Failed prop hub on 1700mm p-51 hub

[RCjetdude]

If you've used CA on the assembly, I would suggest you take it apart and inspect it with a magnifying glass for spider webbing. If none are found and you've got the thing well balanced and have never had a prop strike, you're probably OK and you didn't torque the blade screws overly much. Sometimes, CA will fracture plastic in a week (like what happened to me with plastic control horns) or it may take weeks or months if the plastic is thick and the CA was not near holes (like the screw holes under the blades - that happened to me but thankfully, the blade came off when I was just throttling up on the ground). I found out the hard way.

I will inspect it however, I have been flying it for almost two years now with multiple nose over (prop strikes) and no issues to date. Granted, it could explode tomorrow if I flew it but so far no problems.

[Beeg]

I will inspect it however, I have been flying it for almost two years now with multiple nose over (prop strikes) and no issues to date. Granted, it could explode tomorrow if I flew it but so far no problems.

The prop hubs for the Corsair, Bearcat, P-47, etc.. are not as prone to breaking up as the hub/spinner arrangements on the P-51, P-38. etc. I've had zero problems with many light blade strikes on my FLRC Bearcat with stock and 1400mm FMS Corsair prop hubs so far with many flights since they were new.

[Scottchman]

Just wanted to pass along an up-date. I had a Stress Engineer check some numbers and at 7000 RPM you are seeing 2300 lbs. of CF force on that assembly. At 5500 RPM it drops to 1430. This might help explain things a little. Those Blades are much heavier than they should be. I checked with Motion RC and they had no information on the RPM the prop spins with the 360KV motor.

[Blewbayou]

They are pretty heavy, but I'm sure they have to be. Would be better if someone made carbon fiber props, be both lighter and stronger, I doubt lighter props in this configuration would survive unless they were carbon fiber.

[benjack71]

I have never had a problem. My understanding is you can not prop mod the new P-51 spinners

[Veltro]

What is a "1700mm P-51 Mustang by motion RC"? Are we talking about the the FMS 1700mm P-51?

[xviper]

What is a "1700mm P-51 Mustang by motion RC"? Are we talking about the the FMS 1700mm P-51?

Yes. Probably should have said, "sold by". There are other sellers. Don't know why the OP thought it was important to point out where he bought it from for the current topic at hand.

[Blewbayou]

Does it matter where it was bought, everyone knows it's not an issue from motion rc. I bought mine from motion rc because they have the best reputation out there.
I'm sure many have been sold over the years, 1700mm p51's that is and there is a few instances of props exploding, I don't think any one knows how many, I don't see it as wide spread. I think that more than likely, many are human error in assembly or balancing, maybe even some didn't balance. I'm not saying that in every case, some, I'm sure did it right, but maybe they got defective parts that were hard to detect.
if you have a 1,000 planes out there and 10 had failures, while not good for the people who suffered the loss, I think it's an acceptable failure rate. Nothing, will ever be 100% bullet proof.

[Wiggers58]

I had my propellor hub on my FMS P-51 1700mm implode today. Fortunately I was able to dead stick to a no damage belly landing in tall mowed grass! Unfortunately, the hub is underdesigned for the stresses on it. I was thinking I would find a quality one=piece four blade prop and a Truturn spinner, but couldn’t find any. Anyone have a source for a good four blade prop and spinner. I don’t want to replace mine with the same thing!

[xviper]

I had a similar incident with my 1700mm Corsair last year. When the prop assembly blew up, it was doing a high speed run. I think it was fatigue in the plastic as I had been flying this plane for many, many flights before it happened. I wish they made the blade holder out of metal. The blades and back plate and spinner on this assembly must be balance very precisely or the vibration will work at cracking it.
By chance did you use any Loctite on the bolts? Loctite is very bad on the plastic around the bolts. I've stopped using Loctite altogether on RC planes, in favor of FoamTac on threads.
I've looked for a 1-piece 4-blade prop but I can't find one that big. I also see that stock blades for these planes are hard to find and the blade holder and spinner is non-existent. Horizon still have some but who knows how long those will last.

[Johnnyrabuse]

All FMS prop hubs should be banned they have killed more planes than cancer

My advice on any plane that simulates a radial or zero or corsair or fw 190 etc should have a master air screw prop

Dump the spinner or modify it

As for something like a mustang get an after market one from say dubro and then install a master air screw

Exploding noses are yet another reason I avoid FMS

Total junk