Pre Rotator

[Mike Schallmann]

Yesterday I went to the Airport to Spin up my new blades and check the tracking --all was well for a couple of minutes -then BAM my prerotator SIEZED --ended up stripping the small gear-bending the shaft as well as cracking the cast aluminum bracket and bronze upper support-- all in all a total loss-- The unit was a Wunderlick and it was old as dirt!

Now I have two options --replace the whole upper unit ot go electric--

Does anybody have a used upper unit that they want to sell?

 

[Timchick]

Mike,
Too bad you missed Bensen Days. A couple guys had a lot of prerotator parts for sale at the used parts area. Don't know who had the stuff or how much was left over. Maybe Bud O'neal knows who had them.

 

[GYRO J]

what brand of blades were u trying out

 

[Adam H]

I've been working closely with Tom Milton and Nick Costa making Wunderlich prerotator parts ever since Dick passed away. I just want everyone to know that we are still making and shipping prerotators and parts.

Wunderlich's: (815) 838-0450

 

[Harry_S.]

I've been working closely with Tom Milton and Nick Costa making Wunderlich prerotator parts ever since Dick passed away. I just want everyone to know that we are still making and shipping prerotators and parts.

Wunderlich's: (815) 838-0450

And... A BIG THANK YOU... to you fellas.


Cheers

 

[Mike Schallmann]

Adam--Thanks for the info --called Tom and purchased a new upper unit!

 

[StanFoster]

Adam: I second that. Its nice to know I can get parts for mine should the need arise.


Stan

 

[Mike Schallmann]

The Blades were Rotorhawks -27' Dia. Spun them up to about 180 rpm --several times. On the final spin up (isnt it always ) the gear siezed to the shaft and it went KABOOM!

On a previous occasion -approx two years ago it was squeeking like crazy --so I pulled it apart and checked it out. The bushing in the gear was missing ang it was running on the shaft. The shaft was galled. I turned the shaft down about .030 and made a new silicone bronze bushing and lubed it with HP grease. It worked OK for the last two years.

The Wunderlick pre rotator is utter simplicity--but there is no provision for lubrication --so in the future I will shoot a couple of drops of oil down the shaft before every flying session--

A better solution would be to center drill the shaft and put in small cross holes -then install a Zerk fitting on the top of the shaft and grease the unit with HP grease-- but In dont know if that would reduce the strength of the shaft significantly---

 

[gyroplanes]

A better solution would be to center drill the shaft and put in small cross holes -then install a Zerk fitting on the top of the shaft and grease the unit with HP grease-- but In dont know if that would reduce the strength of the shaft significantly---

Thanks for the input, Mike. If and when I get caught up at Wunderlich's, I'll make a cross-drilled, greaseable shaft. The holes wouldn't have to be too large.

This only applies to the 2 gear, reversing upper units. The direct drive upper units have a grease fitting in the "support"

 

[Mike Schallmann]

Tom --sorry about spelling Dicks name wrong --the older I get the lousier I get about my spelling. I really cant believe I used to be a productive member of society--Im having to much fun being retired--- hope to see you at El Mirage--

 

[Mike Schallmann]

Due to a parts problem Tom is having a small delay in getting my upper unit---so-------
In truged to the airport and took the uppper unit back to my shop. After a little figuring I decided to see if In could fix it---Well after about two hours I had made a new shaft (center drilled and cross drilled ) with a grease gallery--The drive gear was totally ruined so I rummaged through my parts bin and came up with a gear from an old Chevy starter. the dia and teeth count were the same so I decided to use it. I was able to adapt it to retainer plate that was on the old gear.
I straightened the Bronze upper support unit and fixed the Aluminum housing.

I then assembled the whole thing and took it back to the Airport.

Fitted it to the gyro and powered it up. Spun the blade up to 180RPM several times and all worked OK.

I dont know how long it will last but I will use it until I get the new unit from Tom--

I will modify the new unit by putting in the grease gallery --this probably the best improvement --the unit should last forever if it properly greased--!

 

[Mike Schallmann]

Tim -what is the status of my upper prerorotator assembly-
i need it!

 

[StanFoster]

Mike: Sounds like you are good at improvising.....nice fix.


Stan

 

[gyro]

Mike, I figured that would be a wear problem when I bought my Pre-Rotator. I pulled the shaft and drilled and tapped a hole in the side of the brass casting and threaded in a grease zerk. I juice it up about twice a month and it has never let me down. I will be needing a new rubber wheel though...TOM...TOM...TOOOMMMM! Just giving you a heads up if you venture on this thread.

 

[gyroplanes]

Mini gun, There are two types of upper units. On one, the shaft spins in the upper bronze brace. This should have a grease fitting from Wunderlich's.

The other upper unit has a stationary shaft that is just held in place by the bronze "support" casting.

I suppose the stationary shaft could use a drilled passage to the bushing within the Bendix? Is this what you have?

Mike,
Tim?

If you mean Tom, the upper units are on a short hold, as the last useable gear was used. We had a tray of gears in stock. Unfortunately, all of those gears were drilled for a different application. (there are 3 look-a-like gears in the Wunderlich inventory. The ones we need are gone.
I found the vendor and ordered 50 more, they just arrived. I tried to do the internal, 6 step machining and gave up after a couple of hours (on one gear) I have my journeyman machinist coming in to show me how to efficiently perform this task since it's only a $27.00 part.

Sorry, it's all part of my learning curve.

 

[Mike Schallmann]

Tom--sorry about the misspelled name--when you get it done send it to me --

Thanks


Mike

 

[gyroplanes]

Don't worry about the name thing. I thought it was funny on the heels of the mis-spelled "Wunderlich" apology.

 

[Mike Schallmann]

Tom--just a bump --hows my prerotator coming?

 

[gyroplanes]

I've answered Mike in e-mail. See my post in the general thread for an announcement about Wunderlichs & Calumet Motorsports.