SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Oct 08, 2012, 04:59 AM
Ldm
Registered User
Ldm's Avatar
United States, PA, Conestoga
Joined Jun 2006
8,390 Posts
P40 Sliding Canopy (0 min 44 sec)

This should show the unpainted spinner at the end when pull the camera back , it all carbon and pre balanced
Ldm is offline Find More Posts by Ldm
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 08, 2012, 05:51 AM
Coy, peruser of worlds
gnats82's Avatar
Augusta, KS USA
Joined Dec 2007
4,817 Posts
Aros -

That's the freakiest failure in a model I've ever seen, especially so for an electric plane.

The cowl may have touched the prop but, remember, due to the pitch of the blades, the trailing edge cannot dig in to tear it up just by rubbing.

I commented when your P-47 had the similar issue and I'm impressed the cowl is not the cause though I could be in error. To me, it's the blade and hub fit and the material of the hub itself. The blades would best be held in by shoulders or flanges around the entire blade base/root and be clamped firmly along the seams of the hub, maybe one bolt/screw through mid root, and made of a much better material.

Our fuel planes in this size category were putting out 2 to 2 1/2 h.p. and this electric system can't be too far behind. It needs to be taken into consideration also that abrupt changes in the attitude of the airplane puts heavy strain on these heavier hubs and blades the way they are due to inertia and gyroscopic forces. Serious stuff with this, models getting this large need serious engineering attention.
gnats82 is offline Find More Posts by gnats82
Last edited by gnats82; Oct 08, 2012 at 05:58 AM.
Reply With Quote
Old Oct 08, 2012, 08:37 AM
Registered User
Mitchie's Avatar
Canada, QC, Gatineau
Joined Jan 2011
1,957 Posts
Maybe a vario-prop would be in order for this bird. Looks like they have an 18.6" prop that would look right at home on this aircraft. (Need less lead to fly it too!)
Mitchie is online now Find More Posts by Mitchie
Reply With Quote
Old Oct 08, 2012, 10:37 AM
Registered User
struggleforlife's Avatar
The Netherlands, LI, Gennep
Joined Feb 2011
1,874 Posts
Man, Aros, you cannot catch a break, can you!?

These plastic spinners and blades are crappy on the 1400 series and I'm sure they are on the 1700 series.

You can't tell the difference between two and 4 blades, when flying. Also, 2 blades are more efficient. So why not a simpel 2 blade prop? That will never (!) explode.
struggleforlife is offline Find More Posts by struggleforlife
Reply With Quote
Old Oct 08, 2012, 11:10 AM
ronht
Joined Sep 2009
415 Posts
I'm just getting caught up with this and like everyone else I'm sorry to see the loss of this plane.

That said, I don't believe this is due to the prop rubbing the cowl. In the slow motion run of the video, you can clearly see 3 of the 4 blades departing the hub, leaving 1 blade and a running motor which creates an enormous amount of vibration through the airframe which theb shook the plane apart.

A good friend of mine had this happen to him in a full-size 3 bladed Pitts. One blade departed and shook the aircraft apart. Luckily for him, he had a chute on and was able to successfully leave the aircraft before it became a complete loss. He later said the vibration caused by losing a blade under power was incredible and nearly impossible to explain accurately.

This clearly looks like a hub failure to me rather than any problem with a blade rubbing the cowl.
ronht is offline Find More Posts by ronht
Reply With Quote
Old Oct 08, 2012, 11:24 AM
Registered User
United States, PA, Allentown
Joined Apr 2005
78 Posts
Aros need advice!

Aros saw the video of your V2 Corsair and the way it practically "exploded" in flight! What a beautiful flying model but at the same time so sorry to see the way it ended, I would agree and certainly appears that the prop failed and now I'm concerned about mine since I still haven't maiden it! I'm not sure of what to do, it's ready to go just waiting on good weather and our field to dry-up from all the rain! Are you going to be following up with FMS? What advice can you give me? I'm hesitant to fly it now!
orvel is offline Find More Posts by orvel
Reply With Quote
Old Oct 08, 2012, 11:29 AM
Experienced but not an Expert
seahawk1984's Avatar
United States, WA, Enumclaw
Joined May 2011
394 Posts
Quote:
Originally Posted by ronht View Post
I'm just getting caught up with this and like everyone else I'm sorry to see the loss of this plane.

