First foam build - Old Fogey - can't get it to fly!
- Thread starter petergaultney
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- advice old fogey speed build
petergaultney
New member
interesting - i hadn't considered reaming out the inside of the propeller to get a taper match, but maybe I'll get a chance to try that.
And actually, I'm waiting on 2 feet of Theraband blue, which (according to the link I posted) is a really strong O-ring replacement. So that may make a difference too!
And actually, I'm waiting on 2 feet of Theraband blue, which (according to the link I posted) is a really strong O-ring replacement. So that may make a difference too!
Yah, I've also heard a similar sound come from slow fly props that are spun at too high a RPM. With prop saver devices, you're just not going to get any sort of precision. While prop savers are a great idea, I find with the flimsy slow fly props that most vendors sell, they don't really save any props... I would just hard mount it and be secure in the knowledge that it's secure and balanced!
petergaultney
New member
Any particular recommendations for good slow fly props? I did some bench testing today and I think the major issue isn't the mount itself, but just that this prop can't handle more than about 7000rpm (and full throttle is probably around 12000). It seems strange to me now that the store and website recommended at 9x4.5 slow fly prop, and yet something that diameter really can't handle full throttle on even a relatively 'slow' 1000kv motor. Seems like something like the Old Fogey, designed to fly with a relatively small, high kv motor, would in fact be a lot better off with a 6x4.5 or 7x5.... if that would actually produce enough thrust.
I have a single collet-style mount that I bought along with a lot of stuff from a guy getting out of the hobby. It seems like it's meant for a slightly larger than 1/8" shaft (I don't have its original packaging to be sure either way) and won't stay on, so I am not using it. I guess I should try to find one that's definitely the right size, but I'm getting a little tired of buying things just to try them out and then decide they don't work like I hoped.
petergaultney
New member
UPDATE: I did some more bench testing, with a completely different motor that has a threaded shaft (so the prop can be mounted with a simple nut), and I was completely wrong about the prop. Looks like the problem is indeed that the "prop saver" simply isn't keeping minor oscillations from becoming major ones.
I'm posting a video here of the new prop spinning on the table. It's much quieter and smoother.
This other motor is a 75g, 900kv motor, so it's definitely overkill for the Old Fogey. But I'm tempted to give it a flight test anyway, because it performs so much more smoothly.
Do any of you have collet type adapters that you'd strongly recommend? I was looking through this list on Hobbyking, but they look almost exactly like the one that I have that doesn't hold tightly enough to the 3.17mm (1/8") shafts, so I'm reluctant to try them if they turn out not to work just like the one I've already got... Especially since I paid $20 (incl shipping and handling) to get the current set of prop savers that don't seem to work well with these props.
I'm posting a video here of the new prop spinning on the table. It's much quieter and smoother.
This other motor is a 75g, 900kv motor, so it's definitely overkill for the Old Fogey. But I'm tempted to give it a flight test anyway, because it performs so much more smoothly.
Do any of you have collet type adapters that you'd strongly recommend? I was looking through this list on Hobbyking, but they look almost exactly like the one that I have that doesn't hold tightly enough to the 3.17mm (1/8") shafts, so I'm reluctant to try them if they turn out not to work just like the one I've already got... Especially since I paid $20 (incl shipping and handling) to get the current set of prop savers that don't seem to work well with these props.
johnnyreb™
Low Speed-High Drag
Haven't had the chance to test them yet, but i have several of the tri-blade prop savers for a small twin engine project.
petergaultney
New member
those look interesting, but they don't seem to solve the main problem that I'm having, which is that the center holes (and the plastic circle adapters provided) in my props don't perfectly match my motors' shaft diameters. So there's no way to get the prop perfectly centered. Those prop savers would give a nice flat surface for the prop to mount against, but there would be no way to keep the prop centered on the shaft.
What I really need is a way to make my own circular adapters that are perfectly centered. Unfortunately, drilling out the props or the circle adapters always results in a prop that has a center hole that's slightly off-center.
What I really need is a way to make my own circular adapters that are perfectly centered. Unfortunately, drilling out the props or the circle adapters always results in a prop that has a center hole that's slightly off-center.
