I raced my Cassutt in 1974, the PRPA (Prof. race pilots assn) required a retaining cable from the top left motor mount over the rear cylinder and down, under the engine and back up between the other two cylinders and attached at the other top mount. It was a 3/8 cable with double nicopress sleeves on each end.

One racer, Jim Wilson was ferrying his Cassutt home from Indiana to Texas and slung half a blade off his metal race prop and managed to land safely with a dangling engine....saved his bacon from frying. They implored us to ferry only the wooden props.

Another old crop-duster I knew in the 70's had half a blade let go on his Stearman while he was in the field spraying cotton. The airplane did an immediate loop, or 90% of one and went in at a steep angle but he did survive to fly again. They found the missing piece and it had a rock strike some time ago on the rear of the blade and that's exactly where it separated.

Regards,
 
...even further off topic...

airguy said:
If you lose the engine off the aircraft, the CG shift is so extreme you're done - no maybes.
Click to expand...

Roberta is correct. There are instances where successful landings have been made minus an engine.

I am aware of one that occurred in TX (I think) many years ago. Instructor and student in a C-172. Airplane was configured in slow flight with flaps down (probably contributed to successful landing because of the resulting nose down pitching moment) and the student had a hood on.
They had a midair with a tweety (T37) which took the engine off the front of the 172. The instructor directed the student to help him push hard on the yolk and he made a successful forced landing in a field. Only after they were down did the student remove the hood and see what had happened. I don't remember what the outcome was with the T37.

Moral of the story...never give up...fly the airplane. (as the RV pilot did in this thread so I guess that makes it sort of on topic)
 
More "Further Off Topic"

A Vari-Eze lost it's engine during a high speed pass and subsequently landed OK. If I remember correctly the cowl came off and took the prop with it. The impact/imbalance tore out the engine. The tower reported to the pilot that they saw something fall to the ground. This later turned out to be the engine. The pilot needed more back stick than usual but landed OK. He obviously knew something was wrong, but being a pusher he had no idea he had lost the engine until he got out and had a look :eek:

Fin
9A Flying
 
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I know at least two guys who threw a blade out of a GSC ground-adjustable after the wood sheared along the grain. Really dumb design.

My buddy Ron Collins was just about level at the end of a loop in an Avid Acrobat when he heard a loud bang and the nose of the cowl exploded. A forced landing in a field came shortly after. When he walked around to the front, he found the entire Rotax gearbox missing, propeller and all.

When I arrived with the rescue trailer, he was convinced the gearbox had somehow seized or locked, tearing the box off the engine due to propeller inertia. The engine was hanging by one remaining unbroken mount tube. Both the carbs and the exhaust Y-manifold had been thrown off the engine. In the case of the exhaust, that meant it had shaken hard enough to break six 8mm screws. Given the evidence, I told him he had lost a blade.

It took two evenings of air-searching with my L-4, but Ron finally spotted the gearbox with one blade attached, in the edge of a treeline near where he thought he was at the time. The empty socket contained the epoxy cup and sheared wood fiber from the missing blade.

Looked like this (photo from a different airplane. The feeler gauge says the clamping is correct per GSC.)


Here's a sectioned GSC blade butt:
 
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Pitch Control Systems

My, my, my! How the rumor mill flourishes! It has come to my attention that there have been a lot of rumors and half truths on this website concerning an incident I had with my aircraft on Friday, the 28th of March. We were up testing the performance on our propeller system when I detected a vibration and a loss of power. We were on a course for a left downwind to runway 17 at Aurora, OR airport. I felt that I didn?t have enough altitude to make the field safely and attempted an off field landing. The field I chose was extremely wet with standing water (does it rain in Western Oregon?) and we dug the left landing gear leg in. There were no injuries, only bent landing gear and injury to my pride. There was NO failure of the propeller or system, other than breaking a shaft when we hit the ground. We knocked the tip off of one blade. There were no separations of the blade from the hub. The FAA and NTSB have investigated and we suspect that we had a stuck or broken exhaust valve. When the ground dries out a little and we can get a vehicle to the aircraft, we will retrieve the aircraft tear down the engine. (I had the same thing happen to me several years ago in a Comanche with an 0-360, and it felt the same way.) Because it was a new prop, under the watchful eye of the FAA I did a tear down and found no evidence of any wear or malfunction. Again, there was no failure of the propeller or any of it?s supporting systems.