That said, I don't believe this is due to the prop rubbing the cowl. In the slow motion run of the video, you can clearly see 3 of the 4 blades departing the hub, leaving 1 blade and a running motor which creates an enormous amount of vibration through the airframe which theb shook the plane apart.

A good friend of mine had this happen to him in a full-size 3 bladed Pitts. One blade departed and shook the aircraft apart. Luckily for him, he had a chute on and was able to successfully leave the aircraft before it became a complete loss. He later said the vibration caused by losing a blade under power was incredible and nearly impossible to explain accurately.

This clearly looks like a hub failure to me rather than any problem with a blade rubbing the cowl.
I tend to agree, I've watched the video over and over, one frame at a time here using the raw footage, so it's a much clearer image, and I'm starting to believe that there was catastrophic failure in the blades. Wouldn't the cowling have shown some sign of being hit? Aros, is the cowling plastic or foam? I know it might be difficult to tell since the plane did hit the ground nose first, but does the cowling show any signs of where the blades may have hit? I'm also thinking that we would have heard some sort of rubbing sound pryer to the event. And there is clearly one blade that is still spinning on the hubb after the explosion, and that doesn't appear to be hitting the cowling.

I will be checking my blades on my Starmax Mustang before my next flight (wich might be today), because I've nosed it down during taxi so much at our field. I should check for cracks in the blades right where the single screw goes in the hubb.

In any case, I agree, FMS needs to address this before they get a bunch of them on the market.
seahawk1984 is offline Find More Posts by seahawk1984
Reply With Quote
Old Oct 08, 2012, 11:43 AM
Field of Dreams Flyer
Mikemynameis's Avatar
San Pedro,Ca
Joined Sep 2004
9,314 Posts
Didnt you have a crash once before before the new flight with the new wing. Maybe that crash weakened it and you never saw the crack. Just my 2 cents
Mikemynameis is offline Find More Posts by Mikemynameis
Reply With Quote
Old Oct 08, 2012, 12:31 PM
ronht
Joined Sep 2009
415 Posts
The way the blades departed, they would not have hit the cowl and quite honestly, I don't see how the blades rubbing the cowl would result in this kind of failure.

From looking at the video, the 3 blades departed simultaneously in 3 directions at the same time, due to a catastrophic hub failure, leaving the one blade attached under-power creating an enormous amount of vibration from the "out of balance" condition.

Think about what a difference a small piece of tape makes when balancing the prop and hub and then consider the difference losing 3 of the 4 blades would do at high power. It's catastrophic, which is exactly what you see in the video.
ronht is offline Find More Posts by ronht
Reply With Quote
Old Oct 08, 2012, 12:55 PM
Coy, peruser of worlds
gnats82's Avatar
Augusta, KS USA
Joined Dec 2007
4,817 Posts
familiar news...

This is my posting about the failure of Aro's 1700mm P-47 prop and hub. It was considered that the Corsair would use the same parts...

Pg. 72

"Understanding what I do from past experience, especially with glow power over the course of 30 years or so, a cowl that had gotten loose and come forward into the prop would gotten the worst end of the damage, even if the prop was wood. There would have been the rustle of a lot of noise for warning and time to land without the prop disintegrating, more likely the cowl shredded a bit.

I'm still prompted to believe that this propeller design should have withstood that kind of contact and that it came apart the way it did is clear warning that it's not up to task well enough to depend on. I believe these built up props can be made better than what they are from what I've seen.

If the mounts were "ripped out" the way you say, it's cause to look closely if contact with the prop came first somehow, say from the hub coming apart, shocking and twisting the cowl mounts loose. That would be accentuated if the extreme imbalance caused the motor mounting to flex enough to allow the motor to wobble causing heavy contact while rotating. "
gnats82 is offline Find More Posts by gnats82
Reply With Quote
Old Oct 08, 2012, 02:51 PM
Fly & Have Fun..Enjoy the Ride
brandonmoon's Avatar
United States, AZ, Mesa
Joined Mar 2009
5,657 Posts
Quote:
Originally Posted by seahawk1984 View Post
I tend to agree, I've watched the video over and over, one frame at a time here using the raw footage, so it's a much clearer image, and I'm starting to believe that there was catastrophic failure in the blades. Wouldn't the cowling have shown some sign of being hit? Aros, is the cowling plastic or foam? I know it might be difficult to tell since the plane did hit the ground nose first, but does the cowling show any signs of where the blades may have hit? I'm also thinking that we would have heard some sort of rubbing sound pryer to the event. And there is clearly one blade that is still spinning on the hubb after the explosion, and that doesn't appear to be hitting the cowling.

