Well if it was a hub failure then what's the next best material CF, aluminum... At least they have most likely don't have to remold it. So a fix shouldn't be too far off if they do decide to fix.

Originally Posted by Aros

I don't balance 4-blades (I don't even know how to be honest) but I have never had to in the past. I always check for proper rotation and the props were spinning perfectly. No wobble at all. However, I did note that the props were VERY close to the front of the cowl.

I think we have found our answer.

There needs to be more clearance between the prop swing and the front of the cowl. Both the P-47 and F4U have become victims to this issue. I will be contacting FMS about this. Something needs to be done here.

Aros, could you post a picture of whats left of the hub where the prop blades are attached. Thanks.

Originally Posted by v8truckin

Well if it was a hub failure then what's the next best material CF, aluminum... At least they have most likely don't have to remold it. So a fix shouldn't be too far off if they do decide to fix.

To me, failures like this speak of several things: A test to 'run to destruction' comes to mind where they set up a dynamic test simulating actual use to verify just what happens/happened and why. This method has been used much in the aircraft industry and with the power involved here, it seems a valid approach since the size of these is reaching beyond engineering like toys might be.

Imo. it calls for not only a material improvement but a hub design rework. The blades need to be gripped more thoroughly over their entire base/roots.

Originally Posted by gnats82

To me, failures like this speak of several things: A test to 'run to destruction' comes to mind where they set up a dynamic test simulating actual use to verify just what happens/happened and why. This method has been used much in the aircraft industry and with the power involved here, it seems a valid approach since the size of these is reaching beyond engineering like toys might be.

Imo. it calls for not only a material improvement but a hub design rework. The blades need to be gripped more thoroughly over their entire base/roots.

Good points and I agree....

I came very close to choosing one of these 1700mm FMS planes to buy earlier in the year. While I had no preconceptions about trouble here, I ideally didn't want a model with a four bladed prop due to the energy absorbed in drag to turn it.

I chose the A-rc/H-K P-40N and it came with it's own set of problems including a wonky propeller problem with the spinner running a bit out of true and out of balance. The thing about their design however that's held up to this point is that the blades are supported by a tight fitting socket at the base with total 360* contact around them. The blades cannot 'whip' in any direction. The only screw involved in securing it/them goes through without any clamping force whatever, just to secures the blade from 'leaving it's nest'.

This FMS part failure is crowding very closely into consumer product safety issues. FMS and any other manufacturer that is selling a set up like this with appeal to the general public to buy has got to take measures to police their product with more responsibility when they get this large and powerful. Even though I've been a modeler for many years and taken pains to be responsible for my works, I would pass on currently getting one of these even though I think Corsairs are magnificent (as are P-40s......) I was sooo close.

Aros,
When you get a chance, could you give the stock motor dimensions and any specs you can determine. Trying to figure out what an upgrade powerplant would be.
Thanks!
er

Someone said this but a good vari prop upgrade would solve this problem , actually eliminate it

Get a new prop for it and that should help rectify some f the safety concerns until FMS deals with the defect.

I have watched my 1400 mm corsair 4 blade prop flex back and forward as I throttled up and down and I have prop strikes on my cowl from blades being pushed back during incidents. I used washers behind my props to push them away from the cowl.

I just got a $4.99 4 blade, 16 x 10 P40 prop from hobbyking. I had to see what the quality was, going to inspect it tonight.

If FMS had taken the time to make cnc aluminum prop hubs for both 3 & 4 blade corsair props they woukd have been first on my list of spares.

eroeder, I will get the dimensions of the motor for you tomorrow...

One thing I wanted to mention was (in light of the obvious negative stuff going on with the hub issues) before the flight, two guys at our club walked up and thought the Corsair was a Top Flite or Hangar 9 composite. Why this is impressive is because one of them owns the Top Flite Giant Corsair and the other the ESM version. Both guys obviously know quality and for them to mistake the FMS Corsair for one of their planes was pretty awesome.

Granted, it was from 10 feet away when they were approaching the flight line but still.

Originally Posted by Ldm

Someone said this but a good vari prop upgrade would solve this problem , actually eliminate it

LDM,
I have a vario-prop in my hand as we speak.
Alloy hub ; ground adjustable pitch and beautifully engineered.
A rather expensive modification but as with the Sierra retracts on my P-40 worth every cent. This for me will solve the safety concerns I have with the stock hub.
Regards,

Ray.

Ray you have the magic elixir in your hands.

Originally Posted by Aros

Ray you have the magic elixir in your hands.

G'Day Aros,
I was truly sorry to learn of this mishap with your beautiful Corsair.
This is a model I have been waiting on for so long. I guess like everyone else !!
I would hate to see one of these prop/hub combinations explode close to a spectator group. FMS will solve the problem for sure but this will take more development time.
If I can source an airframe before any possible recall I will certainly be fitting the vario-prop.
I hope this all works out for you.
Regards,

Ray.

This is the little culprit along with the other variables we's all mentioned that is causeing the prop and hub failures and these catastrophic failures I've been talking about. It's basicaly the same setup on the P-47 and the F4U Corsair

Originally Posted by raybaines

LDM,
I have a vari-prop in my hand as we speak.
Alloy hub ; ground adjustable pitch and beautifully engineered.
A rather expensive modification but as with the Sierra retracts on my P-40 worth every cent. This for me will solve the safety concerns I have with the stock hub.
Regards,

Ray.

Are those the 473-16 16D 18.6" blades? I almost ordered those, but Christian recommended the 437-16 16D 17.2" blades for the 270-300kv motors, so that's what I ended up ordering.

Gary

Originally Posted by Sandancer

Are those the 473-16 16D 18.6" blades? I almost ordered those, but Christian recommended the 437-16 16D 17.2" blades for the 270-300kv motors, so that's what I ended up ordering.

Gary

Gary,
I have a set of 4713-16 16D 18.6" blades and a further set of 422-16 16D 16.6" blades.
Perhaps I will have to follow your lead and order the 17.2" blades to cover all bases !!

Ray.