We have quite a bit of time on this propeller, and the results have far exceeded our expectation. We are dedicated to building a high performance and safe product. I know how the rumor mill works, and there are those out there that are competitors that would like to see us fail. If any of you have any questions, please feel free to contact me directly. Larry Morgan, Pitch Control Systems, 503-804-5508, [email protected].
 
Thanks for the report and glad you are ok. Let us know what you find with the engine as we have an interest on that topic as well.

Keep up the testing. Many of us pilots hope you succeed in bringing a new prop choice into the market and wish you the best.

Well done.:)
 
Vari-Prop

My, my, my! How the rumor mill flourishes! It has come to my attention that there have been a lot of rumors and half truths on this website concerning an incident I had with my aircraft on Friday, the 28th of March. We were up testing the performance on our propeller system when I detected a vibration and a loss of power. We were on a course for a left downwind to runway 17 at Aurora, OR airport. I felt that I didn?t have enough altitude to make the field safely and attempted an off field landing. The field I chose was extremely wet with standing water (does it rain in Western Oregon?) and we dug the left landing gear leg in. There were no injuries, only bent landing gear and injury to my pride. There was NO failure of the propeller or system, other than breaking a shaft when we hit the ground. We knocked the tip off of one blade. There were no separations of the blade from the hub. The FAA and NTSB have investigated and we suspect that we had a stuck or broken exhaust valve. When the ground dries out a little and we can get a vehicle to the aircraft, we will retrieve the aircraft tear down the engine. (I had the same thing happen to me several years ago in a Comanche with an 0-360, and it felt the same way.) Because it was a new prop, under the watchful eye of the FAA I did a tear down and found no evidence of any wear or malfunction. Again, there was no failure of the propeller or any of it?s supporting systems.

We have quite a bit of time on this propeller, and the results have far exceeded our expectation. We are dedicated to building a high performance and safe product. I know how the rumor mill works, and there are those out there that are competitors that would like to see us fail. If any of you have any questions, please feel free to contact me directly. Larry Morgan, Pitch Control Systems, 503-804-5508, [email protected].
 
Kind words

Thanks all for the kind words. THe only thing damaged is my landing gear and pride. See ya @ SnF, space SW4.

FYI - test results.

Fixed pitch SEnsenich: Gross weight with spinner.

ROC: 1325 100 MPH
MPH: 2400 RPM 175MPH

Vari-Prop, Gross weight with out spinner.

ROC: 1925 100 MPH
MPH: 2400 RPM 2600 MP, 183 MPH
 
SB-388C

Larry... you are now a candidate for Lycoming's SB-388C....

http://www.lycoming.com/support/publications/service-bulletins/pdfs/SB388C.pdf

...of course, it's better performed before the stuck/loose valve...:)

Unfortunately, most mechanics don't even know about this SB.

Glad to hear you are OK.

gil A ... found two worn valve guides on my 650 hr. O-360...:(


Pitch Control Systems said:
My, my, my! How the rumor mill flourishes! It has come to my attention that there have been a lot of rumors and half truths on this website concerning an incident I had with my aircraft on Friday, the 28th of March. We were up testing the performance on our propeller system when I detected a vibration and a loss of power. We were on a course for a left downwind to runway 17 at Aurora, OR airport. I felt that I didn?t have enough altitude to make the field safely and attempted an off field landing. The field I chose was extremely wet with standing water (does it rain in Western Oregon?) and we dug the left landing gear leg in. There were no injuries, only bent landing gear and injury to my pride. There was NO failure of the propeller or system, other than breaking a shaft when we hit the ground. We knocked the tip off of one blade. There were no separations of the blade from the hub. The FAA and NTSB have investigated and we suspect that we had a stuck or broken exhaust valve. When the ground dries out a little and we can get a vehicle to the aircraft, we will retrieve the aircraft tear down the engine. (I had the same thing happen to me several years ago in a Comanche with an 0-360, and it felt the same way.) Because it was a new prop, under the watchful eye of the FAA I did a tear down and found no evidence of any wear or malfunction. Again, there was no failure of the propeller or any of it?s supporting systems.

