VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 07-18-2019, 08:45 AM
Ed_Wischmeyer's Avatar
Ed_Wischmeyer Ed_Wischmeyer is online now
 
Join Date: May 2005
Location: Savannah, GA
Posts: 1,018
Default Constant speed prop puzzler

So I finally decided to go from a fixed pitch Sensenich to a Hartzell constant speed on the RV-9A with an O-320. Took off the Sensenich fixed pitch metal prop and the 2 1/4" spacer (I measured it) but when we went to put on the constant speed prop, a surprise, and not a good one. The cowling and prop did not fit -- negative clearance.

If we remove the required 3/8" spacers between the prop hub and the spinner backplate, things just barely fit. The prop is an experimental prop but advertised as an HC-C2Y(L)-1BF, same as Van's sells. This prop shop says that this is the 502nd prop shipped for an RV.

Nobody around here or on any tech support line has any ideas, so it looks like I'll need a new cowling and some baffle modifications.

Any thoughts?

Thanks,

Ed
__________________
RV-9A at KSAV (Savannah, GA; dual experimental touch screens with autopilot, IFR GPS)
Previously RV-4, RV-8, RV-8A, AirCam, Cessna 175
ATP CFII PhD, so I have no excuses when I screw up
2019 dues slightly overpaid
Retired - "They used to pay me to be good, now I'm good for nothing."
Reply With Quote
  #2  
Old 07-18-2019, 09:08 AM
titanhank's Avatar
titanhank titanhank is offline
 
Join Date: Aug 2007
Location: Friendswood, Tx
Posts: 323
Default

Call sam at sabre manufacturing and order a constant speed prop spacer at whatever thickness you want. I went from a catto to a whirlwind. My prop spacer went from the 4” long down to a 2” spacer. This gives me about .40” of spinner to cowling clearence. I do not like making them exactly to plans at .25”. My conical mount engine will move around a little and make contact under high g loads without the extra space.

__________________
Rv-6
0-320/180+hp
10-1 pistons
Lycon port/polish
Dual pmags
EI Commander
Whirlwind 200rv prop
IFR Glass panel
Trutrak Vizion 385 Autopilot
Flightline Interior
Almost rv14 seat mod/cable locking
Electric seat back adjuster

Last edited by titanhank : 07-18-2019 at 09:15 AM.
Reply With Quote
  #3  
Old 07-18-2019, 09:19 AM
Ed_Wischmeyer's Avatar
Ed_Wischmeyer Ed_Wischmeyer is online now
 
Join Date: May 2005
Location: Savannah, GA
Posts: 1,018
Default

Quote:
Originally Posted by titanhank View Post
Call sam at sabre manufacturing and order a constant speed prop spacer at whatever thickness you want.
Thanks, but the problem is that there's not enough room for the prop with no spacer...
__________________
RV-9A at KSAV (Savannah, GA; dual experimental touch screens with autopilot, IFR GPS)
Previously RV-4, RV-8, RV-8A, AirCam, Cessna 175
ATP CFII PhD, so I have no excuses when I screw up
2019 dues slightly overpaid
Retired - "They used to pay me to be good, now I'm good for nothing."
Reply With Quote
  #4  
Old 07-18-2019, 09:21 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,280
Default

Quote:
Originally Posted by Ed_Wischmeyer View Post
Any thoughts?
Make sure the new spinner back plate is flat.
It is fairly common for them to be slightly cup shaped (which isn't a problem when the get captured between the prop extension and prop) and then it gets worse when you cut the center out of it for the constant speed prop.

I doubt that this could account for the 3/8" delta that you say you have but it could easily be 1/8 - 3/16"

BTW, the 2 1/4" spacer was originally developed by Sensenich for Van's to account for the dimensional difference between a standard Hartzell propeller hub and the aft face of the fixed pitch prop hub, so it technically should match.

Since others have very occasionally mentioned a fit problem when doing a prop conversion, I measured one of our currently unused propellers just to re-familiarize my memory with the details and it measures exactly 2 1/4 inches from the aft face of the hub (where it interfaces with the engine) to the aft face of the bushing with one washer added as specified in the install manual.

A couple of other things that could account for some dimensional loss....

- If the doubler was riveted onto the rear bulkhead on the front side instead of the rear where it is supposed to be.
-If you accidentally installed the new prop with the ring gear support not installed.
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #5  
Old 07-18-2019, 09:28 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,280
Default

One additional thought....


In the past, when a 4 inch extension was required for the old style cowl, two 2 1/4" spacers were stacked together.