Hai-Lee
Old and Bold RC PILOT
I am unable to ascertain what your exact issue is because the names you are using are different to what I am used to using, (I think).
If you are using the collet type prop adapter and it is not tightening onto the motor shaft well enough there is a quick solution and that is to sand or file the cuts in the collet jaws to larger gap so that when you tighten the collet the jaws are able to move closer to each other or to put their force to the motor shaft and not the other jaws.
If you are using the aftermarket prop saver and it is not tightening centrally on the motor shaft I have used brass shims to pack the prop adapter on the shaft and then tighten the locking screws. (A drop of CA also helps).
As for the plastic adapters that come with props I fit the one which is just smaller diameter than the collet, spinner, or prop saver seat and drill or file out the centre hole to get the tight fit I require. Always check prop balance afterwards.
Where the spacer is just marginally too small to fit the adapter shaft I fit the spacer to the shaft forcefully without altering the hole size and then place the prop over the slightly enlarged spacer and tighten the collet until the prop is fully seated. It makes getting the prop a little difficult to remove later but a broken prop has no value so I just cut to broken prop into pieces and it all falls away.
Just some things I do when forced to!
).If you are using the collet type prop adapter and it is not tightening onto the motor shaft well enough there is a quick solution and that is to sand or file the cuts in the collet jaws to larger gap so that when you tighten the collet the jaws are able to move closer to each other or to put their force to the motor shaft and not the other jaws.
If you are using the aftermarket prop saver and it is not tightening centrally on the motor shaft I have used brass shims to pack the prop adapter on the shaft and then tighten the locking screws. (A drop of CA also helps).
As for the plastic adapters that come with props I fit the one which is just smaller diameter than the collet, spinner, or prop saver seat and drill or file out the centre hole to get the tight fit I require. Always check prop balance afterwards.
Where the spacer is just marginally too small to fit the adapter shaft I fit the spacer to the shaft forcefully without altering the hole size and then place the prop over the slightly enlarged spacer and tighten the collet until the prop is fully seated. It makes getting the prop a little difficult to remove later but a broken prop has no value so I just cut to broken prop into pieces and it all falls away.
Just some things I do when forced to!
petergaultney
New member
I think the collet type prop adapter is actually too big, not too small. It just won't clamp down hard enough, though it is at least in the right ballpark. This is the problem with 'inheriting' a bunch of stuff - you can't be sure exactly what it is, because it's not labeled.
The prop savers are holding onto the shaft just fine. I actually dremeled two flats on either side of the shaft for the set screws to bear down onto. So that's not an issue at all.
And yes, what you're saying about drilling out the plastic prop adapters/spacers makes sense - it's just that I find that I never manage to drill it out perfectly through the center - and a little bit of offset goes a long way to making the prop (or at least that particular plastic spacer) no longer usable.
The prop savers are holding onto the shaft just fine. I actually dremeled two flats on either side of the shaft for the set screws to bear down onto. So that's not an issue at all.
And yes, what you're saying about drilling out the plastic prop adapters/spacers makes sense - it's just that I find that I never manage to drill it out perfectly through the center - and a little bit of offset goes a long way to making the prop (or at least that particular plastic spacer) no longer usable.
petergaultney
New member
oh, interesting! I've not heard about anyone dynamically balancing props. I might have to give this a try.... though I'm not sure how you'd decide which side to add tape/weight to?
Hai-Lee
Old and Bold RC PILOT
For a simple method to enlarge the hole in the prop spacer is to use a soldering iron warmed up and turned off. Using a tapered iron tip slowly insert it into the existing hole and push slightly the plastic will melt slowly and will tend to self centre.
The trick is to get the iron JUST hot enough to slowly melt the plastic and not at normal soldering temperatures.
The method also stops the drill bits from hacking lumps out of the spacer and sometimes even your fingers.
Have Fun!
The trick is to get the iron JUST hot enough to slowly melt the plastic and not at normal soldering temperatures.
The method also stops the drill bits from hacking lumps out of the spacer and sometimes even your fingers.
Have Fun!
petergaultney
New member
That sounds like a good approach - I'll definitely be giving it a try.