I will be checking my blades on my Starmax Mustang before my next flight (wich might be today), because I've nosed it down during taxi so much at our field. I should check for cracks in the blades right where the single screw goes in the hubb.

In any case, I agree, FMS needs to address this before they get a bunch of them on the market.
Go back and look at his after crash posted pictures (specifically the close up the cowl)...you can clearly see on the top part of the dummy radial plastic piece in the cowl where the hub and it's screwsthe lightly poke out the back of the hub hit the cowl and broke a piece of it off (which is where the molded square cooler is)...just like on the p-47 incident he had happen...almost indetical occurences, plus you can see the blade rub marks arround the lip of the cowl ring.
brandonmoon is offline Find More Posts by brandonmoon
RCG Plus Member
Latest blog entry: Relocated back to Arizona
Reply With Quote
Old Oct 08, 2012, 02:56 PM
Fly & Have Fun..Enjoy the Ride
brandonmoon's Avatar
United States, AZ, Mesa
Joined Mar 2009
5,657 Posts
These Plastic Hubs should all be recalled by the manufacturer and replaced before some one gets hurt or fataly injured.
brandonmoon is offline Find More Posts by brandonmoon
RCG Plus Member
Latest blog entry: Relocated back to Arizona
Reply With Quote
Old Oct 08, 2012, 03:07 PM
Experienced but not an Expert
seahawk1984's Avatar
United States, WA, Enumclaw
Joined May 2011
394 Posts
Quote:
Originally Posted by brandonmoon View Post
Go back and look at his after crash posted pictures (specifically the close up the cowl)...you can clearly see on the top part of the dummy radial plastic piece in the cowl where the hub and it's screwsthe lightly poke out the back of the hub hit the cowl and broke a piece of it off (which is where the molded square cooler is)...just like on the p-47 incident he had happen...almost indetical occurences, plus you can see the blade rub marks arround the lip of the cowl ring.
Yep, I see what your talking about now, your talking about the center area of the cowling, not the blue outer area, which is what I was looking at. So the back of the prop hub was hitting that area there in the center, where the red is now showing. And not necessarily the blades them selves hitting the outer area of the cowling. And that's what I was looking at in the video. Watching for the blades to be hitting that, when what was actually happening was closer to the motor shaft which can't be seen in the video.

Wow, this has really sparked the conversation here in this thread hasn't it!
seahawk1984 is offline Find More Posts by seahawk1984
Reply With Quote
Old Oct 08, 2012, 03:10 PM
Fly & Have Fun..Enjoy the Ride
brandonmoon's Avatar
United States, AZ, Mesa
Joined Mar 2009
5,657 Posts
Yup...it's a serrious issue...for both the corsair and the P-47 which I also have along with many others.

Yes.... the center area on the molded dummy radial engine inside the cowl...it has a it has a square molded in silulated cooler piece? that protudes there (dead to center) and is just inline the the outer edge of the prop hub rotation where the bolts and lock nuts slightly protube out the back of the hub pice to hold the two halves together...and the clearence there is near minimal to none

It's the same on the P-47
brandonmoon is offline Find More Posts by brandonmoon
RCG Plus Member
Last edited by brandonmoon; Oct 08, 2012 at 03:17 PM.
Reply With Quote
Old Oct 08, 2012, 03:46 PM
Shameful Warbirdaholic.
Aros's Avatar
Maple Valley, WA
Joined Apr 2006
8,384 Posts
You're dead right Brandon. That is the culprit. I've emailed FMS, awaiting to hear their response.
Aros is offline Find More Posts by Aros
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product FMS North American P-51 D Mustang 1700mm (67 inches!!!) Beltpilot Electric Warbirds 9617 Today 11:55 AM
New Product FMS P-47 1700mm wingspan!!! HLC SHOP Electric Warbirds 2494 Today 03:09 AM
Wanted Needed Airfield/FMS F4U Corsair Spare Parts godofthunder77 Aircraft - Electric - Airplanes (FS/W) 2 Jun 29, 2011 04:17 PM
Discussion FMS/Airfield 800mm F4U Corsair norco kid Electric Warbirds 3 Apr 30, 2011 07:22 PM
Help! airfield/FMS F4U Corsair help kayla95 Electric Warbirds 2 Mar 24, 2011 07:12 PM