Flying without spinner

Be careful on your "owner manufactured" statement. You would still be required to make that particular part in accordance with the appropriate approved part data. Owner manufactured only means you don't have to buy a PMA'd or otherwise approved method of manufacturing a part by someone else.

Without any holes in your starter ring gear you could add washers for balance to your prop bolts, assuming they are long enough.

skukum12 said:

Ok motosix, i believe every word. Now sell me a crushplate like that in black or greeen. Seriously, i need one now. Did you make that? Or where can i get one?

Click to expand...

The one pictured is the only one in existence and is for a Lycoming O-235 motor which is useless to 99% of Cubs. It is CNC'd, then EDMd for the logo, then anodized.

I draw up designs for people and work with local & online CNC places to help the parts get cut. One-off parts are not cheap, however designs get magnitudes cheaper as count goes up. Most online CNC places allow a huge range of anodizing colors, so black or green would be easy enough. As soon as I get my new prop in (with a crush plate to measure), I am going to get one for an Titan 340 designed and cut which might work for you if you have a Lyc 320? Which motor are you running?

Email me at dave AT ColoradoCub.com if that is easier so we don't drown this thread. You can see some of the other Cub parts in the works for my airplane at that web address as well.

edit: I should point out that everything stated above is for EXPERIMENTAL Cubs. Sorry, you certified guys have different hoops to jump through.

(the attachment is the real unsung hero on the nose of my Cub. It saved ~15 lbs all the way out at the prop!)

Here's one method I've seen for balancing. Normal prop bolt length limits washer numbers to achieve balance under head while maintaining thread penetration in the crankshaft flange. They are typically long enough to extend behind flange...or can be replaced with longer the meet specs. Being so close to the crank C/L meant more weight was needed than if the weight had been added further away from center...like under the bolt's head or on a spinner or ring gear. A skull cap goes over the assembly. Does it work? Yes. Lots of repair station equipment involved and log entry. Needs to be checked periodically for integrity and balance.

Gary

That above picture tells me, if that was my cowl, that a big spinner would be perhaps counter productive, that cowl was made for a skull cap or even no spinner. As opposed to the cowl gap I have (huge), obviously meant for a 12" dome, which led me down the path of a possible drag reduction or slight increase in speed.

Here's a good shot of the mini I've been using. I need a crush plate anyway for the Prince prop (unlike the ground adjustable types) so the only extra weight is the stem, an allen screw, and the dome, maybe 4 ozs. If I do end up putting it back on, I will, for the first time polish it, seems the least I can do. It's an idiot proof deal, and I really like the way it pops on or off with just the one allen head screw.

That above picture (T-Craft, pert sure) ) tells me, if that was my cowl, that a big spinner would be perhaps counter productive, that cowl was made for a skull cap or even no spinner. As opposed to the cowl gap I have (huge), obviously meant for a 12" dome, which led me down the path of a possible drag reduction or slight increase in speed.

Here's a good shot of the mini I've been using. I need a crush plate anyway for the Prince prop (unlike the ground adjustable types) so the only extra weight is the stem, an allen screw, and the dome, maybe 4 ozs. If I do end up putting it back on, I will, for the first time polish it, seems the least I can do. It's an idiot proof deal, and I like the way it pops on or off with just the one allen head screw.

Here's the new one. We all know Forest Green compliments Kubota Orange perfectly, right??? But since I had the paint already and also have a lot of other stuff the same color, I thought why not? I can't tell what color it is from the cockpit anyway.

Orange is easy to find if it decides to depart. The shape does fit the cowl's form nicely. I suppose in lieu of running and marking any spinner or backing plate offset just pulling some plugs and rotating the prop against a fixed reference would work.

How do you get to your home? Is there a road nearby?

Gary

A county gravel road, 1.5 miles to a paved 2 lane rd., then down the mountain and 3 minutes later I can get on I-15, and another 10 miles it joins with I-86. Point being, a great mix of boonie living combined with pretty easy access to the real world. I have a brother who lives on McGrath Rd BTW, he was good friends with the late Cliff Everts.

I did that when I set it up, had a clamped stick 1/8" away, plugs out, clamped tight, nothing moved when I drilled it, I was pretty surprised (teed off) to see it wasn't perfect. Not horrible by any means, but not perfect. I'll sneak up on the fine tuning next, the looks are actually starting to grow on me a bit.

When I carry my fat ebike on the rear rack of my Prius, the mileage hit from the drag is evident, with the real time fuel/mileage gauge I have. When I carry it on the same rack but now plugged into the hitch of the Silverado one ton flatbed, I can't tell any difference. That may be a simile for my lesser powered and lighter plane perhaps benefiting a bit from this spinner, whereas a 180 hp SC may just not notice as much, and even 2 mph gain is a pretty big gain when you're cruising in the 80's, I'll take it if I can get it.

Yes it's a small world isn't it? Lots of well seasoned folks live here, especially for the summers. All well armed BTW. How much do you think cooling drag detracts from your speed? Or other stuff like that exposed exhaust? Ever consider just a straight pipe to the tail and fly away from the noise?

Gary

Cooling drag, turbulence around the cowl with that big gap, who knows, I will find out, probably not a huge amount but just a little less can't hurt. The Swiss Muffler (goggle it) is an additional muffler to the stock under the cowl one, it and the Prince p tip prop make my plane one of the quietest in the air. It doesn't seem to hurt engine performance either, I've done static checks. Drag....yeah probably but I do it to keep my rural strip as stealthy as possible. I've run into newer neighbors at the mailbox, people that live down the road a mile, where I have flown over while climbing out, and they've said they never even knew I flew out of my place, much less been annoyed by the noise, that's why I do it, I call it the SBMS, sneaky bastard muffler system. It's the "if a tree falls in the forest...." thing, it didn't happen if no one heard you.

It was a cheap enough experiment, (forget the hours of labor, fitting etc.) but yielded absolutely no speed increase, so back on the wall it goes. Besides adding a bit over 2 pounds, it also made the top cowl removal just a bit more hassle. I did make a slight adjustment after making a mark on it while running, and was happy enough with the trueness of it. So at least for my bird it's usefulness is right up there with a hood ornament, KISS. I'm not disappointed at all, I just lost over 2 pounds!

Just tell the curious it's from a Cub that landed where you did once that had to be coptered out 'cause it was too short to takeoff

Gary

HA! I won't do that, but at some point I will share my findings with my fellow RANS S-7S pilots, who are hauling around those big spinners for no reason other than they look cool, and they think it is needed. One polish job on my good old skull cap spinner coming up.

While drag is always an important issue, it doesn't seem to be as important on airplanes which cruise less than about 105 mph. There seems to be a drag wall which appears in the 105 - 115 mph range. Above this speed streamlining seems to be more effective. Some where long ago I saw something to this effect in an old book. I have not been able to find this information in any recent searches. Yet my experiences indicate this is so.

In your case, a spinner would have the most effect on cooling airflow through the engine. Since you apparently have no cooling issues, the spinner is just eye candy.