UHS Spinners

Anyone have any experience-comments on UHS spinners. Looking to possibly get an 8-9" UHS for 72" IVO Med GA 582-C. Thanks !

Ty,

I have a UHS fiberglass spinner on our Kitfox. Painted to match the plane. It has worked out fine - no problems with balance, etc. They are balanced as a unit (Bulkhead and cone) at the factory as I understand it. Certainly easy to trim to length. A person should be careful not to overtorque the screws which hold the cone to the bulkhead- factory recommends using blue locktite on the screws.

Sincerely,

Dave S
KF 7 Trigear
912ULS Warp Drive

Do you have "in flight adjust"? I tried two "UHS 9P" spinners(one for 2 blade, one for 3 blade) on a medium with "in flight adjust" and while it worked in general there were problems with the back plate warping. The 9P is extra long to accommodate the adjustment motor so any change was really obvious as wobbling at the tip. The "back" plate goes forward of the adjustment motor(at least that was the design when I was going through this). As you torque the six prop bolts the fiberglass warped even with extra wide washers and threw the spinner off center. Did it work...? yes, but not ideal and could have been a problem down the line. I imagine a squash plate would help, but that meant more weight up front and even longer prop bolts. Perhaps the ground adjust version allows the back plate to be placed behind the hub effectively creating a squash plate effect. I ended up changing to a Kiev for moment of inertia and weight reasons anyways so don't know how the condition would contribute to longevity. It also kinda scared me that the IVO is pretty specific on torque and relies on the knurled plates to grip the blades. Throw some fiberglass into the sandwich and you could have some torque changes with compression. Maybe I was over worried, but food for thought.

Ty,

I should have mentioned......on our S7 we have a ground adjustable warp drive prop and there is a 1/4" squash plate on top of the bulkhead. That may make a difference as Geowitz mentioned. I don't think the fender washers alone on top of the fiberglass bulkhead would be adequate. So our propshaft stack includes: Spacer, prop hub, bulkhead, squash plate, fender washers, AN washers, Bolts - this assembly has been stable.

Dave S

Thanks guys appreciate the info. UHS advised I use a 9p which does not seem right for the 582 72" Ivo 2 blade medium ground adjust with standard Ivo hub set-up. The 9p looks better suited for the IFA Ivo on a smooth cowl plane.

Ty

I had a problem with my UHS back plate. The fiberglass compressed each time I torqued the prop bolts and then loosened. This allowed the prop to operate below the specified torque, resulting in a crack in the prop blade from the bolt hole (two blade IVO). Since that time I'm running bare (well, no spinner anyway).

Hi Paul, Yikes !!! That does not sound good at all ! Years back I had the opportunity to chop up a spinner on my Lazair. Seems as though a hard working Dirt Dobber built a nest inside my spinner in the matter of week or two. The massive imbalance caused it to depart on the grôund during run up... thankfully. A large hunk of the spinner wacked me in the foot. No injury but Ow-weee did that hurt.
I think I'll look around for something else. My Lazair has custom spinner attachment plates turned from T-6 Billet. The spinners themselves are molded plastic that were made by the manufacturer of the Lazair. I've operated wîth them for a huge number of hours with no problems. I may need to think of something similar for the Kitfox. After hearing if your experience I think I'd rather go ugly than loose a blade. Thanks fôr the heads up.

Yeah, if I were to install one again I'd be looking for a metal back plate. Also, one with a good flange to support balace weights for dynamic balancing.

I am using the Whirlwind spinner and backplate (kind of spendy) which is carbon fiber. After 320 hours no loss of prop bolt torque at all.

Hi Jim, what prop are you using on your 912 ?

So far looks as though the simpliest way to cover up the ugly IVO GA adjuster and locknut would be with a Skullcap spinner. So far I've been unable to figure out exactly which one and from what source.

I am using the Whirlwind GA 3-blade 70" prop. I bought the prop and spinner as a package from Kitfox. No trimming necessary on the spinner. It all just goes together easy. As I said though, that carbon fibre spinner is spendy-$300+.

That's a nice set up. When I get a 912 I'll be looking at the Whirlwind or Prince prop. $300 really isn't that awful for confidence that the spinner (and prop) are going stay front and center.

Like Jim, I have a Whirlwind and one of their carbon fiber spinners. For the classic Kitfox look, with the round cowl, the little skull cap spinners look great, but keep in mind that you eliminate the best & possibly only practical location to install balance weights if you don't use a full-size spinner.

Hi John , I'm not clear on how one would add weights with a regular spinner vs. skullcap ?