Measure the spacer you removed and make sure it is 2 1/4 inches. It is possible someone got a hold of a prop that came with two 2 inch extensions and then just used one of them.

EDIT: Never mind.... I just noticed in your first post that you said you confirmed it was 2 1/4"
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #6  
Old 07-18-2019, 10:26 AM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 691
Default Prop Spacer

Quote:
Originally Posted by Ed_Wischmeyer View Post
Thanks, but the problem is that there's not enough room for the prop with no spacer...
I think he's talking about a custom spacer between the ring gear support and hub (like a fixed pitch prop spacer) to move the whole prop forward, not the spinner back plate spacer...
Reply With Quote
  #7  
Old 07-18-2019, 02:04 PM
Ed_Wischmeyer's Avatar
Ed_Wischmeyer Ed_Wischmeyer is online now
 
Join Date: May 2005
Location: Savannah, GA
Posts: 1,018
Default

Quote:
Originally Posted by skylor View Post
I think he's talking about a custom spacer between the ring gear support and hub (like a fixed pitch prop spacer) to move the whole prop forward, not the spinner back plate spacer...
That seems like quite a project for a constant speed prop -- lots of stress analysis, funny bolt patterns, not to mention oil through the hub and O-rings. Unless I'm missing something...
__________________
RV-9A at KSAV (Savannah, GA; dual experimental touch screens with autopilot, IFR GPS)
Previously RV-4, RV-8, RV-8A, AirCam, Cessna 175
ATP CFII PhD, so I have no excuses when I screw up
2019 dues slightly overpaid
Retired - "They used to pay me to be good, now I'm good for nothing."
Reply With Quote
  #8  
Old 07-18-2019, 02:44 PM
Mark Dickens's Avatar
Mark Dickens Mark Dickens is offline
 
Join Date: Apr 2012
Location: Collierville, TN (KFYE)
Posts: 1,243
Default

Ed, before I had my oil pump issues, I was dealing with the same issue you are, although it's with a Whirlwind prop instead of the Hartzell. I had a FP prop with a Saber 2.25" spacer and it fit well with my cowl. I initially installed the WW prop without the spacer and had the same problem you do. Bottom line, for me, what I am having to do is have a custom spinner and back plate made by Whirlwind to mate with a 1.25" spacer I bought from Sam. The spacers work fine with CS props, so no worries there. Just let Sam know your application is for CS and he'll include an o-ring that provides a seal between your crank boss and the spacer. Yep, it's not cheap, but nothing is, it seems
__________________
RV-8 #81077 Super Slow Build
Titan IOX-370, Dual P-Mags, AFP FM200A FI, Whirlwind 200RV CS Prop
First Flight 11/20/2016
www.marksrv8.com
Reply With Quote
  #9  
Old 07-18-2019, 03:11 PM
titanhank's Avatar
titanhank titanhank is offline
 
Join Date: Aug 2007
Location: Friendswood, Tx
Posts: 323
Default

Quote:
Originally Posted by Ed_Wischmeyer View Post
Thanks, but the problem is that there's not enough room for the prop with no spacer...

You need this spacer at whatever length you determine that will give you the correct spacing. Sam will make you one to your requirements. It will move the entire prop and back plate forward to whatever dimensions you want. Bolts on with an o-ring and the prop bolts to the spacer. Short of rebuilding all your cowling, this is the only quick way to do it.

__________________
Rv-6
0-320/180+hp
10-1 pistons
Lycon port/polish
Dual pmags
EI Commander
Whirlwind 200rv prop
IFR Glass panel
Trutrak Vizion 385 Autopilot
Flightline Interior
Almost rv14 seat mod/cable locking
Electric seat back adjuster
Reply With Quote
  #10  
Old 07-18-2019, 03:15 PM
Ed_Wischmeyer's Avatar
Ed_Wischmeyer Ed_Wischmeyer is online now
 
Join Date: May 2005
Location: Savannah, GA
Posts: 1,018
Default

Time to learn something new - what is a ring gear support, and where is there a picture of same? We haven't touched the ring gear. And then there's the issue of making sure the starter still engages properly.

The original builder did some "original" things, and there have been a few surprises already...

Thanks!

Ed
__________________
RV-9A at KSAV (Savannah, GA; dual experimental touch screens with autopilot, IFR GPS)
Previously RV-4, RV-8, RV-8A, AirCam, Cessna 175
ATP CFII PhD, so I have no excuses when I screw up
2019 dues slightly overpaid
Retired - "They used to pay me to be good, now I'm good for nothing."
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:56 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.