We have quite a bit of time on this propeller, and the results have far exceeded our expectation. We are dedicated to building a high performance and safe product. I know how the rumor mill works, and there are those out there that are competitors that would like to see us fail. If any of you have any questions, please feel free to contact me directly. Larry Morgan, Pitch Control Systems, 503-804-5508, [email protected].
Click to expand...
 
Pitch Control Systems said:
My, my, my! How the rumor mill flourishes! It has come to my attention that there have been a lot of rumors and half truths on this website concerning an incident I had with my aircraft on Friday..... Larry Morgan, Pitch Control Systems, 503-804-5508, [email protected].
Click to expand...

Larry,
In reviewing the thread, I find nothing like a rumor or half truth about you or your business.

The thread starts with a note about an accident report in the FAA database (reproduced in part below....that is you, right?).

Most of the posts relate stories of propeller failures, none of which noted your product.

Perhaps you're being a wee bit over-sensitive?

__________________________________
IDENTIFICATION
Regis#: 65MK Make/Model: RV6 Description: RV-6
Date: 03/28/2008 Time: 2251

LOCATION
City: AURORA State: OR Country: US

DESCRIPTION
PROPELLER FAILED INFLIGHT, AIRCRAFT MADE AN EMERGENCY LANDING IN A FIELD WITH APPROXIMATELY 1 FOOT OF STANDING WATER AND THE GEAR COLLAPSED, AURORA, OR
 
Well Dan, I think "RV-6 Prop Failure - landed" might sound just a little like a rumor or half truth! I'm glad that he cleared that up for us.

Tracy.
 
Just to make sure Dan doesn't get the blame for that statement....all he did was copy the FAA incident report, as published on the FAA website.

It was from the FAA, not Dan. I don't know why they published "propeller failed inflight" if that wasn't the case, but none-the-less it was what they published right/wrong or indifferent... it wasn't made up by any VAF members. Maybe it's inaccurate, and if so then it's good that Mr.Morgan is going to give is the real story.

I'm also glad to get the information from the Horses mouth directly. I'll be watching for an update from Mr.Morgan and appreciate his openess.

Cheers,
Stein

http://www.faa.gov/data_statistics/accident_incident/preliminary_data/events03/media/02_65MK.txt
 
My NTSB data only goes up to 26 March for some reason. I suggest that the owner contact the FAA and/or NTSB to correct any possible errors.
 
PRELIMINARY Reports!

Ron Lee said:
My NTSB data only goes up to 26 March for some reason. I suggest that the owner contact the FAA and/or NTSB to correct any possible errors.
Click to expand...

I read the preliminary reports almost daily, and one thing that is true about "first stories" is that they are almost always wrong in some aspect. This is a one sentence summary, usually a quote from a local sheriff or other nontechnical person.

I for one am a bit embarrassed for VAF that people wanted to take Mr. Morgan to task for this. It was clear that folks wanted to make something of this incident when there wasn't any data - and then when he came on to set the record straight, he was challenged - what a great way to welcome an experimental aviator to our group. That's a good way for folks here to get a reputation that we don't want, and most don't deserve.

Developing propellers is probably one of the most difficult and unforgiving things to do in this business. I expect some failures, and have respect for guys that are willing to do it.

And folks - take those preliminary reports with a grain of salt - they frequently don't even get the type of aircraft right!

Just my opinion...

Paul
 
<<I for one am a bit embarrassed for VAF that people wanted to take Mr. Morgan to task for this.>>

Now wait a second Paul. Yep, FAA prelims are often wrong, but I don't think the thread originator had any intention of rumor-mongering by beginning a thread with a reference to one. He noted a report, nothing more.

Further, no subsequent post knocks Mr Morgan or his product. Most relate stories about prop failures, and just how darn quick they can get you killed. When the engine comes off the mounts, most of the time you die, and there are surely a lot of folks here who don't understand how a blade loss results in unbalanced forces measured in tons.

Mr Morgan accused the VAF community of rumor, half-truth, and under-handed competitor activity. I appreciate hearing his account, but the included accusations are untrue. I gently chided him.

<<Developing propellers is probably one of the most difficult and unforgiving things to do in this business. I expect some failures, and have respect for guys that are willing to do it.>>

Agreed.
 