I read an archive post here where a guy had his $50 skullcap spinner come loose and destroy his expensive new wood prop. My ugly exposed IVO hub is looking better by the day. I don't like the looks of how some cheap skullcaps are attached.

Hi Ty,
The "skullcaps" that I've seen on the IVO props are relatively small diameter, attached with a single screw through the center. The small diameter equals a shorter moment arm for the weights attached to the inside surface of the spinner. So it would take more weight to get the same effect than if using weights attached to the inside of the backing plate flange on a "standard" spinner design. That flange is the usual and very convenient location for mounting balance weights. Trying to install reliable weights to the inside of a skullcap would be a difficult trick. On a Lyc engine with a large starter ring gear, weights can frequently be easily added to that flywheel. It's usually not desireable or convenient to add or subtract weight directly to/from a propeller in the field.

In that case we used longer prop bolts and added the washers there.

Yeah, there are all kinds of ways to do it... it's just that being able to add weight to the spinner back plate is so much easier. Test weights are easily & quickly applied using the spinner screws. I should have thought of that, Larry. Applying weights to a skullcap is probably never done... I just got off on a tangent trying to advocate for a bigger spinner with a back plate as far as dynamic balancing is concerned. Self-adhesive weights can be easily adjusted to a tiny fraction of a gram, there are many more possible positions for weight installation and the weight is further from the center of the prop, allowing for a more accurate balance with less/fewer weight(s). However it's done, it'll probably be a big improvement over an unbalanced prop. Like I said, I've balanced hundreds of props - on Lycoming, Continental, Rotax, Jabiru, Subaru, VW, etc., and only once in about 20 years did I find one that was so perfectly balanced that I didn't even touch it after checking - a Quickie II with an O-200 Cont. The out of balance condition is usually substantial and the pilot doesn't even know it.

John, follow on question to balancing: Does dynamically balancing a prop on a certified aircraft require an A&P sign off? I'm guessing it does.

Yes it does, Paul. I've done a few factory built aircraft over the years, when the owner's mechanic was willing to sign it off. I've pretty much done nothing but experimental homebuilts with the builder helping & making his logbook entries.

My story is that I bought the machine at a time in my life when I had a little more money than sense I guess, but it's been great to have. Shortly after I finished my T-18 about 25 years ago a local prop shop offered a "special" price of $250 to our EAA chapter (#43) for a dynamic balance job. They used an old Chadwick Helmuth balancer with the hand-held strobe light, etc. The quality of the job was dependent on the experience & skill of the operator. Long story short, after about 45 minutes, the guy said that was it. The numbers weren't particularily good, but I noticed a good improvement and could see the potential if a really good job was done. The newer technology was becoming available & more affordable, with micro-processors & photoelectric sensors, simplifying & making the whole thing pretty easy. I bought one of the ACES units & have never regretted it. It's a nice compact unit, but the newer ones like Dorsal has are even more compact. I've balanced all kinds of things with mine, including blower wheels, car engine flywheels, etc.

Thanks guys, just placed my order with kf, all new engine and prop.

Curious what prop combination you decided on ?

If you’re looking for a quality spinner I’d recommend Whirlwind. They are carbon fiber and much stronger than the fiberglass ones. I have the 9.75” from Whirlwind and the craftsmanship is exceptional. The backplate is also carbon fiber and won’t crush or warp. UHS may be fine, but you get what you pay for.

I bought a UHS. I broke it during install. I sent it back and they couldn't fix it. They sent me a new one and charged me. I got 8 of the 9 screws in the spinner, but the 9th screw hole needed to be tapped. I bought a tap and die set and learned how to do that too. Im 400 plus dollars into a SPINNER! oh, did I say that it needs to be sanded and painted because the primer has a little run in the paint.
No, UHS does not get my vote and yes, i'm telling the distributor.

I'll add that my whirlwind spinner arrived in beautiful finish. I then proceeded to paint it and polish it. Finally, I dropped it onto the pavement from about three feet, it hit right onto the tip. Not a mar one.

Reviving an old thread. I called UHS and asked about delivery time for a spinner and was quoted 2 weeks. I'm well past 4 weeks and still nothing. The guy I bought it thru keeps calling and isn't getting any info from UHS. Is anybody here friends with the guy who owns UHS? Is he not well or is he just overpromising? I tried calling yesterday and today and got their voice mail. This is our prime flying season and I hate flying without one. I need a spinner and I'm open to any alternate suggestions. I have an IFA adjustable IVO prop on a Rotax 912ULS.

Thanks!

How did it go? Did you get your spinner?

Eventually it showed up and required a lot of fitting.

Quote:

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Originally Posted by rc300xs

How did it go? Did you get your spinner?

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I end up going with someone else, no ideal where they are