Falcon Propellers
04-12-2019, 08:15 AM
#1
Thread Starter
Falcon Propellers
So I went a bought a couple of these for my FG-30. They included some plastic inserts that I assume are to go in the hole for different sized shafts. I did not realize the hole is pretty much drilled to the max. Problem is the largest one does not fit the FG-30 and the prop is slightly loose on the shaft. Falcon does not have support on their website to ask them, so asking here instead. Is this going to be an issue?
04-14-2019, 02:26 AM
#5
Banned
The plastic parts are bushings. The plastic can be easily deformed causing a slight deformity to the shape/size of the hole. Simple temperature changes can do it. While ignored by most, this can have an impact on the proper centering and mounting of the prop. Which in turn can cause destructive vibrations to the engine and airframe. It's usually extremely minor and does not have an immediate impact so most simply ignore it if they notice it at all. I have found Aluminum works far better. Here's a source for reasonably priced aluminum bushings/spacers of all sizes. Contact their sales department should you need a mix of metric and SAE which I suspect could be your issue. i.e. SAE prop shaft with a metric prop hole/bushing. Or something like that.
Aluminum Spacers
Aluminum Spacers
Last edited by Appowner; 04-14-2019 at 02:36 AM.
04-14-2019, 06:27 AM
#6
Thread Starter
The shaft is 10.01 mm and the hole in the prop is 10.2 MM. Going to try the shrink tubing when I find my kit. I think it is in the garage. For now going to use an APC for the break in, found one in my trailer.
04-14-2019, 06:37 AM
#7
While that link is very useful for future needs, I didn't see anything with a 10mm OD and 8mm ID which is what I think the OP requires. The larger Faclcon props come drilled 10mm and the Saito shaft is most likely 8mm. Almost impossible to find a bushing with a 1mm wall. Shrink tube is pretty darned consistent in wall thickness.
OP and I were typing at the same time. That may even be a bit tight for shrink tube. You may need to do a wrap of thin tape. Not the best solution but one that will work. You may end up finding a bushing that fits the shaft and drill out the prop to accomidate the bushing.
OP and I were typing at the same time. That may even be a bit tight for shrink tube. You may need to do a wrap of thin tape. Not the best solution but one that will work. You may end up finding a bushing that fits the shaft and drill out the prop to accomidate the bushing.
Last edited by speedracerntrixie; 04-14-2019 at 06:41 AM.
04-15-2019, 05:35 AM
#9
Banned
And I do hope you check the balance and overall condition of the "found" APC prop.
I personally prefer wood props. I use to make my own props way back and still have my equipment for checking pitch, drill guides etc. Today I rarely find a wood prop that doesn't need some rework. And I've seen too many non-wood props with various flaws to trust them without question. The trick with the non-wood is being able to correct them. Especially carbon.
However, Falcon does do custom drilling. Check out their main web site: Falcon
Last edited by Appowner; 04-15-2019 at 06:04 AM.
04-15-2019, 07:27 AM
#10
To be honest, with a relatively smallish prop like that I'm not sure if I would worry about a .2mm discrepancy. As Appowner has said you haven't indicated if it is a wood or CF prop. CF is of course going to be a better prop ( theoretically ) as they are molded from CNC molds and CF is about as thermally stable as it gets. The CF Falcons do however have a wood core at the hub. If I were in your shoes I would carefully apply an even coat of medium CA to the inside of the hole. Repeat as nessesary until an adequate fit is reached and then balance as normal.
04-15-2019, 07:31 AM
#11
Thread Starter
Curious, is the prop used? And what is it made of? I'm assuming carbon but...... Sounds like the hole was either incorrectly bored or it has worn through use. In which case it could also be out of round and even slightly off center.
And I do hope you check the balance and overall condition of the "found" APC prop.
I personally prefer wood props. I use to make my own props way back and still have my equipment for checking pitch, drill guides etc. Today I rarely find a wood prop that doesn't need some rework. And I've seen too many non-wood props with various flaws to trust them without question. The trick with the non-wood is being able to correct them. Especially carbon.
However, Falcon does do custom drilling. Check out their main web site: Falcon
And I do hope you check the balance and overall condition of the "found" APC prop.
I personally prefer wood props. I use to make my own props way back and still have my equipment for checking pitch, drill guides etc. Today I rarely find a wood prop that doesn't need some rework. And I've seen too many non-wood props with various flaws to trust them without question. The trick with the non-wood is being able to correct them. Especially carbon.
However, Falcon does do custom drilling. Check out their main web site: Falcon
IT's a brand new wooden prop, and they use bushings to match the prop to the shaft, it just happens that the shaft on the FG-30 is 10 MM and the hole is slightly more than 10 MM. The APC is the recommended break in prop for the Saito, that is what they bench rate them on. I always balance my props before use, both horizontal and vertically.
04-15-2019, 04:48 PM
#12
Moderator
Of all the things that people overthink, prop hole size is very near the top of the list. It's right up there with synthetic 2 stroke oils and what makes the best competitive aerobatic plane. Here are the facts.
1. All the hole actually does is locate the prop in the right spot on the drive washer. Friction and mechanical bite hold it in place after that. There will be ZERO side forces of any kind on an installed prop.
2. A tapered hole is no better or no worse for locating the prop in the right spot than a straight hole. A tapered hole is, however, a lot easier to get sized exactly right and only requires one inexpensive tool.
What I would do in the OP's situation is CA the closest fitting insert into place then ream it to fit exactly. The fix will be permanent and easy. There is really no good reason to go to any more trouble than that.
1. All the hole actually does is locate the prop in the right spot on the drive washer. Friction and mechanical bite hold it in place after that. There will be ZERO side forces of any kind on an installed prop.
2. A tapered hole is no better or no worse for locating the prop in the right spot than a straight hole. A tapered hole is, however, a lot easier to get sized exactly right and only requires one inexpensive tool.
What I would do in the OP's situation is CA the closest fitting insert into place then ream it to fit exactly. The fix will be permanent and easy. There is really no good reason to go to any more trouble than that.