Glad to hear that it was a good outcome of this accident.

Pierre: You mentioned a retaing cable. Have thought about this earlier. Is it maybe something that is worth adding to our constructions? What is the risk of having a prop damage with vibrations ripping the enginge from its place? A cabel wont weight so much...
 
Skyhawk said:
Glad to hear that it was a good outcome of this accident.

Pierre: You mentioned a retaing cable. Have thought about this earlier. Is it maybe something that is worth adding to our constructions? What is the risk of having a prop damage with vibrations ripping the enginge from its place? A cabel wont weight so much...
Click to expand...

I have a picture of a Formula One race plane on short final with the engine hanging from the engine mount by the safety cable. Very sobering, picture's worth a thousand words. Will try to post.
tm
 
Risky props

Skyhawk said:
Glad to hear that it was a good outcome of this accident.

Pierre: You mentioned a retaing cable. Have thought about this earlier. Is it maybe something that is worth adding to our constructions? What is the risk of having a prop damage with vibrations ripping the enginge from its place? A cabel wont weight so much...
Click to expand...

The F-1's back then ('70's) used cut down Sensenich props..both chord width and length. They were also re-pitched for the 235MPH + speeds and 4000+ RPM's the guys were/are turning their 100 HP Continentals. Each prop came with a chart and an area of RPM's to avoid at all costs, around 2900-3100 or so..(resonance, nodes, modes,etc)...and to transition through that range as quickly as possible. The guys were also told to ferry with a wooden prop but some guys wouldn't do it because they were so much slower than the racing props and I'd guess that some guys were just hard-headed and blades were slung. That in itself is an instantly destructive vibration...one guy said that his instruments appeared to be 12 inches tall, it shook so bad for a few seconds.

Our current props by Catto, Sensenich and most other commonly used ones are nowhere near the risk of losing a blade....especially when staying within the manufacturers RPM limits.....kinda like putting a ballistic recovery chute on a 6G RV...not necessary since there's so little risk involved.

My .2c,

Regards,
 
Prop failure = bad.

So I'm a bit late to this thread, but I just dredged up a few pics of my little prop "incident"... actually it was an accident due to substantial damage to the airframe. It happened back in late '91 in my Cessna 310 freight dog days; the prop hub cracked during takeoff and shed two blades. At least the remaining blade feathered! Yep, it scared the cr@p outta me, and yea to the engineer(s) that designed the 310s cradle type engine mount. All 4 mounts were broken but the engine stayed on; this was a good thing.

The NTSB report;
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001212X18432&key=1

And a few photos... sorry about the lousy quality; it was a cheap camera in a dark hangar.
310prop02rk4.jpg

310prop03vc8.jpg

310prop04ln0.jpg

310prop05bx3.jpg
 


Not all inflight prop failures result a total wreck. :)

On April 12, 2000 I was flying from SunNFun to St. Louis at 10,500 when an exhaust pipe broke, went through the propeller and took one blade with it. Vibration was extreme to say the least, the canard was in a flutter with a 12 inch blur at the tips and I really thought my goose was cooked. Without thinking, the mixture was jerked to idle cut off and about as quick as you can say OH xxxx, the airplane became very calm and quiet. The prop had stopped turning and the machine was a glider and in one piece. Auburn, Alabama was about 10 miles behind and a dead stick landing was made without further ado. ATC helped with a vector and notified the FBO at Auburn, by the time I touched down there were 4 pickups with local guys and an ambulance waiting.

The engine was inspected as per the service bulletin on a prop strike and everything was normal somewhat to my surprise. Two weeks later, after securing another prop and exhaust pipe (it was #4), I flew on to St. Louis. I sold the airplane about a year later and it is still flying today.

I am convinced that if the prop had been metal, the engine would have departed also. Light weight wood props don't throw as much weight around and that saved the day.
 
Ryan, it has been a while since I read about Marc's incident. It would be nice to know if the cause was a failure to retorque the prop bolts (change in humidity).

I generally retorque my non-metal prop at oil changes. I even torqued it on a ramp in Florida on a trip since I live in Colorado. That may not be a problem change (going from dry to humid climate), but I did it anyway.
 
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