VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #1  
Old 03-10-2018, 08:03 PM
Dbro172's Avatar
Dbro172 Dbro172 is offline
 
Join Date: Apr 2012
Location: West Fargo, ND
Posts: 1,033
Default Balanced Prop

I recently installed a new three blade Catto and since I haven’t balanced my prop since 2014 I thought it would be a good idea. (I removed old weight prior to installing new prop). I dont know of anyone nearby with a balancer, except the local Jet Center and they charged me $550 on my old 182 and didn’t even change a thing; they just wrote something in the logbook indicating balance was within tolerance. Boy did that make me angry, considering I had balanced my RV prop before with a dynavibe in a matter of an hour or less.

So, I purchased a new Dynavibe Classic that arrived yesterday and put it to use this morning. This is a really nice kit and easy to use. I purchased the mounting bracket too which saved some time in fabricating a bracket. (Two small kids, not much time to spend at hangar)...

First run: .14 @ 90 degrees (heavy spot)
- Added a bolt to the starter ring at 270 degrees.
Second run: .17 @ 270: (too much weight)
- Moved bolt to 0 degrees
Third Run: Something random, no better.
- Added bolt @ original Heavy spot of 90
- Added bolt AND large Washer at 270
Fourth Run: .02 @ 135 - SUCCESS!

Less than an hour monkeying around. Now I have a Dynavibe on the shelf. If anyone is in the area and would like to try it out i’d Be happy to help.

PS: one advantage of balancing prop when its 25 degrees out is the engine doesn’t overheat!

__________________
Derek Hoeschen
EAA Tech Counselor
RV-9A #92103 - N803DK
G3X, Superior XO-320, Dual Pmags, Catto 3B
www.mykitlog.com/dbro172/

RV-8 #83565 - N184DK - building
1968 Mooney M20C - Sold
1956 C-182 - Sold

Last edited by Dbro172 : 03-10-2018 at 08:10 PM.
Reply With Quote
  #2  
Old 03-10-2018, 09:35 PM
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 423
Default

Man, that's a nice looking prop! Is that the new one with the nickel leading edge? That's the exact one that I'm planning for my new -7 build. It'll be interesting to get a pirep on its performance.
Reply With Quote
  #3  
Old 03-10-2018, 10:08 PM
Dbro172's Avatar
Dbro172 Dbro172 is offline
 
Join Date: Apr 2012
Location: West Fargo, ND
Posts: 1,033
Default

Yes, new prop with NLE. I believe this model has been out for a couple years. I had it pitched as a cruise prop and is a 67x71. Typically they would pitch an 0-320 as a 67x70. Previoulsy I could too easily surpass 2700 RPM with my two blade 70x70, even at high altitudes. (2800 + at 8500 DA).

Top speed is a few knots slower but cruise speed is higher at same RPMs and climb seems to exceed my two blade Catto and whirlwind. I have only flown in cold weather; 25 degrees to -10 F. Will be interesting to see how it performs at 95 degrees. I used to see 150ktas at 2550, now I can do that at 2450, so fuel burn is better too. Static RPM is 2160 and WOT @ 8500 DA (10,500 MSL) is about 2650 @ 158 KTAS. In short, climbs better, faster cruise, slower top end. I also ordered the same prop in a 67x70, in case i need better performance in the hot summer.

Only issue is that it has a vibration when reducing power in the pattern, perhaps between 1200 and 1400 RPM, shakes pretty good, never had that with the two blades....

3 blade prop helps to slow down better and sounds way different too. Less prop noise, more engine noise, cant say for sure if it is necessarily quieter, just different.

There’s my pirep!
__________________
Derek Hoeschen
EAA Tech Counselor
RV-9A #92103 - N803DK
G3X, Superior XO-320, Dual Pmags, Catto 3B
www.mykitlog.com/dbro172/

RV-8 #83565 - N184DK - building
1968 Mooney M20C - Sold
1956 C-182 - Sold
Reply With Quote
  #4  
Old 03-10-2018, 10:24 PM
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 423
Default

Great report! Where do you think the vibration is coming from? It sounds like you have the balance dialed in. I was talking to Catto the other day about a three blade prop for the IO-360 that I'll be installing in my -7. I'm not sure if it's the exact prop that you have or if a little different for the 360, but they mentioned some testing that they were doing on it...so it may be a different one from what you have.
Reply With Quote
  #5  
Old 03-17-2018, 11:20 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,318
Default

Quote:
Originally Posted by Dbro172 View Post
Yes, new prop with NLE. I believe this model has been out for a couple years. I had it pitched as a cruise prop and is a 67x71. Typically they would pitch an 0-320 as a 67x70. Previoulsy I could too easily surpass 2700 RPM with my two blade 70x70, even at high altitudes. (2800 + at 8500 DA).

Top speed is a few knots slower but cruise speed is higher at same RPMs and climb seems to exceed my two blade Catto and whirlwind. I have only flown in cold weather; 25 degrees to -10 F. Will be interesting to see how it performs at 95 degrees. I used to see 150ktas at 2550, now I can do that at 2450, so fuel burn is better too. Static RPM is 2160 and WOT @ 8500 DA (10,500 MSL) is about 2650 @ 158 KTAS. In short, climbs better, faster cruise, slower top end. I also ordered the same prop in a 67x70, in case i need better performance in the hot summer.

Only issue is that it has a vibration when reducing power in the pattern, perhaps between 1200 and 1400 RPM, shakes pretty good, never had that with the two blades....

3 blade prop helps to slow down better and sounds way different too. Less prop noise, more engine noise, cant say for sure if it is necessarily quieter, just different.

There’s my pirep!
I am curious if you confirmed a lower FF at the same cruise speed. My catto is also under pitched. I can pretty easily turn 2800+ at 8000, however, once I go LOP it settles out at 2730 at 8.0 GPH. I had considered adding another inch or two of pitch (currently 2 blade - 68X72 on an IO-320). However, I had assumed that the increased MAP at the lower RPM would nullify any fuel efficiency. I fly with 2 passenger at gross quite often, so kinda like the better climb and didn't want to give it up unless there is a real gain in fuel efficiency.

Larry
__________________
N64LR
RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress
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 03:14 AM.


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.